Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 15126 insertions, 0 deletions

diff --git a/js/src/jit/CodeGenerator.cpp b/js/src/jit/CodeGenerator.cpp
new file mode 100644
index 0000000000..1e2ff969fb
--- /dev/null
+++ b/js/src/jit/CodeGenerator.cpp
@@ -0,0 +1,15126 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jit/CodeGenerator.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Casting.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/EndianUtils.h"
+#include "mozilla/EnumeratedArray.h"
+#include "mozilla/EnumeratedRange.h"
+#include "mozilla/IntegerTypeTraits.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Tuple.h"
+#include "mozilla/Unused.h"
+
+#include <limits>
+#include <type_traits>
+#include <utility>
+
+#include "jslibmath.h"
+#include "jsmath.h"
+#include "jsnum.h"
+
+#include "builtin/Eval.h"
+#include "builtin/MapObject.h"
+#include "builtin/RegExp.h"
+#include "builtin/SelfHostingDefines.h"
+#include "builtin/String.h"
+#include "gc/Nursery.h"
+#include "irregexp/RegExpTypes.h"
+#include "jit/BaselineCodeGen.h"
+#include "jit/CompileInfo.h"
+#include "jit/InlineScriptTree.h"
+#include "jit/Invalidation.h"
+#include "jit/IonIC.h"
+#include "jit/IonScript.h"
+#include "jit/JitcodeMap.h"
+#include "jit/JitFrames.h"
+#include "jit/JitRealm.h"
+#include "jit/JitRuntime.h"
+#include "jit/JitSpewer.h"
+#include "jit/JitZone.h"
+#include "jit/Linker.h"
+#include "jit/Lowering.h"
+#include "jit/MIRGenerator.h"
+#include "jit/MoveEmitter.h"
+#include "jit/RangeAnalysis.h"
+#include "jit/SafepointIndex.h"
+#include "jit/SharedICHelpers.h"
+#include "jit/StackSlotAllocator.h"
+#include "jit/VMFunctions.h"
+#include "jit/WarpSnapshot.h"
+#include "js/experimental/JitInfo.h"  // JSJit{Getter,Setter}CallArgs, JSJitMethodCallArgsTraits, JSJitInfo
+#include "js/friend/DOMProxy.h"  // JS::ExpandoAndGeneration
+#include "js/RegExpFlags.h"      // JS::RegExpFlag
+#include "js/ScalarType.h"       // js::Scalar::Type
+#include "proxy/DOMProxy.h"
+#include "util/CheckedArithmetic.h"
+#include "util/Unicode.h"
+#include "vm/ArrayBufferViewObject.h"
+#include "vm/AsyncFunction.h"
+#include "vm/AsyncIteration.h"
+#include "vm/BuiltinObjectKind.h"
+#include "vm/FunctionFlags.h"  // js::FunctionFlags
+#include "vm/MatchPairs.h"
+#include "vm/PlainObject.h"  // js::PlainObject
+#include "vm/RegExpObject.h"
+#include "vm/RegExpStatics.h"
+#include "vm/StringObject.h"
+#include "vm/StringType.h"
+#include "vm/TraceLogging.h"
+#include "vm/TypedArrayObject.h"
+#ifdef MOZ_VTUNE
+#  include "vtune/VTuneWrapper.h"
+#endif
+#include "wasm/WasmGC.h"
+#include "wasm/WasmStubs.h"
+
+#include "builtin/Boolean-inl.h"
+#include "jit/ABIFunctionList-inl.h"
+#include "jit/MacroAssembler-inl.h"
+#include "jit/shared/CodeGenerator-shared-inl.h"
+#include "jit/shared/Lowering-shared-inl.h"
+#include "jit/TemplateObject-inl.h"
+#include "jit/VMFunctionList-inl.h"
+#include "vm/Interpreter-inl.h"
+#include "vm/JSScript-inl.h"
+
+using namespace js;
+using namespace js::jit;
+
+using JS::GenericNaN;
+using mozilla::AssertedCast;
+using mozilla::DebugOnly;
+using mozilla::FloatingPoint;
+using mozilla::Maybe;
+using mozilla::NegativeInfinity;
+using mozilla::PositiveInfinity;
+
+using JS::ExpandoAndGeneration;
+
+namespace js {
+namespace jit {
+
+#ifdef CHECK_OSIPOINT_REGISTERS
+template <class Op>
+static void HandleRegisterDump(Op op, MacroAssembler& masm,
+                               LiveRegisterSet liveRegs, Register activation,
+                               Register scratch) {
+  const size_t baseOffset = JitActivation::offsetOfRegs();
+
+  // Handle live GPRs.
+  for (GeneralRegisterIterator iter(liveRegs.gprs()); iter.more(); ++iter) {
+    Register reg = *iter;
+    Address dump(activation, baseOffset + RegisterDump::offsetOfRegister(reg));
+
+    if (reg == activation) {
+      // To use the original value of the activation register (that's
+      // now on top of the stack), we need the scratch register.
+      masm.push(scratch);
+      masm.loadPtr(Address(masm.getStackPointer(), sizeof(uintptr_t)), scratch);
+      op(scratch, dump);
+      masm.pop(scratch);
+    } else {
+      op(reg, dump);
+    }
+  }
+
+  // Handle live FPRs.
+  for (FloatRegisterIterator iter(liveRegs.fpus()); iter.more(); ++iter) {
+    FloatRegister reg = *iter;
+    Address dump(activation, baseOffset + RegisterDump::offsetOfRegister(reg));
+    op(reg, dump);
+  }
+}
+
+class StoreOp {
+  MacroAssembler& masm;
+
+ public:
+  explicit StoreOp(MacroAssembler& masm) : masm(masm) {}
+
+  void operator()(Register reg, Address dump) { masm.storePtr(reg, dump); }
+  void operator()(FloatRegister reg, Address dump) {
+    if (reg.isDouble()) {
+      masm.storeDouble(reg, dump);
+    } else if (reg.isSingle()) {
+      masm.storeFloat32(reg, dump);
+    } else if (reg.isSimd128()) {
+      MOZ_CRASH("Unexpected case for SIMD");
+    } else {
+      MOZ_CRASH("Unexpected register type.");
+    }
+  }
+};
+
+class VerifyOp {
+  MacroAssembler& masm;
+  Label* failure_;
+
+ public:
+  VerifyOp(MacroAssembler& masm, Label* failure)
+      : masm(masm), failure_(failure) {}
+
+  void operator()(Register reg, Address dump) {
+    masm.branchPtr(Assembler::NotEqual, dump, reg, failure_);
+  }
+  void operator()(FloatRegister reg, Address dump) {
+    if (reg.isDouble()) {
+      ScratchDoubleScope scratch(masm);
+      masm.loadDouble(dump, scratch);
+      masm.branchDouble(Assembler::DoubleNotEqual, scratch, reg, failure_);
+    } else if (reg.isSingle()) {
+      ScratchFloat32Scope scratch(masm);
+      masm.loadFloat32(dump, scratch);
+      masm.branchFloat(Assembler::DoubleNotEqual, scratch, reg, failure_);
+    } else if (reg.isSimd128()) {
+      MOZ_CRASH("Unexpected case for SIMD");
+    } else {
+      MOZ_CRASH("Unexpected register type.");
+    }
+  }
+};
+
+void CodeGenerator::verifyOsiPointRegs(LSafepoint* safepoint) {
+  // Ensure the live registers stored by callVM did not change between
+  // the call and this OsiPoint. Try-catch relies on this invariant.
+
+  // Load pointer to the JitActivation in a scratch register.
+  AllocatableGeneralRegisterSet allRegs(GeneralRegisterSet::All());
+  Register scratch = allRegs.takeAny();
+  masm.push(scratch);
+  masm.loadJitActivation(scratch);
+
+  // If we should not check registers (because the instruction did not call
+  // into the VM, or a GC happened), we're done.
+  Label failure, done;
+  Address checkRegs(scratch, JitActivation::offsetOfCheckRegs());
+  masm.branch32(Assembler::Equal, checkRegs, Imm32(0), &done);
+
+  // Having more than one VM function call made in one visit function at
+  // runtime is a sec-ciritcal error, because if we conservatively assume that
+  // one of the function call can re-enter Ion, then the invalidation process
+  // will potentially add a call at a random location, by patching the code
+  // before the return address.
+  masm.branch32(Assembler::NotEqual, checkRegs, Imm32(1), &failure);
+
+  // Set checkRegs to 0, so that we don't try to verify registers after we
+  // return from this script to the caller.
+  masm.store32(Imm32(0), checkRegs);
+
+  // Ignore clobbered registers. Some instructions (like LValueToInt32) modify
+  // temps after calling into the VM. This is fine because no other
+  // instructions (including this OsiPoint) will depend on them. Also
+  // backtracking can also use the same register for an input and an output.
+  // These are marked as clobbered and shouldn't get checked.
+  LiveRegisterSet liveRegs;
+  liveRegs.set() = RegisterSet::Intersect(
+      safepoint->liveRegs().set(),
+      RegisterSet::Not(safepoint->clobberedRegs().set()));
+
+  VerifyOp op(masm, &failure);
+  HandleRegisterDump<VerifyOp>(op, masm, liveRegs, scratch, allRegs.getAny());
+
+  masm.jump(&done);
+
+  // Do not profile the callWithABI that occurs below.  This is to avoid a
+  // rare corner case that occurs when profiling interacts with itself:
+  //
+  // When slow profiling assertions are turned on, FunctionBoundary ops
+  // (which update the profiler pseudo-stack) may emit a callVM, which
+  // forces them to have an osi point associated with them.  The
+  // FunctionBoundary for inline function entry is added to the caller's
+  // graph with a PC from the caller's code, but during codegen it modifies
+  // Gecko Profiler instrumentation to add the callee as the current top-most
+  // script. When codegen gets to the OSIPoint, and the callWithABI below is
+  // emitted, the codegen thinks that the current frame is the callee, but
+  // the PC it's using from the OSIPoint refers to the caller.  This causes
+  // the profiler instrumentation of the callWithABI below to ASSERT, since
+  // the script and pc are mismatched.  To avoid this, we simply omit
+  // instrumentation for these callWithABIs.
+
+  // Any live register captured by a safepoint (other than temp registers)
+  // must remain unchanged between the call and the OsiPoint instruction.
+  masm.bind(&failure);
+  masm.assumeUnreachable("Modified registers between VM call and OsiPoint");
+
+  masm.bind(&done);
+  masm.pop(scratch);
+}
+
+bool CodeGenerator::shouldVerifyOsiPointRegs(LSafepoint* safepoint) {
+  if (!checkOsiPointRegisters) {
+    return false;
+  }
+
+  if (safepoint->liveRegs().emptyGeneral() &&
+      safepoint->liveRegs().emptyFloat()) {
+    return false;  // No registers to check.
+  }
+
+  return true;
+}
+
+void CodeGenerator::resetOsiPointRegs(LSafepoint* safepoint) {
+  if (!shouldVerifyOsiPointRegs(safepoint)) {
+    return;
+  }
+
+  // Set checkRegs to 0. If we perform a VM call, the instruction
+  // will set it to 1.
+  AllocatableGeneralRegisterSet allRegs(GeneralRegisterSet::All());
+  Register scratch = allRegs.takeAny();
+  masm.push(scratch);
+  masm.loadJitActivation(scratch);
+  Address checkRegs(scratch, JitActivation::offsetOfCheckRegs());
+  masm.store32(Imm32(0), checkRegs);
+  masm.pop(scratch);
+}
+
+static void StoreAllLiveRegs(MacroAssembler& masm, LiveRegisterSet liveRegs) {
+  // Store a copy of all live registers before performing the call.
+  // When we reach the OsiPoint, we can use this to check nothing
+  // modified them in the meantime.
+
+  // Load pointer to the JitActivation in a scratch register.
+  AllocatableGeneralRegisterSet allRegs(GeneralRegisterSet::All());
+  Register scratch = allRegs.takeAny();
+  masm.push(scratch);
+  masm.loadJitActivation(scratch);
+
+  Address checkRegs(scratch, JitActivation::offsetOfCheckRegs());
+  masm.add32(Imm32(1), checkRegs);
+
+  StoreOp op(masm);
+  HandleRegisterDump<StoreOp>(op, masm, liveRegs, scratch, allRegs.getAny());
+
+  masm.pop(scratch);
+}
+#endif  // CHECK_OSIPOINT_REGISTERS
+
+// Before doing any call to Cpp, you should ensure that volatile
+// registers are evicted by the register allocator.
+void CodeGenerator::callVMInternal(VMFunctionId id, LInstruction* ins,
+                                   const Register* dynStack) {
+  TrampolinePtr code = gen->jitRuntime()->getVMWrapper(id);
+  const VMFunctionData& fun = GetVMFunction(id);
+
+  // Stack is:
+  //    ... frame ...
+  //    [args]
+#ifdef DEBUG
+  MOZ_ASSERT(pushedArgs_ == fun.explicitArgs);
+  pushedArgs_ = 0;
+#endif
+
+#ifdef CHECK_OSIPOINT_REGISTERS
+  if (shouldVerifyOsiPointRegs(ins->safepoint())) {
+    StoreAllLiveRegs(masm, ins->safepoint()->liveRegs());
+  }
+#endif
+
+#ifdef DEBUG
+  if (ins->mirRaw()) {
+    MOZ_ASSERT(ins->mirRaw()->isInstruction());
+    MInstruction* mir = ins->mirRaw()->toInstruction();
+    MOZ_ASSERT_IF(mir->needsResumePoint(), mir->resumePoint());
+
+    // If this MIR instruction has an overridden AliasSet, set the JitRuntime's
+    // disallowArbitraryCode_ flag so we can assert this VMFunction doesn't call
+    // RunScript. Whitelist MInterruptCheck and MCheckOverRecursed because
+    // interrupt callbacks can call JS (chrome JS or shell testing functions).
+    bool isWhitelisted = mir->isInterruptCheck() || mir->isCheckOverRecursed();
+    if (!mir->hasDefaultAliasSet() && !isWhitelisted) {
+      const void* addr = gen->jitRuntime()->addressOfDisallowArbitraryCode();
+      masm.move32(Imm32(1), ReturnReg);
+      masm.store32(ReturnReg, AbsoluteAddress(addr));
+    }
+  }
+#endif
+
+  // Push an exit frame descriptor. If |dynStack| is a valid pointer to a
+  // register, then its value is added to the value of the |framePushed()| to
+  // fill the frame descriptor.
+  if (dynStack) {
+    masm.addPtr(Imm32(masm.framePushed()), *dynStack);
+    masm.makeFrameDescriptor(*dynStack, FrameType::IonJS,
+                             ExitFrameLayout::Size());
+    masm.Push(*dynStack);  // descriptor
+  } else {
+    masm.pushStaticFrameDescriptor(FrameType::IonJS, ExitFrameLayout::Size());
+  }
+
+  // Call the wrapper function.  The wrapper is in charge to unwind the stack
+  // when returning from the call.  Failures are handled with exceptions based
+  // on the return value of the C functions.  To guard the outcome of the
+  // returned value, use another LIR instruction.
+  uint32_t callOffset = masm.callJit(code);
+  markSafepointAt(callOffset, ins);
+
+#ifdef DEBUG
+  // Reset the disallowArbitraryCode flag after the call.
+  {
+    const void* addr = gen->jitRuntime()->addressOfDisallowArbitraryCode();
+    masm.push(ReturnReg);
+    masm.move32(Imm32(0), ReturnReg);
+    masm.store32(ReturnReg, AbsoluteAddress(addr));
+    masm.pop(ReturnReg);
+  }
+#endif
+
+  // Remove rest of the frame left on the stack. We remove the return address
+  // which is implicitly poped when returning.
+  int framePop = sizeof(ExitFrameLayout) - sizeof(void*);
+
+  // Pop arguments from framePushed.
+  masm.implicitPop(fun.explicitStackSlots() * sizeof(void*) + framePop);
+  // Stack is:
+  //    ... frame ...
+}
+
+template <typename Fn, Fn fn>
+void CodeGenerator::callVM(LInstruction* ins, const Register* dynStack) {
+  VMFunctionId id = VMFunctionToId<Fn, fn>::id;
+  callVMInternal(id, ins, dynStack);
+}
+
+// ArgSeq store arguments for OutOfLineCallVM.
+//
+// OutOfLineCallVM are created with "oolCallVM" function. The third argument of
+// this function is an instance of a class which provides a "generate" in charge
+// of pushing the argument, with "pushArg", for a VMFunction.
+//
+// Such list of arguments can be created by using the "ArgList" function which
+// creates one instance of "ArgSeq", where the type of the arguments are
+// inferred from the type of the arguments.
+//
+// The list of arguments must be written in the same order as if you were
+// calling the function in C++.
+//
+// Example:
+//   ArgList(ToRegister(lir->lhs()), ToRegister(lir->rhs()))
+
+template <typename... ArgTypes>
+class ArgSeq {
+  mozilla::Tuple<std::remove_reference_t<ArgTypes>...> args_;
+
+  template <std::size_t... ISeq>
+  inline void generate(CodeGenerator* codegen,
+                       std::index_sequence<ISeq...>) const {
+    // Arguments are pushed in reverse order, from last argument to first
+    // argument.
+    (codegen->pushArg(mozilla::Get<sizeof...(ISeq) - 1 - ISeq>(args_)), ...);
+  }
+
+ public:
+  explicit ArgSeq(ArgTypes&&... args)
+      : args_(std::forward<ArgTypes>(args)...) {}
+
+  inline void generate(CodeGenerator* codegen) const {
+    generate(codegen, std::index_sequence_for<ArgTypes...>{});
+  }
+
+#ifdef DEBUG
+  static constexpr size_t numArgs = sizeof...(ArgTypes);
+#endif
+};
+
+template <typename... ArgTypes>
+inline ArgSeq<ArgTypes...> ArgList(ArgTypes&&... args) {
+  return ArgSeq<ArgTypes...>(std::forward<ArgTypes>(args)...);
+}
+
+// Store wrappers, to generate the right move of data after the VM call.
+
+struct StoreNothing {
+  inline void generate(CodeGenerator* codegen) const {}
+  inline LiveRegisterSet clobbered() const {
+    return LiveRegisterSet();  // No register gets clobbered
+  }
+};
+
+class StoreRegisterTo {
+ private:
+  Register out_;
+
+ public:
+  explicit StoreRegisterTo(Register out) : out_(out) {}
+
+  inline void generate(CodeGenerator* codegen) const {
+    // It's okay to use storePointerResultTo here - the VMFunction wrapper
+    // ensures the upper bytes are zero for bool/int32 return values.
+    codegen->storePointerResultTo(out_);
+  }
+  inline LiveRegisterSet clobbered() const {
+    LiveRegisterSet set;
+    set.add(out_);
+    return set;
+  }
+};
+
+class StoreFloatRegisterTo {
+ private:
+  FloatRegister out_;
+
+ public:
+  explicit StoreFloatRegisterTo(FloatRegister out) : out_(out) {}
+
+  inline void generate(CodeGenerator* codegen) const {
+    codegen->storeFloatResultTo(out_);
+  }
+  inline LiveRegisterSet clobbered() const {
+    LiveRegisterSet set;
+    set.add(out_);
+    return set;
+  }
+};
+
+template <typename Output>
+class StoreValueTo_ {
+ private:
+  Output out_;
+
+ public:
+  explicit StoreValueTo_(const Output& out) : out_(out) {}
+
+  inline void generate(CodeGenerator* codegen) const {
+    codegen->storeResultValueTo(out_);
+  }
+  inline LiveRegisterSet clobbered() const {
+    LiveRegisterSet set;
+    set.add(out_);
+    return set;
+  }
+};
+
+template <typename Output>
+StoreValueTo_<Output> StoreValueTo(const Output& out) {
+  return StoreValueTo_<Output>(out);
+}
+
+template <typename Fn, Fn fn, class ArgSeq, class StoreOutputTo>
+class OutOfLineCallVM : public OutOfLineCodeBase<CodeGenerator> {
+ private:
+  LInstruction* lir_;
+  ArgSeq args_;
+  StoreOutputTo out_;
+
+ public:
+  OutOfLineCallVM(LInstruction* lir, const ArgSeq& args,
+                  const StoreOutputTo& out)
+      : lir_(lir), args_(args), out_(out) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineCallVM(this);
+  }
+
+  LInstruction* lir() const { return lir_; }
+  const ArgSeq& args() const { return args_; }
+  const StoreOutputTo& out() const { return out_; }
+};
+
+template <typename Fn, Fn fn, class ArgSeq, class StoreOutputTo>
+OutOfLineCode* CodeGenerator::oolCallVM(LInstruction* lir, const ArgSeq& args,
+                                        const StoreOutputTo& out) {
+  MOZ_ASSERT(lir->mirRaw());
+  MOZ_ASSERT(lir->mirRaw()->isInstruction());
+
+#ifdef DEBUG
+  VMFunctionId id = VMFunctionToId<Fn, fn>::id;
+  const VMFunctionData& fun = GetVMFunction(id);
+  MOZ_ASSERT(fun.explicitArgs == args.numArgs);
+  MOZ_ASSERT(fun.returnsData() !=
+             (std::is_same_v<StoreOutputTo, StoreNothing>));
+#endif
+
+  OutOfLineCode* ool = new (alloc())
+      OutOfLineCallVM<Fn, fn, ArgSeq, StoreOutputTo>(lir, args, out);
+  addOutOfLineCode(ool, lir->mirRaw()->toInstruction());
+  return ool;
+}
+
+template <typename Fn, Fn fn, class ArgSeq, class StoreOutputTo>
+void CodeGenerator::visitOutOfLineCallVM(
+    OutOfLineCallVM<Fn, fn, ArgSeq, StoreOutputTo>* ool) {
+  LInstruction* lir = ool->lir();
+
+  saveLive(lir);
+  ool->args().generate(this);
+  callVM<Fn, fn>(lir);
+  ool->out().generate(this);
+  restoreLiveIgnore(lir, ool->out().clobbered());
+  masm.jump(ool->rejoin());
+}
+
+class OutOfLineICFallback : public OutOfLineCodeBase<CodeGenerator> {
+ private:
+  LInstruction* lir_;
+  size_t cacheIndex_;
+  size_t cacheInfoIndex_;
+
+ public:
+  OutOfLineICFallback(LInstruction* lir, size_t cacheIndex,
+                      size_t cacheInfoIndex)
+      : lir_(lir), cacheIndex_(cacheIndex), cacheInfoIndex_(cacheInfoIndex) {}
+
+  void bind(MacroAssembler* masm) override {
+    // The binding of the initial jump is done in
+    // CodeGenerator::visitOutOfLineICFallback.
+  }
+
+  size_t cacheIndex() const { return cacheIndex_; }
+  size_t cacheInfoIndex() const { return cacheInfoIndex_; }
+  LInstruction* lir() const { return lir_; }
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineICFallback(this);
+  }
+};
+
+void CodeGeneratorShared::addIC(LInstruction* lir, size_t cacheIndex) {
+  if (cacheIndex == SIZE_MAX) {
+    masm.setOOM();
+    return;
+  }
+
+  DataPtr<IonIC> cache(this, cacheIndex);
+  MInstruction* mir = lir->mirRaw()->toInstruction();
+  cache->setScriptedLocation(mir->block()->info().script(),
+                             mir->resumePoint()->pc());
+
+  Register temp = cache->scratchRegisterForEntryJump();
+  icInfo_.back().icOffsetForJump = masm.movWithPatch(ImmWord(-1), temp);
+  masm.jump(Address(temp, 0));
+
+  MOZ_ASSERT(!icInfo_.empty());
+
+  OutOfLineICFallback* ool =
+      new (alloc()) OutOfLineICFallback(lir, cacheIndex, icInfo_.length() - 1);
+  addOutOfLineCode(ool, mir);
+
+  masm.bind(ool->rejoin());
+  cache->setRejoinOffset(CodeOffset(ool->rejoin()->offset()));
+}
+
+void CodeGenerator::visitOutOfLineICFallback(OutOfLineICFallback* ool) {
+  LInstruction* lir = ool->lir();
+  size_t cacheIndex = ool->cacheIndex();
+  size_t cacheInfoIndex = ool->cacheInfoIndex();
+
+  DataPtr<IonIC> ic(this, cacheIndex);
+
+  // Register the location of the OOL path in the IC.
+  ic->setFallbackOffset(CodeOffset(masm.currentOffset()));
+
+  switch (ic->kind()) {
+    case CacheKind::GetProp:
+    case CacheKind::GetElem: {
+      IonGetPropertyIC* getPropIC = ic->asGetPropertyIC();
+
+      saveLive(lir);
+
+      pushArg(getPropIC->id());
+      pushArg(getPropIC->value());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonGetPropertyIC*,
+                          HandleValue, HandleValue, MutableHandleValue);
+      callVM<Fn, IonGetPropertyIC::update>(lir);
+
+      StoreValueTo(getPropIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreValueTo(getPropIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::GetPropSuper:
+    case CacheKind::GetElemSuper: {
+      IonGetPropSuperIC* getPropSuperIC = ic->asGetPropSuperIC();
+
+      saveLive(lir);
+
+      pushArg(getPropSuperIC->id());
+      pushArg(getPropSuperIC->receiver());
+      pushArg(getPropSuperIC->object());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn =
+          bool (*)(JSContext*, HandleScript, IonGetPropSuperIC*, HandleObject,
+                   HandleValue, HandleValue, MutableHandleValue);
+      callVM<Fn, IonGetPropSuperIC::update>(lir);
+
+      StoreValueTo(getPropSuperIC->output()).generate(this);
+      restoreLiveIgnore(lir,
+                        StoreValueTo(getPropSuperIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::SetProp:
+    case CacheKind::SetElem: {
+      IonSetPropertyIC* setPropIC = ic->asSetPropertyIC();
+
+      saveLive(lir);
+
+      pushArg(setPropIC->rhs());
+      pushArg(setPropIC->id());
+      pushArg(setPropIC->object());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonSetPropertyIC*,
+                          HandleObject, HandleValue, HandleValue);
+      callVM<Fn, IonSetPropertyIC::update>(lir);
+
+      restoreLive(lir);
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::GetName: {
+      IonGetNameIC* getNameIC = ic->asGetNameIC();
+
+      saveLive(lir);
+
+      pushArg(getNameIC->environment());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonGetNameIC*, HandleObject,
+                          MutableHandleValue);
+      callVM<Fn, IonGetNameIC::update>(lir);
+
+      StoreValueTo(getNameIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreValueTo(getNameIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::BindName: {
+      IonBindNameIC* bindNameIC = ic->asBindNameIC();
+
+      saveLive(lir);
+
+      pushArg(bindNameIC->environment());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn =
+          JSObject* (*)(JSContext*, HandleScript, IonBindNameIC*, HandleObject);
+      callVM<Fn, IonBindNameIC::update>(lir);
+
+      StoreRegisterTo(bindNameIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreRegisterTo(bindNameIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::GetIterator: {
+      IonGetIteratorIC* getIteratorIC = ic->asGetIteratorIC();
+
+      saveLive(lir);
+
+      pushArg(getIteratorIC->value());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = JSObject* (*)(JSContext*, HandleScript, IonGetIteratorIC*,
+                               HandleValue);
+      callVM<Fn, IonGetIteratorIC::update>(lir);
+
+      StoreRegisterTo(getIteratorIC->output()).generate(this);
+      restoreLiveIgnore(lir,
+                        StoreRegisterTo(getIteratorIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::OptimizeSpreadCall: {
+      auto* optimizeSpreadCallIC = ic->asOptimizeSpreadCallIC();
+
+      saveLive(lir);
+
+      pushArg(optimizeSpreadCallIC->value());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonOptimizeSpreadCallIC*,
+                          HandleValue, bool*);
+      callVM<Fn, IonOptimizeSpreadCallIC::update>(lir);
+
+      StoreRegisterTo(optimizeSpreadCallIC->output()).generate(this);
+      restoreLiveIgnore(
+          lir, StoreRegisterTo(optimizeSpreadCallIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::In: {
+      IonInIC* inIC = ic->asInIC();
+
+      saveLive(lir);
+
+      pushArg(inIC->object());
+      pushArg(inIC->key());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonInIC*, HandleValue,
+                          HandleObject, bool*);
+      callVM<Fn, IonInIC::update>(lir);
+
+      StoreRegisterTo(inIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreRegisterTo(inIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::HasOwn: {
+      IonHasOwnIC* hasOwnIC = ic->asHasOwnIC();
+
+      saveLive(lir);
+
+      pushArg(hasOwnIC->id());
+      pushArg(hasOwnIC->value());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonHasOwnIC*, HandleValue,
+                          HandleValue, int32_t*);
+      callVM<Fn, IonHasOwnIC::update>(lir);
+
+      StoreRegisterTo(hasOwnIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreRegisterTo(hasOwnIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::CheckPrivateField: {
+      IonCheckPrivateFieldIC* checkPrivateFieldIC = ic->asCheckPrivateFieldIC();
+
+      saveLive(lir);
+
+      pushArg(checkPrivateFieldIC->id());
+      pushArg(checkPrivateFieldIC->value());
+
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonCheckPrivateFieldIC*,
+                          HandleValue, HandleValue, bool*);
+      callVM<Fn, IonCheckPrivateFieldIC::update>(lir);
+
+      StoreRegisterTo(checkPrivateFieldIC->output()).generate(this);
+      restoreLiveIgnore(
+          lir, StoreRegisterTo(checkPrivateFieldIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::InstanceOf: {
+      IonInstanceOfIC* hasInstanceOfIC = ic->asInstanceOfIC();
+
+      saveLive(lir);
+
+      pushArg(hasInstanceOfIC->rhs());
+      pushArg(hasInstanceOfIC->lhs());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext*, HandleScript, IonInstanceOfIC*,
+                          HandleValue lhs, HandleObject rhs, bool* res);
+      callVM<Fn, IonInstanceOfIC::update>(lir);
+
+      StoreRegisterTo(hasInstanceOfIC->output()).generate(this);
+      restoreLiveIgnore(lir,
+                        StoreRegisterTo(hasInstanceOfIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::UnaryArith: {
+      IonUnaryArithIC* unaryArithIC = ic->asUnaryArithIC();
+
+      saveLive(lir);
+
+      pushArg(unaryArithIC->input());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext * cx, HandleScript outerScript,
+                          IonUnaryArithIC * stub, HandleValue val,
+                          MutableHandleValue res);
+      callVM<Fn, IonUnaryArithIC::update>(lir);
+
+      StoreValueTo(unaryArithIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreValueTo(unaryArithIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::ToPropertyKey: {
+      IonToPropertyKeyIC* toPropertyKeyIC = ic->asToPropertyKeyIC();
+
+      saveLive(lir);
+
+      pushArg(toPropertyKeyIC->input());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext * cx, HandleScript outerScript,
+                          IonToPropertyKeyIC * ic, HandleValue val,
+                          MutableHandleValue res);
+      callVM<Fn, IonToPropertyKeyIC::update>(lir);
+
+      StoreValueTo(toPropertyKeyIC->output()).generate(this);
+      restoreLiveIgnore(lir,
+                        StoreValueTo(toPropertyKeyIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::BinaryArith: {
+      IonBinaryArithIC* binaryArithIC = ic->asBinaryArithIC();
+
+      saveLive(lir);
+
+      pushArg(binaryArithIC->rhs());
+      pushArg(binaryArithIC->lhs());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext * cx, HandleScript outerScript,
+                          IonBinaryArithIC * stub, HandleValue lhs,
+                          HandleValue rhs, MutableHandleValue res);
+      callVM<Fn, IonBinaryArithIC::update>(lir);
+
+      StoreValueTo(binaryArithIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreValueTo(binaryArithIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::Compare: {
+      IonCompareIC* compareIC = ic->asCompareIC();
+
+      saveLive(lir);
+
+      pushArg(compareIC->rhs());
+      pushArg(compareIC->lhs());
+      icInfo_[cacheInfoIndex].icOffsetForPush = pushArgWithPatch(ImmWord(-1));
+      pushArg(ImmGCPtr(gen->outerInfo().script()));
+
+      using Fn = bool (*)(JSContext * cx, HandleScript outerScript,
+                          IonCompareIC * stub, HandleValue lhs, HandleValue rhs,
+                          bool* res);
+      callVM<Fn, IonCompareIC::update>(lir);
+
+      StoreRegisterTo(compareIC->output()).generate(this);
+      restoreLiveIgnore(lir, StoreRegisterTo(compareIC->output()).clobbered());
+
+      masm.jump(ool->rejoin());
+      return;
+    }
+    case CacheKind::Call:
+    case CacheKind::TypeOf:
+    case CacheKind::ToBool:
+    case CacheKind::GetIntrinsic:
+    case CacheKind::NewObject:
+      MOZ_CRASH("Unsupported IC");
+  }
+  MOZ_CRASH();
+}
+
+StringObject* MNewStringObject::templateObj() const {
+  return &templateObj_->as<StringObject>();
+}
+
+CodeGenerator::CodeGenerator(MIRGenerator* gen, LIRGraph* graph,
+                             MacroAssembler* masm)
+    : CodeGeneratorSpecific(gen, graph, masm),
+      ionScriptLabels_(gen->alloc()),
+      ionNurseryObjectLabels_(gen->alloc()),
+      scriptCounts_(nullptr),
+      realmStubsToReadBarrier_(0) {}
+
+CodeGenerator::~CodeGenerator() { js_delete(scriptCounts_); }
+
+class OutOfLineZeroIfNaN : public OutOfLineCodeBase<CodeGenerator> {
+  LInstruction* lir_;
+  FloatRegister input_;
+  Register output_;
+
+ public:
+  OutOfLineZeroIfNaN(LInstruction* lir, FloatRegister input, Register output)
+      : lir_(lir), input_(input), output_(output) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineZeroIfNaN(this);
+  }
+  LInstruction* lir() const { return lir_; }
+  FloatRegister input() const { return input_; }
+  Register output() const { return output_; }
+};
+
+void CodeGenerator::visitValueToInt32(LValueToInt32* lir) {
+  ValueOperand operand = ToValue(lir, LValueToInt32::Input);
+  Register output = ToRegister(lir->output());
+  FloatRegister temp = ToFloatRegister(lir->tempFloat());
+
+  Label fails;
+  if (lir->mode() == LValueToInt32::TRUNCATE) {
+    OutOfLineCode* oolDouble = oolTruncateDouble(temp, output, lir->mir());
+
+    // We can only handle strings in truncation contexts, like bitwise
+    // operations.
+    Register stringReg = ToRegister(lir->temp());
+    using Fn = bool (*)(JSContext*, JSString*, double*);
+    auto* oolString = oolCallVM<Fn, StringToNumber>(lir, ArgList(stringReg),
+                                                    StoreFloatRegisterTo(temp));
+    Label* stringEntry = oolString->entry();
+    Label* stringRejoin = oolString->rejoin();
+
+    masm.truncateValueToInt32(operand, stringEntry, stringRejoin,
+                              oolDouble->entry(), stringReg, temp, output,
+                              &fails);
+    masm.bind(oolDouble->rejoin());
+  } else if (lir->mode() == LValueToInt32::TRUNCATE_NOWRAP) {
+    auto* ool = new (alloc()) OutOfLineZeroIfNaN(lir, temp, output);
+    addOutOfLineCode(ool, lir->mir());
+
+    masm.truncateNoWrapValueToInt32(operand, temp, output, ool->entry(),
+                                    &fails);
+    masm.bind(ool->rejoin());
+  } else {
+    masm.convertValueToInt32(operand, temp, output, &fails,
+                             lir->mirNormal()->needsNegativeZeroCheck(),
+                             lir->mirNormal()->conversion());
+  }
+
+  bailoutFrom(&fails, lir->snapshot());
+}
+
+void CodeGenerator::visitOutOfLineZeroIfNaN(OutOfLineZeroIfNaN* ool) {
+  FloatRegister input = ool->input();
+  Register output = ool->output();
+
+  // NaN triggers the failure path for branchTruncateDoubleToInt32() on x86,
+  // x64, and ARM64, so handle it here. In all other cases bail out.
+
+  Label fails;
+  if (input.isSingle()) {
+    masm.branchFloat(Assembler::DoubleOrdered, input, input, &fails);
+  } else {
+    masm.branchDouble(Assembler::DoubleOrdered, input, input, &fails);
+  }
+
+  // ToInteger(NaN) is 0.
+  masm.move32(Imm32(0), output);
+  masm.jump(ool->rejoin());
+
+  bailoutFrom(&fails, ool->lir()->snapshot());
+}
+
+void CodeGenerator::visitValueToDouble(LValueToDouble* lir) {
+  ValueOperand operand = ToValue(lir, LValueToDouble::Input);
+  FloatRegister output = ToFloatRegister(lir->output());
+
+  // Set if we can handle other primitives beside strings, as long as they're
+  // guaranteed to never throw. This rules out symbols and BigInts, but allows
+  // booleans, undefined, and null.
+  bool hasNonStringPrimitives =
+      lir->mir()->conversion() == MToFPInstruction::NonStringPrimitives;
+
+  Label isDouble, isInt32, isBool, isNull, isUndefined, done;
+
+  {
+    ScratchTagScope tag(masm, operand);
+    masm.splitTagForTest(operand, tag);
+
+    masm.branchTestDouble(Assembler::Equal, tag, &isDouble);
+    masm.branchTestInt32(Assembler::Equal, tag, &isInt32);
+
+    if (hasNonStringPrimitives) {
+      masm.branchTestBoolean(Assembler::Equal, tag, &isBool);
+      masm.branchTestUndefined(Assembler::Equal, tag, &isUndefined);
+      masm.branchTestNull(Assembler::Equal, tag, &isNull);
+    }
+  }
+
+  bailout(lir->snapshot());
+
+  if (hasNonStringPrimitives) {
+    masm.bind(&isNull);
+    masm.loadConstantDouble(0.0, output);
+    masm.jump(&done);
+  }
+
+  if (hasNonStringPrimitives) {
+    masm.bind(&isUndefined);
+    masm.loadConstantDouble(GenericNaN(), output);
+    masm.jump(&done);
+  }
+
+  if (hasNonStringPrimitives) {
+    masm.bind(&isBool);
+    masm.boolValueToDouble(operand, output);
+    masm.jump(&done);
+  }
+
+  masm.bind(&isInt32);
+  masm.int32ValueToDouble(operand, output);
+  masm.jump(&done);
+
+  masm.bind(&isDouble);
+  masm.unboxDouble(operand, output);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitValueToFloat32(LValueToFloat32* lir) {
+  ValueOperand operand = ToValue(lir, LValueToFloat32::Input);
+  FloatRegister output = ToFloatRegister(lir->output());
+
+  // Set if we can handle other primitives beside strings, as long as they're
+  // guaranteed to never throw. This rules out symbols and BigInts, but allows
+  // booleans, undefined, and null.
+  bool hasNonStringPrimitives =
+      lir->mir()->conversion() == MToFPInstruction::NonStringPrimitives;
+
+  Label isDouble, isInt32, isBool, isNull, isUndefined, done;
+
+  {
+    ScratchTagScope tag(masm, operand);
+    masm.splitTagForTest(operand, tag);
+
+    masm.branchTestDouble(Assembler::Equal, tag, &isDouble);
+    masm.branchTestInt32(Assembler::Equal, tag, &isInt32);
+
+    if (hasNonStringPrimitives) {
+      masm.branchTestBoolean(Assembler::Equal, tag, &isBool);
+      masm.branchTestUndefined(Assembler::Equal, tag, &isUndefined);
+      masm.branchTestNull(Assembler::Equal, tag, &isNull);
+    }
+  }
+
+  bailout(lir->snapshot());
+
+  if (hasNonStringPrimitives) {
+    masm.bind(&isNull);
+    masm.loadConstantFloat32(0.0f, output);
+    masm.jump(&done);
+  }
+
+  if (hasNonStringPrimitives) {
+    masm.bind(&isUndefined);
+    masm.loadConstantFloat32(float(GenericNaN()), output);
+    masm.jump(&done);
+  }
+
+  if (hasNonStringPrimitives) {
+    masm.bind(&isBool);
+    masm.boolValueToFloat32(operand, output);
+    masm.jump(&done);
+  }
+
+  masm.bind(&isInt32);
+  masm.int32ValueToFloat32(operand, output);
+  masm.jump(&done);
+
+  masm.bind(&isDouble);
+  // ARM and MIPS may not have a double register available if we've
+  // allocated output as a float32.
+#if defined(JS_CODEGEN_ARM) || defined(JS_CODEGEN_MIPS32)
+  ScratchDoubleScope fpscratch(masm);
+  masm.unboxDouble(operand, fpscratch);
+  masm.convertDoubleToFloat32(fpscratch, output);
+#else
+  masm.unboxDouble(operand, output);
+  masm.convertDoubleToFloat32(output, output);
+#endif
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitValueToBigInt(LValueToBigInt* lir) {
+  ValueOperand operand = ToValue(lir, LValueToBigInt::Input);
+  Register output = ToRegister(lir->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleValue);
+  auto* ool =
+      oolCallVM<Fn, ToBigInt>(lir, ArgList(operand), StoreRegisterTo(output));
+
+  Register tag = masm.extractTag(operand, output);
+
+  Label notBigInt, done;
+  masm.branchTestBigInt(Assembler::NotEqual, tag, &notBigInt);
+  masm.unboxBigInt(operand, output);
+  masm.jump(&done);
+  masm.bind(&notBigInt);
+
+  masm.branchTestBoolean(Assembler::Equal, tag, ool->entry());
+  masm.branchTestString(Assembler::Equal, tag, ool->entry());
+
+  // ToBigInt(object) can have side-effects; all other types throw a TypeError.
+  bailout(lir->snapshot());
+
+  masm.bind(ool->rejoin());
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitInt32ToDouble(LInt32ToDouble* lir) {
+  masm.convertInt32ToDouble(ToRegister(lir->input()),
+                            ToFloatRegister(lir->output()));
+}
+
+void CodeGenerator::visitFloat32ToDouble(LFloat32ToDouble* lir) {
+  masm.convertFloat32ToDouble(ToFloatRegister(lir->input()),
+                              ToFloatRegister(lir->output()));
+}
+
+void CodeGenerator::visitDoubleToFloat32(LDoubleToFloat32* lir) {
+  masm.convertDoubleToFloat32(ToFloatRegister(lir->input()),
+                              ToFloatRegister(lir->output()));
+}
+
+void CodeGenerator::visitInt32ToFloat32(LInt32ToFloat32* lir) {
+  masm.convertInt32ToFloat32(ToRegister(lir->input()),
+                             ToFloatRegister(lir->output()));
+}
+
+void CodeGenerator::visitDoubleToInt32(LDoubleToInt32* lir) {
+  Label fail;
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+  masm.convertDoubleToInt32(input, output, &fail,
+                            lir->mir()->needsNegativeZeroCheck());
+  bailoutFrom(&fail, lir->snapshot());
+}
+
+void CodeGenerator::visitFloat32ToInt32(LFloat32ToInt32* lir) {
+  Label fail;
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+  masm.convertFloat32ToInt32(input, output, &fail,
+                             lir->mir()->needsNegativeZeroCheck());
+  bailoutFrom(&fail, lir->snapshot());
+}
+
+void CodeGenerator::visitDoubleToIntegerInt32(LDoubleToIntegerInt32* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  auto* ool = new (alloc()) OutOfLineZeroIfNaN(lir, input, output);
+  addOutOfLineCode(ool, lir->mir());
+
+  masm.branchTruncateDoubleToInt32(input, output, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitFloat32ToIntegerInt32(LFloat32ToIntegerInt32* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  auto* ool = new (alloc()) OutOfLineZeroIfNaN(lir, input, output);
+  addOutOfLineCode(ool, lir->mir());
+
+  masm.branchTruncateFloat32ToInt32(input, output, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::emitOOLTestObject(Register objreg,
+                                      Label* ifEmulatesUndefined,
+                                      Label* ifDoesntEmulateUndefined,
+                                      Register scratch) {
+  saveVolatile(scratch);
+  using Fn = bool (*)(JSObject * obj);
+  masm.setupUnalignedABICall(scratch);
+  masm.passABIArg(objreg);
+  masm.callWithABI<Fn, js::EmulatesUndefined>();
+  masm.storeCallBoolResult(scratch);
+  restoreVolatile(scratch);
+
+  masm.branchIfTrueBool(scratch, ifEmulatesUndefined);
+  masm.jump(ifDoesntEmulateUndefined);
+}
+
+// Base out-of-line code generator for all tests of the truthiness of an
+// object, where the object might not be truthy.  (Recall that per spec all
+// objects are truthy, but we implement the JSCLASS_EMULATES_UNDEFINED class
+// flag to permit objects to look like |undefined| in certain contexts,
+// including in object truthiness testing.)  We check truthiness inline except
+// when we're testing it on a proxy (or if TI guarantees us that the specified
+// object will never emulate |undefined|), in which case out-of-line code will
+// call EmulatesUndefined for a conclusive answer.
+class OutOfLineTestObject : public OutOfLineCodeBase<CodeGenerator> {
+  Register objreg_;
+  Register scratch_;
+
+  Label* ifEmulatesUndefined_;
+  Label* ifDoesntEmulateUndefined_;
+
+#ifdef DEBUG
+  bool initialized() { return ifEmulatesUndefined_ != nullptr; }
+#endif
+
+ public:
+  OutOfLineTestObject()
+      : ifEmulatesUndefined_(nullptr), ifDoesntEmulateUndefined_(nullptr) {}
+
+  void accept(CodeGenerator* codegen) final {
+    MOZ_ASSERT(initialized());
+    codegen->emitOOLTestObject(objreg_, ifEmulatesUndefined_,
+                               ifDoesntEmulateUndefined_, scratch_);
+  }
+
+  // Specify the register where the object to be tested is found, labels to
+  // jump to if the object is truthy or falsy, and a scratch register for
+  // use in the out-of-line path.
+  void setInputAndTargets(Register objreg, Label* ifEmulatesUndefined,
+                          Label* ifDoesntEmulateUndefined, Register scratch) {
+    MOZ_ASSERT(!initialized());
+    MOZ_ASSERT(ifEmulatesUndefined);
+    objreg_ = objreg;
+    scratch_ = scratch;
+    ifEmulatesUndefined_ = ifEmulatesUndefined;
+    ifDoesntEmulateUndefined_ = ifDoesntEmulateUndefined;
+  }
+};
+
+// A subclass of OutOfLineTestObject containing two extra labels, for use when
+// the ifTruthy/ifFalsy labels are needed in inline code as well as out-of-line
+// code.  The user should bind these labels in inline code, and specify them as
+// targets via setInputAndTargets, as appropriate.
+class OutOfLineTestObjectWithLabels : public OutOfLineTestObject {
+  Label label1_;
+  Label label2_;
+
+ public:
+  OutOfLineTestObjectWithLabels() = default;
+
+  Label* label1() { return &label1_; }
+  Label* label2() { return &label2_; }
+};
+
+void CodeGenerator::testObjectEmulatesUndefinedKernel(
+    Register objreg, Label* ifEmulatesUndefined,
+    Label* ifDoesntEmulateUndefined, Register scratch,
+    OutOfLineTestObject* ool) {
+  ool->setInputAndTargets(objreg, ifEmulatesUndefined, ifDoesntEmulateUndefined,
+                          scratch);
+
+  // Perform a fast-path check of the object's class flags if the object's
+  // not a proxy.  Let out-of-line code handle the slow cases that require
+  // saving registers, making a function call, and restoring registers.
+  masm.branchIfObjectEmulatesUndefined(objreg, scratch, ool->entry(),
+                                       ifEmulatesUndefined);
+}
+
+void CodeGenerator::branchTestObjectEmulatesUndefined(
+    Register objreg, Label* ifEmulatesUndefined,
+    Label* ifDoesntEmulateUndefined, Register scratch,
+    OutOfLineTestObject* ool) {
+  MOZ_ASSERT(!ifDoesntEmulateUndefined->bound(),
+             "ifDoesntEmulateUndefined will be bound to the fallthrough path");
+
+  testObjectEmulatesUndefinedKernel(objreg, ifEmulatesUndefined,
+                                    ifDoesntEmulateUndefined, scratch, ool);
+  masm.bind(ifDoesntEmulateUndefined);
+}
+
+void CodeGenerator::testObjectEmulatesUndefined(Register objreg,
+                                                Label* ifEmulatesUndefined,
+                                                Label* ifDoesntEmulateUndefined,
+                                                Register scratch,
+                                                OutOfLineTestObject* ool) {
+  testObjectEmulatesUndefinedKernel(objreg, ifEmulatesUndefined,
+                                    ifDoesntEmulateUndefined, scratch, ool);
+  masm.jump(ifDoesntEmulateUndefined);
+}
+
+void CodeGenerator::testValueTruthyKernel(
+    const ValueOperand& value, const LDefinition* scratch1,
+    const LDefinition* scratch2, FloatRegister fr, Label* ifTruthy,
+    Label* ifFalsy, OutOfLineTestObject* ool, MDefinition* valueMIR) {
+  ScratchTagScope tag(masm, value);
+  masm.splitTagForTest(value, tag);
+
+  masm.branchTestUndefined(Assembler::Equal, tag, ifFalsy);
+  masm.branchTestNull(Assembler::Equal, tag, ifFalsy);
+
+  Label notBoolean;
+  masm.branchTestBoolean(Assembler::NotEqual, tag, &notBoolean);
+  {
+    ScratchTagScopeRelease _(&tag);
+    masm.branchTestBooleanTruthy(false, value, ifFalsy);
+  }
+  masm.jump(ifTruthy);
+  masm.bind(&notBoolean);
+
+  Label notInt32;
+  masm.branchTestInt32(Assembler::NotEqual, tag, &notInt32);
+  {
+    ScratchTagScopeRelease _(&tag);
+    masm.branchTestInt32Truthy(false, value, ifFalsy);
+  }
+  masm.jump(ifTruthy);
+  masm.bind(&notInt32);
+
+  if (ool) {
+    Label notObject;
+    masm.branchTestObject(Assembler::NotEqual, tag, &notObject);
+
+    {
+      ScratchTagScopeRelease _(&tag);
+      Register objreg = masm.extractObject(value, ToRegister(scratch1));
+      testObjectEmulatesUndefined(objreg, ifFalsy, ifTruthy,
+                                  ToRegister(scratch2), ool);
+    }
+
+    masm.bind(&notObject);
+  } else {
+    masm.branchTestObject(Assembler::Equal, tag, ifTruthy);
+  }
+
+  Label notString;
+  masm.branchTestString(Assembler::NotEqual, tag, &notString);
+  {
+    ScratchTagScopeRelease _(&tag);
+    masm.branchTestStringTruthy(false, value, ifFalsy);
+  }
+  masm.jump(ifTruthy);
+  masm.bind(&notString);
+
+  Label notBigInt;
+  masm.branchTestBigInt(Assembler::NotEqual, tag, &notBigInt);
+  {
+    ScratchTagScopeRelease _(&tag);
+    masm.branchTestBigIntTruthy(false, value, ifFalsy);
+  }
+  masm.jump(ifTruthy);
+  masm.bind(&notBigInt);
+
+  // All symbols are truthy.
+  masm.branchTestSymbol(Assembler::Equal, tag, ifTruthy);
+
+  // If we reach here the value is a double.
+#ifdef DEBUG
+  Label isDouble;
+  masm.branchTestDouble(Assembler::Equal, tag, &isDouble);
+  masm.assumeUnreachable("Unexpected Value type in testValueTruthyKernel");
+  masm.bind(&isDouble);
+#endif
+  {
+    ScratchTagScopeRelease _(&tag);
+    masm.unboxDouble(value, fr);
+    masm.branchTestDoubleTruthy(false, fr, ifFalsy);
+  }
+
+  // Fall through for truthy.
+}
+
+void CodeGenerator::testValueTruthy(const ValueOperand& value,
+                                    const LDefinition* scratch1,
+                                    const LDefinition* scratch2,
+                                    FloatRegister fr, Label* ifTruthy,
+                                    Label* ifFalsy, OutOfLineTestObject* ool,
+                                    MDefinition* valueMIR) {
+  testValueTruthyKernel(value, scratch1, scratch2, fr, ifTruthy, ifFalsy, ool,
+                        valueMIR);
+  masm.jump(ifTruthy);
+}
+
+void CodeGenerator::visitTestOAndBranch(LTestOAndBranch* lir) {
+  Label* truthy = getJumpLabelForBranch(lir->ifTruthy());
+  Label* falsy = getJumpLabelForBranch(lir->ifFalsy());
+  Register input = ToRegister(lir->input());
+
+  auto* ool = new (alloc()) OutOfLineTestObject();
+  addOutOfLineCode(ool, lir->mir());
+
+  testObjectEmulatesUndefined(input, falsy, truthy, ToRegister(lir->temp()),
+                              ool);
+}
+
+void CodeGenerator::visitTestVAndBranch(LTestVAndBranch* lir) {
+  MDefinition* input = lir->mir()->input();
+
+  auto* ool = new (alloc()) OutOfLineTestObject();
+  addOutOfLineCode(ool, lir->mir());
+
+  Label* truthy = getJumpLabelForBranch(lir->ifTruthy());
+  Label* falsy = getJumpLabelForBranch(lir->ifFalsy());
+
+  testValueTruthy(ToValue(lir, LTestVAndBranch::Input), lir->temp1(),
+                  lir->temp2(), ToFloatRegister(lir->tempFloat()), truthy,
+                  falsy, ool, input);
+}
+
+void CodeGenerator::visitBooleanToString(LBooleanToString* lir) {
+  Register input = ToRegister(lir->input());
+  Register output = ToRegister(lir->output());
+  const JSAtomState& names = gen->runtime->names();
+  Label true_, done;
+
+  masm.branchTest32(Assembler::NonZero, input, input, &true_);
+  masm.movePtr(ImmGCPtr(names.false_), output);
+  masm.jump(&done);
+
+  masm.bind(&true_);
+  masm.movePtr(ImmGCPtr(names.true_), output);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::emitIntToString(Register input, Register output,
+                                    Label* ool) {
+  masm.boundsCheck32PowerOfTwo(input, StaticStrings::INT_STATIC_LIMIT, ool);
+
+  // Fast path for small integers.
+  masm.movePtr(ImmPtr(&gen->runtime->staticStrings().intStaticTable), output);
+  masm.loadPtr(BaseIndex(output, input, ScalePointer), output);
+}
+
+void CodeGenerator::visitIntToString(LIntToString* lir) {
+  Register input = ToRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  using Fn = JSLinearString* (*)(JSContext*, int);
+  OutOfLineCode* ool = oolCallVM<Fn, Int32ToString<CanGC>>(
+      lir, ArgList(input), StoreRegisterTo(output));
+
+  emitIntToString(input, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitDoubleToString(LDoubleToString* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register temp = ToRegister(lir->tempInt());
+  Register output = ToRegister(lir->output());
+
+  using Fn = JSString* (*)(JSContext*, double);
+  OutOfLineCode* ool = oolCallVM<Fn, NumberToString<CanGC>>(
+      lir, ArgList(input), StoreRegisterTo(output));
+
+  // Try double to integer conversion and run integer to string code.
+  masm.convertDoubleToInt32(input, temp, ool->entry(), false);
+  emitIntToString(temp, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitValueToString(LValueToString* lir) {
+  ValueOperand input = ToValue(lir, LValueToString::Input);
+  Register output = ToRegister(lir->output());
+
+  using Fn = JSString* (*)(JSContext*, HandleValue);
+  OutOfLineCode* ool = oolCallVM<Fn, ToStringSlow<CanGC>>(
+      lir, ArgList(input), StoreRegisterTo(output));
+
+  Label done;
+  Register tag = masm.extractTag(input, output);
+  const JSAtomState& names = gen->runtime->names();
+
+  // String
+  {
+    Label notString;
+    masm.branchTestString(Assembler::NotEqual, tag, &notString);
+    masm.unboxString(input, output);
+    masm.jump(&done);
+    masm.bind(&notString);
+  }
+
+  // Integer
+  {
+    Label notInteger;
+    masm.branchTestInt32(Assembler::NotEqual, tag, &notInteger);
+    Register unboxed = ToTempUnboxRegister(lir->tempToUnbox());
+    unboxed = masm.extractInt32(input, unboxed);
+    emitIntToString(unboxed, output, ool->entry());
+    masm.jump(&done);
+    masm.bind(&notInteger);
+  }
+
+  // Double
+  {
+    // Note: no fastpath. Need two extra registers and can only convert doubles
+    // that fit integers and are smaller than StaticStrings::INT_STATIC_LIMIT.
+    masm.branchTestDouble(Assembler::Equal, tag, ool->entry());
+  }
+
+  // Undefined
+  {
+    Label notUndefined;
+    masm.branchTestUndefined(Assembler::NotEqual, tag, &notUndefined);
+    masm.movePtr(ImmGCPtr(names.undefined), output);
+    masm.jump(&done);
+    masm.bind(&notUndefined);
+  }
+
+  // Null
+  {
+    Label notNull;
+    masm.branchTestNull(Assembler::NotEqual, tag, &notNull);
+    masm.movePtr(ImmGCPtr(names.null), output);
+    masm.jump(&done);
+    masm.bind(&notNull);
+  }
+
+  // Boolean
+  {
+    Label notBoolean, true_;
+    masm.branchTestBoolean(Assembler::NotEqual, tag, &notBoolean);
+    masm.branchTestBooleanTruthy(true, input, &true_);
+    masm.movePtr(ImmGCPtr(names.false_), output);
+    masm.jump(&done);
+    masm.bind(&true_);
+    masm.movePtr(ImmGCPtr(names.true_), output);
+    masm.jump(&done);
+    masm.bind(&notBoolean);
+  }
+
+  // Objects/symbols are only possible when |mir->mightHaveSideEffects()|.
+  if (lir->mir()->mightHaveSideEffects()) {
+    // Object
+    if (lir->mir()->supportSideEffects()) {
+      masm.branchTestObject(Assembler::Equal, tag, ool->entry());
+    } else {
+      // Bail.
+      MOZ_ASSERT(lir->mir()->needsSnapshot());
+      Label bail;
+      masm.branchTestObject(Assembler::Equal, tag, &bail);
+      bailoutFrom(&bail, lir->snapshot());
+    }
+
+    // Symbol
+    if (lir->mir()->supportSideEffects()) {
+      masm.branchTestSymbol(Assembler::Equal, tag, ool->entry());
+    } else {
+      // Bail.
+      MOZ_ASSERT(lir->mir()->needsSnapshot());
+      Label bail;
+      masm.branchTestSymbol(Assembler::Equal, tag, &bail);
+      bailoutFrom(&bail, lir->snapshot());
+    }
+  }
+
+  // BigInt
+  {
+    // No fastpath currently implemented.
+    masm.branchTestBigInt(Assembler::Equal, tag, ool->entry());
+  }
+
+  masm.assumeUnreachable("Unexpected type for LValueToString.");
+
+  masm.bind(&done);
+  masm.bind(ool->rejoin());
+}
+
+using StoreBufferMutationFn = void (*)(js::gc::StoreBuffer*, js::gc::Cell**);
+
+static void EmitStoreBufferMutation(MacroAssembler& masm, Register holder,
+                                    size_t offset, Register buffer,
+                                    LiveGeneralRegisterSet& liveVolatiles,
+                                    StoreBufferMutationFn fun) {
+  Label callVM;
+  Label exit;
+
+  // Call into the VM to barrier the write. The only registers that need to
+  // be preserved are those in liveVolatiles, so once they are saved on the
+  // stack all volatile registers are available for use.
+  masm.bind(&callVM);
+  masm.PushRegsInMask(liveVolatiles);
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::Volatile());
+  regs.takeUnchecked(buffer);
+  regs.takeUnchecked(holder);
+  Register addrReg = regs.takeAny();
+
+  masm.computeEffectiveAddress(Address(holder, offset), addrReg);
+
+  bool needExtraReg = !regs.hasAny<GeneralRegisterSet::DefaultType>();
+  if (needExtraReg) {
+    masm.push(holder);
+    masm.setupUnalignedABICall(holder);
+  } else {
+    masm.setupUnalignedABICall(regs.takeAny());
+  }
+  masm.passABIArg(buffer);
+  masm.passABIArg(addrReg);
+  masm.callWithABI(DynamicFunction<StoreBufferMutationFn>(fun), MoveOp::GENERAL,
+                   CheckUnsafeCallWithABI::DontCheckOther);
+
+  if (needExtraReg) {
+    masm.pop(holder);
+  }
+  masm.PopRegsInMask(liveVolatiles);
+  masm.bind(&exit);
+}
+
+// Warning: this function modifies prev and next.
+static void EmitPostWriteBarrierS(MacroAssembler& masm, Register holder,
+                                  size_t offset, Register prev, Register next,
+                                  LiveGeneralRegisterSet& liveVolatiles) {
+  Label exit;
+  Label checkRemove, putCell;
+
+  // if (next && (buffer = next->storeBuffer()))
+  // but we never pass in nullptr for next.
+  Register storebuffer = next;
+  masm.loadStoreBuffer(next, storebuffer);
+  masm.branchPtr(Assembler::Equal, storebuffer, ImmWord(0), &checkRemove);
+
+  // if (prev && prev->storeBuffer())
+  masm.branchPtr(Assembler::Equal, prev, ImmWord(0), &putCell);
+  masm.loadStoreBuffer(prev, prev);
+  masm.branchPtr(Assembler::NotEqual, prev, ImmWord(0), &exit);
+
+  // buffer->putCell(cellp)
+  masm.bind(&putCell);
+  EmitStoreBufferMutation(masm, holder, offset, storebuffer, liveVolatiles,
+                          JSString::addCellAddressToStoreBuffer);
+  masm.jump(&exit);
+
+  // if (prev && (buffer = prev->storeBuffer()))
+  masm.bind(&checkRemove);
+  masm.branchPtr(Assembler::Equal, prev, ImmWord(0), &exit);
+  masm.loadStoreBuffer(prev, storebuffer);
+  masm.branchPtr(Assembler::Equal, storebuffer, ImmWord(0), &exit);
+  EmitStoreBufferMutation(masm, holder, offset, storebuffer, liveVolatiles,
+                          JSString::removeCellAddressFromStoreBuffer);
+
+  masm.bind(&exit);
+}
+
+void CodeGenerator::visitRegExp(LRegExp* lir) {
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+  JSObject* source = lir->mir()->source();
+
+  using Fn = JSObject* (*)(JSContext*, Handle<RegExpObject*>);
+  OutOfLineCode* ool = oolCallVM<Fn, CloneRegExpObject>(
+      lir, ArgList(ImmGCPtr(source)), StoreRegisterTo(output));
+  if (lir->mir()->hasShared()) {
+    TemplateObject templateObject(source);
+    masm.createGCObject(output, temp, templateObject, gc::DefaultHeap,
+                        ool->entry());
+  } else {
+    masm.jump(ool->entry());
+  }
+  masm.bind(ool->rejoin());
+}
+
+static const size_t InputOutputDataSize = sizeof(irregexp::InputOutputData);
+
+// Amount of space to reserve on the stack when executing RegExps inline.
+static const size_t RegExpReservedStack =
+    InputOutputDataSize + sizeof(MatchPairs) +
+    RegExpObject::MaxPairCount * sizeof(MatchPair);
+
+static size_t RegExpPairsVectorStartOffset(size_t inputOutputDataStartOffset) {
+  return inputOutputDataStartOffset + InputOutputDataSize + sizeof(MatchPairs);
+}
+
+static Address RegExpPairCountAddress(MacroAssembler& masm,
+                                      size_t inputOutputDataStartOffset) {
+  return Address(masm.getStackPointer(), inputOutputDataStartOffset +
+                                             InputOutputDataSize +
+                                             MatchPairs::offsetOfPairCount());
+}
+
+// When the unicode flag is set, if lastIndex points to a trail
+// surrogate, we should step back to the corresponding lead surrogate.
+// See ExecuteRegExp in builtin/RegExp.cpp for more detail.
+static void StepBackToLeadSurrogate(MacroAssembler& masm, Register regexpShared,
+                                    Register input, Register lastIndex,
+                                    Register temp1, Register temp2) {
+  Label done;
+
+  // If the unicode flag is not set, there is nothing to do.
+  masm.branchTest32(Assembler::Zero,
+                    Address(regexpShared, RegExpShared::offsetOfFlags()),
+                    Imm32(int32_t(JS::RegExpFlag::Unicode)), &done);
+
+  // If the input is latin1, there can't be any surrogates.
+  masm.branchLatin1String(input, &done);
+
+  // Check if |lastIndex > 0 && lastIndex < input->length()|.
+  // lastIndex should already have no sign here.
+  masm.branchTest32(Assembler::Zero, lastIndex, lastIndex, &done);
+  masm.loadStringLength(input, temp1);
+  masm.branch32(Assembler::AboveOrEqual, lastIndex, temp1, &done);
+
+  // For TrailSurrogateMin ≤ x ≤ TrailSurrogateMax and
+  // LeadSurrogateMin ≤ x ≤ LeadSurrogateMax, the following
+  // equations hold.
+  //
+  //    SurrogateMin ≤ x ≤ SurrogateMax
+  // <> SurrogateMin ≤ x ≤ SurrogateMin + 2^10 - 1
+  // <> ((x - SurrogateMin) >>> 10) = 0    where >>> is an unsigned-shift
+  // See Hacker's Delight, section 4-1 for details.
+  //
+  //    ((x - SurrogateMin) >>> 10) = 0
+  // <> floor((x - SurrogateMin) / 1024) = 0
+  // <> floor((x / 1024) - (SurrogateMin / 1024)) = 0
+  // <> floor(x / 1024) = SurrogateMin / 1024
+  // <> floor(x / 1024) * 1024 = SurrogateMin
+  // <> (x >>> 10) << 10 = SurrogateMin
+  // <> x & ~(2^10 - 1) = SurrogateMin
+
+  constexpr char16_t SurrogateMask = 0xFC00;
+
+  Register charsReg = temp1;
+  masm.loadStringChars(input, charsReg, CharEncoding::TwoByte);
+
+  // Check if input[lastIndex] is trail surrogate.
+  masm.loadChar(charsReg, lastIndex, temp2, CharEncoding::TwoByte);
+  masm.and32(Imm32(SurrogateMask), temp2);
+  masm.branch32(Assembler::NotEqual, temp2, Imm32(unicode::TrailSurrogateMin),
+                &done);
+
+  // Check if input[lastIndex-1] is lead surrogate.
+  masm.loadChar(charsReg, lastIndex, temp2, CharEncoding::TwoByte,
+                -int32_t(sizeof(char16_t)));
+  masm.and32(Imm32(SurrogateMask), temp2);
+  masm.branch32(Assembler::NotEqual, temp2, Imm32(unicode::LeadSurrogateMin),
+                &done);
+
+  // Move lastIndex back to lead surrogate.
+  masm.sub32(Imm32(1), lastIndex);
+
+  masm.bind(&done);
+}
+
+static void UpdateRegExpStatics(MacroAssembler& masm, Register regexp,
+                                Register input, Register lastIndex,
+                                Register staticsReg, Register temp1,
+                                Register temp2, bool stringsCanBeInNursery,
+                                LiveGeneralRegisterSet& volatileRegs) {
+  Address pendingInputAddress(staticsReg,
+                              RegExpStatics::offsetOfPendingInput());
+  Address matchesInputAddress(staticsReg,
+                              RegExpStatics::offsetOfMatchesInput());
+  Address lazySourceAddress(staticsReg, RegExpStatics::offsetOfLazySource());
+  Address lazyIndexAddress(staticsReg, RegExpStatics::offsetOfLazyIndex());
+
+  masm.guardedCallPreBarrier(pendingInputAddress, MIRType::String);
+  masm.guardedCallPreBarrier(matchesInputAddress, MIRType::String);
+  masm.guardedCallPreBarrier(lazySourceAddress, MIRType::String);
+
+  if (stringsCanBeInNursery) {
+    // Writing into RegExpStatics tenured memory; must post-barrier.
+    if (staticsReg.volatile_()) {
+      volatileRegs.add(staticsReg);
+    }
+
+    masm.loadPtr(pendingInputAddress, temp1);
+    masm.storePtr(input, pendingInputAddress);
+    masm.movePtr(input, temp2);
+    EmitPostWriteBarrierS(masm, staticsReg,
+                          RegExpStatics::offsetOfPendingInput(),
+                          temp1 /* prev */, temp2 /* next */, volatileRegs);
+
+    masm.loadPtr(matchesInputAddress, temp1);
+    masm.storePtr(input, matchesInputAddress);
+    masm.movePtr(input, temp2);
+    EmitPostWriteBarrierS(masm, staticsReg,
+                          RegExpStatics::offsetOfMatchesInput(),
+                          temp1 /* prev */, temp2 /* next */, volatileRegs);
+  } else {
+    masm.storePtr(input, pendingInputAddress);
+    masm.storePtr(input, matchesInputAddress);
+  }
+
+  masm.storePtr(lastIndex,
+                Address(staticsReg, RegExpStatics::offsetOfLazyIndex()));
+  masm.store32(
+      Imm32(1),
+      Address(staticsReg, RegExpStatics::offsetOfPendingLazyEvaluation()));
+
+  masm.unboxNonDouble(Address(regexp, NativeObject::getFixedSlotOffset(
+                                          RegExpObject::SHARED_SLOT)),
+                      temp1, JSVAL_TYPE_PRIVATE_GCTHING);
+  masm.loadPtr(Address(temp1, RegExpShared::offsetOfSource()), temp2);
+  masm.storePtr(temp2, lazySourceAddress);
+  masm.load32(Address(temp1, RegExpShared::offsetOfFlags()), temp2);
+  masm.store32(temp2, Address(staticsReg, RegExpStatics::offsetOfLazyFlags()));
+}
+
+// Prepare an InputOutputData and optional MatchPairs which space has been
+// allocated for on the stack, and try to execute a RegExp on a string input.
+// If the RegExp was successfully executed and matched the input, fallthrough.
+// Otherwise, jump to notFound or failure.
+static bool PrepareAndExecuteRegExp(JSContext* cx, MacroAssembler& masm,
+                                    Register regexp, Register input,
+                                    Register lastIndex, Register temp1,
+                                    Register temp2, Register temp3,
+                                    size_t inputOutputDataStartOffset,
+                                    bool stringsCanBeInNursery, Label* notFound,
+                                    Label* failure) {
+  JitSpew(JitSpew_Codegen, "# Emitting PrepareAndExecuteRegExp");
+
+  using irregexp::InputOutputData;
+
+  /*
+   * [SMDOC] Stack layout for PrepareAndExecuteRegExp
+   *
+   * Before this function is called, the caller is responsible for
+   * allocating enough stack space for the following data:
+   *
+   * inputOutputDataStartOffset +-----> +---------------+
+   *                                    |InputOutputData|
+   *          inputStartAddress +---------->  inputStart|
+   *            inputEndAddress +---------->    inputEnd|
+   *          startIndexAddress +---------->  startIndex|
+   *             matchesAddress +---------->     matches|-----+
+   *                                    +---------------+     |
+   * matchPairs(Address|Offset) +-----> +---------------+  <--+
+   *                                    |  MatchPairs   |
+   *           pairCountAddress +---------->    count   |
+   *        pairsPointerAddress +---------->    pairs   |-----+
+   *                                    +---------------+     |
+   * pairsArray(Address|Offset) +-----> +---------------+  <--+
+   *                                    |   MatchPair   |
+   *     firstMatchStartAddress +---------->    start   |  <--+
+   *                                    |       limit   |     |
+   *                                    +---------------+     |
+   *                                           .              |
+   *                                           .  Reserved space for
+   *                                           .  RegExpObject::MaxPairCount
+   *                                           .  MatchPair objects
+   *                                           .              |
+   *                                    +---------------+     |
+   *                                    |   MatchPair   |     |
+   *                                    |       start   |     |
+   *                                    |       limit   |  <--+
+   *                                    +---------------+
+   */
+
+  size_t ioOffset = inputOutputDataStartOffset;
+  size_t matchPairsOffset = ioOffset + sizeof(InputOutputData);
+  size_t pairsArrayOffset = matchPairsOffset + sizeof(MatchPairs);
+
+  Address inputStartAddress(masm.getStackPointer(),
+                            ioOffset + offsetof(InputOutputData, inputStart));
+  Address inputEndAddress(masm.getStackPointer(),
+                          ioOffset + offsetof(InputOutputData, inputEnd));
+  Address startIndexAddress(masm.getStackPointer(),
+                            ioOffset + offsetof(InputOutputData, startIndex));
+  Address matchesAddress(masm.getStackPointer(),
+                         ioOffset + offsetof(InputOutputData, matches));
+
+  Address matchPairsAddress(masm.getStackPointer(), matchPairsOffset);
+  Address pairCountAddress(masm.getStackPointer(),
+                           matchPairsOffset + MatchPairs::offsetOfPairCount());
+  Address pairsPointerAddress(masm.getStackPointer(),
+                              matchPairsOffset + MatchPairs::offsetOfPairs());
+
+  Address pairsArrayAddress(masm.getStackPointer(), pairsArrayOffset);
+  Address firstMatchStartAddress(masm.getStackPointer(),
+                                 pairsArrayOffset + offsetof(MatchPair, start));
+
+  // First, fill in a skeletal MatchPairs instance on the stack. This will be
+  // passed to the OOL stub in the caller if we aren't able to execute the
+  // RegExp inline, and that stub needs to be able to determine whether the
+  // execution finished successfully.
+
+  // Initialize MatchPairs::pairCount to 1. The correct value can only
+  // be determined after loading the RegExpShared. If the RegExpShared
+  // has Kind::Atom, this is the correct pairCount.
+  masm.store32(Imm32(1), pairCountAddress);
+
+  // Initialize MatchPairs::pairs pointer
+  masm.computeEffectiveAddress(pairsArrayAddress, temp1);
+  masm.storePtr(temp1, pairsPointerAddress);
+
+  // Initialize MatchPairs::pairs[0]::start to MatchPair::NoMatch
+  masm.store32(Imm32(MatchPair::NoMatch), firstMatchStartAddress);
+
+  // Check for a linear input string.
+  masm.branchIfRope(input, failure);
+
+  // Load the RegExpShared.
+  Register regexpReg = temp1;
+  Address sharedSlot = Address(
+      regexp, NativeObject::getFixedSlotOffset(RegExpObject::SHARED_SLOT));
+  masm.branchTestUndefined(Assembler::Equal, sharedSlot, failure);
+  masm.unboxNonDouble(sharedSlot, regexpReg, JSVAL_TYPE_PRIVATE_GCTHING);
+
+  // Handle Atom matches
+  Label notAtom, checkSuccess;
+  masm.branchPtr(Assembler::Equal,
+                 Address(regexpReg, RegExpShared::offsetOfPatternAtom()),
+                 ImmWord(0), &notAtom);
+  {
+    LiveGeneralRegisterSet regsToSave(GeneralRegisterSet::Volatile());
+    regsToSave.takeUnchecked(temp1);
+    regsToSave.takeUnchecked(temp2);
+    regsToSave.takeUnchecked(temp3);
+
+    masm.computeEffectiveAddress(matchPairsAddress, temp3);
+
+    masm.PushRegsInMask(regsToSave);
+    using Fn = RegExpRunStatus (*)(RegExpShared * re, JSLinearString * input,
+                                   size_t start, MatchPairs * matchPairs);
+    masm.setupUnalignedABICall(temp2);
+    masm.passABIArg(regexpReg);
+    masm.passABIArg(input);
+    masm.passABIArg(lastIndex);
+    masm.passABIArg(temp3);
+    masm.callWithABI<Fn, js::ExecuteRegExpAtomRaw>();
+
+    masm.storeCallInt32Result(temp1);
+    masm.PopRegsInMask(regsToSave);
+
+    masm.jump(&checkSuccess);
+  }
+  masm.bind(&notAtom);
+
+  // Don't handle regexps with too many capture pairs.
+  masm.load32(Address(regexpReg, RegExpShared::offsetOfPairCount()), temp2);
+  masm.branch32(Assembler::Above, temp2, Imm32(RegExpObject::MaxPairCount),
+                failure);
+
+  // Fill in the pair count in the MatchPairs on the stack.
+  masm.store32(temp2, pairCountAddress);
+
+  // Update lastIndex if necessary.
+  StepBackToLeadSurrogate(masm, regexpReg, input, lastIndex, temp2, temp3);
+
+  // Load code pointer and length of input (in bytes).
+  // Store the input start in the InputOutputData.
+  Register codePointer = temp1;  // Note: temp1 was previously regexpReg.
+  Register byteLength = temp3;
+  {
+    Label isLatin1, done;
+    masm.loadStringLength(input, byteLength);
+
+    masm.branchLatin1String(input, &isLatin1);
+
+    // Two-byte input
+    masm.loadStringChars(input, temp2, CharEncoding::TwoByte);
+    masm.storePtr(temp2, inputStartAddress);
+    masm.loadPtr(
+        Address(regexpReg, RegExpShared::offsetOfJitCode(/*latin1 =*/false)),
+        codePointer);
+    masm.lshiftPtr(Imm32(1), byteLength);
+    masm.jump(&done);
+
+    // Latin1 input
+    masm.bind(&isLatin1);
+    masm.loadStringChars(input, temp2, CharEncoding::Latin1);
+    masm.storePtr(temp2, inputStartAddress);
+    masm.loadPtr(
+        Address(regexpReg, RegExpShared::offsetOfJitCode(/*latin1 =*/true)),
+        codePointer);
+
+    masm.bind(&done);
+
+    // Store end pointer
+    masm.addPtr(byteLength, temp2);
+    masm.storePtr(temp2, inputEndAddress);
+  }
+
+  // Guard that the RegExpShared has been compiled for this type of input.
+  // If it has not been compiled, we fall back to the OOL case, which will
+  // do a VM call into the interpreter.
+  // TODO: add an interpreter trampoline?
+  masm.branchPtr(Assembler::Equal, codePointer, ImmWord(0), failure);
+  masm.loadPtr(Address(codePointer, JitCode::offsetOfCode()), codePointer);
+
+  // Finish filling in the InputOutputData instance on the stack
+  masm.computeEffectiveAddress(matchPairsAddress, temp2);
+  masm.storePtr(temp2, matchesAddress);
+  masm.storePtr(lastIndex, startIndexAddress);
+
+  // Save any volatile inputs.
+  LiveGeneralRegisterSet volatileRegs;
+  if (lastIndex.volatile_()) {
+    volatileRegs.add(lastIndex);
+  }
+  if (input.volatile_()) {
+    volatileRegs.add(input);
+  }
+  if (regexp.volatile_()) {
+    volatileRegs.add(regexp);
+  }
+
+#ifdef JS_TRACE_LOGGING
+  if (TraceLogTextIdEnabled(TraceLogger_IrregexpExecute)) {
+    masm.loadTraceLogger(temp2);
+    masm.tracelogStartId(temp2, TraceLogger_IrregexpExecute);
+  }
+#endif
+
+  // Execute the RegExp.
+  masm.computeEffectiveAddress(
+      Address(masm.getStackPointer(), inputOutputDataStartOffset), temp2);
+  masm.PushRegsInMask(volatileRegs);
+  masm.setupUnalignedABICall(temp3);
+  masm.passABIArg(temp2);
+  masm.callWithABI(codePointer);
+  masm.storeCallInt32Result(temp1);
+  masm.PopRegsInMask(volatileRegs);
+
+#ifdef JS_TRACE_LOGGING
+  if (TraceLogTextIdEnabled(TraceLogger_IrregexpExecute)) {
+    masm.loadTraceLogger(temp2);
+    masm.tracelogStopId(temp2, TraceLogger_IrregexpExecute);
+  }
+#endif
+
+  Label success;
+  masm.bind(&checkSuccess);
+  masm.branch32(Assembler::Equal, temp1,
+                Imm32(RegExpRunStatus_Success_NotFound), notFound);
+  masm.branch32(Assembler::Equal, temp1, Imm32(RegExpRunStatus_Error), failure);
+
+  // Lazily update the RegExpStatics.
+  RegExpStatics* res = GlobalObject::getRegExpStatics(cx, cx->global());
+  if (!res) {
+    return false;
+  }
+  masm.movePtr(ImmPtr(res), temp1);
+  UpdateRegExpStatics(masm, regexp, input, lastIndex, temp1, temp2, temp3,
+                      stringsCanBeInNursery, volatileRegs);
+
+  return true;
+}
+
+static void CopyStringChars(MacroAssembler& masm, Register to, Register from,
+                            Register len, Register byteOpScratch,
+                            CharEncoding encoding);
+
+class CreateDependentString {
+  CharEncoding encoding_;
+  Register string_;
+  Register temp1_;
+  Register temp2_;
+  Label* failure_;
+
+  enum class FallbackKind : uint8_t {
+    InlineString,
+    FatInlineString,
+    NotInlineString,
+    Count
+  };
+  mozilla::EnumeratedArray<FallbackKind, FallbackKind::Count, Label> fallbacks_,
+      joins_;
+
+ public:
+  CreateDependentString(CharEncoding encoding, Register string, Register temp1,
+                        Register temp2, Label* failure)
+      : encoding_(encoding),
+        string_(string),
+        temp1_(temp1),
+        temp2_(temp2),
+        failure_(failure) {}
+
+  Register string() const { return string_; }
+  CharEncoding encoding() const { return encoding_; }
+
+  // Generate code that creates DependentString.
+  // Caller should call generateFallback after masm.ret(), to generate
+  // fallback path.
+  void generate(MacroAssembler& masm, const JSAtomState& names,
+                CompileRuntime* runtime, Register base,
+                BaseIndex startIndexAddress, BaseIndex limitIndexAddress,
+                bool stringsCanBeInNursery);
+
+  // Generate fallback path for creating DependentString.
+  void generateFallback(MacroAssembler& masm);
+};
+
+void CreateDependentString::generate(MacroAssembler& masm,
+                                     const JSAtomState& names,
+                                     CompileRuntime* runtime, Register base,
+                                     BaseIndex startIndexAddress,
+                                     BaseIndex limitIndexAddress,
+                                     bool stringsCanBeInNursery) {
+  JitSpew(JitSpew_Codegen, "# Emitting CreateDependentString (encoding=%s)",
+          (encoding_ == CharEncoding::Latin1 ? "Latin-1" : "Two-Byte"));
+
+  auto newGCString = [&](FallbackKind kind) {
+    uint32_t flags = kind == FallbackKind::InlineString
+                         ? JSString::INIT_THIN_INLINE_FLAGS
+                     : kind == FallbackKind::FatInlineString
+                         ? JSString::INIT_FAT_INLINE_FLAGS
+                         : JSString::INIT_DEPENDENT_FLAGS;
+    if (encoding_ == CharEncoding::Latin1) {
+      flags |= JSString::LATIN1_CHARS_BIT;
+    }
+
+    if (kind != FallbackKind::FatInlineString) {
+      masm.newGCString(string_, temp2_, &fallbacks_[kind],
+                       stringsCanBeInNursery);
+    } else {
+      masm.newGCFatInlineString(string_, temp2_, &fallbacks_[kind],
+                                stringsCanBeInNursery);
+    }
+    masm.bind(&joins_[kind]);
+    masm.store32(Imm32(flags), Address(string_, JSString::offsetOfFlags()));
+  };
+
+  // Compute the string length.
+  masm.load32(startIndexAddress, temp2_);
+  masm.load32(limitIndexAddress, temp1_);
+  masm.sub32(temp2_, temp1_);
+
+  Label done, nonEmpty;
+
+  // Zero length matches use the empty string.
+  masm.branchTest32(Assembler::NonZero, temp1_, temp1_, &nonEmpty);
+  masm.movePtr(ImmGCPtr(names.empty), string_);
+  masm.jump(&done);
+
+  masm.bind(&nonEmpty);
+
+  // Complete matches use the base string.
+  Label nonBaseStringMatch;
+  masm.branchTest32(Assembler::NonZero, temp2_, temp2_, &nonBaseStringMatch);
+  masm.branch32(Assembler::NotEqual, Address(base, JSString::offsetOfLength()),
+                temp1_, &nonBaseStringMatch);
+  masm.movePtr(base, string_);
+  masm.jump(&done);
+
+  masm.bind(&nonBaseStringMatch);
+
+  Label notInline;
+
+  int32_t maxInlineLength = encoding_ == CharEncoding::Latin1
+                                ? JSFatInlineString::MAX_LENGTH_LATIN1
+                                : JSFatInlineString::MAX_LENGTH_TWO_BYTE;
+  masm.branch32(Assembler::Above, temp1_, Imm32(maxInlineLength), &notInline);
+  {
+    // Make a thin or fat inline string.
+    Label stringAllocated, fatInline;
+
+    int32_t maxThinInlineLength = encoding_ == CharEncoding::Latin1
+                                      ? JSThinInlineString::MAX_LENGTH_LATIN1
+                                      : JSThinInlineString::MAX_LENGTH_TWO_BYTE;
+    masm.branch32(Assembler::Above, temp1_, Imm32(maxThinInlineLength),
+                  &fatInline);
+    if (encoding_ == CharEncoding::Latin1) {
+      // One character Latin-1 strings can be loaded directly from the
+      // static strings table.
+      Label thinInline;
+      masm.branch32(Assembler::Above, temp1_, Imm32(1), &thinInline);
+      {
+        static_assert(
+            StaticStrings::UNIT_STATIC_LIMIT - 1 == JSString::MAX_LATIN1_CHAR,
+            "Latin-1 strings can be loaded from static strings");
+
+        masm.loadStringChars(base, temp1_, encoding_);
+        masm.loadChar(temp1_, temp2_, temp1_, encoding_);
+
+        masm.movePtr(ImmPtr(&runtime->staticStrings().unitStaticTable),
+                     string_);
+        masm.loadPtr(BaseIndex(string_, temp1_, ScalePointer), string_);
+
+        masm.jump(&done);
+      }
+      masm.bind(&thinInline);
+    }
+    {
+      newGCString(FallbackKind::InlineString);
+      masm.jump(&stringAllocated);
+    }
+    masm.bind(&fatInline);
+    { newGCString(FallbackKind::FatInlineString); }
+    masm.bind(&stringAllocated);
+
+    masm.store32(temp1_, Address(string_, JSString::offsetOfLength()));
+
+    masm.push(string_);
+    masm.push(base);
+
+    // Adjust the start index address for the above pushes.
+    MOZ_ASSERT(startIndexAddress.base == masm.getStackPointer());
+    BaseIndex newStartIndexAddress = startIndexAddress;
+    newStartIndexAddress.offset += 2 * sizeof(void*);
+
+    // Load chars pointer for the new string.
+    masm.loadInlineStringCharsForStore(string_, string_);
+
+    // Load the source characters pointer.
+    masm.loadStringChars(base, temp2_, encoding_);
+    masm.load32(newStartIndexAddress, base);
+    masm.addToCharPtr(temp2_, base, encoding_);
+
+    CopyStringChars(masm, string_, temp2_, temp1_, base, encoding_);
+
+    masm.pop(base);
+    masm.pop(string_);
+
+    masm.jump(&done);
+  }
+
+  masm.bind(&notInline);
+
+  {
+    // Make a dependent string.
+    // Warning: string may be tenured (if the fallback case is hit), so
+    // stores into it must be post barriered.
+    newGCString(FallbackKind::NotInlineString);
+
+    masm.store32(temp1_, Address(string_, JSString::offsetOfLength()));
+
+    masm.loadNonInlineStringChars(base, temp1_, encoding_);
+    masm.load32(startIndexAddress, temp2_);
+    masm.addToCharPtr(temp1_, temp2_, encoding_);
+    masm.storeNonInlineStringChars(temp1_, string_);
+    masm.storeDependentStringBase(base, string_);
+    masm.movePtr(base, temp1_);
+
+    // Follow any base pointer if the input is itself a dependent string.
+    // Watch for undepended strings, which have a base pointer but don't
+    // actually share their characters with it.
+    Label noBase;
+    masm.load32(Address(base, JSString::offsetOfFlags()), temp2_);
+    masm.and32(Imm32(JSString::TYPE_FLAGS_MASK), temp2_);
+    masm.branchTest32(Assembler::Zero, temp2_, Imm32(JSString::DEPENDENT_BIT),
+                      &noBase);
+    masm.loadDependentStringBase(base, temp1_);
+    masm.storeDependentStringBase(temp1_, string_);
+    masm.bind(&noBase);
+
+    // Post-barrier the base store, whether it was the direct or indirect
+    // base (both will end up in temp1 here).
+    masm.branchPtrInNurseryChunk(Assembler::Equal, string_, temp2_, &done);
+    masm.branchPtrInNurseryChunk(Assembler::NotEqual, temp1_, temp2_, &done);
+
+    LiveRegisterSet regsToSave(RegisterSet::Volatile());
+    regsToSave.takeUnchecked(temp1_);
+    regsToSave.takeUnchecked(temp2_);
+
+    masm.PushRegsInMask(regsToSave);
+
+    masm.mov(ImmPtr(runtime), temp1_);
+
+    using Fn = void (*)(JSRuntime * rt, js::gc::Cell * cell);
+    masm.setupUnalignedABICall(temp2_);
+    masm.passABIArg(temp1_);
+    masm.passABIArg(string_);
+    masm.callWithABI<Fn, PostWriteBarrier>();
+
+    masm.PopRegsInMask(regsToSave);
+  }
+
+  masm.bind(&done);
+}
+
+void CreateDependentString::generateFallback(MacroAssembler& masm) {
+  JitSpew(JitSpew_Codegen,
+          "# Emitting CreateDependentString fallback (encoding=%s)",
+          (encoding_ == CharEncoding::Latin1 ? "Latin-1" : "Two-Byte"));
+
+  LiveRegisterSet regsToSave(RegisterSet::Volatile());
+  regsToSave.takeUnchecked(string_);
+  regsToSave.takeUnchecked(temp2_);
+
+  for (FallbackKind kind : mozilla::MakeEnumeratedRange(FallbackKind::Count)) {
+    masm.bind(&fallbacks_[kind]);
+
+    masm.PushRegsInMask(regsToSave);
+
+    using Fn = void* (*)(JSContext * cx);
+    masm.setupUnalignedABICall(string_);
+    masm.loadJSContext(string_);
+    masm.passABIArg(string_);
+    if (kind == FallbackKind::FatInlineString) {
+      masm.callWithABI<Fn, AllocateFatInlineString>();
+    } else {
+      masm.callWithABI<Fn, AllocateString>();
+    }
+    masm.storeCallPointerResult(string_);
+
+    masm.PopRegsInMask(regsToSave);
+
+    masm.branchPtr(Assembler::Equal, string_, ImmWord(0), failure_);
+
+    masm.jump(&joins_[kind]);
+  }
+}
+
+static void CreateMatchResultFallback(MacroAssembler& masm, Register object,
+                                      Register temp1, Register temp2,
+                                      const TemplateObject& templateObject,
+                                      Label* fail) {
+  JitSpew(JitSpew_Codegen, "# Emitting CreateMatchResult fallback");
+
+  MOZ_ASSERT(templateObject.isArrayObject());
+
+  LiveRegisterSet regsToSave(RegisterSet::Volatile());
+  regsToSave.takeUnchecked(object);
+  regsToSave.takeUnchecked(temp1);
+  regsToSave.takeUnchecked(temp2);
+
+  masm.PushRegsInMask(regsToSave);
+
+  using Fn =
+      void* (*)(JSContext * cx, gc::AllocKind kind, size_t nDynamicSlots);
+  masm.setupUnalignedABICall(object);
+
+  masm.loadJSContext(object);
+  masm.passABIArg(object);
+  masm.move32(Imm32(int32_t(templateObject.getAllocKind())), temp1);
+  masm.passABIArg(temp1);
+  masm.move32(
+      Imm32(int32_t(templateObject.asNativeTemplateObject().numDynamicSlots())),
+      temp2);
+  masm.passABIArg(temp2);
+  masm.callWithABI<Fn, CreateMatchResultFallbackFunc>();
+  masm.storeCallPointerResult(object);
+
+  masm.PopRegsInMask(regsToSave);
+
+  masm.branchPtr(Assembler::Equal, object, ImmWord(0), fail);
+
+  masm.initGCThing(object, temp1, templateObject, true);
+}
+
+JitCode* JitRealm::generateRegExpMatcherStub(JSContext* cx) {
+  JitSpew(JitSpew_Codegen, "# Emitting RegExpMatcher stub");
+
+  Register regexp = RegExpMatcherRegExpReg;
+  Register input = RegExpMatcherStringReg;
+  Register lastIndex = RegExpMatcherLastIndexReg;
+  ValueOperand result = JSReturnOperand;
+
+  // We are free to clobber all registers, as LRegExpMatcher is a call
+  // instruction.
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(input);
+  regs.take(regexp);
+  regs.take(lastIndex);
+
+  Register temp1 = regs.takeAny();
+  Register temp2 = regs.takeAny();
+  Register temp3 = regs.takeAny();
+  Register temp4 = regs.takeAny();
+  Register maybeTemp5 = InvalidReg;
+  if (!regs.empty()) {
+    // There are not enough registers on x86.
+    maybeTemp5 = regs.takeAny();
+  }
+
+  ArrayObject* templateObject =
+      cx->realm()->regExps.getOrCreateMatchResultTemplateObject(cx);
+  if (!templateObject) {
+    return nullptr;
+  }
+  TemplateObject templateObj(templateObject);
+  const NativeTemplateObject& nativeTemplateObj =
+      templateObj.asNativeTemplateObject();
+
+  // The template object should have enough space for the maximum number of
+  // pairs this stub can handle.
+  MOZ_ASSERT(ObjectElements::VALUES_PER_HEADER + RegExpObject::MaxPairCount ==
+             gc::GetGCKindSlots(templateObj.getAllocKind()));
+
+  StackMacroAssembler masm(cx);
+
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+
+  // The InputOutputData is placed above the return address on the stack.
+  size_t inputOutputDataStartOffset = sizeof(void*);
+
+  Label notFound, oolEntry;
+  if (!PrepareAndExecuteRegExp(cx, masm, regexp, input, lastIndex, temp1, temp2,
+                               temp3, inputOutputDataStartOffset,
+                               stringsCanBeInNursery, &notFound, &oolEntry)) {
+    return nullptr;
+  }
+
+  // If a regexp has named captures, fall back to the OOL stub, which
+  // will end up calling CreateRegExpMatchResults.
+  Register shared = temp2;
+  masm.unboxNonDouble(Address(regexp, NativeObject::getFixedSlotOffset(
+                                          RegExpObject::SHARED_SLOT)),
+                      shared, JSVAL_TYPE_PRIVATE_GCTHING);
+  masm.branchPtr(Assembler::NotEqual,
+                 Address(shared, RegExpShared::offsetOfGroupsTemplate()),
+                 ImmWord(0), &oolEntry);
+
+  // Construct the result.
+  Register object = temp1;
+  Label matchResultFallback, matchResultJoin;
+  masm.createGCObject(object, temp2, templateObj, gc::DefaultHeap,
+                      &matchResultFallback);
+  masm.bind(&matchResultJoin);
+
+  MOZ_ASSERT(nativeTemplateObj.numFixedSlots() == 0);
+  // Dynamic slot count is always one less than a power of 2.
+  MOZ_ASSERT(nativeTemplateObj.numDynamicSlots() == 3);
+  static_assert(RegExpRealm::MatchResultObjectIndexSlot == 0,
+                "First slot holds the 'index' property");
+  static_assert(RegExpRealm::MatchResultObjectInputSlot == 1,
+                "Second slot holds the 'input' property");
+  static_assert(RegExpRealm::MatchResultObjectGroupsSlot == 2,
+                "Third slot holds the 'groups' property");
+
+  // Initialize the slots of the result object with the dummy values
+  // defined in createMatchResultTemplateObject.
+  masm.loadPtr(Address(object, NativeObject::offsetOfSlots()), temp2);
+  masm.storeValue(
+      nativeTemplateObj.getSlot(RegExpRealm::MatchResultObjectIndexSlot),
+      Address(temp2, RegExpRealm::offsetOfMatchResultObjectIndexSlot()));
+  masm.storeValue(
+      nativeTemplateObj.getSlot(RegExpRealm::MatchResultObjectInputSlot),
+      Address(temp2, RegExpRealm::offsetOfMatchResultObjectInputSlot()));
+  masm.storeValue(
+      nativeTemplateObj.getSlot(RegExpRealm::MatchResultObjectGroupsSlot),
+      Address(temp2, RegExpRealm::offsetOfMatchResultObjectGroupsSlot()));
+
+  // clang-format off
+   /*
+    * [SMDOC] Stack layout for the RegExpMatcher stub
+    *
+    *                                    +---------------+
+    *                                    |Return-Address |
+    *                                    +---------------+
+    * inputOutputDataStartOffset +-----> +---------------+
+    *                                    |InputOutputData|
+    *                                    +---------------+
+    *                                    +---------------+
+    *                                    |  MatchPairs   |
+    *           pairsCountAddress +----------->  count   |
+    *                                    |       pairs   |
+    *                                    |               |
+    *                                    +---------------+
+    *     pairsVectorStartOffset +-----> +---------------+
+    *                                    |   MatchPair   |
+    *             matchPairStart +------------>  start   |  <-------+
+    *             matchPairLimit +------------>  limit   |          | Reserved space for
+    *                                    +---------------+          | `RegExpObject::MaxPairCount`
+    *                                           .                   | MatchPair objects.
+    *                                           .                   |
+    *                                           .                   | `count` objects will be
+    *                                    +---------------+          | initialized and can be
+    *                                    |   MatchPair   |          | accessed below.
+    *                                    |       start   |  <-------+
+    *                                    |       limit   |
+    *                                    +---------------+
+    */
+  // clang-format on
+
+  static_assert(sizeof(MatchPair) == 2 * sizeof(int32_t),
+                "MatchPair consists of two int32 values representing the start"
+                "and the end offset of the match");
+
+  Address pairCountAddress =
+      RegExpPairCountAddress(masm, inputOutputDataStartOffset);
+
+  size_t pairsVectorStartOffset =
+      RegExpPairsVectorStartOffset(inputOutputDataStartOffset);
+  Address firstMatchPairStartAddress(
+      masm.getStackPointer(),
+      pairsVectorStartOffset + offsetof(MatchPair, start));
+
+  // Incremented by one below for each match pair.
+  Register matchIndex = temp2;
+  masm.move32(Imm32(0), matchIndex);
+
+  // The element in which to store the result of the current match.
+  size_t elementsOffset = NativeObject::offsetOfFixedElements();
+  BaseObjectElementIndex objectMatchElement(object, matchIndex, elementsOffset);
+
+  // The current match pair's "start" and "limit" member.
+  BaseIndex matchPairStart(masm.getStackPointer(), matchIndex, TimesEight,
+                           pairsVectorStartOffset + offsetof(MatchPair, start));
+  BaseIndex matchPairLimit(masm.getStackPointer(), matchIndex, TimesEight,
+                           pairsVectorStartOffset + offsetof(MatchPair, limit));
+
+  Register temp5;
+  if (maybeTemp5 == InvalidReg) {
+    // We don't have enough registers for a fifth temporary. Reuse
+    // |lastIndex| as a temporary. We don't need to restore its value,
+    // because |lastIndex| is no longer used after a successful match.
+    // (Neither here nor in the OOL path, cf. js::RegExpMatcherRaw.)
+    temp5 = lastIndex;
+  } else {
+    temp5 = maybeTemp5;
+  }
+
+  // Loop to construct the match strings. There are two different loops,
+  // depending on whether the input is a Two-Byte or a Latin-1 string.
+  CreateDependentString depStrs[]{
+      {CharEncoding::TwoByte, temp3, temp4, temp5, &oolEntry},
+      {CharEncoding::Latin1, temp3, temp4, temp5, &oolEntry},
+  };
+
+  {
+    Label isLatin1, done;
+    masm.branchLatin1String(input, &isLatin1);
+
+    for (auto& depStr : depStrs) {
+      if (depStr.encoding() == CharEncoding::Latin1) {
+        masm.bind(&isLatin1);
+      }
+
+      Label matchLoop;
+      masm.bind(&matchLoop);
+
+      static_assert(MatchPair::NoMatch == -1,
+                    "MatchPair::start is negative if no match was found");
+
+      Label isUndefined, storeDone;
+      masm.branch32(Assembler::LessThan, matchPairStart, Imm32(0),
+                    &isUndefined);
+      {
+        depStr.generate(masm, cx->names(), CompileRuntime::get(cx->runtime()),
+                        input, matchPairStart, matchPairLimit,
+                        stringsCanBeInNursery);
+
+        // Storing into nursery-allocated results object's elements; no post
+        // barrier.
+        masm.storeValue(JSVAL_TYPE_STRING, depStr.string(), objectMatchElement);
+        masm.jump(&storeDone);
+      }
+      masm.bind(&isUndefined);
+      { masm.storeValue(UndefinedValue(), objectMatchElement); }
+      masm.bind(&storeDone);
+
+      masm.add32(Imm32(1), matchIndex);
+      masm.branch32(Assembler::LessThanOrEqual, pairCountAddress, matchIndex,
+                    &done);
+      masm.jump(&matchLoop);
+    }
+
+#ifdef DEBUG
+    masm.assumeUnreachable("The match string loop doesn't fall through.");
+#endif
+
+    masm.bind(&done);
+  }
+
+  // Fill in the rest of the output object.
+  masm.store32(
+      matchIndex,
+      Address(object,
+              elementsOffset + ObjectElements::offsetOfInitializedLength()));
+  masm.store32(
+      matchIndex,
+      Address(object, elementsOffset + ObjectElements::offsetOfLength()));
+
+  masm.loadPtr(Address(object, NativeObject::offsetOfSlots()), temp2);
+
+  masm.load32(firstMatchPairStartAddress, temp3);
+  masm.storeValue(JSVAL_TYPE_INT32, temp3, Address(temp2, 0));
+
+  // No post barrier needed (address is within nursery object.)
+  masm.storeValue(JSVAL_TYPE_STRING, input, Address(temp2, sizeof(Value)));
+
+  // All done!
+  masm.tagValue(JSVAL_TYPE_OBJECT, object, result);
+  masm.ret();
+
+  masm.bind(&notFound);
+  masm.moveValue(NullValue(), result);
+  masm.ret();
+
+  // Fallback paths for CreateDependentString.
+  for (auto& depStr : depStrs) {
+    depStr.generateFallback(masm);
+  }
+
+  // Fallback path for createGCObject.
+  masm.bind(&matchResultFallback);
+  CreateMatchResultFallback(masm, object, temp2, temp3, templateObj, &oolEntry);
+  masm.jump(&matchResultJoin);
+
+  // Use an undefined value to signal to the caller that the OOL stub needs to
+  // be called.
+  masm.bind(&oolEntry);
+  masm.moveValue(UndefinedValue(), result);
+  masm.ret();
+
+  Linker linker(masm);
+  JitCode* code = linker.newCode(cx, CodeKind::Other);
+  if (!code) {
+    return nullptr;
+  }
+
+#ifdef JS_ION_PERF
+  writePerfSpewerJitCodeProfile(code, "RegExpMatcherStub");
+#endif
+#ifdef MOZ_VTUNE
+  vtune::MarkStub(code, "RegExpMatcherStub");
+#endif
+
+  return code;
+}
+
+class OutOfLineRegExpMatcher : public OutOfLineCodeBase<CodeGenerator> {
+  LRegExpMatcher* lir_;
+
+ public:
+  explicit OutOfLineRegExpMatcher(LRegExpMatcher* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineRegExpMatcher(this);
+  }
+
+  LRegExpMatcher* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitOutOfLineRegExpMatcher(OutOfLineRegExpMatcher* ool) {
+  LRegExpMatcher* lir = ool->lir();
+  Register lastIndex = ToRegister(lir->lastIndex());
+  Register input = ToRegister(lir->string());
+  Register regexp = ToRegister(lir->regexp());
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(lastIndex);
+  regs.take(input);
+  regs.take(regexp);
+  Register temp = regs.takeAny();
+
+  masm.computeEffectiveAddress(
+      Address(masm.getStackPointer(), InputOutputDataSize), temp);
+
+  pushArg(temp);
+  pushArg(lastIndex);
+  pushArg(input);
+  pushArg(regexp);
+
+  // We are not using oolCallVM because we are in a Call, and that live
+  // registers are already saved by the the register allocator.
+  using Fn = bool (*)(JSContext*, HandleObject regexp, HandleString input,
+                      int32_t lastIndex, MatchPairs * pairs,
+                      MutableHandleValue output);
+  callVM<Fn, RegExpMatcherRaw>(lir);
+
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitRegExpMatcher(LRegExpMatcher* lir) {
+  MOZ_ASSERT(ToRegister(lir->regexp()) == RegExpMatcherRegExpReg);
+  MOZ_ASSERT(ToRegister(lir->string()) == RegExpMatcherStringReg);
+  MOZ_ASSERT(ToRegister(lir->lastIndex()) == RegExpMatcherLastIndexReg);
+  MOZ_ASSERT(ToOutValue(lir) == JSReturnOperand);
+
+#if defined(JS_NUNBOX32)
+  static_assert(RegExpMatcherRegExpReg != JSReturnReg_Type);
+  static_assert(RegExpMatcherRegExpReg != JSReturnReg_Data);
+  static_assert(RegExpMatcherStringReg != JSReturnReg_Type);
+  static_assert(RegExpMatcherStringReg != JSReturnReg_Data);
+  static_assert(RegExpMatcherLastIndexReg != JSReturnReg_Type);
+  static_assert(RegExpMatcherLastIndexReg != JSReturnReg_Data);
+#elif defined(JS_PUNBOX64)
+  static_assert(RegExpMatcherRegExpReg != JSReturnReg);
+  static_assert(RegExpMatcherStringReg != JSReturnReg);
+  static_assert(RegExpMatcherLastIndexReg != JSReturnReg);
+#endif
+
+  masm.reserveStack(RegExpReservedStack);
+
+  OutOfLineRegExpMatcher* ool = new (alloc()) OutOfLineRegExpMatcher(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  const JitRealm* jitRealm = gen->realm->jitRealm();
+  JitCode* regExpMatcherStub =
+      jitRealm->regExpMatcherStubNoBarrier(&realmStubsToReadBarrier_);
+  masm.call(regExpMatcherStub);
+  masm.branchTestUndefined(Assembler::Equal, JSReturnOperand, ool->entry());
+  masm.bind(ool->rejoin());
+
+  masm.freeStack(RegExpReservedStack);
+}
+
+static const int32_t RegExpSearcherResultNotFound = -1;
+static const int32_t RegExpSearcherResultFailed = -2;
+
+JitCode* JitRealm::generateRegExpSearcherStub(JSContext* cx) {
+  JitSpew(JitSpew_Codegen, "# Emitting RegExpSearcher stub");
+
+  Register regexp = RegExpTesterRegExpReg;
+  Register input = RegExpTesterStringReg;
+  Register lastIndex = RegExpTesterLastIndexReg;
+  Register result = ReturnReg;
+
+  // We are free to clobber all registers, as LRegExpSearcher is a call
+  // instruction.
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(input);
+  regs.take(regexp);
+  regs.take(lastIndex);
+
+  Register temp1 = regs.takeAny();
+  Register temp2 = regs.takeAny();
+  Register temp3 = regs.takeAny();
+
+  StackMacroAssembler masm(cx);
+
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+
+  // The InputOutputData is placed above the return address on the stack.
+  size_t inputOutputDataStartOffset = sizeof(void*);
+
+  Label notFound, oolEntry;
+  if (!PrepareAndExecuteRegExp(cx, masm, regexp, input, lastIndex, temp1, temp2,
+                               temp3, inputOutputDataStartOffset,
+                               stringsCanBeInNursery, &notFound, &oolEntry)) {
+    return nullptr;
+  }
+
+  // clang-format off
+    /*
+     * [SMDOC] Stack layout for the RegExpSearcher stub
+     *
+     *                                    +---------------+
+     *                                    |Return-Address |
+     *                                    +---------------+
+     * inputOutputDataStartOffset +-----> +---------------+
+     *                                    |InputOutputData|
+     *                                    +---------------+
+     *                                    +---------------+
+     *                                    |  MatchPairs   |
+     *                                    |       count   |
+     *                                    |       pairs   |
+     *                                    |               |
+     *                                    +---------------+
+     *     pairsVectorStartOffset +-----> +---------------+
+     *                                    |   MatchPair   |
+     *             matchPairStart +------------>  start   |  <-------+
+     *             matchPairLimit +------------>  limit   |          | Reserved space for
+     *                                    +---------------+          | `RegExpObject::MaxPairCount`
+     *                                           .                   | MatchPair objects.
+     *                                           .                   |
+     *                                           .                   | Only a single object will
+     *                                    +---------------+          | be initialized and can be
+     *                                    |   MatchPair   |          | accessed below.
+     *                                    |       start   |  <-------+
+     *                                    |       limit   |
+     *                                    +---------------+
+     */
+  // clang-format on
+
+  size_t pairsVectorStartOffset =
+      RegExpPairsVectorStartOffset(inputOutputDataStartOffset);
+  Address matchPairStart(masm.getStackPointer(),
+                         pairsVectorStartOffset + offsetof(MatchPair, start));
+  Address matchPairLimit(masm.getStackPointer(),
+                         pairsVectorStartOffset + offsetof(MatchPair, limit));
+
+  masm.load32(matchPairStart, result);
+  masm.load32(matchPairLimit, input);
+  masm.lshiftPtr(Imm32(15), input);
+  masm.or32(input, result);
+  masm.ret();
+
+  masm.bind(&notFound);
+  masm.move32(Imm32(RegExpSearcherResultNotFound), result);
+  masm.ret();
+
+  masm.bind(&oolEntry);
+  masm.move32(Imm32(RegExpSearcherResultFailed), result);
+  masm.ret();
+
+  Linker linker(masm);
+  JitCode* code = linker.newCode(cx, CodeKind::Other);
+  if (!code) {
+    return nullptr;
+  }
+
+#ifdef JS_ION_PERF
+  writePerfSpewerJitCodeProfile(code, "RegExpSearcherStub");
+#endif
+#ifdef MOZ_VTUNE
+  vtune::MarkStub(code, "RegExpSearcherStub");
+#endif
+
+  return code;
+}
+
+class OutOfLineRegExpSearcher : public OutOfLineCodeBase<CodeGenerator> {
+  LRegExpSearcher* lir_;
+
+ public:
+  explicit OutOfLineRegExpSearcher(LRegExpSearcher* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineRegExpSearcher(this);
+  }
+
+  LRegExpSearcher* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitOutOfLineRegExpSearcher(OutOfLineRegExpSearcher* ool) {
+  LRegExpSearcher* lir = ool->lir();
+  Register lastIndex = ToRegister(lir->lastIndex());
+  Register input = ToRegister(lir->string());
+  Register regexp = ToRegister(lir->regexp());
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(lastIndex);
+  regs.take(input);
+  regs.take(regexp);
+  Register temp = regs.takeAny();
+
+  masm.computeEffectiveAddress(
+      Address(masm.getStackPointer(), InputOutputDataSize), temp);
+
+  pushArg(temp);
+  pushArg(lastIndex);
+  pushArg(input);
+  pushArg(regexp);
+
+  // We are not using oolCallVM because we are in a Call, and that live
+  // registers are already saved by the the register allocator.
+  using Fn = bool (*)(JSContext * cx, HandleObject regexp, HandleString input,
+                      int32_t lastIndex, MatchPairs * pairs, int32_t * result);
+  callVM<Fn, RegExpSearcherRaw>(lir);
+
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitRegExpSearcher(LRegExpSearcher* lir) {
+  MOZ_ASSERT(ToRegister(lir->regexp()) == RegExpTesterRegExpReg);
+  MOZ_ASSERT(ToRegister(lir->string()) == RegExpTesterStringReg);
+  MOZ_ASSERT(ToRegister(lir->lastIndex()) == RegExpTesterLastIndexReg);
+  MOZ_ASSERT(ToRegister(lir->output()) == ReturnReg);
+
+  static_assert(RegExpTesterRegExpReg != ReturnReg);
+  static_assert(RegExpTesterStringReg != ReturnReg);
+  static_assert(RegExpTesterLastIndexReg != ReturnReg);
+
+  masm.reserveStack(RegExpReservedStack);
+
+  OutOfLineRegExpSearcher* ool = new (alloc()) OutOfLineRegExpSearcher(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  const JitRealm* jitRealm = gen->realm->jitRealm();
+  JitCode* regExpSearcherStub =
+      jitRealm->regExpSearcherStubNoBarrier(&realmStubsToReadBarrier_);
+  masm.call(regExpSearcherStub);
+  masm.branch32(Assembler::Equal, ReturnReg, Imm32(RegExpSearcherResultFailed),
+                ool->entry());
+  masm.bind(ool->rejoin());
+
+  masm.freeStack(RegExpReservedStack);
+}
+
+static const int32_t RegExpTesterResultNotFound = -1;
+static const int32_t RegExpTesterResultFailed = -2;
+
+JitCode* JitRealm::generateRegExpTesterStub(JSContext* cx) {
+  JitSpew(JitSpew_Codegen, "# Emitting RegExpTester stub");
+
+  Register regexp = RegExpTesterRegExpReg;
+  Register input = RegExpTesterStringReg;
+  Register lastIndex = RegExpTesterLastIndexReg;
+  Register result = ReturnReg;
+
+  StackMacroAssembler masm(cx);
+
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+
+  // We are free to clobber all registers, as LRegExpTester is a call
+  // instruction.
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(input);
+  regs.take(regexp);
+  regs.take(lastIndex);
+
+  Register temp1 = regs.takeAny();
+  Register temp2 = regs.takeAny();
+  Register temp3 = regs.takeAny();
+
+  masm.reserveStack(RegExpReservedStack);
+
+  Label notFound, oolEntry;
+  if (!PrepareAndExecuteRegExp(cx, masm, regexp, input, lastIndex, temp1, temp2,
+                               temp3, 0, stringsCanBeInNursery, &notFound,
+                               &oolEntry)) {
+    return nullptr;
+  }
+
+  Label done;
+
+  // In visitRegExpMatcher and visitRegExpSearcher, we reserve stack space
+  // before calling the stub. For RegExpTester we call the stub before reserving
+  // stack space, so the offset of the InputOutputData is 0.
+  size_t inputOutputDataStartOffset = 0;
+
+  size_t pairsVectorStartOffset =
+      RegExpPairsVectorStartOffset(inputOutputDataStartOffset);
+  Address matchPairLimit(masm.getStackPointer(),
+                         pairsVectorStartOffset + offsetof(MatchPair, limit));
+
+  // RegExpTester returns the end index of the match to update lastIndex.
+  masm.load32(matchPairLimit, result);
+  masm.jump(&done);
+
+  masm.bind(&notFound);
+  masm.move32(Imm32(RegExpTesterResultNotFound), result);
+  masm.jump(&done);
+
+  masm.bind(&oolEntry);
+  masm.move32(Imm32(RegExpTesterResultFailed), result);
+
+  masm.bind(&done);
+  masm.freeStack(RegExpReservedStack);
+  masm.ret();
+
+  Linker linker(masm);
+  JitCode* code = linker.newCode(cx, CodeKind::Other);
+  if (!code) {
+    return nullptr;
+  }
+
+#ifdef JS_ION_PERF
+  writePerfSpewerJitCodeProfile(code, "RegExpTesterStub");
+#endif
+#ifdef MOZ_VTUNE
+  vtune::MarkStub(code, "RegExpTesterStub");
+#endif
+
+  return code;
+}
+
+class OutOfLineRegExpTester : public OutOfLineCodeBase<CodeGenerator> {
+  LRegExpTester* lir_;
+
+ public:
+  explicit OutOfLineRegExpTester(LRegExpTester* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineRegExpTester(this);
+  }
+
+  LRegExpTester* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitOutOfLineRegExpTester(OutOfLineRegExpTester* ool) {
+  LRegExpTester* lir = ool->lir();
+  Register lastIndex = ToRegister(lir->lastIndex());
+  Register input = ToRegister(lir->string());
+  Register regexp = ToRegister(lir->regexp());
+
+  pushArg(lastIndex);
+  pushArg(input);
+  pushArg(regexp);
+
+  // We are not using oolCallVM because we are in a Call, and that live
+  // registers are already saved by the the register allocator.
+  using Fn = bool (*)(JSContext * cx, HandleObject regexp, HandleString input,
+                      int32_t lastIndex, int32_t * result);
+  callVM<Fn, RegExpTesterRaw>(lir);
+
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitRegExpTester(LRegExpTester* lir) {
+  MOZ_ASSERT(ToRegister(lir->regexp()) == RegExpTesterRegExpReg);
+  MOZ_ASSERT(ToRegister(lir->string()) == RegExpTesterStringReg);
+  MOZ_ASSERT(ToRegister(lir->lastIndex()) == RegExpTesterLastIndexReg);
+  MOZ_ASSERT(ToRegister(lir->output()) == ReturnReg);
+
+  static_assert(RegExpTesterRegExpReg != ReturnReg);
+  static_assert(RegExpTesterStringReg != ReturnReg);
+  static_assert(RegExpTesterLastIndexReg != ReturnReg);
+
+  OutOfLineRegExpTester* ool = new (alloc()) OutOfLineRegExpTester(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  const JitRealm* jitRealm = gen->realm->jitRealm();
+  JitCode* regExpTesterStub =
+      jitRealm->regExpTesterStubNoBarrier(&realmStubsToReadBarrier_);
+  masm.call(regExpTesterStub);
+
+  masm.branch32(Assembler::Equal, ReturnReg, Imm32(RegExpTesterResultFailed),
+                ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+class OutOfLineRegExpPrototypeOptimizable
+    : public OutOfLineCodeBase<CodeGenerator> {
+  LRegExpPrototypeOptimizable* ins_;
+
+ public:
+  explicit OutOfLineRegExpPrototypeOptimizable(LRegExpPrototypeOptimizable* ins)
+      : ins_(ins) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineRegExpPrototypeOptimizable(this);
+  }
+  LRegExpPrototypeOptimizable* ins() const { return ins_; }
+};
+
+void CodeGenerator::visitRegExpPrototypeOptimizable(
+    LRegExpPrototypeOptimizable* ins) {
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+  Register temp = ToRegister(ins->temp());
+
+  OutOfLineRegExpPrototypeOptimizable* ool =
+      new (alloc()) OutOfLineRegExpPrototypeOptimizable(ins);
+  addOutOfLineCode(ool, ins->mir());
+
+  masm.branchIfNotRegExpPrototypeOptimizable(object, temp, ool->entry());
+  masm.move32(Imm32(0x1), output);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineRegExpPrototypeOptimizable(
+    OutOfLineRegExpPrototypeOptimizable* ool) {
+  LRegExpPrototypeOptimizable* ins = ool->ins();
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+
+  saveVolatile(output);
+
+  using Fn = bool (*)(JSContext * cx, JSObject * proto);
+  masm.setupUnalignedABICall(output);
+  masm.loadJSContext(output);
+  masm.passABIArg(output);
+  masm.passABIArg(object);
+  masm.callWithABI<Fn, RegExpPrototypeOptimizableRaw>();
+  masm.storeCallBoolResult(output);
+
+  restoreVolatile(output);
+
+  masm.jump(ool->rejoin());
+}
+
+class OutOfLineRegExpInstanceOptimizable
+    : public OutOfLineCodeBase<CodeGenerator> {
+  LRegExpInstanceOptimizable* ins_;
+
+ public:
+  explicit OutOfLineRegExpInstanceOptimizable(LRegExpInstanceOptimizable* ins)
+      : ins_(ins) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineRegExpInstanceOptimizable(this);
+  }
+  LRegExpInstanceOptimizable* ins() const { return ins_; }
+};
+
+void CodeGenerator::visitRegExpInstanceOptimizable(
+    LRegExpInstanceOptimizable* ins) {
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+  Register temp = ToRegister(ins->temp());
+
+  OutOfLineRegExpInstanceOptimizable* ool =
+      new (alloc()) OutOfLineRegExpInstanceOptimizable(ins);
+  addOutOfLineCode(ool, ins->mir());
+
+  masm.branchIfNotRegExpInstanceOptimizable(object, temp, ool->entry());
+  masm.move32(Imm32(0x1), output);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineRegExpInstanceOptimizable(
+    OutOfLineRegExpInstanceOptimizable* ool) {
+  LRegExpInstanceOptimizable* ins = ool->ins();
+  Register object = ToRegister(ins->object());
+  Register proto = ToRegister(ins->proto());
+  Register output = ToRegister(ins->output());
+
+  saveVolatile(output);
+
+  using Fn = bool (*)(JSContext * cx, JSObject * obj, JSObject * proto);
+  masm.setupUnalignedABICall(output);
+  masm.loadJSContext(output);
+  masm.passABIArg(output);
+  masm.passABIArg(object);
+  masm.passABIArg(proto);
+  masm.callWithABI<Fn, RegExpInstanceOptimizableRaw>();
+  masm.storeCallBoolResult(output);
+
+  restoreVolatile(output);
+
+  masm.jump(ool->rejoin());
+}
+
+static void FindFirstDollarIndex(MacroAssembler& masm, Register str,
+                                 Register len, Register temp0, Register temp1,
+                                 Register output, CharEncoding encoding) {
+#ifdef DEBUG
+  Label ok;
+  masm.branch32(Assembler::GreaterThan, len, Imm32(0), &ok);
+  masm.assumeUnreachable("Length should be greater than 0.");
+  masm.bind(&ok);
+#endif
+
+  Register chars = temp0;
+  masm.loadStringChars(str, chars, encoding);
+
+  masm.move32(Imm32(0), output);
+
+  Label start, done;
+  masm.bind(&start);
+
+  Register currentChar = temp1;
+  masm.loadChar(chars, output, currentChar, encoding);
+  masm.branch32(Assembler::Equal, currentChar, Imm32('$'), &done);
+
+  masm.add32(Imm32(1), output);
+  masm.branch32(Assembler::NotEqual, output, len, &start);
+
+  masm.move32(Imm32(-1), output);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitGetFirstDollarIndex(LGetFirstDollarIndex* ins) {
+  Register str = ToRegister(ins->str());
+  Register output = ToRegister(ins->output());
+  Register temp0 = ToRegister(ins->temp0());
+  Register temp1 = ToRegister(ins->temp1());
+  Register len = ToRegister(ins->temp2());
+
+  using Fn = bool (*)(JSContext*, JSString*, int32_t*);
+  OutOfLineCode* ool = oolCallVM<Fn, GetFirstDollarIndexRaw>(
+      ins, ArgList(str), StoreRegisterTo(output));
+
+  masm.branchIfRope(str, ool->entry());
+  masm.loadStringLength(str, len);
+
+  Label isLatin1, done;
+  masm.branchLatin1String(str, &isLatin1);
+  {
+    FindFirstDollarIndex(masm, str, len, temp0, temp1, output,
+                         CharEncoding::TwoByte);
+    masm.jump(&done);
+  }
+  masm.bind(&isLatin1);
+  {
+    FindFirstDollarIndex(masm, str, len, temp0, temp1, output,
+                         CharEncoding::Latin1);
+  }
+  masm.bind(&done);
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitStringReplace(LStringReplace* lir) {
+  if (lir->replacement()->isConstant()) {
+    pushArg(ImmGCPtr(lir->replacement()->toConstant()->toString()));
+  } else {
+    pushArg(ToRegister(lir->replacement()));
+  }
+
+  if (lir->pattern()->isConstant()) {
+    pushArg(ImmGCPtr(lir->pattern()->toConstant()->toString()));
+  } else {
+    pushArg(ToRegister(lir->pattern()));
+  }
+
+  if (lir->string()->isConstant()) {
+    pushArg(ImmGCPtr(lir->string()->toConstant()->toString()));
+  } else {
+    pushArg(ToRegister(lir->string()));
+  }
+
+  using Fn =
+      JSString* (*)(JSContext*, HandleString, HandleString, HandleString);
+  if (lir->mir()->isFlatReplacement()) {
+    callVM<Fn, StringFlatReplaceString>(lir);
+  } else {
+    callVM<Fn, StringReplace>(lir);
+  }
+}
+
+void CodeGenerator::visitBinaryValueCache(LBinaryValueCache* lir) {
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+  TypedOrValueRegister lhs =
+      TypedOrValueRegister(ToValue(lir, LBinaryValueCache::LhsInput));
+  TypedOrValueRegister rhs =
+      TypedOrValueRegister(ToValue(lir, LBinaryValueCache::RhsInput));
+  ValueOperand output = ToOutValue(lir);
+
+  JSOp jsop = JSOp(*lir->mirRaw()->toInstruction()->resumePoint()->pc());
+
+  switch (jsop) {
+    case JSOp::Add:
+    case JSOp::Sub:
+    case JSOp::Mul:
+    case JSOp::Div:
+    case JSOp::Mod:
+    case JSOp::Pow:
+    case JSOp::BitAnd:
+    case JSOp::BitOr:
+    case JSOp::BitXor:
+    case JSOp::Lsh:
+    case JSOp::Rsh:
+    case JSOp::Ursh: {
+      IonBinaryArithIC ic(liveRegs, lhs, rhs, output);
+      addIC(lir, allocateIC(ic));
+      return;
+    }
+    default:
+      MOZ_CRASH("Unsupported jsop in MBinaryValueCache");
+  }
+}
+
+void CodeGenerator::visitBinaryBoolCache(LBinaryBoolCache* lir) {
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+  TypedOrValueRegister lhs =
+      TypedOrValueRegister(ToValue(lir, LBinaryBoolCache::LhsInput));
+  TypedOrValueRegister rhs =
+      TypedOrValueRegister(ToValue(lir, LBinaryBoolCache::RhsInput));
+  Register output = ToRegister(lir->output());
+
+  JSOp jsop = JSOp(*lir->mirRaw()->toInstruction()->resumePoint()->pc());
+
+  switch (jsop) {
+    case JSOp::Lt:
+    case JSOp::Le:
+    case JSOp::Gt:
+    case JSOp::Ge:
+    case JSOp::Eq:
+    case JSOp::Ne:
+    case JSOp::StrictEq:
+    case JSOp::StrictNe: {
+      IonCompareIC ic(liveRegs, lhs, rhs, output);
+      addIC(lir, allocateIC(ic));
+      return;
+    }
+    default:
+      MOZ_CRASH("Unsupported jsop in MBinaryBoolCache");
+  }
+}
+
+void CodeGenerator::visitUnaryCache(LUnaryCache* lir) {
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+  TypedOrValueRegister input =
+      TypedOrValueRegister(ToValue(lir, LUnaryCache::Input));
+  ValueOperand output = ToOutValue(lir);
+
+  IonUnaryArithIC ic(liveRegs, input, output);
+  addIC(lir, allocateIC(ic));
+}
+
+void CodeGenerator::visitClassConstructor(LClassConstructor* lir) {
+  pushArg(ImmPtr(nullptr));
+  pushArg(ImmPtr(lir->mir()->pc()));
+  pushArg(ImmGCPtr(current->mir()->info().script()));
+
+  using Fn =
+      JSFunction* (*)(JSContext*, HandleScript, jsbytecode*, HandleObject);
+  callVM<Fn, js::MakeDefaultConstructor>(lir);
+}
+
+void CodeGenerator::visitDerivedClassConstructor(
+    LDerivedClassConstructor* lir) {
+  pushArg(ToRegister(lir->prototype()));
+  pushArg(ImmPtr(lir->mir()->pc()));
+  pushArg(ImmGCPtr(current->mir()->info().script()));
+
+  using Fn =
+      JSFunction* (*)(JSContext*, HandleScript, jsbytecode*, HandleObject);
+  callVM<Fn, js::MakeDefaultConstructor>(lir);
+}
+
+void CodeGenerator::visitModuleMetadata(LModuleMetadata* lir) {
+  pushArg(ImmPtr(lir->mir()->module()));
+
+  using Fn = JSObject* (*)(JSContext*, HandleObject);
+  callVM<Fn, js::GetOrCreateModuleMetaObject>(lir);
+}
+
+void CodeGenerator::visitDynamicImport(LDynamicImport* lir) {
+  pushArg(ToValue(lir, LDynamicImport::SpecifierIndex));
+  pushArg(ImmGCPtr(current->mir()->info().script()));
+
+  using Fn = JSObject* (*)(JSContext*, HandleScript, HandleValue);
+  callVM<Fn, js::StartDynamicModuleImport>(lir);
+}
+
+void CodeGenerator::visitLambda(LLambda* lir) {
+  Register envChain = ToRegister(lir->environmentChain());
+  Register output = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+  const LambdaFunctionInfo& info = lir->mir()->info();
+
+  using Fn = JSObject* (*)(JSContext*, HandleFunction, HandleObject);
+  OutOfLineCode* ool = oolCallVM<Fn, js::Lambda>(
+      lir, ArgList(ImmGCPtr(info.funUnsafe()), envChain),
+      StoreRegisterTo(output));
+
+  TemplateObject templateObject(info.funUnsafe());
+  masm.createGCObject(output, tempReg, templateObject, gc::DefaultHeap,
+                      ool->entry());
+
+  emitLambdaInit(output, envChain, info);
+
+  if (info.flags.isExtended()) {
+    MOZ_ASSERT(info.flags.allowSuperProperty() ||
+               info.flags.isSelfHostedBuiltin());
+    static_assert(FunctionExtended::NUM_EXTENDED_SLOTS == 2,
+                  "All slots must be initialized");
+    masm.storeValue(UndefinedValue(),
+                    Address(output, FunctionExtended::offsetOfExtendedSlot(0)));
+    masm.storeValue(UndefinedValue(),
+                    Address(output, FunctionExtended::offsetOfExtendedSlot(1)));
+  }
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitLambdaArrow(LLambdaArrow* lir) {
+  Register envChain = ToRegister(lir->environmentChain());
+  ValueOperand newTarget = ToValue(lir, LLambdaArrow::NewTargetValue);
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+  const LambdaFunctionInfo& info = lir->mir()->info();
+
+  using Fn =
+      JSObject* (*)(JSContext*, HandleFunction, HandleObject, HandleValue);
+  OutOfLineCode* ool = oolCallVM<Fn, LambdaArrow>(
+      lir, ArgList(ImmGCPtr(info.funUnsafe()), envChain, newTarget),
+      StoreRegisterTo(output));
+
+  TemplateObject templateObject(info.funUnsafe());
+  masm.createGCObject(output, temp, templateObject, gc::DefaultHeap,
+                      ool->entry());
+
+  emitLambdaInit(output, envChain, info);
+
+  // Initialize extended slots. Lexical |this| is stored in the first one.
+  MOZ_ASSERT(info.flags.isExtended());
+  static_assert(FunctionExtended::NUM_EXTENDED_SLOTS == 2,
+                "All slots must be initialized");
+  static_assert(FunctionExtended::ARROW_NEWTARGET_SLOT == 0,
+                "|new.target| must be stored in first slot");
+  masm.storeValue(newTarget,
+                  Address(output, FunctionExtended::offsetOfExtendedSlot(0)));
+  masm.storeValue(UndefinedValue(),
+                  Address(output, FunctionExtended::offsetOfExtendedSlot(1)));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::emitLambdaInit(Register output, Register envChain,
+                                   const LambdaFunctionInfo& info) {
+  // Initialize nargs and flags. We do this with a single uint32 to avoid
+  // 16-bit writes.
+  union {
+    struct S {
+      uint16_t nargs;
+      uint16_t flags;
+    } s;
+    uint32_t word;
+  } u;
+  u.s.nargs = info.nargs;
+  u.s.flags = info.flags.toRaw();
+
+  static_assert(JSFunction::offsetOfFlags() == JSFunction::offsetOfNargs() + 2,
+                "the code below needs to be adapted");
+  masm.store32(Imm32(u.word), Address(output, JSFunction::offsetOfNargs()));
+  masm.storePtr(ImmGCPtr(info.baseScript),
+                Address(output, JSFunction::offsetOfBaseScript()));
+  masm.storePtr(envChain, Address(output, JSFunction::offsetOfEnvironment()));
+  // No post barrier needed because output is guaranteed to be allocated in
+  // the nursery.
+  masm.storePtr(ImmGCPtr(info.funUnsafe()->displayAtom()),
+                Address(output, JSFunction::offsetOfAtom()));
+}
+
+void CodeGenerator::visitFunctionWithProto(LFunctionWithProto* lir) {
+  Register envChain = ToRegister(lir->environmentChain());
+  Register prototype = ToRegister(lir->prototype());
+
+  pushArg(prototype);
+  pushArg(envChain);
+  pushArg(ImmGCPtr(lir->mir()->function()));
+
+  using Fn =
+      JSObject* (*)(JSContext*, HandleFunction, HandleObject, HandleObject);
+  callVM<Fn, js::FunWithProtoOperation>(lir);
+}
+
+void CodeGenerator::visitSetFunName(LSetFunName* lir) {
+  pushArg(Imm32(lir->mir()->prefixKind()));
+  pushArg(ToValue(lir, LSetFunName::NameValue));
+  pushArg(ToRegister(lir->fun()));
+
+  using Fn =
+      bool (*)(JSContext*, HandleFunction, HandleValue, FunctionPrefixKind);
+  callVM<Fn, js::SetFunctionName>(lir);
+}
+
+void CodeGenerator::visitOsiPoint(LOsiPoint* lir) {
+  // Note: markOsiPoint ensures enough space exists between the last
+  // LOsiPoint and this one to patch adjacent call instructions.
+
+  MOZ_ASSERT(masm.framePushed() == frameSize());
+
+  uint32_t osiCallPointOffset = markOsiPoint(lir);
+
+  LSafepoint* safepoint = lir->associatedSafepoint();
+  MOZ_ASSERT(!safepoint->osiCallPointOffset());
+  safepoint->setOsiCallPointOffset(osiCallPointOffset);
+
+#ifdef DEBUG
+  // There should be no movegroups or other instructions between
+  // an instruction and its OsiPoint. This is necessary because
+  // we use the OsiPoint's snapshot from within VM calls.
+  for (LInstructionReverseIterator iter(current->rbegin(lir));
+       iter != current->rend(); iter++) {
+    if (*iter == lir) {
+      continue;
+    }
+    MOZ_ASSERT(!iter->isMoveGroup());
+    MOZ_ASSERT(iter->safepoint() == safepoint);
+    break;
+  }
+#endif
+
+#ifdef CHECK_OSIPOINT_REGISTERS
+  if (shouldVerifyOsiPointRegs(safepoint)) {
+    verifyOsiPointRegs(safepoint);
+  }
+#endif
+}
+
+void CodeGenerator::visitPhi(LPhi* lir) {
+  MOZ_CRASH("Unexpected LPhi in CodeGenerator");
+}
+
+void CodeGenerator::visitGoto(LGoto* lir) { jumpToBlock(lir->target()); }
+
+void CodeGenerator::visitTableSwitch(LTableSwitch* ins) {
+  MTableSwitch* mir = ins->mir();
+  Label* defaultcase = skipTrivialBlocks(mir->getDefault())->lir()->label();
+  const LAllocation* temp;
+
+  if (mir->getOperand(0)->type() != MIRType::Int32) {
+    temp = ins->tempInt()->output();
+
+    // The input is a double, so try and convert it to an integer.
+    // If it does not fit in an integer, take the default case.
+    masm.convertDoubleToInt32(ToFloatRegister(ins->index()), ToRegister(temp),
+                              defaultcase, false);
+  } else {
+    temp = ins->index();
+  }
+
+  emitTableSwitchDispatch(mir, ToRegister(temp),
+                          ToRegisterOrInvalid(ins->tempPointer()));
+}
+
+void CodeGenerator::visitTableSwitchV(LTableSwitchV* ins) {
+  MTableSwitch* mir = ins->mir();
+  Label* defaultcase = skipTrivialBlocks(mir->getDefault())->lir()->label();
+
+  Register index = ToRegister(ins->tempInt());
+  ValueOperand value = ToValue(ins, LTableSwitchV::InputValue);
+  Register tag = masm.extractTag(value, index);
+  masm.branchTestNumber(Assembler::NotEqual, tag, defaultcase);
+
+  Label unboxInt, isInt;
+  masm.branchTestInt32(Assembler::Equal, tag, &unboxInt);
+  {
+    FloatRegister floatIndex = ToFloatRegister(ins->tempFloat());
+    masm.unboxDouble(value, floatIndex);
+    masm.convertDoubleToInt32(floatIndex, index, defaultcase, false);
+    masm.jump(&isInt);
+  }
+
+  masm.bind(&unboxInt);
+  masm.unboxInt32(value, index);
+
+  masm.bind(&isInt);
+
+  emitTableSwitchDispatch(mir, index, ToRegisterOrInvalid(ins->tempPointer()));
+}
+
+void CodeGenerator::visitParameter(LParameter* lir) {}
+
+void CodeGenerator::visitCallee(LCallee* lir) {
+  Register callee = ToRegister(lir->output());
+  Address ptr(masm.getStackPointer(),
+              frameSize() + JitFrameLayout::offsetOfCalleeToken());
+
+  masm.loadFunctionFromCalleeToken(ptr, callee);
+}
+
+void CodeGenerator::visitIsConstructing(LIsConstructing* lir) {
+  Register output = ToRegister(lir->output());
+  Address calleeToken(masm.getStackPointer(),
+                      frameSize() + JitFrameLayout::offsetOfCalleeToken());
+  masm.loadPtr(calleeToken, output);
+
+  // We must be inside a function.
+  MOZ_ASSERT(current->mir()->info().script()->function());
+
+  // The low bit indicates whether this call is constructing, just clear the
+  // other bits.
+  static_assert(CalleeToken_Function == 0x0,
+                "CalleeTokenTag value should match");
+  static_assert(CalleeToken_FunctionConstructing == 0x1,
+                "CalleeTokenTag value should match");
+  masm.andPtr(Imm32(0x1), output);
+}
+
+void CodeGenerator::visitReturn(LReturn* lir) {
+#if defined(JS_NUNBOX32)
+  DebugOnly<LAllocation*> type = lir->getOperand(TYPE_INDEX);
+  DebugOnly<LAllocation*> payload = lir->getOperand(PAYLOAD_INDEX);
+  MOZ_ASSERT(ToRegister(type) == JSReturnReg_Type);
+  MOZ_ASSERT(ToRegister(payload) == JSReturnReg_Data);
+#elif defined(JS_PUNBOX64)
+  DebugOnly<LAllocation*> result = lir->getOperand(0);
+  MOZ_ASSERT(ToRegister(result) == JSReturnReg);
+#endif
+  // Don't emit a jump to the return label if this is the last block, as
+  // it'll fall through to the epilogue.
+  //
+  // This is -not- true however for a Generator-return, which may appear in the
+  // middle of the last block, so we should always emit the jump there.
+  if (current->mir() != *gen->graph().poBegin() || lir->isGenerator()) {
+    masm.jump(&returnLabel_);
+  }
+}
+
+void CodeGenerator::visitOsrEntry(LOsrEntry* lir) {
+  Register temp = ToRegister(lir->temp());
+
+  // Remember the OSR entry offset into the code buffer.
+  masm.flushBuffer();
+  setOsrEntryOffset(masm.size());
+
+#ifdef JS_TRACE_LOGGING
+  if (JS::TraceLoggerSupported()) {
+    emitTracelogStopEvent(TraceLogger_Baseline);
+    emitTracelogStartEvent(TraceLogger_IonMonkey);
+  }
+#endif
+
+  // If profiling, save the current frame pointer to a per-thread global field.
+  if (isProfilerInstrumentationEnabled()) {
+    masm.profilerEnterFrame(masm.getStackPointer(), temp);
+  }
+
+  // Allocate the full frame for this function
+  // Note we have a new entry here. So we reset MacroAssembler::framePushed()
+  // to 0, before reserving the stack.
+  MOZ_ASSERT(masm.framePushed() == frameSize());
+  masm.setFramePushed(0);
+
+  // Ensure that the Ion frames is properly aligned.
+  masm.assertStackAlignment(JitStackAlignment, 0);
+
+  masm.reserveStack(frameSize());
+}
+
+void CodeGenerator::visitOsrEnvironmentChain(LOsrEnvironmentChain* lir) {
+  const LAllocation* frame = lir->getOperand(0);
+  const LDefinition* object = lir->getDef(0);
+
+  const ptrdiff_t frameOffset =
+      BaselineFrame::reverseOffsetOfEnvironmentChain();
+
+  masm.loadPtr(Address(ToRegister(frame), frameOffset), ToRegister(object));
+}
+
+void CodeGenerator::visitOsrArgumentsObject(LOsrArgumentsObject* lir) {
+  const LAllocation* frame = lir->getOperand(0);
+  const LDefinition* object = lir->getDef(0);
+
+  const ptrdiff_t frameOffset = BaselineFrame::reverseOffsetOfArgsObj();
+
+  masm.loadPtr(Address(ToRegister(frame), frameOffset), ToRegister(object));
+}
+
+void CodeGenerator::visitOsrValue(LOsrValue* value) {
+  const LAllocation* frame = value->getOperand(0);
+  const ValueOperand out = ToOutValue(value);
+
+  const ptrdiff_t frameOffset = value->mir()->frameOffset();
+
+  masm.loadValue(Address(ToRegister(frame), frameOffset), out);
+}
+
+void CodeGenerator::visitOsrReturnValue(LOsrReturnValue* lir) {
+  const LAllocation* frame = lir->getOperand(0);
+  const ValueOperand out = ToOutValue(lir);
+
+  Address flags =
+      Address(ToRegister(frame), BaselineFrame::reverseOffsetOfFlags());
+  Address retval =
+      Address(ToRegister(frame), BaselineFrame::reverseOffsetOfReturnValue());
+
+  masm.moveValue(UndefinedValue(), out);
+
+  Label done;
+  masm.branchTest32(Assembler::Zero, flags, Imm32(BaselineFrame::HAS_RVAL),
+                    &done);
+  masm.loadValue(retval, out);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitStackArgT(LStackArgT* lir) {
+  const LAllocation* arg = lir->getArgument();
+  MIRType argType = lir->type();
+  uint32_t argslot = lir->argslot();
+  MOZ_ASSERT(argslot - 1u < graph.argumentSlotCount());
+
+  int32_t stack_offset = StackOffsetOfPassedArg(argslot);
+  Address dest(masm.getStackPointer(), stack_offset);
+
+  if (arg->isFloatReg()) {
+    masm.boxDouble(ToFloatRegister(arg), dest);
+  } else if (arg->isRegister()) {
+    masm.storeValue(ValueTypeFromMIRType(argType), ToRegister(arg), dest);
+  } else {
+    masm.storeValue(arg->toConstant()->toJSValue(), dest);
+  }
+}
+
+void CodeGenerator::visitStackArgV(LStackArgV* lir) {
+  ValueOperand val = ToValue(lir, 0);
+  uint32_t argslot = lir->argslot();
+  MOZ_ASSERT(argslot - 1u < graph.argumentSlotCount());
+
+  int32_t stack_offset = StackOffsetOfPassedArg(argslot);
+
+  masm.storeValue(val, Address(masm.getStackPointer(), stack_offset));
+}
+
+void CodeGenerator::visitMoveGroup(LMoveGroup* group) {
+  if (!group->numMoves()) {
+    return;
+  }
+
+  MoveResolver& resolver = masm.moveResolver();
+
+  for (size_t i = 0; i < group->numMoves(); i++) {
+    const LMove& move = group->getMove(i);
+
+    LAllocation from = move.from();
+    LAllocation to = move.to();
+    LDefinition::Type type = move.type();
+
+    // No bogus moves.
+    MOZ_ASSERT(from != to);
+    MOZ_ASSERT(!from.isConstant());
+    MoveOp::Type moveType;
+    switch (type) {
+      case LDefinition::OBJECT:
+      case LDefinition::SLOTS:
+#ifdef JS_NUNBOX32
+      case LDefinition::TYPE:
+      case LDefinition::PAYLOAD:
+#else
+      case LDefinition::BOX:
+#endif
+      case LDefinition::GENERAL:
+      case LDefinition::STACKRESULTS:
+        moveType = MoveOp::GENERAL;
+        break;
+      case LDefinition::INT32:
+        moveType = MoveOp::INT32;
+        break;
+      case LDefinition::FLOAT32:
+        moveType = MoveOp::FLOAT32;
+        break;
+      case LDefinition::DOUBLE:
+        moveType = MoveOp::DOUBLE;
+        break;
+      case LDefinition::SIMD128:
+        moveType = MoveOp::SIMD128;
+        break;
+      default:
+        MOZ_CRASH("Unexpected move type");
+    }
+
+    masm.propagateOOM(
+        resolver.addMove(toMoveOperand(from), toMoveOperand(to), moveType));
+  }
+
+  masm.propagateOOM(resolver.resolve());
+  if (masm.oom()) {
+    return;
+  }
+
+  MoveEmitter emitter(masm);
+
+#ifdef JS_CODEGEN_X86
+  if (group->maybeScratchRegister().isGeneralReg()) {
+    emitter.setScratchRegister(
+        group->maybeScratchRegister().toGeneralReg()->reg());
+  } else {
+    resolver.sortMemoryToMemoryMoves();
+  }
+#endif
+
+  emitter.emit(resolver);
+  emitter.finish();
+}
+
+void CodeGenerator::visitInteger(LInteger* lir) {
+  masm.move32(Imm32(lir->getValue()), ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitInteger64(LInteger64* lir) {
+  masm.move64(Imm64(lir->getValue()), ToOutRegister64(lir));
+}
+
+void CodeGenerator::visitPointer(LPointer* lir) {
+  masm.movePtr(ImmGCPtr(lir->gcptr()), ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitNurseryObject(LNurseryObject* lir) {
+  Register output = ToRegister(lir->output());
+  uint32_t nurseryIndex = lir->mir()->nurseryIndex();
+
+  // Load a pointer to the entry in IonScript's nursery objects list.
+  CodeOffset label = masm.movWithPatch(ImmWord(uintptr_t(-1)), output);
+  masm.propagateOOM(ionNurseryObjectLabels_.emplaceBack(label, nurseryIndex));
+
+  // Load the JSObject*.
+  masm.loadPtr(Address(output, 0), output);
+}
+
+void CodeGenerator::visitKeepAliveObject(LKeepAliveObject* lir) {
+  // No-op.
+}
+
+void CodeGenerator::visitSlots(LSlots* lir) {
+  Address slots(ToRegister(lir->object()), NativeObject::offsetOfSlots());
+  masm.loadPtr(slots, ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitLoadDynamicSlotV(LLoadDynamicSlotV* lir) {
+  ValueOperand dest = ToOutValue(lir);
+  Register base = ToRegister(lir->input());
+  int32_t offset = lir->mir()->slot() * sizeof(js::Value);
+
+  masm.loadValue(Address(base, offset), dest);
+}
+
+static ConstantOrRegister ToConstantOrRegister(const LAllocation* value,
+                                               MIRType valueType) {
+  if (value->isConstant()) {
+    return ConstantOrRegister(value->toConstant()->toJSValue());
+  }
+  return TypedOrValueRegister(valueType, ToAnyRegister(value));
+}
+
+void CodeGenerator::visitStoreDynamicSlotT(LStoreDynamicSlotT* lir) {
+  Register base = ToRegister(lir->slots());
+  int32_t offset = lir->mir()->slot() * sizeof(js::Value);
+  Address dest(base, offset);
+
+  if (lir->mir()->needsBarrier()) {
+    emitPreBarrier(dest);
+  }
+
+  MIRType valueType = lir->mir()->value()->type();
+  ConstantOrRegister value = ToConstantOrRegister(lir->value(), valueType);
+  masm.storeUnboxedValue(value, valueType, dest, lir->mir()->slotType());
+}
+
+void CodeGenerator::visitStoreDynamicSlotV(LStoreDynamicSlotV* lir) {
+  Register base = ToRegister(lir->slots());
+  int32_t offset = lir->mir()->slot() * sizeof(Value);
+
+  const ValueOperand value = ToValue(lir, LStoreDynamicSlotV::Value);
+
+  if (lir->mir()->needsBarrier()) {
+    emitPreBarrier(Address(base, offset));
+  }
+
+  masm.storeValue(value, Address(base, offset));
+}
+
+void CodeGenerator::visitElements(LElements* lir) {
+  Address elements(ToRegister(lir->object()), NativeObject::offsetOfElements());
+  masm.loadPtr(elements, ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitFunctionEnvironment(LFunctionEnvironment* lir) {
+  Address environment(ToRegister(lir->function()),
+                      JSFunction::offsetOfEnvironment());
+  masm.loadPtr(environment, ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitHomeObject(LHomeObject* lir) {
+  Address homeObject(ToRegister(lir->function()),
+                     FunctionExtended::offsetOfMethodHomeObjectSlot());
+#ifdef DEBUG
+  Label isObject;
+  masm.branchTestObject(Assembler::Equal, homeObject, &isObject);
+  masm.assumeUnreachable("[[HomeObject]] must be Object");
+  masm.bind(&isObject);
+#endif
+  masm.unboxObject(homeObject, ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitHomeObjectSuperBase(LHomeObjectSuperBase* lir) {
+  Register homeObject = ToRegister(lir->homeObject());
+  Register output = ToRegister(lir->output());
+
+  using Fn = bool (*)(JSContext*);
+  OutOfLineCode* ool =
+      oolCallVM<Fn, ThrowHomeObjectNotObject>(lir, ArgList(), StoreNothing());
+
+  masm.loadObjProto(homeObject, output);
+
+#ifdef DEBUG
+  // We won't encounter a lazy proto, because the prototype is guaranteed to
+  // either be a JSFunction or a PlainObject, and only proxy objects can have a
+  // lazy proto.
+  MOZ_ASSERT(uintptr_t(TaggedProto::LazyProto) == 1);
+
+  Label proxyCheckDone;
+  masm.branchPtr(Assembler::NotEqual, output, ImmWord(1), &proxyCheckDone);
+  masm.assumeUnreachable("Unexpected lazy proto in JSOp::SuperBase");
+  masm.bind(&proxyCheckDone);
+#endif
+
+  masm.branchPtr(Assembler::Equal, output, ImmWord(0), ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewLexicalEnvironmentObject(
+    LNewLexicalEnvironmentObject* lir) {
+  pushArg(Imm32(gc::DefaultHeap));
+  pushArg(ToRegister(lir->enclosing()));
+  pushArg(ImmGCPtr(lir->mir()->scope()));
+
+  using Fn = LexicalEnvironmentObject* (*)(JSContext*, Handle<LexicalScope*>,
+                                           HandleObject, gc::InitialHeap);
+  callVM<Fn, LexicalEnvironmentObject::create>(lir);
+}
+
+void CodeGenerator::visitCopyLexicalEnvironmentObject(
+    LCopyLexicalEnvironmentObject* lir) {
+  pushArg(Imm32(lir->mir()->copySlots()));
+  pushArg(ToRegister(lir->env()));
+
+  using Fn = JSObject* (*)(JSContext*, HandleObject, bool);
+  callVM<Fn, jit::CopyLexicalEnvironmentObject>(lir);
+}
+
+void CodeGenerator::visitGuardShape(LGuardShape* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToTempRegisterOrInvalid(guard->temp());
+  Label bail;
+  masm.branchTestObjShape(Assembler::NotEqual, obj, guard->mir()->shape(), temp,
+                          obj, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardProto(LGuardProto* guard) {
+  Register obj = ToRegister(guard->object());
+  Register expected = ToRegister(guard->expected());
+  Register temp = ToRegister(guard->temp());
+
+  masm.loadObjProto(obj, temp);
+
+  Label bail;
+  masm.branchPtr(Assembler::NotEqual, temp, expected, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardNullProto(LGuardNullProto* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  masm.loadObjProto(obj, temp);
+
+  Label bail;
+  masm.branchTestPtr(Assembler::NonZero, temp, temp, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardIsNativeObject(LGuardIsNativeObject* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  Label bail;
+  masm.branchIfNonNativeObj(obj, temp, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardIsProxy(LGuardIsProxy* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  Label bail;
+  masm.branchTestObjectIsProxy(false, obj, temp, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardIsNotProxy(LGuardIsNotProxy* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  Label bail;
+  masm.branchTestObjectIsProxy(true, obj, temp, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardIsNotDOMProxy(LGuardIsNotDOMProxy* guard) {
+  Register proxy = ToRegister(guard->proxy());
+  Register temp = ToRegister(guard->temp());
+
+  Label bail;
+  masm.branchTestProxyHandlerFamily(Assembler::Equal, proxy, temp,
+                                    GetDOMProxyHandlerFamily(), &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitProxyGet(LProxyGet* lir) {
+  Register proxy = ToRegister(lir->proxy());
+  Register temp = ToRegister(lir->temp());
+
+  pushArg(lir->mir()->id(), temp);
+  pushArg(proxy);
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandleId, MutableHandleValue);
+  callVM<Fn, ProxyGetProperty>(lir);
+}
+
+void CodeGenerator::visitProxyGetByValue(LProxyGetByValue* lir) {
+  Register proxy = ToRegister(lir->proxy());
+  ValueOperand idVal = ToValue(lir, LProxyGetByValue::IdIndex);
+
+  pushArg(idVal);
+  pushArg(proxy);
+
+  using Fn =
+      bool (*)(JSContext*, HandleObject, HandleValue, MutableHandleValue);
+  callVM<Fn, ProxyGetPropertyByValue>(lir);
+}
+
+void CodeGenerator::visitProxyHasProp(LProxyHasProp* lir) {
+  Register proxy = ToRegister(lir->proxy());
+  ValueOperand idVal = ToValue(lir, LProxyHasProp::IdIndex);
+
+  pushArg(idVal);
+  pushArg(proxy);
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandleValue, bool*);
+  if (lir->mir()->hasOwn()) {
+    callVM<Fn, ProxyHasOwn>(lir);
+  } else {
+    callVM<Fn, ProxyHas>(lir);
+  }
+}
+
+void CodeGenerator::visitProxySet(LProxySet* lir) {
+  Register proxy = ToRegister(lir->proxy());
+  ValueOperand rhs = ToValue(lir, LProxySet::RhsIndex);
+  Register temp = ToRegister(lir->temp());
+
+  pushArg(Imm32(lir->mir()->strict()));
+  pushArg(rhs);
+  pushArg(lir->mir()->id(), temp);
+  pushArg(proxy);
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandleId, HandleValue, bool);
+  callVM<Fn, ProxySetProperty>(lir);
+}
+
+void CodeGenerator::visitProxySetByValue(LProxySetByValue* lir) {
+  Register proxy = ToRegister(lir->proxy());
+  ValueOperand idVal = ToValue(lir, LProxySetByValue::IdIndex);
+  ValueOperand rhs = ToValue(lir, LProxySetByValue::RhsIndex);
+
+  pushArg(Imm32(lir->mir()->strict()));
+  pushArg(rhs);
+  pushArg(idVal);
+  pushArg(proxy);
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandleValue, HandleValue, bool);
+  callVM<Fn, ProxySetPropertyByValue>(lir);
+}
+
+void CodeGenerator::visitCallSetArrayLength(LCallSetArrayLength* lir) {
+  Register obj = ToRegister(lir->obj());
+  ValueOperand rhs = ToValue(lir, LCallSetArrayLength::RhsIndex);
+
+  pushArg(Imm32(lir->mir()->strict()));
+  pushArg(rhs);
+  pushArg(obj);
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandleValue, bool);
+  callVM<Fn, jit::SetArrayLength>(lir);
+}
+
+void CodeGenerator::visitMegamorphicLoadSlot(LMegamorphicLoadSlot* lir) {
+  Register obj = ToRegister(lir->object());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  Register temp3 = ToRegister(lir->temp3());
+  ValueOperand output = ToOutValue(lir);
+
+  Label bail;
+  masm.branchIfNonNativeObj(obj, temp1, &bail);
+
+  masm.pushValue(UndefinedValue());
+  masm.moveStackPtrTo(temp3);
+
+  using Fn =
+      bool (*)(JSContext * cx, JSObject * obj, PropertyName * name, Value * vp);
+  masm.setupUnalignedABICall(temp1);
+  masm.loadJSContext(temp1);
+  masm.passABIArg(temp1);
+  masm.passABIArg(obj);
+  masm.movePtr(ImmGCPtr(lir->mir()->name()), temp2);
+  masm.passABIArg(temp2);
+  masm.passABIArg(temp3);
+
+  masm.callWithABI<Fn, GetNativeDataPropertyPure>();
+
+  MOZ_ASSERT(!output.aliases(ReturnReg));
+  masm.popValue(output);
+
+  masm.branchIfFalseBool(ReturnReg, &bail);
+
+  if (JitOptions.spectreJitToCxxCalls) {
+    masm.speculationBarrier();
+  }
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitMegamorphicLoadSlotByValue(
+    LMegamorphicLoadSlotByValue* lir) {
+  Register obj = ToRegister(lir->object());
+  ValueOperand idVal = ToValue(lir, LMegamorphicLoadSlotByValue::IdIndex);
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  ValueOperand output = ToOutValue(lir);
+
+  Label bail;
+  masm.branchIfNonNativeObj(obj, temp1, &bail);
+
+  // idVal will be in vp[0], result will be stored in vp[1].
+  masm.subFromStackPtr(Imm32(sizeof(Value)));
+  masm.pushValue(idVal);
+  masm.moveStackPtrTo(temp1);
+
+  using Fn = bool (*)(JSContext * cx, JSObject * obj, Value * vp);
+  masm.setupUnalignedABICall(temp2);
+  masm.loadJSContext(temp2);
+  masm.passABIArg(temp2);
+  masm.passABIArg(obj);
+  masm.passABIArg(temp1);
+  masm.callWithABI<Fn, GetNativeDataPropertyByValuePure>();
+
+  MOZ_ASSERT(!idVal.aliases(temp1));
+  masm.mov(ReturnReg, temp1);
+  masm.popValue(idVal);
+
+  Label ok;
+  masm.branchIfTrueBool(temp1, &ok);
+  masm.addToStackPtr(Imm32(sizeof(Value)));  // Discard result Value.
+  masm.jump(&bail);
+
+  masm.bind(&ok);
+  if (JitOptions.spectreJitToCxxCalls) {
+    masm.speculationBarrier();
+  }
+  masm.popValue(output);
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitMegamorphicStoreSlot(LMegamorphicStoreSlot* lir) {
+  Register obj = ToRegister(lir->object());
+  ValueOperand rhs = ToValue(lir, LMegamorphicStoreSlot::RhsIndex);
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  Register temp3 = ToRegister(lir->temp3());
+
+  masm.pushValue(rhs);
+  masm.moveStackPtrTo(temp1);
+
+  using Fn = bool (*)(JSContext * cx, JSObject * obj, PropertyName * name,
+                      Value * val);
+  masm.setupUnalignedABICall(temp2);
+  masm.loadJSContext(temp2);
+  masm.passABIArg(temp2);
+  masm.passABIArg(obj);
+  masm.movePtr(ImmGCPtr(lir->mir()->name()), temp3);
+  masm.passABIArg(temp3);
+  masm.passABIArg(temp1);
+  masm.callWithABI<Fn, SetNativeDataPropertyPure>();
+
+  MOZ_ASSERT(!rhs.aliases(temp1));
+  masm.mov(ReturnReg, temp1);
+  masm.popValue(rhs);
+
+  Label bail;
+  masm.branchIfFalseBool(temp1, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitMegamorphicHasProp(LMegamorphicHasProp* lir) {
+  Register obj = ToRegister(lir->object());
+  ValueOperand idVal = ToValue(lir, LMegamorphicHasProp::IdIndex);
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  Register output = ToRegister(lir->output());
+
+  // idVal will be in vp[0], result will be stored in vp[1].
+  masm.subFromStackPtr(Imm32(sizeof(Value)));
+  masm.pushValue(idVal);
+  masm.moveStackPtrTo(temp1);
+
+  using Fn = bool (*)(JSContext * cx, JSObject * obj, Value * vp);
+  masm.setupUnalignedABICall(temp2);
+  masm.loadJSContext(temp2);
+  masm.passABIArg(temp2);
+  masm.passABIArg(obj);
+  masm.passABIArg(temp1);
+  if (lir->mir()->hasOwn()) {
+    masm.callWithABI<Fn, HasNativeDataPropertyPure<true>>();
+  } else {
+    masm.callWithABI<Fn, HasNativeDataPropertyPure<false>>();
+  }
+
+  MOZ_ASSERT(!idVal.aliases(temp1));
+  masm.mov(ReturnReg, temp1);
+  masm.popValue(idVal);
+
+  Label bail, ok;
+  masm.branchIfTrueBool(temp1, &ok);
+  masm.addToStackPtr(Imm32(sizeof(Value)));  // Discard result Value.
+  masm.jump(&bail);
+
+  masm.bind(&ok);
+  masm.unboxBoolean(Address(masm.getStackPointer(), 0), output);
+  masm.addToStackPtr(Imm32(sizeof(Value)));
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardIsNotArrayBufferMaybeShared(
+    LGuardIsNotArrayBufferMaybeShared* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  Label bail;
+  masm.loadObjClassUnsafe(obj, temp);
+  masm.branchPtr(Assembler::Equal, temp, ImmPtr(&ArrayBufferObject::class_),
+                 &bail);
+  masm.branchPtr(Assembler::Equal, temp,
+                 ImmPtr(&SharedArrayBufferObject::class_), &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardIsTypedArray(LGuardIsTypedArray* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  Label bail;
+  masm.loadObjClassUnsafe(obj, temp);
+  masm.branchIfClassIsNotTypedArray(temp, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardObjectGroup(LGuardObjectGroup* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToTempRegisterOrInvalid(guard->temp());
+  Assembler::Condition cond =
+      guard->mir()->bailOnEquality() ? Assembler::Equal : Assembler::NotEqual;
+  Label bail;
+  masm.branchTestObjGroup(cond, obj, guard->mir()->group(), temp, obj, &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardObjectIdentity(LGuardObjectIdentity* guard) {
+  Register input = ToRegister(guard->input());
+  Register expected = ToRegister(guard->expected());
+
+  Assembler::Condition cond =
+      guard->mir()->bailOnEquality() ? Assembler::Equal : Assembler::NotEqual;
+  bailoutCmpPtr(cond, input, expected, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardSpecificFunction(LGuardSpecificFunction* guard) {
+  Register input = ToRegister(guard->input());
+  Register expected = ToRegister(guard->expected());
+
+  bailoutCmpPtr(Assembler::NotEqual, input, expected, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardSpecificAtom(LGuardSpecificAtom* guard) {
+  Register str = ToRegister(guard->str());
+  Register scratch = ToRegister(guard->temp());
+
+  LiveRegisterSet volatileRegs = liveVolatileRegs(guard);
+  volatileRegs.takeUnchecked(scratch);
+
+  Label bail;
+  masm.guardSpecificAtom(str, guard->mir()->atom(), scratch, volatileRegs,
+                         &bail);
+  bailoutFrom(&bail, guard->snapshot());
+}
+
+void CodeGenerator::visitGuardSpecificSymbol(LGuardSpecificSymbol* guard) {
+  Register symbol = ToRegister(guard->symbol());
+
+  bailoutCmpPtr(Assembler::NotEqual, symbol, ImmGCPtr(guard->mir()->expected()),
+                guard->snapshot());
+}
+
+void CodeGenerator::visitGuardStringToIndex(LGuardStringToIndex* lir) {
+  Register str = ToRegister(lir->string());
+  Register output = ToRegister(lir->output());
+
+  Label bail, vmCall, done;
+  masm.loadStringIndexValue(str, output, &vmCall);
+  masm.jump(&done);
+
+  {
+    masm.bind(&vmCall);
+
+    LiveRegisterSet volatileRegs = liveVolatileRegs(lir);
+    volatileRegs.takeUnchecked(output);
+    masm.PushRegsInMask(volatileRegs);
+
+    using Fn = int32_t (*)(JSString * str);
+    masm.setupUnalignedABICall(output);
+    masm.passABIArg(str);
+    masm.callWithABI<Fn, GetIndexFromString>();
+    masm.storeCallInt32Result(output);
+
+    masm.PopRegsInMask(volatileRegs);
+
+    // GetIndexFromString returns a negative value on failure.
+    masm.branchTest32(Assembler::Signed, output, output, &bail);
+  }
+
+  masm.bind(&done);
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardStringToInt32(LGuardStringToInt32* lir) {
+  Register str = ToRegister(lir->string());
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+
+  LiveRegisterSet volatileRegs = liveVolatileRegs(lir);
+
+  Label bail;
+  masm.guardStringToInt32(str, output, temp, volatileRegs, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardStringToDouble(LGuardStringToDouble* lir) {
+  Register str = ToRegister(lir->string());
+  FloatRegister output = ToFloatRegister(lir->output());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+
+  Label bail, vmCall, done;
+  // Use indexed value as fast path if possible.
+  masm.loadStringIndexValue(str, temp1, &vmCall);
+  masm.convertInt32ToDouble(temp1, output);
+  masm.jump(&done);
+  {
+    masm.bind(&vmCall);
+
+    // Reserve stack for holding the result value of the call.
+    masm.reserveStack(sizeof(double));
+    masm.moveStackPtrTo(temp1);
+
+    LiveRegisterSet volatileRegs = liveVolatileRegs(lir);
+    volatileRegs.takeUnchecked(temp1);
+    volatileRegs.takeUnchecked(temp2);
+    masm.PushRegsInMask(volatileRegs);
+
+    using Fn = bool (*)(JSContext * cx, JSString * str, double* result);
+    masm.setupUnalignedABICall(temp2);
+    masm.loadJSContext(temp2);
+    masm.passABIArg(temp2);
+    masm.passABIArg(str);
+    masm.passABIArg(temp1);
+    masm.callWithABI<Fn, StringToNumberPure>();
+    masm.mov(ReturnReg, temp1);
+
+    masm.PopRegsInMask(volatileRegs);
+
+    Label ok;
+    masm.branchIfTrueBool(temp1, &ok);
+    {
+      // OOM path, recovered by StringToNumberPure.
+      //
+      // Use addToStackPtr instead of freeStack as freeStack tracks stack height
+      // flow-insensitively, and using it here would confuse the stack height
+      // tracking.
+      masm.addToStackPtr(Imm32(sizeof(double)));
+      masm.jump(&bail);
+    }
+    masm.bind(&ok);
+    masm.Pop(output);
+  }
+  masm.bind(&done);
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardNoDenseElements(LGuardNoDenseElements* guard) {
+  Register obj = ToRegister(guard->input());
+  Register temp = ToRegister(guard->temp());
+
+  // Load obj->elements.
+  masm.loadPtr(Address(obj, NativeObject::offsetOfElements()), temp);
+
+  // Make sure there are no dense elements.
+  Address initLength(temp, ObjectElements::offsetOfInitializedLength());
+  bailoutCmp32(Assembler::NotEqual, initLength, Imm32(0), guard->snapshot());
+}
+
+void CodeGenerator::visitBooleanToInt64(LBooleanToInt64* lir) {
+  Register input = ToRegister(lir->input());
+  Register64 output = ToOutRegister64(lir);
+
+  masm.move32To64ZeroExtend(input, output);
+}
+
+void CodeGenerator::emitStringToInt64(LInstruction* lir, Register input,
+                                      Register64 output) {
+  Register temp = output.scratchReg();
+
+  saveLive(lir);
+
+  masm.reserveStack(sizeof(uint64_t));
+  masm.moveStackPtrTo(temp);
+  pushArg(temp);
+  pushArg(input);
+
+  using Fn = bool (*)(JSContext*, HandleString, uint64_t*);
+  callVM<Fn, DoStringToInt64>(lir);
+
+  masm.load64(Address(masm.getStackPointer(), 0), output);
+  masm.freeStack(sizeof(uint64_t));
+
+  restoreLiveIgnore(lir, StoreValueTo(output).clobbered());
+}
+
+void CodeGenerator::visitStringToInt64(LStringToInt64* lir) {
+  Register input = ToRegister(lir->input());
+  Register64 output = ToOutRegister64(lir);
+
+  emitStringToInt64(lir, input, output);
+}
+
+void CodeGenerator::visitValueToInt64(LValueToInt64* lir) {
+  ValueOperand input = ToValue(lir, LValueToInt64::Input);
+  Register temp = ToRegister(lir->temp());
+  Register64 output = ToOutRegister64(lir);
+
+  int checks = 3;
+
+  Label fail, done;
+  // Jump to fail if this is the last check and we fail it,
+  // otherwise to the next test.
+  auto emitTestAndUnbox = [&](auto testAndUnbox) {
+    MOZ_ASSERT(checks > 0);
+
+    checks--;
+    Label notType;
+    Label* target = checks ? &notType : &fail;
+
+    testAndUnbox(target);
+
+    if (checks) {
+      masm.jump(&done);
+      masm.bind(&notType);
+    }
+  };
+
+  Register tag = masm.extractTag(input, temp);
+
+  // BigInt.
+  emitTestAndUnbox([&](Label* target) {
+    masm.branchTestBigInt(Assembler::NotEqual, tag, target);
+    masm.unboxBigInt(input, temp);
+    masm.loadBigInt64(temp, output);
+  });
+
+  // Boolean
+  emitTestAndUnbox([&](Label* target) {
+    masm.branchTestBoolean(Assembler::NotEqual, tag, target);
+    masm.unboxBoolean(input, temp);
+    masm.move32To64ZeroExtend(temp, output);
+  });
+
+  // String
+  emitTestAndUnbox([&](Label* target) {
+    masm.branchTestString(Assembler::NotEqual, tag, target);
+    masm.unboxString(input, temp);
+    emitStringToInt64(lir, temp, output);
+  });
+
+  MOZ_ASSERT(checks == 0);
+
+  bailoutFrom(&fail, lir->snapshot());
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitTruncateBigIntToInt64(LTruncateBigIntToInt64* lir) {
+  Register operand = ToRegister(lir->input());
+  Register64 output = ToOutRegister64(lir);
+
+  masm.loadBigInt64(operand, output);
+}
+
+void CodeGenerator::emitCreateBigInt(LInstruction* lir, Scalar::Type type,
+                                     Register64 input, Register output,
+                                     Register maybeTemp) {
+#if JS_BITS_PER_WORD == 32
+  using Fn = BigInt* (*)(JSContext*, uint32_t, uint32_t);
+  auto args = ArgList(input.low, input.high);
+#else
+  using Fn = BigInt* (*)(JSContext*, uint64_t);
+  auto args = ArgList(input);
+#endif
+
+  OutOfLineCode* ool;
+  if (type == Scalar::BigInt64) {
+    ool = oolCallVM<Fn, jit::CreateBigIntFromInt64>(lir, args,
+                                                    StoreRegisterTo(output));
+  } else {
+    MOZ_ASSERT(type == Scalar::BigUint64);
+    ool = oolCallVM<Fn, jit::CreateBigIntFromUint64>(lir, args,
+                                                     StoreRegisterTo(output));
+  }
+
+  if (maybeTemp != InvalidReg) {
+    masm.newGCBigInt(output, maybeTemp, ool->entry(), bigIntsCanBeInNursery());
+  } else {
+    AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+    regs.take(input);
+    regs.take(output);
+
+    Register temp = regs.takeAny();
+
+    masm.push(temp);
+
+    Label fail, ok;
+    masm.newGCBigInt(output, temp, &fail, bigIntsCanBeInNursery());
+    masm.pop(temp);
+    masm.jump(&ok);
+    masm.bind(&fail);
+    masm.pop(temp);
+    masm.jump(ool->entry());
+    masm.bind(&ok);
+  }
+  masm.initializeBigInt64(type, output, input);
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitInt64ToBigInt(LInt64ToBigInt* lir) {
+  Register64 input = ToRegister64(lir->input());
+  Register temp = ToRegister(lir->temp());
+  Register output = ToRegister(lir->output());
+
+  emitCreateBigInt(lir, Scalar::BigInt64, input, output, temp);
+}
+
+void CodeGenerator::visitGuardValue(LGuardValue* lir) {
+  ValueOperand input = ToValue(lir, LGuardValue::Input);
+  Value expected = lir->mir()->expected();
+  Label bail;
+  masm.branchTestValue(Assembler::NotEqual, input, expected, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardNotOptimizedArguments(
+    LGuardNotOptimizedArguments* lir) {
+  ValueOperand input = ToValue(lir, LGuardNotOptimizedArguments::Input);
+  Label bail;
+  masm.branchTestValue(Assembler::Equal, input,
+                       MagicValue(JS_OPTIMIZED_ARGUMENTS), &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardNullOrUndefined(LGuardNullOrUndefined* lir) {
+  ValueOperand input = ToValue(lir, LGuardNullOrUndefined::Input);
+
+  ScratchTagScope tag(masm, input);
+  masm.splitTagForTest(input, tag);
+
+  Label done;
+  masm.branchTestNull(Assembler::Equal, tag, &done);
+
+  Label bail;
+  masm.branchTestUndefined(Assembler::NotEqual, tag, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitGuardFunctionFlags(LGuardFunctionFlags* lir) {
+  Register function = ToRegister(lir->function());
+
+  Label bail;
+  if (uint16_t flags = lir->mir()->expectedFlags()) {
+    masm.branchTestFunctionFlags(function, flags, Assembler::Zero, &bail);
+  }
+  if (uint16_t flags = lir->mir()->unexpectedFlags()) {
+    masm.branchTestFunctionFlags(function, flags, Assembler::NonZero, &bail);
+  }
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardFunctionIsNonBuiltinCtor(
+    LGuardFunctionIsNonBuiltinCtor* lir) {
+  Register function = ToRegister(lir->function());
+  Register temp = ToRegister(lir->temp());
+
+  Label bail;
+  masm.branchIfNotFunctionIsNonBuiltinCtor(function, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardFunctionKind(LGuardFunctionKind* lir) {
+  Register function = ToRegister(lir->function());
+  Register temp = ToRegister(lir->temp());
+
+  Assembler::Condition cond =
+      lir->mir()->bailOnEquality() ? Assembler::Equal : Assembler::NotEqual;
+
+  Label bail;
+  masm.branchFunctionKind(cond, lir->mir()->expected(), function, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardFunctionScript(LGuardFunctionScript* lir) {
+  Register function = ToRegister(lir->function());
+
+  Label bail;
+  Address scriptAddr(function, JSFunction::offsetOfBaseScript());
+  masm.branchPtr(Assembler::NotEqual, scriptAddr,
+                 ImmGCPtr(lir->mir()->expected()), &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+// Out-of-line path to update the store buffer.
+class OutOfLineCallPostWriteBarrier : public OutOfLineCodeBase<CodeGenerator> {
+  LInstruction* lir_;
+  const LAllocation* object_;
+
+ public:
+  OutOfLineCallPostWriteBarrier(LInstruction* lir, const LAllocation* object)
+      : lir_(lir), object_(object) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineCallPostWriteBarrier(this);
+  }
+
+  LInstruction* lir() const { return lir_; }
+  const LAllocation* object() const { return object_; }
+};
+
+static void EmitStoreBufferCheckForConstant(MacroAssembler& masm,
+                                            const gc::TenuredCell* cell,
+                                            AllocatableGeneralRegisterSet& regs,
+                                            Label* exit, Label* callVM) {
+  Register temp = regs.takeAny();
+
+  gc::Arena* arena = cell->arena();
+
+  Register cells = temp;
+  masm.loadPtr(AbsoluteAddress(&arena->bufferedCells()), cells);
+
+  size_t index = gc::ArenaCellSet::getCellIndex(cell);
+  size_t word;
+  uint32_t mask;
+  gc::ArenaCellSet::getWordIndexAndMask(index, &word, &mask);
+  size_t offset = gc::ArenaCellSet::offsetOfBits() + word * sizeof(uint32_t);
+
+  masm.branchTest32(Assembler::NonZero, Address(cells, offset), Imm32(mask),
+                    exit);
+
+  // Check whether this is the sentinel set and if so call the VM to allocate
+  // one for this arena.
+  masm.branchPtr(Assembler::Equal,
+                 Address(cells, gc::ArenaCellSet::offsetOfArena()),
+                 ImmPtr(nullptr), callVM);
+
+  // Add the cell to the set.
+  masm.or32(Imm32(mask), Address(cells, offset));
+  masm.jump(exit);
+
+  regs.add(temp);
+}
+
+static void EmitPostWriteBarrier(MacroAssembler& masm, CompileRuntime* runtime,
+                                 Register objreg, JSObject* maybeConstant,
+                                 bool isGlobal,
+                                 AllocatableGeneralRegisterSet& regs) {
+  MOZ_ASSERT_IF(isGlobal, maybeConstant);
+
+  Label callVM;
+  Label exit;
+
+  // We already have a fast path to check whether a global is in the store
+  // buffer.
+  if (!isGlobal && maybeConstant) {
+    EmitStoreBufferCheckForConstant(masm, &maybeConstant->asTenured(), regs,
+                                    &exit, &callVM);
+  }
+
+  // Call into the VM to barrier the write.
+  masm.bind(&callVM);
+
+  Register runtimereg = regs.takeAny();
+  masm.mov(ImmPtr(runtime), runtimereg);
+
+  masm.setupUnalignedABICall(regs.takeAny());
+  masm.passABIArg(runtimereg);
+  masm.passABIArg(objreg);
+  if (isGlobal) {
+    using Fn = void (*)(JSRuntime * rt, GlobalObject * obj);
+    masm.callWithABI<Fn, PostGlobalWriteBarrier>();
+  } else {
+    using Fn = void (*)(JSRuntime * rt, js::gc::Cell * obj);
+    masm.callWithABI<Fn, PostWriteBarrier>();
+  }
+
+  masm.bind(&exit);
+}
+
+void CodeGenerator::emitPostWriteBarrier(const LAllocation* obj) {
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::Volatile());
+
+  Register objreg;
+  JSObject* object = nullptr;
+  bool isGlobal = false;
+  if (obj->isConstant()) {
+    object = &obj->toConstant()->toObject();
+    isGlobal = isGlobalObject(object);
+    objreg = regs.takeAny();
+    masm.movePtr(ImmGCPtr(object), objreg);
+  } else {
+    objreg = ToRegister(obj);
+    regs.takeUnchecked(objreg);
+  }
+
+  EmitPostWriteBarrier(masm, gen->runtime, objreg, object, isGlobal, regs);
+}
+
+void CodeGenerator::emitPostWriteBarrier(Register objreg) {
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::Volatile());
+  regs.takeUnchecked(objreg);
+  EmitPostWriteBarrier(masm, gen->runtime, objreg, nullptr, false, regs);
+}
+
+void CodeGenerator::visitOutOfLineCallPostWriteBarrier(
+    OutOfLineCallPostWriteBarrier* ool) {
+  saveLiveVolatile(ool->lir());
+  const LAllocation* obj = ool->object();
+  emitPostWriteBarrier(obj);
+  restoreLiveVolatile(ool->lir());
+
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::maybeEmitGlobalBarrierCheck(const LAllocation* maybeGlobal,
+                                                OutOfLineCode* ool) {
+  // Check whether an object is a global that we have already barriered before
+  // calling into the VM.
+  //
+  // We only check for the script's global, not other globals within the same
+  // compartment, because we bake in a pointer to realm->globalWriteBarriered
+  // and doing that would be invalid for other realms because they could be
+  // collected before the Ion code is discarded.
+
+  if (!maybeGlobal->isConstant()) {
+    return;
+  }
+
+  JSObject* obj = &maybeGlobal->toConstant()->toObject();
+  if (gen->realm->maybeGlobal() != obj) {
+    return;
+  }
+
+  const uint32_t* addr = gen->realm->addressOfGlobalWriteBarriered();
+  masm.branch32(Assembler::NotEqual, AbsoluteAddress(addr), Imm32(0),
+                ool->rejoin());
+}
+
+template <class LPostBarrierType, MIRType nurseryType>
+void CodeGenerator::visitPostWriteBarrierCommon(LPostBarrierType* lir,
+                                                OutOfLineCode* ool) {
+  static_assert(NeedsPostBarrier(nurseryType));
+
+  addOutOfLineCode(ool, lir->mir());
+
+  Register temp = ToTempRegisterOrInvalid(lir->temp());
+
+  if (lir->object()->isConstant()) {
+    // Constant nursery objects cannot appear here, see
+    // LIRGenerator::visitPostWriteElementBarrier.
+    MOZ_ASSERT(!IsInsideNursery(&lir->object()->toConstant()->toObject()));
+  } else {
+    masm.branchPtrInNurseryChunk(Assembler::Equal, ToRegister(lir->object()),
+                                 temp, ool->rejoin());
+  }
+
+  maybeEmitGlobalBarrierCheck(lir->object(), ool);
+
+  Register value = ToRegister(lir->value());
+  if constexpr (nurseryType == MIRType::Object) {
+    MOZ_ASSERT(lir->mir()->value()->type() == MIRType::Object);
+  } else if constexpr (nurseryType == MIRType::String) {
+    MOZ_ASSERT(lir->mir()->value()->type() == MIRType::String);
+  } else {
+    static_assert(nurseryType == MIRType::BigInt);
+    MOZ_ASSERT(lir->mir()->value()->type() == MIRType::BigInt);
+  }
+  masm.branchPtrInNurseryChunk(Assembler::Equal, value, temp, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+template <class LPostBarrierType>
+void CodeGenerator::visitPostWriteBarrierCommonV(LPostBarrierType* lir,
+                                                 OutOfLineCode* ool) {
+  addOutOfLineCode(ool, lir->mir());
+
+  Register temp = ToTempRegisterOrInvalid(lir->temp());
+
+  if (lir->object()->isConstant()) {
+    // Constant nursery objects cannot appear here, see
+    // LIRGenerator::visitPostWriteElementBarrier.
+    MOZ_ASSERT(!IsInsideNursery(&lir->object()->toConstant()->toObject()));
+  } else {
+    masm.branchPtrInNurseryChunk(Assembler::Equal, ToRegister(lir->object()),
+                                 temp, ool->rejoin());
+  }
+
+  maybeEmitGlobalBarrierCheck(lir->object(), ool);
+
+  ValueOperand value = ToValue(lir, LPostBarrierType::Input);
+  masm.branchValueIsNurseryCell(Assembler::Equal, value, temp, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitPostWriteBarrierO(LPostWriteBarrierO* lir) {
+  auto ool = new (alloc()) OutOfLineCallPostWriteBarrier(lir, lir->object());
+  visitPostWriteBarrierCommon<LPostWriteBarrierO, MIRType::Object>(lir, ool);
+}
+
+void CodeGenerator::visitPostWriteBarrierS(LPostWriteBarrierS* lir) {
+  auto ool = new (alloc()) OutOfLineCallPostWriteBarrier(lir, lir->object());
+  visitPostWriteBarrierCommon<LPostWriteBarrierS, MIRType::String>(lir, ool);
+}
+
+void CodeGenerator::visitPostWriteBarrierBI(LPostWriteBarrierBI* lir) {
+  auto ool = new (alloc()) OutOfLineCallPostWriteBarrier(lir, lir->object());
+  visitPostWriteBarrierCommon<LPostWriteBarrierBI, MIRType::BigInt>(lir, ool);
+}
+
+void CodeGenerator::visitPostWriteBarrierV(LPostWriteBarrierV* lir) {
+  auto ool = new (alloc()) OutOfLineCallPostWriteBarrier(lir, lir->object());
+  visitPostWriteBarrierCommonV(lir, ool);
+}
+
+// Out-of-line path to update the store buffer.
+class OutOfLineCallPostWriteElementBarrier
+    : public OutOfLineCodeBase<CodeGenerator> {
+  LInstruction* lir_;
+  const LAllocation* object_;
+  const LAllocation* index_;
+
+ public:
+  OutOfLineCallPostWriteElementBarrier(LInstruction* lir,
+                                       const LAllocation* object,
+                                       const LAllocation* index)
+      : lir_(lir), object_(object), index_(index) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineCallPostWriteElementBarrier(this);
+  }
+
+  LInstruction* lir() const { return lir_; }
+
+  const LAllocation* object() const { return object_; }
+
+  const LAllocation* index() const { return index_; }
+};
+
+void CodeGenerator::visitOutOfLineCallPostWriteElementBarrier(
+    OutOfLineCallPostWriteElementBarrier* ool) {
+  saveLiveVolatile(ool->lir());
+
+  const LAllocation* obj = ool->object();
+  const LAllocation* index = ool->index();
+
+  Register objreg = obj->isConstant() ? InvalidReg : ToRegister(obj);
+  Register indexreg = ToRegister(index);
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::Volatile());
+  regs.takeUnchecked(indexreg);
+
+  if (obj->isConstant()) {
+    objreg = regs.takeAny();
+    masm.movePtr(ImmGCPtr(&obj->toConstant()->toObject()), objreg);
+  } else {
+    regs.takeUnchecked(objreg);
+  }
+
+  Register runtimereg = regs.takeAny();
+  using Fn = void (*)(JSRuntime * rt, JSObject * obj, int32_t index);
+  masm.setupUnalignedABICall(runtimereg);
+  masm.mov(ImmPtr(gen->runtime), runtimereg);
+  masm.passABIArg(runtimereg);
+  masm.passABIArg(objreg);
+  masm.passABIArg(indexreg);
+  masm.callWithABI<Fn, PostWriteElementBarrier<IndexInBounds::Maybe>>();
+
+  restoreLiveVolatile(ool->lir());
+
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitPostWriteElementBarrierO(
+    LPostWriteElementBarrierO* lir) {
+  auto ool = new (alloc())
+      OutOfLineCallPostWriteElementBarrier(lir, lir->object(), lir->index());
+  visitPostWriteBarrierCommon<LPostWriteElementBarrierO, MIRType::Object>(lir,
+                                                                          ool);
+}
+
+void CodeGenerator::visitPostWriteElementBarrierS(
+    LPostWriteElementBarrierS* lir) {
+  auto ool = new (alloc())
+      OutOfLineCallPostWriteElementBarrier(lir, lir->object(), lir->index());
+  visitPostWriteBarrierCommon<LPostWriteElementBarrierS, MIRType::String>(lir,
+                                                                          ool);
+}
+
+void CodeGenerator::visitPostWriteElementBarrierBI(
+    LPostWriteElementBarrierBI* lir) {
+  auto ool = new (alloc())
+      OutOfLineCallPostWriteElementBarrier(lir, lir->object(), lir->index());
+  visitPostWriteBarrierCommon<LPostWriteElementBarrierBI, MIRType::BigInt>(lir,
+                                                                           ool);
+}
+
+void CodeGenerator::visitPostWriteElementBarrierV(
+    LPostWriteElementBarrierV* lir) {
+  auto ool = new (alloc())
+      OutOfLineCallPostWriteElementBarrier(lir, lir->object(), lir->index());
+  visitPostWriteBarrierCommonV(lir, ool);
+}
+
+void CodeGenerator::visitCallNative(LCallNative* call) {
+  WrappedFunction* target = call->getSingleTarget();
+  MOZ_ASSERT(target);
+  MOZ_ASSERT(target->isNativeWithoutJitEntry());
+
+  int callargslot = call->argslot();
+  int unusedStack = StackOffsetOfPassedArg(callargslot);
+
+  // Registers used for callWithABI() argument-passing.
+  const Register argContextReg = ToRegister(call->getArgContextReg());
+  const Register argUintNReg = ToRegister(call->getArgUintNReg());
+  const Register argVpReg = ToRegister(call->getArgVpReg());
+
+  // Misc. temporary registers.
+  const Register tempReg = ToRegister(call->getTempReg());
+
+  DebugOnly<uint32_t> initialStack = masm.framePushed();
+
+  masm.checkStackAlignment();
+
+  // Native functions have the signature:
+  //  bool (*)(JSContext*, unsigned, Value* vp)
+  // Where vp[0] is space for an outparam, vp[1] is |this|, and vp[2] onward
+  // are the function arguments.
+
+  // Allocate space for the outparam, moving the StackPointer to what will be
+  // &vp[1].
+  masm.adjustStack(unusedStack);
+
+  // Push a Value containing the callee object: natives are allowed to access
+  // their callee before setting the return value. The StackPointer is moved
+  // to &vp[0].
+  masm.Push(ObjectValue(*target->rawNativeJSFunction()));
+
+  // Preload arguments into registers.
+  masm.loadJSContext(argContextReg);
+  masm.move32(Imm32(call->numActualArgs()), argUintNReg);
+  masm.moveStackPtrTo(argVpReg);
+
+  masm.Push(argUintNReg);
+
+  if (call->mir()->maybeCrossRealm()) {
+    masm.movePtr(ImmGCPtr(target->rawNativeJSFunction()), tempReg);
+    masm.switchToObjectRealm(tempReg, tempReg);
+  }
+
+  // Construct native exit frame.
+  uint32_t safepointOffset = masm.buildFakeExitFrame(tempReg);
+  masm.enterFakeExitFrameForNative(argContextReg, tempReg,
+                                   call->mir()->isConstructing());
+
+  markSafepointAt(safepointOffset, call);
+
+  if (JS::TraceLoggerSupported()) {
+    emitTracelogStartEvent(TraceLogger_Call);
+  }
+
+  // Construct and execute call.
+  masm.setupUnalignedABICall(tempReg);
+  masm.passABIArg(argContextReg);
+  masm.passABIArg(argUintNReg);
+  masm.passABIArg(argVpReg);
+  JSNative native = target->native();
+  if (call->ignoresReturnValue() && target->hasJitInfo()) {
+    const JSJitInfo* jitInfo = target->jitInfo();
+    if (jitInfo->type() == JSJitInfo::IgnoresReturnValueNative) {
+      native = jitInfo->ignoresReturnValueMethod;
+    }
+  }
+  masm.callWithABI(DynamicFunction<JSNative>(native), MoveOp::GENERAL,
+                   CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+  if (JS::TraceLoggerSupported()) {
+    emitTracelogStopEvent(TraceLogger_Call);
+  }
+
+  // Test for failure.
+  masm.branchIfFalseBool(ReturnReg, masm.failureLabel());
+
+  if (call->mir()->maybeCrossRealm()) {
+    masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+  }
+
+  // Load the outparam vp[0] into output register(s).
+  masm.loadValue(
+      Address(masm.getStackPointer(), NativeExitFrameLayout::offsetOfResult()),
+      JSReturnOperand);
+
+  // Until C++ code is instrumented against Spectre, prevent speculative
+  // execution from returning any private data.
+  if (JitOptions.spectreJitToCxxCalls && !call->mir()->ignoresReturnValue() &&
+      call->mir()->hasLiveDefUses()) {
+    masm.speculationBarrier();
+  }
+
+  // The next instruction is removing the footer of the exit frame, so there
+  // is no need for leaveFakeExitFrame.
+
+  // Move the StackPointer back to its original location, unwinding the native
+  // exit frame.
+  masm.adjustStack(NativeExitFrameLayout::Size() - unusedStack);
+  MOZ_ASSERT(masm.framePushed() == initialStack);
+}
+
+static void LoadDOMPrivate(MacroAssembler& masm, Register obj, Register priv,
+                           DOMObjectKind kind) {
+  // Load the value in DOM_OBJECT_SLOT for a native or proxy DOM object. This
+  // will be in the first slot but may be fixed or non-fixed.
+  MOZ_ASSERT(obj != priv);
+
+  // Check if it's a proxy.
+  Label isProxy, done;
+  if (kind == DOMObjectKind::Unknown) {
+    masm.branchTestObjectIsProxy(true, obj, priv, &isProxy);
+  }
+
+  if (kind != DOMObjectKind::Proxy) {
+    // If it's a native object, the value must be in a fixed slot.
+    masm.debugAssertObjHasFixedSlots(obj, priv);
+    masm.loadPrivate(Address(obj, NativeObject::getFixedSlotOffset(0)), priv);
+    if (kind == DOMObjectKind::Unknown) {
+      masm.jump(&done);
+    }
+  }
+
+  if (kind != DOMObjectKind::Native) {
+    masm.bind(&isProxy);
+#ifdef DEBUG
+    // Sanity check: it must be a DOM proxy.
+    Label isDOMProxy;
+    masm.branchTestProxyHandlerFamily(Assembler::Equal, obj, priv,
+                                      GetDOMProxyHandlerFamily(), &isDOMProxy);
+    masm.assumeUnreachable("Expected a DOM proxy");
+    masm.bind(&isDOMProxy);
+#endif
+    masm.loadPtr(Address(obj, ProxyObject::offsetOfReservedSlots()), priv);
+    masm.loadPrivate(
+        Address(priv, js::detail::ProxyReservedSlots::offsetOfSlot(0)), priv);
+  }
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitCallDOMNative(LCallDOMNative* call) {
+  WrappedFunction* target = call->getSingleTarget();
+  MOZ_ASSERT(target);
+  MOZ_ASSERT(target->isNativeWithoutJitEntry());
+  MOZ_ASSERT(target->hasJitInfo());
+  MOZ_ASSERT(call->mir()->isCallDOMNative());
+
+  int callargslot = call->argslot();
+  int unusedStack = StackOffsetOfPassedArg(callargslot);
+
+  // Registers used for callWithABI() argument-passing.
+  const Register argJSContext = ToRegister(call->getArgJSContext());
+  const Register argObj = ToRegister(call->getArgObj());
+  const Register argPrivate = ToRegister(call->getArgPrivate());
+  const Register argArgs = ToRegister(call->getArgArgs());
+
+  DebugOnly<uint32_t> initialStack = masm.framePushed();
+
+  masm.checkStackAlignment();
+
+  // DOM methods have the signature:
+  //  bool (*)(JSContext*, HandleObject, void* private, const
+  //  JSJitMethodCallArgs& args)
+  // Where args is initialized from an argc and a vp, vp[0] is space for an
+  // outparam and the callee, vp[1] is |this|, and vp[2] onward are the
+  // function arguments.  Note that args stores the argv, not the vp, and
+  // argv == vp + 2.
+
+  // Nestle the stack up against the pushed arguments, leaving StackPointer at
+  // &vp[1]
+  masm.adjustStack(unusedStack);
+  // argObj is filled with the extracted object, then returned.
+  Register obj = masm.extractObject(Address(masm.getStackPointer(), 0), argObj);
+  MOZ_ASSERT(obj == argObj);
+
+  // Push a Value containing the callee object: natives are allowed to access
+  // their callee before setting the return value. After this the StackPointer
+  // points to &vp[0].
+  masm.Push(ObjectValue(*target->rawNativeJSFunction()));
+
+  // Now compute the argv value.  Since StackPointer is pointing to &vp[0] and
+  // argv is &vp[2] we just need to add 2*sizeof(Value) to the current
+  // StackPointer.
+  static_assert(JSJitMethodCallArgsTraits::offsetOfArgv == 0);
+  static_assert(JSJitMethodCallArgsTraits::offsetOfArgc ==
+                IonDOMMethodExitFrameLayoutTraits::offsetOfArgcFromArgv);
+  masm.computeEffectiveAddress(
+      Address(masm.getStackPointer(), 2 * sizeof(Value)), argArgs);
+
+  LoadDOMPrivate(masm, obj, argPrivate,
+                 static_cast<MCallDOMNative*>(call->mir())->objectKind());
+
+  // Push argc from the call instruction into what will become the IonExitFrame
+  masm.Push(Imm32(call->numActualArgs()));
+
+  // Push our argv onto the stack
+  masm.Push(argArgs);
+  // And store our JSJitMethodCallArgs* in argArgs.
+  masm.moveStackPtrTo(argArgs);
+
+  // Push |this| object for passing HandleObject. We push after argc to
+  // maintain the same sp-relative location of the object pointer with other
+  // DOMExitFrames.
+  masm.Push(argObj);
+  masm.moveStackPtrTo(argObj);
+
+  if (call->mir()->maybeCrossRealm()) {
+    // We use argJSContext as scratch register here.
+    masm.movePtr(ImmGCPtr(target->rawNativeJSFunction()), argJSContext);
+    masm.switchToObjectRealm(argJSContext, argJSContext);
+  }
+
+  // Construct native exit frame.
+  uint32_t safepointOffset = masm.buildFakeExitFrame(argJSContext);
+  masm.loadJSContext(argJSContext);
+  masm.enterFakeExitFrame(argJSContext, argJSContext,
+                          ExitFrameType::IonDOMMethod);
+
+  markSafepointAt(safepointOffset, call);
+
+  // Construct and execute call.
+  masm.setupUnalignedABICall(argJSContext);
+  masm.loadJSContext(argJSContext);
+  masm.passABIArg(argJSContext);
+  masm.passABIArg(argObj);
+  masm.passABIArg(argPrivate);
+  masm.passABIArg(argArgs);
+  masm.callWithABI(DynamicFunction<JSJitMethodOp>(target->jitInfo()->method),
+                   MoveOp::GENERAL,
+                   CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+  if (target->jitInfo()->isInfallible) {
+    masm.loadValue(Address(masm.getStackPointer(),
+                           IonDOMMethodExitFrameLayout::offsetOfResult()),
+                   JSReturnOperand);
+  } else {
+    // Test for failure.
+    masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+    // Load the outparam vp[0] into output register(s).
+    masm.loadValue(Address(masm.getStackPointer(),
+                           IonDOMMethodExitFrameLayout::offsetOfResult()),
+                   JSReturnOperand);
+  }
+
+  // Switch back to the current realm if needed. Note: if the DOM method threw
+  // an exception, the exception handler will do this.
+  if (call->mir()->maybeCrossRealm()) {
+    static_assert(!JSReturnOperand.aliases(ReturnReg),
+                  "Clobbering ReturnReg should not affect the return value");
+    masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+  }
+
+  // Until C++ code is instrumented against Spectre, prevent speculative
+  // execution from returning any private data.
+  if (JitOptions.spectreJitToCxxCalls && call->mir()->hasLiveDefUses()) {
+    masm.speculationBarrier();
+  }
+
+  // The next instruction is removing the footer of the exit frame, so there
+  // is no need for leaveFakeExitFrame.
+
+  // Move the StackPointer back to its original location, unwinding the native
+  // exit frame.
+  masm.adjustStack(IonDOMMethodExitFrameLayout::Size() - unusedStack);
+  MOZ_ASSERT(masm.framePushed() == initialStack);
+}
+
+void CodeGenerator::visitCallGetIntrinsicValue(LCallGetIntrinsicValue* lir) {
+  pushArg(ImmGCPtr(lir->mir()->name()));
+
+  using Fn = bool (*)(JSContext * cx, HandlePropertyName, MutableHandleValue);
+  callVM<Fn, GetIntrinsicValue>(lir);
+}
+
+void CodeGenerator::emitCallInvokeFunction(
+    LInstruction* call, Register calleereg, bool constructing,
+    bool ignoresReturnValue, uint32_t argc, uint32_t unusedStack) {
+  // Nestle %esp up to the argument vector.
+  // Each path must account for framePushed_ separately, for callVM to be valid.
+  masm.freeStack(unusedStack);
+
+  pushArg(masm.getStackPointer());  // argv.
+  pushArg(Imm32(argc));             // argc.
+  pushArg(Imm32(ignoresReturnValue));
+  pushArg(Imm32(constructing));  // constructing.
+  pushArg(calleereg);            // JSFunction*.
+
+  using Fn = bool (*)(JSContext*, HandleObject, bool, bool, uint32_t, Value*,
+                      MutableHandleValue);
+  callVM<Fn, jit::InvokeFunction>(call);
+
+  // Un-nestle %esp from the argument vector. No prefix was pushed.
+  masm.reserveStack(unusedStack);
+}
+
+void CodeGenerator::visitCallGeneric(LCallGeneric* call) {
+  Register calleereg = ToRegister(call->getFunction());
+  Register objreg = ToRegister(call->getTempObject());
+  Register nargsreg = ToRegister(call->getNargsReg());
+  uint32_t unusedStack = StackOffsetOfPassedArg(call->argslot());
+  Label invoke, thunk, makeCall, end;
+
+  // Known-target case is handled by LCallKnown.
+  MOZ_ASSERT(!call->hasSingleTarget());
+
+  masm.checkStackAlignment();
+
+  // Guard that calleereg is actually a function object.
+  if (call->mir()->needsClassCheck()) {
+    masm.branchTestObjClass(Assembler::NotEqual, calleereg, &JSFunction::class_,
+                            nargsreg, calleereg, &invoke);
+  }
+
+  // Guard that callee allows the [[Call]] or [[Construct]] operation required.
+  if (call->mir()->isConstructing()) {
+    masm.branchTestFunctionFlags(calleereg, FunctionFlags::CONSTRUCTOR,
+                                 Assembler::Zero, &invoke);
+  } else {
+    masm.branchFunctionKind(Assembler::Equal, FunctionFlags::ClassConstructor,
+                            calleereg, objreg, &invoke);
+  }
+
+  // Use the slow path if CreateThis was unable to create the |this| object.
+  if (call->mir()->needsThisCheck()) {
+    MOZ_ASSERT(call->mir()->isConstructing());
+    Address thisAddr(masm.getStackPointer(), unusedStack);
+    masm.branchTestNull(Assembler::Equal, thisAddr, &invoke);
+  } else {
+#ifdef DEBUG
+    if (call->mir()->isConstructing()) {
+      Address thisAddr(masm.getStackPointer(), unusedStack);
+      Label ok;
+      masm.branchTestNull(Assembler::NotEqual, thisAddr, &ok);
+      masm.assumeUnreachable("Unexpected null this-value");
+      masm.bind(&ok);
+    }
+#endif
+  }
+
+  // Load jitCodeRaw for callee if it exists.
+  masm.branchIfFunctionHasNoJitEntry(calleereg, call->mir()->isConstructing(),
+                                     &invoke);
+  masm.loadJitCodeRaw(calleereg, objreg);
+
+  // Target may be a different realm even if same compartment.
+  if (call->mir()->maybeCrossRealm()) {
+    masm.switchToObjectRealm(calleereg, nargsreg);
+  }
+
+  // Nestle the StackPointer up to the argument vector.
+  masm.freeStack(unusedStack);
+
+  // Construct the IonFramePrefix.
+  uint32_t descriptor = MakeFrameDescriptor(
+      masm.framePushed(), FrameType::IonJS, JitFrameLayout::Size());
+  masm.Push(Imm32(call->numActualArgs()));
+  masm.PushCalleeToken(calleereg, call->mir()->isConstructing());
+  masm.Push(Imm32(descriptor));
+
+  // Check whether the provided arguments satisfy target argc.
+  // We cannot have lowered to LCallGeneric with a known target. Assert that we
+  // didn't add any undefineds in WarpBuilder. NB: MCall::numStackArgs includes
+  // |this|.
+  DebugOnly<unsigned> numNonArgsOnStack = 1 + call->isConstructing();
+  MOZ_ASSERT(call->numActualArgs() ==
+             call->mir()->numStackArgs() - numNonArgsOnStack);
+  masm.load16ZeroExtend(Address(calleereg, JSFunction::offsetOfNargs()),
+                        nargsreg);
+  masm.branch32(Assembler::Above, nargsreg, Imm32(call->numActualArgs()),
+                &thunk);
+  masm.jump(&makeCall);
+
+  // Argument fixup needed. Load the ArgumentsRectifier.
+  masm.bind(&thunk);
+  {
+    TrampolinePtr argumentsRectifier =
+        gen->jitRuntime()->getArgumentsRectifier();
+    masm.movePtr(argumentsRectifier, objreg);
+  }
+
+  // Finally call the function in objreg.
+  masm.bind(&makeCall);
+  uint32_t callOffset = masm.callJit(objreg);
+  markSafepointAt(callOffset, call);
+
+  if (call->mir()->maybeCrossRealm()) {
+    static_assert(!JSReturnOperand.aliases(ReturnReg),
+                  "ReturnReg available as scratch after scripted calls");
+    masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+  }
+
+  // Increment to remove IonFramePrefix; decrement to fill FrameSizeClass.
+  // The return address has already been removed from the Ion frame.
+  int prefixGarbage = sizeof(JitFrameLayout) - sizeof(void*);
+  masm.adjustStack(prefixGarbage - unusedStack);
+  masm.jump(&end);
+
+  // Handle uncompiled or native functions.
+  masm.bind(&invoke);
+  emitCallInvokeFunction(call, calleereg, call->isConstructing(),
+                         call->ignoresReturnValue(), call->numActualArgs(),
+                         unusedStack);
+
+  masm.bind(&end);
+
+  // If the return value of the constructing function is Primitive,
+  // replace the return value with the Object from CreateThis.
+  if (call->mir()->isConstructing()) {
+    Label notPrimitive;
+    masm.branchTestPrimitive(Assembler::NotEqual, JSReturnOperand,
+                             &notPrimitive);
+    masm.loadValue(Address(masm.getStackPointer(), unusedStack),
+                   JSReturnOperand);
+    masm.bind(&notPrimitive);
+  }
+}
+
+void CodeGenerator::visitCallKnown(LCallKnown* call) {
+  Register calleereg = ToRegister(call->getFunction());
+  Register objreg = ToRegister(call->getTempObject());
+  uint32_t unusedStack = StackOffsetOfPassedArg(call->argslot());
+  WrappedFunction* target = call->getSingleTarget();
+
+  // Native single targets (except wasm) are handled by LCallNative.
+  MOZ_ASSERT(target->hasJitEntry());
+
+  // Missing arguments must have been explicitly appended by WarpBuilder.
+  DebugOnly<unsigned> numNonArgsOnStack = 1 + call->isConstructing();
+  MOZ_ASSERT(target->nargs() <=
+             call->mir()->numStackArgs() - numNonArgsOnStack);
+
+  MOZ_ASSERT_IF(call->isConstructing(), target->isConstructor());
+
+  masm.checkStackAlignment();
+
+  if (target->isClassConstructor() && !call->isConstructing()) {
+    emitCallInvokeFunction(call, calleereg, call->isConstructing(),
+                           call->ignoresReturnValue(), call->numActualArgs(),
+                           unusedStack);
+    return;
+  }
+
+  MOZ_ASSERT_IF(target->isClassConstructor(), call->isConstructing());
+
+  MOZ_ASSERT(!call->mir()->needsThisCheck());
+
+  if (call->mir()->maybeCrossRealm()) {
+    masm.switchToObjectRealm(calleereg, objreg);
+  }
+
+  masm.loadJitCodeRaw(calleereg, objreg);
+
+  // Nestle the StackPointer up to the argument vector.
+  masm.freeStack(unusedStack);
+
+  // Construct the IonFramePrefix.
+  uint32_t descriptor = MakeFrameDescriptor(
+      masm.framePushed(), FrameType::IonJS, JitFrameLayout::Size());
+  masm.Push(Imm32(call->numActualArgs()));
+  masm.PushCalleeToken(calleereg, call->mir()->isConstructing());
+  masm.Push(Imm32(descriptor));
+
+  // Finally call the function in objreg.
+  uint32_t callOffset = masm.callJit(objreg);
+  markSafepointAt(callOffset, call);
+
+  if (call->mir()->maybeCrossRealm()) {
+    static_assert(!JSReturnOperand.aliases(ReturnReg),
+                  "ReturnReg available as scratch after scripted calls");
+    masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+  }
+
+  // Increment to remove IonFramePrefix; decrement to fill FrameSizeClass.
+  // The return address has already been removed from the Ion frame.
+  int prefixGarbage = sizeof(JitFrameLayout) - sizeof(void*);
+  masm.adjustStack(prefixGarbage - unusedStack);
+
+  // If the return value of the constructing function is Primitive,
+  // replace the return value with the Object from CreateThis.
+  if (call->mir()->isConstructing()) {
+    Label notPrimitive;
+    masm.branchTestPrimitive(Assembler::NotEqual, JSReturnOperand,
+                             &notPrimitive);
+    masm.loadValue(Address(masm.getStackPointer(), unusedStack),
+                   JSReturnOperand);
+    masm.bind(&notPrimitive);
+  }
+}
+
+template <typename T>
+void CodeGenerator::emitCallInvokeFunction(T* apply, Register extraStackSize) {
+  Register objreg = ToRegister(apply->getTempObject());
+  MOZ_ASSERT(objreg != extraStackSize);
+
+  // Push the space used by the arguments.
+  masm.moveStackPtrTo(objreg);
+  masm.Push(extraStackSize);
+
+  pushArg(objreg);                                     // argv.
+  pushArg(ToRegister(apply->getArgc()));               // argc.
+  pushArg(Imm32(apply->mir()->ignoresReturnValue()));  // ignoresReturnValue.
+  pushArg(Imm32(apply->mir()->isConstructing()));      // isConstructing.
+  pushArg(ToRegister(apply->getFunction()));           // JSFunction*.
+
+  // This specialization of callVM restores the extraStackSize after the call.
+  using Fn = bool (*)(JSContext*, HandleObject, bool, bool, uint32_t, Value*,
+                      MutableHandleValue);
+  callVM<Fn, jit::InvokeFunction>(apply, &extraStackSize);
+
+  masm.Pop(extraStackSize);
+}
+
+// Do not bailout after the execution of this function since the stack no longer
+// correspond to what is expected by the snapshots.
+void CodeGenerator::emitAllocateSpaceForApply(Register argcreg,
+                                              Register extraStackSpace) {
+  // Initialize the loop counter AND Compute the stack usage (if == 0)
+  masm.movePtr(argcreg, extraStackSpace);
+
+  // Align the JitFrameLayout on the JitStackAlignment.
+  if (JitStackValueAlignment > 1) {
+    MOZ_ASSERT(frameSize() % JitStackAlignment == 0,
+               "Stack padding assumes that the frameSize is correct");
+    MOZ_ASSERT(JitStackValueAlignment == 2);
+    Label noPaddingNeeded;
+    // if the number of arguments is odd, then we do not need any padding.
+    masm.branchTestPtr(Assembler::NonZero, argcreg, Imm32(1), &noPaddingNeeded);
+    masm.addPtr(Imm32(1), extraStackSpace);
+    masm.bind(&noPaddingNeeded);
+  }
+
+  // Reserve space for copying the arguments.
+  NativeObject::elementsSizeMustNotOverflow();
+  masm.lshiftPtr(Imm32(ValueShift), extraStackSpace);
+  masm.subFromStackPtr(extraStackSpace);
+
+#ifdef DEBUG
+  // Put a magic value in the space reserved for padding. Note, this code
+  // cannot be merged with the previous test, as not all architectures can
+  // write below their stack pointers.
+  if (JitStackValueAlignment > 1) {
+    MOZ_ASSERT(JitStackValueAlignment == 2);
+    Label noPaddingNeeded;
+    // if the number of arguments is odd, then we do not need any padding.
+    masm.branchTestPtr(Assembler::NonZero, argcreg, Imm32(1), &noPaddingNeeded);
+    BaseValueIndex dstPtr(masm.getStackPointer(), argcreg);
+    masm.storeValue(MagicValue(JS_ARG_POISON), dstPtr);
+    masm.bind(&noPaddingNeeded);
+  }
+#endif
+}
+
+// Do not bailout after the execution of this function since the stack no longer
+// correspond to what is expected by the snapshots.
+void CodeGenerator::emitAllocateSpaceForConstructAndPushNewTarget(
+    Register argcreg, Register newTargetAndExtraStackSpace) {
+  // Align the JitFrameLayout on the JitStackAlignment. Contrary to
+  // |emitAllocateSpaceForApply()|, we're always pushing a magic value, because
+  // we can't write to |newTargetAndExtraStackSpace| before |new.target| has
+  // been pushed onto the stack.
+  if (JitStackValueAlignment > 1) {
+    MOZ_ASSERT(frameSize() % JitStackAlignment == 0,
+               "Stack padding assumes that the frameSize is correct");
+    MOZ_ASSERT(JitStackValueAlignment == 2);
+
+    Label noPaddingNeeded;
+    // If the number of arguments is even, then we do not need any padding.
+    masm.branchTestPtr(Assembler::Zero, argcreg, Imm32(1), &noPaddingNeeded);
+    masm.pushValue(MagicValue(JS_ARG_POISON));
+    masm.bind(&noPaddingNeeded);
+  }
+
+  // Push |new.target| after the padding value, but before any arguments.
+  masm.pushValue(JSVAL_TYPE_OBJECT, newTargetAndExtraStackSpace);
+
+  // Initialize the loop counter AND compute the stack usage.
+  masm.movePtr(argcreg, newTargetAndExtraStackSpace);
+
+  // Reserve space for copying the arguments.
+  NativeObject::elementsSizeMustNotOverflow();
+  masm.lshiftPtr(Imm32(ValueShift), newTargetAndExtraStackSpace);
+  masm.subFromStackPtr(newTargetAndExtraStackSpace);
+
+  // Account for |new.target| which has already been pushed onto the stack.
+  masm.addPtr(Imm32(sizeof(Value)), newTargetAndExtraStackSpace);
+
+  // And account for the padding.
+  if (JitStackValueAlignment > 1) {
+    MOZ_ASSERT(frameSize() % JitStackAlignment == 0,
+               "Stack padding assumes that the frameSize is correct");
+    MOZ_ASSERT(JitStackValueAlignment == 2);
+
+    Label noPaddingNeeded;
+    // If the number of arguments is even, then we do not need any padding.
+    masm.branchTestPtr(Assembler::Zero, argcreg, Imm32(1), &noPaddingNeeded);
+    masm.addPtr(Imm32(sizeof(Value)), newTargetAndExtraStackSpace);
+    masm.bind(&noPaddingNeeded);
+  }
+}
+
+// Destroys argvIndex and copyreg.
+void CodeGenerator::emitCopyValuesForApply(Register argvSrcBase,
+                                           Register argvIndex, Register copyreg,
+                                           size_t argvSrcOffset,
+                                           size_t argvDstOffset) {
+  Label loop;
+  masm.bind(&loop);
+
+  // As argvIndex is off by 1, and we use the decBranchPtr instruction
+  // to loop back, we have to substract the size of the word which are
+  // copied.
+  BaseValueIndex srcPtr(argvSrcBase, argvIndex, argvSrcOffset - sizeof(void*));
+  BaseValueIndex dstPtr(masm.getStackPointer(), argvIndex,
+                        argvDstOffset - sizeof(void*));
+  masm.loadPtr(srcPtr, copyreg);
+  masm.storePtr(copyreg, dstPtr);
+
+  // Handle 32 bits architectures.
+  if (sizeof(Value) == 2 * sizeof(void*)) {
+    BaseValueIndex srcPtrLow(argvSrcBase, argvIndex,
+                             argvSrcOffset - 2 * sizeof(void*));
+    BaseValueIndex dstPtrLow(masm.getStackPointer(), argvIndex,
+                             argvDstOffset - 2 * sizeof(void*));
+    masm.loadPtr(srcPtrLow, copyreg);
+    masm.storePtr(copyreg, dstPtrLow);
+  }
+
+  masm.decBranchPtr(Assembler::NonZero, argvIndex, Imm32(1), &loop);
+}
+
+void CodeGenerator::emitPopArguments(Register extraStackSpace) {
+  // Pop |this| and Arguments.
+  masm.freeStack(extraStackSpace);
+}
+
+void CodeGenerator::emitPushArguments(LApplyArgsGeneric* apply,
+                                      Register extraStackSpace) {
+  // Holds the function nargs. Initially the number of args to the caller.
+  Register argcreg = ToRegister(apply->getArgc());
+  Register copyreg = ToRegister(apply->getTempObject());
+
+  Label end;
+  emitAllocateSpaceForApply(argcreg, extraStackSpace);
+
+  // Skip the copy of arguments if there are none.
+  masm.branchTestPtr(Assembler::Zero, argcreg, argcreg, &end);
+
+  // clang-format off
+  //
+  // We are making a copy of the arguments which are above the JitFrameLayout
+  // of the current Ion frame.
+  //
+  // [arg1] [arg0] <- src [this] [JitFrameLayout] [.. frameSize ..] [pad] [arg1] [arg0] <- dst
+  //
+  // clang-format on
+
+  // Compute the source and destination offsets into the stack.
+  size_t argvSrcOffset = frameSize() + JitFrameLayout::offsetOfActualArgs();
+  size_t argvDstOffset = 0;
+
+  // Save the extra stack space, and re-use the register as a base.
+  masm.push(extraStackSpace);
+  Register argvSrcBase = extraStackSpace;
+  argvSrcOffset += sizeof(void*);
+  argvDstOffset += sizeof(void*);
+
+  // Save the actual number of register, and re-use the register as an index
+  // register.
+  masm.push(argcreg);
+  Register argvIndex = argcreg;
+  argvSrcOffset += sizeof(void*);
+  argvDstOffset += sizeof(void*);
+
+  // srcPtr = (StackPointer + extraStackSpace) + argvSrcOffset
+  // dstPtr = (StackPointer                  ) + argvDstOffset
+  masm.addStackPtrTo(argvSrcBase);
+
+  // Copy arguments.
+  emitCopyValuesForApply(argvSrcBase, argvIndex, copyreg, argvSrcOffset,
+                         argvDstOffset);
+
+  // Restore argcreg and the extra stack space counter.
+  masm.pop(argcreg);
+  masm.pop(extraStackSpace);
+
+  // Join with all arguments copied and the extra stack usage computed.
+  masm.bind(&end);
+
+  // Push |this|.
+  masm.addPtr(Imm32(sizeof(Value)), extraStackSpace);
+  masm.pushValue(ToValue(apply, LApplyArgsGeneric::ThisIndex));
+}
+
+void CodeGenerator::emitPushElementsAsArguments(Register tmpArgc,
+                                                Register elementsAndArgc,
+                                                Register extraStackSpace) {
+  // Pushes |tmpArgc| number of elements stored in |elementsAndArgc| onto the
+  // stack. |extraStackSpace| is used as a temp register within this function,
+  // but must be restored before returning.
+  // On exit, |tmpArgc| is written to |elementsAndArgc|, so we can keep using
+  // |tmpArgc| as a scratch register. And |elementsAndArgc| is from now on the
+  // register holding the arguments count.
+
+  Label noCopy, epilogue;
+
+  // Skip the copy of arguments if there are none.
+  masm.branchTestPtr(Assembler::Zero, tmpArgc, tmpArgc, &noCopy);
+
+  // Copy the values.  This code is skipped entirely if there are
+  // no values.
+  size_t argvDstOffset = 0;
+
+  Register argvSrcBase = elementsAndArgc;  // Elements value
+
+  masm.push(extraStackSpace);
+  Register copyreg = extraStackSpace;
+  argvDstOffset += sizeof(void*);
+
+  masm.push(tmpArgc);
+  Register argvIndex = tmpArgc;
+  argvDstOffset += sizeof(void*);
+
+  // Copy
+  emitCopyValuesForApply(argvSrcBase, argvIndex, copyreg, 0, argvDstOffset);
+
+  // Restore.
+  masm.pop(elementsAndArgc);
+  masm.pop(extraStackSpace);
+  masm.jump(&epilogue);
+
+  // Clear argc if we skipped the copy step.
+  masm.bind(&noCopy);
+  masm.movePtr(ImmPtr(0), elementsAndArgc);
+
+  // Join with all arguments copied and the extra stack usage computed.
+  // Note, "elements" has become "argc".
+  masm.bind(&epilogue);
+}
+
+void CodeGenerator::emitPushArguments(LApplyArrayGeneric* apply,
+                                      Register extraStackSpace) {
+  Register tmpArgc = ToRegister(apply->getTempObject());
+  Register elementsAndArgc = ToRegister(apply->getElements());
+
+  // Invariants guarded in the caller:
+  //  - the array is not too long
+  //  - the array length equals its initialized length
+
+  // The array length is our argc for the purposes of allocating space.
+  Address length(ToRegister(apply->getElements()),
+                 ObjectElements::offsetOfLength());
+  masm.load32(length, tmpArgc);
+
+  // Allocate space for the values.
+  emitAllocateSpaceForApply(tmpArgc, extraStackSpace);
+
+  // After this call "elements" has become "argc".
+  emitPushElementsAsArguments(tmpArgc, elementsAndArgc, extraStackSpace);
+
+  // Push |this|.
+  masm.addPtr(Imm32(sizeof(Value)), extraStackSpace);
+  masm.pushValue(ToValue(apply, LApplyArrayGeneric::ThisIndex));
+}
+
+void CodeGenerator::emitPushArguments(LConstructArrayGeneric* construct,
+                                      Register extraStackSpace) {
+  MOZ_ASSERT(extraStackSpace == ToRegister(construct->getNewTarget()));
+
+  Register tmpArgc = ToRegister(construct->getTempObject());
+  Register elementsAndArgc = ToRegister(construct->getElements());
+
+  // Invariants guarded in the caller:
+  //  - the array is not too long
+  //  - the array length equals its initialized length
+
+  // The array length is our argc for the purposes of allocating space.
+  Address length(ToRegister(construct->getElements()),
+                 ObjectElements::offsetOfLength());
+  masm.load32(length, tmpArgc);
+
+  // Allocate space for the values.
+  emitAllocateSpaceForConstructAndPushNewTarget(tmpArgc, extraStackSpace);
+
+  // After this call "elements" has become "argc" and "newTarget" has become
+  // "extraStackSpace".
+  emitPushElementsAsArguments(tmpArgc, elementsAndArgc, extraStackSpace);
+
+  // Push |this|.
+  masm.addPtr(Imm32(sizeof(Value)), extraStackSpace);
+  masm.pushValue(ToValue(construct, LConstructArrayGeneric::ThisIndex));
+}
+
+template <typename T>
+void CodeGenerator::emitApplyGeneric(T* apply) {
+  // Holds the function object.
+  Register calleereg = ToRegister(apply->getFunction());
+
+  // Temporary register for modifying the function object.
+  Register objreg = ToRegister(apply->getTempObject());
+  Register extraStackSpace = ToRegister(apply->getTempStackCounter());
+
+  // Holds the function nargs, computed in the invoker or (for ApplyArray and
+  // ConstructArray) in the argument pusher.
+  Register argcreg = ToRegister(apply->getArgc());
+
+  // Copy the arguments of the current function.
+  //
+  // In the case of ApplyArray and ConstructArray, also compute argc: the argc
+  // register and the elements register are the same; argc must not be
+  // referenced before the call to emitPushArguments() and elements must not be
+  // referenced after it returns.
+  //
+  // In the case of ConstructArray, also overwrite newTarget with
+  // extraStackSpace; newTarget must not be referenced after this point.
+  //
+  // objreg is dead across this call.
+  //
+  // extraStackSpace is garbage on entry (for ApplyArray and ApplyArgs) and
+  // defined on exit.
+  emitPushArguments(apply, extraStackSpace);
+
+  masm.checkStackAlignment();
+
+  bool constructing = apply->mir()->isConstructing();
+
+  // If the function is native, only emit the call to InvokeFunction.
+  if (apply->hasSingleTarget() &&
+      apply->getSingleTarget()->isNativeWithoutJitEntry()) {
+    emitCallInvokeFunction(apply, extraStackSpace);
+
+#ifdef DEBUG
+    // Native constructors are guaranteed to return an Object value, so we never
+    // have to replace a primitive result with the previously allocated Object
+    // from CreateThis.
+    if (constructing) {
+      Label notPrimitive;
+      masm.branchTestPrimitive(Assembler::NotEqual, JSReturnOperand,
+                               &notPrimitive);
+      masm.assumeUnreachable("native constructors don't return primitives");
+      masm.bind(&notPrimitive);
+    }
+#endif
+
+    emitPopArguments(extraStackSpace);
+    return;
+  }
+
+  Label end, invoke;
+
+  // Unless already known, guard that calleereg is actually a function object.
+  if (!apply->hasSingleTarget()) {
+    masm.branchTestObjClass(Assembler::NotEqual, calleereg, &JSFunction::class_,
+                            objreg, calleereg, &invoke);
+  }
+
+  // Guard that calleereg is an interpreted function with a JSScript.
+  masm.branchIfFunctionHasNoJitEntry(calleereg, constructing, &invoke);
+
+  // Guard that callee allows the [[Call]] or [[Construct]] operation required.
+  if (constructing) {
+    masm.branchTestFunctionFlags(calleereg, FunctionFlags::CONSTRUCTOR,
+                                 Assembler::Zero, &invoke);
+  } else {
+    masm.branchFunctionKind(Assembler::Equal, FunctionFlags::ClassConstructor,
+                            calleereg, objreg, &invoke);
+  }
+
+  // Use the slow path if CreateThis was unable to create the |this| object.
+  if (constructing) {
+    Address thisAddr(masm.getStackPointer(), 0);
+    masm.branchTestNull(Assembler::Equal, thisAddr, &invoke);
+  }
+
+  // Call with an Ion frame or a rectifier frame.
+  {
+    if (apply->mir()->maybeCrossRealm()) {
+      masm.switchToObjectRealm(calleereg, objreg);
+    }
+
+    // Knowing that calleereg is a non-native function, load jitcode.
+    masm.loadJitCodeRaw(calleereg, objreg);
+
+    // Create the frame descriptor.
+    unsigned pushed = masm.framePushed();
+    Register stackSpace = extraStackSpace;
+    masm.addPtr(Imm32(pushed), stackSpace);
+    masm.makeFrameDescriptor(stackSpace, FrameType::IonJS,
+                             JitFrameLayout::Size());
+
+    masm.Push(argcreg);
+    masm.PushCalleeToken(calleereg, constructing);
+    masm.Push(stackSpace);  // descriptor
+
+    Label underflow, rejoin;
+
+    // Check whether the provided arguments satisfy target argc.
+    if (!apply->hasSingleTarget()) {
+      Register nformals = extraStackSpace;
+      masm.load16ZeroExtend(Address(calleereg, JSFunction::offsetOfNargs()),
+                            nformals);
+      masm.branch32(Assembler::Below, argcreg, nformals, &underflow);
+    } else {
+      masm.branch32(Assembler::Below, argcreg,
+                    Imm32(apply->getSingleTarget()->nargs()), &underflow);
+    }
+
+    // Skip the construction of the rectifier frame because we have no
+    // underflow.
+    masm.jump(&rejoin);
+
+    // Argument fixup needed. Get ready to call the argumentsRectifier.
+    {
+      masm.bind(&underflow);
+
+      // Hardcode the address of the argumentsRectifier code.
+      TrampolinePtr argumentsRectifier =
+          gen->jitRuntime()->getArgumentsRectifier();
+      masm.movePtr(argumentsRectifier, objreg);
+    }
+
+    masm.bind(&rejoin);
+
+    // Finally call the function in objreg, as assigned by one of the paths
+    // above.
+    uint32_t callOffset = masm.callJit(objreg);
+    markSafepointAt(callOffset, apply);
+
+    if (apply->mir()->maybeCrossRealm()) {
+      static_assert(!JSReturnOperand.aliases(ReturnReg),
+                    "ReturnReg available as scratch after scripted calls");
+      masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+    }
+
+    // Recover the number of arguments from the frame descriptor.
+    masm.loadPtr(Address(masm.getStackPointer(), 0), stackSpace);
+    masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), stackSpace);
+    masm.subPtr(Imm32(pushed), stackSpace);
+
+    // Increment to remove IonFramePrefix; decrement to fill FrameSizeClass.
+    // The return address has already been removed from the Ion frame.
+    int prefixGarbage = sizeof(JitFrameLayout) - sizeof(void*);
+    masm.adjustStack(prefixGarbage);
+    masm.jump(&end);
+  }
+
+  // Handle uncompiled or native functions.
+  {
+    masm.bind(&invoke);
+    emitCallInvokeFunction(apply, extraStackSpace);
+  }
+
+  masm.bind(&end);
+
+  // If the return value of the constructing function is Primitive,
+  // replace the return value with the Object from CreateThis.
+  if (constructing) {
+    Label notPrimitive;
+    masm.branchTestPrimitive(Assembler::NotEqual, JSReturnOperand,
+                             &notPrimitive);
+    masm.loadValue(Address(masm.getStackPointer(), 0), JSReturnOperand);
+    masm.bind(&notPrimitive);
+  }
+
+  // Pop arguments and continue.
+  emitPopArguments(extraStackSpace);
+}
+
+void CodeGenerator::visitApplyArgsGeneric(LApplyArgsGeneric* apply) {
+  LSnapshot* snapshot = apply->snapshot();
+  Register argcreg = ToRegister(apply->getArgc());
+
+  // Ensure that we have a reasonable number of arguments.
+  bailoutCmp32(Assembler::Above, argcreg, Imm32(JIT_ARGS_LENGTH_MAX), snapshot);
+
+  emitApplyGeneric(apply);
+}
+
+void CodeGenerator::visitApplyArrayGeneric(LApplyArrayGeneric* apply) {
+  LSnapshot* snapshot = apply->snapshot();
+  Register tmp = ToRegister(apply->getTempObject());
+
+  Address length(ToRegister(apply->getElements()),
+                 ObjectElements::offsetOfLength());
+  masm.load32(length, tmp);
+
+  // Ensure that we have a reasonable number of arguments.
+  bailoutCmp32(Assembler::Above, tmp, Imm32(JIT_ARGS_LENGTH_MAX), snapshot);
+
+  // Ensure that the array does not contain an uninitialized tail.
+
+  Address initializedLength(ToRegister(apply->getElements()),
+                            ObjectElements::offsetOfInitializedLength());
+  masm.sub32(initializedLength, tmp);
+  bailoutCmp32(Assembler::NotEqual, tmp, Imm32(0), snapshot);
+
+  emitApplyGeneric(apply);
+}
+
+void CodeGenerator::visitConstructArrayGeneric(LConstructArrayGeneric* lir) {
+  LSnapshot* snapshot = lir->snapshot();
+  Register tmp = ToRegister(lir->getTempObject());
+
+  Address length(ToRegister(lir->getElements()),
+                 ObjectElements::offsetOfLength());
+  masm.load32(length, tmp);
+
+  // Ensure that we have a reasonable number of arguments.
+  bailoutCmp32(Assembler::Above, tmp, Imm32(JIT_ARGS_LENGTH_MAX), snapshot);
+
+  // Ensure that the array does not contain an uninitialized tail.
+
+  Address initializedLength(ToRegister(lir->getElements()),
+                            ObjectElements::offsetOfInitializedLength());
+  masm.sub32(initializedLength, tmp);
+  bailoutCmp32(Assembler::NotEqual, tmp, Imm32(0), snapshot);
+
+  emitApplyGeneric(lir);
+}
+
+void CodeGenerator::visitBail(LBail* lir) { bailout(lir->snapshot()); }
+
+void CodeGenerator::visitUnreachable(LUnreachable* lir) {
+  masm.assumeUnreachable("end-of-block assumed unreachable");
+}
+
+void CodeGenerator::visitEncodeSnapshot(LEncodeSnapshot* lir) {
+  encode(lir->snapshot());
+}
+
+void CodeGenerator::visitUnreachableResultV(LUnreachableResultV* lir) {
+  masm.assumeUnreachable("must be unreachable");
+}
+
+void CodeGenerator::visitUnreachableResultT(LUnreachableResultT* lir) {
+  masm.assumeUnreachable("must be unreachable");
+}
+
+// Out-of-line path to report over-recursed error and fail.
+class CheckOverRecursedFailure : public OutOfLineCodeBase<CodeGenerator> {
+  LInstruction* lir_;
+
+ public:
+  explicit CheckOverRecursedFailure(LInstruction* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitCheckOverRecursedFailure(this);
+  }
+
+  LInstruction* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitCheckOverRecursed(LCheckOverRecursed* lir) {
+  // If we don't push anything on the stack, skip the check.
+  if (omitOverRecursedCheck()) {
+    return;
+  }
+
+  // Ensure that this frame will not cross the stack limit.
+  // This is a weak check, justified by Ion using the C stack: we must always
+  // be some distance away from the actual limit, since if the limit is
+  // crossed, an error must be thrown, which requires more frames.
+  //
+  // It must always be possible to trespass past the stack limit.
+  // Ion may legally place frames very close to the limit. Calling additional
+  // C functions may then violate the limit without any checking.
+  //
+  // Since Ion frames exist on the C stack, the stack limit may be
+  // dynamically set by JS_SetThreadStackLimit() and JS_SetNativeStackQuota().
+
+  CheckOverRecursedFailure* ool = new (alloc()) CheckOverRecursedFailure(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  // Conditional forward (unlikely) branch to failure.
+  const void* limitAddr = gen->runtime->addressOfJitStackLimit();
+  masm.branchStackPtrRhs(Assembler::AboveOrEqual, AbsoluteAddress(limitAddr),
+                         ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCheckOverRecursedFailure(
+    CheckOverRecursedFailure* ool) {
+  // The OOL path is hit if the recursion depth has been exceeded.
+  // Throw an InternalError for over-recursion.
+
+  // LFunctionEnvironment can appear before LCheckOverRecursed, so we have
+  // to save all live registers to avoid crashes if CheckOverRecursed triggers
+  // a GC.
+  saveLive(ool->lir());
+
+  using Fn = bool (*)(JSContext*);
+  callVM<Fn, CheckOverRecursed>(ool->lir());
+
+  restoreLive(ool->lir());
+  masm.jump(ool->rejoin());
+}
+
+IonScriptCounts* CodeGenerator::maybeCreateScriptCounts() {
+  // If scripts are being profiled, create a new IonScriptCounts for the
+  // profiling data, which will be attached to the associated JSScript or
+  // wasm module after code generation finishes.
+  if (!gen->hasProfilingScripts()) {
+    return nullptr;
+  }
+
+  // This test inhibits IonScriptCount creation for wasm code which is
+  // currently incompatible with wasm codegen for two reasons: (1) wasm code
+  // must be serializable and script count codegen bakes in absolute
+  // addresses, (2) wasm code does not have a JSScript with which to associate
+  // code coverage data.
+  JSScript* script = gen->outerInfo().script();
+  if (!script) {
+    return nullptr;
+  }
+
+  auto counts = MakeUnique<IonScriptCounts>();
+  if (!counts || !counts->init(graph.numBlocks())) {
+    return nullptr;
+  }
+
+  for (size_t i = 0; i < graph.numBlocks(); i++) {
+    MBasicBlock* block = graph.getBlock(i)->mir();
+
+    uint32_t offset = 0;
+    char* description = nullptr;
+    if (MResumePoint* resume = block->entryResumePoint()) {
+      // Find a PC offset in the outermost script to use. If this
+      // block is from an inlined script, find a location in the
+      // outer script to associate information about the inlining
+      // with.
+      while (resume->caller()) {
+        resume = resume->caller();
+      }
+      offset = script->pcToOffset(resume->pc());
+
+      if (block->entryResumePoint()->caller()) {
+        // Get the filename and line number of the inner script.
+        JSScript* innerScript = block->info().script();
+        description = js_pod_calloc<char>(200);
+        if (description) {
+          snprintf(description, 200, "%s:%u", innerScript->filename(),
+                   innerScript->lineno());
+        }
+      }
+    }
+
+    if (!counts->block(i).init(block->id(), offset, description,
+                               block->numSuccessors())) {
+      return nullptr;
+    }
+
+    for (size_t j = 0; j < block->numSuccessors(); j++) {
+      counts->block(i).setSuccessor(
+          j, skipTrivialBlocks(block->getSuccessor(j))->id());
+    }
+  }
+
+  scriptCounts_ = counts.release();
+  return scriptCounts_;
+}
+
+// Structure for managing the state tracked for a block by script counters.
+struct ScriptCountBlockState {
+  IonBlockCounts& block;
+  MacroAssembler& masm;
+
+  Sprinter printer;
+
+ public:
+  ScriptCountBlockState(IonBlockCounts* block, MacroAssembler* masm)
+      : block(*block), masm(*masm), printer(GetJitContext()->cx, false) {}
+
+  bool init() {
+    if (!printer.init()) {
+      return false;
+    }
+
+    // Bump the hit count for the block at the start. This code is not
+    // included in either the text for the block or the instruction byte
+    // counts.
+    masm.inc64(AbsoluteAddress(block.addressOfHitCount()));
+
+    // Collect human readable assembly for the code generated in the block.
+    masm.setPrinter(&printer);
+
+    return true;
+  }
+
+  void visitInstruction(LInstruction* ins) {
+#ifdef JS_JITSPEW
+    // Prefix stream of assembly instructions with their LIR instruction
+    // name and any associated high level info.
+    if (const char* extra = ins->getExtraName()) {
+      printer.printf("[%s:%s]\n", ins->opName(), extra);
+    } else {
+      printer.printf("[%s]\n", ins->opName());
+    }
+#endif
+  }
+
+  ~ScriptCountBlockState() {
+    masm.setPrinter(nullptr);
+
+    if (!printer.hadOutOfMemory()) {
+      block.setCode(printer.string());
+    }
+  }
+};
+
+void CodeGenerator::branchIfInvalidated(Register temp, Label* invalidated) {
+  CodeOffset label = masm.movWithPatch(ImmWord(uintptr_t(-1)), temp);
+  masm.propagateOOM(ionScriptLabels_.append(label));
+
+  // If IonScript::invalidationCount_ != 0, the script has been invalidated.
+  masm.branch32(Assembler::NotEqual,
+                Address(temp, IonScript::offsetOfInvalidationCount()), Imm32(0),
+                invalidated);
+}
+
+#ifdef DEBUG
+void CodeGenerator::emitAssertGCThingResult(Register input,
+                                            const MDefinition* mir) {
+  MIRType type = mir->type();
+  MOZ_ASSERT(type == MIRType::Object || type == MIRType::String ||
+             type == MIRType::Symbol || type == MIRType::BigInt);
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(input);
+
+  Register temp = regs.takeAny();
+  masm.push(temp);
+
+  // Don't check if the script has been invalidated. In that case invalid
+  // types are expected (until we reach the OsiPoint and bailout).
+  Label done;
+  branchIfInvalidated(temp, &done);
+
+#  ifndef JS_SIMULATOR
+  // Check that we have a valid GC pointer.
+  // Disable for wasm because we don't have a context on wasm compilation
+  // threads and this needs a context.
+  // Also disable for simulator builds because the C++ call is a lot slower
+  // there than on actual hardware.
+  if (JitOptions.fullDebugChecks && !IsCompilingWasm()) {
+    saveVolatile();
+    masm.setupUnalignedABICall(temp);
+    masm.loadJSContext(temp);
+    masm.passABIArg(temp);
+    masm.passABIArg(input);
+
+    switch (type) {
+      case MIRType::Object: {
+        using Fn = void (*)(JSContext * cx, JSObject * obj);
+        masm.callWithABI<Fn, AssertValidObjectPtr>();
+        break;
+      }
+      case MIRType::String: {
+        using Fn = void (*)(JSContext * cx, JSString * str);
+        masm.callWithABI<Fn, AssertValidStringPtr>();
+        break;
+      }
+      case MIRType::Symbol: {
+        using Fn = void (*)(JSContext * cx, JS::Symbol * sym);
+        masm.callWithABI<Fn, AssertValidSymbolPtr>();
+        break;
+      }
+      case MIRType::BigInt: {
+        using Fn = void (*)(JSContext * cx, JS::BigInt * bi);
+        masm.callWithABI<Fn, AssertValidBigIntPtr>();
+        break;
+      }
+      default:
+        MOZ_CRASH();
+    }
+
+    restoreVolatile();
+  }
+#  endif
+
+  masm.bind(&done);
+  masm.pop(temp);
+}
+
+void CodeGenerator::emitAssertResultV(const ValueOperand input,
+                                      const MDefinition* mir) {
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+  regs.take(input);
+
+  Register temp1 = regs.takeAny();
+  Register temp2 = regs.takeAny();
+  masm.push(temp1);
+  masm.push(temp2);
+
+  // Don't check if the script has been invalidated. In that case invalid
+  // types are expected (until we reach the OsiPoint and bailout).
+  Label done;
+  branchIfInvalidated(temp1, &done);
+
+  // Check that we have a valid GC pointer.
+  if (JitOptions.fullDebugChecks) {
+    saveVolatile();
+
+    masm.pushValue(input);
+    masm.moveStackPtrTo(temp1);
+
+    using Fn = void (*)(JSContext * cx, Value * v);
+    masm.setupUnalignedABICall(temp2);
+    masm.loadJSContext(temp2);
+    masm.passABIArg(temp2);
+    masm.passABIArg(temp1);
+    masm.callWithABI<Fn, AssertValidValue>();
+    masm.popValue(input);
+    restoreVolatile();
+  }
+
+  masm.bind(&done);
+  masm.pop(temp2);
+  masm.pop(temp1);
+}
+
+void CodeGenerator::emitGCThingResultChecks(LInstruction* lir,
+                                            MDefinition* mir) {
+  if (lir->numDefs() == 0) {
+    return;
+  }
+
+  MOZ_ASSERT(lir->numDefs() == 1);
+  if (lir->getDef(0)->isBogusTemp()) {
+    return;
+  }
+
+  Register output = ToRegister(lir->getDef(0));
+  emitAssertGCThingResult(output, mir);
+}
+
+void CodeGenerator::emitValueResultChecks(LInstruction* lir, MDefinition* mir) {
+  if (lir->numDefs() == 0) {
+    return;
+  }
+
+  MOZ_ASSERT(lir->numDefs() == BOX_PIECES);
+  if (!lir->getDef(0)->output()->isRegister()) {
+    return;
+  }
+
+  ValueOperand output = ToOutValue(lir);
+
+  emitAssertResultV(output, mir);
+}
+
+void CodeGenerator::emitDebugResultChecks(LInstruction* ins) {
+  // In debug builds, check that LIR instructions return valid values.
+
+  MDefinition* mir = ins->mirRaw();
+  if (!mir) {
+    return;
+  }
+
+  switch (mir->type()) {
+    case MIRType::Object:
+    case MIRType::String:
+    case MIRType::Symbol:
+    case MIRType::BigInt:
+      emitGCThingResultChecks(ins, mir);
+      break;
+    case MIRType::Value:
+      emitValueResultChecks(ins, mir);
+      break;
+    default:
+      break;
+  }
+}
+
+void CodeGenerator::emitDebugForceBailing(LInstruction* lir) {
+  if (MOZ_LIKELY(!gen->options.ionBailAfterEnabled())) {
+    return;
+  }
+  if (!lir->snapshot()) {
+    return;
+  }
+  if (lir->isOsiPoint()) {
+    return;
+  }
+
+  masm.comment("emitDebugForceBailing");
+  const void* bailAfterCounterAddr =
+      gen->runtime->addressOfIonBailAfterCounter();
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
+
+  Label done, notBail, bail;
+  masm.branch32(Assembler::Equal, AbsoluteAddress(bailAfterCounterAddr),
+                Imm32(0), &done);
+  {
+    Register temp = regs.takeAny();
+
+    masm.push(temp);
+    masm.load32(AbsoluteAddress(bailAfterCounterAddr), temp);
+    masm.sub32(Imm32(1), temp);
+    masm.store32(temp, AbsoluteAddress(bailAfterCounterAddr));
+
+    masm.branch32(Assembler::NotEqual, temp, Imm32(0), &notBail);
+    {
+      masm.pop(temp);
+      masm.jump(&bail);
+      bailoutFrom(&bail, lir->snapshot());
+    }
+    masm.bind(&notBail);
+    masm.pop(temp);
+  }
+  masm.bind(&done);
+}
+#endif
+
+bool CodeGenerator::generateBody() {
+  JitSpewCont(JitSpew_Codegen, "\n");
+  JitSpew(JitSpew_Codegen, "==== BEGIN CodeGenerator::generateBody ====");
+  IonScriptCounts* counts = maybeCreateScriptCounts();
+
+#if defined(JS_ION_PERF)
+  PerfSpewer* perfSpewer = &perfSpewer_;
+  if (gen->compilingWasm()) {
+    perfSpewer = &gen->perfSpewer();
+  }
+#endif
+
+  for (size_t i = 0; i < graph.numBlocks(); i++) {
+    current = graph.getBlock(i);
+
+    // Don't emit any code for trivial blocks, containing just a goto. Such
+    // blocks are created to split critical edges, and if we didn't end up
+    // putting any instructions in them, we can skip them.
+    if (current->isTrivial()) {
+      continue;
+    }
+
+#ifdef JS_JITSPEW
+    const char* filename = nullptr;
+    size_t lineNumber = 0;
+    unsigned columnNumber = 0;
+    if (current->mir()->info().script()) {
+      filename = current->mir()->info().script()->filename();
+      if (current->mir()->pc()) {
+        lineNumber = PCToLineNumber(current->mir()->info().script(),
+                                    current->mir()->pc(), &columnNumber);
+      }
+    } else {
+#  ifdef DEBUG
+      lineNumber = current->mir()->lineno();
+      columnNumber = current->mir()->columnIndex();
+#  endif
+    }
+    JitSpew(JitSpew_Codegen, "# block%zu %s:%zu:%u%s:", i,
+            filename ? filename : "?", lineNumber, columnNumber,
+            current->mir()->isLoopHeader() ? " (loop header)" : "");
+#endif
+
+    if (current->mir()->isLoopHeader() && gen->compilingWasm()) {
+      masm.nopAlign(CodeAlignment);
+    }
+
+    masm.bind(current->label());
+
+    mozilla::Maybe<ScriptCountBlockState> blockCounts;
+    if (counts) {
+      blockCounts.emplace(&counts->block(i), &masm);
+      if (!blockCounts->init()) {
+        return false;
+      }
+    }
+
+#if defined(JS_ION_PERF)
+    if (!perfSpewer->startBasicBlock(current->mir(), masm)) {
+      return false;
+    }
+#endif
+
+    for (LInstructionIterator iter = current->begin(); iter != current->end();
+         iter++) {
+      if (!alloc().ensureBallast()) {
+        return false;
+      }
+
+#ifdef JS_JITSPEW
+      JitSpewStart(JitSpew_Codegen, "# instruction %s", iter->opName());
+      if (const char* extra = iter->getExtraName()) {
+        JitSpewCont(JitSpew_Codegen, ":%s", extra);
+      }
+      JitSpewFin(JitSpew_Codegen);
+#endif
+
+      if (counts) {
+        blockCounts->visitInstruction(*iter);
+      }
+
+#ifdef CHECK_OSIPOINT_REGISTERS
+      if (iter->safepoint() && !gen->compilingWasm()) {
+        resetOsiPointRegs(iter->safepoint());
+      }
+#endif
+
+      if (iter->mirRaw()) {
+        // Only add instructions that have a tracked inline script tree.
+        if (iter->mirRaw()->trackedTree()) {
+          if (!addNativeToBytecodeEntry(iter->mirRaw()->trackedSite())) {
+            return false;
+          }
+        }
+      }
+
+      setElement(*iter);  // needed to encode correct snapshot location.
+
+#ifdef DEBUG
+      emitDebugForceBailing(*iter);
+#endif
+
+      switch (iter->op()) {
+#ifndef JS_CODEGEN_NONE
+#  define LIROP(op)              \
+    case LNode::Opcode::op:      \
+      visit##op(iter->to##op()); \
+      break;
+        LIR_OPCODE_LIST(LIROP)
+#  undef LIROP
+#endif
+        case LNode::Opcode::Invalid:
+        default:
+          MOZ_CRASH("Invalid LIR op");
+      }
+
+#ifdef DEBUG
+      if (!counts) {
+        emitDebugResultChecks(*iter);
+      }
+#endif
+    }
+    if (masm.oom()) {
+      return false;
+    }
+
+#if defined(JS_ION_PERF)
+    perfSpewer->endBasicBlock(masm);
+#endif
+  }
+
+  JitSpew(JitSpew_Codegen, "==== END CodeGenerator::generateBody ====\n");
+  return true;
+}
+
+// Out-of-line object allocation for LNewArray.
+class OutOfLineNewArray : public OutOfLineCodeBase<CodeGenerator> {
+  LNewArray* lir_;
+
+ public:
+  explicit OutOfLineNewArray(LNewArray* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineNewArray(this);
+  }
+
+  LNewArray* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitNewArrayCallVM(LNewArray* lir) {
+  Register objReg = ToRegister(lir->output());
+
+  MOZ_ASSERT(!lir->isCall());
+  saveLive(lir);
+
+  JSObject* templateObject = lir->mir()->templateObject();
+
+  if (templateObject) {
+    pushArg(ImmGCPtr(templateObject->group()));
+    pushArg(Imm32(lir->mir()->length()));
+
+    using Fn = ArrayObject* (*)(JSContext*, uint32_t, HandleObjectGroup);
+    callVM<Fn, NewArrayWithGroup>(lir);
+  } else {
+    pushArg(Imm32(GenericObject));
+    pushArg(Imm32(lir->mir()->length()));
+
+    using Fn = ArrayObject* (*)(JSContext*, uint32_t, NewObjectKind);
+    callVM<Fn, NewArrayOperation>(lir);
+  }
+
+  if (ReturnReg != objReg) {
+    masm.movePtr(ReturnReg, objReg);
+  }
+
+  restoreLive(lir);
+}
+
+void CodeGenerator::visitAtan2D(LAtan2D* lir) {
+  Register temp = ToRegister(lir->temp());
+  FloatRegister y = ToFloatRegister(lir->y());
+  FloatRegister x = ToFloatRegister(lir->x());
+
+  using Fn = double (*)(double x, double y);
+  masm.setupUnalignedABICall(temp);
+  masm.passABIArg(y, MoveOp::DOUBLE);
+  masm.passABIArg(x, MoveOp::DOUBLE);
+  masm.callWithABI<Fn, ecmaAtan2>(MoveOp::DOUBLE);
+
+  MOZ_ASSERT(ToFloatRegister(lir->output()) == ReturnDoubleReg);
+}
+
+void CodeGenerator::visitHypot(LHypot* lir) {
+  Register temp = ToRegister(lir->temp());
+  uint32_t numArgs = lir->numArgs();
+  masm.setupUnalignedABICall(temp);
+
+  for (uint32_t i = 0; i < numArgs; ++i) {
+    masm.passABIArg(ToFloatRegister(lir->getOperand(i)), MoveOp::DOUBLE);
+  }
+
+  switch (numArgs) {
+    case 2: {
+      using Fn = double (*)(double x, double y);
+      masm.callWithABI<Fn, ecmaHypot>(MoveOp::DOUBLE);
+      break;
+    }
+    case 3: {
+      using Fn = double (*)(double x, double y, double z);
+      masm.callWithABI<Fn, hypot3>(MoveOp::DOUBLE);
+      break;
+    }
+    case 4: {
+      using Fn = double (*)(double x, double y, double z, double w);
+      masm.callWithABI<Fn, hypot4>(MoveOp::DOUBLE);
+      break;
+    }
+    default:
+      MOZ_CRASH("Unexpected number of arguments to hypot function.");
+  }
+  MOZ_ASSERT(ToFloatRegister(lir->output()) == ReturnDoubleReg);
+}
+
+void CodeGenerator::visitNewArray(LNewArray* lir) {
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+  DebugOnly<uint32_t> length = lir->mir()->length();
+
+  MOZ_ASSERT(length <= NativeObject::MAX_DENSE_ELEMENTS_COUNT);
+
+  if (lir->mir()->isVMCall()) {
+    visitNewArrayCallVM(lir);
+    return;
+  }
+
+  OutOfLineNewArray* ool = new (alloc()) OutOfLineNewArray(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  TemplateObject templateObject(lir->mir()->templateObject());
+#ifdef DEBUG
+  size_t numInlineElements = gc::GetGCKindSlots(templateObject.getAllocKind()) -
+                             ObjectElements::VALUES_PER_HEADER;
+  MOZ_ASSERT(length <= numInlineElements,
+             "Inline allocation only supports inline elements");
+#endif
+  masm.createGCObject(objReg, tempReg, templateObject,
+                      lir->mir()->initialHeap(), ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineNewArray(OutOfLineNewArray* ool) {
+  visitNewArrayCallVM(ool->lir());
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitNewArrayDynamicLength(LNewArrayDynamicLength* lir) {
+  Register lengthReg = ToRegister(lir->length());
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+
+  JSObject* templateObject = lir->mir()->templateObject();
+  gc::InitialHeap initialHeap = lir->mir()->initialHeap();
+
+  using Fn = ArrayObject* (*)(JSContext*, HandleArrayObject, int32_t length);
+  OutOfLineCode* ool = oolCallVM<Fn, ArrayConstructorOneArg>(
+      lir, ArgList(ImmGCPtr(templateObject), lengthReg),
+      StoreRegisterTo(objReg));
+
+  bool canInline = true;
+  size_t inlineLength = 0;
+  if (templateObject->as<ArrayObject>().hasFixedElements()) {
+    size_t numSlots =
+        gc::GetGCKindSlots(templateObject->asTenured().getAllocKind());
+    inlineLength = numSlots - ObjectElements::VALUES_PER_HEADER;
+  } else {
+    canInline = false;
+  }
+
+  if (canInline) {
+    // Try to do the allocation inline if the template object is big enough
+    // for the length in lengthReg. If the length is bigger we could still
+    // use the template object and not allocate the elements, but it's more
+    // efficient to do a single big allocation than (repeatedly) reallocating
+    // the array later on when filling it.
+    masm.branch32(Assembler::Above, lengthReg, Imm32(inlineLength),
+                  ool->entry());
+
+    TemplateObject templateObj(templateObject);
+    masm.createGCObject(objReg, tempReg, templateObj, initialHeap,
+                        ool->entry());
+
+    size_t lengthOffset = NativeObject::offsetOfFixedElements() +
+                          ObjectElements::offsetOfLength();
+    masm.store32(lengthReg, Address(objReg, lengthOffset));
+  } else {
+    masm.jump(ool->entry());
+  }
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewIterator(LNewIterator* lir) {
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+
+  OutOfLineCode* ool;
+  switch (lir->mir()->type()) {
+    case MNewIterator::ArrayIterator: {
+      using Fn = ArrayIteratorObject* (*)(JSContext*);
+      ool = oolCallVM<Fn, NewArrayIterator>(lir, ArgList(),
+                                            StoreRegisterTo(objReg));
+      break;
+    }
+    case MNewIterator::StringIterator: {
+      using Fn = StringIteratorObject* (*)(JSContext*);
+      ool = oolCallVM<Fn, NewStringIterator>(lir, ArgList(),
+                                             StoreRegisterTo(objReg));
+      break;
+    }
+    case MNewIterator::RegExpStringIterator: {
+      using Fn = RegExpStringIteratorObject* (*)(JSContext*);
+      ool = oolCallVM<Fn, NewRegExpStringIterator>(lir, ArgList(),
+                                                   StoreRegisterTo(objReg));
+      break;
+    }
+    default:
+      MOZ_CRASH("unexpected iterator type");
+  }
+
+  TemplateObject templateObject(lir->mir()->templateObject());
+  masm.createGCObject(objReg, tempReg, templateObject, gc::DefaultHeap,
+                      ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewTypedArray(LNewTypedArray* lir) {
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp1());
+  Register lengthReg = ToRegister(lir->temp2());
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+
+  JSObject* templateObject = lir->mir()->templateObject();
+  gc::InitialHeap initialHeap = lir->mir()->initialHeap();
+
+  TypedArrayObject* ttemplate = &templateObject->as<TypedArrayObject>();
+  uint32_t n = ttemplate->length().deprecatedGetUint32();
+
+  using Fn = TypedArrayObject* (*)(JSContext*, HandleObject, int32_t length);
+  OutOfLineCode* ool = oolCallVM<Fn, NewTypedArrayWithTemplateAndLength>(
+      lir, ArgList(ImmGCPtr(templateObject), Imm32(n)),
+      StoreRegisterTo(objReg));
+
+  TemplateObject templateObj(templateObject);
+  masm.createGCObject(objReg, tempReg, templateObj, initialHeap, ool->entry());
+
+  masm.initTypedArraySlots(objReg, tempReg, lengthReg, liveRegs, ool->entry(),
+                           ttemplate, MacroAssembler::TypedArrayLength::Fixed);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewTypedArrayDynamicLength(
+    LNewTypedArrayDynamicLength* lir) {
+  Register lengthReg = ToRegister(lir->length());
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+
+  JSObject* templateObject = lir->mir()->templateObject();
+  gc::InitialHeap initialHeap = lir->mir()->initialHeap();
+
+  TypedArrayObject* ttemplate = &templateObject->as<TypedArrayObject>();
+
+  using Fn = TypedArrayObject* (*)(JSContext*, HandleObject, int32_t length);
+  OutOfLineCode* ool = oolCallVM<Fn, NewTypedArrayWithTemplateAndLength>(
+      lir, ArgList(ImmGCPtr(templateObject), lengthReg),
+      StoreRegisterTo(objReg));
+
+  TemplateObject templateObj(templateObject);
+  masm.createGCObject(objReg, tempReg, templateObj, initialHeap, ool->entry());
+
+  masm.initTypedArraySlots(objReg, tempReg, lengthReg, liveRegs, ool->entry(),
+                           ttemplate,
+                           MacroAssembler::TypedArrayLength::Dynamic);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewTypedArrayFromArray(LNewTypedArrayFromArray* lir) {
+  pushArg(ToRegister(lir->array()));
+  pushArg(ImmGCPtr(lir->mir()->templateObject()));
+
+  using Fn = TypedArrayObject* (*)(JSContext*, HandleObject, HandleObject);
+  callVM<Fn, js::NewTypedArrayWithTemplateAndArray>(lir);
+}
+
+void CodeGenerator::visitNewTypedArrayFromArrayBuffer(
+    LNewTypedArrayFromArrayBuffer* lir) {
+  pushArg(ToValue(lir, LNewTypedArrayFromArrayBuffer::LengthIndex));
+  pushArg(ToValue(lir, LNewTypedArrayFromArrayBuffer::ByteOffsetIndex));
+  pushArg(ToRegister(lir->arrayBuffer()));
+  pushArg(ImmGCPtr(lir->mir()->templateObject()));
+
+  using Fn = TypedArrayObject* (*)(JSContext*, HandleObject, HandleObject,
+                                   HandleValue, HandleValue);
+  callVM<Fn, js::NewTypedArrayWithTemplateAndBuffer>(lir);
+}
+
+// Out-of-line object allocation for JSOp::NewObject.
+class OutOfLineNewObject : public OutOfLineCodeBase<CodeGenerator> {
+  LNewObject* lir_;
+
+ public:
+  explicit OutOfLineNewObject(LNewObject* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineNewObject(this);
+  }
+
+  LNewObject* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitNewObjectVMCall(LNewObject* lir) {
+  Register objReg = ToRegister(lir->output());
+
+  MOZ_ASSERT(!lir->isCall());
+  saveLive(lir);
+
+  JSObject* templateObject = lir->mir()->templateObject();
+
+  // If we're making a new object with a class prototype (that is, an object
+  // that derives its class from its prototype instead of being
+  // PlainObject::class_'d) from self-hosted code, we need a different init
+  // function.
+  switch (lir->mir()->mode()) {
+    case MNewObject::ObjectLiteral:
+      if (templateObject) {
+        pushArg(ImmGCPtr(templateObject));
+
+        using Fn = JSObject* (*)(JSContext*, HandleObject);
+        callVM<Fn, NewObjectOperationWithTemplate>(lir);
+      } else {
+        pushArg(Imm32(GenericObject));
+        pushArg(ImmPtr(lir->mir()->resumePoint()->pc()));
+        pushArg(ImmGCPtr(lir->mir()->block()->info().script()));
+
+        using Fn = JSObject* (*)(JSContext*, HandleScript, jsbytecode * pc,
+                                 NewObjectKind);
+        callVM<Fn, NewObjectOperation>(lir);
+      }
+      break;
+    case MNewObject::ObjectCreate:
+      pushArg(ImmGCPtr(templateObject));
+
+      using Fn = PlainObject* (*)(JSContext*, HandlePlainObject);
+      callVM<Fn, ObjectCreateWithTemplate>(lir);
+      break;
+  }
+
+  if (ReturnReg != objReg) {
+    masm.movePtr(ReturnReg, objReg);
+  }
+
+  restoreLive(lir);
+}
+
+static bool ShouldInitFixedSlots(LInstruction* lir, const TemplateObject& obj) {
+  if (!obj.isNative()) {
+    return true;
+  }
+  const NativeTemplateObject& templateObj = obj.asNativeTemplateObject();
+
+  // Look for StoreFixedSlot instructions following an object allocation
+  // that write to this object before a GC is triggered or this object is
+  // passed to a VM call. If all fixed slots will be initialized, the
+  // allocation code doesn't need to set the slots to |undefined|.
+
+  uint32_t nfixed = templateObj.numUsedFixedSlots();
+  if (nfixed == 0) {
+    return false;
+  }
+
+  // Only optimize if all fixed slots are initially |undefined|, so that we
+  // can assume incremental pre-barriers are not necessary. See also the
+  // comment below.
+  for (uint32_t slot = 0; slot < nfixed; slot++) {
+    if (!templateObj.getSlot(slot).isUndefined()) {
+      return true;
+    }
+  }
+
+  // Keep track of the fixed slots that are initialized. initializedSlots is
+  // a bit mask with a bit for each slot.
+  MOZ_ASSERT(nfixed <= NativeObject::MAX_FIXED_SLOTS);
+  static_assert(NativeObject::MAX_FIXED_SLOTS <= 32,
+                "Slot bits must fit in 32 bits");
+  uint32_t initializedSlots = 0;
+  uint32_t numInitialized = 0;
+
+  MInstruction* allocMir = lir->mirRaw()->toInstruction();
+  MBasicBlock* block = allocMir->block();
+
+  // Skip the allocation instruction.
+  MInstructionIterator iter = block->begin(allocMir);
+  MOZ_ASSERT(*iter == allocMir);
+  iter++;
+
+  while (true) {
+    for (; iter != block->end(); iter++) {
+      if (iter->isNop() || iter->isConstant() || iter->isPostWriteBarrier()) {
+        // These instructions won't trigger a GC or read object slots.
+        continue;
+      }
+
+      if (iter->isStoreFixedSlot()) {
+        MStoreFixedSlot* store = iter->toStoreFixedSlot();
+        if (store->object() != allocMir) {
+          return true;
+        }
+
+        // We may not initialize this object slot on allocation, so the
+        // pre-barrier could read uninitialized memory. Simply disable
+        // the barrier for this store: the object was just initialized
+        // so the barrier is not necessary.
+        store->setNeedsBarrier(false);
+
+        uint32_t slot = store->slot();
+        MOZ_ASSERT(slot < nfixed);
+        if ((initializedSlots & (1 << slot)) == 0) {
+          numInitialized++;
+          initializedSlots |= (1 << slot);
+
+          if (numInitialized == nfixed) {
+            // All fixed slots will be initialized.
+            MOZ_ASSERT(mozilla::CountPopulation32(initializedSlots) == nfixed);
+            return false;
+          }
+        }
+        continue;
+      }
+
+      if (iter->isGoto()) {
+        block = iter->toGoto()->target();
+        if (block->numPredecessors() != 1) {
+          return true;
+        }
+        break;
+      }
+
+      // Unhandled instruction, assume it bails or reads object slots.
+      return true;
+    }
+    iter = block->begin();
+  }
+
+  MOZ_CRASH("Shouldn't get here");
+}
+
+void CodeGenerator::visitNewObject(LNewObject* lir) {
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+
+  if (lir->mir()->isVMCall()) {
+    visitNewObjectVMCall(lir);
+    return;
+  }
+
+  OutOfLineNewObject* ool = new (alloc()) OutOfLineNewObject(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  TemplateObject templateObject(lir->mir()->templateObject());
+
+  bool initContents = ShouldInitFixedSlots(lir, templateObject);
+  masm.createGCObject(objReg, tempReg, templateObject,
+                      lir->mir()->initialHeap(), ool->entry(), initContents);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineNewObject(OutOfLineNewObject* ool) {
+  visitNewObjectVMCall(ool->lir());
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitNewNamedLambdaObject(LNewNamedLambdaObject* lir) {
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+  const CompileInfo& info = lir->mir()->block()->info();
+
+  // If we have a template object, we can inline call object creation.
+  using Fn =
+      js::NamedLambdaObject* (*)(JSContext*, HandleFunction, gc::InitialHeap);
+  OutOfLineCode* ool = oolCallVM<Fn, NamedLambdaObject::createTemplateObject>(
+      lir, ArgList(ImmGCPtr(info.funMaybeLazy()), Imm32(gc::DefaultHeap)),
+      StoreRegisterTo(objReg));
+
+  TemplateObject templateObject(lir->mir()->templateObj());
+
+  bool initContents = ShouldInitFixedSlots(lir, templateObject);
+  masm.createGCObject(objReg, tempReg, templateObject, gc::DefaultHeap,
+                      ool->entry(), initContents);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewCallObject(LNewCallObject* lir) {
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+
+  CallObject* templateObj = lir->mir()->templateObject();
+
+  using Fn = JSObject* (*)(JSContext*, HandleShape, HandleObjectGroup);
+  OutOfLineCode* ool = oolCallVM<Fn, NewCallObject>(
+      lir,
+      ArgList(ImmGCPtr(templateObj->lastProperty()),
+              ImmGCPtr(templateObj->group())),
+      StoreRegisterTo(objReg));
+
+  // Inline call object creation, using the OOL path only for tricky cases.
+  TemplateObject templateObject(templateObj);
+  bool initContents = ShouldInitFixedSlots(lir, templateObject);
+  masm.createGCObject(objReg, tempReg, templateObject, gc::DefaultHeap,
+                      ool->entry(), initContents);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitNewStringObject(LNewStringObject* lir) {
+  Register input = ToRegister(lir->input());
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+
+  StringObject* templateObj = lir->mir()->templateObj();
+
+  using Fn = JSObject* (*)(JSContext*, HandleString);
+  OutOfLineCode* ool = oolCallVM<Fn, NewStringObject>(lir, ArgList(input),
+                                                      StoreRegisterTo(output));
+
+  TemplateObject templateObject(templateObj);
+  masm.createGCObject(output, temp, templateObject, gc::DefaultHeap,
+                      ool->entry());
+
+  masm.loadStringLength(input, temp);
+
+  masm.storeValue(JSVAL_TYPE_STRING, input,
+                  Address(output, StringObject::offsetOfPrimitiveValue()));
+  masm.storeValue(JSVAL_TYPE_INT32, temp,
+                  Address(output, StringObject::offsetOfLength()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitInitElemGetterSetter(LInitElemGetterSetter* lir) {
+  Register obj = ToRegister(lir->object());
+  Register value = ToRegister(lir->value());
+
+  pushArg(value);
+  pushArg(ToValue(lir, LInitElemGetterSetter::IdIndex));
+  pushArg(obj);
+  pushArg(ImmPtr(lir->mir()->resumePoint()->pc()));
+
+  using Fn = bool (*)(JSContext*, jsbytecode*, HandleObject, HandleValue,
+                      HandleObject);
+  callVM<Fn, InitElemGetterSetterOperation>(lir);
+}
+
+void CodeGenerator::visitMutateProto(LMutateProto* lir) {
+  Register objReg = ToRegister(lir->getObject());
+
+  pushArg(ToValue(lir, LMutateProto::ValueIndex));
+  pushArg(objReg);
+
+  using Fn = bool (*)(JSContext * cx, HandlePlainObject obj, HandleValue value);
+  callVM<Fn, MutatePrototype>(lir);
+}
+
+void CodeGenerator::visitInitPropGetterSetter(LInitPropGetterSetter* lir) {
+  Register obj = ToRegister(lir->object());
+  Register value = ToRegister(lir->value());
+
+  pushArg(value);
+  pushArg(ImmGCPtr(lir->mir()->name()));
+  pushArg(obj);
+  pushArg(ImmPtr(lir->mir()->resumePoint()->pc()));
+
+  using Fn = bool (*)(JSContext*, jsbytecode*, HandleObject, HandlePropertyName,
+                      HandleObject);
+  callVM<Fn, InitPropGetterSetterOperation>(lir);
+}
+
+void CodeGenerator::visitCreateThis(LCreateThis* lir) {
+  const LAllocation* callee = lir->getCallee();
+  const LAllocation* newTarget = lir->getNewTarget();
+
+  if (newTarget->isConstant()) {
+    pushArg(ImmGCPtr(&newTarget->toConstant()->toObject()));
+  } else {
+    pushArg(ToRegister(newTarget));
+  }
+
+  if (callee->isConstant()) {
+    pushArg(ImmGCPtr(&callee->toConstant()->toObject()));
+  } else {
+    pushArg(ToRegister(callee));
+  }
+
+  using Fn = bool (*)(JSContext * cx, HandleObject callee,
+                      HandleObject newTarget, MutableHandleValue rval);
+  callVM<Fn, jit::CreateThisFromIon>(lir);
+}
+
+void CodeGenerator::visitCreateThisWithTemplate(LCreateThisWithTemplate* lir) {
+  JSObject* templateObject = lir->mir()->templateObject();
+  Register objReg = ToRegister(lir->output());
+  Register tempReg = ToRegister(lir->temp());
+
+  using Fn = JSObject* (*)(JSContext*, HandleObject);
+  OutOfLineCode* ool = oolCallVM<Fn, CreateThisWithTemplate>(
+      lir, ArgList(ImmGCPtr(templateObject)), StoreRegisterTo(objReg));
+
+  // Allocate. If the FreeList is empty, call to VM, which may GC.
+  TemplateObject templateObj(templateObject);
+  bool initContents =
+      !templateObj.isPlainObject() || ShouldInitFixedSlots(lir, templateObj);
+  masm.createGCObject(objReg, tempReg, templateObj, lir->mir()->initialHeap(),
+                      ool->entry(), initContents);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCreateArgumentsObject(LCreateArgumentsObject* lir) {
+  // This should be getting constructed in the first block only, and not any OSR
+  // entry blocks.
+  MOZ_ASSERT(lir->mir()->block()->id() == 0);
+
+  Register callObj = ToRegister(lir->getCallObject());
+  Register temp = ToRegister(lir->temp0());
+  Label done;
+
+  if (ArgumentsObject* templateObj = lir->mir()->templateObject()) {
+    Register objTemp = ToRegister(lir->temp1());
+    Register cxTemp = ToRegister(lir->temp2());
+
+    masm.Push(callObj);
+
+    // Try to allocate an arguments object. This will leave the reserved
+    // slots uninitialized, so it's important we don't GC until we
+    // initialize these slots in ArgumentsObject::finishForIonPure.
+    Label failure;
+    TemplateObject templateObject(templateObj);
+    masm.createGCObject(objTemp, temp, templateObject, gc::DefaultHeap,
+                        &failure,
+                        /* initContents = */ false);
+
+    masm.moveStackPtrTo(temp);
+    masm.addPtr(Imm32(masm.framePushed()), temp);
+
+    using Fn =
+        ArgumentsObject* (*)(JSContext * cx, jit::JitFrameLayout * frame,
+                             JSObject * scopeChain, ArgumentsObject * obj);
+    masm.setupUnalignedABICall(cxTemp);
+    masm.loadJSContext(cxTemp);
+    masm.passABIArg(cxTemp);
+    masm.passABIArg(temp);
+    masm.passABIArg(callObj);
+    masm.passABIArg(objTemp);
+
+    masm.callWithABI<Fn, ArgumentsObject::finishForIonPure>();
+    masm.branchTestPtr(Assembler::Zero, ReturnReg, ReturnReg, &failure);
+
+    // Discard saved callObj on the stack.
+    masm.addToStackPtr(Imm32(sizeof(uintptr_t)));
+    masm.jump(&done);
+
+    masm.bind(&failure);
+    masm.Pop(callObj);
+  }
+
+  masm.moveStackPtrTo(temp);
+  masm.addPtr(Imm32(frameSize()), temp);
+
+  pushArg(callObj);
+  pushArg(temp);
+
+  using Fn = ArgumentsObject* (*)(JSContext*, JitFrameLayout*, HandleObject);
+  callVM<Fn, ArgumentsObject::createForIon>(lir);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitGetArgumentsObjectArg(LGetArgumentsObjectArg* lir) {
+  Register temp = ToRegister(lir->getTemp(0));
+  Register argsObj = ToRegister(lir->getArgsObject());
+  ValueOperand out = ToOutValue(lir);
+
+  masm.loadPrivate(Address(argsObj, ArgumentsObject::getDataSlotOffset()),
+                   temp);
+  Address argAddr(temp, ArgumentsData::offsetOfArgs() +
+                            lir->mir()->argno() * sizeof(Value));
+  masm.loadValue(argAddr, out);
+#ifdef DEBUG
+  Label success;
+  masm.branchTestMagic(Assembler::NotEqual, out, &success);
+  masm.assumeUnreachable(
+      "Result from ArgumentObject shouldn't be JSVAL_TYPE_MAGIC.");
+  masm.bind(&success);
+#endif
+}
+
+void CodeGenerator::visitSetArgumentsObjectArg(LSetArgumentsObjectArg* lir) {
+  Register temp = ToRegister(lir->getTemp(0));
+  Register argsObj = ToRegister(lir->getArgsObject());
+  ValueOperand value = ToValue(lir, LSetArgumentsObjectArg::ValueIndex);
+
+  masm.loadPrivate(Address(argsObj, ArgumentsObject::getDataSlotOffset()),
+                   temp);
+  Address argAddr(temp, ArgumentsData::offsetOfArgs() +
+                            lir->mir()->argno() * sizeof(Value));
+  emitPreBarrier(argAddr);
+#ifdef DEBUG
+  Label success;
+  masm.branchTestMagic(Assembler::NotEqual, argAddr, &success);
+  masm.assumeUnreachable(
+      "Result in ArgumentObject shouldn't be JSVAL_TYPE_MAGIC.");
+  masm.bind(&success);
+#endif
+  masm.storeValue(value, argAddr);
+}
+
+void CodeGenerator::visitLoadArgumentsObjectArg(LLoadArgumentsObjectArg* lir) {
+  Register temp = ToRegister(lir->temp());
+  Register argsObj = ToRegister(lir->getArgsObject());
+  Register index = ToRegister(lir->index());
+  ValueOperand out = ToOutValue(lir);
+
+  Label bail;
+  masm.loadArgumentsObjectElement(argsObj, index, out, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitArgumentsObjectLength(LArgumentsObjectLength* lir) {
+  Register argsObj = ToRegister(lir->getArgsObject());
+  Register out = ToRegister(lir->output());
+
+  Label bail;
+  masm.loadArgumentsObjectLength(argsObj, out, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardArgumentsObjectNotOverriddenIterator(
+    LGuardArgumentsObjectNotOverriddenIterator* lir) {
+  Register argsObj = ToRegister(lir->getArgsObject());
+  Register temp = ToRegister(lir->temp());
+
+  Label bail;
+  masm.branchArgumentsObjectHasOverridenIterator(argsObj, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitReturnFromCtor(LReturnFromCtor* lir) {
+  ValueOperand value = ToValue(lir, LReturnFromCtor::ValueIndex);
+  Register obj = ToRegister(lir->getObject());
+  Register output = ToRegister(lir->output());
+
+  Label valueIsObject, end;
+
+  masm.branchTestObject(Assembler::Equal, value, &valueIsObject);
+
+  // Value is not an object. Return that other object.
+  masm.movePtr(obj, output);
+  masm.jump(&end);
+
+  // Value is an object. Return unbox(Value).
+  masm.bind(&valueIsObject);
+  Register payload = masm.extractObject(value, output);
+  if (payload != output) {
+    masm.movePtr(payload, output);
+  }
+
+  masm.bind(&end);
+}
+
+class OutOfLineBoxNonStrictThis : public OutOfLineCodeBase<CodeGenerator> {
+  LBoxNonStrictThis* ins_;
+
+ public:
+  explicit OutOfLineBoxNonStrictThis(LBoxNonStrictThis* ins) : ins_(ins) {}
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineBoxNonStrictThis(this);
+  }
+  LBoxNonStrictThis* ins() const { return ins_; }
+};
+
+void CodeGenerator::visitBoxNonStrictThis(LBoxNonStrictThis* lir) {
+  ValueOperand value = ToValue(lir, LBoxNonStrictThis::ValueIndex);
+  Register output = ToRegister(lir->output());
+
+  auto* ool = new (alloc()) OutOfLineBoxNonStrictThis(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  masm.fallibleUnboxObject(value, output, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineBoxNonStrictThis(
+    OutOfLineBoxNonStrictThis* ool) {
+  LBoxNonStrictThis* lir = ool->ins();
+
+  ValueOperand value = ToValue(lir, LBoxNonStrictThis::ValueIndex);
+  Register output = ToRegister(lir->output());
+
+  Label notNullOrUndefined;
+  {
+    Label isNullOrUndefined;
+    ScratchTagScope tag(masm, value);
+    masm.splitTagForTest(value, tag);
+    masm.branchTestUndefined(Assembler::Equal, tag, &isNullOrUndefined);
+    masm.branchTestNull(Assembler::NotEqual, tag, &notNullOrUndefined);
+    masm.bind(&isNullOrUndefined);
+    masm.movePtr(ImmGCPtr(lir->mir()->globalThis()), output);
+    masm.jump(ool->rejoin());
+  }
+
+  masm.bind(&notNullOrUndefined);
+
+  saveLive(lir);
+
+  pushArg(value);
+  using Fn = JSObject* (*)(JSContext*, HandleValue);
+  callVM<Fn, BoxNonStrictThis>(lir);
+
+  StoreRegisterTo(output).generate(this);
+  restoreLiveIgnore(lir, StoreRegisterTo(output).clobbered());
+
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitImplicitThis(LImplicitThis* lir) {
+  pushArg(ImmGCPtr(lir->mir()->name()));
+  pushArg(ToRegister(lir->env()));
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandlePropertyName,
+                      MutableHandleValue);
+  callVM<Fn, ImplicitThisOperation>(lir);
+}
+
+void CodeGenerator::visitArrowNewTarget(LArrowNewTarget* lir) {
+  Register callee = ToRegister(lir->callee());
+  ValueOperand output = ToOutValue(lir);
+  masm.loadValue(
+      Address(callee, FunctionExtended::offsetOfArrowNewTargetSlot()), output);
+}
+
+void CodeGenerator::visitArrayLength(LArrayLength* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register output = ToRegister(lir->output());
+
+  Address length(elements, ObjectElements::offsetOfLength());
+  masm.load32(length, output);
+
+  // Bail out if the length doesn't fit in int32.
+  Label bail;
+  masm.branchTest32(Assembler::Signed, output, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+static void SetLengthFromIndex(MacroAssembler& masm, const LAllocation* index,
+                               const Address& length) {
+  if (index->isConstant()) {
+    masm.store32(Imm32(ToInt32(index) + 1), length);
+  } else {
+    Register newLength = ToRegister(index);
+    masm.add32(Imm32(1), newLength);
+    masm.store32(newLength, length);
+    masm.sub32(Imm32(1), newLength);
+  }
+}
+
+void CodeGenerator::visitSetArrayLength(LSetArrayLength* lir) {
+  Address length(ToRegister(lir->elements()), ObjectElements::offsetOfLength());
+  SetLengthFromIndex(masm, lir->index(), length);
+}
+
+void CodeGenerator::visitFunctionLength(LFunctionLength* lir) {
+  Register function = ToRegister(lir->function());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+
+  // Get the JSFunction flags.
+  masm.load16ZeroExtend(Address(function, JSFunction::offsetOfFlags()), output);
+
+  // Functions with a SelfHostedLazyScript must be compiled with the slow-path
+  // before the function length is known. If the length was previously resolved,
+  // the length property may be shadowed.
+  masm.branchTest32(
+      Assembler::NonZero, output,
+      Imm32(FunctionFlags::SELFHOSTLAZY | FunctionFlags::RESOLVED_LENGTH),
+      &bail);
+
+  masm.loadFunctionLength(function, output, output, &bail);
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitFunctionName(LFunctionName* lir) {
+  Register function = ToRegister(lir->function());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+
+  const JSAtomState& names = gen->runtime->names();
+  masm.loadFunctionName(function, output, ImmGCPtr(names.empty), &bail);
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+template <class OrderedHashTable>
+static void RangeFront(MacroAssembler&, Register, Register, Register);
+
+template <>
+void RangeFront<ValueMap>(MacroAssembler& masm, Register range, Register i,
+                          Register front) {
+  masm.loadPtr(Address(range, ValueMap::Range::offsetOfHashTable()), front);
+  masm.loadPtr(Address(front, ValueMap::offsetOfImplData()), front);
+
+  MOZ_ASSERT(ValueMap::offsetOfImplDataElement() == 0,
+             "offsetof(Data, element) is 0");
+  static_assert(ValueMap::sizeofImplData() == 24, "sizeof(Data) is 24");
+  masm.mulBy3(i, i);
+  masm.lshiftPtr(Imm32(3), i);
+  masm.addPtr(i, front);
+}
+
+template <>
+void RangeFront<ValueSet>(MacroAssembler& masm, Register range, Register i,
+                          Register front) {
+  masm.loadPtr(Address(range, ValueSet::Range::offsetOfHashTable()), front);
+  masm.loadPtr(Address(front, ValueSet::offsetOfImplData()), front);
+
+  MOZ_ASSERT(ValueSet::offsetOfImplDataElement() == 0,
+             "offsetof(Data, element) is 0");
+  static_assert(ValueSet::sizeofImplData() == 16, "sizeof(Data) is 16");
+  masm.lshiftPtr(Imm32(4), i);
+  masm.addPtr(i, front);
+}
+
+template <class OrderedHashTable>
+static void RangePopFront(MacroAssembler& masm, Register range, Register front,
+                          Register dataLength, Register temp) {
+  Register i = temp;
+
+  masm.add32(Imm32(1),
+             Address(range, OrderedHashTable::Range::offsetOfCount()));
+
+  masm.load32(Address(range, OrderedHashTable::Range::offsetOfI()), i);
+
+  Label done, seek;
+  masm.bind(&seek);
+  masm.add32(Imm32(1), i);
+  masm.branch32(Assembler::AboveOrEqual, i, dataLength, &done);
+
+  // We can add sizeof(Data) to |front| to select the next element, because
+  // |front| and |range.ht.data[i]| point to the same location.
+  MOZ_ASSERT(OrderedHashTable::offsetOfImplDataElement() == 0,
+             "offsetof(Data, element) is 0");
+  masm.addPtr(Imm32(OrderedHashTable::sizeofImplData()), front);
+
+  masm.branchTestMagic(Assembler::Equal,
+                       Address(front, OrderedHashTable::offsetOfEntryKey()),
+                       JS_HASH_KEY_EMPTY, &seek);
+
+  masm.bind(&done);
+  masm.store32(i, Address(range, OrderedHashTable::Range::offsetOfI()));
+}
+
+template <class OrderedHashTable>
+static inline void RangeDestruct(MacroAssembler& masm, Register iter,
+                                 Register range, Register temp0,
+                                 Register temp1) {
+  Register next = temp0;
+  Register prevp = temp1;
+
+  masm.loadPtr(Address(range, OrderedHashTable::Range::offsetOfNext()), next);
+  masm.loadPtr(Address(range, OrderedHashTable::Range::offsetOfPrevP()), prevp);
+  masm.storePtr(next, Address(prevp, 0));
+
+  Label hasNoNext;
+  masm.branchTestPtr(Assembler::Zero, next, next, &hasNoNext);
+
+  masm.storePtr(prevp, Address(next, OrderedHashTable::Range::offsetOfPrevP()));
+
+  masm.bind(&hasNoNext);
+
+  Label nurseryAllocated;
+  masm.branchPtrInNurseryChunk(Assembler::Equal, iter, temp0,
+                               &nurseryAllocated);
+
+  masm.callFreeStub(range);
+
+  masm.bind(&nurseryAllocated);
+}
+
+template <>
+void CodeGenerator::emitLoadIteratorValues<ValueMap>(Register result,
+                                                     Register temp,
+                                                     Register front) {
+  size_t elementsOffset = NativeObject::offsetOfFixedElements();
+
+  Address keyAddress(front, ValueMap::Entry::offsetOfKey());
+  Address valueAddress(front, ValueMap::Entry::offsetOfValue());
+  Address keyElemAddress(result, elementsOffset);
+  Address valueElemAddress(result, elementsOffset + sizeof(Value));
+  masm.guardedCallPreBarrier(keyElemAddress, MIRType::Value);
+  masm.guardedCallPreBarrier(valueElemAddress, MIRType::Value);
+  masm.storeValue(keyAddress, keyElemAddress, temp);
+  masm.storeValue(valueAddress, valueElemAddress, temp);
+
+  Label emitBarrier, skipBarrier;
+  masm.branchValueIsNurseryCell(Assembler::Equal, keyAddress, temp,
+                                &emitBarrier);
+  masm.branchValueIsNurseryCell(Assembler::NotEqual, valueAddress, temp,
+                                &skipBarrier);
+  {
+    masm.bind(&emitBarrier);
+    saveVolatile(temp);
+    emitPostWriteBarrier(result);
+    restoreVolatile(temp);
+  }
+  masm.bind(&skipBarrier);
+}
+
+template <>
+void CodeGenerator::emitLoadIteratorValues<ValueSet>(Register result,
+                                                     Register temp,
+                                                     Register front) {
+  size_t elementsOffset = NativeObject::offsetOfFixedElements();
+
+  Address keyAddress(front, ValueSet::offsetOfEntryKey());
+  Address keyElemAddress(result, elementsOffset);
+  masm.guardedCallPreBarrier(keyElemAddress, MIRType::Value);
+  masm.storeValue(keyAddress, keyElemAddress, temp);
+
+  Label skipBarrier;
+  masm.branchValueIsNurseryCell(Assembler::NotEqual, keyAddress, temp,
+                                &skipBarrier);
+  {
+    saveVolatile(temp);
+    emitPostWriteBarrier(result);
+    restoreVolatile(temp);
+  }
+  masm.bind(&skipBarrier);
+}
+
+template <class IteratorObject, class OrderedHashTable>
+void CodeGenerator::emitGetNextEntryForIterator(LGetNextEntryForIterator* lir) {
+  Register iter = ToRegister(lir->iter());
+  Register result = ToRegister(lir->result());
+  Register temp = ToRegister(lir->temp0());
+  Register dataLength = ToRegister(lir->temp1());
+  Register range = ToRegister(lir->temp2());
+  Register output = ToRegister(lir->output());
+
+#ifdef DEBUG
+  // Self-hosted code is responsible for ensuring GetNextEntryForIterator is
+  // only called with the correct iterator class. Assert here all self-
+  // hosted callers of GetNextEntryForIterator perform this class check.
+  // No Spectre mitigations are needed because this is DEBUG-only code.
+  Label success;
+  masm.branchTestObjClassNoSpectreMitigations(
+      Assembler::Equal, iter, &IteratorObject::class_, temp, &success);
+  masm.assumeUnreachable("Iterator object should have the correct class.");
+  masm.bind(&success);
+#endif
+
+  masm.loadPrivate(Address(iter, NativeObject::getFixedSlotOffset(
+                                     IteratorObject::RangeSlot)),
+                   range);
+
+  Label iterAlreadyDone, iterDone, done;
+  masm.branchTestPtr(Assembler::Zero, range, range, &iterAlreadyDone);
+
+  masm.load32(Address(range, OrderedHashTable::Range::offsetOfI()), temp);
+  masm.loadPtr(Address(range, OrderedHashTable::Range::offsetOfHashTable()),
+               dataLength);
+  masm.load32(Address(dataLength, OrderedHashTable::offsetOfImplDataLength()),
+              dataLength);
+  masm.branch32(Assembler::AboveOrEqual, temp, dataLength, &iterDone);
+  {
+    masm.push(iter);
+
+    Register front = iter;
+    RangeFront<OrderedHashTable>(masm, range, temp, front);
+
+    emitLoadIteratorValues<OrderedHashTable>(result, temp, front);
+
+    RangePopFront<OrderedHashTable>(masm, range, front, dataLength, temp);
+
+    masm.pop(iter);
+    masm.move32(Imm32(0), output);
+  }
+  masm.jump(&done);
+  {
+    masm.bind(&iterDone);
+
+    RangeDestruct<OrderedHashTable>(masm, iter, range, temp, dataLength);
+
+    masm.storeValue(PrivateValue(nullptr),
+                    Address(iter, NativeObject::getFixedSlotOffset(
+                                      IteratorObject::RangeSlot)));
+
+    masm.bind(&iterAlreadyDone);
+
+    masm.move32(Imm32(1), output);
+  }
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitGetNextEntryForIterator(
+    LGetNextEntryForIterator* lir) {
+  if (lir->mir()->mode() == MGetNextEntryForIterator::Map) {
+    emitGetNextEntryForIterator<MapIteratorObject, ValueMap>(lir);
+  } else {
+    MOZ_ASSERT(lir->mir()->mode() == MGetNextEntryForIterator::Set);
+    emitGetNextEntryForIterator<SetIteratorObject, ValueSet>(lir);
+  }
+}
+
+// The point of these is to inform Ion of where these values already are; they
+// don't normally generate code.  Still, visitWasmRegisterResult is
+// per-platform.
+void CodeGenerator::visitWasmRegisterPairResult(LWasmRegisterPairResult* lir) {}
+void CodeGenerator::visitWasmStackResult(LWasmStackResult* lir) {}
+void CodeGenerator::visitWasmStackResult64(LWasmStackResult64* lir) {}
+
+void CodeGenerator::visitWasmStackResultArea(LWasmStackResultArea* lir) {
+  LAllocation* output = lir->getDef(0)->output();
+  MOZ_ASSERT(output->isStackArea());
+  bool tempInit = false;
+  for (auto iter = output->toStackArea()->results(); iter; iter.next()) {
+    // Zero out ref stack results.
+    if (iter.isGcPointer()) {
+      Register temp = ToRegister(lir->temp());
+      if (!tempInit) {
+        masm.xorPtr(temp, temp);
+        tempInit = true;
+      }
+      masm.storePtr(temp, ToAddress(iter.alloc()));
+    }
+  }
+}
+
+void CodeGenerator::visitWasmCall(LWasmCall* lir) {
+  MWasmCall* mir = lir->mir();
+  bool needsBoundsCheck = lir->needsBoundsCheck();
+
+  MOZ_ASSERT((sizeof(wasm::Frame) + masm.framePushed()) % WasmStackAlignment ==
+             0);
+  static_assert(
+      WasmStackAlignment >= ABIStackAlignment &&
+          WasmStackAlignment % ABIStackAlignment == 0,
+      "The wasm stack alignment should subsume the ABI-required alignment");
+
+#ifdef DEBUG
+  Label ok;
+  masm.branchTestStackPtr(Assembler::Zero, Imm32(WasmStackAlignment - 1), &ok);
+  masm.breakpoint();
+  masm.bind(&ok);
+#endif
+
+  // LWasmCallBase::isCallPreserved() assumes that all MWasmCalls preserve the
+  // TLS and pinned regs. The only case where where we don't have to reload
+  // the TLS and pinned regs is when the callee preserves them.
+  bool reloadRegs = true;
+  bool switchRealm = true;
+
+  const wasm::CallSiteDesc& desc = mir->desc();
+  const wasm::CalleeDesc& callee = mir->callee();
+  switch (callee.which()) {
+    case wasm::CalleeDesc::Func:
+      masm.call(desc, callee.funcIndex());
+      reloadRegs = false;
+      switchRealm = false;
+      break;
+    case wasm::CalleeDesc::Import:
+      masm.wasmCallImport(desc, callee);
+      break;
+    case wasm::CalleeDesc::AsmJSTable:
+    case wasm::CalleeDesc::WasmTable:
+      masm.wasmCallIndirect(desc, callee, needsBoundsCheck);
+      reloadRegs = switchRealm = callee.which() == wasm::CalleeDesc::WasmTable;
+      break;
+    case wasm::CalleeDesc::Builtin:
+      masm.call(desc, callee.builtin());
+      reloadRegs = false;
+      switchRealm = false;
+      break;
+    case wasm::CalleeDesc::BuiltinInstanceMethod:
+      masm.wasmCallBuiltinInstanceMethod(desc, mir->instanceArg(),
+                                         callee.builtin(),
+                                         mir->builtinMethodFailureMode());
+      switchRealm = false;
+      break;
+  }
+
+  // Note the assembler offset for the associated LSafePoint.
+  markSafepointAt(masm.currentOffset(), lir);
+
+  // Now that all the outbound in-memory args are on the stack, note the
+  // required lower boundary point of the associated StackMap.
+  lir->safepoint()->setFramePushedAtStackMapBase(
+      masm.framePushed() - mir->stackArgAreaSizeUnaligned());
+  MOZ_ASSERT(!lir->safepoint()->isWasmTrap());
+
+  if (reloadRegs) {
+    masm.loadPtr(Address(masm.getStackPointer(), WasmCallerTLSOffsetBeforeCall),
+                 WasmTlsReg);
+    masm.loadWasmPinnedRegsFromTls();
+    if (switchRealm) {
+      masm.switchToWasmTlsRealm(ABINonArgReturnReg0, ABINonArgReturnReg1);
+    }
+  } else {
+    MOZ_ASSERT(!switchRealm);
+  }
+}
+
+void CodeGenerator::visitWasmLoadSlot(LWasmLoadSlot* ins) {
+  MIRType type = ins->type();
+  Register container = ToRegister(ins->containerRef());
+  Address addr(container, ins->offset());
+  AnyRegister dst = ToAnyRegister(ins->output());
+
+  switch (type) {
+    case MIRType::Int32:
+      masm.load32(addr, dst.gpr());
+      break;
+    case MIRType::Float32:
+      masm.loadFloat32(addr, dst.fpu());
+      break;
+    case MIRType::Double:
+      masm.loadDouble(addr, dst.fpu());
+      break;
+    case MIRType::Pointer:
+    case MIRType::RefOrNull:
+      masm.loadPtr(addr, dst.gpr());
+      break;
+#ifdef ENABLE_WASM_SIMD
+    case MIRType::Simd128:
+      masm.loadUnalignedSimd128(addr, dst.fpu());
+      break;
+#endif
+    default:
+      MOZ_CRASH("unexpected type in LoadPrimitiveValue");
+  }
+}
+
+void CodeGenerator::visitWasmStoreSlot(LWasmStoreSlot* ins) {
+  MIRType type = ins->type();
+  Register container = ToRegister(ins->containerRef());
+  Address addr(container, ins->offset());
+  AnyRegister src = ToAnyRegister(ins->value());
+
+  switch (type) {
+    case MIRType::Int32:
+      masm.store32(src.gpr(), addr);
+      break;
+    case MIRType::Float32:
+      masm.storeFloat32(src.fpu(), addr);
+      break;
+    case MIRType::Double:
+      masm.storeDouble(src.fpu(), addr);
+      break;
+    case MIRType::Pointer:
+      // This could be correct, but it would be a new usage, so check carefully.
+      MOZ_CRASH("Unexpected type in visitWasmStoreSlot.");
+    case MIRType::RefOrNull:
+      MOZ_CRASH("Bad type in visitWasmStoreSlot. Use LWasmStoreRef.");
+#ifdef ENABLE_WASM_SIMD
+    case MIRType::Simd128:
+      masm.storeUnalignedSimd128(src.fpu(), addr);
+      break;
+#endif
+    default:
+      MOZ_CRASH("unexpected type in StorePrimitiveValue");
+  }
+}
+
+void CodeGenerator::visitWasmDerivedPointer(LWasmDerivedPointer* ins) {
+  masm.movePtr(ToRegister(ins->base()), ToRegister(ins->output()));
+  masm.addPtr(Imm32(int32_t(ins->offset())), ToRegister(ins->output()));
+}
+
+void CodeGenerator::visitWasmStoreRef(LWasmStoreRef* ins) {
+  Register tls = ToRegister(ins->tls());
+  Register valueAddr = ToRegister(ins->valueAddr());
+  Register value = ToRegister(ins->value());
+  Register temp = ToRegister(ins->temp());
+
+  Label skipPreBarrier;
+  wasm::EmitWasmPreBarrierGuard(masm, tls, temp, valueAddr, &skipPreBarrier);
+  wasm::EmitWasmPreBarrierCall(masm, tls, temp, valueAddr);
+  masm.bind(&skipPreBarrier);
+
+  masm.storePtr(value, Address(valueAddr, 0));
+  // The postbarrier is handled separately.
+}
+
+void CodeGenerator::visitWasmLoadSlotI64(LWasmLoadSlotI64* ins) {
+  Register container = ToRegister(ins->containerRef());
+  Address addr(container, ins->offset());
+  Register64 output = ToOutRegister64(ins);
+  masm.load64(addr, output);
+}
+
+void CodeGenerator::visitWasmStoreSlotI64(LWasmStoreSlotI64* ins) {
+  Register container = ToRegister(ins->containerRef());
+  Address addr(container, ins->offset());
+  Register64 value = ToRegister64(ins->value());
+  masm.store64(value, addr);
+}
+
+void CodeGenerator::visitArrayBufferByteLengthInt32(
+    LArrayBufferByteLengthInt32* lir) {
+  Register obj = ToRegister(lir->object());
+  Register out = ToRegister(lir->output());
+  masm.loadArrayBufferByteLengthInt32(obj, out);
+}
+
+void CodeGenerator::visitArrayBufferViewLength(LArrayBufferViewLength* lir) {
+  Register obj = ToRegister(lir->object());
+  Register out = ToRegister(lir->output());
+  masm.loadArrayBufferViewLengthInt32(obj, out);
+}
+
+void CodeGenerator::visitArrayBufferViewByteOffset(
+    LArrayBufferViewByteOffset* lir) {
+  Register obj = ToRegister(lir->object());
+  Register out = ToRegister(lir->output());
+  masm.loadArrayBufferViewByteOffsetInt32(obj, out);
+}
+
+void CodeGenerator::visitArrayBufferViewElements(
+    LArrayBufferViewElements* lir) {
+  Register obj = ToRegister(lir->object());
+  Register out = ToRegister(lir->output());
+  masm.loadPtr(Address(obj, ArrayBufferViewObject::dataOffset()), out);
+}
+
+void CodeGenerator::visitTypedArrayElementShift(LTypedArrayElementShift* lir) {
+  Register obj = ToRegister(lir->object());
+  Register out = ToRegister(lir->output());
+
+  masm.typedArrayElementShift(obj, out);
+}
+
+class OutOfLineTypedArrayIndexToInt32
+    : public OutOfLineCodeBase<CodeGenerator> {
+  LTypedArrayIndexToInt32* lir_;
+
+ public:
+  explicit OutOfLineTypedArrayIndexToInt32(LTypedArrayIndexToInt32* lir)
+      : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineTypedArrayIndexToInt32(this);
+  }
+  LTypedArrayIndexToInt32* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitTypedArrayIndexToInt32(LTypedArrayIndexToInt32* lir) {
+  FloatRegister index = ToFloatRegister(lir->index());
+  Register output = ToRegister(lir->output());
+
+  auto* ool = new (alloc()) OutOfLineTypedArrayIndexToInt32(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  MOZ_ASSERT(TypedArrayObject::maxByteLength() <= INT32_MAX,
+             "Double exceeding Int32 range can't be in-bounds array access");
+
+  masm.convertDoubleToInt32(index, output, ool->entry(), false);
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineTypedArrayIndexToInt32(
+    OutOfLineTypedArrayIndexToInt32* ool) {
+  // Substitute the invalid index with an arbitrary out-of-bounds index.
+  masm.move32(Imm32(-1), ToRegister(ool->lir()->output()));
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitStringLength(LStringLength* lir) {
+  Register input = ToRegister(lir->string());
+  Register output = ToRegister(lir->output());
+
+  masm.loadStringLength(input, output);
+}
+
+void CodeGenerator::visitMinMaxI(LMinMaxI* ins) {
+  Register first = ToRegister(ins->first());
+  Register output = ToRegister(ins->output());
+
+  MOZ_ASSERT(first == output);
+
+  Assembler::Condition cond =
+      ins->mir()->isMax() ? Assembler::GreaterThan : Assembler::LessThan;
+
+  if (ins->second()->isConstant()) {
+    Label done;
+    masm.branch32(cond, first, Imm32(ToInt32(ins->second())), &done);
+    masm.move32(Imm32(ToInt32(ins->second())), output);
+    masm.bind(&done);
+  } else {
+    Register second = ToRegister(ins->second());
+    masm.cmp32Move32(cond, second, first, second, output);
+  }
+}
+
+void CodeGenerator::visitAbsI(LAbsI* ins) {
+  Register input = ToRegister(ins->input());
+  MOZ_ASSERT(input == ToRegister(ins->output()));
+
+  Label positive;
+  masm.branchTest32(Assembler::NotSigned, input, input, &positive);
+  if (ins->mir()->fallible()) {
+    Label bail;
+    masm.branchNeg32(Assembler::Overflow, input, &bail);
+    bailoutFrom(&bail, ins->snapshot());
+  } else {
+    masm.neg32(input);
+  }
+  masm.bind(&positive);
+}
+
+void CodeGenerator::visitAbsD(LAbsD* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  MOZ_ASSERT(input == ToFloatRegister(ins->output()));
+
+  masm.absDouble(input, input);
+}
+
+void CodeGenerator::visitAbsF(LAbsF* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  MOZ_ASSERT(input == ToFloatRegister(ins->output()));
+
+  masm.absFloat32(input, input);
+}
+
+void CodeGenerator::visitPowII(LPowII* ins) {
+  Register value = ToRegister(ins->value());
+  Register power = ToRegister(ins->power());
+  Register output = ToRegister(ins->output());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+
+  Label bailout;
+  masm.pow32(value, power, output, temp1, temp2, &bailout);
+  bailoutFrom(&bailout, ins->snapshot());
+}
+
+void CodeGenerator::visitPowI(LPowI* ins) {
+  FloatRegister value = ToFloatRegister(ins->value());
+  Register power = ToRegister(ins->power());
+  Register temp = ToRegister(ins->temp());
+
+  MOZ_ASSERT(power != temp);
+
+  using Fn = double (*)(double x, int32_t y);
+  masm.setupUnalignedABICall(temp);
+  masm.passABIArg(value, MoveOp::DOUBLE);
+  masm.passABIArg(power);
+
+  masm.callWithABI<Fn, js::powi>(MoveOp::DOUBLE);
+  MOZ_ASSERT(ToFloatRegister(ins->output()) == ReturnDoubleReg);
+}
+
+void CodeGenerator::visitPowD(LPowD* ins) {
+  FloatRegister value = ToFloatRegister(ins->value());
+  FloatRegister power = ToFloatRegister(ins->power());
+  Register temp = ToRegister(ins->temp());
+
+  using Fn = double (*)(double x, double y);
+  masm.setupUnalignedABICall(temp);
+  masm.passABIArg(value, MoveOp::DOUBLE);
+  masm.passABIArg(power, MoveOp::DOUBLE);
+  masm.callWithABI<Fn, ecmaPow>(MoveOp::DOUBLE);
+
+  MOZ_ASSERT(ToFloatRegister(ins->output()) == ReturnDoubleReg);
+}
+
+void CodeGenerator::visitPowOfTwoI(LPowOfTwoI* ins) {
+  Register power = ToRegister(ins->power());
+  Register output = ToRegister(ins->output());
+
+  uint32_t base = ins->base();
+  MOZ_ASSERT(mozilla::IsPowerOfTwo(base));
+
+  uint32_t n = mozilla::FloorLog2(base);
+  MOZ_ASSERT(n != 0);
+
+  // Hacker's Delight, 2nd edition, theorem D2.
+  auto ceilingDiv = [](uint32_t x, uint32_t y) { return (x + y - 1) / y; };
+
+  // Take bailout if |power| is greater-or-equals |log_y(2^31)| or is negative.
+  // |2^(n*y) < 2^31| must hold, hence |n*y < 31| resp. |y < 31/n|.
+  //
+  // Note: it's important for this condition to match the code in CacheIR.cpp
+  // (CanAttachInt32Pow) to prevent failure loops.
+  bailoutCmp32(Assembler::AboveOrEqual, power, Imm32(ceilingDiv(31, n)),
+               ins->snapshot());
+
+  // Compute (2^n)^y as 2^(n*y) using repeated shifts. We could directly scale
+  // |power| and perform a single shift, but due to the lack of necessary
+  // MacroAssembler functionality, like multiplying a register with an
+  // immediate, we restrict the number of generated shift instructions when
+  // lowering this operation.
+  masm.move32(Imm32(1), output);
+  do {
+    masm.lshift32(power, output);
+    n--;
+  } while (n > 0);
+}
+
+void CodeGenerator::visitSqrtD(LSqrtD* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  FloatRegister output = ToFloatRegister(ins->output());
+  masm.sqrtDouble(input, output);
+}
+
+void CodeGenerator::visitSqrtF(LSqrtF* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  FloatRegister output = ToFloatRegister(ins->output());
+  masm.sqrtFloat32(input, output);
+}
+
+void CodeGenerator::visitSignI(LSignI* ins) {
+  Register input = ToRegister(ins->input());
+  Register output = ToRegister(ins->output());
+  masm.signInt32(input, output);
+}
+
+void CodeGenerator::visitSignD(LSignD* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  FloatRegister output = ToFloatRegister(ins->output());
+  masm.signDouble(input, output);
+}
+
+void CodeGenerator::visitSignDI(LSignDI* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  FloatRegister temp = ToFloatRegister(ins->temp());
+  Register output = ToRegister(ins->output());
+
+  Label bail;
+  masm.signDoubleToInt32(input, output, temp, &bail);
+  bailoutFrom(&bail, ins->snapshot());
+}
+
+void CodeGenerator::visitMathFunctionD(LMathFunctionD* ins) {
+  Register temp = ToRegister(ins->temp());
+  FloatRegister input = ToFloatRegister(ins->input());
+  MOZ_ASSERT(ToFloatRegister(ins->output()) == ReturnDoubleReg);
+
+  UnaryMathFunction fun = ins->mir()->function();
+  UnaryMathFunctionType funPtr = GetUnaryMathFunctionPtr(fun);
+
+  masm.setupUnalignedABICall(temp);
+
+  masm.passABIArg(input, MoveOp::DOUBLE);
+  masm.callWithABI(DynamicFunction<UnaryMathFunctionType>(funPtr),
+                   MoveOp::DOUBLE);
+}
+
+void CodeGenerator::visitMathFunctionF(LMathFunctionF* ins) {
+  Register temp = ToRegister(ins->temp());
+  FloatRegister input = ToFloatRegister(ins->input());
+  MOZ_ASSERT(ToFloatRegister(ins->output()) == ReturnFloat32Reg);
+
+  masm.setupUnalignedABICall(temp);
+  masm.passABIArg(input, MoveOp::FLOAT32);
+
+  using Fn = float (*)(float x);
+  Fn funptr = nullptr;
+  CheckUnsafeCallWithABI check = CheckUnsafeCallWithABI::Check;
+  switch (ins->mir()->function()) {
+    case UnaryMathFunction::Floor:
+      funptr = floorf;
+      check = CheckUnsafeCallWithABI::DontCheckOther;
+      break;
+    case UnaryMathFunction::Round:
+      funptr = math_roundf_impl;
+      break;
+    case UnaryMathFunction::Trunc:
+      funptr = math_truncf_impl;
+      break;
+    case UnaryMathFunction::Ceil:
+      funptr = ceilf;
+      check = CheckUnsafeCallWithABI::DontCheckOther;
+      break;
+    default:
+      MOZ_CRASH("Unknown or unsupported float32 math function");
+  }
+
+  masm.callWithABI(DynamicFunction<Fn>(funptr), MoveOp::FLOAT32, check);
+}
+
+void CodeGenerator::visitModD(LModD* ins) {
+  MOZ_ASSERT(!gen->compilingWasm());
+
+  FloatRegister lhs = ToFloatRegister(ins->lhs());
+  FloatRegister rhs = ToFloatRegister(ins->rhs());
+
+  MOZ_ASSERT(ToFloatRegister(ins->output()) == ReturnDoubleReg);
+  MOZ_ASSERT(!ins->temp()->isBogusTemp());
+
+  using Fn = double (*)(double a, double b);
+  masm.setupUnalignedABICall(ToRegister(ins->temp()));
+  masm.passABIArg(lhs, MoveOp::DOUBLE);
+  masm.passABIArg(rhs, MoveOp::DOUBLE);
+  masm.callWithABI<Fn, NumberMod>(MoveOp::DOUBLE);
+}
+
+void CodeGenerator::visitModPowTwoD(LModPowTwoD* ins) {
+  FloatRegister lhs = ToFloatRegister(ins->lhs());
+  uint32_t divisor = ins->divisor();
+  MOZ_ASSERT(mozilla::IsPowerOfTwo(divisor));
+
+  FloatRegister output = ToFloatRegister(ins->output());
+
+  // Compute |n % d| using |copysign(n - (d * trunc(n / d)), n)|.
+  //
+  // This doesn't work if |d| isn't a power of two, because we may lose too much
+  // precision. For example |Number.MAX_VALUE % 3 == 2|, but
+  // |3 * trunc(Number.MAX_VALUE / 3) == Infinity|.
+
+  Label done;
+  {
+    ScratchDoubleScope scratch(masm);
+
+    // Subnormals can lead to performance degradation, which can make calling
+    // |fmod| faster than this inline implementation. Work around this issue by
+    // directly returning the input for any value in the interval ]-1, +1[.
+    Label notSubnormal;
+    masm.loadConstantDouble(1.0, scratch);
+    masm.loadConstantDouble(-1.0, output);
+    masm.branchDouble(Assembler::DoubleGreaterThanOrEqual, lhs, scratch,
+                      &notSubnormal);
+    masm.branchDouble(Assembler::DoubleLessThanOrEqual, lhs, output,
+                      &notSubnormal);
+
+    masm.moveDouble(lhs, output);
+    masm.jump(&done);
+
+    masm.bind(&notSubnormal);
+
+    if (divisor == 1) {
+      // The pattern |n % 1 == 0| is used to detect integer numbers. We can skip
+      // the multiplication by one in this case.
+      masm.moveDouble(lhs, output);
+      masm.nearbyIntDouble(RoundingMode::TowardsZero, output, scratch);
+      masm.subDouble(scratch, output);
+    } else {
+      masm.loadConstantDouble(1.0 / double(divisor), scratch);
+      masm.loadConstantDouble(double(divisor), output);
+
+      masm.mulDouble(lhs, scratch);
+      masm.nearbyIntDouble(RoundingMode::TowardsZero, scratch, scratch);
+      masm.mulDouble(output, scratch);
+
+      masm.moveDouble(lhs, output);
+      masm.subDouble(scratch, output);
+    }
+  }
+
+  masm.copySignDouble(output, lhs, output);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitWasmBuiltinModD(LWasmBuiltinModD* ins) {
+  masm.Push(WasmTlsReg);
+  int32_t framePushedAfterTls = masm.framePushed();
+
+  FloatRegister lhs = ToFloatRegister(ins->lhs());
+  FloatRegister rhs = ToFloatRegister(ins->rhs());
+
+  MOZ_ASSERT(ToFloatRegister(ins->output()) == ReturnDoubleReg);
+
+  masm.setupWasmABICall();
+  masm.passABIArg(lhs, MoveOp::DOUBLE);
+  masm.passABIArg(rhs, MoveOp::DOUBLE);
+
+  int32_t tlsOffset = masm.framePushed() - framePushedAfterTls;
+  masm.callWithABI(ins->mir()->bytecodeOffset(), wasm::SymbolicAddress::ModD,
+                   mozilla::Some(tlsOffset), MoveOp::DOUBLE);
+
+  masm.Pop(WasmTlsReg);
+}
+
+void CodeGenerator::visitBigIntAdd(LBigIntAdd* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::add>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // 0n + x == x
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(rhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x + 0n == x
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  masm.branchAddPtr(Assembler::Overflow, temp2, temp1, ool->entry());
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntSub(LBigIntSub* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::sub>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // x - 0n == x
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigInt(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  masm.branchSubPtr(Assembler::Overflow, temp2, temp1, ool->entry());
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntMul(LBigIntMul* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::mul>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // 0n * x == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x * 0n == 0n
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(rhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  masm.branchMulPtr(Assembler::Overflow, temp2, temp1, ool->entry());
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntDiv(LBigIntDiv* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::div>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // x / 0 throws an error.
+  if (ins->mir()->canBeDivideByZero()) {
+    masm.branchIfBigIntIsZero(rhs, ool->entry());
+  }
+
+  // 0n / x == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  // |BigInt::div()| returns |lhs| for |lhs / 1n|, which means there's no
+  // allocation which might trigger a minor GC to free up nursery space. This
+  // requires us to apply the same optimization here, otherwise we'd end up with
+  // always entering the OOL call, because the nursery is never evicted.
+  Label notOne;
+  masm.branchPtr(Assembler::NotEqual, temp2, ImmWord(1), &notOne);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&notOne);
+
+  static constexpr auto DigitMin = std::numeric_limits<
+      mozilla::SignedStdintTypeForSize<sizeof(BigInt::Digit)>::Type>::min();
+
+  // Handle an integer overflow from INT{32,64}_MIN / -1.
+  Label notOverflow;
+  masm.branchPtr(Assembler::NotEqual, temp1, ImmWord(DigitMin), &notOverflow);
+  masm.branchPtr(Assembler::Equal, temp2, ImmWord(-1), ool->entry());
+  masm.bind(&notOverflow);
+
+  emitBigIntDiv(ins, temp1, temp2, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntMod(LBigIntMod* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::mod>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // x % 0 throws an error.
+  if (ins->mir()->canBeDivideByZero()) {
+    masm.branchIfBigIntIsZero(rhs, ool->entry());
+  }
+
+  // 0n % x == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntAbsolute(lhs, temp1, ool->entry());
+  masm.loadBigIntAbsolute(rhs, temp2, ool->entry());
+
+  // Similar to the case for BigInt division, we must apply the same allocation
+  // optimizations as performed in |BigInt::mod()|.
+  Label notBelow;
+  masm.branchPtr(Assembler::AboveOrEqual, temp1, temp2, &notBelow);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&notBelow);
+
+  // Convert both digits to signed pointer-sized values.
+  masm.bigIntDigitToSignedPtr(lhs, temp1, ool->entry());
+  masm.bigIntDigitToSignedPtr(rhs, temp2, ool->entry());
+
+  static constexpr auto DigitMin = std::numeric_limits<
+      mozilla::SignedStdintTypeForSize<sizeof(BigInt::Digit)>::Type>::min();
+
+  // Handle an integer overflow from INT{32,64}_MIN / -1.
+  Label notOverflow;
+  masm.branchPtr(Assembler::NotEqual, temp1, ImmWord(DigitMin), &notOverflow);
+  masm.branchPtr(Assembler::NotEqual, temp2, ImmWord(-1), &notOverflow);
+  masm.movePtr(ImmWord(0), temp1);
+  masm.bind(&notOverflow);
+
+  emitBigIntMod(ins, temp1, temp2, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntPow(LBigIntPow* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::pow>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // x ** -y throws an error.
+  if (ins->mir()->canBeNegativeExponent()) {
+    masm.branchIfBigIntIsNegative(rhs, ool->entry());
+  }
+
+  Register dest = temp1;
+  Register base = temp2;
+  Register exponent = output;
+
+  Label done;
+  masm.movePtr(ImmWord(1), dest);  // p = 1
+
+  // 1n ** y == 1n
+  // -1n ** y == 1n when y is even
+  // -1n ** y == -1n when y is odd
+  Label lhsNotOne;
+  masm.branch32(Assembler::Above, Address(lhs, BigInt::offsetOfLength()),
+                Imm32(1), &lhsNotOne);
+  masm.loadFirstBigIntDigitOrZero(lhs, base);
+  masm.branchPtr(Assembler::NotEqual, base, Imm32(1), &lhsNotOne);
+  {
+    masm.loadFirstBigIntDigitOrZero(rhs, exponent);
+
+    Label lhsNonNegative;
+    masm.branchIfBigIntIsNonNegative(lhs, &lhsNonNegative);
+    masm.branchTestPtr(Assembler::Zero, exponent, Imm32(1), &done);
+    masm.bind(&lhsNonNegative);
+    masm.movePtr(lhs, output);
+    masm.jump(ool->rejoin());
+  }
+  masm.bind(&lhsNotOne);
+
+  // x ** 0n == 1n
+  masm.branchIfBigIntIsZero(rhs, &done);
+
+  // 0n ** y == 0n with y != 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  {
+    masm.movePtr(lhs, output);
+    masm.jump(ool->rejoin());
+  }
+  masm.bind(&lhsNonZero);
+
+  // Call into the VM when the exponent can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntAbsolute(rhs, exponent, ool->entry());
+
+  // x ** y with x > 1 and y >= DigitBits can't be pointer-sized.
+  masm.branchPtr(Assembler::AboveOrEqual, exponent, Imm32(BigInt::DigitBits),
+                 ool->entry());
+
+  // x ** 1n == x
+  Label rhsNotOne;
+  masm.branch32(Assembler::NotEqual, exponent, Imm32(1), &rhsNotOne);
+  {
+    masm.movePtr(lhs, output);
+    masm.jump(ool->rejoin());
+  }
+  masm.bind(&rhsNotOne);
+
+  // Call into the VM when the base operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, base, ool->entry());
+
+  // MacroAssembler::pow32() adjusted to work on pointer-sized registers.
+  {
+    // m = base
+    // n = exponent
+
+    Label start, loop;
+    masm.jump(&start);
+    masm.bind(&loop);
+
+    // m *= m
+    masm.branchMulPtr(Assembler::Overflow, base, base, ool->entry());
+
+    masm.bind(&start);
+
+    // if ((n & 1) != 0) p *= m
+    Label even;
+    masm.branchTest32(Assembler::Zero, exponent, Imm32(1), &even);
+    masm.branchMulPtr(Assembler::Overflow, base, dest, ool->entry());
+    masm.bind(&even);
+
+    // n >>= 1
+    // if (n == 0) return p
+    masm.branchRshift32(Assembler::NonZero, Imm32(1), exponent, &loop);
+  }
+
+  MOZ_ASSERT(temp1 == dest);
+
+  // Create and return the result.
+  masm.bind(&done);
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntBitAnd(LBigIntBitAnd* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::bitAnd>(ins, ArgList(lhs, rhs),
+                                            StoreRegisterTo(output));
+
+  // 0n & x == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x & 0n == 0n
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(rhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  masm.andPtr(temp2, temp1);
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntBitOr(LBigIntBitOr* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::bitOr>(ins, ArgList(lhs, rhs),
+                                           StoreRegisterTo(output));
+
+  // 0n | x == x
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(rhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x | 0n == x
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  masm.orPtr(temp2, temp1);
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntBitXor(LBigIntBitXor* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::bitXor>(ins, ArgList(lhs, rhs),
+                                            StoreRegisterTo(output));
+
+  // 0n ^ x == x
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(rhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x ^ 0n == x
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Call into the VM when either operand can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigIntNonZero(lhs, temp1, ool->entry());
+  masm.loadBigIntNonZero(rhs, temp2, ool->entry());
+
+  masm.xorPtr(temp2, temp1);
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntLsh(LBigIntLsh* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register temp3 = ToRegister(ins->temp3());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::lsh>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // 0n << x == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x << 0n == x
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Inline |BigInt::lsh| for the case when |lhs| contains a single digit.
+
+  Label rhsTooLarge;
+  masm.loadBigIntAbsolute(rhs, temp2, &rhsTooLarge);
+
+  // Call into the VM when the left-hand side operand can't be loaded into a
+  // pointer-sized register.
+  masm.loadBigIntAbsolute(lhs, temp1, ool->entry());
+
+  // Handle shifts exceeding |BigInt::DigitBits| first.
+  Label shift, create;
+  masm.branchPtr(Assembler::Below, temp2, Imm32(BigInt::DigitBits), &shift);
+  {
+    masm.bind(&rhsTooLarge);
+
+    // x << DigitBits with x != 0n always exceeds pointer-sized storage.
+    masm.branchIfBigIntIsNonNegative(rhs, ool->entry());
+
+    // x << -DigitBits == x >> DigitBits, which is either 0n or -1n.
+    masm.move32(Imm32(0), temp1);
+    masm.branchIfBigIntIsNonNegative(lhs, &create);
+    masm.move32(Imm32(1), temp1);
+    masm.jump(&create);
+  }
+  masm.bind(&shift);
+
+  Label nonNegative;
+  masm.branchIfBigIntIsNonNegative(rhs, &nonNegative);
+  {
+    masm.movePtr(temp1, temp3);
+
+    // |x << -y| is computed as |x >> y|.
+    masm.rshiftPtr(temp2, temp1);
+
+    // For negative numbers, round down if any bit was shifted out.
+    masm.branchIfBigIntIsNonNegative(lhs, &create);
+
+    // Compute |mask = (static_cast<Digit>(1) << shift) - 1|.
+    masm.movePtr(ImmWord(-1), output);
+    masm.lshiftPtr(temp2, output);
+    masm.notPtr(output);
+
+    // Add plus one when |(lhs.digit(0) & mask) != 0|.
+    masm.branchTestPtr(Assembler::Zero, output, temp3, &create);
+    masm.addPtr(ImmWord(1), temp1);
+    masm.jump(&create);
+  }
+  masm.bind(&nonNegative);
+  {
+    masm.movePtr(temp2, temp3);
+
+    // Compute |grow = lhs.digit(0) >> (DigitBits - shift)|.
+    masm.negPtr(temp2);
+    masm.addPtr(Imm32(BigInt::DigitBits), temp2);
+    masm.movePtr(temp1, output);
+    masm.rshiftPtr(temp2, output);
+
+    // Call into the VM when any bit will be shifted out.
+    masm.branchTestPtr(Assembler::NonZero, output, output, ool->entry());
+
+    masm.movePtr(temp3, temp2);
+    masm.lshiftPtr(temp2, temp1);
+  }
+  masm.bind(&create);
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigIntAbsolute(output, temp1);
+
+  // Set the sign bit when the left-hand side is negative.
+  masm.branchIfBigIntIsNonNegative(lhs, ool->rejoin());
+  masm.or32(Imm32(BigInt::signBitMask()),
+            Address(output, BigInt::offsetOfFlags()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntRsh(LBigIntRsh* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register rhs = ToRegister(ins->rhs());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register temp3 = ToRegister(ins->temp3());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::rsh>(ins, ArgList(lhs, rhs),
+                                         StoreRegisterTo(output));
+
+  // 0n >> x == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(lhs, &lhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // x >> 0n == x
+  Label rhsNonZero;
+  masm.branchIfBigIntIsNonZero(rhs, &rhsNonZero);
+  masm.movePtr(lhs, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&rhsNonZero);
+
+  // Inline |BigInt::rsh| for the case when |lhs| contains a single digit.
+
+  Label rhsTooLarge;
+  masm.loadBigIntAbsolute(rhs, temp2, &rhsTooLarge);
+
+  // Call into the VM when the left-hand side operand can't be loaded into a
+  // pointer-sized register.
+  masm.loadBigIntAbsolute(lhs, temp1, ool->entry());
+
+  // Handle shifts exceeding |BigInt::DigitBits| first.
+  Label shift, create;
+  masm.branchPtr(Assembler::Below, temp2, Imm32(BigInt::DigitBits), &shift);
+  {
+    masm.bind(&rhsTooLarge);
+
+    // x >> -DigitBits == x << DigitBits, which exceeds pointer-sized storage.
+    masm.branchIfBigIntIsNegative(rhs, ool->entry());
+
+    // x >> DigitBits is either 0n or -1n.
+    masm.move32(Imm32(0), temp1);
+    masm.branchIfBigIntIsNonNegative(lhs, &create);
+    masm.move32(Imm32(1), temp1);
+    masm.jump(&create);
+  }
+  masm.bind(&shift);
+
+  Label nonNegative;
+  masm.branchIfBigIntIsNonNegative(rhs, &nonNegative);
+  {
+    masm.movePtr(temp2, temp3);
+
+    // Compute |grow = lhs.digit(0) >> (DigitBits - shift)|.
+    masm.negPtr(temp2);
+    masm.addPtr(Imm32(BigInt::DigitBits), temp2);
+    masm.movePtr(temp1, output);
+    masm.rshiftPtr(temp2, output);
+
+    // Call into the VM when any bit will be shifted out.
+    masm.branchTestPtr(Assembler::NonZero, output, output, ool->entry());
+
+    // |x >> -y| is computed as |x << y|.
+    masm.movePtr(temp3, temp2);
+    masm.lshiftPtr(temp2, temp1);
+    masm.jump(&create);
+  }
+  masm.bind(&nonNegative);
+  {
+    masm.movePtr(temp1, temp3);
+
+    masm.rshiftPtr(temp2, temp1);
+
+    // For negative numbers, round down if any bit was shifted out.
+    masm.branchIfBigIntIsNonNegative(lhs, &create);
+
+    // Compute |mask = (static_cast<Digit>(1) << shift) - 1|.
+    masm.movePtr(ImmWord(-1), output);
+    masm.lshiftPtr(temp2, output);
+    masm.notPtr(output);
+
+    // Add plus one when |(lhs.digit(0) & mask) != 0|.
+    masm.branchTestPtr(Assembler::Zero, output, temp3, &create);
+    masm.addPtr(ImmWord(1), temp1);
+  }
+  masm.bind(&create);
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigIntAbsolute(output, temp1);
+
+  // Set the sign bit when the left-hand side is negative.
+  masm.branchIfBigIntIsNonNegative(lhs, ool->rejoin());
+  masm.or32(Imm32(BigInt::signBitMask()),
+            Address(output, BigInt::offsetOfFlags()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntIncrement(LBigIntIncrement* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt);
+  auto* ool =
+      oolCallVM<Fn, BigInt::inc>(ins, ArgList(input), StoreRegisterTo(output));
+
+  // Call into the VM when the input can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigInt(input, temp1, ool->entry());
+  masm.movePtr(ImmWord(1), temp2);
+
+  masm.branchAddPtr(Assembler::Overflow, temp2, temp1, ool->entry());
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntDecrement(LBigIntDecrement* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt);
+  auto* ool =
+      oolCallVM<Fn, BigInt::dec>(ins, ArgList(input), StoreRegisterTo(output));
+
+  // Call into the VM when the input can't be loaded into a pointer-sized
+  // register.
+  masm.loadBigInt(input, temp1, ool->entry());
+  masm.movePtr(ImmWord(1), temp2);
+
+  masm.branchSubPtr(Assembler::Overflow, temp2, temp1, ool->entry());
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigInt(output, temp1);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntNegate(LBigIntNegate* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp = ToRegister(ins->temp());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt);
+  auto* ool =
+      oolCallVM<Fn, BigInt::neg>(ins, ArgList(input), StoreRegisterTo(output));
+
+  // -0n == 0n
+  Label lhsNonZero;
+  masm.branchIfBigIntIsNonZero(input, &lhsNonZero);
+  masm.movePtr(input, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&lhsNonZero);
+
+  // Call into the VM when the input uses heap digits.
+  masm.copyBigIntWithInlineDigits(input, output, temp, ool->entry(),
+                                  bigIntsCanBeInNursery());
+
+  // Flip the sign bit.
+  masm.xor32(Imm32(BigInt::signBitMask()),
+             Address(output, BigInt::offsetOfFlags()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitBigIntBitNot(LBigIntBitNot* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp1 = ToRegister(ins->temp1());
+  Register temp2 = ToRegister(ins->temp2());
+  Register output = ToRegister(ins->output());
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt);
+  auto* ool = oolCallVM<Fn, BigInt::bitNot>(ins, ArgList(input),
+                                            StoreRegisterTo(output));
+
+  masm.loadBigIntAbsolute(input, temp1, ool->entry());
+
+  // This follows the C++ implementation because it let's us support the full
+  // range [-2^64, 2^64 - 1] on 64-bit resp. [-2^32, 2^32 - 1] on 32-bit.
+  Label nonNegative, done;
+  masm.branchIfBigIntIsNonNegative(input, &nonNegative);
+  {
+    // ~(-x) == ~(~(x-1)) == x-1
+    masm.subPtr(Imm32(1), temp1);
+    masm.jump(&done);
+  }
+  masm.bind(&nonNegative);
+  {
+    // ~x == -x-1 == -(x+1)
+    masm.movePtr(ImmWord(1), temp2);
+    masm.branchAddPtr(Assembler::CarrySet, temp2, temp1, ool->entry());
+  }
+  masm.bind(&done);
+
+  // Create and return the result.
+  masm.newGCBigInt(output, temp2, ool->entry(), bigIntsCanBeInNursery());
+  masm.initializeBigIntAbsolute(output, temp1);
+
+  // Set the sign bit when the input is positive.
+  masm.branchIfBigIntIsNegative(input, ool->rejoin());
+  masm.or32(Imm32(BigInt::signBitMask()),
+            Address(output, BigInt::offsetOfFlags()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitFloor(LFloor* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.floorDoubleToInt32(input, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitFloorF(LFloorF* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.floorFloat32ToInt32(input, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitCeil(LCeil* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.ceilDoubleToInt32(input, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitCeilF(LCeilF* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.ceilFloat32ToInt32(input, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitRound(LRound* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  FloatRegister temp = ToFloatRegister(lir->temp());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.roundDoubleToInt32(input, output, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitRoundF(LRoundF* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  FloatRegister temp = ToFloatRegister(lir->temp());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.roundFloat32ToInt32(input, output, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitTrunc(LTrunc* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.truncDoubleToInt32(input, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitTruncF(LTruncF* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  Label bail;
+  masm.truncFloat32ToInt32(input, output, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitCompareS(LCompareS* lir) {
+  JSOp op = lir->mir()->jsop();
+  Register left = ToRegister(lir->left());
+  Register right = ToRegister(lir->right());
+  Register output = ToRegister(lir->output());
+
+  OutOfLineCode* ool = nullptr;
+
+  using Fn = bool (*)(JSContext*, HandleString, HandleString, bool*);
+  if (op == JSOp::Eq || op == JSOp::StrictEq) {
+    ool = oolCallVM<Fn, jit::StringsEqual<EqualityKind::Equal>>(
+        lir, ArgList(left, right), StoreRegisterTo(output));
+  } else if (op == JSOp::Ne || op == JSOp::StrictNe) {
+    ool = oolCallVM<Fn, jit::StringsEqual<EqualityKind::NotEqual>>(
+        lir, ArgList(left, right), StoreRegisterTo(output));
+  } else if (op == JSOp::Lt) {
+    ool = oolCallVM<Fn, jit::StringsCompare<ComparisonKind::LessThan>>(
+        lir, ArgList(left, right), StoreRegisterTo(output));
+  } else if (op == JSOp::Le) {
+    // Push the operands in reverse order for JSOp::Le:
+    // - |left <= right| is implemented as |right >= left|.
+    ool =
+        oolCallVM<Fn, jit::StringsCompare<ComparisonKind::GreaterThanOrEqual>>(
+            lir, ArgList(right, left), StoreRegisterTo(output));
+  } else if (op == JSOp::Gt) {
+    // Push the operands in reverse order for JSOp::Gt:
+    // - |left > right| is implemented as |right < left|.
+    ool = oolCallVM<Fn, jit::StringsCompare<ComparisonKind::LessThan>>(
+        lir, ArgList(right, left), StoreRegisterTo(output));
+  } else {
+    MOZ_ASSERT(op == JSOp::Ge);
+    ool =
+        oolCallVM<Fn, jit::StringsCompare<ComparisonKind::GreaterThanOrEqual>>(
+            lir, ArgList(left, right), StoreRegisterTo(output));
+  }
+
+  masm.compareStrings(op, left, right, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCompareBigInt(LCompareBigInt* lir) {
+  JSOp op = lir->mir()->jsop();
+  Register left = ToRegister(lir->left());
+  Register right = ToRegister(lir->right());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  Register temp3 = ToRegister(lir->temp3());
+  Register output = ToRegister(lir->output());
+
+  Label notSame;
+  Label compareSign;
+  Label compareLength;
+  Label compareDigit;
+
+  Label* notSameSign;
+  Label* notSameLength;
+  Label* notSameDigit;
+  if (IsEqualityOp(op)) {
+    notSameSign = &notSame;
+    notSameLength = &notSame;
+    notSameDigit = &notSame;
+  } else {
+    notSameSign = &compareSign;
+    notSameLength = &compareLength;
+    notSameDigit = &compareDigit;
+  }
+
+  // Jump to |notSameSign| when the sign aren't the same.
+  masm.load32(Address(left, BigInt::offsetOfFlags()), temp1);
+  masm.xor32(Address(right, BigInt::offsetOfFlags()), temp1);
+  masm.branchTest32(Assembler::NonZero, temp1, Imm32(BigInt::signBitMask()),
+                    notSameSign);
+
+  // Jump to |notSameLength| when the digits length is different.
+  masm.load32(Address(right, BigInt::offsetOfLength()), temp1);
+  masm.branch32(Assembler::NotEqual, Address(left, BigInt::offsetOfLength()),
+                temp1, notSameLength);
+
+  // Both BigInts have the same sign and the same number of digits. Loop over
+  // each digit, starting with the left-most one, and break from the loop when
+  // the first non-matching digit was found.
+
+  masm.loadBigIntDigits(left, temp2);
+  masm.loadBigIntDigits(right, temp3);
+
+  static_assert(sizeof(BigInt::Digit) == sizeof(void*),
+                "BigInt::Digit is pointer sized");
+
+  masm.computeEffectiveAddress(BaseIndex(temp2, temp1, ScalePointer), temp2);
+  masm.computeEffectiveAddress(BaseIndex(temp3, temp1, ScalePointer), temp3);
+
+  Label start, loop;
+  masm.jump(&start);
+  masm.bind(&loop);
+
+  masm.subPtr(Imm32(sizeof(BigInt::Digit)), temp2);
+  masm.subPtr(Imm32(sizeof(BigInt::Digit)), temp3);
+
+  masm.loadPtr(Address(temp3, 0), output);
+  masm.branchPtr(Assembler::NotEqual, Address(temp2, 0), output, notSameDigit);
+
+  masm.bind(&start);
+  masm.branchSub32(Assembler::NotSigned, Imm32(1), temp1, &loop);
+
+  // No different digits were found, both BigInts are equal to each other.
+
+  Label done;
+  masm.move32(Imm32(op == JSOp::Eq || op == JSOp::StrictEq || op == JSOp::Le ||
+                    op == JSOp::Ge),
+              output);
+  masm.jump(&done);
+
+  if (IsEqualityOp(op)) {
+    masm.bind(&notSame);
+    masm.move32(Imm32(op == JSOp::Ne || op == JSOp::StrictNe), output);
+  } else {
+    Label invertWhenNegative;
+
+    // There are two cases when sign(left) != sign(right):
+    // 1. sign(left) = positive and sign(right) = negative,
+    // 2. or the dual case with reversed signs.
+    //
+    // For case 1, |left| <cmp> |right| is true for cmp=Gt or cmp=Ge and false
+    // for cmp=Lt or cmp=Le. Initialize the result for case 1 and handle case 2
+    // with |invertWhenNegative|.
+    masm.bind(&compareSign);
+    masm.move32(Imm32(op == JSOp::Gt || op == JSOp::Ge), output);
+    masm.jump(&invertWhenNegative);
+
+    // For sign(left) = sign(right) and len(digits(left)) != len(digits(right)),
+    // we have to consider the two cases:
+    // 1. len(digits(left)) < len(digits(right))
+    // 2. len(digits(left)) > len(digits(right))
+    //
+    // For |left| <cmp> |right| with cmp=Lt:
+    // Assume both BigInts are positive, then |left < right| is true for case 1
+    // and false for case 2. When both are negative, the result is reversed.
+    //
+    // The other comparison operators can be handled similarly.
+    //
+    // |temp1| holds the digits length of the right-hand side operand.
+    masm.bind(&compareLength);
+    masm.cmp32Set(JSOpToCondition(op, /* isSigned = */ false),
+                  Address(left, BigInt::offsetOfLength()), temp1, output);
+    masm.jump(&invertWhenNegative);
+
+    // Similar to the case above, compare the current digit to determine the
+    // overall comparison result.
+    //
+    // |temp2| points to the current digit of the left-hand side operand.
+    // |output| holds the current digit of the right-hand side operand.
+    masm.bind(&compareDigit);
+    masm.cmpPtrSet(JSOpToCondition(op, /* isSigned = */ false),
+                   Address(temp2, 0), output, output);
+
+    Label nonNegative;
+    masm.bind(&invertWhenNegative);
+    masm.branchIfBigIntIsNonNegative(left, &nonNegative);
+    masm.xor32(Imm32(1), output);
+    masm.bind(&nonNegative);
+  }
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitCompareBigIntInt32(LCompareBigIntInt32* lir) {
+  JSOp op = lir->mir()->jsop();
+  Register left = ToRegister(lir->left());
+  Register right = ToRegister(lir->right());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  Register output = ToRegister(lir->output());
+
+  Label ifTrue, ifFalse;
+  masm.compareBigIntAndInt32(op, left, right, temp1, temp2, &ifTrue, &ifFalse);
+
+  Label done;
+  masm.bind(&ifFalse);
+  masm.move32(Imm32(0), output);
+  masm.jump(&done);
+  masm.bind(&ifTrue);
+  masm.move32(Imm32(1), output);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitCompareBigIntDouble(LCompareBigIntDouble* lir) {
+  JSOp op = lir->mir()->jsop();
+  Register left = ToRegister(lir->left());
+  FloatRegister right = ToFloatRegister(lir->right());
+  Register temp = ToRegister(lir->temp());
+  Register output = ToRegister(lir->output());
+
+  masm.setupUnalignedABICall(temp);
+
+  // Push the operands in reverse order for JSOp::Le and JSOp::Gt:
+  // - |left <= right| is implemented as |right >= left|.
+  // - |left > right| is implemented as |right < left|.
+  if (op == JSOp::Le || op == JSOp::Gt) {
+    masm.passABIArg(right, MoveOp::DOUBLE);
+    masm.passABIArg(left);
+  } else {
+    masm.passABIArg(left);
+    masm.passABIArg(right, MoveOp::DOUBLE);
+  }
+
+  using FnBigIntNumber = bool (*)(BigInt*, double);
+  using FnNumberBigInt = bool (*)(double, BigInt*);
+  switch (op) {
+    case JSOp::Eq: {
+      masm.callWithABI<FnBigIntNumber,
+                       jit::BigIntNumberEqual<EqualityKind::Equal>>();
+      break;
+    }
+    case JSOp::Ne: {
+      masm.callWithABI<FnBigIntNumber,
+                       jit::BigIntNumberEqual<EqualityKind::NotEqual>>();
+      break;
+    }
+    case JSOp::Lt: {
+      masm.callWithABI<FnBigIntNumber,
+                       jit::BigIntNumberCompare<ComparisonKind::LessThan>>();
+      break;
+    }
+    case JSOp::Gt: {
+      masm.callWithABI<FnNumberBigInt,
+                       jit::NumberBigIntCompare<ComparisonKind::LessThan>>();
+      break;
+    }
+    case JSOp::Le: {
+      masm.callWithABI<
+          FnNumberBigInt,
+          jit::NumberBigIntCompare<ComparisonKind::GreaterThanOrEqual>>();
+      break;
+    }
+    case JSOp::Ge: {
+      masm.callWithABI<
+          FnBigIntNumber,
+          jit::BigIntNumberCompare<ComparisonKind::GreaterThanOrEqual>>();
+      break;
+    }
+    default:
+      MOZ_CRASH("unhandled op");
+  }
+
+  masm.storeCallBoolResult(output);
+}
+
+void CodeGenerator::visitCompareBigIntString(LCompareBigIntString* lir) {
+  JSOp op = lir->mir()->jsop();
+  Register left = ToRegister(lir->left());
+  Register right = ToRegister(lir->right());
+
+  // Push the operands in reverse order for JSOp::Le and JSOp::Gt:
+  // - |left <= right| is implemented as |right >= left|.
+  // - |left > right| is implemented as |right < left|.
+  if (op == JSOp::Le || op == JSOp::Gt) {
+    pushArg(left);
+    pushArg(right);
+  } else {
+    pushArg(right);
+    pushArg(left);
+  }
+
+  using FnBigIntString =
+      bool (*)(JSContext*, HandleBigInt, HandleString, bool*);
+  using FnStringBigInt =
+      bool (*)(JSContext*, HandleString, HandleBigInt, bool*);
+
+  switch (op) {
+    case JSOp::Eq: {
+      constexpr auto Equal = EqualityKind::Equal;
+      callVM<FnBigIntString, BigIntStringEqual<Equal>>(lir);
+      break;
+    }
+    case JSOp::Ne: {
+      constexpr auto NotEqual = EqualityKind::NotEqual;
+      callVM<FnBigIntString, BigIntStringEqual<NotEqual>>(lir);
+      break;
+    }
+    case JSOp::Lt: {
+      constexpr auto LessThan = ComparisonKind::LessThan;
+      callVM<FnBigIntString, BigIntStringCompare<LessThan>>(lir);
+      break;
+    }
+    case JSOp::Gt: {
+      constexpr auto LessThan = ComparisonKind::LessThan;
+      callVM<FnStringBigInt, StringBigIntCompare<LessThan>>(lir);
+      break;
+    }
+    case JSOp::Le: {
+      constexpr auto GreaterThanOrEqual = ComparisonKind::GreaterThanOrEqual;
+      callVM<FnStringBigInt, StringBigIntCompare<GreaterThanOrEqual>>(lir);
+      break;
+    }
+    case JSOp::Ge: {
+      constexpr auto GreaterThanOrEqual = ComparisonKind::GreaterThanOrEqual;
+      callVM<FnBigIntString, BigIntStringCompare<GreaterThanOrEqual>>(lir);
+      break;
+    }
+    default:
+      MOZ_CRASH("Unexpected compare op");
+  }
+}
+
+void CodeGenerator::visitIsNullOrLikeUndefinedV(LIsNullOrLikeUndefinedV* lir) {
+  JSOp op = lir->mir()->jsop();
+  MCompare::CompareType compareType = lir->mir()->compareType();
+  MOZ_ASSERT(compareType == MCompare::Compare_Undefined ||
+             compareType == MCompare::Compare_Null);
+
+  const ValueOperand value = ToValue(lir, LIsNullOrLikeUndefinedV::Value);
+  Register output = ToRegister(lir->output());
+
+  if (op == JSOp::Eq || op == JSOp::Ne) {
+    auto* ool = new (alloc()) OutOfLineTestObjectWithLabels();
+    addOutOfLineCode(ool, lir->mir());
+
+    Label* nullOrLikeUndefined = ool->label1();
+    Label* notNullOrLikeUndefined = ool->label2();
+
+    {
+      ScratchTagScope tag(masm, value);
+      masm.splitTagForTest(value, tag);
+
+      masm.branchTestNull(Assembler::Equal, tag, nullOrLikeUndefined);
+      masm.branchTestUndefined(Assembler::Equal, tag, nullOrLikeUndefined);
+
+      // Check whether it's a truthy object or a falsy object that emulates
+      // undefined.
+      masm.branchTestObject(Assembler::NotEqual, tag, notNullOrLikeUndefined);
+    }
+
+    Register objreg =
+        masm.extractObject(value, ToTempUnboxRegister(lir->tempToUnbox()));
+    branchTestObjectEmulatesUndefined(objreg, nullOrLikeUndefined,
+                                      notNullOrLikeUndefined,
+                                      ToRegister(lir->temp()), ool);
+    // fall through
+
+    Label done;
+
+    // It's not null or undefined, and if it's an object it doesn't
+    // emulate undefined, so it's not like undefined.
+    masm.move32(Imm32(op == JSOp::Ne), output);
+    masm.jump(&done);
+
+    masm.bind(nullOrLikeUndefined);
+    masm.move32(Imm32(op == JSOp::Eq), output);
+
+    // Both branches meet here.
+    masm.bind(&done);
+    return;
+  }
+
+  MOZ_ASSERT(op == JSOp::StrictEq || op == JSOp::StrictNe);
+
+  Assembler::Condition cond = JSOpToCondition(compareType, op);
+  if (compareType == MCompare::Compare_Null) {
+    masm.testNullSet(cond, value, output);
+  } else {
+    masm.testUndefinedSet(cond, value, output);
+  }
+}
+
+void CodeGenerator::visitIsNullOrLikeUndefinedAndBranchV(
+    LIsNullOrLikeUndefinedAndBranchV* lir) {
+  JSOp op = lir->cmpMir()->jsop();
+  MCompare::CompareType compareType = lir->cmpMir()->compareType();
+  MOZ_ASSERT(compareType == MCompare::Compare_Undefined ||
+             compareType == MCompare::Compare_Null);
+
+  const ValueOperand value =
+      ToValue(lir, LIsNullOrLikeUndefinedAndBranchV::Value);
+
+  if (op == JSOp::Eq || op == JSOp::Ne) {
+    MBasicBlock* ifTrue;
+    MBasicBlock* ifFalse;
+
+    if (op == JSOp::Eq) {
+      ifTrue = lir->ifTrue();
+      ifFalse = lir->ifFalse();
+    } else {
+      // Swap branches.
+      ifTrue = lir->ifFalse();
+      ifFalse = lir->ifTrue();
+      op = JSOp::Eq;
+    }
+
+    auto* ool = new (alloc()) OutOfLineTestObject();
+    addOutOfLineCode(ool, lir->cmpMir());
+
+    Label* ifTrueLabel = getJumpLabelForBranch(ifTrue);
+    Label* ifFalseLabel = getJumpLabelForBranch(ifFalse);
+
+    {
+      ScratchTagScope tag(masm, value);
+      masm.splitTagForTest(value, tag);
+
+      masm.branchTestNull(Assembler::Equal, tag, ifTrueLabel);
+      masm.branchTestUndefined(Assembler::Equal, tag, ifTrueLabel);
+
+      masm.branchTestObject(Assembler::NotEqual, tag, ifFalseLabel);
+    }
+
+    // Objects that emulate undefined are loosely equal to null/undefined.
+    Register objreg =
+        masm.extractObject(value, ToTempUnboxRegister(lir->tempToUnbox()));
+    Register scratch = ToRegister(lir->temp());
+    testObjectEmulatesUndefined(objreg, ifTrueLabel, ifFalseLabel, scratch,
+                                ool);
+    return;
+  }
+
+  MOZ_ASSERT(op == JSOp::StrictEq || op == JSOp::StrictNe);
+
+  Assembler::Condition cond = JSOpToCondition(compareType, op);
+  if (compareType == MCompare::Compare_Null) {
+    testNullEmitBranch(cond, value, lir->ifTrue(), lir->ifFalse());
+  } else {
+    testUndefinedEmitBranch(cond, value, lir->ifTrue(), lir->ifFalse());
+  }
+}
+
+void CodeGenerator::visitIsNullOrLikeUndefinedT(LIsNullOrLikeUndefinedT* lir) {
+  MOZ_ASSERT(lir->mir()->compareType() == MCompare::Compare_Undefined ||
+             lir->mir()->compareType() == MCompare::Compare_Null);
+  MOZ_ASSERT(lir->mir()->lhs()->type() == MIRType::Object);
+
+  JSOp op = lir->mir()->jsop();
+  MOZ_ASSERT(op == JSOp::Eq || op == JSOp::Ne,
+             "Strict equality should have been folded");
+
+  Register objreg = ToRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  auto* ool = new (alloc()) OutOfLineTestObjectWithLabels();
+  addOutOfLineCode(ool, lir->mir());
+
+  Label* emulatesUndefined = ool->label1();
+  Label* doesntEmulateUndefined = ool->label2();
+
+  branchTestObjectEmulatesUndefined(objreg, emulatesUndefined,
+                                    doesntEmulateUndefined, output, ool);
+
+  Label done;
+
+  masm.move32(Imm32(op == JSOp::Ne), output);
+  masm.jump(&done);
+
+  masm.bind(emulatesUndefined);
+  masm.move32(Imm32(op == JSOp::Eq), output);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitIsNullOrLikeUndefinedAndBranchT(
+    LIsNullOrLikeUndefinedAndBranchT* lir) {
+  DebugOnly<MCompare::CompareType> compareType = lir->cmpMir()->compareType();
+  MOZ_ASSERT(compareType == MCompare::Compare_Undefined ||
+             compareType == MCompare::Compare_Null);
+  MOZ_ASSERT(lir->cmpMir()->lhs()->type() == MIRType::Object);
+
+  JSOp op = lir->cmpMir()->jsop();
+  MOZ_ASSERT(op == JSOp::Eq || op == JSOp::Ne,
+             "Strict equality should have been folded");
+
+  MBasicBlock* ifTrue;
+  MBasicBlock* ifFalse;
+
+  if (op == JSOp::Eq || op == JSOp::StrictEq) {
+    ifTrue = lir->ifTrue();
+    ifFalse = lir->ifFalse();
+  } else {
+    // Swap branches.
+    ifTrue = lir->ifFalse();
+    ifFalse = lir->ifTrue();
+  }
+
+  Register input = ToRegister(lir->getOperand(0));
+
+  auto* ool = new (alloc()) OutOfLineTestObject();
+  addOutOfLineCode(ool, lir->cmpMir());
+
+  Label* ifTrueLabel = getJumpLabelForBranch(ifTrue);
+  Label* ifFalseLabel = getJumpLabelForBranch(ifFalse);
+
+  // Objects that emulate undefined are loosely equal to null/undefined.
+  Register scratch = ToRegister(lir->temp());
+  testObjectEmulatesUndefined(input, ifTrueLabel, ifFalseLabel, scratch, ool);
+}
+
+void CodeGenerator::visitSameValueD(LSameValueD* lir) {
+  FloatRegister left = ToFloatRegister(lir->left());
+  FloatRegister right = ToFloatRegister(lir->right());
+  FloatRegister temp = ToFloatRegister(lir->tempFloat());
+  Register output = ToRegister(lir->output());
+
+  masm.sameValueDouble(left, right, temp, output);
+}
+
+void CodeGenerator::emitConcat(LInstruction* lir, Register lhs, Register rhs,
+                               Register output) {
+  using Fn = JSString* (*)(JSContext*, HandleString, HandleString,
+                           js::gc::InitialHeap);
+  OutOfLineCode* ool = oolCallVM<Fn, ConcatStrings<CanGC>>(
+      lir, ArgList(lhs, rhs, static_cast<Imm32>(gc::DefaultHeap)),
+      StoreRegisterTo(output));
+
+  const JitRealm* jitRealm = gen->realm->jitRealm();
+  JitCode* stringConcatStub =
+      jitRealm->stringConcatStubNoBarrier(&realmStubsToReadBarrier_);
+  masm.call(stringConcatStub);
+  masm.branchTestPtr(Assembler::Zero, output, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitConcat(LConcat* lir) {
+  Register lhs = ToRegister(lir->lhs());
+  Register rhs = ToRegister(lir->rhs());
+
+  Register output = ToRegister(lir->output());
+
+  MOZ_ASSERT(lhs == CallTempReg0);
+  MOZ_ASSERT(rhs == CallTempReg1);
+  MOZ_ASSERT(ToRegister(lir->temp1()) == CallTempReg0);
+  MOZ_ASSERT(ToRegister(lir->temp2()) == CallTempReg1);
+  MOZ_ASSERT(ToRegister(lir->temp3()) == CallTempReg2);
+  MOZ_ASSERT(ToRegister(lir->temp4()) == CallTempReg3);
+  MOZ_ASSERT(ToRegister(lir->temp5()) == CallTempReg4);
+  MOZ_ASSERT(output == CallTempReg5);
+
+  emitConcat(lir, lhs, rhs, output);
+}
+
+static void CopyStringChars(MacroAssembler& masm, Register to, Register from,
+                            Register len, Register byteOpScratch,
+                            CharEncoding fromEncoding,
+                            CharEncoding toEncoding) {
+  // Copy |len| char16_t code units from |from| to |to|. Assumes len > 0
+  // (checked below in debug builds), and when done |to| must point to the
+  // next available char.
+
+#ifdef DEBUG
+  Label ok;
+  masm.branch32(Assembler::GreaterThan, len, Imm32(0), &ok);
+  masm.assumeUnreachable("Length should be greater than 0.");
+  masm.bind(&ok);
+#endif
+
+  MOZ_ASSERT_IF(toEncoding == CharEncoding::Latin1,
+                fromEncoding == CharEncoding::Latin1);
+
+  size_t fromWidth =
+      fromEncoding == CharEncoding::Latin1 ? sizeof(char) : sizeof(char16_t);
+  size_t toWidth =
+      toEncoding == CharEncoding::Latin1 ? sizeof(char) : sizeof(char16_t);
+
+  Label start;
+  masm.bind(&start);
+  masm.loadChar(Address(from, 0), byteOpScratch, fromEncoding);
+  masm.storeChar(byteOpScratch, Address(to, 0), toEncoding);
+  masm.addPtr(Imm32(fromWidth), from);
+  masm.addPtr(Imm32(toWidth), to);
+  masm.branchSub32(Assembler::NonZero, Imm32(1), len, &start);
+}
+
+static void CopyStringChars(MacroAssembler& masm, Register to, Register from,
+                            Register len, Register byteOpScratch,
+                            CharEncoding encoding) {
+  CopyStringChars(masm, to, from, len, byteOpScratch, encoding, encoding);
+}
+
+static void CopyStringCharsMaybeInflate(MacroAssembler& masm, Register input,
+                                        Register destChars, Register temp1,
+                                        Register temp2) {
+  // destChars is TwoByte and input is a Latin1 or TwoByte string, so we may
+  // have to inflate.
+
+  Label isLatin1, done;
+  masm.loadStringLength(input, temp1);
+  masm.branchLatin1String(input, &isLatin1);
+  {
+    masm.loadStringChars(input, temp2, CharEncoding::TwoByte);
+    masm.movePtr(temp2, input);
+    CopyStringChars(masm, destChars, input, temp1, temp2,
+                    CharEncoding::TwoByte);
+    masm.jump(&done);
+  }
+  masm.bind(&isLatin1);
+  {
+    masm.loadStringChars(input, temp2, CharEncoding::Latin1);
+    masm.movePtr(temp2, input);
+    CopyStringChars(masm, destChars, input, temp1, temp2, CharEncoding::Latin1,
+                    CharEncoding::TwoByte);
+  }
+  masm.bind(&done);
+}
+
+static void ConcatInlineString(MacroAssembler& masm, Register lhs, Register rhs,
+                               Register output, Register temp1, Register temp2,
+                               Register temp3, bool stringsCanBeInNursery,
+                               Label* failure, CharEncoding encoding) {
+  JitSpew(JitSpew_Codegen, "# Emitting ConcatInlineString (encoding=%s)",
+          (encoding == CharEncoding::Latin1 ? "Latin-1" : "Two-Byte"));
+
+  // State: result length in temp2.
+
+  // Ensure both strings are linear.
+  masm.branchIfRope(lhs, failure);
+  masm.branchIfRope(rhs, failure);
+
+  // Allocate a JSThinInlineString or JSFatInlineString.
+  size_t maxThinInlineLength;
+  if (encoding == CharEncoding::Latin1) {
+    maxThinInlineLength = JSThinInlineString::MAX_LENGTH_LATIN1;
+  } else {
+    maxThinInlineLength = JSThinInlineString::MAX_LENGTH_TWO_BYTE;
+  }
+
+  Label isFat, allocDone;
+  masm.branch32(Assembler::Above, temp2, Imm32(maxThinInlineLength), &isFat);
+  {
+    uint32_t flags = JSString::INIT_THIN_INLINE_FLAGS;
+    if (encoding == CharEncoding::Latin1) {
+      flags |= JSString::LATIN1_CHARS_BIT;
+    }
+    masm.newGCString(output, temp1, failure, stringsCanBeInNursery);
+    masm.store32(Imm32(flags), Address(output, JSString::offsetOfFlags()));
+    masm.jump(&allocDone);
+  }
+  masm.bind(&isFat);
+  {
+    uint32_t flags = JSString::INIT_FAT_INLINE_FLAGS;
+    if (encoding == CharEncoding::Latin1) {
+      flags |= JSString::LATIN1_CHARS_BIT;
+    }
+    masm.newGCFatInlineString(output, temp1, failure, stringsCanBeInNursery);
+    masm.store32(Imm32(flags), Address(output, JSString::offsetOfFlags()));
+  }
+  masm.bind(&allocDone);
+
+  // Store length.
+  masm.store32(temp2, Address(output, JSString::offsetOfLength()));
+
+  // Load chars pointer in temp2.
+  masm.loadInlineStringCharsForStore(output, temp2);
+
+  auto copyChars = [&](Register src) {
+    if (encoding == CharEncoding::TwoByte) {
+      CopyStringCharsMaybeInflate(masm, src, temp2, temp1, temp3);
+    } else {
+      masm.loadStringLength(src, temp3);
+      masm.loadStringChars(src, temp1, CharEncoding::Latin1);
+      masm.movePtr(temp1, src);
+      CopyStringChars(masm, temp2, src, temp3, temp1, CharEncoding::Latin1);
+    }
+  };
+
+  // Copy lhs chars. Note that this advances temp2 to point to the next
+  // char. This also clobbers the lhs register.
+  copyChars(lhs);
+
+  // Copy rhs chars. Clobbers the rhs register.
+  copyChars(rhs);
+
+  masm.ret();
+}
+
+void CodeGenerator::visitSubstr(LSubstr* lir) {
+  Register string = ToRegister(lir->string());
+  Register begin = ToRegister(lir->begin());
+  Register length = ToRegister(lir->length());
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+  Register temp3 = ToRegister(lir->temp3());
+
+  // On x86 there are not enough registers. In that case reuse the string
+  // register as temporary.
+  Register temp2 =
+      lir->temp2()->isBogusTemp() ? string : ToRegister(lir->temp2());
+
+  Address stringFlags(string, JSString::offsetOfFlags());
+
+  Label isLatin1, notInline, nonZero, isInlinedLatin1;
+
+  // For every edge case use the C++ variant.
+  // Note: we also use this upon allocation failure in newGCString and
+  // newGCFatInlineString. To squeeze out even more performance those failures
+  // can be handled by allocate in ool code and returning to jit code to fill
+  // in all data.
+  using Fn = JSString* (*)(JSContext * cx, HandleString str, int32_t begin,
+                           int32_t len);
+  OutOfLineCode* ool = oolCallVM<Fn, SubstringKernel>(
+      lir, ArgList(string, begin, length), StoreRegisterTo(output));
+  Label* slowPath = ool->entry();
+  Label* done = ool->rejoin();
+
+  // Zero length, return emptystring.
+  masm.branchTest32(Assembler::NonZero, length, length, &nonZero);
+  const JSAtomState& names = gen->runtime->names();
+  masm.movePtr(ImmGCPtr(names.empty), output);
+  masm.jump(done);
+
+  // Use slow path for ropes.
+  masm.bind(&nonZero);
+  masm.branchIfRope(string, slowPath);
+
+  // Handle inlined strings by creating a FatInlineString.
+  masm.branchTest32(Assembler::Zero, stringFlags,
+                    Imm32(JSString::INLINE_CHARS_BIT), &notInline);
+  masm.newGCFatInlineString(output, temp, slowPath, stringsCanBeInNursery());
+  masm.store32(length, Address(output, JSString::offsetOfLength()));
+
+  auto initializeFatInlineString = [&](CharEncoding encoding) {
+    uint32_t flags = JSString::INIT_FAT_INLINE_FLAGS;
+    if (encoding == CharEncoding::Latin1) {
+      flags |= JSString::LATIN1_CHARS_BIT;
+    }
+
+    masm.store32(Imm32(flags), Address(output, JSString::offsetOfFlags()));
+    masm.loadInlineStringChars(string, temp, encoding);
+    masm.addToCharPtr(temp, begin, encoding);
+    if (temp2 == string) {
+      masm.push(string);
+    }
+    masm.loadInlineStringCharsForStore(output, temp2);
+    CopyStringChars(masm, temp2, temp, length, temp3, encoding);
+    masm.loadStringLength(output, length);
+    if (temp2 == string) {
+      masm.pop(string);
+    }
+    masm.jump(done);
+  };
+
+  masm.branchLatin1String(string, &isInlinedLatin1);
+  { initializeFatInlineString(CharEncoding::TwoByte); }
+  masm.bind(&isInlinedLatin1);
+  { initializeFatInlineString(CharEncoding::Latin1); }
+
+  // Handle other cases with a DependentString.
+  masm.bind(&notInline);
+  masm.newGCString(output, temp, slowPath, gen->stringsCanBeInNursery());
+  masm.store32(length, Address(output, JSString::offsetOfLength()));
+  masm.storeDependentStringBase(string, output);
+
+  auto initializeDependentString = [&](CharEncoding encoding) {
+    uint32_t flags = JSString::INIT_DEPENDENT_FLAGS;
+    if (encoding == CharEncoding::Latin1) {
+      flags |= JSString::LATIN1_CHARS_BIT;
+    }
+
+    masm.store32(Imm32(flags), Address(output, JSString::offsetOfFlags()));
+    masm.loadNonInlineStringChars(string, temp, encoding);
+    masm.addToCharPtr(temp, begin, encoding);
+    masm.storeNonInlineStringChars(temp, output);
+    masm.jump(done);
+  };
+
+  masm.branchLatin1String(string, &isLatin1);
+  { initializeDependentString(CharEncoding::TwoByte); }
+  masm.bind(&isLatin1);
+  { initializeDependentString(CharEncoding::Latin1); }
+
+  masm.bind(done);
+}
+
+JitCode* JitRealm::generateStringConcatStub(JSContext* cx) {
+  JitSpew(JitSpew_Codegen, "# Emitting StringConcat stub");
+
+  StackMacroAssembler masm(cx);
+
+  Register lhs = CallTempReg0;
+  Register rhs = CallTempReg1;
+  Register temp1 = CallTempReg2;
+  Register temp2 = CallTempReg3;
+  Register temp3 = CallTempReg4;
+  Register output = CallTempReg5;
+
+  Label failure;
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+  // If lhs is empty, return rhs.
+  Label leftEmpty;
+  masm.loadStringLength(lhs, temp1);
+  masm.branchTest32(Assembler::Zero, temp1, temp1, &leftEmpty);
+
+  // If rhs is empty, return lhs.
+  Label rightEmpty;
+  masm.loadStringLength(rhs, temp2);
+  masm.branchTest32(Assembler::Zero, temp2, temp2, &rightEmpty);
+
+  masm.add32(temp1, temp2);
+
+  // Check if we can use a JSFatInlineString. The result is a Latin1 string if
+  // lhs and rhs are both Latin1, so we AND the flags.
+  Label isFatInlineTwoByte, isFatInlineLatin1;
+  masm.load32(Address(lhs, JSString::offsetOfFlags()), temp1);
+  masm.and32(Address(rhs, JSString::offsetOfFlags()), temp1);
+
+  Label isLatin1, notInline;
+  masm.branchTest32(Assembler::NonZero, temp1,
+                    Imm32(JSString::LATIN1_CHARS_BIT), &isLatin1);
+  {
+    masm.branch32(Assembler::BelowOrEqual, temp2,
+                  Imm32(JSFatInlineString::MAX_LENGTH_TWO_BYTE),
+                  &isFatInlineTwoByte);
+    masm.jump(&notInline);
+  }
+  masm.bind(&isLatin1);
+  {
+    masm.branch32(Assembler::BelowOrEqual, temp2,
+                  Imm32(JSFatInlineString::MAX_LENGTH_LATIN1),
+                  &isFatInlineLatin1);
+  }
+  masm.bind(&notInline);
+
+  // Keep AND'ed flags in temp1.
+
+  // Ensure result length <= JSString::MAX_LENGTH.
+  masm.branch32(Assembler::Above, temp2, Imm32(JSString::MAX_LENGTH), &failure);
+
+  // Allocate a new rope, guaranteed to be in the nursery if
+  // stringsCanBeInNursery. (As a result, no post barriers are needed below.)
+  masm.newGCString(output, temp3, &failure, stringsCanBeInNursery);
+
+  // Store rope length and flags. temp1 still holds the result of AND'ing the
+  // lhs and rhs flags, so we just have to clear the other flags to get our rope
+  // flags (Latin1 if both lhs and rhs are Latin1).
+  static_assert(JSString::INIT_ROPE_FLAGS == 0,
+                "Rope type flags must have no bits set");
+  masm.and32(Imm32(JSString::LATIN1_CHARS_BIT), temp1);
+  masm.store32(temp1, Address(output, JSString::offsetOfFlags()));
+  masm.store32(temp2, Address(output, JSString::offsetOfLength()));
+
+  // Store left and right nodes.
+  masm.storeRopeChildren(lhs, rhs, output);
+  masm.ret();
+
+  masm.bind(&leftEmpty);
+  masm.mov(rhs, output);
+  masm.ret();
+
+  masm.bind(&rightEmpty);
+  masm.mov(lhs, output);
+  masm.ret();
+
+  masm.bind(&isFatInlineTwoByte);
+  ConcatInlineString(masm, lhs, rhs, output, temp1, temp2, temp3,
+                     stringsCanBeInNursery, &failure, CharEncoding::TwoByte);
+
+  masm.bind(&isFatInlineLatin1);
+  ConcatInlineString(masm, lhs, rhs, output, temp1, temp2, temp3,
+                     stringsCanBeInNursery, &failure, CharEncoding::Latin1);
+
+  masm.pop(temp2);
+  masm.pop(temp1);
+
+  masm.bind(&failure);
+  masm.movePtr(ImmPtr(nullptr), output);
+  masm.ret();
+
+  Linker linker(masm);
+  JitCode* code = linker.newCode(cx, CodeKind::Other);
+
+#ifdef JS_ION_PERF
+  writePerfSpewerJitCodeProfile(code, "StringConcatStub");
+#endif
+#ifdef MOZ_VTUNE
+  vtune::MarkStub(code, "StringConcatStub");
+#endif
+
+  return code;
+}
+
+void JitRuntime::generateFreeStub(MacroAssembler& masm) {
+  const Register regSlots = CallTempReg0;
+
+  freeStubOffset_ = startTrampolineCode(masm);
+
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+  AllocatableRegisterSet regs(RegisterSet::Volatile());
+  regs.takeUnchecked(regSlots);
+  LiveRegisterSet save(regs.asLiveSet());
+  masm.PushRegsInMask(save);
+
+  const Register regTemp = regs.takeAnyGeneral();
+  MOZ_ASSERT(regTemp != regSlots);
+
+  using Fn = void (*)(void* p);
+  masm.setupUnalignedABICall(regTemp);
+  masm.passABIArg(regSlots);
+  masm.callWithABI<Fn, js_free>(MoveOp::GENERAL,
+                                CheckUnsafeCallWithABI::DontCheckOther);
+
+  masm.PopRegsInMask(save);
+
+  masm.ret();
+}
+
+void JitRuntime::generateLazyLinkStub(MacroAssembler& masm) {
+  lazyLinkStubOffset_ = startTrampolineCode(masm);
+
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::Volatile());
+  Register temp0 = regs.takeAny();
+  Register temp1 = regs.takeAny();
+  Register temp2 = regs.takeAny();
+
+  masm.loadJSContext(temp0);
+  masm.enterFakeExitFrame(temp0, temp2, ExitFrameType::LazyLink);
+  masm.moveStackPtrTo(temp1);
+
+  using Fn = uint8_t* (*)(JSContext * cx, LazyLinkExitFrameLayout * frame);
+  masm.setupUnalignedABICall(temp2);
+  masm.passABIArg(temp0);
+  masm.passABIArg(temp1);
+  masm.callWithABI<Fn, LazyLinkTopActivation>(
+      MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+  masm.leaveExitFrame();
+
+#ifdef JS_USE_LINK_REGISTER
+  // Restore the return address such that the emitPrologue function of the
+  // CodeGenerator can push it back on the stack with pushReturnAddress.
+  masm.popReturnAddress();
+#endif
+  masm.jump(ReturnReg);
+}
+
+void JitRuntime::generateInterpreterStub(MacroAssembler& masm) {
+  interpreterStubOffset_ = startTrampolineCode(masm);
+
+#ifdef JS_USE_LINK_REGISTER
+  masm.pushReturnAddress();
+#endif
+
+  AllocatableGeneralRegisterSet regs(GeneralRegisterSet::Volatile());
+  Register temp0 = regs.takeAny();
+  Register temp1 = regs.takeAny();
+  Register temp2 = regs.takeAny();
+
+  masm.loadJSContext(temp0);
+  masm.enterFakeExitFrame(temp0, temp2, ExitFrameType::InterpreterStub);
+  masm.moveStackPtrTo(temp1);
+
+  using Fn = bool (*)(JSContext * cx, InterpreterStubExitFrameLayout * frame);
+  masm.setupUnalignedABICall(temp2);
+  masm.passABIArg(temp0);
+  masm.passABIArg(temp1);
+  masm.callWithABI<Fn, InvokeFromInterpreterStub>(
+      MoveOp::GENERAL, CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+  masm.branchIfFalseBool(ReturnReg, masm.failureLabel());
+  masm.leaveExitFrame();
+
+  // InvokeFromInterpreterStub stores the return value in argv[0], where the
+  // caller stored |this|.
+  masm.loadValue(
+      Address(masm.getStackPointer(), JitFrameLayout::offsetOfThis()),
+      JSReturnOperand);
+  masm.ret();
+}
+
+void JitRuntime::generateDoubleToInt32ValueStub(MacroAssembler& masm) {
+  doubleToInt32ValueStubOffset_ = startTrampolineCode(masm);
+
+  Label done;
+  masm.branchTestDouble(Assembler::NotEqual, R0, &done);
+
+  masm.unboxDouble(R0, FloatReg0);
+  masm.convertDoubleToInt32(FloatReg0, R1.scratchReg(), &done,
+                            /* negativeZeroCheck = */ false);
+  masm.tagValue(JSVAL_TYPE_INT32, R1.scratchReg(), R0);
+
+  masm.bind(&done);
+  masm.abiret();
+}
+
+bool JitRuntime::generateTLEventVM(MacroAssembler& masm,
+                                   const VMFunctionData& f, bool enter) {
+#ifdef JS_TRACE_LOGGING
+  bool vmEventEnabled = TraceLogTextIdEnabled(TraceLogger_VM);
+  bool vmSpecificEventEnabled = TraceLogTextIdEnabled(TraceLogger_VMSpecific);
+
+  if (vmEventEnabled || vmSpecificEventEnabled) {
+    AllocatableRegisterSet regs(RegisterSet::Volatile());
+    Register loggerReg = regs.takeAnyGeneral();
+    masm.Push(loggerReg);
+    masm.loadTraceLogger(loggerReg);
+
+    if (vmEventEnabled) {
+      if (enter) {
+        masm.tracelogStartId(loggerReg, TraceLogger_VM, /* force = */ true);
+      } else {
+        masm.tracelogStopId(loggerReg, TraceLogger_VM, /* force = */ true);
+      }
+    }
+    if (vmSpecificEventEnabled) {
+      TraceLoggerEvent event(f.name());
+      if (!event.hasTextId()) {
+        return false;
+      }
+
+      if (enter) {
+        masm.tracelogStartId(loggerReg, event.textId(), /* force = */ true);
+      } else {
+        masm.tracelogStopId(loggerReg, event.textId(), /* force = */ true);
+      }
+    }
+
+    masm.Pop(loggerReg);
+  }
+#endif
+
+  return true;
+}
+
+void CodeGenerator::visitCharCodeAt(LCharCodeAt* lir) {
+  Register str = ToRegister(lir->str());
+  Register index = ToRegister(lir->index());
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+
+  using Fn = bool (*)(JSContext*, HandleString, int32_t, uint32_t*);
+  OutOfLineCode* ool = oolCallVM<Fn, jit::CharCodeAt>(lir, ArgList(str, index),
+                                                      StoreRegisterTo(output));
+  masm.loadStringChar(str, index, output, temp, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitFromCharCode(LFromCharCode* lir) {
+  Register code = ToRegister(lir->code());
+  Register output = ToRegister(lir->output());
+
+  using Fn = JSLinearString* (*)(JSContext*, int32_t);
+  OutOfLineCode* ool = oolCallVM<Fn, jit::StringFromCharCode>(
+      lir, ArgList(code), StoreRegisterTo(output));
+
+  // OOL path if code >= UNIT_STATIC_LIMIT.
+  masm.boundsCheck32PowerOfTwo(code, StaticStrings::UNIT_STATIC_LIMIT,
+                               ool->entry());
+
+  masm.movePtr(ImmPtr(&gen->runtime->staticStrings().unitStaticTable), output);
+  masm.loadPtr(BaseIndex(output, code, ScalePointer), output);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitFromCodePoint(LFromCodePoint* lir) {
+  Register codePoint = ToRegister(lir->codePoint());
+  Register output = ToRegister(lir->output());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  LSnapshot* snapshot = lir->snapshot();
+
+  // The OOL path is only taken when we can't allocate the inline string.
+  using Fn = JSString* (*)(JSContext*, int32_t);
+  OutOfLineCode* ool = oolCallVM<Fn, jit::StringFromCodePoint>(
+      lir, ArgList(codePoint), StoreRegisterTo(output));
+
+  Label isTwoByte;
+  Label* done = ool->rejoin();
+
+  static_assert(
+      StaticStrings::UNIT_STATIC_LIMIT - 1 == JSString::MAX_LATIN1_CHAR,
+      "Latin-1 strings can be loaded from static strings");
+  masm.boundsCheck32PowerOfTwo(codePoint, StaticStrings::UNIT_STATIC_LIMIT,
+                               &isTwoByte);
+  {
+    masm.movePtr(ImmPtr(&gen->runtime->staticStrings().unitStaticTable),
+                 output);
+    masm.loadPtr(BaseIndex(output, codePoint, ScalePointer), output);
+    masm.jump(done);
+  }
+  masm.bind(&isTwoByte);
+  {
+    // Use a bailout if the input is not a valid code point, because
+    // MFromCodePoint is movable and it'd be observable when a moved
+    // fromCodePoint throws an exception before its actual call site.
+    bailoutCmp32(Assembler::Above, codePoint, Imm32(unicode::NonBMPMax),
+                 snapshot);
+
+    // Allocate a JSThinInlineString.
+    {
+      static_assert(JSThinInlineString::MAX_LENGTH_TWO_BYTE >= 2,
+                    "JSThinInlineString can hold a supplementary code point");
+
+      uint32_t flags = JSString::INIT_THIN_INLINE_FLAGS;
+      masm.newGCString(output, temp1, ool->entry(),
+                       gen->stringsCanBeInNursery());
+      masm.store32(Imm32(flags), Address(output, JSString::offsetOfFlags()));
+    }
+
+    Label isSupplementary;
+    masm.branch32(Assembler::AboveOrEqual, codePoint, Imm32(unicode::NonBMPMin),
+                  &isSupplementary);
+    {
+      // Store length.
+      masm.store32(Imm32(1), Address(output, JSString::offsetOfLength()));
+
+      // Load chars pointer in temp1.
+      masm.loadInlineStringCharsForStore(output, temp1);
+
+      masm.store16(codePoint, Address(temp1, 0));
+
+      masm.jump(done);
+    }
+    masm.bind(&isSupplementary);
+    {
+      // Store length.
+      masm.store32(Imm32(2), Address(output, JSString::offsetOfLength()));
+
+      // Load chars pointer in temp1.
+      masm.loadInlineStringCharsForStore(output, temp1);
+
+      // Inlined unicode::LeadSurrogate(uint32_t).
+      masm.move32(codePoint, temp2);
+      masm.rshift32(Imm32(10), temp2);
+      masm.add32(Imm32(unicode::LeadSurrogateMin - (unicode::NonBMPMin >> 10)),
+                 temp2);
+
+      masm.store16(temp2, Address(temp1, 0));
+
+      // Inlined unicode::TrailSurrogate(uint32_t).
+      masm.move32(codePoint, temp2);
+      masm.and32(Imm32(0x3FF), temp2);
+      masm.or32(Imm32(unicode::TrailSurrogateMin), temp2);
+
+      masm.store16(temp2, Address(temp1, sizeof(char16_t)));
+    }
+  }
+
+  masm.bind(done);
+}
+
+void CodeGenerator::visitStringConvertCase(LStringConvertCase* lir) {
+  pushArg(ToRegister(lir->string()));
+
+  using Fn = JSString* (*)(JSContext*, HandleString);
+  if (lir->mir()->mode() == MStringConvertCase::LowerCase) {
+    callVM<Fn, js::StringToLowerCase>(lir);
+  } else {
+    callVM<Fn, js::StringToUpperCase>(lir);
+  }
+}
+
+void CodeGenerator::visitStringSplit(LStringSplit* lir) {
+  pushArg(Imm32(INT32_MAX));
+  pushArg(ToRegister(lir->separator()));
+  pushArg(ToRegister(lir->string()));
+
+  using Fn = ArrayObject* (*)(JSContext*, HandleString, HandleString, uint32_t);
+  callVM<Fn, js::StringSplitString>(lir);
+}
+
+void CodeGenerator::visitInitializedLength(LInitializedLength* lir) {
+  Address initLength(ToRegister(lir->elements()),
+                     ObjectElements::offsetOfInitializedLength());
+  masm.load32(initLength, ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitSetInitializedLength(LSetInitializedLength* lir) {
+  Address initLength(ToRegister(lir->elements()),
+                     ObjectElements::offsetOfInitializedLength());
+  SetLengthFromIndex(masm, lir->index(), initLength);
+}
+
+void CodeGenerator::visitNotO(LNotO* lir) {
+  auto* ool = new (alloc()) OutOfLineTestObjectWithLabels();
+  addOutOfLineCode(ool, lir->mir());
+
+  Label* ifEmulatesUndefined = ool->label1();
+  Label* ifDoesntEmulateUndefined = ool->label2();
+
+  Register objreg = ToRegister(lir->input());
+  Register output = ToRegister(lir->output());
+  branchTestObjectEmulatesUndefined(objreg, ifEmulatesUndefined,
+                                    ifDoesntEmulateUndefined, output, ool);
+  // fall through
+
+  Label join;
+
+  masm.move32(Imm32(0), output);
+  masm.jump(&join);
+
+  masm.bind(ifEmulatesUndefined);
+  masm.move32(Imm32(1), output);
+
+  masm.bind(&join);
+}
+
+void CodeGenerator::visitNotV(LNotV* lir) {
+  MDefinition* operand = lir->mir()->input();
+
+  auto* ool = new (alloc()) OutOfLineTestObjectWithLabels();
+  addOutOfLineCode(ool, lir->mir());
+
+  Label* ifTruthy = ool->label1();
+  Label* ifFalsy = ool->label2();
+
+  testValueTruthyKernel(ToValue(lir, LNotV::Input), lir->temp1(), lir->temp2(),
+                        ToFloatRegister(lir->tempFloat()), ifTruthy, ifFalsy,
+                        ool, operand);
+
+  Label join;
+  Register output = ToRegister(lir->output());
+
+  // Note that the testValueTruthyKernel call above may choose to fall through
+  // to ifTruthy instead of branching there.
+  masm.bind(ifTruthy);
+  masm.move32(Imm32(0), output);
+  masm.jump(&join);
+
+  masm.bind(ifFalsy);
+  masm.move32(Imm32(1), output);
+
+  // both branches meet here.
+  masm.bind(&join);
+}
+
+void CodeGenerator::visitBoundsCheck(LBoundsCheck* lir) {
+  const LAllocation* index = lir->index();
+  const LAllocation* length = lir->length();
+  LSnapshot* snapshot = lir->snapshot();
+
+  if (index->isConstant()) {
+    // Use uint32 so that the comparison is unsigned.
+    uint32_t idx = ToInt32(index);
+    if (length->isConstant()) {
+      uint32_t len = ToInt32(lir->length());
+      if (idx < len) {
+        return;
+      }
+      bailout(snapshot);
+      return;
+    }
+
+    if (length->isRegister()) {
+      bailoutCmp32(Assembler::BelowOrEqual, ToRegister(length), Imm32(idx),
+                   snapshot);
+    } else {
+      bailoutCmp32(Assembler::BelowOrEqual, ToAddress(length), Imm32(idx),
+                   snapshot);
+    }
+    return;
+  }
+
+  Register indexReg = ToRegister(index);
+  if (length->isConstant()) {
+    bailoutCmp32(Assembler::AboveOrEqual, indexReg, Imm32(ToInt32(length)),
+                 snapshot);
+  } else if (length->isRegister()) {
+    bailoutCmp32(Assembler::BelowOrEqual, ToRegister(length), indexReg,
+                 snapshot);
+  } else {
+    bailoutCmp32(Assembler::BelowOrEqual, ToAddress(length), indexReg,
+                 snapshot);
+  }
+}
+
+void CodeGenerator::visitBoundsCheckRange(LBoundsCheckRange* lir) {
+  int32_t min = lir->mir()->minimum();
+  int32_t max = lir->mir()->maximum();
+  MOZ_ASSERT(max >= min);
+
+  const LAllocation* length = lir->length();
+  LSnapshot* snapshot = lir->snapshot();
+  Register temp = ToRegister(lir->getTemp(0));
+  if (lir->index()->isConstant()) {
+    int32_t nmin, nmax;
+    int32_t index = ToInt32(lir->index());
+    if (SafeAdd(index, min, &nmin) && SafeAdd(index, max, &nmax) && nmin >= 0) {
+      if (length->isRegister()) {
+        bailoutCmp32(Assembler::BelowOrEqual, ToRegister(length), Imm32(nmax),
+                     snapshot);
+      } else {
+        bailoutCmp32(Assembler::BelowOrEqual, ToAddress(length), Imm32(nmax),
+                     snapshot);
+      }
+      return;
+    }
+    masm.mov(ImmWord(index), temp);
+  } else {
+    masm.mov(ToRegister(lir->index()), temp);
+  }
+
+  // If the minimum and maximum differ then do an underflow check first.
+  // If the two are the same then doing an unsigned comparison on the
+  // length will also catch a negative index.
+  if (min != max) {
+    if (min != 0) {
+      Label bail;
+      masm.branchAdd32(Assembler::Overflow, Imm32(min), temp, &bail);
+      bailoutFrom(&bail, snapshot);
+    }
+
+    bailoutCmp32(Assembler::LessThan, temp, Imm32(0), snapshot);
+
+    if (min != 0) {
+      int32_t diff;
+      if (SafeSub(max, min, &diff)) {
+        max = diff;
+      } else {
+        masm.sub32(Imm32(min), temp);
+      }
+    }
+  }
+
+  // Compute the maximum possible index. No overflow check is needed when
+  // max > 0. We can only wraparound to a negative number, which will test as
+  // larger than all nonnegative numbers in the unsigned comparison, and the
+  // length is required to be nonnegative (else testing a negative length
+  // would succeed on any nonnegative index).
+  if (max != 0) {
+    if (max < 0) {
+      Label bail;
+      masm.branchAdd32(Assembler::Overflow, Imm32(max), temp, &bail);
+      bailoutFrom(&bail, snapshot);
+    } else {
+      masm.add32(Imm32(max), temp);
+    }
+  }
+
+  if (length->isRegister()) {
+    bailoutCmp32(Assembler::BelowOrEqual, ToRegister(length), temp, snapshot);
+  } else {
+    bailoutCmp32(Assembler::BelowOrEqual, ToAddress(length), temp, snapshot);
+  }
+}
+
+void CodeGenerator::visitBoundsCheckLower(LBoundsCheckLower* lir) {
+  int32_t min = lir->mir()->minimum();
+  bailoutCmp32(Assembler::LessThan, ToRegister(lir->index()), Imm32(min),
+               lir->snapshot());
+}
+
+void CodeGenerator::visitSpectreMaskIndex(LSpectreMaskIndex* lir) {
+  MOZ_ASSERT(JitOptions.spectreIndexMasking);
+
+  const LAllocation* length = lir->length();
+  Register index = ToRegister(lir->index());
+  Register output = ToRegister(lir->output());
+
+  if (length->isRegister()) {
+    masm.spectreMaskIndex32(index, ToRegister(length), output);
+  } else {
+    masm.spectreMaskIndex32(index, ToAddress(length), output);
+  }
+}
+
+class OutOfLineStoreElementHole : public OutOfLineCodeBase<CodeGenerator> {
+  LInstruction* ins_;
+  Label rejoinStore_;
+  Label callStub_;
+  bool strict_;
+
+ public:
+  explicit OutOfLineStoreElementHole(LInstruction* ins, bool strict)
+      : ins_(ins), strict_(strict) {
+    MOZ_ASSERT(ins->isStoreElementHoleV() || ins->isStoreElementHoleT());
+  }
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineStoreElementHole(this);
+  }
+  LInstruction* ins() const { return ins_; }
+  Label* rejoinStore() { return &rejoinStore_; }
+  Label* callStub() { return &callStub_; }
+  bool strict() const { return strict_; }
+};
+
+void CodeGenerator::emitStoreHoleCheck(Register elements,
+                                       const LAllocation* index,
+                                       LSnapshot* snapshot) {
+  Label bail;
+  if (index->isConstant()) {
+    Address dest(elements, ToInt32(index) * sizeof(js::Value));
+    masm.branchTestMagic(Assembler::Equal, dest, &bail);
+  } else {
+    BaseObjectElementIndex dest(elements, ToRegister(index));
+    masm.branchTestMagic(Assembler::Equal, dest, &bail);
+  }
+  bailoutFrom(&bail, snapshot);
+}
+
+void CodeGenerator::emitStoreElementTyped(const LAllocation* value,
+                                          MIRType valueType,
+                                          MIRType elementType,
+                                          Register elements,
+                                          const LAllocation* index) {
+  MOZ_ASSERT(valueType != MIRType::MagicHole);
+  ConstantOrRegister v = ToConstantOrRegister(value, valueType);
+  if (index->isConstant()) {
+    Address dest(elements, ToInt32(index) * sizeof(js::Value));
+    masm.storeUnboxedValue(v, valueType, dest, elementType);
+  } else {
+    BaseObjectElementIndex dest(elements, ToRegister(index));
+    masm.storeUnboxedValue(v, valueType, dest, elementType);
+  }
+}
+
+void CodeGenerator::visitStoreElementT(LStoreElementT* store) {
+  Register elements = ToRegister(store->elements());
+  const LAllocation* index = store->index();
+
+  if (store->mir()->needsBarrier()) {
+    emitPreBarrier(elements, index);
+  }
+
+  if (store->mir()->needsHoleCheck()) {
+    emitStoreHoleCheck(elements, index, store->snapshot());
+  }
+
+  emitStoreElementTyped(store->value(), store->mir()->value()->type(),
+                        store->mir()->elementType(), elements, index);
+}
+
+void CodeGenerator::visitStoreElementV(LStoreElementV* lir) {
+  const ValueOperand value = ToValue(lir, LStoreElementV::Value);
+  Register elements = ToRegister(lir->elements());
+  const LAllocation* index = lir->index();
+
+  if (lir->mir()->needsBarrier()) {
+    emitPreBarrier(elements, index);
+  }
+
+  if (lir->mir()->needsHoleCheck()) {
+    emitStoreHoleCheck(elements, index, lir->snapshot());
+  }
+
+  if (lir->index()->isConstant()) {
+    Address dest(elements, ToInt32(lir->index()) * sizeof(js::Value));
+    masm.storeValue(value, dest);
+  } else {
+    BaseObjectElementIndex dest(elements, ToRegister(lir->index()));
+    masm.storeValue(value, dest);
+  }
+}
+
+void CodeGenerator::visitStoreHoleValueElement(LStoreHoleValueElement* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register index = ToRegister(lir->index());
+
+  Address elementsFlags(elements, ObjectElements::offsetOfFlags());
+  masm.or32(Imm32(ObjectElements::NON_PACKED), elementsFlags);
+
+  BaseObjectElementIndex element(elements, index);
+  masm.storeValue(MagicValue(JS_ELEMENTS_HOLE), element);
+}
+
+void CodeGenerator::visitStoreElementHoleT(LStoreElementHoleT* lir) {
+  OutOfLineStoreElementHole* ool =
+      new (alloc()) OutOfLineStoreElementHole(lir, current->mir()->strict());
+  addOutOfLineCode(ool, lir->mir());
+
+  Register elements = ToRegister(lir->elements());
+  Register index = ToRegister(lir->index());
+  Register spectreTemp = ToTempRegisterOrInvalid(lir->spectreTemp());
+
+  Address initLength(elements, ObjectElements::offsetOfInitializedLength());
+  masm.spectreBoundsCheck32(index, initLength, spectreTemp, ool->entry());
+
+  if (lir->mir()->needsBarrier()) {
+    emitPreBarrier(elements, lir->index());
+  }
+
+  masm.bind(ool->rejoinStore());
+  emitStoreElementTyped(lir->value(), lir->mir()->value()->type(),
+                        lir->mir()->elementType(), elements, lir->index());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitStoreElementHoleV(LStoreElementHoleV* lir) {
+  OutOfLineStoreElementHole* ool =
+      new (alloc()) OutOfLineStoreElementHole(lir, current->mir()->strict());
+  addOutOfLineCode(ool, lir->mir());
+
+  Register elements = ToRegister(lir->elements());
+  Register index = ToRegister(lir->index());
+  const ValueOperand value = ToValue(lir, LStoreElementHoleV::Value);
+  Register spectreTemp = ToTempRegisterOrInvalid(lir->spectreTemp());
+
+  Address initLength(elements, ObjectElements::offsetOfInitializedLength());
+  masm.spectreBoundsCheck32(index, initLength, spectreTemp, ool->entry());
+
+  if (lir->mir()->needsBarrier()) {
+    emitPreBarrier(elements, lir->index());
+  }
+
+  masm.bind(ool->rejoinStore());
+  masm.storeValue(value, BaseObjectElementIndex(elements, index));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineStoreElementHole(
+    OutOfLineStoreElementHole* ool) {
+  Register object, elements;
+  LInstruction* ins = ool->ins();
+  const LAllocation* index;
+  MIRType valueType;
+  mozilla::Maybe<ConstantOrRegister> value;
+  Register spectreTemp;
+
+  if (ins->isStoreElementHoleV()) {
+    LStoreElementHoleV* store = ins->toStoreElementHoleV();
+    object = ToRegister(store->object());
+    elements = ToRegister(store->elements());
+    index = store->index();
+    valueType = store->mir()->value()->type();
+    value.emplace(
+        TypedOrValueRegister(ToValue(store, LStoreElementHoleV::Value)));
+    spectreTemp = ToTempRegisterOrInvalid(store->spectreTemp());
+  } else {
+    LStoreElementHoleT* store = ins->toStoreElementHoleT();
+    object = ToRegister(store->object());
+    elements = ToRegister(store->elements());
+    index = store->index();
+    valueType = store->mir()->value()->type();
+    if (store->value()->isConstant()) {
+      value.emplace(
+          ConstantOrRegister(store->value()->toConstant()->toJSValue()));
+    } else {
+      value.emplace(
+          TypedOrValueRegister(valueType, ToAnyRegister(store->value())));
+    }
+    spectreTemp = ToTempRegisterOrInvalid(store->spectreTemp());
+  }
+
+  Register indexReg = ToRegister(index);
+
+  // If index == initializedLength, try to bump the initialized length inline.
+  // If index > initializedLength, call a stub. Note that this relies on the
+  // condition flags sticking from the incoming branch.
+  // Also note: this branch does not need Spectre mitigations, doing that for
+  // the capacity check below is sufficient.
+#if defined(JS_CODEGEN_MIPS32) || defined(JS_CODEGEN_MIPS64)
+  // Had to reimplement for MIPS because there are no flags.
+  Address initLength(elements, ObjectElements::offsetOfInitializedLength());
+  masm.branch32(Assembler::NotEqual, initLength, indexReg, ool->callStub());
+#else
+  masm.j(Assembler::NotEqual, ool->callStub());
+#endif
+
+  // Check array capacity.
+  masm.spectreBoundsCheck32(
+      indexReg, Address(elements, ObjectElements::offsetOfCapacity()),
+      spectreTemp, ool->callStub());
+
+  // Update initialized length. The capacity guard above ensures this won't
+  // overflow, due to MAX_DENSE_ELEMENTS_COUNT.
+  masm.add32(Imm32(1), indexReg);
+  masm.store32(indexReg,
+               Address(elements, ObjectElements::offsetOfInitializedLength()));
+
+  // Update length if length < initializedLength.
+  Label dontUpdate;
+  masm.branch32(Assembler::AboveOrEqual,
+                Address(elements, ObjectElements::offsetOfLength()), indexReg,
+                &dontUpdate);
+  masm.store32(indexReg, Address(elements, ObjectElements::offsetOfLength()));
+  masm.bind(&dontUpdate);
+
+  masm.sub32(Imm32(1), indexReg);
+
+  if (ins->isStoreElementHoleT() && valueType != MIRType::Double) {
+    // The inline path for StoreElementHoleT does not always store the type tag,
+    // so we do the store on the OOL path. We use MIRType::None for the element
+    // type so that emitStoreElementTyped will always store the type tag.
+    emitStoreElementTyped(ins->toStoreElementHoleT()->value(), valueType,
+                          MIRType::None, elements, index);
+    masm.jump(ool->rejoin());
+  } else {
+    // Jump to the inline path where we will store the value.
+    masm.jump(ool->rejoinStore());
+  }
+
+  masm.bind(ool->callStub());
+  saveLive(ins);
+
+  pushArg(Imm32(ool->strict()));
+  pushArg(value.ref());
+  if (index->isConstant()) {
+    pushArg(Imm32(ToInt32(index)));
+  } else {
+    pushArg(ToRegister(index));
+  }
+  pushArg(object);
+
+  using Fn = bool (*)(JSContext*, HandleNativeObject, int32_t, HandleValue,
+                      bool strict);
+  callVM<Fn, jit::SetDenseElement>(ins);
+
+  restoreLive(ins);
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitArrayPopShift(LArrayPopShift* lir) {
+  Register obj = ToRegister(lir->object());
+  Register temp1 = ToRegister(lir->temp0());
+  Register temp2 = ToRegister(lir->temp1());
+  ValueOperand out = ToOutValue(lir);
+
+  Label bail;
+  if (lir->mir()->mode() == MArrayPopShift::Pop) {
+    masm.packedArrayPop(obj, out, temp1, temp2, &bail);
+  } else {
+    MOZ_ASSERT(lir->mir()->mode() == MArrayPopShift::Shift);
+    LiveRegisterSet volatileRegs = liveVolatileRegs(lir);
+    masm.packedArrayShift(obj, out, temp1, temp2, volatileRegs, &bail);
+  }
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitArrayPush(LArrayPush* lir) {
+  Register obj = ToRegister(lir->object());
+  Register elementsTemp = ToRegister(lir->temp());
+  Register length = ToRegister(lir->output());
+  ValueOperand value = ToValue(lir, LArrayPush::Value);
+  Register spectreTemp = ToTempRegisterOrInvalid(lir->spectreTemp());
+
+  using Fn = bool (*)(JSContext*, HandleArrayObject, HandleValue, uint32_t*);
+  OutOfLineCode* ool = oolCallVM<Fn, jit::ArrayPushDense>(
+      lir, ArgList(obj, value), StoreRegisterTo(length));
+
+  // Load elements and length.
+  masm.loadPtr(Address(obj, NativeObject::offsetOfElements()), elementsTemp);
+  masm.load32(Address(elementsTemp, ObjectElements::offsetOfLength()), length);
+
+  // TODO(post-Warp): reuse/share the CacheIR implementation when IonBuilder and
+  // TI are gone (bug 1654180).
+
+  // Bailout if the incremented length does not fit in int32.
+  bailoutCmp32(Assembler::AboveOrEqual, length, Imm32(INT32_MAX),
+               lir->snapshot());
+
+  // Guard length == initializedLength.
+  Address initLength(elementsTemp, ObjectElements::offsetOfInitializedLength());
+  masm.branch32(Assembler::NotEqual, initLength, length, ool->entry());
+
+  // Guard length < capacity.
+  Address capacity(elementsTemp, ObjectElements::offsetOfCapacity());
+  masm.spectreBoundsCheck32(length, capacity, spectreTemp, ool->entry());
+
+  // Do the store.
+  masm.storeValue(value, BaseObjectElementIndex(elementsTemp, length));
+
+  masm.add32(Imm32(1), length);
+
+  // Update length and initialized length.
+  masm.store32(length, Address(elementsTemp, ObjectElements::offsetOfLength()));
+  masm.store32(length, Address(elementsTemp,
+                               ObjectElements::offsetOfInitializedLength()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitArraySlice(LArraySlice* lir) {
+  Register object = ToRegister(lir->object());
+  Register begin = ToRegister(lir->begin());
+  Register end = ToRegister(lir->end());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+
+  Label call, fail;
+
+  Label bail;
+  masm.branchArrayIsNotPacked(object, temp1, temp2, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+
+  // Try to allocate an object.
+  TemplateObject templateObject(lir->mir()->templateObj());
+  masm.createGCObject(temp1, temp2, templateObject, lir->mir()->initialHeap(),
+                      &fail);
+
+  masm.jump(&call);
+  {
+    masm.bind(&fail);
+    masm.movePtr(ImmPtr(nullptr), temp1);
+  }
+  masm.bind(&call);
+
+  pushArg(temp1);
+  pushArg(end);
+  pushArg(begin);
+  pushArg(object);
+
+  using Fn =
+      JSObject* (*)(JSContext*, HandleObject, int32_t, int32_t, HandleObject);
+  callVM<Fn, ArraySliceDense>(lir);
+}
+
+void CodeGenerator::visitArrayJoin(LArrayJoin* lir) {
+  Label skipCall;
+
+  Register output = ToRegister(lir->output());
+  Register sep = ToRegister(lir->separator());
+  Register array = ToRegister(lir->array());
+  Register temp = ToRegister(lir->temp());
+
+  // Fast path for simple length <= 1 cases.
+  {
+    masm.loadPtr(Address(array, NativeObject::offsetOfElements()), temp);
+    Address length(temp, ObjectElements::offsetOfLength());
+    Address initLength(temp, ObjectElements::offsetOfInitializedLength());
+
+    // Check for length == 0
+    Label notEmpty;
+    masm.branch32(Assembler::NotEqual, length, Imm32(0), &notEmpty);
+    const JSAtomState& names = GetJitContext()->runtime->names();
+    masm.movePtr(ImmGCPtr(names.empty), output);
+    masm.jump(&skipCall);
+
+    masm.bind(&notEmpty);
+    Label notSingleString;
+    // Check for length == 1, initializedLength >= 1, arr[0].isString()
+    masm.branch32(Assembler::NotEqual, length, Imm32(1), &notSingleString);
+    masm.branch32(Assembler::LessThan, initLength, Imm32(1), &notSingleString);
+
+    Address elem0(temp, 0);
+    masm.branchTestString(Assembler::NotEqual, elem0, &notSingleString);
+
+    // At this point, 'output' can be used as a scratch register, since we're
+    // guaranteed to succeed.
+    masm.unboxString(elem0, output);
+    masm.jump(&skipCall);
+    masm.bind(&notSingleString);
+  }
+
+  pushArg(sep);
+  pushArg(array);
+
+  using Fn = JSString* (*)(JSContext*, HandleObject, HandleString);
+  callVM<Fn, jit::ArrayJoin>(lir);
+  masm.bind(&skipCall);
+}
+
+void CodeGenerator::visitGetIteratorCache(LGetIteratorCache* lir) {
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+  TypedOrValueRegister val = toConstantOrRegister(lir, LGetIteratorCache::Value,
+                                                  lir->mir()->value()->type())
+                                 .reg();
+  Register output = ToRegister(lir->output());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+
+  IonGetIteratorIC ic(liveRegs, val, output, temp1, temp2);
+  addIC(lir, allocateIC(ic));
+}
+
+void CodeGenerator::visitOptimizeSpreadCallCache(
+    LOptimizeSpreadCallCache* lir) {
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+  ValueOperand val = ToValue(lir, LOptimizeSpreadCallCache::Value);
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+
+  IonOptimizeSpreadCallIC ic(liveRegs, val, output, temp);
+  addIC(lir, allocateIC(ic));
+}
+
+void CodeGenerator::visitIteratorMore(LIteratorMore* lir) {
+  const Register obj = ToRegister(lir->object());
+  const ValueOperand output = ToOutValue(lir);
+  const Register temp = ToRegister(lir->temp());
+
+  masm.iteratorMore(obj, output, temp);
+}
+
+void CodeGenerator::visitIsNoIterAndBranch(LIsNoIterAndBranch* lir) {
+  ValueOperand input = ToValue(lir, LIsNoIterAndBranch::Input);
+  Label* ifTrue = getJumpLabelForBranch(lir->ifTrue());
+  Label* ifFalse = getJumpLabelForBranch(lir->ifFalse());
+
+  masm.branchTestMagic(Assembler::Equal, input, ifTrue);
+
+  if (!isNextBlock(lir->ifFalse()->lir())) {
+    masm.jump(ifFalse);
+  }
+}
+
+void CodeGenerator::visitIteratorEnd(LIteratorEnd* lir) {
+  const Register obj = ToRegister(lir->object());
+  const Register temp1 = ToRegister(lir->temp1());
+  const Register temp2 = ToRegister(lir->temp2());
+  const Register temp3 = ToRegister(lir->temp3());
+
+  masm.iteratorClose(obj, temp1, temp2, temp3);
+}
+
+void CodeGenerator::visitArgumentsLength(LArgumentsLength* lir) {
+  // read number of actual arguments from the JS frame.
+  Register argc = ToRegister(lir->output());
+  Address ptr(masm.getStackPointer(),
+              frameSize() + JitFrameLayout::offsetOfNumActualArgs());
+
+  masm.loadPtr(ptr, argc);
+}
+
+void CodeGenerator::visitGetFrameArgument(LGetFrameArgument* lir) {
+  ValueOperand result = ToOutValue(lir);
+  const LAllocation* index = lir->index();
+  size_t argvOffset = frameSize() + JitFrameLayout::offsetOfActualArgs();
+
+  if (index->isConstant()) {
+    int32_t i = index->toConstant()->toInt32();
+    Address argPtr(masm.getStackPointer(), sizeof(Value) * i + argvOffset);
+    masm.loadValue(argPtr, result);
+  } else {
+    Register i = ToRegister(index);
+    BaseValueIndex argPtr(masm.getStackPointer(), i, argvOffset);
+    masm.loadValue(argPtr, result);
+  }
+}
+
+void CodeGenerator::emitRest(LInstruction* lir, Register array,
+                             Register numActuals, Register temp0,
+                             Register temp1, unsigned numFormals,
+                             JSObject* templateObject, bool saveAndRestore,
+                             Register resultreg) {
+  // Compute actuals() + numFormals.
+  size_t actualsOffset = frameSize() + JitFrameLayout::offsetOfActualArgs();
+  masm.moveStackPtrTo(temp1);
+  masm.addPtr(Imm32(sizeof(Value) * numFormals + actualsOffset), temp1);
+
+  // Compute numActuals - numFormals.
+  Label emptyLength, joinLength;
+  masm.movePtr(numActuals, temp0);
+  masm.branch32(Assembler::LessThanOrEqual, temp0, Imm32(numFormals),
+                &emptyLength);
+  masm.sub32(Imm32(numFormals), temp0);
+  masm.jump(&joinLength);
+  {
+    masm.bind(&emptyLength);
+    masm.move32(Imm32(0), temp0);
+  }
+  masm.bind(&joinLength);
+
+  if (saveAndRestore) {
+    saveLive(lir);
+  }
+
+  pushArg(array);
+  pushArg(ImmGCPtr(templateObject));
+  pushArg(temp1);
+  pushArg(temp0);
+
+  using Fn =
+      JSObject* (*)(JSContext*, uint32_t, Value*, HandleObject, HandleObject);
+  callVM<Fn, InitRestParameter>(lir);
+
+  if (saveAndRestore) {
+    storePointerResultTo(resultreg);
+    restoreLive(lir);
+  }
+}
+
+void CodeGenerator::visitRest(LRest* lir) {
+  Register numActuals = ToRegister(lir->numActuals());
+  Register temp0 = ToRegister(lir->getTemp(0));
+  Register temp1 = ToRegister(lir->getTemp(1));
+  Register temp2 = ToRegister(lir->getTemp(2));
+  unsigned numFormals = lir->mir()->numFormals();
+  ArrayObject* templateObject = lir->mir()->templateObject();
+
+  Label joinAlloc, failAlloc;
+  TemplateObject templateObj(templateObject);
+  masm.createGCObject(temp2, temp0, templateObj, gc::DefaultHeap, &failAlloc);
+  masm.jump(&joinAlloc);
+  {
+    masm.bind(&failAlloc);
+    masm.movePtr(ImmPtr(nullptr), temp2);
+  }
+  masm.bind(&joinAlloc);
+
+  emitRest(lir, temp2, numActuals, temp0, temp1, numFormals, templateObject,
+           false, ToRegister(lir->output()));
+}
+
+// Create a stackmap from the given safepoint, with the structure:
+//
+//   <reg dump area, if trap>
+//   |       ++ <body (general spill)>
+//   |               ++ <space for Frame>
+//   |                       ++ <inbound args>
+//   |                                       |
+//   Lowest Addr                             Highest Addr
+//
+// The caller owns the resulting stackmap.  This assumes a grow-down stack.
+//
+// For non-debug builds, if the stackmap would contain no pointers, no
+// stackmap is created, and nullptr is returned.  For a debug build, a
+// stackmap is always created and returned.
+static bool CreateStackMapFromLSafepoint(LSafepoint& safepoint,
+                                         const MachineState& trapExitLayout,
+                                         size_t trapExitLayoutNumWords,
+                                         size_t nInboundStackArgBytes,
+                                         wasm::StackMap** result) {
+  // Ensure this is defined on all return paths.
+  *result = nullptr;
+
+  // The size of the wasm::Frame itself.
+  const size_t nFrameBytes = sizeof(wasm::Frame);
+
+  // This is the number of bytes in the general spill area, below the Frame.
+  const size_t nBodyBytes = safepoint.framePushedAtStackMapBase();
+
+  // This is the number of bytes in the general spill area, the Frame, and the
+  // incoming args, but not including any trap (register dump) area.
+  const size_t nNonTrapBytes = nBodyBytes + nFrameBytes + nInboundStackArgBytes;
+  MOZ_ASSERT(nNonTrapBytes % sizeof(void*) == 0);
+
+  // This is the total number of bytes covered by the map.
+  const DebugOnly<size_t> nTotalBytes =
+      nNonTrapBytes +
+      (safepoint.isWasmTrap() ? (trapExitLayoutNumWords * sizeof(void*)) : 0);
+
+  // Create the stackmap initially in this vector.  Since most frames will
+  // contain 128 or fewer words, heap allocation is avoided in the majority of
+  // cases.  vec[0] is for the lowest address in the map, vec[N-1] is for the
+  // highest address in the map.
+  wasm::StackMapBoolVector vec;
+
+  // Keep track of whether we've actually seen any refs.
+  bool hasRefs = false;
+
+  // REG DUMP AREA, if any.
+  const LiveGeneralRegisterSet gcRegs = safepoint.gcRegs();
+  GeneralRegisterForwardIterator gcRegsIter(gcRegs);
+  if (safepoint.isWasmTrap()) {
+    // Deal with roots in registers.  This can only happen for safepoints
+    // associated with a trap.  For safepoints associated with a call, we
+    // don't expect to have any live values in registers, hence no roots in
+    // registers.
+    if (!vec.appendN(false, trapExitLayoutNumWords)) {
+      return false;
+    }
+    for (; gcRegsIter.more(); ++gcRegsIter) {
+      Register reg = *gcRegsIter;
+      size_t offsetFromTop =
+          reinterpret_cast<size_t>(trapExitLayout.address(reg));
+
+      // If this doesn't hold, the associated register wasn't saved by
+      // the trap exit stub.  Better to crash now than much later, in
+      // some obscure place, and possibly with security consequences.
+      MOZ_RELEASE_ASSERT(offsetFromTop < trapExitLayoutNumWords);
+
+      // offsetFromTop is an offset in words down from the highest
+      // address in the exit stub save area.  Switch it around to be an
+      // offset up from the bottom of the (integer register) save area.
+      size_t offsetFromBottom = trapExitLayoutNumWords - 1 - offsetFromTop;
+
+      vec[offsetFromBottom] = true;
+      hasRefs = true;
+    }
+  } else {
+    // This map is associated with a call instruction.  We expect there to be
+    // no live ref-carrying registers, and if there are we're in deep trouble.
+    MOZ_RELEASE_ASSERT(!gcRegsIter.more());
+  }
+
+  // BODY (GENERAL SPILL) AREA and FRAME and INCOMING ARGS
+  // Deal with roots on the stack.
+  size_t wordsSoFar = vec.length();
+  if (!vec.appendN(false, nNonTrapBytes / sizeof(void*))) {
+    return false;
+  }
+  const LSafepoint::SlotList& gcSlots = safepoint.gcSlots();
+  for (SafepointSlotEntry gcSlot : gcSlots) {
+    // The following needs to correspond with JitFrameLayout::slotRef
+    // gcSlot.stack == 0 means the slot is in the args area
+    if (gcSlot.stack) {
+      // It's a slot in the body allocation, so .slot is interpreted
+      // as an index downwards from the Frame*
+      MOZ_ASSERT(gcSlot.slot <= nBodyBytes);
+      uint32_t offsetInBytes = nBodyBytes - gcSlot.slot;
+      MOZ_ASSERT(offsetInBytes % sizeof(void*) == 0);
+      vec[wordsSoFar + offsetInBytes / sizeof(void*)] = true;
+    } else {
+      // It's an argument slot
+      MOZ_ASSERT(gcSlot.slot < nInboundStackArgBytes);
+      uint32_t offsetInBytes = nBodyBytes + nFrameBytes + gcSlot.slot;
+      MOZ_ASSERT(offsetInBytes % sizeof(void*) == 0);
+      vec[wordsSoFar + offsetInBytes / sizeof(void*)] = true;
+    }
+    hasRefs = true;
+  }
+
+#ifndef DEBUG
+  // We saw no references, and this is a non-debug build, so don't bother
+  // building the stackmap.
+  if (!hasRefs) {
+    return true;
+  }
+#endif
+
+  // Convert vec into a wasm::StackMap.
+  MOZ_ASSERT(vec.length() * sizeof(void*) == nTotalBytes);
+  wasm::StackMap* stackMap =
+      wasm::ConvertStackMapBoolVectorToStackMap(vec, hasRefs);
+  if (!stackMap) {
+    return false;
+  }
+  if (safepoint.isWasmTrap()) {
+    stackMap->setExitStubWords(trapExitLayoutNumWords);
+  }
+
+  // Record in the map, how far down from the highest address the Frame* is.
+  // Take the opportunity to check that we haven't marked any part of the
+  // Frame itself as a pointer.
+  stackMap->setFrameOffsetFromTop((nInboundStackArgBytes + nFrameBytes) /
+                                  sizeof(void*));
+#ifdef DEBUG
+  for (uint32_t i = 0; i < nFrameBytes / sizeof(void*); i++) {
+    MOZ_ASSERT(stackMap->getBit(stackMap->numMappedWords -
+                                stackMap->frameOffsetFromTop + i) == 0);
+  }
+#endif
+
+  *result = stackMap;
+  return true;
+}
+
+bool CodeGenerator::generateWasm(wasm::TypeIdDesc funcTypeId,
+                                 wasm::BytecodeOffset trapOffset,
+                                 const wasm::ArgTypeVector& argTypes,
+                                 const MachineState& trapExitLayout,
+                                 size_t trapExitLayoutNumWords,
+                                 wasm::FuncOffsets* offsets,
+                                 wasm::StackMaps* stackMaps) {
+  JitSpew(JitSpew_Codegen, "# Emitting wasm code");
+  setUseWasmStackArgumentAbi();
+
+  size_t nInboundStackArgBytes = StackArgAreaSizeUnaligned(argTypes);
+
+  wasm::GenerateFunctionPrologue(masm, funcTypeId, mozilla::Nothing(), offsets);
+
+  MOZ_ASSERT(masm.framePushed() == 0);
+
+  if (omitOverRecursedCheck()) {
+    masm.reserveStack(frameSize());
+  } else {
+    std::pair<CodeOffset, uint32_t> pair =
+        masm.wasmReserveStackChecked(frameSize(), trapOffset);
+    CodeOffset trapInsnOffset = pair.first;
+    size_t nBytesReservedBeforeTrap = pair.second;
+
+    wasm::StackMap* functionEntryStackMap = nullptr;
+    if (!CreateStackMapForFunctionEntryTrap(
+            argTypes, trapExitLayout, trapExitLayoutNumWords,
+            nBytesReservedBeforeTrap, nInboundStackArgBytes,
+            &functionEntryStackMap)) {
+      return false;
+    }
+
+    // In debug builds, we'll always have a stack map, even if there are no
+    // refs to track.
+    MOZ_ASSERT(functionEntryStackMap);
+
+    if (functionEntryStackMap &&
+        !stackMaps->add((uint8_t*)(uintptr_t)trapInsnOffset.offset(),
+                        functionEntryStackMap)) {
+      functionEntryStackMap->destroy();
+      return false;
+    }
+  }
+
+  MOZ_ASSERT(masm.framePushed() == frameSize());
+
+  if (!generateBody()) {
+    return false;
+  }
+
+  masm.bind(&returnLabel_);
+  wasm::GenerateFunctionEpilogue(masm, frameSize(), offsets);
+
+#if defined(JS_ION_PERF)
+  // Note the end of the inline code and start of the OOL code.
+  gen->perfSpewer().noteEndInlineCode(masm);
+#endif
+
+  if (!generateOutOfLineCode()) {
+    return false;
+  }
+
+  masm.flush();
+  if (masm.oom()) {
+    return false;
+  }
+
+  offsets->end = masm.currentOffset();
+
+  MOZ_ASSERT(!masm.failureLabel()->used());
+  MOZ_ASSERT(snapshots_.listSize() == 0);
+  MOZ_ASSERT(snapshots_.RVATableSize() == 0);
+  MOZ_ASSERT(recovers_.size() == 0);
+  MOZ_ASSERT(bailouts_.empty());
+  MOZ_ASSERT(graph.numConstants() == 0);
+  MOZ_ASSERT(osiIndices_.empty());
+  MOZ_ASSERT(icList_.empty());
+  MOZ_ASSERT(safepoints_.size() == 0);
+  MOZ_ASSERT(!scriptCounts_);
+
+  // Convert the safepoints to stackmaps and add them to our running
+  // collection thereof.
+  for (CodegenSafepointIndex& index : safepointIndices_) {
+    wasm::StackMap* stackMap = nullptr;
+    if (!CreateStackMapFromLSafepoint(*index.safepoint(), trapExitLayout,
+                                      trapExitLayoutNumWords,
+                                      nInboundStackArgBytes, &stackMap)) {
+      return false;
+    }
+
+    // In debug builds, we'll always have a stack map.
+    MOZ_ASSERT(stackMap);
+    if (!stackMap) {
+      continue;
+    }
+
+    if (!stackMaps->add((uint8_t*)(uintptr_t)index.displacement(), stackMap)) {
+      stackMap->destroy();
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool CodeGenerator::generate() {
+  JitSpew(JitSpew_Codegen, "# Emitting code for script %s:%u:%u",
+          gen->outerInfo().script()->filename(),
+          gen->outerInfo().script()->lineno(),
+          gen->outerInfo().script()->column());
+
+  // Initialize native code table with an entry to the start of
+  // top-level script.
+  InlineScriptTree* tree = gen->outerInfo().inlineScriptTree();
+  jsbytecode* startPC = tree->script()->code();
+  BytecodeSite* startSite = new (gen->alloc()) BytecodeSite(tree, startPC);
+  if (!addNativeToBytecodeEntry(startSite)) {
+    return false;
+  }
+
+  if (!safepoints_.init(gen->alloc())) {
+    return false;
+  }
+
+  if (!generatePrologue()) {
+    return false;
+  }
+
+  if (frameClass_ != FrameSizeClass::None()) {
+    deoptTable_.emplace(gen->jitRuntime()->getBailoutTable(frameClass_));
+  }
+
+  // Reset native => bytecode map table with top-level script and startPc.
+  if (!addNativeToBytecodeEntry(startSite)) {
+    return false;
+  }
+
+  if (!generateBody()) {
+    return false;
+  }
+
+  // Reset native => bytecode map table with top-level script and startPc.
+  if (!addNativeToBytecodeEntry(startSite)) {
+    return false;
+  }
+
+  if (!generateEpilogue()) {
+    return false;
+  }
+
+  // Reset native => bytecode map table with top-level script and startPc.
+  if (!addNativeToBytecodeEntry(startSite)) {
+    return false;
+  }
+
+  generateInvalidateEpilogue();
+#if defined(JS_ION_PERF)
+  // Note the end of the inline code and start of the OOL code.
+  perfSpewer_.noteEndInlineCode(masm);
+#endif
+
+  // native => bytecode entries for OOL code will be added
+  // by CodeGeneratorShared::generateOutOfLineCode
+  if (!generateOutOfLineCode()) {
+    return false;
+  }
+
+  // Add terminal entry.
+  if (!addNativeToBytecodeEntry(startSite)) {
+    return false;
+  }
+
+  // Dump Native to bytecode entries to spew.
+  dumpNativeToBytecodeEntries();
+
+  return !masm.oom();
+}
+
+static bool AddInlinedCompilations(JSContext* cx, HandleScript script,
+                                   IonCompilationId compilationId,
+                                   const WarpSnapshot* snapshot,
+                                   bool* isValid) {
+  MOZ_ASSERT(!*isValid);
+  RecompileInfo recompileInfo(script, compilationId);
+
+  JitZone* jitZone = cx->zone()->jitZone();
+
+  for (const auto* scriptSnapshot : snapshot->scripts()) {
+    JSScript* inlinedScript = scriptSnapshot->script();
+    if (inlinedScript == script) {
+      continue;
+    }
+
+    // TODO(post-Warp): This matches FinishCompilation and is necessary to
+    // ensure in-progress compilations are canceled when an inlined functon
+    // becomes a debuggee. See the breakpoint-14.js jit-test.
+    // When TI is gone, try to clean this up by moving AddInlinedCompilations to
+    // WarpOracle so that we can handle this as part of addPendingRecompile
+    // instead of requiring this separate check.
+    if (inlinedScript->isDebuggee()) {
+      *isValid = false;
+      return true;
+    }
+
+    if (!jitZone->addInlinedCompilation(recompileInfo, inlinedScript)) {
+      return false;
+    }
+  }
+
+  *isValid = true;
+  return true;
+}
+
+bool CodeGenerator::link(JSContext* cx, const WarpSnapshot* snapshot) {
+  // We cancel off-thread Ion compilations in a few places during GC, but if
+  // this compilation was performed off-thread it will already have been
+  // removed from the relevant lists by this point. Don't allow GC here.
+  JS::AutoAssertNoGC nogc(cx);
+
+  RootedScript script(cx, gen->outerInfo().script());
+  MOZ_ASSERT(!script->hasIonScript());
+
+  // Perform any read barriers which were skipped while compiling the
+  // script, which may have happened off-thread.
+  const JitRealm* jr = gen->realm->jitRealm();
+  jr->performStubReadBarriers(realmStubsToReadBarrier_);
+
+  if (scriptCounts_ && !script->hasScriptCounts() &&
+      !script->initScriptCounts(cx)) {
+    return false;
+  }
+
+  // Check to make sure we didn't have a mid-build invalidation. If so, we
+  // will trickle to jit::Compile() and return Method_Skipped.
+  uint32_t warmUpCount = script->getWarmUpCount();
+
+  IonCompilationId compilationId =
+      cx->runtime()->jitRuntime()->nextCompilationId();
+  JitZone* jitZone = cx->zone()->jitZone();
+  jitZone->currentCompilationIdRef().emplace(compilationId);
+  auto resetCurrentId = mozilla::MakeScopeExit(
+      [jitZone] { jitZone->currentCompilationIdRef().reset(); });
+
+  // Record constraints. If an error occured, returns false and potentially
+  // prevent future compilations. Otherwise, if an invalidation occured, then
+  // skip the current compilation.
+  bool isValid = false;
+
+  // If an inlined script is invalidated (for example, by attaching
+  // a debugger), we must also invalidate the parent IonScript.
+  if (!AddInlinedCompilations(cx, script, compilationId, snapshot, &isValid)) {
+    return false;
+  }
+  if (!isValid) {
+    return true;
+  }
+
+  // IonMonkey could have inferred better type information during
+  // compilation. Since adding the new information to the actual type
+  // information can reset the usecount, increase it back to what it was
+  // before.
+  if (warmUpCount > script->getWarmUpCount()) {
+    script->incWarmUpCounter(warmUpCount - script->getWarmUpCount());
+  }
+
+  uint32_t argumentSlots = (gen->outerInfo().nargs() + 1) * sizeof(Value);
+  uint32_t scriptFrameSize =
+      frameClass_ == FrameSizeClass::None()
+          ? frameDepth_
+          : FrameSizeClass::FromDepth(frameDepth_).frameSize();
+
+  // We encode safepoints after the OSI-point offsets have been determined.
+  if (!encodeSafepoints()) {
+    return false;
+  }
+
+  size_t numNurseryObjects = snapshot->nurseryObjects().length();
+
+  IonScript* ionScript = IonScript::New(
+      cx, compilationId, graph.totalSlotCount(), argumentSlots, scriptFrameSize,
+      snapshots_.listSize(), snapshots_.RVATableSize(), recovers_.size(),
+      bailouts_.length(), graph.numConstants(), numNurseryObjects,
+      safepointIndices_.length(), osiIndices_.length(), icList_.length(),
+      runtimeData_.length(), safepoints_.size());
+  if (!ionScript) {
+    return false;
+  }
+#ifdef DEBUG
+  ionScript->setICHash(snapshot->icHash());
+#endif
+
+  auto freeIonScript = mozilla::MakeScopeExit([&ionScript] {
+    // Use js_free instead of IonScript::Destroy: the cache list is still
+    // uninitialized.
+    js_free(ionScript);
+  });
+
+  Linker linker(masm);
+  JitCode* code = linker.newCode(cx, CodeKind::Ion);
+  if (!code) {
+    return false;
+  }
+
+  // Encode native to bytecode map if profiling is enabled.
+  if (isProfilerInstrumentationEnabled()) {
+    // Generate native-to-bytecode main table.
+    if (!generateCompactNativeToBytecodeMap(cx, code)) {
+      return false;
+    }
+
+    uint8_t* ionTableAddr =
+        ((uint8_t*)nativeToBytecodeMap_) + nativeToBytecodeTableOffset_;
+    JitcodeIonTable* ionTable = (JitcodeIonTable*)ionTableAddr;
+
+    // Construct the IonEntry that will go into the global table.
+    JitcodeGlobalEntry::IonEntry entry;
+    if (!ionTable->makeIonEntry(cx, code, nativeToBytecodeScriptListLength_,
+                                nativeToBytecodeScriptList_, entry)) {
+      js_free(nativeToBytecodeScriptList_);
+      js_free(nativeToBytecodeMap_);
+      return false;
+    }
+
+    // nativeToBytecodeScriptList_ is no longer needed.
+    js_free(nativeToBytecodeScriptList_);
+
+    // Add entry to the global table.
+    JitcodeGlobalTable* globalTable =
+        cx->runtime()->jitRuntime()->getJitcodeGlobalTable();
+    if (!globalTable->addEntry(entry)) {
+      // Memory may have been allocated for the entry.
+      entry.destroy();
+      return false;
+    }
+
+    // Mark the jitcode as having a bytecode map.
+    code->setHasBytecodeMap();
+  } else {
+    // Add a dumy jitcodeGlobalTable entry.
+    JitcodeGlobalEntry::DummyEntry entry;
+    entry.init(code, code->raw(), code->rawEnd());
+
+    // Add entry to the global table.
+    JitcodeGlobalTable* globalTable =
+        cx->runtime()->jitRuntime()->getJitcodeGlobalTable();
+    if (!globalTable->addEntry(entry)) {
+      // Memory may have been allocated for the entry.
+      entry.destroy();
+      return false;
+    }
+
+    // Mark the jitcode as having a bytecode map.
+    code->setHasBytecodeMap();
+  }
+
+  ionScript->setMethod(code);
+
+  // If the Gecko Profiler is enabled, mark IonScript as having been
+  // instrumented accordingly.
+  if (isProfilerInstrumentationEnabled()) {
+    ionScript->setHasProfilingInstrumentation();
+  }
+
+  Assembler::PatchDataWithValueCheck(
+      CodeLocationLabel(code, invalidateEpilogueData_), ImmPtr(ionScript),
+      ImmPtr((void*)-1));
+
+  for (CodeOffset offset : ionScriptLabels_) {
+    Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, offset),
+                                       ImmPtr(ionScript), ImmPtr((void*)-1));
+  }
+
+  for (NurseryObjectLabel label : ionNurseryObjectLabels_) {
+    void* entry = ionScript->addressOfNurseryObject(label.nurseryIndex);
+    Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, label.offset),
+                                       ImmPtr(entry), ImmPtr((void*)-1));
+  }
+
+#ifdef JS_TRACE_LOGGING
+  bool TLFailed = false;
+
+  MOZ_ASSERT_IF(!JS::TraceLoggerSupported(), patchableTLEvents_.length() == 0);
+  for (uint32_t i = 0; i < patchableTLEvents_.length(); i++) {
+    TraceLoggerEvent event(patchableTLEvents_[i].event);
+    if (!event.hasTextId() || !ionScript->addTraceLoggerEvent(event)) {
+      TLFailed = true;
+      break;
+    }
+    Assembler::PatchDataWithValueCheck(
+        CodeLocationLabel(code, patchableTLEvents_[i].offset),
+        ImmPtr((void*)uintptr_t(event.textId())), ImmPtr((void*)0));
+  }
+
+  if (!TLFailed && patchableTLScripts_.length() > 0) {
+    MOZ_ASSERT(TraceLogTextIdEnabled(TraceLogger_Scripts));
+    TraceLoggerEvent event(TraceLogger_Scripts, script);
+    if (!event.hasTextId() || !ionScript->addTraceLoggerEvent(event)) {
+      TLFailed = true;
+    }
+    if (!TLFailed) {
+      uint32_t textId = event.textId();
+      for (uint32_t i = 0; i < patchableTLScripts_.length(); i++) {
+        Assembler::PatchDataWithValueCheck(
+            CodeLocationLabel(code, patchableTLScripts_[i]),
+            ImmPtr((void*)uintptr_t(textId)), ImmPtr((void*)0));
+      }
+    }
+  }
+#endif
+
+  // for generating inline caches during the execution.
+  if (runtimeData_.length()) {
+    ionScript->copyRuntimeData(&runtimeData_[0]);
+  }
+  if (icList_.length()) {
+    ionScript->copyICEntries(&icList_[0]);
+  }
+
+  for (size_t i = 0; i < icInfo_.length(); i++) {
+    IonIC& ic = ionScript->getICFromIndex(i);
+    Assembler::PatchDataWithValueCheck(
+        CodeLocationLabel(code, icInfo_[i].icOffsetForJump),
+        ImmPtr(ic.codeRawPtr()), ImmPtr((void*)-1));
+    Assembler::PatchDataWithValueCheck(
+        CodeLocationLabel(code, icInfo_[i].icOffsetForPush), ImmPtr(&ic),
+        ImmPtr((void*)-1));
+  }
+
+  JitSpew(JitSpew_Codegen, "Created IonScript %p (raw %p)", (void*)ionScript,
+          (void*)code->raw());
+
+  ionScript->setInvalidationEpilogueDataOffset(
+      invalidateEpilogueData_.offset());
+  if (jsbytecode* osrPc = gen->outerInfo().osrPc()) {
+    ionScript->setOsrPc(osrPc);
+    ionScript->setOsrEntryOffset(getOsrEntryOffset());
+  }
+  ionScript->setInvalidationEpilogueOffset(invalidate_.offset());
+
+#if defined(JS_ION_PERF)
+  if (PerfEnabled()) {
+    perfSpewer_.writeProfile(script, code, masm);
+  }
+#endif
+
+#ifdef MOZ_VTUNE
+  vtune::MarkScript(code, script, "ion");
+#endif
+
+  // for marking during GC.
+  if (safepointIndices_.length()) {
+    ionScript->copySafepointIndices(&safepointIndices_[0]);
+  }
+  if (safepoints_.size()) {
+    ionScript->copySafepoints(&safepoints_);
+  }
+
+  // for reconvering from an Ion Frame.
+  if (bailouts_.length()) {
+    ionScript->copyBailoutTable(&bailouts_[0]);
+  }
+  if (osiIndices_.length()) {
+    ionScript->copyOsiIndices(&osiIndices_[0]);
+  }
+  if (snapshots_.listSize()) {
+    ionScript->copySnapshots(&snapshots_);
+  }
+  MOZ_ASSERT_IF(snapshots_.listSize(), recovers_.size());
+  if (recovers_.size()) {
+    ionScript->copyRecovers(&recovers_);
+  }
+  if (graph.numConstants()) {
+    const Value* vp = graph.constantPool();
+    ionScript->copyConstants(vp);
+    for (size_t i = 0; i < graph.numConstants(); i++) {
+      const Value& v = vp[i];
+      if (v.isGCThing()) {
+        if (gc::StoreBuffer* sb = v.toGCThing()->storeBuffer()) {
+          sb->putWholeCell(script);
+          break;
+        }
+      }
+    }
+  }
+
+  // Attach any generated script counts to the script.
+  if (IonScriptCounts* counts = extractScriptCounts()) {
+    script->addIonCounts(counts);
+  }
+
+  // WARNING: Code after this point must be infallible!
+
+  // Copy the list of nursery objects. Note that the store buffer can add
+  // HeapPtr edges that must be cleared in IonScript::Destroy. See the
+  // infallibility warning above.
+  const auto& nurseryObjects = snapshot->nurseryObjects();
+  for (size_t i = 0; i < nurseryObjects.length(); i++) {
+    ionScript->nurseryObjects()[i].init(nurseryObjects[i]);
+  }
+
+  // Transfer ownership of the IonScript to the JitScript. At this point enough
+  // of the IonScript must be initialized for IonScript::Destroy to work.
+  freeIonScript.release();
+  script->jitScript()->setIonScript(script, ionScript);
+
+  return true;
+}
+
+// An out-of-line path to convert a boxed int32 to either a float or double.
+class OutOfLineUnboxFloatingPoint : public OutOfLineCodeBase<CodeGenerator> {
+  LUnboxFloatingPoint* unboxFloatingPoint_;
+
+ public:
+  explicit OutOfLineUnboxFloatingPoint(LUnboxFloatingPoint* unboxFloatingPoint)
+      : unboxFloatingPoint_(unboxFloatingPoint) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineUnboxFloatingPoint(this);
+  }
+
+  LUnboxFloatingPoint* unboxFloatingPoint() const {
+    return unboxFloatingPoint_;
+  }
+};
+
+void CodeGenerator::visitUnboxFloatingPoint(LUnboxFloatingPoint* lir) {
+  const ValueOperand box = ToValue(lir, LUnboxFloatingPoint::Input);
+  const LDefinition* result = lir->output();
+
+  // Out-of-line path to convert int32 to double or bailout
+  // if this instruction is fallible.
+  OutOfLineUnboxFloatingPoint* ool =
+      new (alloc()) OutOfLineUnboxFloatingPoint(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  FloatRegister resultReg = ToFloatRegister(result);
+  masm.branchTestDouble(Assembler::NotEqual, box, ool->entry());
+  masm.unboxDouble(box, resultReg);
+  if (lir->type() == MIRType::Float32) {
+    masm.convertDoubleToFloat32(resultReg, resultReg);
+  }
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineUnboxFloatingPoint(
+    OutOfLineUnboxFloatingPoint* ool) {
+  LUnboxFloatingPoint* ins = ool->unboxFloatingPoint();
+  const ValueOperand value = ToValue(ins, LUnboxFloatingPoint::Input);
+
+  if (ins->mir()->fallible()) {
+    Label bail;
+    masm.branchTestInt32(Assembler::NotEqual, value, &bail);
+    bailoutFrom(&bail, ins->snapshot());
+  }
+  masm.int32ValueToFloatingPoint(value, ToFloatRegister(ins->output()),
+                                 ins->type());
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitCallBindVar(LCallBindVar* lir) {
+  pushArg(ToRegister(lir->environmentChain()));
+
+  using Fn = JSObject* (*)(JSContext*, JSObject*);
+  callVM<Fn, BindVarOperation>(lir);
+}
+
+void CodeGenerator::visitCallSetElement(LCallSetElement* lir) {
+  Register obj = ToRegister(lir->getOperand(0));
+  pushArg(Imm32(lir->mir()->strict()));
+  pushArg(TypedOrValueRegister(MIRType::Object, AnyRegister(obj)));
+  pushArg(ToValue(lir, LCallSetElement::Value));
+  pushArg(ToValue(lir, LCallSetElement::Index));
+  pushArg(obj);
+
+  using Fn = bool (*)(JSContext*, HandleObject, HandleValue, HandleValue,
+                      HandleValue, bool);
+  callVM<Fn, js::SetObjectElementWithReceiver>(lir);
+}
+
+void CodeGenerator::visitLoadFixedSlotV(LLoadFixedSlotV* ins) {
+  const Register obj = ToRegister(ins->getOperand(0));
+  size_t slot = ins->mir()->slot();
+  ValueOperand result = ToOutValue(ins);
+
+  masm.loadValue(Address(obj, NativeObject::getFixedSlotOffset(slot)), result);
+}
+
+void CodeGenerator::visitLoadFixedSlotT(LLoadFixedSlotT* ins) {
+  const Register obj = ToRegister(ins->getOperand(0));
+  size_t slot = ins->mir()->slot();
+  AnyRegister result = ToAnyRegister(ins->getDef(0));
+  MIRType type = ins->mir()->type();
+
+  masm.loadUnboxedValue(Address(obj, NativeObject::getFixedSlotOffset(slot)),
+                        type, result);
+}
+
+template <typename T>
+static void EmitLoadAndUnbox(MacroAssembler& masm, const T& src, MIRType type,
+                             bool fallible, AnyRegister dest, Label* fail) {
+  if (type == MIRType::Double) {
+    MOZ_ASSERT(dest.isFloat());
+    masm.ensureDouble(src, dest.fpu(), fail);
+    return;
+  }
+  if (fallible) {
+    switch (type) {
+      case MIRType::Int32:
+        masm.fallibleUnboxInt32(src, dest.gpr(), fail);
+        break;
+      case MIRType::Boolean:
+        masm.fallibleUnboxBoolean(src, dest.gpr(), fail);
+        break;
+      case MIRType::Object:
+        masm.fallibleUnboxObject(src, dest.gpr(), fail);
+        break;
+      case MIRType::String:
+        masm.fallibleUnboxString(src, dest.gpr(), fail);
+        break;
+      case MIRType::Symbol:
+        masm.fallibleUnboxSymbol(src, dest.gpr(), fail);
+        break;
+      case MIRType::BigInt:
+        masm.fallibleUnboxBigInt(src, dest.gpr(), fail);
+        break;
+      default:
+        MOZ_CRASH("Unexpected MIRType");
+    }
+    return;
+  }
+  masm.loadUnboxedValue(src, type, dest);
+}
+
+void CodeGenerator::visitLoadFixedSlotAndUnbox(LLoadFixedSlotAndUnbox* ins) {
+  const MLoadFixedSlotAndUnbox* mir = ins->mir();
+  MIRType type = mir->type();
+  Register input = ToRegister(ins->object());
+  AnyRegister result = ToAnyRegister(ins->output());
+  size_t slot = mir->slot();
+
+  Address address(input, NativeObject::getFixedSlotOffset(slot));
+
+  Label bail;
+  EmitLoadAndUnbox(masm, address, type, mir->fallible(), result, &bail);
+  if (mir->fallible()) {
+    bailoutFrom(&bail, ins->snapshot());
+  }
+}
+
+void CodeGenerator::visitLoadDynamicSlotAndUnbox(
+    LLoadDynamicSlotAndUnbox* ins) {
+  const MLoadDynamicSlotAndUnbox* mir = ins->mir();
+  MIRType type = mir->type();
+  Register input = ToRegister(ins->slots());
+  AnyRegister result = ToAnyRegister(ins->output());
+  size_t slot = mir->slot();
+
+  Address address(input, slot * sizeof(JS::Value));
+
+  Label bail;
+  EmitLoadAndUnbox(masm, address, type, mir->fallible(), result, &bail);
+  if (mir->fallible()) {
+    bailoutFrom(&bail, ins->snapshot());
+  }
+}
+
+void CodeGenerator::visitLoadElementAndUnbox(LLoadElementAndUnbox* ins) {
+  const MLoadElementAndUnbox* mir = ins->mir();
+  MIRType type = mir->type();
+  Register elements = ToRegister(ins->elements());
+  AnyRegister result = ToAnyRegister(ins->output());
+
+  Label bail;
+  if (ins->index()->isConstant()) {
+    NativeObject::elementsSizeMustNotOverflow();
+    int32_t offset = ToInt32(ins->index()) * sizeof(Value);
+    Address address(elements, offset);
+    EmitLoadAndUnbox(masm, address, type, mir->fallible(), result, &bail);
+  } else {
+    BaseObjectElementIndex address(elements, ToRegister(ins->index()));
+    EmitLoadAndUnbox(masm, address, type, mir->fallible(), result, &bail);
+  }
+
+  if (mir->fallible()) {
+    bailoutFrom(&bail, ins->snapshot());
+  }
+}
+
+void CodeGenerator::visitAddAndStoreSlot(LAddAndStoreSlot* ins) {
+  const Register obj = ToRegister(ins->getOperand(0));
+  const ValueOperand value = ToValue(ins, LAddAndStoreSlot::Value);
+  const Register maybeTemp = ToTempRegisterOrInvalid(ins->getTemp(0));
+
+  Shape* shape = ins->mir()->shape();
+  masm.storeObjShape(shape, obj, [](MacroAssembler& masm, const Address& addr) {
+    EmitPreBarrier(masm, addr, MIRType::Shape);
+  });
+
+  // Perform the store. No pre-barrier required since this is a new
+  // initialization.
+
+  uint32_t offset = ins->mir()->slotOffset();
+  if (ins->mir()->kind() == MAddAndStoreSlot::Kind::FixedSlot) {
+    Address slot(obj, offset);
+    masm.storeValue(value, slot);
+  } else {
+    masm.loadPtr(Address(obj, NativeObject::offsetOfSlots()), maybeTemp);
+    Address slot(maybeTemp, offset);
+    masm.storeValue(value, slot);
+  }
+}
+
+void CodeGenerator::visitAllocateAndStoreSlot(LAllocateAndStoreSlot* ins) {
+  const Register obj = ToRegister(ins->getOperand(0));
+  const ValueOperand value = ToValue(ins, LAllocateAndStoreSlot::Value);
+  const Register temp1 = ToRegister(ins->getTemp(0));
+  const Register temp2 = ToRegister(ins->getTemp(1));
+
+  masm.push(obj);
+  masm.pushValue(value);
+
+  using Fn = bool (*)(JSContext * cx, NativeObject * obj, uint32_t newCount);
+  masm.setupUnalignedABICall(temp1);
+  masm.loadJSContext(temp1);
+  masm.passABIArg(temp1);
+  masm.passABIArg(obj);
+  masm.move32(Imm32(ins->mir()->numNewSlots()), temp2);
+  masm.passABIArg(temp2);
+  masm.callWithABI<Fn, NativeObject::growSlotsPure>();
+  masm.storeCallBoolResult(temp1);
+
+  masm.popValue(value);
+  masm.pop(obj);
+
+  Label bail;
+  masm.branchIfFalseBool(temp1, &bail);
+  bailoutFrom(&bail, ins->snapshot());
+
+  masm.storeObjShape(ins->mir()->shape(), obj,
+                     [](MacroAssembler& masm, const Address& addr) {
+                       EmitPreBarrier(masm, addr, MIRType::Shape);
+                     });
+
+  // Perform the store. No pre-barrier required since this is a new
+  // initialization.
+  masm.loadPtr(Address(obj, NativeObject::offsetOfSlots()), temp1);
+  Address slot(temp1, ins->mir()->slotOffset());
+  masm.storeValue(value, slot);
+}
+
+void CodeGenerator::visitStoreFixedSlotV(LStoreFixedSlotV* ins) {
+  const Register obj = ToRegister(ins->getOperand(0));
+  size_t slot = ins->mir()->slot();
+
+  const ValueOperand value = ToValue(ins, LStoreFixedSlotV::Value);
+
+  Address address(obj, NativeObject::getFixedSlotOffset(slot));
+  if (ins->mir()->needsBarrier()) {
+    emitPreBarrier(address);
+  }
+
+  masm.storeValue(value, address);
+}
+
+void CodeGenerator::visitStoreFixedSlotT(LStoreFixedSlotT* ins) {
+  const Register obj = ToRegister(ins->getOperand(0));
+  size_t slot = ins->mir()->slot();
+
+  const LAllocation* value = ins->value();
+  MIRType valueType = ins->mir()->value()->type();
+
+  Address address(obj, NativeObject::getFixedSlotOffset(slot));
+  if (ins->mir()->needsBarrier()) {
+    emitPreBarrier(address);
+  }
+
+  ConstantOrRegister nvalue =
+      value->isConstant()
+          ? ConstantOrRegister(value->toConstant()->toJSValue())
+          : TypedOrValueRegister(valueType, ToAnyRegister(value));
+  masm.storeConstantOrRegister(nvalue, address);
+}
+
+void CodeGenerator::visitGetNameCache(LGetNameCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  Register envChain = ToRegister(ins->envObj());
+  ValueOperand output = ToOutValue(ins);
+  Register temp = ToRegister(ins->temp());
+
+  IonGetNameIC ic(liveRegs, envChain, output, temp);
+  addIC(ins, allocateIC(ic));
+}
+
+void CodeGenerator::addGetPropertyCache(LInstruction* ins,
+                                        LiveRegisterSet liveRegs,
+                                        TypedOrValueRegister value,
+                                        const ConstantOrRegister& id,
+                                        ValueOperand output) {
+  CacheKind kind = CacheKind::GetElem;
+  if (id.constant() && id.value().isString()) {
+    JSString* idString = id.value().toString();
+    uint32_t dummy;
+    if (idString->isAtom() && !idString->asAtom().isIndex(&dummy)) {
+      kind = CacheKind::GetProp;
+    }
+  }
+  IonGetPropertyIC cache(kind, liveRegs, value, id, output);
+  addIC(ins, allocateIC(cache));
+}
+
+void CodeGenerator::addSetPropertyCache(LInstruction* ins,
+                                        LiveRegisterSet liveRegs,
+                                        Register objReg, Register temp,
+                                        const ConstantOrRegister& id,
+                                        const ConstantOrRegister& value,
+                                        bool strict) {
+  CacheKind kind = CacheKind::SetElem;
+  if (id.constant() && id.value().isString()) {
+    JSString* idString = id.value().toString();
+    uint32_t dummy;
+    if (idString->isAtom() && !idString->asAtom().isIndex(&dummy)) {
+      kind = CacheKind::SetProp;
+    }
+  }
+  IonSetPropertyIC cache(kind, liveRegs, objReg, temp, id, value, strict);
+  addIC(ins, allocateIC(cache));
+}
+
+ConstantOrRegister CodeGenerator::toConstantOrRegister(LInstruction* lir,
+                                                       size_t n, MIRType type) {
+  if (type == MIRType::Value) {
+    return TypedOrValueRegister(ToValue(lir, n));
+  }
+
+  const LAllocation* value = lir->getOperand(n);
+  if (value->isConstant()) {
+    return ConstantOrRegister(value->toConstant()->toJSValue());
+  }
+
+  return TypedOrValueRegister(type, ToAnyRegister(value));
+}
+
+void CodeGenerator::visitGetPropertyCache(LGetPropertyCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  TypedOrValueRegister value =
+      toConstantOrRegister(ins, LGetPropertyCache::Value,
+                           ins->mir()->value()->type())
+          .reg();
+  ConstantOrRegister id = toConstantOrRegister(ins, LGetPropertyCache::Id,
+                                               ins->mir()->idval()->type());
+  ValueOperand output = ToOutValue(ins);
+  addGetPropertyCache(ins, liveRegs, value, id, output);
+}
+
+void CodeGenerator::visitGetPropSuperCache(LGetPropSuperCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  Register obj = ToRegister(ins->obj());
+  TypedOrValueRegister receiver =
+      toConstantOrRegister(ins, LGetPropSuperCache::Receiver,
+                           ins->mir()->receiver()->type())
+          .reg();
+  ConstantOrRegister id = toConstantOrRegister(ins, LGetPropSuperCache::Id,
+                                               ins->mir()->idval()->type());
+  ValueOperand output = ToOutValue(ins);
+
+  CacheKind kind = CacheKind::GetElemSuper;
+  if (id.constant() && id.value().isString()) {
+    JSString* idString = id.value().toString();
+    uint32_t dummy;
+    if (idString->isAtom() && !idString->asAtom().isIndex(&dummy)) {
+      kind = CacheKind::GetPropSuper;
+    }
+  }
+
+  IonGetPropSuperIC cache(kind, liveRegs, obj, receiver, id, output);
+  addIC(ins, allocateIC(cache));
+}
+
+void CodeGenerator::visitBindNameCache(LBindNameCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  Register envChain = ToRegister(ins->environmentChain());
+  Register output = ToRegister(ins->output());
+  Register temp = ToRegister(ins->temp());
+
+  IonBindNameIC ic(liveRegs, envChain, output, temp);
+  addIC(ins, allocateIC(ic));
+}
+
+void CodeGenerator::visitHasOwnCache(LHasOwnCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  TypedOrValueRegister value = toConstantOrRegister(ins, LHasOwnCache::Value,
+                                                    ins->mir()->value()->type())
+                                   .reg();
+  TypedOrValueRegister id =
+      toConstantOrRegister(ins, LHasOwnCache::Id, ins->mir()->idval()->type())
+          .reg();
+  Register output = ToRegister(ins->output());
+
+  IonHasOwnIC cache(liveRegs, value, id, output);
+  addIC(ins, allocateIC(cache));
+}
+
+void CodeGenerator::visitCheckPrivateFieldCache(LCheckPrivateFieldCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  TypedOrValueRegister value =
+      toConstantOrRegister(ins, LCheckPrivateFieldCache::Value,
+                           ins->mir()->value()->type())
+          .reg();
+  TypedOrValueRegister id =
+      toConstantOrRegister(ins, LCheckPrivateFieldCache::Id,
+                           ins->mir()->idval()->type())
+          .reg();
+  Register output = ToRegister(ins->output());
+
+  IonCheckPrivateFieldIC cache(liveRegs, value, id, output);
+  addIC(ins, allocateIC(cache));
+}
+
+void CodeGenerator::visitCallDeleteProperty(LCallDeleteProperty* lir) {
+  pushArg(ImmGCPtr(lir->mir()->name()));
+  pushArg(ToValue(lir, LCallDeleteProperty::Value));
+
+  using Fn = bool (*)(JSContext*, HandleValue, HandlePropertyName, bool*);
+  if (lir->mir()->strict()) {
+    callVM<Fn, DelPropOperation<true>>(lir);
+  } else {
+    callVM<Fn, DelPropOperation<false>>(lir);
+  }
+}
+
+void CodeGenerator::visitCallDeleteElement(LCallDeleteElement* lir) {
+  pushArg(ToValue(lir, LCallDeleteElement::Index));
+  pushArg(ToValue(lir, LCallDeleteElement::Value));
+
+  using Fn = bool (*)(JSContext*, HandleValue, HandleValue, bool*);
+  if (lir->mir()->strict()) {
+    callVM<Fn, DelElemOperation<true>>(lir);
+  } else {
+    callVM<Fn, DelElemOperation<false>>(lir);
+  }
+}
+
+void CodeGenerator::visitSetPropertyCache(LSetPropertyCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  Register objReg = ToRegister(ins->getOperand(0));
+  Register temp = ToRegister(ins->temp());
+
+  ConstantOrRegister id = toConstantOrRegister(ins, LSetPropertyCache::Id,
+                                               ins->mir()->idval()->type());
+  ConstantOrRegister value = toConstantOrRegister(ins, LSetPropertyCache::Value,
+                                                  ins->mir()->value()->type());
+
+  addSetPropertyCache(ins, liveRegs, objReg, temp, id, value,
+                      ins->mir()->strict());
+}
+
+void CodeGenerator::visitThrow(LThrow* lir) {
+  pushArg(ToValue(lir, LThrow::Value));
+
+  using Fn = bool (*)(JSContext*, HandleValue);
+  callVM<Fn, js::ThrowOperation>(lir);
+}
+
+class OutOfLineTypeOfV : public OutOfLineCodeBase<CodeGenerator> {
+  LTypeOfV* ins_;
+
+ public:
+  explicit OutOfLineTypeOfV(LTypeOfV* ins) : ins_(ins) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineTypeOfV(this);
+  }
+  LTypeOfV* ins() const { return ins_; }
+};
+
+void CodeGenerator::visitTypeOfV(LTypeOfV* lir) {
+  const ValueOperand value = ToValue(lir, LTypeOfV::Input);
+  Register output = ToRegister(lir->output());
+  Register tag = masm.extractTag(value, output);
+
+  const JSAtomState& names = gen->runtime->names();
+  Label done;
+
+  OutOfLineTypeOfV* ool = nullptr;
+  if (lir->mir()->inputMaybeCallableOrEmulatesUndefined()) {
+    // The input may be a callable object (result is "function") or may
+    // emulate undefined (result is "undefined"). Use an OOL path.
+    ool = new (alloc()) OutOfLineTypeOfV(lir);
+    addOutOfLineCode(ool, lir->mir());
+    masm.branchTestObject(Assembler::Equal, tag, ool->entry());
+  } else {
+    // Input is not callable and does not emulate undefined, so if
+    // it's an object the result is always "object".
+    Label notObject;
+    masm.branchTestObject(Assembler::NotEqual, tag, &notObject);
+    masm.movePtr(ImmGCPtr(names.object), output);
+    masm.jump(&done);
+    masm.bind(&notObject);
+  }
+
+  Label notNumber;
+  masm.branchTestNumber(Assembler::NotEqual, tag, &notNumber);
+  masm.movePtr(ImmGCPtr(names.number), output);
+  masm.jump(&done);
+  masm.bind(&notNumber);
+
+  Label notUndefined;
+  masm.branchTestUndefined(Assembler::NotEqual, tag, &notUndefined);
+  masm.movePtr(ImmGCPtr(names.undefined), output);
+  masm.jump(&done);
+  masm.bind(&notUndefined);
+
+  Label notNull;
+  masm.branchTestNull(Assembler::NotEqual, tag, &notNull);
+  masm.movePtr(ImmGCPtr(names.object), output);
+  masm.jump(&done);
+  masm.bind(&notNull);
+
+  Label notBoolean;
+  masm.branchTestBoolean(Assembler::NotEqual, tag, &notBoolean);
+  masm.movePtr(ImmGCPtr(names.boolean), output);
+  masm.jump(&done);
+  masm.bind(&notBoolean);
+
+  Label notString;
+  masm.branchTestString(Assembler::NotEqual, tag, &notString);
+  masm.movePtr(ImmGCPtr(names.string), output);
+  masm.jump(&done);
+  masm.bind(&notString);
+
+  Label notSymbol;
+  masm.branchTestSymbol(Assembler::NotEqual, tag, &notSymbol);
+  masm.movePtr(ImmGCPtr(names.symbol), output);
+  masm.jump(&done);
+  masm.bind(&notSymbol);
+
+  // At this point it must be a BigInt.
+#ifdef DEBUG
+  Label isBigInt;
+  masm.branchTestBigInt(Assembler::Equal, tag, &isBigInt);
+  masm.assumeUnreachable("Unexpected Value type in visitTypeOfV");
+  masm.bind(&isBigInt);
+#endif
+  masm.movePtr(ImmGCPtr(names.bigint), output);
+  // Fall through to |done|.
+
+  masm.bind(&done);
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::emitTypeOfObject(Register obj, Register output,
+                                     Label* done) {
+  const JSAtomState& names = gen->runtime->names();
+
+  Label slowCheck, isObject, isCallable, isUndefined;
+  masm.typeOfObject(obj, output, &slowCheck, &isObject, &isCallable,
+                    &isUndefined);
+
+  masm.bind(&isCallable);
+  masm.movePtr(ImmGCPtr(names.function), output);
+  masm.jump(done);
+
+  masm.bind(&isUndefined);
+  masm.movePtr(ImmGCPtr(names.undefined), output);
+  masm.jump(done);
+
+  masm.bind(&isObject);
+  masm.movePtr(ImmGCPtr(names.object), output);
+  masm.jump(done);
+
+  masm.bind(&slowCheck);
+
+  saveVolatile(output);
+  using Fn = JSString* (*)(JSObject * obj, JSRuntime * rt);
+  masm.setupUnalignedABICall(output);
+  masm.passABIArg(obj);
+  masm.movePtr(ImmPtr(gen->runtime), output);
+  masm.passABIArg(output);
+  masm.callWithABI<Fn, TypeOfObject>();
+  masm.storeCallPointerResult(output);
+  restoreVolatile(output);
+}
+
+void CodeGenerator::visitOutOfLineTypeOfV(OutOfLineTypeOfV* ool) {
+  LTypeOfV* ins = ool->ins();
+
+  ValueOperand input = ToValue(ins, LTypeOfV::Input);
+  Register temp = ToTempUnboxRegister(ins->tempToUnbox());
+  Register output = ToRegister(ins->output());
+
+  Register obj = masm.extractObject(input, temp);
+  emitTypeOfObject(obj, output, ool->rejoin());
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitTypeOfO(LTypeOfO* lir) {
+  Register obj = ToRegister(lir->object());
+  Register output = ToRegister(lir->output());
+
+  Label done;
+  emitTypeOfObject(obj, output, &done);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitToAsyncIter(LToAsyncIter* lir) {
+  pushArg(ToValue(lir, LToAsyncIter::NextMethodIndex));
+  pushArg(ToRegister(lir->iterator()));
+
+  using Fn = JSObject* (*)(JSContext*, HandleObject, HandleValue);
+  callVM<Fn, js::CreateAsyncFromSyncIterator>(lir);
+}
+
+void CodeGenerator::visitToPropertyKeyCache(LToPropertyKeyCache* lir) {
+  LiveRegisterSet liveRegs = lir->safepoint()->liveRegs();
+  ValueOperand input = ToValue(lir, LToPropertyKeyCache::Input);
+  ValueOperand output = ToOutValue(lir);
+
+  IonToPropertyKeyIC ic(liveRegs, input, output);
+  addIC(lir, allocateIC(ic));
+}
+
+void CodeGenerator::visitLoadElementV(LLoadElementV* load) {
+  Register elements = ToRegister(load->elements());
+  const ValueOperand out = ToOutValue(load);
+
+  if (load->index()->isConstant()) {
+    NativeObject::elementsSizeMustNotOverflow();
+    int32_t offset = ToInt32(load->index()) * sizeof(Value);
+    masm.loadValue(Address(elements, offset), out);
+  } else {
+    masm.loadValue(BaseObjectElementIndex(elements, ToRegister(load->index())),
+                   out);
+  }
+
+  if (load->mir()->needsHoleCheck()) {
+    Label testMagic;
+    masm.branchTestMagic(Assembler::Equal, out, &testMagic);
+    bailoutFrom(&testMagic, load->snapshot());
+  }
+}
+
+void CodeGenerator::visitLoadElementHole(LLoadElementHole* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register index = ToRegister(lir->index());
+  Register initLength = ToRegister(lir->initLength());
+  const ValueOperand out = ToOutValue(lir);
+
+  const MLoadElementHole* mir = lir->mir();
+
+  // If the index is out of bounds, load |undefined|. Otherwise, load the
+  // value.
+  Label outOfBounds, done;
+  masm.spectreBoundsCheck32(index, initLength, out.scratchReg(), &outOfBounds);
+
+  masm.loadValue(BaseObjectElementIndex(elements, index), out);
+
+  // If a hole check is needed, and the value wasn't a hole, we're done.
+  // Otherwise, we'll load undefined.
+  if (lir->mir()->needsHoleCheck()) {
+    masm.branchTestMagic(Assembler::NotEqual, out, &done);
+    masm.moveValue(UndefinedValue(), out);
+  }
+  masm.jump(&done);
+
+  masm.bind(&outOfBounds);
+  if (mir->needsNegativeIntCheck()) {
+    Label negative;
+    masm.branch32(Assembler::LessThan, index, Imm32(0), &negative);
+    bailoutFrom(&negative, lir->snapshot());
+  }
+  masm.moveValue(UndefinedValue(), out);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitLoadUnboxedScalar(LLoadUnboxedScalar* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register temp = ToTempRegisterOrInvalid(lir->temp());
+  AnyRegister out = ToAnyRegister(lir->output());
+
+  const MLoadUnboxedScalar* mir = lir->mir();
+
+  Scalar::Type storageType = mir->storageType();
+  size_t width = Scalar::byteSize(storageType);
+
+  Label fail;
+  if (lir->index()->isConstant()) {
+    Address source(elements,
+                   ToInt32(lir->index()) * width + mir->offsetAdjustment());
+    masm.loadFromTypedArray(storageType, source, out, temp, &fail);
+  } else {
+    BaseIndex source(elements, ToRegister(lir->index()),
+                     ScaleFromElemWidth(width), mir->offsetAdjustment());
+    masm.loadFromTypedArray(storageType, source, out, temp, &fail);
+  }
+
+  if (fail.used()) {
+    bailoutFrom(&fail, lir->snapshot());
+  }
+}
+
+void CodeGenerator::visitLoadUnboxedBigInt(LLoadUnboxedBigInt* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register temp = ToRegister(lir->temp());
+  Register64 temp64 = ToRegister64(lir->temp64());
+  Register out = ToRegister(lir->output());
+
+  const MLoadUnboxedScalar* mir = lir->mir();
+
+  Scalar::Type storageType = mir->storageType();
+  size_t width = Scalar::byteSize(storageType);
+
+  if (lir->index()->isConstant()) {
+    Address source(elements,
+                   ToInt32(lir->index()) * width + mir->offsetAdjustment());
+    masm.load64(source, temp64);
+  } else {
+    BaseIndex source(elements, ToRegister(lir->index()),
+                     ScaleFromElemWidth(width), mir->offsetAdjustment());
+    masm.load64(source, temp64);
+  }
+
+  emitCreateBigInt(lir, storageType, temp64, out, temp);
+}
+
+void CodeGenerator::visitLoadDataViewElement(LLoadDataViewElement* lir) {
+  Register elements = ToRegister(lir->elements());
+  const LAllocation* littleEndian = lir->littleEndian();
+  Register temp = ToTempRegisterOrInvalid(lir->temp());
+  Register64 temp64 = ToTempRegister64OrInvalid(lir->temp64());
+  AnyRegister out = ToAnyRegister(lir->output());
+
+  const MLoadDataViewElement* mir = lir->mir();
+  Scalar::Type storageType = mir->storageType();
+
+  BaseIndex source(elements, ToRegister(lir->index()), TimesOne);
+
+  bool noSwap = littleEndian->isConstant() &&
+                ToBoolean(littleEndian) == MOZ_LITTLE_ENDIAN();
+
+  // Directly load if no byte swap is needed and the platform supports unaligned
+  // accesses for floating point registers.
+  if (noSwap && MacroAssembler::SupportsFastUnalignedAccesses()) {
+    if (!Scalar::isBigIntType(storageType)) {
+      Label fail;
+      masm.loadFromTypedArray(storageType, source, out, temp, &fail);
+
+      if (fail.used()) {
+        bailoutFrom(&fail, lir->snapshot());
+      }
+    } else {
+      masm.load64(source, temp64);
+
+      emitCreateBigInt(lir, storageType, temp64, out.gpr(), temp);
+    }
+    return;
+  }
+
+  // Load the value into a gpr register.
+  switch (storageType) {
+    case Scalar::Int16:
+      masm.load16UnalignedSignExtend(source, out.gpr());
+      break;
+    case Scalar::Uint16:
+      masm.load16UnalignedZeroExtend(source, out.gpr());
+      break;
+    case Scalar::Int32:
+      masm.load32Unaligned(source, out.gpr());
+      break;
+    case Scalar::Uint32:
+      masm.load32Unaligned(source, out.isFloat() ? temp : out.gpr());
+      break;
+    case Scalar::Float32:
+      masm.load32Unaligned(source, temp);
+      break;
+    case Scalar::Float64:
+    case Scalar::BigInt64:
+    case Scalar::BigUint64:
+      masm.load64Unaligned(source, temp64);
+      break;
+    case Scalar::Int8:
+    case Scalar::Uint8:
+    case Scalar::Uint8Clamped:
+    default:
+      MOZ_CRASH("Invalid typed array type");
+  }
+
+  if (!noSwap) {
+    // Swap the bytes in the loaded value.
+    Label skip;
+    if (!littleEndian->isConstant()) {
+      masm.branch32(
+          MOZ_LITTLE_ENDIAN() ? Assembler::NotEqual : Assembler::Equal,
+          ToRegister(littleEndian), Imm32(0), &skip);
+    }
+
+    switch (storageType) {
+      case Scalar::Int16:
+        masm.byteSwap16SignExtend(out.gpr());
+        break;
+      case Scalar::Uint16:
+        masm.byteSwap16ZeroExtend(out.gpr());
+        break;
+      case Scalar::Int32:
+        masm.byteSwap32(out.gpr());
+        break;
+      case Scalar::Uint32:
+        masm.byteSwap32(out.isFloat() ? temp : out.gpr());
+        break;
+      case Scalar::Float32:
+        masm.byteSwap32(temp);
+        break;
+      case Scalar::Float64:
+      case Scalar::BigInt64:
+      case Scalar::BigUint64:
+        masm.byteSwap64(temp64);
+        break;
+      case Scalar::Int8:
+      case Scalar::Uint8:
+      case Scalar::Uint8Clamped:
+      default:
+        MOZ_CRASH("Invalid typed array type");
+    }
+
+    if (skip.used()) {
+      masm.bind(&skip);
+    }
+  }
+
+  // Move the value into the output register.
+  switch (storageType) {
+    case Scalar::Int16:
+    case Scalar::Uint16:
+    case Scalar::Int32:
+      break;
+    case Scalar::Uint32:
+      if (out.isFloat()) {
+        masm.convertUInt32ToDouble(temp, out.fpu());
+      } else {
+        // Bail out if the value doesn't fit into a signed int32 value. This
+        // is what allows MLoadDataViewElement to have a type() of
+        // MIRType::Int32 for UInt32 array loads.
+        bailoutTest32(Assembler::Signed, out.gpr(), out.gpr(), lir->snapshot());
+      }
+      break;
+    case Scalar::Float32:
+      masm.moveGPRToFloat32(temp, out.fpu());
+      masm.canonicalizeFloat(out.fpu());
+      break;
+    case Scalar::Float64:
+      masm.moveGPR64ToDouble(temp64, out.fpu());
+      masm.canonicalizeDouble(out.fpu());
+      break;
+    case Scalar::BigInt64:
+    case Scalar::BigUint64:
+      emitCreateBigInt(lir, storageType, temp64, out.gpr(), temp);
+      break;
+    case Scalar::Int8:
+    case Scalar::Uint8:
+    case Scalar::Uint8Clamped:
+    default:
+      MOZ_CRASH("Invalid typed array type");
+  }
+}
+
+void CodeGenerator::visitLoadTypedArrayElementHole(
+    LLoadTypedArrayElementHole* lir) {
+  Register object = ToRegister(lir->object());
+  const ValueOperand out = ToOutValue(lir);
+
+  // Load the length.
+  Register scratch = out.scratchReg();
+  Register scratch2 = ToRegister(lir->temp());
+  Register index = ToRegister(lir->index());
+  masm.loadArrayBufferViewLengthInt32(object, scratch);
+
+  // Load undefined if index >= length.
+  Label outOfBounds, done;
+  masm.spectreBoundsCheck32(index, scratch, scratch2, &outOfBounds);
+
+  // Load the elements vector.
+  masm.loadPtr(Address(object, ArrayBufferViewObject::dataOffset()), scratch);
+
+  Scalar::Type arrayType = lir->mir()->arrayType();
+  size_t width = Scalar::byteSize(arrayType);
+  Label fail;
+  BaseIndex source(scratch, index, ScaleFromElemWidth(width));
+  masm.loadFromTypedArray(arrayType, source, out, lir->mir()->allowDouble(),
+                          out.scratchReg(), &fail);
+  masm.jump(&done);
+
+  masm.bind(&outOfBounds);
+  masm.moveValue(UndefinedValue(), out);
+
+  if (fail.used()) {
+    bailoutFrom(&fail, lir->snapshot());
+  }
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitLoadTypedArrayElementHoleBigInt(
+    LLoadTypedArrayElementHoleBigInt* lir) {
+  Register object = ToRegister(lir->object());
+  const ValueOperand out = ToOutValue(lir);
+
+  // On x86 there are not enough registers. In that case reuse the output's
+  // type register as temporary.
+#ifdef JS_CODEGEN_X86
+  MOZ_ASSERT(lir->temp()->isBogusTemp());
+  Register temp = out.typeReg();
+#else
+  Register temp = ToRegister(lir->temp());
+#endif
+  Register64 temp64 = ToRegister64(lir->temp64());
+
+  // Load the length.
+  Register scratch = out.scratchReg();
+  Register index = ToRegister(lir->index());
+  masm.loadArrayBufferViewLengthInt32(object, scratch);
+
+  // Load undefined if index >= length.
+  Label outOfBounds, done;
+  masm.spectreBoundsCheck32(index, scratch, temp, &outOfBounds);
+
+  // Load the elements vector.
+  masm.loadPtr(Address(object, ArrayBufferViewObject::dataOffset()), scratch);
+
+  Scalar::Type arrayType = lir->mir()->arrayType();
+  size_t width = Scalar::byteSize(arrayType);
+  BaseIndex source(scratch, index, ScaleFromElemWidth(width));
+  masm.load64(source, temp64);
+
+  Register bigInt = out.scratchReg();
+  emitCreateBigInt(lir, arrayType, temp64, bigInt, temp);
+
+  masm.tagValue(JSVAL_TYPE_BIGINT, bigInt, out);
+  masm.jump(&done);
+
+  masm.bind(&outOfBounds);
+  masm.moveValue(UndefinedValue(), out);
+
+  masm.bind(&done);
+}
+
+template <SwitchTableType tableType>
+class OutOfLineSwitch : public OutOfLineCodeBase<CodeGenerator> {
+  using LabelsVector = Vector<Label, 0, JitAllocPolicy>;
+  using CodeLabelsVector = Vector<CodeLabel, 0, JitAllocPolicy>;
+  LabelsVector labels_;
+  CodeLabelsVector codeLabels_;
+  CodeLabel start_;
+  bool isOutOfLine_;
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineSwitch(this);
+  }
+
+ public:
+  explicit OutOfLineSwitch(TempAllocator& alloc)
+      : labels_(alloc), codeLabels_(alloc), isOutOfLine_(false) {}
+
+  CodeLabel* start() { return &start_; }
+
+  CodeLabelsVector& codeLabels() { return codeLabels_; }
+  LabelsVector& labels() { return labels_; }
+
+  void jumpToCodeEntries(MacroAssembler& masm, Register index, Register temp) {
+    Register base;
+    if (tableType == SwitchTableType::Inline) {
+#if defined(JS_CODEGEN_ARM)
+      base = ::js::jit::pc;
+#else
+      MOZ_CRASH("NYI: SwitchTableType::Inline");
+#endif
+    } else {
+#if defined(JS_CODEGEN_ARM)
+      MOZ_CRASH("NYI: SwitchTableType::OutOfLine");
+#else
+      masm.mov(start(), temp);
+      base = temp;
+#endif
+    }
+    BaseIndex jumpTarget(base, index, ScalePointer);
+    masm.branchToComputedAddress(jumpTarget);
+  }
+
+  // Register an entry in the switch table.
+  void addTableEntry(MacroAssembler& masm) {
+    if ((!isOutOfLine_ && tableType == SwitchTableType::Inline) ||
+        (isOutOfLine_ && tableType == SwitchTableType::OutOfLine)) {
+      CodeLabel cl;
+      masm.writeCodePointer(&cl);
+      masm.propagateOOM(codeLabels_.append(std::move(cl)));
+    }
+  }
+  // Register the code, to which the table will jump to.
+  void addCodeEntry(MacroAssembler& masm) {
+    Label entry;
+    masm.bind(&entry);
+    masm.propagateOOM(labels_.append(std::move(entry)));
+  }
+
+  void setOutOfLine() { isOutOfLine_ = true; }
+};
+
+template <SwitchTableType tableType>
+void CodeGenerator::visitOutOfLineSwitch(
+    OutOfLineSwitch<tableType>* jumpTable) {
+  jumpTable->setOutOfLine();
+  auto& labels = jumpTable->labels();
+
+  if (tableType == SwitchTableType::OutOfLine) {
+#if defined(JS_CODEGEN_ARM)
+    MOZ_CRASH("NYI: SwitchTableType::OutOfLine");
+#elif defined(JS_CODEGEN_NONE)
+    MOZ_CRASH();
+#else
+
+#  if defined(JS_CODEGEN_ARM64)
+    AutoForbidPoolsAndNops afp(
+        &masm,
+        (labels.length() + 1) * (sizeof(void*) / vixl::kInstructionSize));
+#  endif
+
+    masm.haltingAlign(sizeof(void*));
+
+    // Bind the address of the jump table and reserve the space for code
+    // pointers to jump in the newly generated code.
+    masm.bind(jumpTable->start());
+    masm.addCodeLabel(*jumpTable->start());
+    for (size_t i = 0, e = labels.length(); i < e; i++) {
+      jumpTable->addTableEntry(masm);
+    }
+#endif
+  }
+
+  // Register all reserved pointers of the jump table to target labels. The
+  // entries of the jump table need to be absolute addresses and thus must be
+  // patched after codegen is finished.
+  auto& codeLabels = jumpTable->codeLabels();
+  for (size_t i = 0, e = codeLabels.length(); i < e; i++) {
+    auto& cl = codeLabels[i];
+    cl.target()->bind(labels[i].offset());
+    masm.addCodeLabel(cl);
+  }
+}
+
+template void CodeGenerator::visitOutOfLineSwitch(
+    OutOfLineSwitch<SwitchTableType::Inline>* jumpTable);
+template void CodeGenerator::visitOutOfLineSwitch(
+    OutOfLineSwitch<SwitchTableType::OutOfLine>* jumpTable);
+
+template <typename T>
+static inline void StoreToTypedArray(MacroAssembler& masm,
+                                     Scalar::Type writeType,
+                                     const LAllocation* value, const T& dest) {
+  if (writeType == Scalar::Float32 || writeType == Scalar::Float64) {
+    masm.storeToTypedFloatArray(writeType, ToFloatRegister(value), dest);
+  } else {
+    if (value->isConstant()) {
+      masm.storeToTypedIntArray(writeType, Imm32(ToInt32(value)), dest);
+    } else {
+      masm.storeToTypedIntArray(writeType, ToRegister(value), dest);
+    }
+  }
+}
+
+void CodeGenerator::visitStoreUnboxedScalar(LStoreUnboxedScalar* lir) {
+  Register elements = ToRegister(lir->elements());
+  const LAllocation* value = lir->value();
+
+  const MStoreUnboxedScalar* mir = lir->mir();
+
+  Scalar::Type writeType = mir->writeType();
+
+  size_t width = Scalar::byteSize(mir->writeType());
+
+  if (lir->index()->isConstant()) {
+    Address dest(elements, ToInt32(lir->index()) * width);
+    StoreToTypedArray(masm, writeType, value, dest);
+  } else {
+    BaseIndex dest(elements, ToRegister(lir->index()),
+                   ScaleFromElemWidth(width));
+    StoreToTypedArray(masm, writeType, value, dest);
+  }
+}
+
+void CodeGenerator::visitStoreUnboxedBigInt(LStoreUnboxedBigInt* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register value = ToRegister(lir->value());
+  Register64 temp = ToRegister64(lir->temp());
+
+  const MStoreUnboxedScalar* mir = lir->mir();
+  Scalar::Type writeType = mir->writeType();
+  size_t width = Scalar::byteSize(mir->writeType());
+
+  masm.loadBigInt64(value, temp);
+
+  if (lir->index()->isConstant()) {
+    Address dest(elements, ToInt32(lir->index()) * width);
+    masm.storeToTypedBigIntArray(writeType, temp, dest);
+  } else {
+    BaseIndex dest(elements, ToRegister(lir->index()),
+                   ScaleFromElemWidth(width));
+    masm.storeToTypedBigIntArray(writeType, temp, dest);
+  }
+}
+
+void CodeGenerator::visitStoreDataViewElement(LStoreDataViewElement* lir) {
+  Register elements = ToRegister(lir->elements());
+  const LAllocation* value = lir->value();
+  const LAllocation* littleEndian = lir->littleEndian();
+  Register temp = ToTempRegisterOrInvalid(lir->temp());
+  Register64 temp64 = ToTempRegister64OrInvalid(lir->temp64());
+
+  const MStoreDataViewElement* mir = lir->mir();
+  Scalar::Type writeType = mir->writeType();
+
+  BaseIndex dest(elements, ToRegister(lir->index()), TimesOne);
+
+  bool noSwap = littleEndian->isConstant() &&
+                ToBoolean(littleEndian) == MOZ_LITTLE_ENDIAN();
+
+  // Directly store if no byte swap is needed and the platform supports
+  // unaligned accesses for floating point registers.
+  if (noSwap && MacroAssembler::SupportsFastUnalignedAccesses()) {
+    if (!Scalar::isBigIntType(writeType)) {
+      StoreToTypedArray(masm, writeType, value, dest);
+    } else {
+      masm.loadBigInt64(ToRegister(value), temp64);
+      masm.storeToTypedBigIntArray(writeType, temp64, dest);
+    }
+    return;
+  }
+
+  // Load the value into a gpr register.
+  switch (writeType) {
+    case Scalar::Int16:
+    case Scalar::Uint16:
+    case Scalar::Int32:
+    case Scalar::Uint32:
+      if (value->isConstant()) {
+        masm.move32(Imm32(ToInt32(value)), temp);
+      } else {
+        masm.move32(ToRegister(value), temp);
+      }
+      break;
+    case Scalar::Float32: {
+      FloatRegister fvalue = ToFloatRegister(value);
+      masm.canonicalizeFloatIfDeterministic(fvalue);
+      masm.moveFloat32ToGPR(fvalue, temp);
+      break;
+    }
+    case Scalar::Float64: {
+      FloatRegister fvalue = ToFloatRegister(value);
+      masm.canonicalizeDoubleIfDeterministic(fvalue);
+      masm.moveDoubleToGPR64(fvalue, temp64);
+      break;
+    }
+    case Scalar::BigInt64:
+    case Scalar::BigUint64:
+      masm.loadBigInt64(ToRegister(value), temp64);
+      break;
+    case Scalar::Int8:
+    case Scalar::Uint8:
+    case Scalar::Uint8Clamped:
+    default:
+      MOZ_CRASH("Invalid typed array type");
+  }
+
+  if (!noSwap) {
+    // Swap the bytes in the loaded value.
+    Label skip;
+    if (!littleEndian->isConstant()) {
+      masm.branch32(
+          MOZ_LITTLE_ENDIAN() ? Assembler::NotEqual : Assembler::Equal,
+          ToRegister(littleEndian), Imm32(0), &skip);
+    }
+
+    switch (writeType) {
+      case Scalar::Int16:
+        masm.byteSwap16SignExtend(temp);
+        break;
+      case Scalar::Uint16:
+        masm.byteSwap16ZeroExtend(temp);
+        break;
+      case Scalar::Int32:
+      case Scalar::Uint32:
+      case Scalar::Float32:
+        masm.byteSwap32(temp);
+        break;
+      case Scalar::Float64:
+      case Scalar::BigInt64:
+      case Scalar::BigUint64:
+        masm.byteSwap64(temp64);
+        break;
+      case Scalar::Int8:
+      case Scalar::Uint8:
+      case Scalar::Uint8Clamped:
+      default:
+        MOZ_CRASH("Invalid typed array type");
+    }
+
+    if (skip.used()) {
+      masm.bind(&skip);
+    }
+  }
+
+  // Store the value into the destination.
+  switch (writeType) {
+    case Scalar::Int16:
+    case Scalar::Uint16:
+      masm.store16Unaligned(temp, dest);
+      break;
+    case Scalar::Int32:
+    case Scalar::Uint32:
+    case Scalar::Float32:
+      masm.store32Unaligned(temp, dest);
+      break;
+    case Scalar::Float64:
+    case Scalar::BigInt64:
+    case Scalar::BigUint64:
+      masm.store64Unaligned(temp64, dest);
+      break;
+    case Scalar::Int8:
+    case Scalar::Uint8:
+    case Scalar::Uint8Clamped:
+    default:
+      MOZ_CRASH("Invalid typed array type");
+  }
+}
+
+void CodeGenerator::visitStoreTypedArrayElementHole(
+    LStoreTypedArrayElementHole* lir) {
+  Register elements = ToRegister(lir->elements());
+  const LAllocation* value = lir->value();
+
+  Scalar::Type arrayType = lir->mir()->arrayType();
+  size_t width = Scalar::byteSize(arrayType);
+
+  Register index = ToRegister(lir->index());
+  const LAllocation* length = lir->length();
+  Register spectreTemp = ToTempRegisterOrInvalid(lir->spectreTemp());
+
+  Label skip;
+  if (length->isRegister()) {
+    masm.spectreBoundsCheck32(index, ToRegister(length), spectreTemp, &skip);
+  } else {
+    masm.spectreBoundsCheck32(index, ToAddress(length), spectreTemp, &skip);
+  }
+
+  BaseIndex dest(elements, index, ScaleFromElemWidth(width));
+  StoreToTypedArray(masm, arrayType, value, dest);
+
+  masm.bind(&skip);
+}
+
+void CodeGenerator::visitStoreTypedArrayElementHoleBigInt(
+    LStoreTypedArrayElementHoleBigInt* lir) {
+  Register elements = ToRegister(lir->elements());
+  Register value = ToRegister(lir->value());
+  Register64 temp = ToRegister64(lir->temp());
+
+  Scalar::Type arrayType = lir->mir()->arrayType();
+  size_t width = Scalar::byteSize(arrayType);
+
+  Register index = ToRegister(lir->index());
+  const LAllocation* length = lir->length();
+  Register spectreTemp = temp.scratchReg();
+
+  Label skip;
+  if (length->isRegister()) {
+    masm.spectreBoundsCheck32(index, ToRegister(length), spectreTemp, &skip);
+  } else {
+    masm.spectreBoundsCheck32(index, ToAddress(length), spectreTemp, &skip);
+  }
+
+  masm.loadBigInt64(value, temp);
+
+  BaseIndex dest(elements, index, ScaleFromElemWidth(width));
+  masm.storeToTypedBigIntArray(arrayType, temp, dest);
+
+  masm.bind(&skip);
+}
+
+void CodeGenerator::visitAtomicIsLockFree(LAtomicIsLockFree* lir) {
+  Register value = ToRegister(lir->value());
+  Register output = ToRegister(lir->output());
+
+  masm.atomicIsLockFreeJS(value, output);
+}
+
+void CodeGenerator::visitClampIToUint8(LClampIToUint8* lir) {
+  Register output = ToRegister(lir->output());
+  MOZ_ASSERT(output == ToRegister(lir->input()));
+  masm.clampIntToUint8(output);
+}
+
+void CodeGenerator::visitClampDToUint8(LClampDToUint8* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+  Register output = ToRegister(lir->output());
+  masm.clampDoubleToUint8(input, output);
+}
+
+void CodeGenerator::visitClampVToUint8(LClampVToUint8* lir) {
+  ValueOperand operand = ToValue(lir, LClampVToUint8::Input);
+  FloatRegister tempFloat = ToFloatRegister(lir->tempFloat());
+  Register output = ToRegister(lir->output());
+
+  using Fn = bool (*)(JSContext*, JSString*, double*);
+  OutOfLineCode* oolString = oolCallVM<Fn, StringToNumber>(
+      lir, ArgList(output), StoreFloatRegisterTo(tempFloat));
+  Label* stringEntry = oolString->entry();
+  Label* stringRejoin = oolString->rejoin();
+
+  Label fails;
+  masm.clampValueToUint8(operand, stringEntry, stringRejoin, output, tempFloat,
+                         output, &fails);
+
+  bailoutFrom(&fails, lir->snapshot());
+}
+
+void CodeGenerator::visitInCache(LInCache* ins) {
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+
+  ConstantOrRegister key =
+      toConstantOrRegister(ins, LInCache::LHS, ins->mir()->key()->type());
+  Register object = ToRegister(ins->rhs());
+  Register output = ToRegister(ins->output());
+  Register temp = ToRegister(ins->temp());
+
+  IonInIC cache(liveRegs, key, object, output, temp);
+  addIC(ins, allocateIC(cache));
+}
+
+void CodeGenerator::visitInArray(LInArray* lir) {
+  const MInArray* mir = lir->mir();
+  Register elements = ToRegister(lir->elements());
+  Register initLength = ToRegister(lir->initLength());
+  Register output = ToRegister(lir->output());
+
+  Label falseBranch, done, trueBranch;
+
+  if (lir->index()->isConstant()) {
+    int32_t index = ToInt32(lir->index());
+
+    if (index < 0) {
+      MOZ_ASSERT(mir->needsNegativeIntCheck());
+      bailout(lir->snapshot());
+      return;
+    }
+
+    masm.branch32(Assembler::BelowOrEqual, initLength, Imm32(index),
+                  &falseBranch);
+
+    NativeObject::elementsSizeMustNotOverflow();
+    Address address = Address(elements, index * sizeof(Value));
+    masm.branchTestMagic(Assembler::Equal, address, &falseBranch);
+  } else {
+    Register index = ToRegister(lir->index());
+
+    Label negativeIntCheck;
+    Label* failedInitLength = &falseBranch;
+    if (mir->needsNegativeIntCheck()) {
+      failedInitLength = &negativeIntCheck;
+    }
+
+    masm.branch32(Assembler::BelowOrEqual, initLength, index, failedInitLength);
+
+    BaseObjectElementIndex address(elements, index);
+    masm.branchTestMagic(Assembler::Equal, address, &falseBranch);
+
+    if (mir->needsNegativeIntCheck()) {
+      masm.jump(&trueBranch);
+      masm.bind(&negativeIntCheck);
+
+      bailoutCmp32(Assembler::LessThan, index, Imm32(0), lir->snapshot());
+
+      masm.jump(&falseBranch);
+    }
+  }
+
+  masm.bind(&trueBranch);
+  masm.move32(Imm32(1), output);
+  masm.jump(&done);
+
+  masm.bind(&falseBranch);
+  masm.move32(Imm32(0), output);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitGuardElementNotHole(LGuardElementNotHole* lir) {
+  Register elements = ToRegister(lir->elements());
+  const LAllocation* index = lir->index();
+
+  Label testMagic;
+  if (index->isConstant()) {
+    Address address(elements, ToInt32(index) * sizeof(js::Value));
+    masm.branchTestMagic(Assembler::Equal, address, &testMagic);
+  } else {
+    BaseObjectElementIndex address(elements, ToRegister(index));
+    masm.branchTestMagic(Assembler::Equal, address, &testMagic);
+  }
+  bailoutFrom(&testMagic, lir->snapshot());
+}
+
+void CodeGenerator::visitInstanceOfO(LInstanceOfO* ins) {
+  emitInstanceOf(ins, ins->rhs());
+}
+
+void CodeGenerator::visitInstanceOfV(LInstanceOfV* ins) {
+  emitInstanceOf(ins, ins->rhs());
+}
+
+void CodeGenerator::emitInstanceOf(LInstruction* ins,
+                                   const LAllocation* prototypeObject) {
+  // This path implements fun_hasInstance when the function's prototype is
+  // known to be prototypeObject.
+
+  Label done;
+  Register output = ToRegister(ins->getDef(0));
+
+  // If the lhs is a primitive, the result is false.
+  Register objReg;
+  if (ins->isInstanceOfV()) {
+    Label isObject;
+    ValueOperand lhsValue = ToValue(ins, LInstanceOfV::LHS);
+    masm.branchTestObject(Assembler::Equal, lhsValue, &isObject);
+    masm.mov(ImmWord(0), output);
+    masm.jump(&done);
+    masm.bind(&isObject);
+    objReg = masm.extractObject(lhsValue, output);
+  } else {
+    objReg = ToRegister(ins->toInstanceOfO()->lhs());
+  }
+
+  mozilla::Maybe<ImmGCPtr> protoPtr;
+  mozilla::Maybe<Register> protoReg;
+  if (prototypeObject->isConstant()) {
+    protoPtr.emplace(&prototypeObject->toConstant()->toObject());
+  } else {
+    protoReg.emplace(ToRegister(prototypeObject));
+  }
+
+  // Crawl the lhs's prototype chain in a loop to search for prototypeObject.
+  // This follows the main loop of js::IsPrototypeOf, though additionally breaks
+  // out of the loop on Proxy::LazyProto.
+
+  // Load the lhs's prototype.
+  masm.loadObjProto(objReg, output);
+
+  Label testLazy;
+  {
+    Label loopPrototypeChain;
+    masm.bind(&loopPrototypeChain);
+
+    // Test for the target prototype object.
+    Label notPrototypeObject;
+    if (protoPtr) {
+      masm.branchPtr(Assembler::NotEqual, output, *protoPtr,
+                     &notPrototypeObject);
+    } else {
+      masm.branchPtr(Assembler::NotEqual, output, *protoReg,
+                     &notPrototypeObject);
+    }
+    masm.mov(ImmWord(1), output);
+    masm.jump(&done);
+    masm.bind(&notPrototypeObject);
+
+    MOZ_ASSERT(uintptr_t(TaggedProto::LazyProto) == 1);
+
+    // Test for nullptr or Proxy::LazyProto
+    masm.branchPtr(Assembler::BelowOrEqual, output, ImmWord(1), &testLazy);
+
+    // Load the current object's prototype.
+    masm.loadObjProto(output, output);
+
+    masm.jump(&loopPrototypeChain);
+  }
+
+  // Make a VM call if an object with a lazy proto was found on the prototype
+  // chain. This currently occurs only for cross compartment wrappers, which
+  // we do not expect to be compared with non-wrapper functions from this
+  // compartment. Otherwise, we stopped on a nullptr prototype and the output
+  // register is already correct.
+
+  using Fn = bool (*)(JSContext*, HandleObject, JSObject*, bool*);
+  OutOfLineCode* ool;
+  if (protoPtr) {
+    ool = oolCallVM<Fn, IsPrototypeOf>(ins, ArgList(*protoPtr, objReg),
+                                       StoreRegisterTo(output));
+  } else {
+    ool = oolCallVM<Fn, IsPrototypeOf>(ins, ArgList(*protoReg, objReg),
+                                       StoreRegisterTo(output));
+  }
+
+  // Regenerate the original lhs object for the VM call.
+  Label regenerate, *lazyEntry;
+  if (objReg != output) {
+    lazyEntry = ool->entry();
+  } else {
+    masm.bind(&regenerate);
+    lazyEntry = &regenerate;
+    if (ins->isInstanceOfV()) {
+      ValueOperand lhsValue = ToValue(ins, LInstanceOfV::LHS);
+      objReg = masm.extractObject(lhsValue, output);
+    } else {
+      objReg = ToRegister(ins->toInstanceOfO()->lhs());
+    }
+    MOZ_ASSERT(objReg == output);
+    masm.jump(ool->entry());
+  }
+
+  masm.bind(&testLazy);
+  masm.branchPtr(Assembler::Equal, output, ImmWord(1), lazyEntry);
+
+  masm.bind(&done);
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitInstanceOfCache(LInstanceOfCache* ins) {
+  // The Lowering ensures that RHS is an object, and that LHS is a value.
+  LiveRegisterSet liveRegs = ins->safepoint()->liveRegs();
+  TypedOrValueRegister lhs =
+      TypedOrValueRegister(ToValue(ins, LInstanceOfCache::LHS));
+  Register rhs = ToRegister(ins->rhs());
+  Register output = ToRegister(ins->output());
+
+  IonInstanceOfIC ic(liveRegs, lhs, rhs, output);
+  addIC(ins, allocateIC(ic));
+}
+
+void CodeGenerator::visitGetDOMProperty(LGetDOMProperty* ins) {
+  const Register JSContextReg = ToRegister(ins->getJSContextReg());
+  const Register ObjectReg = ToRegister(ins->getObjectReg());
+  const Register PrivateReg = ToRegister(ins->getPrivReg());
+  const Register ValueReg = ToRegister(ins->getValueReg());
+
+  Label haveValue;
+  if (ins->mir()->valueMayBeInSlot()) {
+    size_t slot = ins->mir()->domMemberSlotIndex();
+    // It's a bit annoying to redo these slot calculations, which duplcate
+    // LSlots and a few other things like that, but I'm not sure there's a
+    // way to reuse those here.
+    //
+    // If this ever gets fixed to work with proxies (by not assuming that
+    // reserved slot indices, which is what domMemberSlotIndex() returns,
+    // match fixed slot indices), we can reenable MGetDOMProperty for
+    // proxies in IonBuilder.
+    if (slot < NativeObject::MAX_FIXED_SLOTS) {
+      masm.loadValue(Address(ObjectReg, NativeObject::getFixedSlotOffset(slot)),
+                     JSReturnOperand);
+    } else {
+      // It's a dynamic slot.
+      slot -= NativeObject::MAX_FIXED_SLOTS;
+      // Use PrivateReg as a scratch register for the slots pointer.
+      masm.loadPtr(Address(ObjectReg, NativeObject::offsetOfSlots()),
+                   PrivateReg);
+      masm.loadValue(Address(PrivateReg, slot * sizeof(js::Value)),
+                     JSReturnOperand);
+    }
+    masm.branchTestUndefined(Assembler::NotEqual, JSReturnOperand, &haveValue);
+  }
+
+  DebugOnly<uint32_t> initialStack = masm.framePushed();
+
+  masm.checkStackAlignment();
+
+  // Make space for the outparam.  Pre-initialize it to UndefinedValue so we
+  // can trace it at GC time.
+  masm.Push(UndefinedValue());
+  // We pass the pointer to our out param as an instance of
+  // JSJitGetterCallArgs, since on the binary level it's the same thing.
+  static_assert(sizeof(JSJitGetterCallArgs) == sizeof(Value*));
+  masm.moveStackPtrTo(ValueReg);
+
+  masm.Push(ObjectReg);
+
+  LoadDOMPrivate(masm, ObjectReg, PrivateReg, ins->mir()->objectKind());
+
+  // Rooting will happen at GC time.
+  masm.moveStackPtrTo(ObjectReg);
+
+  Realm* getterRealm = ins->mir()->getterRealm();
+  if (gen->realm->realmPtr() != getterRealm) {
+    // We use JSContextReg as scratch register here.
+    masm.switchToRealm(getterRealm, JSContextReg);
+  }
+
+  uint32_t safepointOffset = masm.buildFakeExitFrame(JSContextReg);
+  masm.loadJSContext(JSContextReg);
+  masm.enterFakeExitFrame(JSContextReg, JSContextReg,
+                          ExitFrameType::IonDOMGetter);
+
+  markSafepointAt(safepointOffset, ins);
+
+  masm.setupUnalignedABICall(JSContextReg);
+  masm.loadJSContext(JSContextReg);
+  masm.passABIArg(JSContextReg);
+  masm.passABIArg(ObjectReg);
+  masm.passABIArg(PrivateReg);
+  masm.passABIArg(ValueReg);
+  masm.callWithABI(DynamicFunction<JSJitGetterOp>(ins->mir()->fun()),
+                   MoveOp::GENERAL,
+                   CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+  if (ins->mir()->isInfallible()) {
+    masm.loadValue(Address(masm.getStackPointer(),
+                           IonDOMExitFrameLayout::offsetOfResult()),
+                   JSReturnOperand);
+  } else {
+    masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+    masm.loadValue(Address(masm.getStackPointer(),
+                           IonDOMExitFrameLayout::offsetOfResult()),
+                   JSReturnOperand);
+  }
+
+  // Switch back to the current realm if needed. Note: if the getter threw an
+  // exception, the exception handler will do this.
+  if (gen->realm->realmPtr() != getterRealm) {
+    static_assert(!JSReturnOperand.aliases(ReturnReg),
+                  "Clobbering ReturnReg should not affect the return value");
+    masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+  }
+
+  // Until C++ code is instrumented against Spectre, prevent speculative
+  // execution from returning any private data.
+  if (JitOptions.spectreJitToCxxCalls && ins->mir()->hasLiveDefUses()) {
+    masm.speculationBarrier();
+  }
+
+  masm.adjustStack(IonDOMExitFrameLayout::Size());
+
+  masm.bind(&haveValue);
+
+  MOZ_ASSERT(masm.framePushed() == initialStack);
+}
+
+void CodeGenerator::visitGetDOMMemberV(LGetDOMMemberV* ins) {
+  // It's simpler to duplicate visitLoadFixedSlotV here than it is to try to
+  // use an LLoadFixedSlotV or some subclass of it for this case: that would
+  // require us to have MGetDOMMember inherit from MLoadFixedSlot, and then
+  // we'd have to duplicate a bunch of stuff we now get for free from
+  // MGetDOMProperty.
+  //
+  // If this ever gets fixed to work with proxies (by not assuming that
+  // reserved slot indices, which is what domMemberSlotIndex() returns,
+  // match fixed slot indices), we can reenable MGetDOMMember for
+  // proxies in IonBuilder.
+  Register object = ToRegister(ins->object());
+  size_t slot = ins->mir()->domMemberSlotIndex();
+  ValueOperand result = ToOutValue(ins);
+
+  masm.loadValue(Address(object, NativeObject::getFixedSlotOffset(slot)),
+                 result);
+}
+
+void CodeGenerator::visitGetDOMMemberT(LGetDOMMemberT* ins) {
+  // It's simpler to duplicate visitLoadFixedSlotT here than it is to try to
+  // use an LLoadFixedSlotT or some subclass of it for this case: that would
+  // require us to have MGetDOMMember inherit from MLoadFixedSlot, and then
+  // we'd have to duplicate a bunch of stuff we now get for free from
+  // MGetDOMProperty.
+  //
+  // If this ever gets fixed to work with proxies (by not assuming that
+  // reserved slot indices, which is what domMemberSlotIndex() returns,
+  // match fixed slot indices), we can reenable MGetDOMMember for
+  // proxies in IonBuilder.
+  Register object = ToRegister(ins->object());
+  size_t slot = ins->mir()->domMemberSlotIndex();
+  AnyRegister result = ToAnyRegister(ins->getDef(0));
+  MIRType type = ins->mir()->type();
+
+  masm.loadUnboxedValue(Address(object, NativeObject::getFixedSlotOffset(slot)),
+                        type, result);
+}
+
+void CodeGenerator::visitSetDOMProperty(LSetDOMProperty* ins) {
+  const Register JSContextReg = ToRegister(ins->getJSContextReg());
+  const Register ObjectReg = ToRegister(ins->getObjectReg());
+  const Register PrivateReg = ToRegister(ins->getPrivReg());
+  const Register ValueReg = ToRegister(ins->getValueReg());
+
+  DebugOnly<uint32_t> initialStack = masm.framePushed();
+
+  masm.checkStackAlignment();
+
+  // Push the argument. Rooting will happen at GC time.
+  ValueOperand argVal = ToValue(ins, LSetDOMProperty::Value);
+  masm.Push(argVal);
+  // We pass the pointer to our out param as an instance of
+  // JSJitGetterCallArgs, since on the binary level it's the same thing.
+  static_assert(sizeof(JSJitSetterCallArgs) == sizeof(Value*));
+  masm.moveStackPtrTo(ValueReg);
+
+  masm.Push(ObjectReg);
+
+  LoadDOMPrivate(masm, ObjectReg, PrivateReg, ins->mir()->objectKind());
+
+  // Rooting will happen at GC time.
+  masm.moveStackPtrTo(ObjectReg);
+
+  Realm* setterRealm = ins->mir()->setterRealm();
+  if (gen->realm->realmPtr() != setterRealm) {
+    // We use JSContextReg as scratch register here.
+    masm.switchToRealm(setterRealm, JSContextReg);
+  }
+
+  uint32_t safepointOffset = masm.buildFakeExitFrame(JSContextReg);
+  masm.loadJSContext(JSContextReg);
+  masm.enterFakeExitFrame(JSContextReg, JSContextReg,
+                          ExitFrameType::IonDOMSetter);
+
+  markSafepointAt(safepointOffset, ins);
+
+  masm.setupUnalignedABICall(JSContextReg);
+  masm.loadJSContext(JSContextReg);
+  masm.passABIArg(JSContextReg);
+  masm.passABIArg(ObjectReg);
+  masm.passABIArg(PrivateReg);
+  masm.passABIArg(ValueReg);
+  masm.callWithABI(DynamicFunction<JSJitSetterOp>(ins->mir()->fun()),
+                   MoveOp::GENERAL,
+                   CheckUnsafeCallWithABI::DontCheckHasExitFrame);
+
+  masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+  // Switch back to the current realm if needed. Note: if the setter threw an
+  // exception, the exception handler will do this.
+  if (gen->realm->realmPtr() != setterRealm) {
+    masm.switchToRealm(gen->realm->realmPtr(), ReturnReg);
+  }
+
+  masm.adjustStack(IonDOMExitFrameLayout::Size());
+
+  MOZ_ASSERT(masm.framePushed() == initialStack);
+}
+
+void CodeGenerator::visitLoadDOMExpandoValue(LLoadDOMExpandoValue* ins) {
+  Register proxy = ToRegister(ins->proxy());
+  ValueOperand out = ToOutValue(ins);
+
+  masm.loadPtr(Address(proxy, ProxyObject::offsetOfReservedSlots()),
+               out.scratchReg());
+  masm.loadValue(Address(out.scratchReg(),
+                         js::detail::ProxyReservedSlots::offsetOfPrivateSlot()),
+                 out);
+}
+
+void CodeGenerator::visitLoadDOMExpandoValueGuardGeneration(
+    LLoadDOMExpandoValueGuardGeneration* ins) {
+  Register proxy = ToRegister(ins->proxy());
+  ValueOperand out = ToOutValue(ins);
+
+  Label bail;
+  masm.loadDOMExpandoValueGuardGeneration(proxy, out,
+                                          ins->mir()->expandoAndGeneration(),
+                                          ins->mir()->generation(), &bail);
+  bailoutFrom(&bail, ins->snapshot());
+}
+
+void CodeGenerator::visitLoadDOMExpandoValueIgnoreGeneration(
+    LLoadDOMExpandoValueIgnoreGeneration* ins) {
+  Register proxy = ToRegister(ins->proxy());
+  ValueOperand out = ToOutValue(ins);
+
+  masm.loadPtr(Address(proxy, ProxyObject::offsetOfReservedSlots()),
+               out.scratchReg());
+
+  // Load the ExpandoAndGeneration* from the PrivateValue.
+  masm.loadPrivate(
+      Address(out.scratchReg(),
+              js::detail::ProxyReservedSlots::offsetOfPrivateSlot()),
+      out.scratchReg());
+
+  // Load expandoAndGeneration->expando into the output Value register.
+  masm.loadValue(
+      Address(out.scratchReg(), ExpandoAndGeneration::offsetOfExpando()), out);
+}
+
+void CodeGenerator::visitGuardDOMExpandoMissingOrGuardShape(
+    LGuardDOMExpandoMissingOrGuardShape* ins) {
+  Register temp = ToRegister(ins->temp());
+  ValueOperand input = ToValue(ins, LGuardDOMExpandoMissingOrGuardShape::Input);
+
+  Label done;
+  masm.branchTestUndefined(Assembler::Equal, input, &done);
+
+  masm.debugAssertIsObject(input);
+  masm.unboxObject(input, temp);
+  // The expando object is not used in this case, so we don't need Spectre
+  // mitigations.
+  Label bail;
+  masm.branchTestObjShapeNoSpectreMitigations(Assembler::NotEqual, temp,
+                                              ins->mir()->shape(), &bail);
+  bailoutFrom(&bail, ins->snapshot());
+
+  masm.bind(&done);
+}
+
+class OutOfLineIsCallable : public OutOfLineCodeBase<CodeGenerator> {
+  Register object_;
+  Register output_;
+
+ public:
+  OutOfLineIsCallable(Register object, Register output)
+      : object_(object), output_(output) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineIsCallable(this);
+  }
+  Register object() const { return object_; }
+  Register output() const { return output_; }
+};
+
+void CodeGenerator::visitIsCallableO(LIsCallableO* ins) {
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+
+  OutOfLineIsCallable* ool = new (alloc()) OutOfLineIsCallable(object, output);
+  addOutOfLineCode(ool, ins->mir());
+
+  masm.isCallable(object, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitIsCallableV(LIsCallableV* ins) {
+  ValueOperand val = ToValue(ins, LIsCallableV::Value);
+  Register output = ToRegister(ins->output());
+  Register temp = ToRegister(ins->temp());
+
+  Label notObject;
+  masm.fallibleUnboxObject(val, temp, &notObject);
+
+  OutOfLineIsCallable* ool = new (alloc()) OutOfLineIsCallable(temp, output);
+  addOutOfLineCode(ool, ins->mir());
+
+  masm.isCallable(temp, output, ool->entry());
+  masm.jump(ool->rejoin());
+
+  masm.bind(&notObject);
+  masm.move32(Imm32(0), output);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineIsCallable(OutOfLineIsCallable* ool) {
+  Register object = ool->object();
+  Register output = ool->output();
+
+  saveVolatile(output);
+  using Fn = bool (*)(JSObject * obj);
+  masm.setupUnalignedABICall(output);
+  masm.passABIArg(object);
+  masm.callWithABI<Fn, ObjectIsCallable>();
+  masm.storeCallBoolResult(output);
+  restoreVolatile(output);
+  masm.jump(ool->rejoin());
+}
+
+class OutOfLineIsConstructor : public OutOfLineCodeBase<CodeGenerator> {
+  LIsConstructor* ins_;
+
+ public:
+  explicit OutOfLineIsConstructor(LIsConstructor* ins) : ins_(ins) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineIsConstructor(this);
+  }
+  LIsConstructor* ins() const { return ins_; }
+};
+
+void CodeGenerator::visitIsConstructor(LIsConstructor* ins) {
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+
+  OutOfLineIsConstructor* ool = new (alloc()) OutOfLineIsConstructor(ins);
+  addOutOfLineCode(ool, ins->mir());
+
+  masm.isConstructor(object, output, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitOutOfLineIsConstructor(OutOfLineIsConstructor* ool) {
+  LIsConstructor* ins = ool->ins();
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+
+  saveVolatile(output);
+  using Fn = bool (*)(JSObject * obj);
+  masm.setupUnalignedABICall(output);
+  masm.passABIArg(object);
+  masm.callWithABI<Fn, ObjectIsConstructor>();
+  masm.storeCallBoolResult(output);
+  restoreVolatile(output);
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitIsCrossRealmArrayConstructor(
+    LIsCrossRealmArrayConstructor* ins) {
+  Register object = ToRegister(ins->object());
+  Register output = ToRegister(ins->output());
+
+  masm.setIsCrossRealmArrayConstructor(object, output);
+}
+
+static void EmitObjectIsArray(MacroAssembler& masm, OutOfLineCode* ool,
+                              Register obj, Register output,
+                              Label* notArray = nullptr) {
+  masm.loadObjClassUnsafe(obj, output);
+
+  Label isArray;
+  masm.branchPtr(Assembler::Equal, output, ImmPtr(&ArrayObject::class_),
+                 &isArray);
+
+  // Branch to OOL path if it's a proxy.
+  masm.branchTestClassIsProxy(true, output, ool->entry());
+
+  if (notArray) {
+    masm.bind(notArray);
+  }
+  masm.move32(Imm32(0), output);
+  masm.jump(ool->rejoin());
+
+  masm.bind(&isArray);
+  masm.move32(Imm32(1), output);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitIsArrayO(LIsArrayO* lir) {
+  Register object = ToRegister(lir->object());
+  Register output = ToRegister(lir->output());
+
+  using Fn = bool (*)(JSContext*, HandleObject, bool*);
+  OutOfLineCode* ool = oolCallVM<Fn, js::IsArrayFromJit>(
+      lir, ArgList(object), StoreRegisterTo(output));
+  EmitObjectIsArray(masm, ool, object, output);
+}
+
+void CodeGenerator::visitIsArrayV(LIsArrayV* lir) {
+  ValueOperand val = ToValue(lir, LIsArrayV::Value);
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+
+  Label notArray;
+  masm.fallibleUnboxObject(val, temp, &notArray);
+
+  using Fn = bool (*)(JSContext*, HandleObject, bool*);
+  OutOfLineCode* ool = oolCallVM<Fn, js::IsArrayFromJit>(
+      lir, ArgList(temp), StoreRegisterTo(output));
+  EmitObjectIsArray(masm, ool, temp, output, &notArray);
+}
+
+void CodeGenerator::visitIsTypedArray(LIsTypedArray* lir) {
+  Register object = ToRegister(lir->object());
+  Register output = ToRegister(lir->output());
+
+  OutOfLineCode* ool = nullptr;
+  if (lir->mir()->isPossiblyWrapped()) {
+    using Fn = bool (*)(JSContext*, JSObject*, bool*);
+    ool = oolCallVM<Fn, jit::IsPossiblyWrappedTypedArray>(
+        lir, ArgList(object), StoreRegisterTo(output));
+  }
+
+  Label notTypedArray;
+  Label done;
+
+  masm.loadObjClassUnsafe(object, output);
+  masm.branchIfClassIsNotTypedArray(output, &notTypedArray);
+
+  masm.move32(Imm32(1), output);
+  masm.jump(&done);
+  masm.bind(&notTypedArray);
+  if (ool) {
+    masm.branchTestClassIsProxy(true, output, ool->entry());
+  }
+  masm.move32(Imm32(0), output);
+  masm.bind(&done);
+  if (ool) {
+    masm.bind(ool->rejoin());
+  }
+}
+
+void CodeGenerator::visitIsObject(LIsObject* ins) {
+  Register output = ToRegister(ins->output());
+  ValueOperand value = ToValue(ins, LIsObject::Input);
+  masm.testObjectSet(Assembler::Equal, value, output);
+}
+
+void CodeGenerator::visitIsObjectAndBranch(LIsObjectAndBranch* ins) {
+  ValueOperand value = ToValue(ins, LIsObjectAndBranch::Input);
+  testObjectEmitBranch(Assembler::Equal, value, ins->ifTrue(), ins->ifFalse());
+}
+
+void CodeGenerator::visitIsNullOrUndefined(LIsNullOrUndefined* ins) {
+  Register output = ToRegister(ins->output());
+  ValueOperand value = ToValue(ins, LIsNullOrUndefined::Input);
+
+  Label isNotNull, done;
+  masm.branchTestNull(Assembler::NotEqual, value, &isNotNull);
+
+  masm.move32(Imm32(1), output);
+  masm.jump(&done);
+
+  masm.bind(&isNotNull);
+  masm.testUndefinedSet(Assembler::Equal, value, output);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitIsNullOrUndefinedAndBranch(
+    LIsNullOrUndefinedAndBranch* ins) {
+  Label* ifTrue = getJumpLabelForBranch(ins->ifTrue());
+  Label* ifFalse = getJumpLabelForBranch(ins->ifFalse());
+  ValueOperand value = ToValue(ins, LIsNullOrUndefinedAndBranch::Input);
+
+  ScratchTagScope tag(masm, value);
+  masm.splitTagForTest(value, tag);
+
+  masm.branchTestNull(Assembler::Equal, tag, ifTrue);
+  masm.branchTestUndefined(Assembler::Equal, tag, ifTrue);
+
+  if (!isNextBlock(ins->ifFalse()->lir())) {
+    masm.jump(ifFalse);
+  }
+}
+
+void CodeGenerator::loadOutermostJSScript(Register reg) {
+  // The "outermost" JSScript means the script that we are compiling
+  // basically; this is not always the script associated with the
+  // current basic block, which might be an inlined script.
+
+  MIRGraph& graph = current->mir()->graph();
+  MBasicBlock* entryBlock = graph.entryBlock();
+  masm.movePtr(ImmGCPtr(entryBlock->info().script()), reg);
+}
+
+void CodeGenerator::loadJSScriptForBlock(MBasicBlock* block, Register reg) {
+  // The current JSScript means the script for the current
+  // basic block. This may be an inlined script.
+
+  JSScript* script = block->info().script();
+  masm.movePtr(ImmGCPtr(script), reg);
+}
+
+void CodeGenerator::visitHasClass(LHasClass* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register output = ToRegister(ins->output());
+
+  masm.loadObjClassUnsafe(lhs, output);
+  masm.cmpPtrSet(Assembler::Equal, output, ImmPtr(ins->mir()->getClass()),
+                 output);
+}
+
+void CodeGenerator::visitGuardToClass(LGuardToClass* ins) {
+  Register lhs = ToRegister(ins->lhs());
+  Register temp = ToRegister(ins->temp());
+
+  // branchTestObjClass may zero the object register on speculative paths
+  // (we should have a defineReuseInput allocation in this case).
+  Register spectreRegToZero = lhs;
+
+  Label notEqual;
+
+  masm.branchTestObjClass(Assembler::NotEqual, lhs, ins->mir()->getClass(),
+                          temp, spectreRegToZero, &notEqual);
+
+  // Can't return null-return here, so bail.
+  bailoutFrom(&notEqual, ins->snapshot());
+}
+
+void CodeGenerator::visitObjectClassToString(LObjectClassToString* lir) {
+  Register obj = ToRegister(lir->object());
+  Register temp = ToRegister(lir->temp());
+
+  using Fn = JSString* (*)(JSContext*, JSObject*);
+  masm.setupUnalignedABICall(temp);
+  masm.loadJSContext(temp);
+  masm.passABIArg(temp);
+  masm.passABIArg(obj);
+  masm.callWithABI<Fn, js::ObjectClassToString>();
+
+  bailoutCmpPtr(Assembler::Equal, ReturnReg, ImmWord(0), lir->snapshot());
+}
+
+void CodeGenerator::visitWasmParameter(LWasmParameter* lir) {}
+
+void CodeGenerator::visitWasmParameterI64(LWasmParameterI64* lir) {}
+
+void CodeGenerator::visitWasmReturn(LWasmReturn* lir) {
+  // Don't emit a jump to the return label if this is the last block.
+  if (current->mir() != *gen->graph().poBegin()) {
+    masm.jump(&returnLabel_);
+  }
+}
+
+void CodeGenerator::visitWasmReturnI64(LWasmReturnI64* lir) {
+  // Don't emit a jump to the return label if this is the last block.
+  if (current->mir() != *gen->graph().poBegin()) {
+    masm.jump(&returnLabel_);
+  }
+}
+
+void CodeGenerator::visitWasmReturnVoid(LWasmReturnVoid* lir) {
+  // Don't emit a jump to the return label if this is the last block.
+  if (current->mir() != *gen->graph().poBegin()) {
+    masm.jump(&returnLabel_);
+  }
+}
+
+void CodeGenerator::emitAssertRangeI(const Range* r, Register input) {
+  // Check the lower bound.
+  if (r->hasInt32LowerBound() && r->lower() > INT32_MIN) {
+    Label success;
+    masm.branch32(Assembler::GreaterThanOrEqual, input, Imm32(r->lower()),
+                  &success);
+    masm.assumeUnreachable(
+        "Integer input should be equal or higher than Lowerbound.");
+    masm.bind(&success);
+  }
+
+  // Check the upper bound.
+  if (r->hasInt32UpperBound() && r->upper() < INT32_MAX) {
+    Label success;
+    masm.branch32(Assembler::LessThanOrEqual, input, Imm32(r->upper()),
+                  &success);
+    masm.assumeUnreachable(
+        "Integer input should be lower or equal than Upperbound.");
+    masm.bind(&success);
+  }
+
+  // For r->canHaveFractionalPart(), r->canBeNegativeZero(), and
+  // r->exponent(), there's nothing to check, because if we ended up in the
+  // integer range checking code, the value is already in an integer register
+  // in the integer range.
+}
+
+void CodeGenerator::emitAssertRangeD(const Range* r, FloatRegister input,
+                                     FloatRegister temp) {
+  // Check the lower bound.
+  if (r->hasInt32LowerBound()) {
+    Label success;
+    masm.loadConstantDouble(r->lower(), temp);
+    if (r->canBeNaN()) {
+      masm.branchDouble(Assembler::DoubleUnordered, input, input, &success);
+    }
+    masm.branchDouble(Assembler::DoubleGreaterThanOrEqual, input, temp,
+                      &success);
+    masm.assumeUnreachable(
+        "Double input should be equal or higher than Lowerbound.");
+    masm.bind(&success);
+  }
+  // Check the upper bound.
+  if (r->hasInt32UpperBound()) {
+    Label success;
+    masm.loadConstantDouble(r->upper(), temp);
+    if (r->canBeNaN()) {
+      masm.branchDouble(Assembler::DoubleUnordered, input, input, &success);
+    }
+    masm.branchDouble(Assembler::DoubleLessThanOrEqual, input, temp, &success);
+    masm.assumeUnreachable(
+        "Double input should be lower or equal than Upperbound.");
+    masm.bind(&success);
+  }
+
+  // This code does not yet check r->canHaveFractionalPart(). This would require
+  // new assembler interfaces to make rounding instructions available.
+
+  if (!r->canBeNegativeZero()) {
+    Label success;
+
+    // First, test for being equal to 0.0, which also includes -0.0.
+    masm.loadConstantDouble(0.0, temp);
+    masm.branchDouble(Assembler::DoubleNotEqualOrUnordered, input, temp,
+                      &success);
+
+    // The easiest way to distinguish -0.0 from 0.0 is that 1.0/-0.0 is
+    // -Infinity instead of Infinity.
+    masm.loadConstantDouble(1.0, temp);
+    masm.divDouble(input, temp);
+    masm.branchDouble(Assembler::DoubleGreaterThan, temp, input, &success);
+
+    masm.assumeUnreachable("Input shouldn't be negative zero.");
+
+    masm.bind(&success);
+  }
+
+  if (!r->hasInt32Bounds() && !r->canBeInfiniteOrNaN() &&
+      r->exponent() < FloatingPoint<double>::kExponentBias) {
+    // Check the bounds implied by the maximum exponent.
+    Label exponentLoOk;
+    masm.loadConstantDouble(pow(2.0, r->exponent() + 1), temp);
+    masm.branchDouble(Assembler::DoubleUnordered, input, input, &exponentLoOk);
+    masm.branchDouble(Assembler::DoubleLessThanOrEqual, input, temp,
+                      &exponentLoOk);
+    masm.assumeUnreachable("Check for exponent failed.");
+    masm.bind(&exponentLoOk);
+
+    Label exponentHiOk;
+    masm.loadConstantDouble(-pow(2.0, r->exponent() + 1), temp);
+    masm.branchDouble(Assembler::DoubleUnordered, input, input, &exponentHiOk);
+    masm.branchDouble(Assembler::DoubleGreaterThanOrEqual, input, temp,
+                      &exponentHiOk);
+    masm.assumeUnreachable("Check for exponent failed.");
+    masm.bind(&exponentHiOk);
+  } else if (!r->hasInt32Bounds() && !r->canBeNaN()) {
+    // If we think the value can't be NaN, check that it isn't.
+    Label notnan;
+    masm.branchDouble(Assembler::DoubleOrdered, input, input, &notnan);
+    masm.assumeUnreachable("Input shouldn't be NaN.");
+    masm.bind(&notnan);
+
+    // If we think the value also can't be an infinity, check that it isn't.
+    if (!r->canBeInfiniteOrNaN()) {
+      Label notposinf;
+      masm.loadConstantDouble(PositiveInfinity<double>(), temp);
+      masm.branchDouble(Assembler::DoubleLessThan, input, temp, &notposinf);
+      masm.assumeUnreachable("Input shouldn't be +Inf.");
+      masm.bind(&notposinf);
+
+      Label notneginf;
+      masm.loadConstantDouble(NegativeInfinity<double>(), temp);
+      masm.branchDouble(Assembler::DoubleGreaterThan, input, temp, &notneginf);
+      masm.assumeUnreachable("Input shouldn't be -Inf.");
+      masm.bind(&notneginf);
+    }
+  }
+}
+
+void CodeGenerator::visitAssertClass(LAssertClass* ins) {
+  Register obj = ToRegister(ins->input());
+  Register temp = ToRegister(ins->getTemp(0));
+
+  Label success;
+  masm.branchTestObjClassNoSpectreMitigations(
+      Assembler::Equal, obj, ins->mir()->getClass(), temp, &success);
+  masm.assumeUnreachable("Wrong KnownClass during run-time");
+  masm.bind(&success);
+}
+
+void CodeGenerator::visitAssertShape(LAssertShape* ins) {
+  Register obj = ToRegister(ins->input());
+
+  Label success;
+  masm.branchTestObjShapeNoSpectreMitigations(Assembler::Equal, obj,
+                                              ins->mir()->shape(), &success);
+  masm.assumeUnreachable("Wrong Shape during run-time");
+  masm.bind(&success);
+}
+
+void CodeGenerator::visitAssertResultV(LAssertResultV* ins) {
+#ifdef DEBUG
+  const ValueOperand value = ToValue(ins, LAssertResultV::Input);
+  emitAssertResultV(value, ins->mirRaw());
+#else
+  MOZ_CRASH("LAssertResultV is debug only");
+#endif
+}
+
+void CodeGenerator::visitAssertResultT(LAssertResultT* ins) {
+#ifdef DEBUG
+  Register input = ToRegister(ins->input());
+  emitAssertGCThingResult(input, ins->mirRaw());
+#else
+  MOZ_CRASH("LAssertResultT is debug only");
+#endif
+}
+
+void CodeGenerator::visitAssertRangeI(LAssertRangeI* ins) {
+  Register input = ToRegister(ins->input());
+  const Range* r = ins->range();
+
+  emitAssertRangeI(r, input);
+}
+
+void CodeGenerator::visitAssertRangeD(LAssertRangeD* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  FloatRegister temp = ToFloatRegister(ins->temp());
+  const Range* r = ins->range();
+
+  emitAssertRangeD(r, input, temp);
+}
+
+void CodeGenerator::visitAssertRangeF(LAssertRangeF* ins) {
+  FloatRegister input = ToFloatRegister(ins->input());
+  FloatRegister temp = ToFloatRegister(ins->temp());
+  FloatRegister temp2 = ToFloatRegister(ins->temp2());
+
+  const Range* r = ins->range();
+
+  masm.convertFloat32ToDouble(input, temp);
+  emitAssertRangeD(r, temp, temp2);
+}
+
+void CodeGenerator::visitAssertRangeV(LAssertRangeV* ins) {
+  const Range* r = ins->range();
+  const ValueOperand value = ToValue(ins, LAssertRangeV::Input);
+  Label done;
+
+  {
+    ScratchTagScope tag(masm, value);
+    masm.splitTagForTest(value, tag);
+
+    {
+      Label isNotInt32;
+      masm.branchTestInt32(Assembler::NotEqual, tag, &isNotInt32);
+      {
+        ScratchTagScopeRelease _(&tag);
+        Register unboxInt32 = ToTempUnboxRegister(ins->temp());
+        Register input = masm.extractInt32(value, unboxInt32);
+        emitAssertRangeI(r, input);
+        masm.jump(&done);
+      }
+      masm.bind(&isNotInt32);
+    }
+
+    {
+      Label isNotDouble;
+      masm.branchTestDouble(Assembler::NotEqual, tag, &isNotDouble);
+      {
+        ScratchTagScopeRelease _(&tag);
+        FloatRegister input = ToFloatRegister(ins->floatTemp1());
+        FloatRegister temp = ToFloatRegister(ins->floatTemp2());
+        masm.unboxDouble(value, input);
+        emitAssertRangeD(r, input, temp);
+        masm.jump(&done);
+      }
+      masm.bind(&isNotDouble);
+    }
+  }
+
+  masm.assumeUnreachable("Incorrect range for Value.");
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitInterruptCheck(LInterruptCheck* lir) {
+  using Fn = bool (*)(JSContext*);
+  OutOfLineCode* ool =
+      oolCallVM<Fn, InterruptCheck>(lir, ArgList(), StoreNothing());
+
+  const void* interruptAddr = gen->runtime->addressOfInterruptBits();
+  masm.branch32(Assembler::NotEqual, AbsoluteAddress(interruptAddr), Imm32(0),
+                ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitWasmInterruptCheck(LWasmInterruptCheck* lir) {
+  MOZ_ASSERT(gen->compilingWasm());
+
+  masm.wasmInterruptCheck(ToRegister(lir->tlsPtr()),
+                          lir->mir()->bytecodeOffset());
+
+  markSafepointAt(masm.currentOffset(), lir);
+
+  // Note that masm.framePushed() doesn't include the register dump area.
+  // That will be taken into account when the StackMap is created from the
+  // LSafepoint.
+  lir->safepoint()->setFramePushedAtStackMapBase(masm.framePushed());
+  lir->safepoint()->setIsWasmTrap();
+}
+
+void CodeGenerator::visitWasmTrap(LWasmTrap* lir) {
+  MOZ_ASSERT(gen->compilingWasm());
+  const MWasmTrap* mir = lir->mir();
+
+  masm.wasmTrap(mir->trap(), mir->bytecodeOffset());
+}
+
+void CodeGenerator::visitWasmBoundsCheck(LWasmBoundsCheck* ins) {
+  const MWasmBoundsCheck* mir = ins->mir();
+  Register ptr = ToRegister(ins->ptr());
+  Register boundsCheckLimit = ToRegister(ins->boundsCheckLimit());
+  Label ok;
+  masm.wasmBoundsCheck32(Assembler::Below, ptr, boundsCheckLimit, &ok);
+  masm.wasmTrap(wasm::Trap::OutOfBounds, mir->bytecodeOffset());
+  masm.bind(&ok);
+}
+
+void CodeGenerator::visitWasmAlignmentCheck(LWasmAlignmentCheck* ins) {
+  const MWasmAlignmentCheck* mir = ins->mir();
+  Register ptr = ToRegister(ins->ptr());
+  Label ok;
+  masm.branchTest32(Assembler::Zero, ptr, Imm32(mir->byteSize() - 1), &ok);
+  masm.wasmTrap(wasm::Trap::UnalignedAccess, mir->bytecodeOffset());
+  masm.bind(&ok);
+}
+
+void CodeGenerator::visitWasmLoadTls(LWasmLoadTls* ins) {
+  switch (ins->mir()->type()) {
+    case MIRType::Pointer:
+      masm.loadPtr(Address(ToRegister(ins->tlsPtr()), ins->mir()->offset()),
+                   ToRegister(ins->output()));
+      break;
+    case MIRType::Int32:
+      masm.load32(Address(ToRegister(ins->tlsPtr()), ins->mir()->offset()),
+                  ToRegister(ins->output()));
+      break;
+    default:
+      MOZ_CRASH("MIRType not supported in WasmLoadTls");
+  }
+}
+
+void CodeGenerator::incrementWarmUpCounter(AbsoluteAddress warmUpCount,
+                                           JSScript* script, Register tmp) {
+  // The code depends on the JitScript* not being discarded without also
+  // invalidating Ion code. Assert this.
+#ifdef DEBUG
+  Label ok;
+  masm.movePtr(ImmGCPtr(script), tmp);
+  masm.loadJitScript(tmp, tmp);
+  masm.branchPtr(Assembler::Equal, tmp, ImmPtr(script->jitScript()), &ok);
+  masm.assumeUnreachable("Didn't find JitScript?");
+  masm.bind(&ok);
+#endif
+
+  masm.load32(warmUpCount, tmp);
+  masm.add32(Imm32(1), tmp);
+  masm.store32(tmp, warmUpCount);
+}
+
+void CodeGenerator::visitIncrementWarmUpCounter(LIncrementWarmUpCounter* ins) {
+  Register tmp = ToRegister(ins->scratch());
+
+  AbsoluteAddress warmUpCount =
+      AbsoluteAddress(ins->mir()->script()->jitScript())
+          .offset(JitScript::offsetOfWarmUpCount());
+  incrementWarmUpCounter(warmUpCount, ins->mir()->script(), tmp);
+}
+
+void CodeGenerator::visitLexicalCheck(LLexicalCheck* ins) {
+  ValueOperand inputValue = ToValue(ins, LLexicalCheck::Input);
+  Label bail;
+  masm.branchTestMagicValue(Assembler::Equal, inputValue,
+                            JS_UNINITIALIZED_LEXICAL, &bail);
+  bailoutFrom(&bail, ins->snapshot());
+}
+
+void CodeGenerator::visitThrowRuntimeLexicalError(
+    LThrowRuntimeLexicalError* ins) {
+  pushArg(Imm32(ins->mir()->errorNumber()));
+
+  using Fn = bool (*)(JSContext*, unsigned);
+  callVM<Fn, jit::ThrowRuntimeLexicalError>(ins);
+}
+
+void CodeGenerator::visitThrowMsg(LThrowMsg* ins) {
+  pushArg(Imm32(static_cast<int32_t>(ins->mir()->throwMsgKind())));
+
+  using Fn = bool (*)(JSContext*, unsigned);
+  callVM<Fn, js::ThrowMsgOperation>(ins);
+}
+
+void CodeGenerator::visitGlobalDeclInstantiation(
+    LGlobalDeclInstantiation* ins) {
+  pushArg(ImmPtr(ins->mir()->resumePoint()->pc()));
+  pushArg(ImmGCPtr(ins->mir()->block()->info().script()));
+
+  using Fn = bool (*)(JSContext*, HandleScript, jsbytecode*);
+  callVM<Fn, GlobalDeclInstantiationFromIon>(ins);
+}
+
+void CodeGenerator::visitDebugger(LDebugger* ins) {
+  Register cx = ToRegister(ins->getTemp(0));
+  Register temp = ToRegister(ins->getTemp(1));
+
+  masm.loadJSContext(cx);
+  using Fn = bool (*)(JSContext * cx);
+  masm.setupUnalignedABICall(temp);
+  masm.passABIArg(cx);
+  masm.callWithABI<Fn, GlobalHasLiveOnDebuggerStatement>();
+
+  Label bail;
+  masm.branchIfTrueBool(ReturnReg, &bail);
+  bailoutFrom(&bail, ins->snapshot());
+}
+
+void CodeGenerator::visitNewTarget(LNewTarget* ins) {
+  ValueOperand output = ToOutValue(ins);
+
+  // if (isConstructing) output = argv[Max(numActualArgs, numFormalArgs)]
+  Label notConstructing, done;
+  Address calleeToken(masm.getStackPointer(),
+                      frameSize() + JitFrameLayout::offsetOfCalleeToken());
+  masm.branchTestPtr(Assembler::Zero, calleeToken,
+                     Imm32(CalleeToken_FunctionConstructing), &notConstructing);
+
+  Register argvLen = output.scratchReg();
+
+  Address actualArgsPtr(masm.getStackPointer(),
+                        frameSize() + JitFrameLayout::offsetOfNumActualArgs());
+  masm.loadPtr(actualArgsPtr, argvLen);
+
+  Label useNFormals;
+
+  size_t numFormalArgs = ins->mirRaw()->block()->info().nargs();
+  masm.branchPtr(Assembler::Below, argvLen, Imm32(numFormalArgs), &useNFormals);
+
+  size_t argsOffset = frameSize() + JitFrameLayout::offsetOfActualArgs();
+  {
+    BaseValueIndex newTarget(masm.getStackPointer(), argvLen, argsOffset);
+    masm.loadValue(newTarget, output);
+    masm.jump(&done);
+  }
+
+  masm.bind(&useNFormals);
+
+  {
+    Address newTarget(masm.getStackPointer(),
+                      argsOffset + (numFormalArgs * sizeof(Value)));
+    masm.loadValue(newTarget, output);
+    masm.jump(&done);
+  }
+
+  // else output = undefined
+  masm.bind(&notConstructing);
+  masm.moveValue(UndefinedValue(), output);
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitCheckReturn(LCheckReturn* ins) {
+  ValueOperand returnValue = ToValue(ins, LCheckReturn::ReturnValue);
+  ValueOperand thisValue = ToValue(ins, LCheckReturn::ThisValue);
+  ValueOperand output = ToOutValue(ins);
+
+  using Fn = bool (*)(JSContext*, HandleValue);
+  OutOfLineCode* ool = oolCallVM<Fn, ThrowBadDerivedReturnOrUninitializedThis>(
+      ins, ArgList(returnValue), StoreNothing());
+
+  Label noChecks;
+  masm.branchTestObject(Assembler::Equal, returnValue, &noChecks);
+  masm.branchTestUndefined(Assembler::NotEqual, returnValue, ool->entry());
+  masm.branchTestMagic(Assembler::Equal, thisValue, ool->entry());
+  masm.moveValue(thisValue, output);
+  masm.jump(ool->rejoin());
+  masm.bind(&noChecks);
+  masm.moveValue(returnValue, output);
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCheckIsObj(LCheckIsObj* ins) {
+  ValueOperand value = ToValue(ins, LCheckIsObj::ValueIndex);
+  Register output = ToRegister(ins->output());
+
+  using Fn = bool (*)(JSContext*, CheckIsObjectKind);
+  OutOfLineCode* ool = oolCallVM<Fn, ThrowCheckIsObject>(
+      ins, ArgList(Imm32(ins->mir()->checkKind())), StoreNothing());
+
+  masm.fallibleUnboxObject(value, output, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCheckObjCoercible(LCheckObjCoercible* ins) {
+  ValueOperand checkValue = ToValue(ins, LCheckObjCoercible::CheckValue);
+
+  using Fn = bool (*)(JSContext*, HandleValue);
+  OutOfLineCode* ool = oolCallVM<Fn, ThrowObjectCoercible>(
+      ins, ArgList(checkValue), StoreNothing());
+  masm.branchTestNull(Assembler::Equal, checkValue, ool->entry());
+  masm.branchTestUndefined(Assembler::Equal, checkValue, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCheckClassHeritage(LCheckClassHeritage* ins) {
+  ValueOperand heritage = ToValue(ins, LCheckClassHeritage::Heritage);
+  Register temp = ToRegister(ins->temp());
+
+  using Fn = bool (*)(JSContext*, HandleValue);
+  OutOfLineCode* ool = oolCallVM<Fn, CheckClassHeritageOperation>(
+      ins, ArgList(heritage), StoreNothing());
+
+  masm.branchTestNull(Assembler::Equal, heritage, ool->rejoin());
+  masm.branchTestObject(Assembler::NotEqual, heritage, ool->entry());
+
+  Register object = masm.extractObject(heritage, temp);
+  masm.isConstructor(object, temp, ool->entry());
+
+  masm.branchTest32(Assembler::Zero, temp, temp, ool->entry());
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCheckThis(LCheckThis* ins) {
+  ValueOperand thisValue = ToValue(ins, LCheckThis::ThisValue);
+
+  using Fn = bool (*)(JSContext*);
+  OutOfLineCode* ool =
+      oolCallVM<Fn, ThrowUninitializedThis>(ins, ArgList(), StoreNothing());
+  masm.branchTestMagic(Assembler::Equal, thisValue, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitCheckThisReinit(LCheckThisReinit* ins) {
+  ValueOperand thisValue = ToValue(ins, LCheckThisReinit::ThisValue);
+
+  using Fn = bool (*)(JSContext*);
+  OutOfLineCode* ool =
+      oolCallVM<Fn, ThrowInitializedThis>(ins, ArgList(), StoreNothing());
+  masm.branchTestMagic(Assembler::NotEqual, thisValue, ool->entry());
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitGenerator(LGenerator* lir) {
+  Register callee = ToRegister(lir->callee());
+  Register environmentChain = ToRegister(lir->environmentChain());
+  Register argsObject = ToRegister(lir->argsObject());
+
+  pushArg(argsObject);
+  pushArg(environmentChain);
+  pushArg(ImmGCPtr(current->mir()->info().script()));
+  pushArg(callee);
+
+  using Fn = JSObject* (*)(JSContext * cx, HandleFunction, HandleScript,
+                           HandleObject, HandleObject);
+  callVM<Fn, CreateGenerator>(lir);
+}
+
+void CodeGenerator::visitAsyncResolve(LAsyncResolve* lir) {
+  Register generator = ToRegister(lir->generator());
+  ValueOperand valueOrReason = ToValue(lir, LAsyncResolve::ValueOrReasonInput);
+  AsyncFunctionResolveKind resolveKind = lir->mir()->resolveKind();
+
+  pushArg(Imm32(static_cast<int32_t>(resolveKind)));
+  pushArg(valueOrReason);
+  pushArg(generator);
+
+  using Fn = JSObject* (*)(JSContext*, Handle<AsyncFunctionGeneratorObject*>,
+                           HandleValue, AsyncFunctionResolveKind);
+  callVM<Fn, js::AsyncFunctionResolve>(lir);
+}
+
+void CodeGenerator::visitAsyncAwait(LAsyncAwait* lir) {
+  ValueOperand value = ToValue(lir, LAsyncAwait::ValueInput);
+  Register generator = ToRegister(lir->generator());
+
+  pushArg(value);
+  pushArg(generator);
+
+  using Fn = JSObject* (*)(JSContext * cx,
+                           Handle<AsyncFunctionGeneratorObject*> genObj,
+                           HandleValue value);
+  callVM<Fn, js::AsyncFunctionAwait>(lir);
+}
+
+void CodeGenerator::visitCanSkipAwait(LCanSkipAwait* lir) {
+  ValueOperand value = ToValue(lir, LCanSkipAwait::ValueInput);
+
+  pushArg(value);
+
+  using Fn = bool (*)(JSContext*, HandleValue, bool* canSkip);
+  callVM<Fn, js::CanSkipAwait>(lir);
+}
+
+void CodeGenerator::visitMaybeExtractAwaitValue(LMaybeExtractAwaitValue* lir) {
+  ValueOperand value = ToValue(lir, LMaybeExtractAwaitValue::ValueInput);
+  ValueOperand output = ToOutValue(lir);
+  Register canSkip = ToRegister(lir->canSkip());
+
+  Label cantExtract, finished;
+  masm.branchIfFalseBool(canSkip, &cantExtract);
+
+  pushArg(value);
+
+  using Fn = bool (*)(JSContext*, HandleValue, MutableHandleValue);
+  callVM<Fn, js::ExtractAwaitValue>(lir);
+  masm.jump(&finished);
+  masm.bind(&cantExtract);
+
+  masm.moveValue(value, output);
+
+  masm.bind(&finished);
+}
+
+void CodeGenerator::visitDebugCheckSelfHosted(LDebugCheckSelfHosted* ins) {
+  ValueOperand checkValue = ToValue(ins, LDebugCheckSelfHosted::CheckValue);
+  pushArg(checkValue);
+  using Fn = bool (*)(JSContext*, HandleValue);
+  callVM<Fn, js::Debug_CheckSelfHosted>(ins);
+}
+
+void CodeGenerator::visitRandom(LRandom* ins) {
+  using mozilla::non_crypto::XorShift128PlusRNG;
+
+  FloatRegister output = ToFloatRegister(ins->output());
+  Register rngReg = ToRegister(ins->temp0());
+
+  Register64 temp1 = ToRegister64(ins->temp1());
+  Register64 temp2 = ToRegister64(ins->temp2());
+
+  const XorShift128PlusRNG* rng = gen->realm->addressOfRandomNumberGenerator();
+  masm.movePtr(ImmPtr(rng), rngReg);
+
+  masm.randomDouble(rngReg, output, temp1, temp2);
+}
+
+void CodeGenerator::visitSignExtendInt32(LSignExtendInt32* ins) {
+  Register input = ToRegister(ins->input());
+  Register output = ToRegister(ins->output());
+
+  switch (ins->mode()) {
+    case MSignExtendInt32::Byte:
+      masm.move8SignExtend(input, output);
+      break;
+    case MSignExtendInt32::Half:
+      masm.move16SignExtend(input, output);
+      break;
+  }
+}
+
+void CodeGenerator::visitRotate(LRotate* ins) {
+  MRotate* mir = ins->mir();
+  Register input = ToRegister(ins->input());
+  Register dest = ToRegister(ins->output());
+
+  const LAllocation* count = ins->count();
+  if (count->isConstant()) {
+    int32_t c = ToInt32(count) & 0x1F;
+    if (mir->isLeftRotate()) {
+      masm.rotateLeft(Imm32(c), input, dest);
+    } else {
+      masm.rotateRight(Imm32(c), input, dest);
+    }
+  } else {
+    Register creg = ToRegister(count);
+    if (mir->isLeftRotate()) {
+      masm.rotateLeft(creg, input, dest);
+    } else {
+      masm.rotateRight(creg, input, dest);
+    }
+  }
+}
+
+class OutOfLineNaNToZero : public OutOfLineCodeBase<CodeGenerator> {
+  LNaNToZero* lir_;
+
+ public:
+  explicit OutOfLineNaNToZero(LNaNToZero* lir) : lir_(lir) {}
+
+  void accept(CodeGenerator* codegen) override {
+    codegen->visitOutOfLineNaNToZero(this);
+  }
+  LNaNToZero* lir() const { return lir_; }
+};
+
+void CodeGenerator::visitOutOfLineNaNToZero(OutOfLineNaNToZero* ool) {
+  FloatRegister output = ToFloatRegister(ool->lir()->output());
+  masm.loadConstantDouble(0.0, output);
+  masm.jump(ool->rejoin());
+}
+
+void CodeGenerator::visitNaNToZero(LNaNToZero* lir) {
+  FloatRegister input = ToFloatRegister(lir->input());
+
+  OutOfLineNaNToZero* ool = new (alloc()) OutOfLineNaNToZero(lir);
+  addOutOfLineCode(ool, lir->mir());
+
+  if (lir->mir()->operandIsNeverNegativeZero()) {
+    masm.branchDouble(Assembler::DoubleUnordered, input, input, ool->entry());
+  } else {
+    FloatRegister scratch = ToFloatRegister(lir->tempDouble());
+    masm.loadConstantDouble(0.0, scratch);
+    masm.branchDouble(Assembler::DoubleEqualOrUnordered, input, scratch,
+                      ool->entry());
+  }
+  masm.bind(ool->rejoin());
+}
+
+static void BoundFunctionLength(MacroAssembler& masm, Register target,
+                                Register targetFlags, Register argCount,
+                                Register output, Label* slowPath) {
+  masm.loadFunctionLength(target, targetFlags, output, slowPath);
+
+  // Compute the bound function length: Max(0, target.length - argCount).
+  Label nonNegative;
+  masm.sub32(argCount, output);
+  masm.branch32(Assembler::GreaterThanOrEqual, output, Imm32(0), &nonNegative);
+  masm.move32(Imm32(0), output);
+  masm.bind(&nonNegative);
+}
+
+static void BoundFunctionName(MacroAssembler& masm, Register target,
+                              Register targetFlags, Register output,
+                              const JSAtomState& names, Label* slowPath) {
+  Label notBoundTarget, loadName;
+  masm.branchTest32(Assembler::Zero, targetFlags,
+                    Imm32(FunctionFlags::BOUND_FUN), &notBoundTarget);
+  {
+    // Call into the VM if the target's name atom contains the bound
+    // function prefix.
+    masm.branchTest32(Assembler::NonZero, targetFlags,
+                      Imm32(FunctionFlags::HAS_BOUND_FUNCTION_NAME_PREFIX),
+                      slowPath);
+
+    // Bound functions reuse HAS_GUESSED_ATOM for
+    // HAS_BOUND_FUNCTION_NAME_PREFIX, so skip the guessed atom check below.
+    static_assert(
+        FunctionFlags::HAS_BOUND_FUNCTION_NAME_PREFIX ==
+            FunctionFlags::HAS_GUESSED_ATOM,
+        "HAS_BOUND_FUNCTION_NAME_PREFIX is shared with HAS_GUESSED_ATOM");
+    masm.jump(&loadName);
+  }
+  masm.bind(&notBoundTarget);
+
+  Label guessed, hasName;
+  masm.branchTest32(Assembler::NonZero, targetFlags,
+                    Imm32(FunctionFlags::HAS_GUESSED_ATOM), &guessed);
+  masm.bind(&loadName);
+  masm.loadPtr(Address(target, JSFunction::offsetOfAtom()), output);
+  masm.branchTestPtr(Assembler::NonZero, output, output, &hasName);
+  {
+    masm.bind(&guessed);
+
+    // An absent name property defaults to the empty string.
+    masm.movePtr(ImmGCPtr(names.empty), output);
+  }
+  masm.bind(&hasName);
+}
+
+static void BoundFunctionFlags(MacroAssembler& masm, Register targetFlags,
+                               Register bound, Register output) {
+  // Set the BOUND_FN flag and, if the target is a constructor, the
+  // CONSTRUCTOR flag.
+  Label isConstructor, boundFlagsComputed;
+  masm.load16ZeroExtend(Address(bound, JSFunction::offsetOfFlags()), output);
+  masm.branchTest32(Assembler::NonZero, targetFlags,
+                    Imm32(FunctionFlags::CONSTRUCTOR), &isConstructor);
+  {
+    masm.or32(Imm32(FunctionFlags::BOUND_FUN), output);
+    masm.jump(&boundFlagsComputed);
+  }
+  masm.bind(&isConstructor);
+  {
+    masm.or32(Imm32(FunctionFlags::BOUND_FUN | FunctionFlags::CONSTRUCTOR),
+              output);
+  }
+  masm.bind(&boundFlagsComputed);
+}
+
+void CodeGenerator::visitFinishBoundFunctionInit(
+    LFinishBoundFunctionInit* lir) {
+  Register bound = ToRegister(lir->bound());
+  Register target = ToRegister(lir->target());
+  Register argCount = ToRegister(lir->argCount());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+
+  using Fn = bool (*)(JSContext * cx, HandleFunction bound, HandleObject target,
+                      int32_t argCount);
+  OutOfLineCode* ool = oolCallVM<Fn, JSFunction::finishBoundFunctionInit>(
+      lir, ArgList(bound, target, argCount), StoreNothing());
+  Label* slowPath = ool->entry();
+
+  const size_t boundLengthOffset =
+      FunctionExtended::offsetOfBoundFunctionLengthSlot();
+
+  // Take the slow path if the target is not a JSFunction.
+  masm.branchTestObjClass(Assembler::NotEqual, target, &JSFunction::class_,
+                          temp1, target, slowPath);
+
+  // Take the slow path if we'd need to adjust the [[Prototype]].
+  masm.loadObjProto(bound, temp1);
+  masm.loadObjProto(target, temp2);
+  masm.branchPtr(Assembler::NotEqual, temp1, temp2, slowPath);
+
+  // Get the function flags.
+  masm.load16ZeroExtend(Address(target, JSFunction::offsetOfFlags()), temp1);
+
+  // Functions with a SelfHostedLazyScript must be compiled with the slow-path
+  // before the function length is known. If the length or name property is
+  // resolved, it might be shadowed.
+  masm.branchTest32(
+      Assembler::NonZero, temp1,
+      Imm32(FunctionFlags::SELFHOSTLAZY | FunctionFlags::RESOLVED_NAME |
+            FunctionFlags::RESOLVED_LENGTH),
+      slowPath);
+
+  // Store the bound function's length into the extended slot.
+  BoundFunctionLength(masm, target, temp1, argCount, temp2, slowPath);
+  masm.storeValue(JSVAL_TYPE_INT32, temp2, Address(bound, boundLengthOffset));
+
+  // Store the target's name atom in the bound function as is.
+  BoundFunctionName(masm, target, temp1, temp2, gen->runtime->names(),
+                    slowPath);
+  masm.storePtr(temp2, Address(bound, JSFunction::offsetOfAtom()));
+
+  // Update the bound function's flags.
+  BoundFunctionFlags(masm, temp1, bound, temp2);
+  masm.store16(temp2, Address(bound, JSFunction::offsetOfFlags()));
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitIsPackedArray(LIsPackedArray* lir) {
+  Register obj = ToRegister(lir->object());
+  Register output = ToRegister(lir->output());
+  Register temp = ToRegister(lir->temp());
+
+  masm.setIsPackedArray(obj, output, temp);
+}
+
+void CodeGenerator::visitGuardArrayIsPacked(LGuardArrayIsPacked* lir) {
+  Register array = ToRegister(lir->array());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+
+  Label bail;
+  masm.branchArrayIsNotPacked(array, temp1, temp2, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGetPrototypeOf(LGetPrototypeOf* lir) {
+  Register target = ToRegister(lir->target());
+  ValueOperand out = ToOutValue(lir);
+  Register scratch = out.scratchReg();
+
+  using Fn = bool (*)(JSContext*, HandleObject, MutableHandleValue);
+  OutOfLineCode* ool = oolCallVM<Fn, jit::GetPrototypeOf>(lir, ArgList(target),
+                                                          StoreValueTo(out));
+
+  MOZ_ASSERT(uintptr_t(TaggedProto::LazyProto) == 1);
+
+  masm.loadObjProto(target, scratch);
+
+  Label hasProto;
+  masm.branchPtr(Assembler::Above, scratch, ImmWord(1), &hasProto);
+
+  // Call into the VM for lazy prototypes.
+  masm.branchPtr(Assembler::Equal, scratch, ImmWord(1), ool->entry());
+
+  masm.moveValue(NullValue(), out);
+  masm.jump(ool->rejoin());
+
+  masm.bind(&hasProto);
+  masm.tagValue(JSVAL_TYPE_OBJECT, scratch, out);
+
+  masm.bind(ool->rejoin());
+}
+
+void CodeGenerator::visitObjectWithProto(LObjectWithProto* lir) {
+  pushArg(ToValue(lir, LObjectWithProto::PrototypeValue));
+
+  using Fn = PlainObject* (*)(JSContext*, HandleValue);
+  callVM<Fn, js::ObjectWithProtoOperation>(lir);
+}
+
+void CodeGenerator::visitObjectStaticProto(LObjectStaticProto* lir) {
+  Register obj = ToRegister(lir->input());
+  Register output = ToRegister(lir->output());
+
+  masm.loadObjProto(obj, output);
+
+#ifdef DEBUG
+  // We shouldn't encounter a null or lazy proto.
+  MOZ_ASSERT(uintptr_t(TaggedProto::LazyProto) == 1);
+
+  Label done;
+  masm.branchPtr(Assembler::Above, output, ImmWord(1), &done);
+  masm.assumeUnreachable("Unexpected null or lazy proto in MObjectStaticProto");
+  masm.bind(&done);
+#endif
+}
+
+void CodeGenerator::visitBuiltinObject(LBuiltinObject* lir) {
+  pushArg(Imm32(static_cast<int32_t>(lir->mir()->builtinObjectKind())));
+
+  using Fn = JSObject* (*)(JSContext*, BuiltinObjectKind);
+  callVM<Fn, js::BuiltinObjectOperation>(lir);
+}
+
+void CodeGenerator::visitSuperFunction(LSuperFunction* lir) {
+  Register callee = ToRegister(lir->callee());
+  ValueOperand out = ToOutValue(lir);
+  Register temp = ToRegister(lir->temp());
+
+#ifdef DEBUG
+  Label classCheckDone;
+  masm.branchTestObjClass(Assembler::Equal, callee, &JSFunction::class_, temp,
+                          callee, &classCheckDone);
+  masm.assumeUnreachable("Unexpected non-JSFunction callee in JSOp::SuperFun");
+  masm.bind(&classCheckDone);
+#endif
+
+  // Load prototype of callee
+  masm.loadObjProto(callee, temp);
+
+#ifdef DEBUG
+  // We won't encounter a lazy proto, because |callee| is guaranteed to be a
+  // JSFunction and only proxy objects can have a lazy proto.
+  MOZ_ASSERT(uintptr_t(TaggedProto::LazyProto) == 1);
+
+  Label proxyCheckDone;
+  masm.branchPtr(Assembler::NotEqual, temp, ImmWord(1), &proxyCheckDone);
+  masm.assumeUnreachable("Unexpected lazy proto in JSOp::SuperFun");
+  masm.bind(&proxyCheckDone);
+#endif
+
+  Label nullProto, done;
+  masm.branchPtr(Assembler::Equal, temp, ImmWord(0), &nullProto);
+
+  // Box prototype and return
+  masm.tagValue(JSVAL_TYPE_OBJECT, temp, out);
+  masm.jump(&done);
+
+  masm.bind(&nullProto);
+  masm.moveValue(NullValue(), out);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitInitHomeObject(LInitHomeObject* lir) {
+  Register func = ToRegister(lir->function());
+  ValueOperand homeObject = ToValue(lir, LInitHomeObject::HomeObjectValue);
+
+  Address addr(func, FunctionExtended::offsetOfMethodHomeObjectSlot());
+
+  emitPreBarrier(addr);
+  masm.storeValue(homeObject, addr);
+}
+
+void CodeGenerator::visitIsTypedArrayConstructor(
+    LIsTypedArrayConstructor* lir) {
+  Register object = ToRegister(lir->object());
+  Register output = ToRegister(lir->output());
+
+  masm.setIsDefinitelyTypedArrayConstructor(object, output);
+}
+
+void CodeGenerator::visitLoadValueTag(LLoadValueTag* lir) {
+  ValueOperand value = ToValue(lir, LLoadValueTag::Value);
+  Register output = ToRegister(lir->output());
+
+  Register tag = masm.extractTag(value, output);
+  if (tag != output) {
+    masm.mov(tag, output);
+  }
+}
+
+void CodeGenerator::visitGuardTagNotEqual(LGuardTagNotEqual* lir) {
+  Register lhs = ToRegister(lir->lhs());
+  Register rhs = ToRegister(lir->rhs());
+
+  bailoutCmp32(Assembler::Equal, lhs, rhs, lir->snapshot());
+
+  // If both lhs and rhs are numbers, can't use tag comparison to do inequality
+  // comparison
+  Label done;
+  masm.branchTestNumber(Assembler::NotEqual, lhs, &done);
+  masm.branchTestNumber(Assembler::NotEqual, rhs, &done);
+  bailout(lir->snapshot());
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitLoadWrapperTarget(LLoadWrapperTarget* lir) {
+  Register object = ToRegister(lir->object());
+  Register output = ToRegister(lir->output());
+
+  masm.loadPtr(Address(object, ProxyObject::offsetOfReservedSlots()), output);
+  masm.unboxObject(
+      Address(output, js::detail::ProxyReservedSlots::offsetOfPrivateSlot()),
+      output);
+}
+
+void CodeGenerator::visitGuardHasGetterSetter(LGuardHasGetterSetter* lir) {
+  Register object = ToRegister(lir->object());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+
+  masm.movePtr(ImmGCPtr(lir->mir()->shape()), temp2);
+
+  using Fn = bool (*)(JSContext * cx, JSObject * obj, Shape * propShape);
+  masm.setupUnalignedABICall(temp1);
+  masm.loadJSContext(temp1);
+  masm.passABIArg(temp1);
+  masm.passABIArg(object);
+  masm.passABIArg(temp2);
+  masm.callWithABI<Fn, ObjectHasGetterSetterPure>();
+
+  bailoutIfFalseBool(ReturnReg, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardIsExtensible(LGuardIsExtensible* lir) {
+  Register object = ToRegister(lir->object());
+  Register temp = ToRegister(lir->temp());
+
+  Label bail;
+  masm.branchIfObjectNotExtensible(object, temp, &bail);
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitGuardInt32IsNonNegative(
+    LGuardInt32IsNonNegative* lir) {
+  Register index = ToRegister(lir->index());
+
+  bailoutCmp32(Assembler::LessThan, index, Imm32(0), lir->snapshot());
+}
+
+void CodeGenerator::visitGuardIndexGreaterThanDenseInitLength(
+    LGuardIndexGreaterThanDenseInitLength* lir) {
+  Register object = ToRegister(lir->object());
+  Register index = ToRegister(lir->index());
+  Register temp = ToRegister(lir->temp());
+  Register spectreTemp = ToTempRegisterOrInvalid(lir->spectreTemp());
+
+  // Load obj->elements.
+  masm.loadPtr(Address(object, NativeObject::offsetOfElements()), temp);
+
+  // Ensure index >= initLength.
+  Label outOfBounds;
+  Address capacity(temp, ObjectElements::offsetOfInitializedLength());
+  masm.spectreBoundsCheck32(index, capacity, spectreTemp, &outOfBounds);
+  bailout(lir->snapshot());
+  masm.bind(&outOfBounds);
+}
+
+void CodeGenerator::visitGuardIndexIsValidUpdateOrAdd(
+    LGuardIndexIsValidUpdateOrAdd* lir) {
+  Register object = ToRegister(lir->object());
+  Register index = ToRegister(lir->index());
+  Register temp = ToRegister(lir->temp());
+  Register spectreTemp = ToTempRegisterOrInvalid(lir->spectreTemp());
+
+  // Load obj->elements.
+  masm.loadPtr(Address(object, NativeObject::offsetOfElements()), temp);
+
+  Label success;
+
+  // If length is writable, branch to &success.  All indices are writable.
+  Address flags(temp, ObjectElements::offsetOfFlags());
+  masm.branchTest32(Assembler::Zero, flags,
+                    Imm32(ObjectElements::Flags::NONWRITABLE_ARRAY_LENGTH),
+                    &success);
+
+  // Otherwise, ensure index is in bounds.
+  Label bail;
+  Address length(temp, ObjectElements::offsetOfLength());
+  masm.spectreBoundsCheck32(index, length, spectreTemp, &bail);
+  masm.bind(&success);
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitCallAddOrUpdateSparseElement(
+    LCallAddOrUpdateSparseElement* lir) {
+  Register object = ToRegister(lir->object());
+  Register index = ToRegister(lir->index());
+  ValueOperand value = ToValue(lir, LCallAddOrUpdateSparseElement::ValueIndex);
+
+  pushArg(Imm32(lir->mir()->strict()));
+  pushArg(value);
+  pushArg(index);
+  pushArg(object);
+
+  using Fn =
+      bool (*)(JSContext*, HandleArrayObject, int32_t, HandleValue, bool);
+  callVM<Fn, js::AddOrUpdateSparseElementHelper>(lir);
+}
+
+void CodeGenerator::visitCallGetSparseElement(LCallGetSparseElement* lir) {
+  Register object = ToRegister(lir->object());
+  Register index = ToRegister(lir->index());
+
+  pushArg(index);
+  pushArg(object);
+
+  using Fn =
+      bool (*)(JSContext*, HandleArrayObject, int32_t, MutableHandleValue);
+  callVM<Fn, js::GetSparseElementHelper>(lir);
+}
+
+void CodeGenerator::visitCallNativeGetElement(LCallNativeGetElement* lir) {
+  Register object = ToRegister(lir->object());
+  Register index = ToRegister(lir->index());
+
+  pushArg(index);
+  pushArg(TypedOrValueRegister(MIRType::Object, AnyRegister(object)));
+  pushArg(object);
+
+  using Fn = bool (*)(JSContext*, HandleNativeObject, HandleValue, int32_t,
+                      MutableHandleValue);
+  callVM<Fn, js::NativeGetElement>(lir);
+}
+
+void CodeGenerator::visitCallObjectHasSparseElement(
+    LCallObjectHasSparseElement* lir) {
+  Register object = ToRegister(lir->object());
+  Register index = ToRegister(lir->index());
+  Register temp1 = ToRegister(lir->temp1());
+  Register temp2 = ToRegister(lir->temp2());
+  Register output = ToRegister(lir->output());
+
+  masm.reserveStack(sizeof(Value));
+  masm.moveStackPtrTo(temp2);
+
+  using Fn = bool (*)(JSContext*, NativeObject*, int32_t, Value*);
+  masm.setupUnalignedABICall(temp1);
+  masm.loadJSContext(temp1);
+  masm.passABIArg(temp1);
+  masm.passABIArg(object);
+  masm.passABIArg(index);
+  masm.passABIArg(temp2);
+  masm.callWithABI<Fn, HasNativeElementPure>();
+  masm.mov(ReturnReg, temp1);
+
+  Label bail, ok;
+  uint32_t framePushed = masm.framePushed();
+  masm.branchIfTrueBool(temp1, &ok);
+  masm.adjustStack(sizeof(Value));
+  masm.jump(&bail);
+
+  masm.bind(&ok);
+  masm.setFramePushed(framePushed);
+  masm.unboxBoolean(Address(masm.getStackPointer(), 0), output);
+  masm.adjustStack(sizeof(Value));
+
+  bailoutFrom(&bail, lir->snapshot());
+}
+
+void CodeGenerator::visitBigIntAsIntN(LBigIntAsIntN* ins) {
+  Register bits = ToRegister(ins->bits());
+  Register input = ToRegister(ins->input());
+
+  pushArg(bits);
+  pushArg(input);
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, int32_t);
+  callVM<Fn, jit::BigIntAsIntN>(ins);
+}
+
+void CodeGenerator::visitBigIntAsIntN64(LBigIntAsIntN64* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp = ToRegister(ins->temp());
+  Register64 temp64 = ToRegister64(ins->temp64());
+  Register output = ToRegister(ins->output());
+
+  Label done, create;
+
+  masm.movePtr(input, output);
+
+  // Load the BigInt value as an int64.
+  masm.loadBigInt64(input, temp64);
+
+  // Create a new BigInt when the input exceeds the int64 range.
+  masm.branch32(Assembler::Above, Address(input, BigInt::offsetOfLength()),
+                Imm32(64 / BigInt::DigitBits), &create);
+
+  // And create a new BigInt when the value and the BigInt have different signs.
+  Label nonNegative;
+  masm.branchIfBigIntIsNonNegative(input, &nonNegative);
+  masm.branchTest64(Assembler::NotSigned, temp64, temp64, temp, &create);
+  masm.jump(&done);
+
+  masm.bind(&nonNegative);
+  masm.branchTest64(Assembler::NotSigned, temp64, temp64, temp, &done);
+
+  masm.bind(&create);
+  emitCreateBigInt(ins, Scalar::BigInt64, temp64, output, temp);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitBigIntAsIntN32(LBigIntAsIntN32* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp = ToRegister(ins->temp());
+  Register64 temp64 = ToRegister64(ins->temp64());
+  Register output = ToRegister(ins->output());
+
+  Label done, create;
+
+  masm.movePtr(input, output);
+
+  // Load the absolute value of the first digit.
+  masm.loadFirstBigIntDigitOrZero(input, temp);
+
+  // If the absolute value exceeds the int32 range, create a new BigInt.
+  masm.branchPtr(Assembler::Above, temp, Imm32(INT32_MAX), &create);
+
+  // Also create a new BigInt if we have more than one digit.
+  masm.branch32(Assembler::BelowOrEqual,
+                Address(input, BigInt::offsetOfLength()), Imm32(1), &done);
+
+  masm.bind(&create);
+
+  // |temp| stores the absolute value, negate it when the sign flag is set.
+  Label nonNegative;
+  masm.branchIfBigIntIsNonNegative(input, &nonNegative);
+  masm.negPtr(temp);
+  masm.bind(&nonNegative);
+
+  masm.move32To64SignExtend(temp, temp64);
+  emitCreateBigInt(ins, Scalar::BigInt64, temp64, output, temp);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitBigIntAsUintN(LBigIntAsUintN* ins) {
+  Register bits = ToRegister(ins->bits());
+  Register input = ToRegister(ins->input());
+
+  pushArg(bits);
+  pushArg(input);
+
+  using Fn = BigInt* (*)(JSContext*, HandleBigInt, int32_t);
+  callVM<Fn, jit::BigIntAsUintN>(ins);
+}
+
+void CodeGenerator::visitBigIntAsUintN64(LBigIntAsUintN64* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp = ToRegister(ins->temp());
+  Register64 temp64 = ToRegister64(ins->temp64());
+  Register output = ToRegister(ins->output());
+
+  Label done, create;
+
+  masm.movePtr(input, output);
+
+  // Load the BigInt value as an uint64.
+  masm.loadBigInt64(input, temp64);
+
+  // Create a new BigInt when the input exceeds the uint64 range.
+  masm.branch32(Assembler::Above, Address(input, BigInt::offsetOfLength()),
+                Imm32(64 / BigInt::DigitBits), &create);
+
+  // And create a new BigInt when the input has the sign flag set.
+  masm.branchIfBigIntIsNonNegative(input, &done);
+
+  masm.bind(&create);
+  emitCreateBigInt(ins, Scalar::BigUint64, temp64, output, temp);
+
+  masm.bind(&done);
+}
+
+void CodeGenerator::visitBigIntAsUintN32(LBigIntAsUintN32* ins) {
+  Register input = ToRegister(ins->input());
+  Register temp = ToRegister(ins->temp());
+  Register64 temp64 = ToRegister64(ins->temp64());
+  Register output = ToRegister(ins->output());
+
+  Label done, create;
+
+  masm.movePtr(input, output);
+
+  // Load the absolute value of the first digit.
+  masm.loadFirstBigIntDigitOrZero(input, temp);
+
+  // If the absolute value exceeds the uint32 range, create a new BigInt.
+#if JS_PUNBOX64
+  masm.branchPtr(Assembler::Above, temp, ImmWord(UINT32_MAX), &create);
+#endif
+
+  // Also create a new BigInt if we have more than one digit.
+  masm.branch32(Assembler::Above, Address(input, BigInt::offsetOfLength()),
+                Imm32(1), &create);
+
+  // And create a new BigInt when the input has the sign flag set.
+  masm.branchIfBigIntIsNonNegative(input, &done);
+
+  masm.bind(&create);
+
+  // |temp| stores the absolute value, negate it when the sign flag is set.
+  Label nonNegative;
+  masm.branchIfBigIntIsNonNegative(input, &nonNegative);
+  masm.negPtr(temp);
+  masm.bind(&nonNegative);
+
+  masm.move32To64ZeroExtend(temp, temp64);
+  emitCreateBigInt(ins, Scalar::BigUint64, temp64, output, temp);
+
+  masm.bind(&done);
+}
+
+template <size_t NumDefs>
+void CodeGenerator::emitIonToWasmCallBase(LIonToWasmCallBase<NumDefs>* lir) {
+  wasm::JitCallStackArgVector stackArgs;
+  masm.propagateOOM(stackArgs.reserve(lir->numOperands()));
+  if (masm.oom()) {
+    return;
+  }
+
+  const wasm::FuncExport& funcExport = lir->mir()->funcExport();
+  const wasm::FuncType& sig = funcExport.funcType();
+
+  WasmABIArgGenerator abi;
+  for (size_t i = 0; i < lir->numOperands(); i++) {
+    MIRType argMir;
+    switch (sig.args()[i].kind()) {
+      case wasm::ValType::I32:
+      case wasm::ValType::I64:
+      case wasm::ValType::F32:
+      case wasm::ValType::F64:
+        argMir = ToMIRType(sig.args()[i]);
+        break;
+      case wasm::ValType::V128:
+        MOZ_CRASH("unexpected argument type when calling from ion to wasm");
+      case wasm::ValType::Ref:
+        switch (sig.args()[i].refTypeKind()) {
+          case wasm::RefType::Extern:
+            // AnyRef is boxed on the JS side, so passed as a pointer here.
+            argMir = ToMIRType(sig.args()[i]);
+            break;
+          case wasm::RefType::Func:
+          case wasm::RefType::Eq:
+          case wasm::RefType::TypeIndex:
+            MOZ_CRASH("unexpected argument type when calling from ion to wasm");
+        }
+        break;
+    }
+
+    ABIArg arg = abi.next(argMir);
+    switch (arg.kind()) {
+      case ABIArg::GPR:
+      case ABIArg::FPU: {
+        MOZ_ASSERT(ToAnyRegister(lir->getOperand(i)) == arg.reg());
+        stackArgs.infallibleEmplaceBack(wasm::JitCallStackArg());
+        break;
+      }
+      case ABIArg::Stack: {
+        const LAllocation* larg = lir->getOperand(i);
+        if (larg->isConstant()) {
+          stackArgs.infallibleEmplaceBack(ToInt32(larg));
+        } else if (larg->isGeneralReg()) {
+          stackArgs.infallibleEmplaceBack(ToRegister(larg));
+        } else if (larg->isFloatReg()) {
+          stackArgs.infallibleEmplaceBack(ToFloatRegister(larg));
+        } else {
+          stackArgs.infallibleEmplaceBack(ToAddress(larg));
+        }
+        break;
+      }
+#ifdef JS_CODEGEN_REGISTER_PAIR
+      case ABIArg::GPR_PAIR: {
+        MOZ_CRASH(
+            "no way to pass i64, and wasm uses hardfp for function calls");
+      }
+#endif
+      case ABIArg::Uninitialized: {
+        MOZ_CRASH("Uninitialized ABIArg kind");
+      }
+    }
+  }
+
+  const wasm::ValTypeVector& results = sig.results();
+  if (results.length() == 0) {
+    MOZ_ASSERT(lir->mir()->type() == MIRType::Value);
+  } else {
+    MOZ_ASSERT(results.length() == 1, "multi-value return unimplemented");
+    switch (results[0].kind()) {
+      case wasm::ValType::I32:
+        MOZ_ASSERT(lir->mir()->type() == MIRType::Int32);
+        MOZ_ASSERT(ToRegister(lir->output()) == ReturnReg);
+        break;
+      case wasm::ValType::I64:
+        MOZ_ASSERT(lir->mir()->type() == MIRType::Int64);
+        MOZ_ASSERT(ToOutRegister64(lir) == ReturnReg64);
+        break;
+      case wasm::ValType::F32:
+        MOZ_ASSERT(lir->mir()->type() == MIRType::Float32);
+        MOZ_ASSERT(ToFloatRegister(lir->output()) == ReturnFloat32Reg);
+        break;
+      case wasm::ValType::F64:
+        MOZ_ASSERT(lir->mir()->type() == MIRType::Double);
+        MOZ_ASSERT(ToFloatRegister(lir->output()) == ReturnDoubleReg);
+        break;
+      case wasm::ValType::V128:
+        MOZ_CRASH("unexpected return type when calling from ion to wasm");
+      case wasm::ValType::Ref:
+        switch (results[0].refTypeKind()) {
+          case wasm::RefType::Func:
+          case wasm::RefType::Extern:
+          case wasm::RefType::Eq:
+            // The wasm stubs layer unboxes anything that needs to be unboxed
+            // and leaves it in a Value.  A FuncRef/EqRef we could in principle
+            // leave it as a raw object pointer but for now it complicates the
+            // API to do so.
+            MOZ_ASSERT(lir->mir()->type() == MIRType::Value);
+            break;
+          case wasm::RefType::TypeIndex:
+            MOZ_CRASH("unexpected return type when calling from ion to wasm");
+        }
+        break;
+    }
+  }
+
+  bool profilingEnabled = isProfilerInstrumentationEnabled();
+  WasmInstanceObject* instObj = lir->mir()->instanceObject();
+
+  Register scratch = ToRegister(lir->temp());
+
+  uint32_t callOffset;
+  GenerateDirectCallFromJit(masm, funcExport, instObj->instance(), stackArgs,
+                            profilingEnabled, scratch, &callOffset);
+
+  // Add the instance object to the constant pool, so it is transferred to
+  // the owning IonScript and so that it gets traced as long as the IonScript
+  // lives.
+
+  uint32_t unused;
+  masm.propagateOOM(graph.addConstantToPool(ObjectValue(*instObj), &unused));
+
+  markSafepointAt(callOffset, lir);
+}
+
+void CodeGenerator::visitIonToWasmCall(LIonToWasmCall* lir) {
+  emitIonToWasmCallBase(lir);
+}
+void CodeGenerator::visitIonToWasmCallV(LIonToWasmCallV* lir) {
+  emitIonToWasmCallBase(lir);
+}
+void CodeGenerator::visitIonToWasmCallI64(LIonToWasmCallI64* lir) {
+  emitIonToWasmCallBase(lir);
+}
+
+void CodeGenerator::visitWasmNullConstant(LWasmNullConstant* lir) {
+  masm.xorPtr(ToRegister(lir->output()), ToRegister(lir->output()));
+}
+
+void CodeGenerator::visitWasmCompareAndSelect(LWasmCompareAndSelect* ins) {
+  bool cmpIs32bit = ins->compareType() == MCompare::Compare_Int32 ||
+                    ins->compareType() == MCompare::Compare_UInt32;
+  bool selIs32bit = ins->mir()->type() == MIRType::Int32;
+
+  if (cmpIs32bit && selIs32bit) {
+    Register out = ToRegister(ins->output());
+    MOZ_ASSERT(ToRegister(ins->ifTrueExpr()) == out,
+               "true expr input is reused for output");
+
+    Assembler::Condition cond = Assembler::InvertCondition(
+        JSOpToCondition(ins->compareType(), ins->jsop()));
+    const LAllocation* rhs = ins->rightExpr();
+    const LAllocation* falseExpr = ins->ifFalseExpr();
+    Register lhs = ToRegister(ins->leftExpr());
+
+    if (rhs->isRegister()) {
+      if (falseExpr->isRegister()) {
+        // On arm32, this is the only one of the four cases that can actually
+        // happen, since |rhs| and |falseExpr| are marked useAny() by
+        // LIRGenerator::visitWasmSelect, and useAny() means "register only"
+        // on arm32.
+        masm.cmp32Move32(cond, lhs, ToRegister(rhs), ToRegister(falseExpr),
+                         out);
+      } else {
+        masm.cmp32Load32(cond, lhs, ToRegister(rhs), ToAddress(falseExpr), out);
+      }
+    } else {
+      if (falseExpr->isRegister()) {
+        masm.cmp32Move32(cond, lhs, ToAddress(rhs), ToRegister(falseExpr), out);
+      } else {
+        masm.cmp32Load32(cond, lhs, ToAddress(rhs), ToAddress(falseExpr), out);
+      }
+    }
+    return;
+  }
+
+  MOZ_CRASH("in CodeGenerator::visitWasmCompareAndSelect: unexpected types");
+}
+
+void CodeGenerator::visitWasmFence(LWasmFence* lir) {
+  MOZ_ASSERT(gen->compilingWasm());
+  masm.memoryBarrier(MembarFull);
+}
+
+void CodeGenerator::visitWasmBoxValue(LWasmBoxValue* lir) {
+  ValueOperand input = ToValue(lir, LWasmBoxValue::Input);
+  Register output = ToRegister(lir->output());
+
+  Label nullValue, objectValue, done;
+  {
+    ScratchTagScope tag(masm, input);
+    masm.splitTagForTest(input, tag);
+    masm.branchTestObject(Assembler::Equal, tag, &objectValue);
+    masm.branchTestNull(Assembler::Equal, tag, &nullValue);
+  }
+
+  using Fn = JSObject* (*)(JSContext*, HandleValue);
+  OutOfLineCode* oolBoxValue = oolCallVM<Fn, wasm::BoxBoxableValue>(
+      lir, ArgList(input), StoreRegisterTo(output));
+
+  masm.jump(oolBoxValue->entry());
+
+  masm.bind(&nullValue);
+  // See the definition of AnyRef for a discussion of pointer representation.
+  masm.xorPtr(output, output);
+  masm.jump(&done);
+
+  masm.bind(&objectValue);
+  // See the definition of AnyRef for a discussion of pointer representation.
+  masm.unboxObject(input, output);
+
+  masm.bind(&done);
+  masm.bind(oolBoxValue->rejoin());
+}
+
+void CodeGenerator::visitWasmAnyRefFromJSObject(LWasmAnyRefFromJSObject* lir) {
+  Register input = ToRegister(lir->getOperand(LWasmAnyRefFromJSObject::Input));
+  Register output = ToRegister(lir->output());
+  // See the definition of AnyRef for a discussion of pointer representation.
+  if (input != output) {
+    masm.movePtr(input, output);
+  }
+}
+
+static_assert(!std::is_polymorphic_v<CodeGenerator>,
+              "CodeGenerator should not have any virtual methods");
+
+}  // namespace jit
+}  // namespace js