Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 894 insertions, 0 deletions

diff --git a/js/src/jit/shared/Lowering-shared-inl.h b/js/src/jit/shared/Lowering-shared-inl.h
new file mode 100644
index 0000000000..89aafa22e4
--- /dev/null
+++ b/js/src/jit/shared/Lowering-shared-inl.h
@@ -0,0 +1,894 @@
+/* -*- 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/. */
+
+#ifndef jit_shared_Lowering_shared_inl_h
+#define jit_shared_Lowering_shared_inl_h
+
+#include "jit/shared/Lowering-shared.h"
+
+#include "jit/MIR.h"
+#include "jit/MIRGenerator.h"
+
+namespace js {
+namespace jit {
+
+void LIRGeneratorShared::emitAtUses(MInstruction* mir) {
+  MOZ_ASSERT(mir->canEmitAtUses());
+  mir->setEmittedAtUses();
+  mir->setVirtualRegister(0);
+}
+
+LUse LIRGeneratorShared::use(MDefinition* mir, LUse policy) {
+  // It is illegal to call use() on an instruction with two defs.
+#if BOX_PIECES > 1
+  MOZ_ASSERT(mir->type() != MIRType::Value);
+#endif
+#if INT64_PIECES > 1
+  MOZ_ASSERT(mir->type() != MIRType::Int64);
+#endif
+  ensureDefined(mir);
+  policy.setVirtualRegister(mir->virtualRegister());
+  return policy;
+}
+
+template <size_t X>
+void LIRGeneratorShared::define(
+    details::LInstructionFixedDefsTempsHelper<1, X>* lir, MDefinition* mir,
+    LDefinition::Policy policy) {
+  LDefinition::Type type = LDefinition::TypeFrom(mir->type());
+  define(lir, mir, LDefinition(type, policy));
+}
+
+template <size_t X>
+void LIRGeneratorShared::define(
+    details::LInstructionFixedDefsTempsHelper<1, X>* lir, MDefinition* mir,
+    const LDefinition& def) {
+  // Call instructions should use defineReturn.
+  MOZ_ASSERT(!lir->isCall());
+
+  uint32_t vreg = getVirtualRegister();
+
+  // Assign the definition and a virtual register. Then, propagate this
+  // virtual register to the MIR, so we can map MIR to LIR during lowering.
+  lir->setDef(0, def);
+  lir->getDef(0)->setVirtualRegister(vreg);
+  lir->setMir(mir);
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+template <size_t X, size_t Y>
+void LIRGeneratorShared::defineFixed(LInstructionHelper<1, X, Y>* lir,
+                                     MDefinition* mir,
+                                     const LAllocation& output) {
+  LDefinition::Type type = LDefinition::TypeFrom(mir->type());
+
+  LDefinition def(type, LDefinition::FIXED);
+  def.setOutput(output);
+
+  define(lir, mir, def);
+}
+
+template <size_t Ops, size_t Temps>
+void LIRGeneratorShared::defineInt64Fixed(
+    LInstructionHelper<INT64_PIECES, Ops, Temps>* lir, MDefinition* mir,
+    const LInt64Allocation& output) {
+  uint32_t vreg = getVirtualRegister();
+
+#if JS_BITS_PER_WORD == 64
+  LDefinition def(LDefinition::GENERAL, LDefinition::FIXED);
+  def.setOutput(output.value());
+  lir->setDef(0, def);
+  lir->getDef(0)->setVirtualRegister(vreg);
+#else
+  LDefinition def0(LDefinition::GENERAL, LDefinition::FIXED);
+  def0.setOutput(output.low());
+  lir->setDef(0, def0);
+  lir->getDef(0)->setVirtualRegister(vreg);
+
+  getVirtualRegister();
+  LDefinition def1(LDefinition::GENERAL, LDefinition::FIXED);
+  def1.setOutput(output.high());
+  lir->setDef(1, def1);
+  lir->getDef(1)->setVirtualRegister(vreg + 1);
+#endif
+
+  lir->setMir(mir);
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+template <size_t Ops, size_t Temps>
+void LIRGeneratorShared::defineReuseInput(
+    LInstructionHelper<1, Ops, Temps>* lir, MDefinition* mir,
+    uint32_t operand) {
+  // Note: Any other operand that is not the same as this operand should be
+  // marked as not being "atStart". The regalloc cannot handle those and can
+  // overwrite the inputs!
+
+  // The input should be used at the start of the instruction, to avoid moves.
+  MOZ_ASSERT(lir->getOperand(operand)->toUse()->usedAtStart());
+
+  LDefinition::Type type = LDefinition::TypeFrom(mir->type());
+
+  LDefinition def(type, LDefinition::MUST_REUSE_INPUT);
+  def.setReusedInput(operand);
+
+  define(lir, mir, def);
+}
+
+template <size_t Ops, size_t Temps>
+void LIRGeneratorShared::defineInt64ReuseInput(
+    LInstructionHelper<INT64_PIECES, Ops, Temps>* lir, MDefinition* mir,
+    uint32_t operand) {
+  // Note: Any other operand that is not the same as this operand should be
+  // marked as not being "atStart". The regalloc cannot handle those and can
+  // overwrite the inputs!
+
+  // The input should be used at the start of the instruction, to avoid moves.
+  MOZ_ASSERT(lir->getOperand(operand)->toUse()->usedAtStart());
+#if JS_BITS_PER_WORD == 32
+  MOZ_ASSERT(lir->getOperand(operand + 1)->toUse()->usedAtStart());
+#endif
+  MOZ_ASSERT(!lir->isCall());
+
+  uint32_t vreg = getVirtualRegister();
+
+  LDefinition def1(LDefinition::GENERAL, LDefinition::MUST_REUSE_INPUT);
+  def1.setReusedInput(operand);
+  lir->setDef(0, def1);
+  lir->getDef(0)->setVirtualRegister(vreg);
+
+#if JS_BITS_PER_WORD == 32
+  getVirtualRegister();
+  LDefinition def2(LDefinition::GENERAL, LDefinition::MUST_REUSE_INPUT);
+  def2.setReusedInput(operand + 1);
+  lir->setDef(1, def2);
+  lir->getDef(1)->setVirtualRegister(vreg + 1);
+#endif
+
+  lir->setMir(mir);
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+template <size_t Ops, size_t Temps>
+void LIRGeneratorShared::defineBoxReuseInput(
+    LInstructionHelper<BOX_PIECES, Ops, Temps>* lir, MDefinition* mir,
+    uint32_t operand) {
+  // The input should be used at the start of the instruction, to avoid moves.
+  MOZ_ASSERT(lir->getOperand(operand)->toUse()->usedAtStart());
+#ifdef JS_NUNBOX32
+  MOZ_ASSERT(lir->getOperand(operand + 1)->toUse()->usedAtStart());
+#endif
+  MOZ_ASSERT(!lir->isCall());
+  MOZ_ASSERT(mir->type() == MIRType::Value);
+
+  uint32_t vreg = getVirtualRegister();
+
+#ifdef JS_NUNBOX32
+  static_assert(VREG_TYPE_OFFSET == 0,
+                "Code below assumes VREG_TYPE_OFFSET == 0");
+  static_assert(VREG_DATA_OFFSET == 1,
+                "Code below assumes VREG_DATA_OFFSET == 1");
+
+  LDefinition def1(LDefinition::TYPE, LDefinition::MUST_REUSE_INPUT);
+  def1.setReusedInput(operand);
+  def1.setVirtualRegister(vreg);
+  lir->setDef(0, def1);
+
+  getVirtualRegister();
+  LDefinition def2(LDefinition::PAYLOAD, LDefinition::MUST_REUSE_INPUT);
+  def2.setReusedInput(operand + 1);
+  def2.setVirtualRegister(vreg + 1);
+  lir->setDef(1, def2);
+#else
+  LDefinition def(LDefinition::BOX, LDefinition::MUST_REUSE_INPUT);
+  def.setReusedInput(operand);
+  def.setVirtualRegister(vreg);
+  lir->setDef(0, def);
+#endif
+
+  lir->setMir(mir);
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+template <size_t Temps>
+void LIRGeneratorShared::defineBox(
+    details::LInstructionFixedDefsTempsHelper<BOX_PIECES, Temps>* lir,
+    MDefinition* mir, LDefinition::Policy policy) {
+  // Call instructions should use defineReturn.
+  MOZ_ASSERT(!lir->isCall());
+  MOZ_ASSERT(mir->type() == MIRType::Value);
+
+  uint32_t vreg = getVirtualRegister();
+
+#if defined(JS_NUNBOX32)
+  lir->setDef(0,
+              LDefinition(vreg + VREG_TYPE_OFFSET, LDefinition::TYPE, policy));
+  lir->setDef(
+      1, LDefinition(vreg + VREG_DATA_OFFSET, LDefinition::PAYLOAD, policy));
+  getVirtualRegister();
+#elif defined(JS_PUNBOX64)
+  lir->setDef(0, LDefinition(vreg, LDefinition::BOX, policy));
+#endif
+  lir->setMir(mir);
+
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+template <size_t Ops, size_t Temps>
+void LIRGeneratorShared::defineInt64(
+    LInstructionHelper<INT64_PIECES, Ops, Temps>* lir, MDefinition* mir,
+    LDefinition::Policy policy) {
+  // Call instructions should use defineReturn.
+  MOZ_ASSERT(!lir->isCall());
+
+#ifdef JS_64BIT
+  MOZ_ASSERT(mir->type() == MIRType::Int64 || mir->type() == MIRType::IntPtr);
+#else
+  MOZ_ASSERT(mir->type() == MIRType::Int64);
+#endif
+
+  uint32_t vreg = getVirtualRegister();
+
+#if JS_BITS_PER_WORD == 32
+  lir->setDef(0,
+              LDefinition(vreg + INT64LOW_INDEX, LDefinition::GENERAL, policy));
+  lir->setDef(
+      1, LDefinition(vreg + INT64HIGH_INDEX, LDefinition::GENERAL, policy));
+  getVirtualRegister();
+#else
+  lir->setDef(0, LDefinition(vreg, LDefinition::GENERAL, policy));
+#endif
+  lir->setMir(mir);
+
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+void LIRGeneratorShared::defineReturn(LInstruction* lir, MDefinition* mir) {
+  lir->setMir(mir);
+
+  MOZ_ASSERT(lir->isCall());
+
+  uint32_t vreg = getVirtualRegister();
+
+  switch (mir->type()) {
+    case MIRType::Value:
+#if defined(JS_NUNBOX32)
+      lir->setDef(TYPE_INDEX,
+                  LDefinition(vreg + VREG_TYPE_OFFSET, LDefinition::TYPE,
+                              LGeneralReg(JSReturnReg_Type)));
+      lir->setDef(PAYLOAD_INDEX,
+                  LDefinition(vreg + VREG_DATA_OFFSET, LDefinition::PAYLOAD,
+                              LGeneralReg(JSReturnReg_Data)));
+      getVirtualRegister();
+#elif defined(JS_PUNBOX64)
+      lir->setDef(
+          0, LDefinition(vreg, LDefinition::BOX, LGeneralReg(JSReturnReg)));
+#endif
+      break;
+    case MIRType::Int64:
+#if defined(JS_NUNBOX32)
+      lir->setDef(INT64LOW_INDEX,
+                  LDefinition(vreg + INT64LOW_INDEX, LDefinition::GENERAL,
+                              LGeneralReg(ReturnReg64.low)));
+      lir->setDef(INT64HIGH_INDEX,
+                  LDefinition(vreg + INT64HIGH_INDEX, LDefinition::GENERAL,
+                              LGeneralReg(ReturnReg64.high)));
+      getVirtualRegister();
+#elif defined(JS_PUNBOX64)
+      lir->setDef(
+          0, LDefinition(vreg, LDefinition::GENERAL, LGeneralReg(ReturnReg)));
+#endif
+      break;
+    case MIRType::Float32:
+      lir->setDef(0, LDefinition(vreg, LDefinition::FLOAT32,
+                                 LFloatReg(ReturnFloat32Reg)));
+      break;
+    case MIRType::Double:
+      lir->setDef(0, LDefinition(vreg, LDefinition::DOUBLE,
+                                 LFloatReg(ReturnDoubleReg)));
+      break;
+    case MIRType::Simd128:
+#ifdef ENABLE_WASM_SIMD
+      lir->setDef(0, LDefinition(vreg, LDefinition::SIMD128,
+                                 LFloatReg(ReturnSimd128Reg)));
+      break;
+#else
+      MOZ_CRASH("No SIMD support");
+#endif
+    default:
+      LDefinition::Type type = LDefinition::TypeFrom(mir->type());
+      switch (type) {
+        case LDefinition::GENERAL:
+        case LDefinition::INT32:
+        case LDefinition::OBJECT:
+        case LDefinition::SLOTS:
+        case LDefinition::STACKRESULTS:
+          lir->setDef(0, LDefinition(vreg, type, LGeneralReg(ReturnReg)));
+          break;
+        case LDefinition::DOUBLE:
+        case LDefinition::FLOAT32:
+        case LDefinition::SIMD128:
+          MOZ_CRASH("Float cases must have been handled earlier");
+        default:
+          MOZ_CRASH("Unexpected type");
+      }
+      break;
+  }
+
+  mir->setVirtualRegister(vreg);
+  add(lir);
+}
+
+#ifdef DEBUG
+// This function checks that when making redefinitions, we don't accidentally
+// coerce two incompatible types.
+static inline bool IsCompatibleLIRCoercion(MIRType to, MIRType from) {
+  if (to == from) {
+    return true;
+  }
+  // In LIR, we treat boolean and int32 as the same low-level type (INTEGER).
+  // When snapshotting, we recover the actual JS type from MIR.
+  if ((to == MIRType::Int32 || to == MIRType::Boolean) &&
+      (from == MIRType::Int32 || from == MIRType::Boolean)) {
+    return true;
+  }
+  // On 32-bit platforms Int32 can be redefined as IntPtr and vice versa.
+  // On 64-bit platforms we can redefine non-negative Int32 values as IntPtr.
+  if (from == MIRType::Int32 && to == MIRType::IntPtr) {
+    return true;
+  }
+#  ifndef JS_64BIT
+  if (from == MIRType::IntPtr && to == MIRType::Int32) {
+    return true;
+  }
+#  endif
+  return false;
+}
+#endif
+
+void LIRGeneratorShared::redefine(MDefinition* def, MDefinition* as) {
+  MOZ_ASSERT(IsCompatibleLIRCoercion(def->type(), as->type()));
+
+  // Try to emit MIR marked as emitted-at-uses at, well, uses. For
+  // snapshotting reasons we delay the MIRTypes match, or when we are
+  // coercing between bool and int32 constants.
+  if (as->isEmittedAtUses() &&
+      (def->type() == as->type() ||
+       (as->isConstant() &&
+        (def->type() == MIRType::Int32 || def->type() == MIRType::Boolean) &&
+        (as->type() == MIRType::Int32 || as->type() == MIRType::Boolean)))) {
+    MInstruction* replacement;
+    if (def->type() != as->type()) {
+      if (as->type() == MIRType::Int32) {
+        replacement =
+            MConstant::New(alloc(), BooleanValue(as->toConstant()->toInt32()));
+      } else {
+        replacement =
+            MConstant::New(alloc(), Int32Value(as->toConstant()->toBoolean()));
+      }
+      def->block()->insertBefore(def->toInstruction(), replacement);
+      emitAtUses(replacement->toInstruction());
+    } else {
+      replacement = as->toInstruction();
+    }
+    def->replaceAllUsesWith(replacement);
+  } else {
+    ensureDefined(as);
+    def->setVirtualRegister(as->virtualRegister());
+  }
+}
+
+void LIRGeneratorShared::ensureDefined(MDefinition* mir) {
+  if (mir->isEmittedAtUses()) {
+    visitEmittedAtUses(mir->toInstruction());
+    MOZ_ASSERT(mir->isLowered());
+  }
+}
+
+bool LIRGeneratorShared::willHaveDifferentLIRNodes(MDefinition* mir1,
+                                                   MDefinition* mir2) {
+  if (mir1 != mir2) {
+    return true;
+  }
+  if (mir1->isEmittedAtUses()) {
+    return true;
+  }
+  return false;
+}
+
+template <typename LClass, typename... Args>
+LClass* LIRGeneratorShared::allocateVariadic(uint32_t numOperands,
+                                             Args&&... args) {
+  size_t numBytes = sizeof(LClass) + numOperands * sizeof(LAllocation);
+  void* buf = alloc().allocate(numBytes);
+  if (!buf) {
+    return nullptr;
+  }
+
+  LClass* ins = static_cast<LClass*>(buf);
+  new (ins) LClass(numOperands, std::forward<Args>(args)...);
+
+  ins->initOperandsOffset(sizeof(LClass));
+
+  for (uint32_t i = 0; i < numOperands; i++) {
+    ins->setOperand(i, LAllocation());
+  }
+
+  return ins;
+}
+
+LUse LIRGeneratorShared::useRegister(MDefinition* mir) {
+  return use(mir, LUse(LUse::REGISTER));
+}
+
+LUse LIRGeneratorShared::useRegisterAtStart(MDefinition* mir) {
+  return use(mir, LUse(LUse::REGISTER, true));
+}
+
+LUse LIRGeneratorShared::use(MDefinition* mir) {
+  return use(mir, LUse(LUse::ANY));
+}
+
+LUse LIRGeneratorShared::useAtStart(MDefinition* mir) {
+  return use(mir, LUse(LUse::ANY, true));
+}
+
+LAllocation LIRGeneratorShared::useOrConstant(MDefinition* mir) {
+  if (mir->isConstant()) {
+    return LAllocation(mir->toConstant());
+  }
+  return use(mir);
+}
+
+LAllocation LIRGeneratorShared::useOrConstantAtStart(MDefinition* mir) {
+  if (mir->isConstant()) {
+    return LAllocation(mir->toConstant());
+  }
+  return useAtStart(mir);
+}
+
+LAllocation LIRGeneratorShared::useRegisterOrConstant(MDefinition* mir) {
+  if (mir->isConstant()) {
+    return LAllocation(mir->toConstant());
+  }
+  return useRegister(mir);
+}
+
+LAllocation LIRGeneratorShared::useRegisterOrConstantAtStart(MDefinition* mir) {
+  if (mir->isConstant()) {
+    return LAllocation(mir->toConstant());
+  }
+  return useRegisterAtStart(mir);
+}
+
+inline bool CanUseInt32Constant(MDefinition* mir) {
+  if (!mir->isConstant()) {
+    return false;
+  }
+  MConstant* cst = mir->toConstant();
+  if (cst->type() == MIRType::IntPtr) {
+    return INT32_MIN <= cst->toIntPtr() && cst->toIntPtr() <= INT32_MAX;
+  }
+  MOZ_ASSERT(cst->type() == MIRType::Int32);
+  return true;
+}
+
+LAllocation LIRGeneratorShared::useRegisterOrInt32Constant(MDefinition* mir) {
+  if (CanUseInt32Constant(mir)) {
+    return LAllocation(mir->toConstant());
+  }
+  return useRegister(mir);
+}
+
+LAllocation LIRGeneratorShared::useAnyOrInt32Constant(MDefinition* mir) {
+  if (CanUseInt32Constant(mir)) {
+    return LAllocation(mir->toConstant());
+  }
+  return useAny(mir);
+}
+
+LAllocation LIRGeneratorShared::useRegisterOrZero(MDefinition* mir) {
+  if (mir->isConstant() &&
+      (mir->toConstant()->isInt32(0) || mir->toConstant()->isInt64(0))) {
+    return LAllocation();
+  }
+  return useRegister(mir);
+}
+
+LAllocation LIRGeneratorShared::useRegisterOrZeroAtStart(MDefinition* mir) {
+  if (mir->isConstant() &&
+      (mir->toConstant()->isInt32(0) || mir->toConstant()->isInt64(0))) {
+    return LAllocation();
+  }
+  return useRegisterAtStart(mir);
+}
+
+LAllocation LIRGeneratorShared::useRegisterOrNonDoubleConstant(
+    MDefinition* mir) {
+  if (mir->isConstant() && mir->type() != MIRType::Double &&
+      mir->type() != MIRType::Float32) {
+    return LAllocation(mir->toConstant());
+  }
+  return useRegister(mir);
+}
+
+#if defined(JS_CODEGEN_ARM) || defined(JS_CODEGEN_ARM64) ||      \
+    defined(JS_CODEGEN_LOONG64) || defined(JS_CODEGEN_MIPS64) || \
+    defined(JS_CODEGEN_RISCV64)
+LAllocation LIRGeneratorShared::useAnyOrConstant(MDefinition* mir) {
+  return useRegisterOrConstant(mir);
+}
+LAllocation LIRGeneratorShared::useStorable(MDefinition* mir) {
+  return useRegister(mir);
+}
+LAllocation LIRGeneratorShared::useStorableAtStart(MDefinition* mir) {
+  return useRegisterAtStart(mir);
+}
+
+LAllocation LIRGeneratorShared::useAny(MDefinition* mir) {
+  return useRegister(mir);
+}
+LAllocation LIRGeneratorShared::useAnyAtStart(MDefinition* mir) {
+  return useRegisterAtStart(mir);
+}
+#else
+LAllocation LIRGeneratorShared::useAnyOrConstant(MDefinition* mir) {
+  return useOrConstant(mir);
+}
+
+LAllocation LIRGeneratorShared::useAny(MDefinition* mir) { return use(mir); }
+LAllocation LIRGeneratorShared::useAnyAtStart(MDefinition* mir) {
+  return useAtStart(mir);
+}
+LAllocation LIRGeneratorShared::useStorable(MDefinition* mir) {
+  return useRegisterOrConstant(mir);
+}
+LAllocation LIRGeneratorShared::useStorableAtStart(MDefinition* mir) {
+  return useRegisterOrConstantAtStart(mir);
+}
+
+#endif
+
+LAllocation LIRGeneratorShared::useKeepalive(MDefinition* mir) {
+  return use(mir, LUse(LUse::KEEPALIVE));
+}
+
+LAllocation LIRGeneratorShared::useKeepaliveOrConstant(MDefinition* mir) {
+  if (mir->isConstant()) {
+    return LAllocation(mir->toConstant());
+  }
+  return useKeepalive(mir);
+}
+
+LUse LIRGeneratorShared::useFixed(MDefinition* mir, Register reg) {
+  return use(mir, LUse(reg));
+}
+
+LUse LIRGeneratorShared::useFixedAtStart(MDefinition* mir, Register reg) {
+  return use(mir, LUse(reg, true));
+}
+
+LUse LIRGeneratorShared::useFixed(MDefinition* mir, FloatRegister reg) {
+  return use(mir, LUse(reg));
+}
+
+LUse LIRGeneratorShared::useFixed(MDefinition* mir, AnyRegister reg) {
+  return reg.isFloat() ? use(mir, LUse(reg.fpu())) : use(mir, LUse(reg.gpr()));
+}
+
+LUse LIRGeneratorShared::useFixedAtStart(MDefinition* mir, AnyRegister reg) {
+  return reg.isFloat() ? use(mir, LUse(reg.fpu(), true))
+                       : use(mir, LUse(reg.gpr(), true));
+}
+
+LDefinition LIRGeneratorShared::temp(LDefinition::Type type,
+                                     LDefinition::Policy policy) {
+  return LDefinition(getVirtualRegister(), type, policy);
+}
+
+LInt64Definition LIRGeneratorShared::tempInt64(LDefinition::Policy policy) {
+#if JS_BITS_PER_WORD == 32
+  LDefinition high = temp(LDefinition::GENERAL, policy);
+  LDefinition low = temp(LDefinition::GENERAL, policy);
+  return LInt64Definition(high, low);
+#else
+  return LInt64Definition(temp(LDefinition::GENERAL, policy));
+#endif
+}
+
+LDefinition LIRGeneratorShared::tempFixed(Register reg) {
+  LDefinition t = temp(LDefinition::GENERAL);
+  t.setOutput(LGeneralReg(reg));
+  return t;
+}
+
+LInt64Definition LIRGeneratorShared::tempInt64Fixed(Register64 reg) {
+#if JS_BITS_PER_WORD == 32
+  LDefinition high = temp(LDefinition::GENERAL);
+  LDefinition low = temp(LDefinition::GENERAL);
+  high.setOutput(LGeneralReg(reg.high));
+  low.setOutput(LGeneralReg(reg.low));
+  return LInt64Definition(high, low);
+#else
+  LDefinition t = temp(LDefinition::GENERAL);
+  t.setOutput(LGeneralReg(reg.reg));
+  return LInt64Definition(t);
+#endif
+}
+
+LDefinition LIRGeneratorShared::tempFixed(FloatRegister reg) {
+  LDefinition t = temp(LDefinition::DOUBLE);
+  t.setOutput(LFloatReg(reg));
+  return t;
+}
+
+LDefinition LIRGeneratorShared::tempFloat32() {
+  return temp(LDefinition::FLOAT32);
+}
+
+LDefinition LIRGeneratorShared::tempDouble() {
+  return temp(LDefinition::DOUBLE);
+}
+
+#ifdef ENABLE_WASM_SIMD
+LDefinition LIRGeneratorShared::tempSimd128() {
+  return temp(LDefinition::SIMD128);
+}
+#endif
+
+LDefinition LIRGeneratorShared::tempCopy(MDefinition* input,
+                                         uint32_t reusedInput) {
+  MOZ_ASSERT(input->virtualRegister());
+  LDefinition t =
+      temp(LDefinition::TypeFrom(input->type()), LDefinition::MUST_REUSE_INPUT);
+  t.setReusedInput(reusedInput);
+  return t;
+}
+
+template <typename T>
+void LIRGeneratorShared::annotate(T* ins) {
+  ins->setId(lirGraph_.getInstructionId());
+}
+
+template <typename T>
+void LIRGeneratorShared::add(T* ins, MInstruction* mir) {
+  MOZ_ASSERT(!ins->isPhi());
+  current->add(ins);
+  if (mir) {
+    MOZ_ASSERT(current == mir->block()->lir());
+    ins->setMir(mir);
+  }
+  annotate(ins);
+  if (ins->isCall()) {
+    gen->setNeedsOverrecursedCheck();
+    gen->setNeedsStaticStackAlignment();
+  }
+}
+
+#ifdef JS_NUNBOX32
+// Returns the virtual register of a js::Value-defining instruction. This is
+// abstracted because MBox is a special value-returning instruction that
+// redefines its input payload if its input is not constant. Therefore, it is
+// illegal to request a box's payload by adding VREG_DATA_OFFSET to its raw id.
+static inline uint32_t VirtualRegisterOfPayload(MDefinition* mir) {
+  if (mir->isBox()) {
+    MDefinition* inner = mir->toBox()->getOperand(0);
+    if (!inner->isConstant() && inner->type() != MIRType::Double &&
+        inner->type() != MIRType::Float32) {
+      return inner->virtualRegister();
+    }
+  }
+  return mir->virtualRegister() + VREG_DATA_OFFSET;
+}
+
+// Note: always call ensureDefined before calling useType/usePayload,
+// so that emitted-at-use operands are handled correctly.
+LUse LIRGeneratorShared::useType(MDefinition* mir, LUse::Policy policy) {
+  MOZ_ASSERT(mir->type() == MIRType::Value);
+
+  return LUse(mir->virtualRegister() + VREG_TYPE_OFFSET, policy);
+}
+
+LUse LIRGeneratorShared::usePayload(MDefinition* mir, LUse::Policy policy) {
+  MOZ_ASSERT(mir->type() == MIRType::Value);
+
+  return LUse(VirtualRegisterOfPayload(mir), policy);
+}
+
+LUse LIRGeneratorShared::usePayloadAtStart(MDefinition* mir,
+                                           LUse::Policy policy) {
+  MOZ_ASSERT(mir->type() == MIRType::Value);
+
+  return LUse(VirtualRegisterOfPayload(mir), policy, true);
+}
+
+LUse LIRGeneratorShared::usePayloadInRegisterAtStart(MDefinition* mir) {
+  return usePayloadAtStart(mir, LUse::REGISTER);
+}
+
+void LIRGeneratorShared::fillBoxUses(LInstruction* lir, size_t n,
+                                     MDefinition* mir) {
+  ensureDefined(mir);
+  lir->getOperand(n)->toUse()->setVirtualRegister(mir->virtualRegister() +
+                                                  VREG_TYPE_OFFSET);
+  lir->getOperand(n + 1)->toUse()->setVirtualRegister(
+      VirtualRegisterOfPayload(mir));
+}
+#endif
+
+LUse LIRGeneratorShared::useRegisterForTypedLoad(MDefinition* mir,
+                                                 MIRType type) {
+  MOZ_ASSERT(type != MIRType::Value && type != MIRType::None);
+  MOZ_ASSERT(mir->type() == MIRType::Object || mir->type() == MIRType::Slots);
+
+#ifdef JS_PUNBOX64
+  // On x64, masm.loadUnboxedValue emits slightly less efficient code when
+  // the input and output use the same register and we're not loading an
+  // int32/bool/double, so we just call useRegister in this case.
+  if (type != MIRType::Int32 && type != MIRType::Boolean &&
+      type != MIRType::Double) {
+    return useRegister(mir);
+  }
+#endif
+
+  return useRegisterAtStart(mir);
+}
+
+LBoxAllocation LIRGeneratorShared::useBox(MDefinition* mir, LUse::Policy policy,
+                                          bool useAtStart) {
+  MOZ_ASSERT(mir->type() == MIRType::Value);
+
+  ensureDefined(mir);
+
+#if defined(JS_NUNBOX32)
+  return LBoxAllocation(
+      LUse(mir->virtualRegister(), policy, useAtStart),
+      LUse(VirtualRegisterOfPayload(mir), policy, useAtStart));
+#else
+  return LBoxAllocation(LUse(mir->virtualRegister(), policy, useAtStart));
+#endif
+}
+
+LBoxAllocation LIRGeneratorShared::useBoxOrTyped(MDefinition* mir,
+                                                 bool useAtStart) {
+  if (mir->type() == MIRType::Value) {
+    return useBox(mir, LUse::REGISTER, useAtStart);
+  }
+
+#if defined(JS_NUNBOX32)
+  return LBoxAllocation(useAtStart ? useRegisterAtStart(mir) : useRegister(mir),
+                        LAllocation());
+#else
+  return LBoxAllocation(useAtStart ? useRegisterAtStart(mir)
+                                   : useRegister(mir));
+#endif
+}
+
+LBoxAllocation LIRGeneratorShared::useBoxOrTypedOrConstant(MDefinition* mir,
+                                                           bool useConstant,
+                                                           bool useAtStart) {
+  if (useConstant && mir->isConstant()) {
+#if defined(JS_NUNBOX32)
+    return LBoxAllocation(LAllocation(mir->toConstant()), LAllocation());
+#else
+    return LBoxAllocation(LAllocation(mir->toConstant()));
+#endif
+  }
+
+  return useBoxOrTyped(mir, useAtStart);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64(MDefinition* mir,
+                                              LUse::Policy policy,
+                                              bool useAtStart) {
+  MOZ_ASSERT(mir->type() == MIRType::Int64);
+
+  ensureDefined(mir);
+
+  uint32_t vreg = mir->virtualRegister();
+#if JS_BITS_PER_WORD == 32
+  return LInt64Allocation(LUse(vreg + INT64HIGH_INDEX, policy, useAtStart),
+                          LUse(vreg + INT64LOW_INDEX, policy, useAtStart));
+#else
+  return LInt64Allocation(LUse(vreg, policy, useAtStart));
+#endif
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64Fixed(MDefinition* mir,
+                                                   Register64 regs,
+                                                   bool useAtStart) {
+  MOZ_ASSERT(mir->type() == MIRType::Int64);
+
+  ensureDefined(mir);
+
+  uint32_t vreg = mir->virtualRegister();
+#if JS_BITS_PER_WORD == 32
+  return LInt64Allocation(LUse(regs.high, vreg + INT64HIGH_INDEX, useAtStart),
+                          LUse(regs.low, vreg + INT64LOW_INDEX, useAtStart));
+#else
+  return LInt64Allocation(LUse(regs.reg, vreg, useAtStart));
+#endif
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64FixedAtStart(MDefinition* mir,
+                                                          Register64 regs) {
+  return useInt64Fixed(mir, regs, true);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64(MDefinition* mir,
+                                              bool useAtStart) {
+  // On 32-bit platforms, always load the value in registers.
+#if JS_BITS_PER_WORD == 32
+  return useInt64(mir, LUse::REGISTER, useAtStart);
+#else
+  return useInt64(mir, LUse::ANY, useAtStart);
+#endif
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64AtStart(MDefinition* mir) {
+  return useInt64(mir, /* useAtStart = */ true);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64Register(MDefinition* mir,
+                                                      bool useAtStart) {
+  return useInt64(mir, LUse::REGISTER, useAtStart);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64OrConstant(MDefinition* mir,
+                                                        bool useAtStart) {
+  if (mir->isConstant()) {
+#if defined(JS_NUNBOX32)
+    return LInt64Allocation(LAllocation(mir->toConstant()), LAllocation());
+#else
+    return LInt64Allocation(LAllocation(mir->toConstant()));
+#endif
+  }
+  return useInt64(mir, useAtStart);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64RegisterOrConstant(
+    MDefinition* mir, bool useAtStart) {
+  if (mir->isConstant()) {
+#if defined(JS_NUNBOX32)
+    return LInt64Allocation(LAllocation(mir->toConstant()), LAllocation());
+#else
+    return LInt64Allocation(LAllocation(mir->toConstant()));
+#endif
+  }
+  return useInt64Register(mir, useAtStart);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64RegisterAtStart(MDefinition* mir) {
+  return useInt64Register(mir, /* useAtStart = */ true);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64RegisterOrConstantAtStart(
+    MDefinition* mir) {
+  return useInt64RegisterOrConstant(mir, /* useAtStart = */ true);
+}
+
+LInt64Allocation LIRGeneratorShared::useInt64OrConstantAtStart(
+    MDefinition* mir) {
+  return useInt64OrConstant(mir, /* useAtStart = */ true);
+}
+
+void LIRGeneratorShared::lowerConstantDouble(double d, MInstruction* mir) {
+  define(new (alloc()) LDouble(d), mir);
+}
+void LIRGeneratorShared::lowerConstantFloat32(float f, MInstruction* mir) {
+  define(new (alloc()) LFloat32(f), mir);
+}
+
+}  // namespace jit
+}  // namespace js
+
+#endif /* jit_shared_Lowering_shared_inl_h */