1 files changed, 718 insertions, 0 deletions
diff --git a/js/src/jit/LIR.cpp b/js/src/jit/LIR.cpp
new file mode 100644
index 0000000000..a9fd9d3162
--- /dev/null
+++ b/js/src/jit/LIR.cpp
@@ -0,0 +1,718 @@
+/* -*- 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/LIR.h"
+
+#include "mozilla/ScopeExit.h"
+
+#include <type_traits>
+
+#include "jit/JitSpewer.h"
+#include "jit/MIR.h"
+#include "jit/MIRGenerator.h"
+#include "js/Printf.h"
+#include "util/Unicode.h"
+
+using namespace js;
+using namespace js::jit;
+
+LIRGraph::LIRGraph(MIRGraph* mir)
+    : blocks_(),
+      constantPool_(mir->alloc()),
+      constantPoolMap_(mir->alloc()),
+      safepoints_(mir->alloc()),
+      nonCallSafepoints_(mir->alloc()),
+      numVirtualRegisters_(0),
+      numInstructions_(1),  // First id is 1.
+      localSlotCount_(0),
+      argumentSlotCount_(0),
+      mir_(*mir) {}
+
+bool LIRGraph::addConstantToPool(const Value& v, uint32_t* index) {
+  ConstantPoolMap::AddPtr p = constantPoolMap_.lookupForAdd(v);
+  if (p) {
+    *index = p->value();
+    return true;
+  }
+  *index = constantPool_.length();
+  return constantPool_.append(v) && constantPoolMap_.add(p, v, *index);
+}
+
+bool LIRGraph::noteNeedsSafepoint(LInstruction* ins) {
+  // Instructions with safepoints must be in linear order.
+  MOZ_ASSERT_IF(!safepoints_.empty(), safepoints_.back()->id() < ins->id());
+  if (!ins->isCall() && !nonCallSafepoints_.append(ins)) {
+    return false;
+  }
+  return safepoints_.append(ins);
+}
+
+#ifdef JS_JITSPEW
+void LIRGraph::dump(GenericPrinter& out) {
+  for (size_t i = 0; i < numBlocks(); i++) {
+    getBlock(i)->dump(out);
+    out.printf("\n");
+  }
+}
+
+void LIRGraph::dump() {
+  Fprinter out(stderr);
+  dump(out);
+  out.finish();
+}
+#endif
+
+LBlock::LBlock(MBasicBlock* from)
+    : block_(from), phis_(), entryMoveGroup_(nullptr), exitMoveGroup_(nullptr) {
+  from->assignLir(this);
+}
+
+bool LBlock::init(TempAllocator& alloc) {
+  // Count the number of LPhis we'll need.
+  size_t numLPhis = 0;
+  for (MPhiIterator i(block_->phisBegin()), e(block_->phisEnd()); i != e; ++i) {
+    MPhi* phi = *i;
+    switch (phi->type()) {
+      case MIRType::Value:
+        numLPhis += BOX_PIECES;
+        break;
+      case MIRType::Int64:
+        numLPhis += INT64_PIECES;
+        break;
+      default:
+        numLPhis += 1;
+        break;
+    }
+  }
+
+  // Allocate space for the LPhis.
+  if (!phis_.init(alloc, numLPhis)) {
+    return false;
+  }
+
+  // For each MIR phi, set up LIR phis as appropriate. We'll fill in their
+  // operands on each incoming edge, and set their definitions at the start of
+  // their defining block.
+  size_t phiIndex = 0;
+  size_t numPreds = block_->numPredecessors();
+  for (MPhiIterator i(block_->phisBegin()), e(block_->phisEnd()); i != e; ++i) {
+    MPhi* phi = *i;
+    MOZ_ASSERT(phi->numOperands() == numPreds);
+
+    int numPhis;
+    switch (phi->type()) {
+      case MIRType::Value:
+        numPhis = BOX_PIECES;
+        break;
+      case MIRType::Int64:
+        numPhis = INT64_PIECES;
+        break;
+      default:
+        numPhis = 1;
+        break;
+    }
+    for (int i = 0; i < numPhis; i++) {
+      LAllocation* inputs = alloc.allocateArray<LAllocation>(numPreds);
+      if (!inputs) {
+        return false;
+      }
+
+      void* addr = &phis_[phiIndex++];
+      LPhi* lphi = new (addr) LPhi(phi, inputs);
+      lphi->setBlock(this);
+    }
+  }
+  return true;
+}
+
+const LInstruction* LBlock::firstInstructionWithId() const {
+  for (LInstructionIterator i(instructions_.begin()); i != instructions_.end();
+       ++i) {
+    if (i->id()) {
+      return *i;
+    }
+  }
+  return 0;
+}
+
+LMoveGroup* LBlock::getEntryMoveGroup(TempAllocator& alloc) {
+  if (entryMoveGroup_) {
+    return entryMoveGroup_;
+  }
+  entryMoveGroup_ = LMoveGroup::New(alloc);
+  insertBefore(*begin(), entryMoveGroup_);
+  return entryMoveGroup_;
+}
+
+LMoveGroup* LBlock::getExitMoveGroup(TempAllocator& alloc) {
+  if (exitMoveGroup_) {
+    return exitMoveGroup_;
+  }
+  exitMoveGroup_ = LMoveGroup::New(alloc);
+  insertBefore(*rbegin(), exitMoveGroup_);
+  return exitMoveGroup_;
+}
+
+#ifdef JS_JITSPEW
+void LBlock::dump(GenericPrinter& out) {
+  out.printf("block%u:\n", mir()->id());
+  for (size_t i = 0; i < numPhis(); ++i) {
+    getPhi(i)->dump(out);
+    out.printf("\n");
+  }
+  for (LInstructionIterator iter = begin(); iter != end(); iter++) {
+    iter->dump(out);
+    if (iter->safepoint()) {
+      out.printf(" SAFEPOINT(0x%p) ", iter->safepoint());
+    }
+    out.printf("\n");
+  }
+}
+
+void LBlock::dump() {
+  Fprinter out(stderr);
+  dump(out);
+  out.finish();
+}
+#endif
+
+static size_t TotalOperandCount(LRecoverInfo* recoverInfo) {
+  size_t accum = 0;
+  for (LRecoverInfo::OperandIter it(recoverInfo); !it; ++it) {
+    if (!it->isRecoveredOnBailout()) {
+      accum++;
+    }
+  }
+  return accum;
+}
+
+LRecoverInfo::LRecoverInfo(TempAllocator& alloc)
+    : instructions_(alloc), recoverOffset_(INVALID_RECOVER_OFFSET) {}
+
+LRecoverInfo* LRecoverInfo::New(MIRGenerator* gen, MResumePoint* mir) {
+  LRecoverInfo* recoverInfo = new (gen->alloc()) LRecoverInfo(gen->alloc());
+  if (!recoverInfo || !recoverInfo->init(mir)) {
+    return nullptr;
+  }
+
+  JitSpew(JitSpew_IonSnapshots, "Generating LIR recover info %p from MIR (%p)",
+          (void*)recoverInfo, (void*)mir);
+
+  return recoverInfo;
+}
+
+// de-virtualise MResumePoint::getOperand calls.
+template <typename Node>
+bool LRecoverInfo::appendOperands(Node* ins) {
+  for (size_t i = 0, end = ins->numOperands(); i < end; i++) {
+    MDefinition* def = ins->getOperand(i);
+
+    // As there is no cycle in the data-flow (without MPhi), checking for
+    // isInWorkList implies that the definition is already in the
+    // instruction vector, and not processed by a caller of the current
+    // function.
+    if (def->isRecoveredOnBailout() && !def->isInWorklist()) {
+      if (!appendDefinition(def)) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+bool LRecoverInfo::appendDefinition(MDefinition* def) {
+  MOZ_ASSERT(def->isRecoveredOnBailout());
+  def->setInWorklist();
+  auto clearWorklistFlagOnFailure =
+      mozilla::MakeScopeExit([&] { def->setNotInWorklist(); });
+
+  if (!appendOperands(def)) {
+    return false;
+  }
+
+  if (!instructions_.append(def)) {
+    return false;
+  }
+
+  clearWorklistFlagOnFailure.release();
+  return true;
+}
+
+bool LRecoverInfo::appendResumePoint(MResumePoint* rp) {
+  // Stores should be recovered first.
+  for (auto iter(rp->storesBegin()), end(rp->storesEnd()); iter != end;
+       ++iter) {
+    if (!appendDefinition(iter->operand)) {
+      return false;
+    }
+  }
+
+  if (rp->caller() && !appendResumePoint(rp->caller())) {
+    return false;
+  }
+
+  if (!appendOperands(rp)) {
+    return false;
+  }
+
+  return instructions_.append(rp);
+}
+
+bool LRecoverInfo::init(MResumePoint* rp) {
+  // Before exiting this function, remove temporary flags from all definitions
+  // added in the vector.
+  auto clearWorklistFlags = mozilla::MakeScopeExit([&] {
+    for (MNode** it = begin(); it != end(); it++) {
+      if (!(*it)->isDefinition()) {
+        continue;
+      }
+      (*it)->toDefinition()->setNotInWorklist();
+    }
+  });
+
+  // Sort operations in the order in which we need to restore the stack. This
+  // implies that outer frames, as well as operations needed to recover the
+  // current frame, are located before the current frame. The inner-most
+  // resume point should be the last element in the list.
+  if (!appendResumePoint(rp)) {
+    return false;
+  }
+
+  MOZ_ASSERT(mir() == rp);
+  return true;
+}
+
+LSnapshot::LSnapshot(LRecoverInfo* recoverInfo, BailoutKind kind)
+    : slots_(nullptr),
+      recoverInfo_(recoverInfo),
+      snapshotOffset_(INVALID_SNAPSHOT_OFFSET),
+      numSlots_(TotalOperandCount(recoverInfo) * BOX_PIECES),
+      bailoutId_(INVALID_BAILOUT_ID),
+      bailoutKind_(kind) {}
+
+bool LSnapshot::init(MIRGenerator* gen) {
+  slots_ = gen->allocate<LAllocation>(numSlots_);
+  return !!slots_;
+}
+
+LSnapshot* LSnapshot::New(MIRGenerator* gen, LRecoverInfo* recover,
+                          BailoutKind kind) {
+  LSnapshot* snapshot = new (gen->alloc()) LSnapshot(recover, kind);
+  if (!snapshot || !snapshot->init(gen)) {
+    return nullptr;
+  }
+
+  JitSpew(JitSpew_IonSnapshots, "Generating LIR snapshot %p from recover (%p)",
+          (void*)snapshot, (void*)recover);
+
+  return snapshot;
+}
+
+void LSnapshot::rewriteRecoveredInput(LUse input) {
+  // Mark any operands to this snapshot with the same value as input as being
+  // equal to the instruction's result.
+  for (size_t i = 0; i < numEntries(); i++) {
+    if (getEntry(i)->isUse() &&
+        getEntry(i)->toUse()->virtualRegister() == input.virtualRegister()) {
+      setEntry(i, LUse(input.virtualRegister(), LUse::RECOVERED_INPUT));
+    }
+  }
+}
+
+#ifdef JS_JITSPEW
+void LNode::printName(GenericPrinter& out, Opcode op) {
+  static const char* const names[] = {
+#  define LIROP(x) #  x,
+      LIR_OPCODE_LIST(LIROP)
+#  undef LIROP
+  };
+  const char* name = names[uint32_t(op)];
+  size_t len = strlen(name);
+  for (size_t i = 0; i < len; i++) {
+    out.printf("%c", unicode::ToLowerCase(name[i]));
+  }
+}
+
+void LNode::printName(GenericPrinter& out) { printName(out, op()); }
+#endif
+
+bool LAllocation::aliases(const LAllocation& other) const {
+  if (isFloatReg() && other.isFloatReg()) {
+    return toFloatReg()->reg().aliases(other.toFloatReg()->reg());
+  }
+  return *this == other;
+}
+
+#ifdef JS_JITSPEW
+static const char* DefTypeName(LDefinition::Type type) {
+  switch (type) {
+    case LDefinition::GENERAL:
+      return "g";
+    case LDefinition::INT32:
+      return "i";
+    case LDefinition::OBJECT:
+      return "o";
+    case LDefinition::SLOTS:
+      return "s";
+    case LDefinition::FLOAT32:
+      return "f";
+    case LDefinition::DOUBLE:
+      return "d";
+    case LDefinition::SIMD128:
+      return "simd128";
+    case LDefinition::STACKRESULTS:
+      return "stackresults";
+#  ifdef JS_NUNBOX32
+    case LDefinition::TYPE:
+      return "t";
+    case LDefinition::PAYLOAD:
+      return "p";
+#  else
+    case LDefinition::BOX:
+      return "x";
+#  endif
+  }
+  MOZ_CRASH("Invalid type");
+}
+
+UniqueChars LDefinition::toString() const {
+  AutoEnterOOMUnsafeRegion oomUnsafe;
+
+  UniqueChars buf;
+  if (isBogusTemp()) {
+    buf = JS_smprintf("bogus");
+  } else {
+    buf = JS_smprintf("v%u<%s>", virtualRegister(), DefTypeName(type()));
+    if (buf) {
+      if (policy() == LDefinition::FIXED) {
+        buf = JS_sprintf_append(std::move(buf), ":%s",
+                                output()->toString().get());
+      } else if (policy() == LDefinition::MUST_REUSE_INPUT) {
+        buf = JS_sprintf_append(std::move(buf), ":tied(%u)", getReusedInput());
+      }
+    }
+  }
+
+  if (!buf) {
+    oomUnsafe.crash("LDefinition::toString()");
+  }
+
+  return buf;
+}
+
+static UniqueChars PrintUse(const LUse* use) {
+  switch (use->policy()) {
+    case LUse::REGISTER:
+      return JS_smprintf("v%u:r", use->virtualRegister());
+    case LUse::FIXED:
+      return JS_smprintf("v%u:%s", use->virtualRegister(),
+                         AnyRegister::FromCode(use->registerCode()).name());
+    case LUse::ANY:
+      return JS_smprintf("v%u:r?", use->virtualRegister());
+    case LUse::KEEPALIVE:
+      return JS_smprintf("v%u:*", use->virtualRegister());
+    case LUse::STACK:
+      return JS_smprintf("v%u:s", use->virtualRegister());
+    case LUse::RECOVERED_INPUT:
+      return JS_smprintf("v%u:**", use->virtualRegister());
+    default:
+      MOZ_CRASH("invalid use policy");
+  }
+}
+
+UniqueChars LAllocation::toString() const {
+  AutoEnterOOMUnsafeRegion oomUnsafe;
+
+  UniqueChars buf;
+  if (isBogus()) {
+    buf = JS_smprintf("bogus");
+  } else {
+    switch (kind()) {
+      case LAllocation::CONSTANT_VALUE:
+      case LAllocation::CONSTANT_INDEX:
+        buf = JS_smprintf("c");
+        break;
+      case LAllocation::GPR:
+        buf = JS_smprintf("%s", toGeneralReg()->reg().name());
+        break;
+      case LAllocation::FPU:
+        buf = JS_smprintf("%s", toFloatReg()->reg().name());
+        break;
+      case LAllocation::STACK_SLOT:
+        buf = JS_smprintf("stack:%u", toStackSlot()->slot());
+        break;
+      case LAllocation::ARGUMENT_SLOT:
+        buf = JS_smprintf("arg:%u", toArgument()->index());
+        break;
+      case LAllocation::STACK_AREA:
+        buf = JS_smprintf("stackarea:%u+%u", toStackArea()->base(),
+                          toStackArea()->size());
+        break;
+      case LAllocation::USE:
+        buf = PrintUse(toUse());
+        break;
+      default:
+        MOZ_CRASH("what?");
+    }
+  }
+
+  if (!buf) {
+    oomUnsafe.crash("LAllocation::toString()");
+  }
+
+  return buf;
+}
+
+void LAllocation::dump() const { fprintf(stderr, "%s\n", toString().get()); }
+
+void LDefinition::dump() const { fprintf(stderr, "%s\n", toString().get()); }
+
+template <typename T>
+static void PrintOperands(GenericPrinter& out, T* node) {
+  size_t numOperands = node->numOperands();
+
+  for (size_t i = 0; i < numOperands; i++) {
+    out.printf(" (%s)", node->getOperand(i)->toString().get());
+    if (i != numOperands - 1) {
+      out.printf(",");
+    }
+  }
+}
+
+void LNode::printOperands(GenericPrinter& out) {
+  if (isMoveGroup()) {
+    toMoveGroup()->printOperands(out);
+    return;
+  }
+
+  if (isPhi()) {
+    PrintOperands(out, toPhi());
+  } else {
+    PrintOperands(out, toInstruction());
+  }
+}
+#endif
+
+void LInstruction::assignSnapshot(LSnapshot* snapshot) {
+  MOZ_ASSERT(!snapshot_);
+  snapshot_ = snapshot;
+
+#ifdef JS_JITSPEW
+  if (JitSpewEnabled(JitSpew_IonSnapshots)) {
+    JitSpewHeader(JitSpew_IonSnapshots);
+    Fprinter& out = JitSpewPrinter();
+    out.printf("Assigning snapshot %p to instruction %p (", (void*)snapshot,
+               (void*)this);
+    printName(out);
+    out.printf(")\n");
+  }
+#endif
+}
+
+#ifdef JS_JITSPEW
+static size_t NumSuccessorsHelper(const LNode* ins) { return 0; }
+
+template <size_t Succs, size_t Operands, size_t Temps>
+static size_t NumSuccessorsHelper(
+    const LControlInstructionHelper<Succs, Operands, Temps>* ins) {
+  return Succs;
+}
+
+static size_t NumSuccessors(const LInstruction* ins) {
+  switch (ins->op()) {
+    default:
+      MOZ_CRASH("Unexpected LIR op");
+#  define LIROP(x)         \
+    case LNode::Opcode::x: \
+      return NumSuccessorsHelper(ins->to##x());
+      LIR_OPCODE_LIST(LIROP)
+#  undef LIROP
+  }
+}
+
+static MBasicBlock* GetSuccessorHelper(const LNode* ins, size_t i) {
+  MOZ_CRASH("Unexpected instruction with successors");
+}
+
+template <size_t Succs, size_t Operands, size_t Temps>
+static MBasicBlock* GetSuccessorHelper(
+    const LControlInstructionHelper<Succs, Operands, Temps>* ins, size_t i) {
+  return ins->getSuccessor(i);
+}
+
+static MBasicBlock* GetSuccessor(const LInstruction* ins, size_t i) {
+  MOZ_ASSERT(i < NumSuccessors(ins));
+
+  switch (ins->op()) {
+    default:
+      MOZ_CRASH("Unexpected LIR op");
+#  define LIROP(x)         \
+    case LNode::Opcode::x: \
+      return GetSuccessorHelper(ins->to##x(), i);
+      LIR_OPCODE_LIST(LIROP)
+#  undef LIROP
+  }
+}
+#endif
+
+#ifdef JS_JITSPEW
+void LNode::dump(GenericPrinter& out) {
+  if (numDefs() != 0) {
+    out.printf("{");
+    for (size_t i = 0; i < numDefs(); i++) {
+      const LDefinition* def =
+          isPhi() ? toPhi()->getDef(i) : toInstruction()->getDef(i);
+      out.printf("%s", def->toString().get());
+      if (i != numDefs() - 1) {
+        out.printf(", ");
+      }
+    }
+    out.printf("} <- ");
+  }
+
+  printName(out);
+  printOperands(out);
+
+  if (isInstruction()) {
+    LInstruction* ins = toInstruction();
+    size_t numTemps = ins->numTemps();
+    if (numTemps > 0) {
+      out.printf(" t=(");
+      for (size_t i = 0; i < numTemps; i++) {
+        out.printf("%s", ins->getTemp(i)->toString().get());
+        if (i != numTemps - 1) {
+          out.printf(", ");
+        }
+      }
+      out.printf(")");
+    }
+
+    size_t numSuccessors = NumSuccessors(ins);
+    if (numSuccessors > 0) {
+      out.printf(" s=(");
+      for (size_t i = 0; i < numSuccessors; i++) {
+        MBasicBlock* succ = GetSuccessor(ins, i);
+        out.printf("block%u", succ->id());
+        if (i != numSuccessors - 1) {
+          out.printf(", ");
+        }
+      }
+      out.printf(")");
+    }
+  }
+}
+
+void LNode::dump() {
+  Fprinter out(stderr);
+  dump(out);
+  out.printf("\n");
+  out.finish();
+}
+
+const char* LNode::getExtraName() const {
+  switch (op()) {
+    default:
+      MOZ_CRASH("Unexpected LIR op");
+#  define LIROP(x)         \
+    case LNode::Opcode::x: \
+      return to##x()->extraName();
+      LIR_OPCODE_LIST(LIROP)
+#  undef LIROP
+  }
+}
+#endif
+
+void LInstruction::initSafepoint(TempAllocator& alloc) {
+  MOZ_ASSERT(!safepoint_);
+  safepoint_ = new (alloc) LSafepoint(alloc);
+  MOZ_ASSERT(safepoint_);
+}
+
+bool LMoveGroup::add(LAllocation from, LAllocation to, LDefinition::Type type) {
+#ifdef DEBUG
+  MOZ_ASSERT(from != to);
+  for (size_t i = 0; i < moves_.length(); i++) {
+    MOZ_ASSERT(to != moves_[i].to());
+  }
+
+  // Check that SIMD moves are aligned according to ABI requirements.
+#  ifdef ENABLE_WASM_SIMD
+  // Alignment is not currently required for SIMD on x86/x64.  See also
+  // CodeGeneratorShared::CodeGeneratorShared and in general everywhere
+  // SimdMemoryAignment is used.  Likely, alignment requirements will return.
+#    if !defined(JS_CODEGEN_X86) && !defined(JS_CODEGEN_X64)
+  if (LDefinition(type).type() == LDefinition::SIMD128) {
+    MOZ_ASSERT(from.isMemory() || from.isFloatReg());
+    if (from.isMemory()) {
+      if (from.isArgument()) {
+        MOZ_ASSERT(from.toArgument()->index() % SimdMemoryAlignment == 0);
+      } else {
+        MOZ_ASSERT(from.toStackSlot()->slot() % SimdMemoryAlignment == 0);
+      }
+    }
+    MOZ_ASSERT(to.isMemory() || to.isFloatReg());
+    if (to.isMemory()) {
+      if (to.isArgument()) {
+        MOZ_ASSERT(to.toArgument()->index() % SimdMemoryAlignment == 0);
+      } else {
+        MOZ_ASSERT(to.toStackSlot()->slot() % SimdMemoryAlignment == 0);
+      }
+    }
+  }
+#    endif
+#  endif
+#endif
+  return moves_.append(LMove(from, to, type));
+}
+
+bool LMoveGroup::addAfter(LAllocation from, LAllocation to,
+                          LDefinition::Type type) {
+  // Transform the operands to this move so that performing the result
+  // simultaneously with existing moves in the group will have the same
+  // effect as if the original move took place after the existing moves.
+
+  for (size_t i = 0; i < moves_.length(); i++) {
+    if (moves_[i].to() == from) {
+      from = moves_[i].from();
+      break;
+    }
+  }
+
+  if (from == to) {
+    return true;
+  }
+
+  for (size_t i = 0; i < moves_.length(); i++) {
+    if (to == moves_[i].to()) {
+      moves_[i] = LMove(from, to, type);
+      return true;
+    }
+  }
+
+  return add(from, to, type);
+}
+
+#ifdef JS_JITSPEW
+void LMoveGroup::printOperands(GenericPrinter& out) {
+  for (size_t i = 0; i < numMoves(); i++) {
+    const LMove& move = getMove(i);
+    out.printf(" [%s -> %s", move.from().toString().get(),
+               move.to().toString().get());
+    out.printf(", %s", DefTypeName(move.type()));
+    out.printf("]");
+    if (i != numMoves() - 1) {
+      out.printf(",");
+    }
+  }
+}
+#endif
+
+#define LIROP(x)                              \
+  static_assert(!std::is_polymorphic_v<L##x>, \
+                "LIR instructions should not have virtual methods");
+LIR_OPCODE_LIST(LIROP)
+#undef LIROP