xref: /external/v8/src/x64/lithium-codegen-x64.cc

// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#if defined(V8_TARGET_ARCH_X64)

#include "x64/lithium-codegen-x64.h"
#include "code-stubs.h"
#include "stub-cache.h"

namespace v8 {
namespace internal {


// When invoking builtins, we need to record the safepoint in the middle of
// the invoke instruction sequence generated by the macro assembler.
class SafepointGenerator : public CallWrapper {
 public:
  SafepointGenerator(LCodeGen* codegen,
                     LPointerMap* pointers,
                     int deoptimization_index)
      : codegen_(codegen),
        pointers_(pointers),
        deoptimization_index_(deoptimization_index) { }
  virtual ~SafepointGenerator() { }

  virtual void BeforeCall(int call_size) {
    ASSERT(call_size >= 0);
    // Ensure that we have enough space after the previous safepoint position
    // for the jump generated there.
    int call_end = codegen_->masm()->pc_offset() + call_size;
    int prev_jump_end = codegen_->LastSafepointEnd() + kMinSafepointSize;
    if (call_end < prev_jump_end) {
      int padding_size = prev_jump_end - call_end;
      STATIC_ASSERT(kMinSafepointSize <= 9);  // One multibyte nop is enough.
      codegen_->masm()->nop(padding_size);
    }
  }

  virtual void AfterCall() {
    codegen_->RecordSafepoint(pointers_, deoptimization_index_);
  }

 private:
  static const int kMinSafepointSize =
      MacroAssembler::kShortCallInstructionLength;
  LCodeGen* codegen_;
  LPointerMap* pointers_;
  int deoptimization_index_;
};


#define __ masm()->

bool LCodeGen::GenerateCode() {
  HPhase phase("Code generation", chunk());
  ASSERT(is_unused());
  status_ = GENERATING;
  return GeneratePrologue() &&
      GenerateBody() &&
      GenerateDeferredCode() &&
      GenerateJumpTable() &&
      GenerateSafepointTable();
}


void LCodeGen::FinishCode(Handle<Code> code) {
  ASSERT(is_done());
  code->set_stack_slots(StackSlotCount());
  code->set_safepoint_table_offset(safepoints_.GetCodeOffset());
  PopulateDeoptimizationData(code);
  Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(code);
}


void LCodeGen::Abort(const char* format, ...) {
  if (FLAG_trace_bailout) {
    SmartPointer<char> name(info()->shared_info()->DebugName()->ToCString());
    PrintF("Aborting LCodeGen in @\"%s\": ", *name);
    va_list arguments;
    va_start(arguments, format);
    OS::VPrint(format, arguments);
    va_end(arguments);
    PrintF("\n");
  }
  status_ = ABORTED;
}


void LCodeGen::Comment(const char* format, ...) {
  if (!FLAG_code_comments) return;
  char buffer[4 * KB];
  StringBuilder builder(buffer, ARRAY_SIZE(buffer));
  va_list arguments;
  va_start(arguments, format);
  builder.AddFormattedList(format, arguments);
  va_end(arguments);

  // Copy the string before recording it in the assembler to avoid
  // issues when the stack allocated buffer goes out of scope.
  int length = builder.position();
  Vector<char> copy = Vector<char>::New(length + 1);
  memcpy(copy.start(), builder.Finalize(), copy.length());
  masm()->RecordComment(copy.start());
}


bool LCodeGen::GeneratePrologue() {
  ASSERT(is_generating());

#ifdef DEBUG
  if (strlen(FLAG_stop_at) > 0 &&
      info_->function()->name()->IsEqualTo(CStrVector(FLAG_stop_at))) {
    __ int3();
  }
#endif

  __ push(rbp);  // Caller's frame pointer.
  __ movq(rbp, rsp);
  __ push(rsi);  // Callee's context.
  __ push(rdi);  // Callee's JS function.

  // Reserve space for the stack slots needed by the code.
  int slots = StackSlotCount();
  if (slots > 0) {
    if (FLAG_debug_code) {
      __ Set(rax, slots);
      __ movq(kScratchRegister, kSlotsZapValue, RelocInfo::NONE);
      Label loop;
      __ bind(&loop);
      __ push(kScratchRegister);
      __ decl(rax);
      __ j(not_zero, &loop);
    } else {
      __ subq(rsp, Immediate(slots * kPointerSize));
#ifdef _MSC_VER
      // On windows, you may not access the stack more than one page below
      // the most recently mapped page. To make the allocated area randomly
      // accessible, we write to each page in turn (the value is irrelevant).
      const int kPageSize = 4 * KB;
      for (int offset = slots * kPointerSize - kPageSize;
           offset > 0;
           offset -= kPageSize) {
        __ movq(Operand(rsp, offset), rax);
      }
#endif
    }
  }

  // Possibly allocate a local context.
  int heap_slots = scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
  if (heap_slots > 0) {
    Comment(";;; Allocate local context");
    // Argument to NewContext is the function, which is still in rdi.
    __ push(rdi);
    if (heap_slots <= FastNewContextStub::kMaximumSlots) {
      FastNewContextStub stub(heap_slots);
      __ CallStub(&stub);
    } else {
      __ CallRuntime(Runtime::kNewContext, 1);
    }
    RecordSafepoint(Safepoint::kNoDeoptimizationIndex);
    // Context is returned in both rax and rsi.  It replaces the context
    // passed to us.  It's saved in the stack and kept live in rsi.
    __ movq(Operand(rbp, StandardFrameConstants::kContextOffset), rsi);

    // Copy any necessary parameters into the context.
    int num_parameters = scope()->num_parameters();
    for (int i = 0; i < num_parameters; i++) {
      Slot* slot = scope()->parameter(i)->AsSlot();
      if (slot != NULL && slot->type() == Slot::CONTEXT) {
        int parameter_offset = StandardFrameConstants::kCallerSPOffset +
            (num_parameters - 1 - i) * kPointerSize;
        // Load parameter from stack.
        __ movq(rax, Operand(rbp, parameter_offset));
        // Store it in the context.
        int context_offset = Context::SlotOffset(slot->index());
        __ movq(Operand(rsi, context_offset), rax);
        // Update the write barrier. This clobbers all involved
        // registers, so we have use a third register to avoid
        // clobbering rsi.
        __ movq(rcx, rsi);
        __ RecordWrite(rcx, context_offset, rax, rbx);
      }
    }
    Comment(";;; End allocate local context");
  }

  // Trace the call.
  if (FLAG_trace) {
    __ CallRuntime(Runtime::kTraceEnter, 0);
  }
  return !is_aborted();
}


bool LCodeGen::GenerateBody() {
  ASSERT(is_generating());
  bool emit_instructions = true;
  for (current_instruction_ = 0;
       !is_aborted() && current_instruction_ < instructions_->length();
       current_instruction_++) {
    LInstruction* instr = instructions_->at(current_instruction_);
    if (instr->IsLabel()) {
      LLabel* label = LLabel::cast(instr);
      emit_instructions = !label->HasReplacement();
    }

    if (emit_instructions) {
      Comment(";;; @%d: %s.", current_instruction_, instr->Mnemonic());
      instr->CompileToNative(this);
    }
  }
  return !is_aborted();
}


LInstruction* LCodeGen::GetNextInstruction() {
  if (current_instruction_ < instructions_->length() - 1) {
    return instructions_->at(current_instruction_ + 1);
  } else {
    return NULL;
  }
}


bool LCodeGen::GenerateJumpTable() {
  for (int i = 0; i < jump_table_.length(); i++) {
    __ bind(&jump_table_[i].label);
    __ Jump(jump_table_[i].address, RelocInfo::RUNTIME_ENTRY);
  }
  return !is_aborted();
}


bool LCodeGen::GenerateDeferredCode() {
  ASSERT(is_generating());
  for (int i = 0; !is_aborted() && i < deferred_.length(); i++) {
    LDeferredCode* code = deferred_[i];
    __ bind(code->entry());
    code->Generate();
    __ jmp(code->exit());
  }

  // Deferred code is the last part of the instruction sequence. Mark
  // the generated code as done unless we bailed out.
  if (!is_aborted()) status_ = DONE;
  return !is_aborted();
}


bool LCodeGen::GenerateSafepointTable() {
  ASSERT(is_done());
  // Ensure that there is space at the end of the code to write a number
  // of jump instructions, as well as to afford writing a call near the end
  // of the code.
  // The jumps are used when there isn't room in the code stream to write
  // a long call instruction. Instead it writes a shorter call to a
  // jump instruction in the same code object.
  // The calls are used when lazy deoptimizing a function and calls to a
  // deoptimization function.
  int short_deopts = safepoints_.CountShortDeoptimizationIntervals(
      static_cast<unsigned>(MacroAssembler::kJumpInstructionLength));
  int byte_count = (short_deopts) * MacroAssembler::kJumpInstructionLength;
  while (byte_count-- > 0) {
    __ int3();
  }
  safepoints_.Emit(masm(), StackSlotCount());
  return !is_aborted();
}


Register LCodeGen::ToRegister(int index) const {
  return Register::FromAllocationIndex(index);
}


XMMRegister LCodeGen::ToDoubleRegister(int index) const {
  return XMMRegister::FromAllocationIndex(index);
}


Register LCodeGen::ToRegister(LOperand* op) const {
  ASSERT(op->IsRegister());
  return ToRegister(op->index());
}


XMMRegister LCodeGen::ToDoubleRegister(LOperand* op) const {
  ASSERT(op->IsDoubleRegister());
  return ToDoubleRegister(op->index());
}


bool LCodeGen::IsInteger32Constant(LConstantOperand* op) const {
  return op->IsConstantOperand() &&
      chunk_->LookupLiteralRepresentation(op).IsInteger32();
}


bool LCodeGen::IsTaggedConstant(LConstantOperand* op) const {
  return op->IsConstantOperand() &&
      chunk_->LookupLiteralRepresentation(op).IsTagged();
}


int LCodeGen::ToInteger32(LConstantOperand* op) const {
  Handle<Object> value = chunk_->LookupLiteral(op);
  ASSERT(chunk_->LookupLiteralRepresentation(op).IsInteger32());
  ASSERT(static_cast<double>(static_cast<int32_t>(value->Number())) ==
      value->Number());
  return static_cast<int32_t>(value->Number());
}


Handle<Object> LCodeGen::ToHandle(LConstantOperand* op) const {
  Handle<Object> literal = chunk_->LookupLiteral(op);
  ASSERT(chunk_->LookupLiteralRepresentation(op).IsTagged());
  return literal;
}


Operand LCodeGen::ToOperand(LOperand* op) const {
  // Does not handle registers. In X64 assembler, plain registers are not
  // representable as an Operand.
  ASSERT(op->IsStackSlot() || op->IsDoubleStackSlot());
  int index = op->index();
  if (index >= 0) {
    // Local or spill slot. Skip the frame pointer, function, and
    // context in the fixed part of the frame.
    return Operand(rbp, -(index + 3) * kPointerSize);
  } else {
    // Incoming parameter. Skip the return address.
    return Operand(rbp, -(index - 1) * kPointerSize);
  }
}


void LCodeGen::WriteTranslation(LEnvironment* environment,
                                Translation* translation) {
  if (environment == NULL) return;

  // The translation includes one command per value in the environment.
  int translation_size = environment->values()->length();
  // The output frame height does not include the parameters.
  int height = translation_size - environment->parameter_count();

  WriteTranslation(environment->outer(), translation);
  int closure_id = DefineDeoptimizationLiteral(environment->closure());
  translation->BeginFrame(environment->ast_id(), closure_id, height);
  for (int i = 0; i < translation_size; ++i) {
    LOperand* value = environment->values()->at(i);
    // spilled_registers_ and spilled_double_registers_ are either
    // both NULL or both set.
    if (environment->spilled_registers() != NULL && value != NULL) {
      if (value->IsRegister() &&
          environment->spilled_registers()[value->index()] != NULL) {
        translation->MarkDuplicate();
        AddToTranslation(translation,
                         environment->spilled_registers()[value->index()],
                         environment->HasTaggedValueAt(i));
      } else if (
          value->IsDoubleRegister() &&
          environment->spilled_double_registers()[value->index()] != NULL) {
        translation->MarkDuplicate();
        AddToTranslation(
            translation,
            environment->spilled_double_registers()[value->index()],
            false);
      }
    }

    AddToTranslation(translation, value, environment->HasTaggedValueAt(i));
  }
}


void LCodeGen::AddToTranslation(Translation* translation,
                                LOperand* op,
                                bool is_tagged) {
  if (op == NULL) {
    // TODO(twuerthinger): Introduce marker operands to indicate that this value
    // is not present and must be reconstructed from the deoptimizer. Currently
    // this is only used for the arguments object.
    translation->StoreArgumentsObject();
  } else if (op->IsStackSlot()) {
    if (is_tagged) {
      translation->StoreStackSlot(op->index());
    } else {
      translation->StoreInt32StackSlot(op->index());
    }
  } else if (op->IsDoubleStackSlot()) {
    translation->StoreDoubleStackSlot(op->index());
  } else if (op->IsArgument()) {
    ASSERT(is_tagged);
    int src_index = StackSlotCount() + op->index();
    translation->StoreStackSlot(src_index);
  } else if (op->IsRegister()) {
    Register reg = ToRegister(op);
    if (is_tagged) {
      translation->StoreRegister(reg);
    } else {
      translation->StoreInt32Register(reg);
    }
  } else if (op->IsDoubleRegister()) {
    XMMRegister reg = ToDoubleRegister(op);
    translation->StoreDoubleRegister(reg);
  } else if (op->IsConstantOperand()) {
    Handle<Object> literal = chunk()->LookupLiteral(LConstantOperand::cast(op));
    int src_index = DefineDeoptimizationLiteral(literal);
    translation->StoreLiteral(src_index);
  } else {
    UNREACHABLE();
  }
}


void LCodeGen::CallCodeGeneric(Handle<Code> code,
                               RelocInfo::Mode mode,
                               LInstruction* instr,
                               SafepointMode safepoint_mode,
                               int argc) {
  ASSERT(instr != NULL);
  LPointerMap* pointers = instr->pointer_map();
  RecordPosition(pointers->position());
  __ call(code, mode);
  RegisterLazyDeoptimization(instr, safepoint_mode, argc);

  // Signal that we don't inline smi code before these stubs in the
  // optimizing code generator.
  if (code->kind() == Code::TYPE_RECORDING_BINARY_OP_IC ||
      code->kind() == Code::COMPARE_IC) {
    __ nop();
  }
}


void LCodeGen::CallCode(Handle<Code> code,
                        RelocInfo::Mode mode,
                        LInstruction* instr) {
  CallCodeGeneric(code, mode, instr, RECORD_SIMPLE_SAFEPOINT, 0);
}


void LCodeGen::CallRuntime(const Runtime::Function* function,
                           int num_arguments,
                           LInstruction* instr) {
  ASSERT(instr != NULL);
  ASSERT(instr->HasPointerMap());
  LPointerMap* pointers = instr->pointer_map();
  RecordPosition(pointers->position());

  __ CallRuntime(function, num_arguments);
  RegisterLazyDeoptimization(instr, RECORD_SIMPLE_SAFEPOINT, 0);
}


void LCodeGen::CallRuntimeFromDeferred(Runtime::FunctionId id,
                                       int argc,
                                       LInstruction* instr) {
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
  __ CallRuntimeSaveDoubles(id);
  RecordSafepointWithRegisters(
      instr->pointer_map(), argc, Safepoint::kNoDeoptimizationIndex);
}


void LCodeGen::RegisterLazyDeoptimization(LInstruction* instr,
                                          SafepointMode safepoint_mode,
                                          int argc) {
  // Create the environment to bailout to. If the call has side effects
  // execution has to continue after the call otherwise execution can continue
  // from a previous bailout point repeating the call.
  LEnvironment* deoptimization_environment;
  if (instr->HasDeoptimizationEnvironment()) {
    deoptimization_environment = instr->deoptimization_environment();
  } else {
    deoptimization_environment = instr->environment();
  }

  RegisterEnvironmentForDeoptimization(deoptimization_environment);
  if (safepoint_mode == RECORD_SIMPLE_SAFEPOINT) {
    ASSERT(argc == 0);
    RecordSafepoint(instr->pointer_map(),
                    deoptimization_environment->deoptimization_index());
  } else {
    ASSERT(safepoint_mode == RECORD_SAFEPOINT_WITH_REGISTERS);
    RecordSafepointWithRegisters(
        instr->pointer_map(),
        argc,
        deoptimization_environment->deoptimization_index());
  }
}


void LCodeGen::RegisterEnvironmentForDeoptimization(LEnvironment* environment) {
  if (!environment->HasBeenRegistered()) {
    // Physical stack frame layout:
    // -x ............. -4  0 ..................................... y
    // [incoming arguments] [spill slots] [pushed outgoing arguments]

    // Layout of the environment:
    // 0 ..................................................... size-1
    // [parameters] [locals] [expression stack including arguments]

    // Layout of the translation:
    // 0 ........................................................ size - 1 + 4
    // [expression stack including arguments] [locals] [4 words] [parameters]
    // |>------------  translation_size ------------<|

    int frame_count = 0;
    for (LEnvironment* e = environment; e != NULL; e = e->outer()) {
      ++frame_count;
    }
    Translation translation(&translations_, frame_count);
    WriteTranslation(environment, &translation);
    int deoptimization_index = deoptimizations_.length();
    environment->Register(deoptimization_index, translation.index());
    deoptimizations_.Add(environment);
  }
}


void LCodeGen::DeoptimizeIf(Condition cc, LEnvironment* environment) {
  RegisterEnvironmentForDeoptimization(environment);
  ASSERT(environment->HasBeenRegistered());
  int id = environment->deoptimization_index();
  Address entry = Deoptimizer::GetDeoptimizationEntry(id, Deoptimizer::EAGER);
  ASSERT(entry != NULL);
  if (entry == NULL) {
    Abort("bailout was not prepared");
    return;
  }

  if (cc == no_condition) {
    __ Jump(entry, RelocInfo::RUNTIME_ENTRY);
  } else {
    // We often have several deopts to the same entry, reuse the last
    // jump entry if this is the case.
    if (jump_table_.is_empty() ||
        jump_table_.last().address != entry) {
      jump_table_.Add(JumpTableEntry(entry));
    }
    __ j(cc, &jump_table_.last().label);
  }
}


void LCodeGen::PopulateDeoptimizationData(Handle<Code> code) {
  int length = deoptimizations_.length();
  if (length == 0) return;
  ASSERT(FLAG_deopt);
  Handle<DeoptimizationInputData> data =
      factory()->NewDeoptimizationInputData(length, TENURED);

  Handle<ByteArray> translations = translations_.CreateByteArray();
  data->SetTranslationByteArray(*translations);
  data->SetInlinedFunctionCount(Smi::FromInt(inlined_function_count_));

  Handle<FixedArray> literals =
      factory()->NewFixedArray(deoptimization_literals_.length(), TENURED);
  for (int i = 0; i < deoptimization_literals_.length(); i++) {
    literals->set(i, *deoptimization_literals_[i]);
  }
  data->SetLiteralArray(*literals);

  data->SetOsrAstId(Smi::FromInt(info_->osr_ast_id()));
  data->SetOsrPcOffset(Smi::FromInt(osr_pc_offset_));

  // Populate the deoptimization entries.
  for (int i = 0; i < length; i++) {
    LEnvironment* env = deoptimizations_[i];
    data->SetAstId(i, Smi::FromInt(env->ast_id()));
    data->SetTranslationIndex(i, Smi::FromInt(env->translation_index()));
    data->SetArgumentsStackHeight(i,
                                  Smi::FromInt(env->arguments_stack_height()));
  }
  code->set_deoptimization_data(*data);
}


int LCodeGen::DefineDeoptimizationLiteral(Handle<Object> literal) {
  int result = deoptimization_literals_.length();
  for (int i = 0; i < deoptimization_literals_.length(); ++i) {
    if (deoptimization_literals_[i].is_identical_to(literal)) return i;
  }
  deoptimization_literals_.Add(literal);
  return result;
}


void LCodeGen::PopulateDeoptimizationLiteralsWithInlinedFunctions() {
  ASSERT(deoptimization_literals_.length() == 0);

  const ZoneList<Handle<JSFunction> >* inlined_closures =
      chunk()->inlined_closures();

  for (int i = 0, length = inlined_closures->length();
       i < length;
       i++) {
    DefineDeoptimizationLiteral(inlined_closures->at(i));
  }

  inlined_function_count_ = deoptimization_literals_.length();
}


void LCodeGen::RecordSafepoint(
    LPointerMap* pointers,
    Safepoint::Kind kind,
    int arguments,
    int deoptimization_index) {
  ASSERT(kind == expected_safepoint_kind_);

  const ZoneList<LOperand*>* operands = pointers->operands();

  Safepoint safepoint = safepoints_.DefineSafepoint(masm(),
      kind, arguments, deoptimization_index);
  for (int i = 0; i < operands->length(); i++) {
    LOperand* pointer = operands->at(i);
    if (pointer->IsStackSlot()) {
      safepoint.DefinePointerSlot(pointer->index());
    } else if (pointer->IsRegister() && (kind & Safepoint::kWithRegisters)) {
      safepoint.DefinePointerRegister(ToRegister(pointer));
    }
  }
  if (kind & Safepoint::kWithRegisters) {
    // Register rsi always contains a pointer to the context.
    safepoint.DefinePointerRegister(rsi);
  }
}


void LCodeGen::RecordSafepoint(LPointerMap* pointers,
                               int deoptimization_index) {
  RecordSafepoint(pointers, Safepoint::kSimple, 0, deoptimization_index);
}


void LCodeGen::RecordSafepoint(int deoptimization_index) {
  LPointerMap empty_pointers(RelocInfo::kNoPosition);
  RecordSafepoint(&empty_pointers, deoptimization_index);
}


void LCodeGen::RecordSafepointWithRegisters(LPointerMap* pointers,
                                            int arguments,
                                            int deoptimization_index) {
  RecordSafepoint(pointers, Safepoint::kWithRegisters, arguments,
      deoptimization_index);
}


void LCodeGen::RecordPosition(int position) {
  if (!FLAG_debug_info || position == RelocInfo::kNoPosition) return;
  masm()->positions_recorder()->RecordPosition(position);
}


void LCodeGen::DoLabel(LLabel* label) {
  if (label->is_loop_header()) {
    Comment(";;; B%d - LOOP entry", label->block_id());
  } else {
    Comment(";;; B%d", label->block_id());
  }
  __ bind(label->label());
  current_block_ = label->block_id();
  LCodeGen::DoGap(label);
}


void LCodeGen::DoParallelMove(LParallelMove* move) {
  resolver_.Resolve(move);
}


void LCodeGen::DoGap(LGap* gap) {
  for (int i = LGap::FIRST_INNER_POSITION;
       i <= LGap::LAST_INNER_POSITION;
       i++) {
    LGap::InnerPosition inner_pos = static_cast<LGap::InnerPosition>(i);
    LParallelMove* move = gap->GetParallelMove(inner_pos);
    if (move != NULL) DoParallelMove(move);
  }

  LInstruction* next = GetNextInstruction();
  if (next != NULL && next->IsLazyBailout()) {
    int pc = masm()->pc_offset();
    safepoints_.SetPcAfterGap(pc);
  }
}


void LCodeGen::DoParameter(LParameter* instr) {
  // Nothing to do.
}


void LCodeGen::DoCallStub(LCallStub* instr) {
  ASSERT(ToRegister(instr->result()).is(rax));
  switch (instr->hydrogen()->major_key()) {
    case CodeStub::RegExpConstructResult: {
      RegExpConstructResultStub stub;
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    case CodeStub::RegExpExec: {
      RegExpExecStub stub;
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    case CodeStub::SubString: {
      SubStringStub stub;
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    case CodeStub::NumberToString: {
      NumberToStringStub stub;
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    case CodeStub::StringAdd: {
      StringAddStub stub(NO_STRING_ADD_FLAGS);
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    case CodeStub::StringCompare: {
      StringCompareStub stub;
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    case CodeStub::TranscendentalCache: {
      TranscendentalCacheStub stub(instr->transcendental_type(),
                                   TranscendentalCacheStub::TAGGED);
      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
      break;
    }
    default:
      UNREACHABLE();
  }
}


void LCodeGen::DoUnknownOSRValue(LUnknownOSRValue* instr) {
  // Nothing to do.
}


void LCodeGen::DoModI(LModI* instr) {
  if (instr->hydrogen()->HasPowerOf2Divisor()) {
    Register dividend = ToRegister(instr->InputAt(0));

    int32_t divisor =
        HConstant::cast(instr->hydrogen()->right())->Integer32Value();

    if (divisor < 0) divisor = -divisor;

    NearLabel positive_dividend, done;
    __ testl(dividend, dividend);
    __ j(not_sign, &positive_dividend);
    __ negl(dividend);
    __ andl(dividend, Immediate(divisor - 1));
    __ negl(dividend);
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      __ j(not_zero, &done);
      DeoptimizeIf(no_condition, instr->environment());
    } else {
      __ jmp(&done);
    }
    __ bind(&positive_dividend);
    __ andl(dividend, Immediate(divisor - 1));
    __ bind(&done);
  } else {
    LOperand* right = instr->InputAt(1);
    Register right_reg = ToRegister(right);

    ASSERT(ToRegister(instr->result()).is(rdx));
    ASSERT(ToRegister(instr->InputAt(0)).is(rax));
    ASSERT(!right_reg.is(rax));
    ASSERT(!right_reg.is(rdx));

    // Check for x % 0.
    if (instr->hydrogen()->CheckFlag(HValue::kCanBeDivByZero)) {
      __ testl(right_reg, right_reg);
      DeoptimizeIf(zero, instr->environment());
    }

    // Sign extend eax to edx.
    // (We are using only the low 32 bits of the values.)
    __ cdq();

    // Check for (0 % -x) that will produce negative zero.
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      NearLabel positive_left;
      NearLabel done;
      __ testl(rax, rax);
      __ j(not_sign, &positive_left);
      __ idivl(right_reg);

      // Test the remainder for 0, because then the result would be -0.
      __ testl(rdx, rdx);
      __ j(not_zero, &done);

      DeoptimizeIf(no_condition, instr->environment());
      __ bind(&positive_left);
      __ idivl(right_reg);
      __ bind(&done);
    } else {
      __ idivl(right_reg);
    }
  }
}


void LCodeGen::DoDivI(LDivI* instr) {
  LOperand* right = instr->InputAt(1);
  ASSERT(ToRegister(instr->result()).is(rax));
  ASSERT(ToRegister(instr->InputAt(0)).is(rax));
  ASSERT(!ToRegister(instr->InputAt(1)).is(rax));
  ASSERT(!ToRegister(instr->InputAt(1)).is(rdx));

  Register left_reg = rax;

  // Check for x / 0.
  Register right_reg = ToRegister(right);
  if (instr->hydrogen()->CheckFlag(HValue::kCanBeDivByZero)) {
    __ testl(right_reg, right_reg);
    DeoptimizeIf(zero, instr->environment());
  }

  // Check for (0 / -x) that will produce negative zero.
  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
    NearLabel left_not_zero;
    __ testl(left_reg, left_reg);
    __ j(not_zero, &left_not_zero);
    __ testl(right_reg, right_reg);
    DeoptimizeIf(sign, instr->environment());
    __ bind(&left_not_zero);
  }

  // Check for (-kMinInt / -1).
  if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
    NearLabel left_not_min_int;
    __ cmpl(left_reg, Immediate(kMinInt));
    __ j(not_zero, &left_not_min_int);
    __ cmpl(right_reg, Immediate(-1));
    DeoptimizeIf(zero, instr->environment());
    __ bind(&left_not_min_int);
  }

  // Sign extend to rdx.
  __ cdq();
  __ idivl(right_reg);

  // Deoptimize if remainder is not 0.
  __ testl(rdx, rdx);
  DeoptimizeIf(not_zero, instr->environment());
}


void LCodeGen::DoMulI(LMulI* instr) {
  Register left = ToRegister(instr->InputAt(0));
  LOperand* right = instr->InputAt(1);

  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
    __ movl(kScratchRegister, left);
  }

  bool can_overflow =
      instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
  if (right->IsConstantOperand()) {
    int right_value = ToInteger32(LConstantOperand::cast(right));
    if (right_value == -1) {
      __ negl(left);
    } else if (right_value == 0) {
      __ xorl(left, left);
    } else if (right_value == 2) {
      __ addl(left, left);
    } else if (!can_overflow) {
      // If the multiplication is known to not overflow, we
      // can use operations that don't set the overflow flag
      // correctly.
      switch (right_value) {
        case 1:
          // Do nothing.
          break;
        case 3:
          __ leal(left, Operand(left, left, times_2, 0));
          break;
        case 4:
          __ shll(left, Immediate(2));
          break;
        case 5:
          __ leal(left, Operand(left, left, times_4, 0));
          break;
        case 8:
          __ shll(left, Immediate(3));
          break;
        case 9:
          __ leal(left, Operand(left, left, times_8, 0));
          break;
        case 16:
          __ shll(left, Immediate(4));
          break;
        default:
          __ imull(left, left, Immediate(right_value));
          break;
      }
    } else {
      __ imull(left, left, Immediate(right_value));
    }
  } else if (right->IsStackSlot()) {
    __ imull(left, ToOperand(right));
  } else {
    __ imull(left, ToRegister(right));
  }

  if (can_overflow) {
    DeoptimizeIf(overflow, instr->environment());
  }

  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
    // Bail out if the result is supposed to be negative zero.
    NearLabel done;
    __ testl(left, left);
    __ j(not_zero, &done);
    if (right->IsConstantOperand()) {
      if (ToInteger32(LConstantOperand::cast(right)) <= 0) {
        DeoptimizeIf(no_condition, instr->environment());
      }
    } else if (right->IsStackSlot()) {
      __ or_(kScratchRegister, ToOperand(right));
      DeoptimizeIf(sign, instr->environment());
    } else {
      // Test the non-zero operand for negative sign.
      __ or_(kScratchRegister, ToRegister(right));
      DeoptimizeIf(sign, instr->environment());
    }
    __ bind(&done);
  }
}


void LCodeGen::DoBitI(LBitI* instr) {
  LOperand* left = instr->InputAt(0);
  LOperand* right = instr->InputAt(1);
  ASSERT(left->Equals(instr->result()));
  ASSERT(left->IsRegister());

  if (right->IsConstantOperand()) {
    int right_operand = ToInteger32(LConstantOperand::cast(right));
    switch (instr->op()) {
      case Token::BIT_AND:
        __ andl(ToRegister(left), Immediate(right_operand));
        break;
      case Token::BIT_OR:
        __ orl(ToRegister(left), Immediate(right_operand));
        break;
      case Token::BIT_XOR:
        __ xorl(ToRegister(left), Immediate(right_operand));
        break;
      default:
        UNREACHABLE();
        break;
    }
  } else if (right->IsStackSlot()) {
    switch (instr->op()) {
      case Token::BIT_AND:
        __ andl(ToRegister(left), ToOperand(right));
        break;
      case Token::BIT_OR:
        __ orl(ToRegister(left), ToOperand(right));
        break;
      case Token::BIT_XOR:
        __ xorl(ToRegister(left), ToOperand(right));
        break;
      default:
        UNREACHABLE();
        break;
    }
  } else {
    ASSERT(right->IsRegister());
    switch (instr->op()) {
      case Token::BIT_AND:
        __ andl(ToRegister(left), ToRegister(right));
        break;
      case Token::BIT_OR:
        __ orl(ToRegister(left), ToRegister(right));
        break;
      case Token::BIT_XOR:
        __ xorl(ToRegister(left), ToRegister(right));
        break;
      default:
        UNREACHABLE();
        break;
    }
  }
}


void LCodeGen::DoShiftI(LShiftI* instr) {
  LOperand* left = instr->InputAt(0);
  LOperand* right = instr->InputAt(1);
  ASSERT(left->Equals(instr->result()));
  ASSERT(left->IsRegister());
  if (right->IsRegister()) {
    ASSERT(ToRegister(right).is(rcx));

    switch (instr->op()) {
      case Token::SAR:
        __ sarl_cl(ToRegister(left));
        break;
      case Token::SHR:
        __ shrl_cl(ToRegister(left));
        if (instr->can_deopt()) {
          __ testl(ToRegister(left), ToRegister(left));
          DeoptimizeIf(negative, instr->environment());
        }
        break;
      case Token::SHL:
        __ shll_cl(ToRegister(left));
        break;
      default:
        UNREACHABLE();
        break;
    }
  } else {
    int value = ToInteger32(LConstantOperand::cast(right));
    uint8_t shift_count = static_cast<uint8_t>(value & 0x1F);
    switch (instr->op()) {
      case Token::SAR:
        if (shift_count != 0) {
          __ sarl(ToRegister(left), Immediate(shift_count));
        }
        break;
      case Token::SHR:
        if (shift_count == 0 && instr->can_deopt()) {
          __ testl(ToRegister(left), ToRegister(left));
          DeoptimizeIf(negative, instr->environment());
        } else {
          __ shrl(ToRegister(left), Immediate(shift_count));
        }
        break;
      case Token::SHL:
        if (shift_count != 0) {
          __ shll(ToRegister(left), Immediate(shift_count));
        }
        break;
      default:
        UNREACHABLE();
        break;
    }
  }
}


void LCodeGen::DoSubI(LSubI* instr) {
  LOperand* left = instr->InputAt(0);
  LOperand* right = instr->InputAt(1);
  ASSERT(left->Equals(instr->result()));

  if (right->IsConstantOperand()) {
    __ subl(ToRegister(left),
            Immediate(ToInteger32(LConstantOperand::cast(right))));
  } else if (right->IsRegister()) {
    __ subl(ToRegister(left), ToRegister(right));
  } else {
    __ subl(ToRegister(left), ToOperand(right));
  }

  if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
    DeoptimizeIf(overflow, instr->environment());
  }
}


void LCodeGen::DoConstantI(LConstantI* instr) {
  ASSERT(instr->result()->IsRegister());
  __ Set(ToRegister(instr->result()), instr->value());
}


void LCodeGen::DoConstantD(LConstantD* instr) {
  ASSERT(instr->result()->IsDoubleRegister());
  XMMRegister res = ToDoubleRegister(instr->result());
  double v = instr->value();
  uint64_t int_val = BitCast<uint64_t, double>(v);
  // Use xor to produce +0.0 in a fast and compact way, but avoid to
  // do so if the constant is -0.0.
  if (int_val == 0) {
    __ xorpd(res, res);
  } else {
    Register tmp = ToRegister(instr->TempAt(0));
    __ Set(tmp, int_val);
    __ movq(res, tmp);
  }
}


void LCodeGen::DoConstantT(LConstantT* instr) {
  ASSERT(instr->result()->IsRegister());
  __ Move(ToRegister(instr->result()), instr->value());
}


void LCodeGen::DoJSArrayLength(LJSArrayLength* instr) {
  Register result = ToRegister(instr->result());
  Register array = ToRegister(instr->InputAt(0));
  __ movq(result, FieldOperand(array, JSArray::kLengthOffset));
}


void LCodeGen::DoFixedArrayLength(LFixedArrayLength* instr) {
  Register result = ToRegister(instr->result());
  Register array = ToRegister(instr->InputAt(0));
  __ movq(result, FieldOperand(array, FixedArray::kLengthOffset));
}


void LCodeGen::DoExternalArrayLength(LExternalArrayLength* instr) {
  Register result = ToRegister(instr->result());
  Register array = ToRegister(instr->InputAt(0));
  __ movl(result, FieldOperand(array, ExternalPixelArray::kLengthOffset));
}


void LCodeGen::DoValueOf(LValueOf* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());
  ASSERT(input.is(result));
  NearLabel done;
  // If the object is a smi return the object.
  __ JumpIfSmi(input, &done);

  // If the object is not a value type, return the object.
  __ CmpObjectType(input, JS_VALUE_TYPE, kScratchRegister);
  __ j(not_equal, &done);
  __ movq(result, FieldOperand(input, JSValue::kValueOffset));

  __ bind(&done);
}


void LCodeGen::DoBitNotI(LBitNotI* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->Equals(instr->result()));
  __ not_(ToRegister(input));
}


void LCodeGen::DoThrow(LThrow* instr) {
  __ push(ToRegister(instr->InputAt(0)));
  CallRuntime(Runtime::kThrow, 1, instr);

  if (FLAG_debug_code) {
    Comment("Unreachable code.");
    __ int3();
  }
}


void LCodeGen::DoAddI(LAddI* instr) {
  LOperand* left = instr->InputAt(0);
  LOperand* right = instr->InputAt(1);
  ASSERT(left->Equals(instr->result()));

  if (right->IsConstantOperand()) {
    __ addl(ToRegister(left),
            Immediate(ToInteger32(LConstantOperand::cast(right))));
  } else if (right->IsRegister()) {
    __ addl(ToRegister(left), ToRegister(right));
  } else {
    __ addl(ToRegister(left), ToOperand(right));
  }

  if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
    DeoptimizeIf(overflow, instr->environment());
  }
}


void LCodeGen::DoArithmeticD(LArithmeticD* instr) {
  XMMRegister left = ToDoubleRegister(instr->InputAt(0));
  XMMRegister right = ToDoubleRegister(instr->InputAt(1));
  XMMRegister result = ToDoubleRegister(instr->result());
  // All operations except MOD are computed in-place.
  ASSERT(instr->op() == Token::MOD || left.is(result));
  switch (instr->op()) {
    case Token::ADD:
      __ addsd(left, right);
      break;
    case Token::SUB:
       __ subsd(left, right);
       break;
    case Token::MUL:
      __ mulsd(left, right);
      break;
    case Token::DIV:
      __ divsd(left, right);
      break;
    case Token::MOD:
      __ PrepareCallCFunction(2);
      __ movsd(xmm0, left);
      ASSERT(right.is(xmm1));
      __ CallCFunction(
          ExternalReference::double_fp_operation(Token::MOD, isolate()), 2);
      __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
      __ movsd(result, xmm0);
      break;
    default:
      UNREACHABLE();
      break;
  }
}


void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
  ASSERT(ToRegister(instr->InputAt(0)).is(rdx));
  ASSERT(ToRegister(instr->InputAt(1)).is(rax));
  ASSERT(ToRegister(instr->result()).is(rax));

  TypeRecordingBinaryOpStub stub(instr->op(), NO_OVERWRITE);
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
}


int LCodeGen::GetNextEmittedBlock(int block) {
  for (int i = block + 1; i < graph()->blocks()->length(); ++i) {
    LLabel* label = chunk_->GetLabel(i);
    if (!label->HasReplacement()) return i;
  }
  return -1;
}


void LCodeGen::EmitBranch(int left_block, int right_block, Condition cc) {
  int next_block = GetNextEmittedBlock(current_block_);
  right_block = chunk_->LookupDestination(right_block);
  left_block = chunk_->LookupDestination(left_block);

  if (right_block == left_block) {
    EmitGoto(left_block);
  } else if (left_block == next_block) {
    __ j(NegateCondition(cc), chunk_->GetAssemblyLabel(right_block));
  } else if (right_block == next_block) {
    __ j(cc, chunk_->GetAssemblyLabel(left_block));
  } else {
    __ j(cc, chunk_->GetAssemblyLabel(left_block));
    if (cc != always) {
      __ jmp(chunk_->GetAssemblyLabel(right_block));
    }
  }
}


void LCodeGen::DoBranch(LBranch* instr) {
  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  Representation r = instr->hydrogen()->representation();
  if (r.IsInteger32()) {
    Register reg = ToRegister(instr->InputAt(0));
    __ testl(reg, reg);
    EmitBranch(true_block, false_block, not_zero);
  } else if (r.IsDouble()) {
    XMMRegister reg = ToDoubleRegister(instr->InputAt(0));
    __ xorpd(xmm0, xmm0);
    __ ucomisd(reg, xmm0);
    EmitBranch(true_block, false_block, not_equal);
  } else {
    ASSERT(r.IsTagged());
    Register reg = ToRegister(instr->InputAt(0));
    HType type = instr->hydrogen()->type();
    if (type.IsBoolean()) {
      __ CompareRoot(reg, Heap::kTrueValueRootIndex);
      EmitBranch(true_block, false_block, equal);
    } else if (type.IsSmi()) {
      __ SmiCompare(reg, Smi::FromInt(0));
      EmitBranch(true_block, false_block, not_equal);
    } else {
      Label* true_label = chunk_->GetAssemblyLabel(true_block);
      Label* false_label = chunk_->GetAssemblyLabel(false_block);

      __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
      __ j(equal, false_label);
      __ CompareRoot(reg, Heap::kTrueValueRootIndex);
      __ j(equal, true_label);
      __ CompareRoot(reg, Heap::kFalseValueRootIndex);
      __ j(equal, false_label);
      __ Cmp(reg, Smi::FromInt(0));
      __ j(equal, false_label);
      __ JumpIfSmi(reg, true_label);

      // Test for double values. Plus/minus zero and NaN are false.
      NearLabel call_stub;
      __ CompareRoot(FieldOperand(reg, HeapObject::kMapOffset),
                     Heap::kHeapNumberMapRootIndex);
      __ j(not_equal, &call_stub);

      // HeapNumber => false iff +0, -0, or NaN. These three cases set the
      // zero flag when compared to zero using ucomisd.
      __ xorpd(xmm0, xmm0);
      __ ucomisd(xmm0, FieldOperand(reg, HeapNumber::kValueOffset));
      __ j(zero, false_label);
      __ jmp(true_label);

      // The conversion stub doesn't cause garbage collections so it's
      // safe to not record a safepoint after the call.
      __ bind(&call_stub);
      ToBooleanStub stub;
      __ Pushad();
      __ push(reg);
      __ CallStub(&stub);
      __ testq(rax, rax);
      __ Popad();
      EmitBranch(true_block, false_block, not_zero);
    }
  }
}


void LCodeGen::EmitGoto(int block, LDeferredCode* deferred_stack_check) {
  block = chunk_->LookupDestination(block);
  int next_block = GetNextEmittedBlock(current_block_);
  if (block != next_block) {
    // Perform stack overflow check if this goto needs it before jumping.
    if (deferred_stack_check != NULL) {
      __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
      __ j(above_equal, chunk_->GetAssemblyLabel(block));
      __ jmp(deferred_stack_check->entry());
      deferred_stack_check->SetExit(chunk_->GetAssemblyLabel(block));
    } else {
      __ jmp(chunk_->GetAssemblyLabel(block));
    }
  }
}


void LCodeGen::DoDeferredStackCheck(LGoto* instr) {
  PushSafepointRegistersScope scope(this);
  CallRuntimeFromDeferred(Runtime::kStackGuard, 0, instr);
}


void LCodeGen::DoGoto(LGoto* instr) {
  class DeferredStackCheck: public LDeferredCode {
   public:
    DeferredStackCheck(LCodeGen* codegen, LGoto* instr)
        : LDeferredCode(codegen), instr_(instr) { }
    virtual void Generate() { codegen()->DoDeferredStackCheck(instr_); }
   private:
    LGoto* instr_;
  };

  DeferredStackCheck* deferred = NULL;
  if (instr->include_stack_check()) {
    deferred = new DeferredStackCheck(this, instr);
  }
  EmitGoto(instr->block_id(), deferred);
}


inline Condition LCodeGen::TokenToCondition(Token::Value op, bool is_unsigned) {
  Condition cond = no_condition;
  switch (op) {
    case Token::EQ:
    case Token::EQ_STRICT:
      cond = equal;
      break;
    case Token::LT:
      cond = is_unsigned ? below : less;
      break;
    case Token::GT:
      cond = is_unsigned ? above : greater;
      break;
    case Token::LTE:
      cond = is_unsigned ? below_equal : less_equal;
      break;
    case Token::GTE:
      cond = is_unsigned ? above_equal : greater_equal;
      break;
    case Token::IN:
    case Token::INSTANCEOF:
    default:
      UNREACHABLE();
  }
  return cond;
}


void LCodeGen::EmitCmpI(LOperand* left, LOperand* right) {
  if (right->IsConstantOperand()) {
    int32_t value = ToInteger32(LConstantOperand::cast(right));
    if (left->IsRegister()) {
      __ cmpl(ToRegister(left), Immediate(value));
    } else {
      __ cmpl(ToOperand(left), Immediate(value));
    }
  } else if (right->IsRegister()) {
    __ cmpl(ToRegister(left), ToRegister(right));
  } else {
    __ cmpl(ToRegister(left), ToOperand(right));
  }
}


void LCodeGen::DoCmpID(LCmpID* instr) {
  LOperand* left = instr->InputAt(0);
  LOperand* right = instr->InputAt(1);
  LOperand* result = instr->result();

  NearLabel unordered;
  if (instr->is_double()) {
    // Don't base result on EFLAGS when a NaN is involved. Instead
    // jump to the unordered case, which produces a false value.
    __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
    __ j(parity_even, &unordered);
  } else {
    EmitCmpI(left, right);
  }

  NearLabel done;
  Condition cc = TokenToCondition(instr->op(), instr->is_double());
  __ LoadRoot(ToRegister(result), Heap::kTrueValueRootIndex);
  __ j(cc, &done);

  __ bind(&unordered);
  __ LoadRoot(ToRegister(result), Heap::kFalseValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
  LOperand* left = instr->InputAt(0);
  LOperand* right = instr->InputAt(1);
  int false_block = chunk_->LookupDestination(instr->false_block_id());
  int true_block = chunk_->LookupDestination(instr->true_block_id());

  if (instr->is_double()) {
    // Don't base result on EFLAGS when a NaN is involved. Instead
    // jump to the false block.
    __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
    __ j(parity_even, chunk_->GetAssemblyLabel(false_block));
  } else {
    EmitCmpI(left, right);
  }

  Condition cc = TokenToCondition(instr->op(), instr->is_double());
  EmitBranch(true_block, false_block, cc);
}


void LCodeGen::DoCmpJSObjectEq(LCmpJSObjectEq* instr) {
  Register left = ToRegister(instr->InputAt(0));
  Register right = ToRegister(instr->InputAt(1));
  Register result = ToRegister(instr->result());

  NearLabel different, done;
  __ cmpq(left, right);
  __ j(not_equal, &different);
  __ LoadRoot(result, Heap::kTrueValueRootIndex);
  __ jmp(&done);
  __ bind(&different);
  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoCmpJSObjectEqAndBranch(LCmpJSObjectEqAndBranch* instr) {
  Register left = ToRegister(instr->InputAt(0));
  Register right = ToRegister(instr->InputAt(1));
  int false_block = chunk_->LookupDestination(instr->false_block_id());
  int true_block = chunk_->LookupDestination(instr->true_block_id());

  __ cmpq(left, right);
  EmitBranch(true_block, false_block, equal);
}


void LCodeGen::DoIsNull(LIsNull* instr) {
  Register reg = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());

  // If the expression is known to be a smi, then it's
  // definitely not null. Materialize false.
  // Consider adding other type and representation tests too.
  if (instr->hydrogen()->value()->type().IsSmi()) {
    __ LoadRoot(result, Heap::kFalseValueRootIndex);
    return;
  }

  __ CompareRoot(reg, Heap::kNullValueRootIndex);
  if (instr->is_strict()) {
    ASSERT(Heap::kTrueValueRootIndex >= 0);
    __ movl(result, Immediate(Heap::kTrueValueRootIndex));
    NearLabel load;
    __ j(equal, &load);
    __ Set(result, Heap::kFalseValueRootIndex);
    __ bind(&load);
    __ LoadRootIndexed(result, result, 0);
  } else {
    NearLabel true_value, false_value, done;
    __ j(equal, &true_value);
    __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
    __ j(equal, &true_value);
    __ JumpIfSmi(reg, &false_value);
    // Check for undetectable objects by looking in the bit field in
    // the map. The object has already been smi checked.
    Register scratch = result;
    __ movq(scratch, FieldOperand(reg, HeapObject::kMapOffset));
    __ testb(FieldOperand(scratch, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    __ j(not_zero, &true_value);
    __ bind(&false_value);
    __ LoadRoot(result, Heap::kFalseValueRootIndex);
    __ jmp(&done);
    __ bind(&true_value);
    __ LoadRoot(result, Heap::kTrueValueRootIndex);
    __ bind(&done);
  }
}


void LCodeGen::DoIsNullAndBranch(LIsNullAndBranch* instr) {
  Register reg = ToRegister(instr->InputAt(0));

  int false_block = chunk_->LookupDestination(instr->false_block_id());

  if (instr->hydrogen()->representation().IsSpecialization() ||
      instr->hydrogen()->type().IsSmi()) {
    // If the expression is known to untagged or smi, then it's definitely
    // not null, and it can't be a an undetectable object.
    // Jump directly to the false block.
    EmitGoto(false_block);
    return;
  }

  int true_block = chunk_->LookupDestination(instr->true_block_id());

  __ CompareRoot(reg, Heap::kNullValueRootIndex);
  if (instr->is_strict()) {
    EmitBranch(true_block, false_block, equal);
  } else {
    Label* true_label = chunk_->GetAssemblyLabel(true_block);
    Label* false_label = chunk_->GetAssemblyLabel(false_block);
    __ j(equal, true_label);
    __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
    __ j(equal, true_label);
    __ JumpIfSmi(reg, false_label);
    // Check for undetectable objects by looking in the bit field in
    // the map. The object has already been smi checked.
    Register scratch = ToRegister(instr->TempAt(0));
    __ movq(scratch, FieldOperand(reg, HeapObject::kMapOffset));
    __ testb(FieldOperand(scratch, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    EmitBranch(true_block, false_block, not_zero);
  }
}


Condition LCodeGen::EmitIsObject(Register input,
                                 Label* is_not_object,
                                 Label* is_object) {
  ASSERT(!input.is(kScratchRegister));

  __ JumpIfSmi(input, is_not_object);

  __ CompareRoot(input, Heap::kNullValueRootIndex);
  __ j(equal, is_object);

  __ movq(kScratchRegister, FieldOperand(input, HeapObject::kMapOffset));
  // Undetectable objects behave like undefined.
  __ testb(FieldOperand(kScratchRegister, Map::kBitFieldOffset),
           Immediate(1 << Map::kIsUndetectable));
  __ j(not_zero, is_not_object);

  __ movzxbl(kScratchRegister,
             FieldOperand(kScratchRegister, Map::kInstanceTypeOffset));
  __ cmpb(kScratchRegister, Immediate(FIRST_JS_OBJECT_TYPE));
  __ j(below, is_not_object);
  __ cmpb(kScratchRegister, Immediate(LAST_JS_OBJECT_TYPE));
  return below_equal;
}


void LCodeGen::DoIsObject(LIsObject* instr) {
  Register reg = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());
  Label is_false, is_true, done;

  Condition true_cond = EmitIsObject(reg, &is_false, &is_true);
  __ j(true_cond, &is_true);

  __ bind(&is_false);
  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ jmp(&done);

  __ bind(&is_true);
  __ LoadRoot(result, Heap::kTrueValueRootIndex);

  __ bind(&done);
}


void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
  Register reg = ToRegister(instr->InputAt(0));

  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());
  Label* true_label = chunk_->GetAssemblyLabel(true_block);
  Label* false_label = chunk_->GetAssemblyLabel(false_block);

  Condition true_cond = EmitIsObject(reg, false_label, true_label);

  EmitBranch(true_block, false_block, true_cond);
}


void LCodeGen::DoIsSmi(LIsSmi* instr) {
  LOperand* input_operand = instr->InputAt(0);
  Register result = ToRegister(instr->result());
  if (input_operand->IsRegister()) {
    Register input = ToRegister(input_operand);
    __ CheckSmiToIndicator(result, input);
  } else {
    Operand input = ToOperand(instr->InputAt(0));
    __ CheckSmiToIndicator(result, input);
  }
  // result is zero if input is a smi, and one otherwise.
  ASSERT(Heap::kFalseValueRootIndex == Heap::kTrueValueRootIndex + 1);
  __ LoadRootIndexed(result, result, Heap::kTrueValueRootIndex);
}


void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  Condition is_smi;
  if (instr->InputAt(0)->IsRegister()) {
    Register input = ToRegister(instr->InputAt(0));
    is_smi = masm()->CheckSmi(input);
  } else {
    Operand input = ToOperand(instr->InputAt(0));
    is_smi = masm()->CheckSmi(input);
  }
  EmitBranch(true_block, false_block, is_smi);
}


static InstanceType TestType(HHasInstanceType* instr) {
  InstanceType from = instr->from();
  InstanceType to = instr->to();
  if (from == FIRST_TYPE) return to;
  ASSERT(from == to || to == LAST_TYPE);
  return from;
}


static Condition BranchCondition(HHasInstanceType* instr) {
  InstanceType from = instr->from();
  InstanceType to = instr->to();
  if (from == to) return equal;
  if (to == LAST_TYPE) return above_equal;
  if (from == FIRST_TYPE) return below_equal;
  UNREACHABLE();
  return equal;
}


void LCodeGen::DoHasInstanceType(LHasInstanceType* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());

  ASSERT(instr->hydrogen()->value()->representation().IsTagged());
  __ testl(input, Immediate(kSmiTagMask));
  NearLabel done, is_false;
  __ j(zero, &is_false);
  __ CmpObjectType(input, TestType(instr->hydrogen()), result);
  __ j(NegateCondition(BranchCondition(instr->hydrogen())), &is_false);
  __ LoadRoot(result, Heap::kTrueValueRootIndex);
  __ jmp(&done);
  __ bind(&is_false);
  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
  Register input = ToRegister(instr->InputAt(0));

  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  Label* false_label = chunk_->GetAssemblyLabel(false_block);

  __ JumpIfSmi(input, false_label);

  __ CmpObjectType(input, TestType(instr->hydrogen()), kScratchRegister);
  EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
}


void LCodeGen::DoGetCachedArrayIndex(LGetCachedArrayIndex* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());

  if (FLAG_debug_code) {
    __ AbortIfNotString(input);
  }

  __ movl(result, FieldOperand(input, String::kHashFieldOffset));
  ASSERT(String::kHashShift >= kSmiTagSize);
  __ IndexFromHash(result, result);
}


void LCodeGen::DoHasCachedArrayIndex(LHasCachedArrayIndex* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());

  ASSERT(instr->hydrogen()->value()->representation().IsTagged());
  __ LoadRoot(result, Heap::kTrueValueRootIndex);
  __ testl(FieldOperand(input, String::kHashFieldOffset),
           Immediate(String::kContainsCachedArrayIndexMask));
  NearLabel done;
  __ j(zero, &done);
  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoHasCachedArrayIndexAndBranch(
    LHasCachedArrayIndexAndBranch* instr) {
  Register input = ToRegister(instr->InputAt(0));

  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  __ testl(FieldOperand(input, String::kHashFieldOffset),
           Immediate(String::kContainsCachedArrayIndexMask));
  EmitBranch(true_block, false_block, equal);
}


// Branches to a label or falls through with the answer in the z flag.
// Trashes the temp register and possibly input (if it and temp are aliased).
void LCodeGen::EmitClassOfTest(Label* is_true,
                               Label* is_false,
                               Handle<String> class_name,
                               Register input,
                               Register temp) {
  __ JumpIfSmi(input, is_false);
  __ CmpObjectType(input, FIRST_JS_OBJECT_TYPE, temp);
  __ j(below, is_false);

  // Map is now in temp.
  // Functions have class 'Function'.
  __ CmpInstanceType(temp, JS_FUNCTION_TYPE);
  if (class_name->IsEqualTo(CStrVector("Function"))) {
    __ j(equal, is_true);
  } else {
    __ j(equal, is_false);
  }

  // Check if the constructor in the map is a function.
  __ movq(temp, FieldOperand(temp, Map::kConstructorOffset));

  // As long as JS_FUNCTION_TYPE is the last instance type and it is
  // right after LAST_JS_OBJECT_TYPE, we can avoid checking for
  // LAST_JS_OBJECT_TYPE.
  ASSERT(LAST_TYPE == JS_FUNCTION_TYPE);
  ASSERT(JS_FUNCTION_TYPE == LAST_JS_OBJECT_TYPE + 1);

  // Objects with a non-function constructor have class 'Object'.
  __ CmpObjectType(temp, JS_FUNCTION_TYPE, kScratchRegister);
  if (class_name->IsEqualTo(CStrVector("Object"))) {
    __ j(not_equal, is_true);
  } else {
    __ j(not_equal, is_false);
  }

  // temp now contains the constructor function. Grab the
  // instance class name from there.
  __ movq(temp, FieldOperand(temp, JSFunction::kSharedFunctionInfoOffset));
  __ movq(temp, FieldOperand(temp,
                             SharedFunctionInfo::kInstanceClassNameOffset));
  // The class name we are testing against is a symbol because it's a literal.
  // The name in the constructor is a symbol because of the way the context is
  // booted.  This routine isn't expected to work for random API-created
  // classes and it doesn't have to because you can't access it with natives
  // syntax.  Since both sides are symbols it is sufficient to use an identity
  // comparison.
  ASSERT(class_name->IsSymbol());
  __ Cmp(temp, class_name);
  // End with the answer in the z flag.
}


void LCodeGen::DoClassOfTest(LClassOfTest* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());
  ASSERT(input.is(result));
  Register temp = ToRegister(instr->TempAt(0));
  Handle<String> class_name = instr->hydrogen()->class_name();
  NearLabel done;
  Label is_true, is_false;

  EmitClassOfTest(&is_true, &is_false, class_name, input, temp);

  __ j(not_equal, &is_false);

  __ bind(&is_true);
  __ LoadRoot(result, Heap::kTrueValueRootIndex);
  __ jmp(&done);

  __ bind(&is_false);
  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoClassOfTestAndBranch(LClassOfTestAndBranch* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register temp = ToRegister(instr->TempAt(0));
  Handle<String> class_name = instr->hydrogen()->class_name();

  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  Label* true_label = chunk_->GetAssemblyLabel(true_block);
  Label* false_label = chunk_->GetAssemblyLabel(false_block);

  EmitClassOfTest(true_label, false_label, class_name, input, temp);

  EmitBranch(true_block, false_block, equal);
}


void LCodeGen::DoCmpMapAndBranch(LCmpMapAndBranch* instr) {
  Register reg = ToRegister(instr->InputAt(0));
  int true_block = instr->true_block_id();
  int false_block = instr->false_block_id();

  __ Cmp(FieldOperand(reg, HeapObject::kMapOffset), instr->map());
  EmitBranch(true_block, false_block, equal);
}


void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
  InstanceofStub stub(InstanceofStub::kNoFlags);
  __ push(ToRegister(instr->InputAt(0)));
  __ push(ToRegister(instr->InputAt(1)));
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  NearLabel true_value, done;
  __ testq(rax, rax);
  __ j(zero, &true_value);
  __ LoadRoot(ToRegister(instr->result()), Heap::kFalseValueRootIndex);
  __ jmp(&done);
  __ bind(&true_value);
  __ LoadRoot(ToRegister(instr->result()), Heap::kTrueValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoInstanceOfAndBranch(LInstanceOfAndBranch* instr) {
  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  InstanceofStub stub(InstanceofStub::kNoFlags);
  __ push(ToRegister(instr->InputAt(0)));
  __ push(ToRegister(instr->InputAt(1)));
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  __ testq(rax, rax);
  EmitBranch(true_block, false_block, zero);
}


void LCodeGen::DoInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr) {
  class DeferredInstanceOfKnownGlobal: public LDeferredCode {
   public:
    DeferredInstanceOfKnownGlobal(LCodeGen* codegen,
                                  LInstanceOfKnownGlobal* instr)
        : LDeferredCode(codegen), instr_(instr) { }
    virtual void Generate() {
      codegen()->DoDeferredLInstanceOfKnownGlobal(instr_, &map_check_);
    }

    Label* map_check() { return &map_check_; }

   private:
    LInstanceOfKnownGlobal* instr_;
    Label map_check_;
  };


  DeferredInstanceOfKnownGlobal* deferred;
  deferred = new DeferredInstanceOfKnownGlobal(this, instr);

  Label done, false_result;
  Register object = ToRegister(instr->InputAt(0));

  // A Smi is not an instance of anything.
  __ JumpIfSmi(object, &false_result);

  // This is the inlined call site instanceof cache. The two occurences of the
  // hole value will be patched to the last map/result pair generated by the
  // instanceof stub.
  NearLabel cache_miss;
  // Use a temp register to avoid memory operands with variable lengths.
  Register map = ToRegister(instr->TempAt(0));
  __ movq(map, FieldOperand(object, HeapObject::kMapOffset));
  __ bind(deferred->map_check());  // Label for calculating code patching.
  __ movq(kScratchRegister, factory()->the_hole_value(),
          RelocInfo::EMBEDDED_OBJECT);
  __ cmpq(map, kScratchRegister);  // Patched to cached map.
  __ j(not_equal, &cache_miss);
  // Patched to load either true or false.
  __ LoadRoot(ToRegister(instr->result()), Heap::kTheHoleValueRootIndex);
#ifdef DEBUG
  // Check that the code size between patch label and patch sites is invariant.
  Label end_of_patched_code;
  __ bind(&end_of_patched_code);
  ASSERT(true);
#endif
  __ jmp(&done);

  // The inlined call site cache did not match. Check for null and string
  // before calling the deferred code.
  __ bind(&cache_miss);  // Null is not an instance of anything.
  __ CompareRoot(object, Heap::kNullValueRootIndex);
  __ j(equal, &false_result);

  // String values are not instances of anything.
  __ JumpIfNotString(object, kScratchRegister, deferred->entry());

  __ bind(&false_result);
  __ LoadRoot(ToRegister(instr->result()), Heap::kFalseValueRootIndex);

  __ bind(deferred->exit());
  __ bind(&done);
}


void LCodeGen::DoDeferredLInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
                                                Label* map_check) {
  {
    PushSafepointRegistersScope scope(this);
    InstanceofStub::Flags flags = static_cast<InstanceofStub::Flags>(
        InstanceofStub::kNoFlags | InstanceofStub::kCallSiteInlineCheck);
    InstanceofStub stub(flags);

    __ push(ToRegister(instr->InputAt(0)));
    __ Push(instr->function());

    Register temp = ToRegister(instr->TempAt(0));
    static const int kAdditionalDelta = 10;
    int delta =
        masm_->SizeOfCodeGeneratedSince(map_check) + kAdditionalDelta;
    ASSERT(delta >= 0);
    __ push_imm32(delta);

    // We are pushing three values on the stack but recording a
    // safepoint with two arguments because stub is going to
    // remove the third argument from the stack before jumping
    // to instanceof builtin on the slow path.
    CallCodeGeneric(stub.GetCode(),
                    RelocInfo::CODE_TARGET,
                    instr,
                    RECORD_SAFEPOINT_WITH_REGISTERS,
                    2);
    ASSERT(delta == masm_->SizeOfCodeGeneratedSince(map_check));
    // Move result to a register that survives the end of the
    // PushSafepointRegisterScope.
    __ movq(kScratchRegister, rax);
  }
  __ testq(kScratchRegister, kScratchRegister);
  Label load_false;
  Label done;
  __ j(not_zero, &load_false);
  __ LoadRoot(rax, Heap::kTrueValueRootIndex);
  __ jmp(&done);
  __ bind(&load_false);
  __ LoadRoot(rax, Heap::kFalseValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoCmpT(LCmpT* instr) {
  Token::Value op = instr->op();

  Handle<Code> ic = CompareIC::GetUninitialized(op);
  CallCode(ic, RelocInfo::CODE_TARGET, instr);

  Condition condition = TokenToCondition(op, false);
  if (op == Token::GT || op == Token::LTE) {
    condition = ReverseCondition(condition);
  }
  NearLabel true_value, done;
  __ testq(rax, rax);
  __ j(condition, &true_value);
  __ LoadRoot(ToRegister(instr->result()), Heap::kFalseValueRootIndex);
  __ jmp(&done);
  __ bind(&true_value);
  __ LoadRoot(ToRegister(instr->result()), Heap::kTrueValueRootIndex);
  __ bind(&done);
}


void LCodeGen::DoCmpTAndBranch(LCmpTAndBranch* instr) {
  Token::Value op = instr->op();
  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  Handle<Code> ic = CompareIC::GetUninitialized(op);
  CallCode(ic, RelocInfo::CODE_TARGET, instr);

  // The compare stub expects compare condition and the input operands
  // reversed for GT and LTE.
  Condition condition = TokenToCondition(op, false);
  if (op == Token::GT || op == Token::LTE) {
    condition = ReverseCondition(condition);
  }
  __ testq(rax, rax);
  EmitBranch(true_block, false_block, condition);
}


void LCodeGen::DoReturn(LReturn* instr) {
  if (FLAG_trace) {
    // Preserve the return value on the stack and rely on the runtime
    // call to return the value in the same register.
    __ push(rax);
    __ CallRuntime(Runtime::kTraceExit, 1);
  }
  __ movq(rsp, rbp);
  __ pop(rbp);
  __ Ret((ParameterCount() + 1) * kPointerSize, rcx);
}


void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
  Register result = ToRegister(instr->result());
  if (result.is(rax)) {
    __ load_rax(instr->hydrogen()->cell().location(),
                RelocInfo::GLOBAL_PROPERTY_CELL);
  } else {
    __ movq(result, instr->hydrogen()->cell(), RelocInfo::GLOBAL_PROPERTY_CELL);
    __ movq(result, Operand(result, 0));
  }
  if (instr->hydrogen()->check_hole_value()) {
    __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
    DeoptimizeIf(equal, instr->environment());
  }
}


void LCodeGen::DoLoadGlobalGeneric(LLoadGlobalGeneric* instr) {
  ASSERT(ToRegister(instr->global_object()).is(rax));
  ASSERT(ToRegister(instr->result()).is(rax));

  __ Move(rcx, instr->name());
  RelocInfo::Mode mode = instr->for_typeof() ? RelocInfo::CODE_TARGET :
                                               RelocInfo::CODE_TARGET_CONTEXT;
  Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
  CallCode(ic, mode, instr);
}


void LCodeGen::DoStoreGlobalCell(LStoreGlobalCell* instr) {
  Register value = ToRegister(instr->InputAt(0));
  Register temp = ToRegister(instr->TempAt(0));
  ASSERT(!value.is(temp));
  bool check_hole = instr->hydrogen()->check_hole_value();
  if (!check_hole && value.is(rax)) {
    __ store_rax(instr->hydrogen()->cell().location(),
                 RelocInfo::GLOBAL_PROPERTY_CELL);
    return;
  }
  // If the cell we are storing to contains the hole it could have
  // been deleted from the property dictionary. In that case, we need
  // to update the property details in the property dictionary to mark
  // it as no longer deleted. We deoptimize in that case.
  __ movq(temp, instr->hydrogen()->cell(), RelocInfo::GLOBAL_PROPERTY_CELL);
  if (check_hole) {
    __ CompareRoot(Operand(temp, 0), Heap::kTheHoleValueRootIndex);
    DeoptimizeIf(equal, instr->environment());
  }
  __ movq(Operand(temp, 0), value);
}


void LCodeGen::DoStoreGlobalGeneric(LStoreGlobalGeneric* instr) {
  ASSERT(ToRegister(instr->global_object()).is(rdx));
  ASSERT(ToRegister(instr->value()).is(rax));

  __ Move(rcx, instr->name());
  Handle<Code> ic = instr->strict_mode()
      ? isolate()->builtins()->StoreIC_Initialize_Strict()
      : isolate()->builtins()->StoreIC_Initialize();
  CallCode(ic, RelocInfo::CODE_TARGET_CONTEXT, instr);
}


void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
  Register context = ToRegister(instr->context());
  Register result = ToRegister(instr->result());
  __ movq(result, ContextOperand(context, instr->slot_index()));
}


void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
  Register context = ToRegister(instr->context());
  Register value = ToRegister(instr->value());
  __ movq(ContextOperand(context, instr->slot_index()), value);
  if (instr->needs_write_barrier()) {
    int offset = Context::SlotOffset(instr->slot_index());
    Register scratch = ToRegister(instr->TempAt(0));
    __ RecordWrite(context, offset, value, scratch);
  }
}


void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
  Register object = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());
  if (instr->hydrogen()->is_in_object()) {
    __ movq(result, FieldOperand(object, instr->hydrogen()->offset()));
  } else {
    __ movq(result, FieldOperand(object, JSObject::kPropertiesOffset));
    __ movq(result, FieldOperand(result, instr->hydrogen()->offset()));
  }
}


void LCodeGen::EmitLoadField(Register result,
                             Register object,
                             Handle<Map> type,
                             Handle<String> name) {
  LookupResult lookup;
  type->LookupInDescriptors(NULL, *name, &lookup);
  ASSERT(lookup.IsProperty() && lookup.type() == FIELD);
  int index = lookup.GetLocalFieldIndexFromMap(*type);
  int offset = index * kPointerSize;
  if (index < 0) {
    // Negative property indices are in-object properties, indexed
    // from the end of the fixed part of the object.
    __ movq(result, FieldOperand(object, offset + type->instance_size()));
  } else {
    // Non-negative property indices are in the properties array.
    __ movq(result, FieldOperand(object, JSObject::kPropertiesOffset));
    __ movq(result, FieldOperand(result, offset + FixedArray::kHeaderSize));
  }
}


void LCodeGen::DoLoadNamedFieldPolymorphic(LLoadNamedFieldPolymorphic* instr) {
  Register object = ToRegister(instr->object());
  Register result = ToRegister(instr->result());

  int map_count = instr->hydrogen()->types()->length();
  Handle<String> name = instr->hydrogen()->name();

  if (map_count == 0) {
    ASSERT(instr->hydrogen()->need_generic());
    __ Move(rcx, instr->hydrogen()->name());
    Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
    CallCode(ic, RelocInfo::CODE_TARGET, instr);
  } else {
    NearLabel done;
    for (int i = 0; i < map_count - 1; ++i) {
      Handle<Map> map = instr->hydrogen()->types()->at(i);
      NearLabel next;
      __ Cmp(FieldOperand(object, HeapObject::kMapOffset), map);
      __ j(not_equal, &next);
      EmitLoadField(result, object, map, name);
      __ jmp(&done);
      __ bind(&next);
    }
    Handle<Map> map = instr->hydrogen()->types()->last();
    __ Cmp(FieldOperand(object, HeapObject::kMapOffset), map);
    if (instr->hydrogen()->need_generic()) {
      NearLabel generic;
      __ j(not_equal, &generic);
      EmitLoadField(result, object, map, name);
      __ jmp(&done);
      __ bind(&generic);
      __ Move(rcx, instr->hydrogen()->name());
      Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
      CallCode(ic, RelocInfo::CODE_TARGET, instr);
    } else {
      DeoptimizeIf(not_equal, instr->environment());
      EmitLoadField(result, object, map, name);
    }
    __ bind(&done);
  }
}


void LCodeGen::DoLoadNamedGeneric(LLoadNamedGeneric* instr) {
  ASSERT(ToRegister(instr->object()).is(rax));
  ASSERT(ToRegister(instr->result()).is(rax));

  __ Move(rcx, instr->name());
  Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
  CallCode(ic, RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoLoadFunctionPrototype(LLoadFunctionPrototype* instr) {
  Register function = ToRegister(instr->function());
  Register result = ToRegister(instr->result());

  // Check that the function really is a function.
  __ CmpObjectType(function, JS_FUNCTION_TYPE, result);
  DeoptimizeIf(not_equal, instr->environment());

  // Check whether the function has an instance prototype.
  NearLabel non_instance;
  __ testb(FieldOperand(result, Map::kBitFieldOffset),
           Immediate(1 << Map::kHasNonInstancePrototype));
  __ j(not_zero, &non_instance);

  // Get the prototype or initial map from the function.
  __ movq(result,
         FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));

  // Check that the function has a prototype or an initial map.
  __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
  DeoptimizeIf(equal, instr->environment());

  // If the function does not have an initial map, we're done.
  NearLabel done;
  __ CmpObjectType(result, MAP_TYPE, kScratchRegister);
  __ j(not_equal, &done);

  // Get the prototype from the initial map.
  __ movq(result, FieldOperand(result, Map::kPrototypeOffset));
  __ jmp(&done);

  // Non-instance prototype: Fetch prototype from constructor field
  // in the function's map.
  __ bind(&non_instance);
  __ movq(result, FieldOperand(result, Map::kConstructorOffset));

  // All done.
  __ bind(&done);
}


void LCodeGen::DoLoadElements(LLoadElements* instr) {
  Register result = ToRegister(instr->result());
  Register input = ToRegister(instr->InputAt(0));
  __ movq(result, FieldOperand(input, JSObject::kElementsOffset));
  if (FLAG_debug_code) {
    NearLabel done;
    __ CompareRoot(FieldOperand(result, HeapObject::kMapOffset),
                   Heap::kFixedArrayMapRootIndex);
    __ j(equal, &done);
    __ CompareRoot(FieldOperand(result, HeapObject::kMapOffset),
                   Heap::kFixedCOWArrayMapRootIndex);
    __ j(equal, &done);
    Register temp((result.is(rax)) ? rbx : rax);
    __ push(temp);
    __ movq(temp, FieldOperand(result, HeapObject::kMapOffset));
    __ movzxbq(temp, FieldOperand(temp, Map::kInstanceTypeOffset));
    __ subq(temp, Immediate(FIRST_EXTERNAL_ARRAY_TYPE));
    __ cmpq(temp, Immediate(kExternalArrayTypeCount));
    __ pop(temp);
    __ Check(below, "Check for fast elements failed.");
    __ bind(&done);
  }
}


void LCodeGen::DoLoadExternalArrayPointer(
    LLoadExternalArrayPointer* instr) {
  Register result = ToRegister(instr->result());
  Register input = ToRegister(instr->InputAt(0));
  __ movq(result, FieldOperand(input,
                               ExternalPixelArray::kExternalPointerOffset));
}


void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
  Register arguments = ToRegister(instr->arguments());
  Register length = ToRegister(instr->length());
  Register result = ToRegister(instr->result());

  if (instr->index()->IsRegister()) {
    __ subl(length, ToRegister(instr->index()));
  } else {
    __ subl(length, ToOperand(instr->index()));
  }
  DeoptimizeIf(below_equal, instr->environment());

  // There are two words between the frame pointer and the last argument.
  // Subtracting from length accounts for one of them add one more.
  __ movq(result, Operand(arguments, length, times_pointer_size, kPointerSize));
}


void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
  Register elements = ToRegister(instr->elements());
  Register key = ToRegister(instr->key());
  Register result = ToRegister(instr->result());
  ASSERT(result.is(elements));

  // Load the result.
  __ movq(result, FieldOperand(elements,
                               key,
                               times_pointer_size,
                               FixedArray::kHeaderSize));

  // Check for the hole value.
  __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
  DeoptimizeIf(equal, instr->environment());
}


void LCodeGen::DoLoadKeyedSpecializedArrayElement(
    LLoadKeyedSpecializedArrayElement* instr) {
  Register external_pointer = ToRegister(instr->external_pointer());
  Register key = ToRegister(instr->key());
  ExternalArrayType array_type = instr->array_type();
  if (array_type == kExternalFloatArray) {
    XMMRegister result(ToDoubleRegister(instr->result()));
    __ movss(result, Operand(external_pointer, key, times_4, 0));
    __ cvtss2sd(result, result);
  } else {
    Register result(ToRegister(instr->result()));
    switch (array_type) {
      case kExternalByteArray:
        __ movsxbq(result, Operand(external_pointer, key, times_1, 0));
        break;
      case kExternalUnsignedByteArray:
      case kExternalPixelArray:
        __ movzxbq(result, Operand(external_pointer, key, times_1, 0));
        break;
      case kExternalShortArray:
        __ movsxwq(result, Operand(external_pointer, key, times_2, 0));
        break;
      case kExternalUnsignedShortArray:
        __ movzxwq(result, Operand(external_pointer, key, times_2, 0));
        break;
      case kExternalIntArray:
        __ movsxlq(result, Operand(external_pointer, key, times_4, 0));
        break;
      case kExternalUnsignedIntArray:
        __ movl(result, Operand(external_pointer, key, times_4, 0));
        __ testl(result, result);
        // TODO(danno): we could be more clever here, perhaps having a special
        // version of the stub that detects if the overflow case actually
        // happens, and generate code that returns a double rather than int.
        DeoptimizeIf(negative, instr->environment());
        break;
      case kExternalFloatArray:
        UNREACHABLE();
        break;
    }
  }
}


void LCodeGen::DoLoadKeyedGeneric(LLoadKeyedGeneric* instr) {
  ASSERT(ToRegister(instr->object()).is(rdx));
  ASSERT(ToRegister(instr->key()).is(rax));

  Handle<Code> ic = isolate()->builtins()->KeyedLoadIC_Initialize();
  CallCode(ic, RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoArgumentsElements(LArgumentsElements* instr) {
  Register result = ToRegister(instr->result());

  // Check for arguments adapter frame.
  NearLabel done, adapted;
  __ movq(result, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
  __ Cmp(Operand(result, StandardFrameConstants::kContextOffset),
         Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
  __ j(equal, &adapted);

  // No arguments adaptor frame.
  __ movq(result, rbp);
  __ jmp(&done);

  // Arguments adaptor frame present.
  __ bind(&adapted);
  __ movq(result, Operand(rbp, StandardFrameConstants::kCallerFPOffset));

  // Result is the frame pointer for the frame if not adapted and for the real
  // frame below the adaptor frame if adapted.
  __ bind(&done);
}


void LCodeGen::DoArgumentsLength(LArgumentsLength* instr) {
  Register result = ToRegister(instr->result());

  NearLabel done;

  // If no arguments adaptor frame the number of arguments is fixed.
  if (instr->InputAt(0)->IsRegister()) {
    __ cmpq(rbp, ToRegister(instr->InputAt(0)));
  } else {
    __ cmpq(rbp, ToOperand(instr->InputAt(0)));
  }
  __ movl(result, Immediate(scope()->num_parameters()));
  __ j(equal, &done);

  // Arguments adaptor frame present. Get argument length from there.
  __ movq(result, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
  __ SmiToInteger32(result,
                    Operand(result,
                            ArgumentsAdaptorFrameConstants::kLengthOffset));

  // Argument length is in result register.
  __ bind(&done);
}


void LCodeGen::DoApplyArguments(LApplyArguments* instr) {
  Register receiver = ToRegister(instr->receiver());
  Register function = ToRegister(instr->function());
  Register length = ToRegister(instr->length());
  Register elements = ToRegister(instr->elements());
  ASSERT(receiver.is(rax));  // Used for parameter count.
  ASSERT(function.is(rdi));  // Required by InvokeFunction.
  ASSERT(ToRegister(instr->result()).is(rax));

  // If the receiver is null or undefined, we have to pass the global object
  // as a receiver.
  NearLabel global_object, receiver_ok;
  __ CompareRoot(receiver, Heap::kNullValueRootIndex);
  __ j(equal, &global_object);
  __ CompareRoot(receiver, Heap::kUndefinedValueRootIndex);
  __ j(equal, &global_object);

  // The receiver should be a JS object.
  Condition is_smi = __ CheckSmi(receiver);
  DeoptimizeIf(is_smi, instr->environment());
  __ CmpObjectType(receiver, FIRST_JS_OBJECT_TYPE, kScratchRegister);
  DeoptimizeIf(below, instr->environment());
  __ jmp(&receiver_ok);

  __ bind(&global_object);
  // TODO(kmillikin): We have a hydrogen value for the global object.  See
  // if it's better to use it than to explicitly fetch it from the context
  // here.
  __ movq(receiver, Operand(rbp, StandardFrameConstants::kContextOffset));
  __ movq(receiver, ContextOperand(receiver, Context::GLOBAL_INDEX));
  __ bind(&receiver_ok);

  // Copy the arguments to this function possibly from the
  // adaptor frame below it.
  const uint32_t kArgumentsLimit = 1 * KB;
  __ cmpq(length, Immediate(kArgumentsLimit));
  DeoptimizeIf(above, instr->environment());

  __ push(receiver);
  __ movq(receiver, length);

  // Loop through the arguments pushing them onto the execution
  // stack.
  NearLabel invoke, loop;
  // length is a small non-negative integer, due to the test above.
  __ testl(length, length);
  __ j(zero, &invoke);
  __ bind(&loop);
  __ push(Operand(elements, length, times_pointer_size, 1 * kPointerSize));
  __ decl(length);
  __ j(not_zero, &loop);

  // Invoke the function.
  __ bind(&invoke);
  ASSERT(instr->HasPointerMap() && instr->HasDeoptimizationEnvironment());
  LPointerMap* pointers = instr->pointer_map();
  LEnvironment* env = instr->deoptimization_environment();
  RecordPosition(pointers->position());
  RegisterEnvironmentForDeoptimization(env);
  SafepointGenerator safepoint_generator(this,
                                         pointers,
                                         env->deoptimization_index());
  v8::internal::ParameterCount actual(rax);
  __ InvokeFunction(function, actual, CALL_FUNCTION, &safepoint_generator);
}


void LCodeGen::DoPushArgument(LPushArgument* instr) {
  LOperand* argument = instr->InputAt(0);
  if (argument->IsConstantOperand()) {
    EmitPushConstantOperand(argument);
  } else if (argument->IsRegister()) {
    __ push(ToRegister(argument));
  } else {
    ASSERT(!argument->IsDoubleRegister());
    __ push(ToOperand(argument));
  }
}


void LCodeGen::DoContext(LContext* instr) {
  Register result = ToRegister(instr->result());
  __ movq(result, Operand(rbp, StandardFrameConstants::kContextOffset));
}


void LCodeGen::DoOuterContext(LOuterContext* instr) {
  Register context = ToRegister(instr->context());
  Register result = ToRegister(instr->result());
  __ movq(result,
          Operand(context, Context::SlotOffset(Context::CLOSURE_INDEX)));
  __ movq(result, FieldOperand(result, JSFunction::kContextOffset));
}


void LCodeGen::DoGlobalObject(LGlobalObject* instr) {
  Register result = ToRegister(instr->result());
  __ movq(result, GlobalObjectOperand());
}


void LCodeGen::DoGlobalReceiver(LGlobalReceiver* instr) {
  Register global = ToRegister(instr->global());
  Register result = ToRegister(instr->result());
  __ movq(result, FieldOperand(global, GlobalObject::kGlobalReceiverOffset));
}


void LCodeGen::CallKnownFunction(Handle<JSFunction> function,
                                 int arity,
                                 LInstruction* instr) {
  // Change context if needed.
  bool change_context =
      (info()->closure()->context() != function->context()) ||
      scope()->contains_with() ||
      (scope()->num_heap_slots() > 0);
  if (change_context) {
    __ movq(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
  }

  // Set rax to arguments count if adaption is not needed. Assumes that rax
  // is available to write to at this point.
  if (!function->NeedsArgumentsAdaption()) {
    __ Set(rax, arity);
  }

  LPointerMap* pointers = instr->pointer_map();
  RecordPosition(pointers->position());

  // Invoke function.
  if (*function == *info()->closure()) {
    __ CallSelf();
  } else {
    __ call(FieldOperand(rdi, JSFunction::kCodeEntryOffset));
  }

  // Setup deoptimization.
  RegisterLazyDeoptimization(instr, RECORD_SIMPLE_SAFEPOINT, 0);

  // Restore context.
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
}


void LCodeGen::DoCallConstantFunction(LCallConstantFunction* instr) {
  ASSERT(ToRegister(instr->result()).is(rax));
  __ Move(rdi, instr->function());
  CallKnownFunction(instr->function(), instr->arity(), instr);
}


void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LUnaryMathOperation* instr) {
  Register input_reg = ToRegister(instr->InputAt(0));
  __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                 Heap::kHeapNumberMapRootIndex);
  DeoptimizeIf(not_equal, instr->environment());

  Label done;
  Register tmp = input_reg.is(rax) ? rcx : rax;
  Register tmp2 = tmp.is(rcx) ? rdx : input_reg.is(rcx) ? rdx : rcx;

  // Preserve the value of all registers.
  PushSafepointRegistersScope scope(this);

  Label negative;
  __ movl(tmp, FieldOperand(input_reg, HeapNumber::kExponentOffset));
  // Check the sign of the argument. If the argument is positive, just
  // return it. We do not need to patch the stack since |input| and
  // |result| are the same register and |input| will be restored
  // unchanged by popping safepoint registers.
  __ testl(tmp, Immediate(HeapNumber::kSignMask));
  __ j(not_zero, &negative);
  __ jmp(&done);

  __ bind(&negative);

  Label allocated, slow;
  __ AllocateHeapNumber(tmp, tmp2, &slow);
  __ jmp(&allocated);

  // Slow case: Call the runtime system to do the number allocation.
  __ bind(&slow);

  CallRuntimeFromDeferred(Runtime::kAllocateHeapNumber, 0, instr);
  // Set the pointer to the new heap number in tmp.
  if (!tmp.is(rax)) {
    __ movq(tmp, rax);
  }

  // Restore input_reg after call to runtime.
  __ LoadFromSafepointRegisterSlot(input_reg, input_reg);

  __ bind(&allocated);
  __ movq(tmp2, FieldOperand(input_reg, HeapNumber::kValueOffset));
  __ shl(tmp2, Immediate(1));
  __ shr(tmp2, Immediate(1));
  __ movq(FieldOperand(tmp, HeapNumber::kValueOffset), tmp2);
  __ StoreToSafepointRegisterSlot(input_reg, tmp);

  __ bind(&done);
}


void LCodeGen::EmitIntegerMathAbs(LUnaryMathOperation* instr) {
  Register input_reg = ToRegister(instr->InputAt(0));
  __ testl(input_reg, input_reg);
  Label is_positive;
  __ j(not_sign, &is_positive);
  __ negl(input_reg);  // Sets flags.
  DeoptimizeIf(negative, instr->environment());
  __ bind(&is_positive);
}


void LCodeGen::DoMathAbs(LUnaryMathOperation* instr) {
  // Class for deferred case.
  class DeferredMathAbsTaggedHeapNumber: public LDeferredCode {
   public:
    DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen,
                                    LUnaryMathOperation* instr)
        : LDeferredCode(codegen), instr_(instr) { }
    virtual void Generate() {
      codegen()->DoDeferredMathAbsTaggedHeapNumber(instr_);
    }
   private:
    LUnaryMathOperation* instr_;
  };

  ASSERT(instr->InputAt(0)->Equals(instr->result()));
  Representation r = instr->hydrogen()->value()->representation();

  if (r.IsDouble()) {
    XMMRegister scratch = xmm0;
    XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
    __ xorpd(scratch, scratch);
    __ subsd(scratch, input_reg);
    __ andpd(input_reg, scratch);
  } else if (r.IsInteger32()) {
    EmitIntegerMathAbs(instr);
  } else {  // Tagged case.
    DeferredMathAbsTaggedHeapNumber* deferred =
        new DeferredMathAbsTaggedHeapNumber(this, instr);
    Register input_reg = ToRegister(instr->InputAt(0));
    // Smi check.
    __ JumpIfNotSmi(input_reg, deferred->entry());
    __ SmiToInteger32(input_reg, input_reg);
    EmitIntegerMathAbs(instr);
    __ Integer32ToSmi(input_reg, input_reg);
    __ bind(deferred->exit());
  }
}


void LCodeGen::DoMathFloor(LUnaryMathOperation* instr) {
  XMMRegister xmm_scratch = xmm0;
  Register output_reg = ToRegister(instr->result());
  XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
  __ xorpd(xmm_scratch, xmm_scratch);  // Zero the register.
  __ ucomisd(input_reg, xmm_scratch);

  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
    DeoptimizeIf(below_equal, instr->environment());
  } else {
    DeoptimizeIf(below, instr->environment());
  }

  // Use truncating instruction (OK because input is positive).
  __ cvttsd2si(output_reg, input_reg);

  // Overflow is signalled with minint.
  __ cmpl(output_reg, Immediate(0x80000000));
  DeoptimizeIf(equal, instr->environment());
}


void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
  const XMMRegister xmm_scratch = xmm0;
  Register output_reg = ToRegister(instr->result());
  XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));

  // xmm_scratch = 0.5
  __ movq(kScratchRegister, V8_INT64_C(0x3FE0000000000000), RelocInfo::NONE);
  __ movq(xmm_scratch, kScratchRegister);

  // input = input + 0.5
  __ addsd(input_reg, xmm_scratch);

  // We need to return -0 for the input range [-0.5, 0[, otherwise
  // compute Math.floor(value + 0.5).
  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
    __ ucomisd(input_reg, xmm_scratch);
    DeoptimizeIf(below_equal, instr->environment());
  } else {
    // If we don't need to bailout on -0, we check only bailout
    // on negative inputs.
    __ xorpd(xmm_scratch, xmm_scratch);  // Zero the register.
    __ ucomisd(input_reg, xmm_scratch);
    DeoptimizeIf(below, instr->environment());
  }

  // Compute Math.floor(value + 0.5).
  // Use truncating instruction (OK because input is positive).
  __ cvttsd2si(output_reg, input_reg);

  // Overflow is signalled with minint.
  __ cmpl(output_reg, Immediate(0x80000000));
  DeoptimizeIf(equal, instr->environment());
}


void LCodeGen::DoMathSqrt(LUnaryMathOperation* instr) {
  XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
  ASSERT(ToDoubleRegister(instr->result()).is(input_reg));
  __ sqrtsd(input_reg, input_reg);
}


void LCodeGen::DoMathPowHalf(LUnaryMathOperation* instr) {
  XMMRegister xmm_scratch = xmm0;
  XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
  ASSERT(ToDoubleRegister(instr->result()).is(input_reg));
  __ xorpd(xmm_scratch, xmm_scratch);
  __ addsd(input_reg, xmm_scratch);  // Convert -0 to +0.
  __ sqrtsd(input_reg, input_reg);
}


void LCodeGen::DoPower(LPower* instr) {
  LOperand* left = instr->InputAt(0);
  XMMRegister left_reg = ToDoubleRegister(left);
  ASSERT(!left_reg.is(xmm1));
  LOperand* right = instr->InputAt(1);
  XMMRegister result_reg = ToDoubleRegister(instr->result());
  Representation exponent_type = instr->hydrogen()->right()->representation();
  if (exponent_type.IsDouble()) {
    __ PrepareCallCFunction(2);
    // Move arguments to correct registers
    __ movsd(xmm0, left_reg);
    ASSERT(ToDoubleRegister(right).is(xmm1));
    __ CallCFunction(
        ExternalReference::power_double_double_function(isolate()), 2);
  } else if (exponent_type.IsInteger32()) {
    __ PrepareCallCFunction(2);
    // Move arguments to correct registers: xmm0 and edi (not rdi).
    // On Windows, the registers are xmm0 and edx.
    __ movsd(xmm0, left_reg);
#ifdef _WIN64
    ASSERT(ToRegister(right).is(rdx));
#else
    ASSERT(ToRegister(right).is(rdi));
#endif
    __ CallCFunction(
        ExternalReference::power_double_int_function(isolate()), 2);
  } else {
    ASSERT(exponent_type.IsTagged());
    Register right_reg = ToRegister(right);

    Label non_smi, call;
    __ JumpIfNotSmi(right_reg, &non_smi);
    __ SmiToInteger32(right_reg, right_reg);
    __ cvtlsi2sd(xmm1, right_reg);
    __ jmp(&call);

    __ bind(&non_smi);
    __ CmpObjectType(right_reg, HEAP_NUMBER_TYPE , kScratchRegister);
    DeoptimizeIf(not_equal, instr->environment());
    __ movsd(xmm1, FieldOperand(right_reg, HeapNumber::kValueOffset));

    __ bind(&call);
    __ PrepareCallCFunction(2);
    // Move arguments to correct registers xmm0 and xmm1.
    __ movsd(xmm0, left_reg);
    // Right argument is already in xmm1.
    __ CallCFunction(
        ExternalReference::power_double_double_function(isolate()), 2);
  }
  // Return value is in xmm0.
  __ movsd(result_reg, xmm0);
  // Restore context register.
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
}


void LCodeGen::DoMathLog(LUnaryMathOperation* instr) {
  ASSERT(ToDoubleRegister(instr->result()).is(xmm1));
  TranscendentalCacheStub stub(TranscendentalCache::LOG,
                               TranscendentalCacheStub::UNTAGGED);
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoMathCos(LUnaryMathOperation* instr) {
  ASSERT(ToDoubleRegister(instr->result()).is(xmm1));
  TranscendentalCacheStub stub(TranscendentalCache::COS,
                               TranscendentalCacheStub::UNTAGGED);
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoMathSin(LUnaryMathOperation* instr) {
  ASSERT(ToDoubleRegister(instr->result()).is(xmm1));
  TranscendentalCacheStub stub(TranscendentalCache::SIN,
                               TranscendentalCacheStub::UNTAGGED);
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoUnaryMathOperation(LUnaryMathOperation* instr) {
  switch (instr->op()) {
    case kMathAbs:
      DoMathAbs(instr);
      break;
    case kMathFloor:
      DoMathFloor(instr);
      break;
    case kMathRound:
      DoMathRound(instr);
      break;
    case kMathSqrt:
      DoMathSqrt(instr);
      break;
    case kMathPowHalf:
      DoMathPowHalf(instr);
      break;
    case kMathCos:
      DoMathCos(instr);
      break;
    case kMathSin:
      DoMathSin(instr);
      break;
    case kMathLog:
      DoMathLog(instr);
      break;

    default:
      UNREACHABLE();
  }
}


void LCodeGen::DoCallKeyed(LCallKeyed* instr) {
  ASSERT(ToRegister(instr->key()).is(rcx));
  ASSERT(ToRegister(instr->result()).is(rax));

  int arity = instr->arity();
  Handle<Code> ic = isolate()->stub_cache()->ComputeKeyedCallInitialize(
    arity, NOT_IN_LOOP);
  CallCode(ic, RelocInfo::CODE_TARGET, instr);
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
}


void LCodeGen::DoCallNamed(LCallNamed* instr) {
  ASSERT(ToRegister(instr->result()).is(rax));

  int arity = instr->arity();
  Handle<Code> ic = isolate()->stub_cache()->ComputeCallInitialize(
      arity, NOT_IN_LOOP);
  __ Move(rcx, instr->name());
  CallCode(ic, RelocInfo::CODE_TARGET, instr);
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
}


void LCodeGen::DoCallFunction(LCallFunction* instr) {
  ASSERT(ToRegister(instr->result()).is(rax));

  int arity = instr->arity();
  CallFunctionStub stub(arity, NOT_IN_LOOP, RECEIVER_MIGHT_BE_VALUE);
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
  __ Drop(1);
}


void LCodeGen::DoCallGlobal(LCallGlobal* instr) {
  ASSERT(ToRegister(instr->result()).is(rax));
  int arity = instr->arity();
  Handle<Code> ic = isolate()->stub_cache()->ComputeCallInitialize(
      arity, NOT_IN_LOOP);
  __ Move(rcx, instr->name());
  CallCode(ic, RelocInfo::CODE_TARGET_CONTEXT, instr);
  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
}


void LCodeGen::DoCallKnownGlobal(LCallKnownGlobal* instr) {
  ASSERT(ToRegister(instr->result()).is(rax));
  __ Move(rdi, instr->target());
  CallKnownFunction(instr->target(), instr->arity(), instr);
}


void LCodeGen::DoCallNew(LCallNew* instr) {
  ASSERT(ToRegister(instr->InputAt(0)).is(rdi));
  ASSERT(ToRegister(instr->result()).is(rax));

  Handle<Code> builtin = isolate()->builtins()->JSConstructCall();
  __ Set(rax, instr->arity());
  CallCode(builtin, RelocInfo::CONSTRUCT_CALL, instr);
}


void LCodeGen::DoCallRuntime(LCallRuntime* instr) {
  CallRuntime(instr->function(), instr->arity(), instr);
}


void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
  Register object = ToRegister(instr->object());
  Register value = ToRegister(instr->value());
  int offset = instr->offset();

  if (!instr->transition().is_null()) {
    __ Move(FieldOperand(object, HeapObject::kMapOffset), instr->transition());
  }

  // Do the store.
  if (instr->is_in_object()) {
    __ movq(FieldOperand(object, offset), value);
    if (instr->needs_write_barrier()) {
      Register temp = ToRegister(instr->TempAt(0));
      // Update the write barrier for the object for in-object properties.
      __ RecordWrite(object, offset, value, temp);
    }
  } else {
    Register temp = ToRegister(instr->TempAt(0));
    __ movq(temp, FieldOperand(object, JSObject::kPropertiesOffset));
    __ movq(FieldOperand(temp, offset), value);
    if (instr->needs_write_barrier()) {
      // Update the write barrier for the properties array.
      // object is used as a scratch register.
      __ RecordWrite(temp, offset, value, object);
    }
  }
}


void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
  ASSERT(ToRegister(instr->object()).is(rdx));
  ASSERT(ToRegister(instr->value()).is(rax));

  __ Move(rcx, instr->hydrogen()->name());
  Handle<Code> ic = instr->strict_mode()
      ? isolate()->builtins()->StoreIC_Initialize_Strict()
      : isolate()->builtins()->StoreIC_Initialize();
  CallCode(ic, RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoStoreKeyedSpecializedArrayElement(
    LStoreKeyedSpecializedArrayElement* instr) {
  Register external_pointer = ToRegister(instr->external_pointer());
  Register key = ToRegister(instr->key());
  ExternalArrayType array_type = instr->array_type();
  if (array_type == kExternalFloatArray) {
    XMMRegister value(ToDoubleRegister(instr->value()));
    __ cvtsd2ss(value, value);
    __ movss(Operand(external_pointer, key, times_4, 0), value);
  } else {
    Register value(ToRegister(instr->value()));
    switch (array_type) {
      case kExternalPixelArray:
        {  // Clamp the value to [0..255].
          NearLabel done;
          __ testl(value, Immediate(0xFFFFFF00));
          __ j(zero, &done);
          __ setcc(negative, value);  // 1 if negative, 0 if positive.
          __ decb(value);  // 0 if negative, 255 if positive.
          __ bind(&done);
          __ movb(Operand(external_pointer, key, times_1, 0), value);
        }
        break;
      case kExternalByteArray:
      case kExternalUnsignedByteArray:
        __ movb(Operand(external_pointer, key, times_1, 0), value);
        break;
      case kExternalShortArray:
      case kExternalUnsignedShortArray:
        __ movw(Operand(external_pointer, key, times_2, 0), value);
        break;
      case kExternalIntArray:
      case kExternalUnsignedIntArray:
        __ movl(Operand(external_pointer, key, times_4, 0), value);
        break;
      case kExternalFloatArray:
        UNREACHABLE();
        break;
    }
  }
}


void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
  if (instr->length()->IsRegister()) {
    __ cmpq(ToRegister(instr->index()), ToRegister(instr->length()));
  } else {
    __ cmpq(ToRegister(instr->index()), ToOperand(instr->length()));
  }
  DeoptimizeIf(above_equal, instr->environment());
}


void LCodeGen::DoStoreKeyedFastElement(LStoreKeyedFastElement* instr) {
  Register value = ToRegister(instr->value());
  Register elements = ToRegister(instr->object());
  Register key = instr->key()->IsRegister() ? ToRegister(instr->key()) : no_reg;

  // Do the store.
  if (instr->key()->IsConstantOperand()) {
    ASSERT(!instr->hydrogen()->NeedsWriteBarrier());
    LConstantOperand* const_operand = LConstantOperand::cast(instr->key());
    int offset =
        ToInteger32(const_operand) * kPointerSize + FixedArray::kHeaderSize;
    __ movq(FieldOperand(elements, offset), value);
  } else {
    __ movq(FieldOperand(elements,
                         key,
                         times_pointer_size,
                         FixedArray::kHeaderSize),
            value);
  }

  if (instr->hydrogen()->NeedsWriteBarrier()) {
    // Compute address of modified element and store it into key register.
    __ lea(key, FieldOperand(elements,
                             key,
                             times_pointer_size,
                             FixedArray::kHeaderSize));
    __ RecordWrite(elements, key, value);
  }
}


void LCodeGen::DoStoreKeyedGeneric(LStoreKeyedGeneric* instr) {
  ASSERT(ToRegister(instr->object()).is(rdx));
  ASSERT(ToRegister(instr->key()).is(rcx));
  ASSERT(ToRegister(instr->value()).is(rax));

  Handle<Code> ic = instr->strict_mode()
      ? isolate()->builtins()->KeyedStoreIC_Initialize_Strict()
      : isolate()->builtins()->KeyedStoreIC_Initialize();
  CallCode(ic, RelocInfo::CODE_TARGET, instr);
}


void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
  class DeferredStringCharCodeAt: public LDeferredCode {
   public:
    DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
        : LDeferredCode(codegen), instr_(instr) { }
    virtual void Generate() { codegen()->DoDeferredStringCharCodeAt(instr_); }
   private:
    LStringCharCodeAt* instr_;
  };

  Register string = ToRegister(instr->string());
  Register index = no_reg;
  int const_index = -1;
  if (instr->index()->IsConstantOperand()) {
    const_index = ToInteger32(LConstantOperand::cast(instr->index()));
    STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue);
    if (!Smi::IsValid(const_index)) {
      // Guaranteed to be out of bounds because of the assert above.
      // So the bounds check that must dominate this instruction must
      // have deoptimized already.
      if (FLAG_debug_code) {
        __ Abort("StringCharCodeAt: out of bounds index.");
      }
      // No code needs to be generated.
      return;
    }
  } else {
    index = ToRegister(instr->index());
  }
  Register result = ToRegister(instr->result());

  DeferredStringCharCodeAt* deferred =
      new DeferredStringCharCodeAt(this, instr);

  NearLabel flat_string, ascii_string, done;

  // Fetch the instance type of the receiver into result register.
  __ movq(result, FieldOperand(string, HeapObject::kMapOffset));
  __ movzxbl(result, FieldOperand(result, Map::kInstanceTypeOffset));

  // We need special handling for non-sequential strings.
  STATIC_ASSERT(kSeqStringTag == 0);
  __ testb(result, Immediate(kStringRepresentationMask));
  __ j(zero, &flat_string);

  // Handle cons strings and go to deferred code for the rest.
  __ testb(result, Immediate(kIsConsStringMask));
  __ j(zero, deferred->entry());

  // ConsString.
  // Check whether the right hand side is the empty string (i.e. if
  // this is really a flat string in a cons string). If that is not
  // the case we would rather go to the runtime system now to flatten
  // the string.
  __ CompareRoot(FieldOperand(string, ConsString::kSecondOffset),
                 Heap::kEmptyStringRootIndex);
  __ j(not_equal, deferred->entry());
  // Get the first of the two strings and load its instance type.
  __ movq(string, FieldOperand(string, ConsString::kFirstOffset));
  __ movq(result, FieldOperand(string, HeapObject::kMapOffset));
  __ movzxbl(result, FieldOperand(result, Map::kInstanceTypeOffset));
  // If the first cons component is also non-flat, then go to runtime.
  STATIC_ASSERT(kSeqStringTag == 0);
  __ testb(result, Immediate(kStringRepresentationMask));
  __ j(not_zero, deferred->entry());

  // Check for ASCII or two-byte string.
  __ bind(&flat_string);
  STATIC_ASSERT(kAsciiStringTag != 0);
  __ testb(result, Immediate(kStringEncodingMask));
  __ j(not_zero, &ascii_string);

  // Two-byte string.
  // Load the two-byte character code into the result register.
  STATIC_ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
  if (instr->index()->IsConstantOperand()) {
    __ movzxwl(result,
               FieldOperand(string,
                            SeqTwoByteString::kHeaderSize +
                            (kUC16Size * const_index)));
  } else {
    __ movzxwl(result, FieldOperand(string,
                                    index,
                                    times_2,
                                    SeqTwoByteString::kHeaderSize));
  }
  __ jmp(&done);

  // ASCII string.
  // Load the byte into the result register.
  __ bind(&ascii_string);
  if (instr->index()->IsConstantOperand()) {
    __ movzxbl(result, FieldOperand(string,
                                    SeqAsciiString::kHeaderSize + const_index));
  } else {
    __ movzxbl(result, FieldOperand(string,
                                    index,
                                    times_1,
                                    SeqAsciiString::kHeaderSize));
  }
  __ bind(&done);
  __ bind(deferred->exit());
}


void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
  Register string = ToRegister(instr->string());
  Register result = ToRegister(instr->result());

  // TODO(3095996): Get rid of this. For now, we need to make the
  // result register contain a valid pointer because it is already
  // contained in the register pointer map.
  __ Set(result, 0);

  PushSafepointRegistersScope scope(this);
  __ push(string);
  // Push the index as a smi. This is safe because of the checks in
  // DoStringCharCodeAt above.
  STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue);
  if (instr->index()->IsConstantOperand()) {
    int const_index = ToInteger32(LConstantOperand::cast(instr->index()));
    __ Push(Smi::FromInt(const_index));
  } else {
    Register index = ToRegister(instr->index());
    __ Integer32ToSmi(index, index);
    __ push(index);
  }
  CallRuntimeFromDeferred(Runtime::kStringCharCodeAt, 2, instr);
  if (FLAG_debug_code) {
    __ AbortIfNotSmi(rax);
  }
  __ SmiToInteger32(rax, rax);
  __ StoreToSafepointRegisterSlot(result, rax);
}


void LCodeGen::DoStringCharFromCode(LStringCharFromCode* instr) {
  class DeferredStringCharFromCode: public LDeferredCode {
   public:
    DeferredStringCharFromCode(LCodeGen* codegen, LStringCharFromCode* instr)
        : LDeferredCode(codegen), instr_(instr) { }
    virtual void Generate() { codegen()->DoDeferredStringCharFromCode(instr_); }
   private:
    LStringCharFromCode* instr_;
  };

  DeferredStringCharFromCode* deferred =
      new DeferredStringCharFromCode(this, instr);

  ASSERT(instr->hydrogen()->value()->representation().IsInteger32());
  Register char_code = ToRegister(instr->char_code());
  Register result = ToRegister(instr->result());
  ASSERT(!char_code.is(result));

  __ cmpl(char_code, Immediate(String::kMaxAsciiCharCode));
  __ j(above, deferred->entry());
  __ LoadRoot(result, Heap::kSingleCharacterStringCacheRootIndex);
  __ movq(result, FieldOperand(result,
                               char_code, times_pointer_size,
                               FixedArray::kHeaderSize));
  __ CompareRoot(result, Heap::kUndefinedValueRootIndex);
  __ j(equal, deferred->entry());
  __ bind(deferred->exit());
}


void LCodeGen::DoDeferredStringCharFromCode(LStringCharFromCode* instr) {
  Register char_code = ToRegister(instr->char_code());
  Register result = ToRegister(instr->result());

  // TODO(3095996): Get rid of this. For now, we need to make the
  // result register contain a valid pointer because it is already
  // contained in the register pointer map.
  __ Set(result, 0);

  PushSafepointRegistersScope scope(this);
  __ Integer32ToSmi(char_code, char_code);
  __ push(char_code);
  CallRuntimeFromDeferred(Runtime::kCharFromCode, 1, instr);
  __ StoreToSafepointRegisterSlot(result, rax);
}


void LCodeGen::DoStringLength(LStringLength* instr) {
  Register string = ToRegister(instr->string());
  Register result = ToRegister(instr->result());
  __ movq(result, FieldOperand(string, String::kLengthOffset));
}


void LCodeGen::DoInteger32ToDouble(LInteger32ToDouble* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->IsRegister() || input->IsStackSlot());
  LOperand* output = instr->result();
  ASSERT(output->IsDoubleRegister());
  if (input->IsRegister()) {
    __ cvtlsi2sd(ToDoubleRegister(output), ToRegister(input));
  } else {
    __ cvtlsi2sd(ToDoubleRegister(output), ToOperand(input));
  }
}


void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->IsRegister() && input->Equals(instr->result()));
  Register reg = ToRegister(input);

  __ Integer32ToSmi(reg, reg);
}


void LCodeGen::DoNumberTagD(LNumberTagD* instr) {
  class DeferredNumberTagD: public LDeferredCode {
   public:
    DeferredNumberTagD(LCodeGen* codegen, LNumberTagD* instr)
        : LDeferredCode(codegen), instr_(instr) { }
    virtual void Generate() { codegen()->DoDeferredNumberTagD(instr_); }
   private:
    LNumberTagD* instr_;
  };

  XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
  Register reg = ToRegister(instr->result());
  Register tmp = ToRegister(instr->TempAt(0));

  DeferredNumberTagD* deferred = new DeferredNumberTagD(this, instr);
  if (FLAG_inline_new) {
    __ AllocateHeapNumber(reg, tmp, deferred->entry());
  } else {
    __ jmp(deferred->entry());
  }
  __ bind(deferred->exit());
  __ movsd(FieldOperand(reg, HeapNumber::kValueOffset), input_reg);
}


void LCodeGen::DoDeferredNumberTagD(LNumberTagD* instr) {
  // TODO(3095996): Get rid of this. For now, we need to make the
  // result register contain a valid pointer because it is already
  // contained in the register pointer map.
  Register reg = ToRegister(instr->result());
  __ Move(reg, Smi::FromInt(0));

  {
    PushSafepointRegistersScope scope(this);
    CallRuntimeFromDeferred(Runtime::kAllocateHeapNumber, 0, instr);
    // Ensure that value in rax survives popping registers.
    __ movq(kScratchRegister, rax);
  }
  __ movq(reg, kScratchRegister);
}


void LCodeGen::DoSmiTag(LSmiTag* instr) {
  ASSERT(instr->InputAt(0)->Equals(instr->result()));
  Register input = ToRegister(instr->InputAt(0));
  ASSERT(!instr->hydrogen_value()->CheckFlag(HValue::kCanOverflow));
  __ Integer32ToSmi(input, input);
}


void LCodeGen::DoSmiUntag(LSmiUntag* instr) {
  ASSERT(instr->InputAt(0)->Equals(instr->result()));
  Register input = ToRegister(instr->InputAt(0));
  if (instr->needs_check()) {
    Condition is_smi = __ CheckSmi(input);
    DeoptimizeIf(NegateCondition(is_smi), instr->environment());
  }
  __ SmiToInteger32(input, input);
}


void LCodeGen::EmitNumberUntagD(Register input_reg,
                                XMMRegister result_reg,
                                bool deoptimize_on_undefined,
                                LEnvironment* env) {
  NearLabel load_smi, done;

  // Smi check.
  __ JumpIfSmi(input_reg, &load_smi);

  // Heap number map check.
  __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                 Heap::kHeapNumberMapRootIndex);
  if (deoptimize_on_undefined) {
    DeoptimizeIf(not_equal, env);
  } else {
    NearLabel heap_number;
    __ j(equal, &heap_number);
    __ CompareRoot(input_reg, Heap::kUndefinedValueRootIndex);
    DeoptimizeIf(not_equal, env);

    // Convert undefined to NaN. Compute NaN as 0/0.
    __ xorpd(result_reg, result_reg);
    __ divsd(result_reg, result_reg);
    __ jmp(&done);

    __ bind(&heap_number);
  }
  // Heap number to XMM conversion.
  __ movsd(result_reg, FieldOperand(input_reg, HeapNumber::kValueOffset));
  __ jmp(&done);

  // Smi to XMM conversion
  __ bind(&load_smi);
  __ SmiToInteger32(kScratchRegister, input_reg);
  __ cvtlsi2sd(result_reg, kScratchRegister);
  __ bind(&done);
}


class DeferredTaggedToI: public LDeferredCode {
 public:
  DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
      : LDeferredCode(codegen), instr_(instr) { }
  virtual void Generate() { codegen()->DoDeferredTaggedToI(instr_); }
 private:
  LTaggedToI* instr_;
};


void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr) {
  NearLabel done, heap_number;
  Register input_reg = ToRegister(instr->InputAt(0));

  // Heap number map check.
  __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                 Heap::kHeapNumberMapRootIndex);

  if (instr->truncating()) {
    __ j(equal, &heap_number);
    // Check for undefined. Undefined is converted to zero for truncating
    // conversions.
    __ CompareRoot(input_reg, Heap::kUndefinedValueRootIndex);
    DeoptimizeIf(not_equal, instr->environment());
    __ Set(input_reg, 0);
    __ jmp(&done);

    __ bind(&heap_number);

    __ movsd(xmm0, FieldOperand(input_reg, HeapNumber::kValueOffset));
    __ cvttsd2siq(input_reg, xmm0);
    __ Set(kScratchRegister, V8_UINT64_C(0x8000000000000000));
    __ cmpq(input_reg, kScratchRegister);
    DeoptimizeIf(equal, instr->environment());
  } else {
    // Deoptimize if we don't have a heap number.
    DeoptimizeIf(not_equal, instr->environment());

    XMMRegister xmm_temp = ToDoubleRegister(instr->TempAt(0));
    __ movsd(xmm0, FieldOperand(input_reg, HeapNumber::kValueOffset));
    __ cvttsd2si(input_reg, xmm0);
    __ cvtlsi2sd(xmm_temp, input_reg);
    __ ucomisd(xmm0, xmm_temp);
    DeoptimizeIf(not_equal, instr->environment());
    DeoptimizeIf(parity_even, instr->environment());  // NaN.
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      __ testl(input_reg, input_reg);
      __ j(not_zero, &done);
      __ movmskpd(input_reg, xmm0);
      __ andl(input_reg, Immediate(1));
      DeoptimizeIf(not_zero, instr->environment());
    }
  }
  __ bind(&done);
}


void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->IsRegister());
  ASSERT(input->Equals(instr->result()));

  Register input_reg = ToRegister(input);
  DeferredTaggedToI* deferred = new DeferredTaggedToI(this, instr);
  __ JumpIfNotSmi(input_reg, deferred->entry());
  __ SmiToInteger32(input_reg, input_reg);
  __ bind(deferred->exit());
}


void LCodeGen::DoNumberUntagD(LNumberUntagD* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->IsRegister());
  LOperand* result = instr->result();
  ASSERT(result->IsDoubleRegister());

  Register input_reg = ToRegister(input);
  XMMRegister result_reg = ToDoubleRegister(result);

  EmitNumberUntagD(input_reg, result_reg,
                   instr->hydrogen()->deoptimize_on_undefined(),
                   instr->environment());
}


void LCodeGen::DoDoubleToI(LDoubleToI* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->IsDoubleRegister());
  LOperand* result = instr->result();
  ASSERT(result->IsRegister());

  XMMRegister input_reg = ToDoubleRegister(input);
  Register result_reg = ToRegister(result);

  if (instr->truncating()) {
    // Performs a truncating conversion of a floating point number as used by
    // the JS bitwise operations.
    __ cvttsd2siq(result_reg, input_reg);
    __ movq(kScratchRegister, V8_INT64_C(0x8000000000000000), RelocInfo::NONE);
    __ cmpq(result_reg, kScratchRegister);
      DeoptimizeIf(equal, instr->environment());
  } else {
    __ cvttsd2si(result_reg, input_reg);
    __ cvtlsi2sd(xmm0, result_reg);
    __ ucomisd(xmm0, input_reg);
    DeoptimizeIf(not_equal, instr->environment());
    DeoptimizeIf(parity_even, instr->environment());  // NaN.
    if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
      NearLabel done;
      // The integer converted back is equal to the original. We
      // only have to test if we got -0 as an input.
      __ testl(result_reg, result_reg);
      __ j(not_zero, &done);
      __ movmskpd(result_reg, input_reg);
      // Bit 0 contains the sign of the double in input_reg.
      // If input was positive, we are ok and return 0, otherwise
      // deoptimize.
      __ andl(result_reg, Immediate(1));
      DeoptimizeIf(not_zero, instr->environment());
      __ bind(&done);
    }
  }
}


void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
  LOperand* input = instr->InputAt(0);
  Condition cc = masm()->CheckSmi(ToRegister(input));
  DeoptimizeIf(NegateCondition(cc), instr->environment());
}


void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
  LOperand* input = instr->InputAt(0);
  Condition cc = masm()->CheckSmi(ToRegister(input));
  DeoptimizeIf(cc, instr->environment());
}


void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
  Register input = ToRegister(instr->InputAt(0));
  InstanceType first = instr->hydrogen()->first();
  InstanceType last = instr->hydrogen()->last();

  __ movq(kScratchRegister, FieldOperand(input, HeapObject::kMapOffset));

  // If there is only one type in the interval check for equality.
  if (first == last) {
    __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
            Immediate(static_cast<int8_t>(first)));
    DeoptimizeIf(not_equal, instr->environment());
  } else if (first == FIRST_STRING_TYPE && last == LAST_STRING_TYPE) {
    // String has a dedicated bit in instance type.
    __ testb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
             Immediate(kIsNotStringMask));
    DeoptimizeIf(not_zero, instr->environment());
  } else {
    __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
            Immediate(static_cast<int8_t>(first)));
    DeoptimizeIf(below, instr->environment());
    // Omit check for the last type.
    if (last != LAST_TYPE) {
      __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
              Immediate(static_cast<int8_t>(last)));
      DeoptimizeIf(above, instr->environment());
    }
  }
}


void LCodeGen::DoCheckFunction(LCheckFunction* instr) {
  ASSERT(instr->InputAt(0)->IsRegister());
  Register reg = ToRegister(instr->InputAt(0));
  __ Cmp(reg, instr->hydrogen()->target());
  DeoptimizeIf(not_equal, instr->environment());
}


void LCodeGen::DoCheckMap(LCheckMap* instr) {
  LOperand* input = instr->InputAt(0);
  ASSERT(input->IsRegister());
  Register reg = ToRegister(input);
  __ Cmp(FieldOperand(reg, HeapObject::kMapOffset),
         instr->hydrogen()->map());
  DeoptimizeIf(not_equal, instr->environment());
}


void LCodeGen::LoadHeapObject(Register result, Handle<HeapObject> object) {
  if (heap()->InNewSpace(*object)) {
    Handle<JSGlobalPropertyCell> cell =
        factory()->NewJSGlobalPropertyCell(object);
    __ movq(result, cell, RelocInfo::GLOBAL_PROPERTY_CELL);
    __ movq(result, Operand(result, 0));
  } else {
    __ Move(result, object);
  }
}


void LCodeGen::DoCheckPrototypeMaps(LCheckPrototypeMaps* instr) {
  Register reg = ToRegister(instr->TempAt(0));

  Handle<JSObject> holder = instr->holder();
  Handle<JSObject> current_prototype = instr->prototype();

  // Load prototype object.
  LoadHeapObject(reg, current_prototype);

  // Check prototype maps up to the holder.
  while (!current_prototype.is_identical_to(holder)) {
    __ Cmp(FieldOperand(reg, HeapObject::kMapOffset),
           Handle<Map>(current_prototype->map()));
    DeoptimizeIf(not_equal, instr->environment());
    current_prototype =
        Handle<JSObject>(JSObject::cast(current_prototype->GetPrototype()));
    // Load next prototype object.
    LoadHeapObject(reg, current_prototype);
  }

  // Check the holder map.
  __ Cmp(FieldOperand(reg, HeapObject::kMapOffset),
         Handle<Map>(current_prototype->map()));
  DeoptimizeIf(not_equal, instr->environment());
}


void LCodeGen::DoArrayLiteral(LArrayLiteral* instr) {
  // Setup the parameters to the stub/runtime call.
  __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
  __ push(FieldOperand(rax, JSFunction::kLiteralsOffset));
  __ Push(Smi::FromInt(instr->hydrogen()->literal_index()));
  __ Push(instr->hydrogen()->constant_elements());

  // Pick the right runtime function or stub to call.
  int length = instr->hydrogen()->length();
  if (instr->hydrogen()->IsCopyOnWrite()) {
    ASSERT(instr->hydrogen()->depth() == 1);
    FastCloneShallowArrayStub::Mode mode =
        FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS;
    FastCloneShallowArrayStub stub(mode, length);
    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  } else if (instr->hydrogen()->depth() > 1) {
    CallRuntime(Runtime::kCreateArrayLiteral, 3, instr);
  } else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
    CallRuntime(Runtime::kCreateArrayLiteralShallow, 3, instr);
  } else {
    FastCloneShallowArrayStub::Mode mode =
        FastCloneShallowArrayStub::CLONE_ELEMENTS;
    FastCloneShallowArrayStub stub(mode, length);
    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  }
}


void LCodeGen::DoObjectLiteral(LObjectLiteral* instr) {
  // Setup the parameters to the stub/runtime call.
  __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
  __ push(FieldOperand(rax, JSFunction::kLiteralsOffset));
  __ Push(Smi::FromInt(instr->hydrogen()->literal_index()));
  __ Push(instr->hydrogen()->constant_properties());
  __ Push(Smi::FromInt(instr->hydrogen()->fast_elements() ? 1 : 0));

  // Pick the right runtime function to call.
  if (instr->hydrogen()->depth() > 1) {
    CallRuntime(Runtime::kCreateObjectLiteral, 4, instr);
  } else {
    CallRuntime(Runtime::kCreateObjectLiteralShallow, 4, instr);
  }
}


void LCodeGen::DoToFastProperties(LToFastProperties* instr) {
  ASSERT(ToRegister(instr->InputAt(0)).is(rax));
  __ push(rax);
  CallRuntime(Runtime::kToFastProperties, 1, instr);
}


void LCodeGen::DoRegExpLiteral(LRegExpLiteral* instr) {
  NearLabel materialized;
  // Registers will be used as follows:
  // rdi = JS function.
  // rcx = literals array.
  // rbx = regexp literal.
  // rax = regexp literal clone.
  __ movq(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
  __ movq(rcx, FieldOperand(rdi, JSFunction::kLiteralsOffset));
  int literal_offset = FixedArray::kHeaderSize +
      instr->hydrogen()->literal_index() * kPointerSize;
  __ movq(rbx, FieldOperand(rcx, literal_offset));
  __ CompareRoot(rbx, Heap::kUndefinedValueRootIndex);
  __ j(not_equal, &materialized);

  // Create regexp literal using runtime function
  // Result will be in rax.
  __ push(rcx);
  __ Push(Smi::FromInt(instr->hydrogen()->literal_index()));
  __ Push(instr->hydrogen()->pattern());
  __ Push(instr->hydrogen()->flags());
  CallRuntime(Runtime::kMaterializeRegExpLiteral, 4, instr);
  __ movq(rbx, rax);

  __ bind(&materialized);
  int size = JSRegExp::kSize + JSRegExp::kInObjectFieldCount * kPointerSize;
  Label allocated, runtime_allocate;
  __ AllocateInNewSpace(size, rax, rcx, rdx, &runtime_allocate, TAG_OBJECT);
  __ jmp(&allocated);

  __ bind(&runtime_allocate);
  __ push(rbx);
  __ Push(Smi::FromInt(size));
  CallRuntime(Runtime::kAllocateInNewSpace, 1, instr);
  __ pop(rbx);

  __ bind(&allocated);
  // Copy the content into the newly allocated memory.
  // (Unroll copy loop once for better throughput).
  for (int i = 0; i < size - kPointerSize; i += 2 * kPointerSize) {
    __ movq(rdx, FieldOperand(rbx, i));
    __ movq(rcx, FieldOperand(rbx, i + kPointerSize));
    __ movq(FieldOperand(rax, i), rdx);
    __ movq(FieldOperand(rax, i + kPointerSize), rcx);
  }
  if ((size % (2 * kPointerSize)) != 0) {
    __ movq(rdx, FieldOperand(rbx, size - kPointerSize));
    __ movq(FieldOperand(rax, size - kPointerSize), rdx);
  }
}


void LCodeGen::DoFunctionLiteral(LFunctionLiteral* instr) {
  // Use the fast case closure allocation code that allocates in new
  // space for nested functions that don't need literals cloning.
  Handle<SharedFunctionInfo> shared_info = instr->shared_info();
  bool pretenure = instr->hydrogen()->pretenure();
  if (!pretenure && shared_info->num_literals() == 0) {
    FastNewClosureStub stub(
        shared_info->strict_mode() ? kStrictMode : kNonStrictMode);
    __ Push(shared_info);
    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  } else {
    __ push(rsi);
    __ Push(shared_info);
    __ PushRoot(pretenure ?
                Heap::kTrueValueRootIndex :
                Heap::kFalseValueRootIndex);
    CallRuntime(Runtime::kNewClosure, 3, instr);
  }
}


void LCodeGen::DoTypeof(LTypeof* instr) {
  LOperand* input = instr->InputAt(0);
  if (input->IsConstantOperand()) {
    __ Push(ToHandle(LConstantOperand::cast(input)));
  } else if (input->IsRegister()) {
    __ push(ToRegister(input));
  } else {
    ASSERT(input->IsStackSlot());
    __ push(ToOperand(input));
  }
  CallRuntime(Runtime::kTypeof, 1, instr);
}


void LCodeGen::DoTypeofIs(LTypeofIs* instr) {
  Register input = ToRegister(instr->InputAt(0));
  Register result = ToRegister(instr->result());
  Label true_label;
  Label false_label;
  NearLabel done;

  Condition final_branch_condition = EmitTypeofIs(&true_label,
                                                  &false_label,
                                                  input,
                                                  instr->type_literal());
  __ j(final_branch_condition, &true_label);
  __ bind(&false_label);
  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ jmp(&done);

  __ bind(&true_label);
  __ LoadRoot(result, Heap::kTrueValueRootIndex);

  __ bind(&done);
}


void LCodeGen::EmitPushConstantOperand(LOperand* operand) {
  ASSERT(operand->IsConstantOperand());
  LConstantOperand* const_op = LConstantOperand::cast(operand);
  Handle<Object> literal = chunk_->LookupLiteral(const_op);
  Representation r = chunk_->LookupLiteralRepresentation(const_op);
  if (r.IsInteger32()) {
    ASSERT(literal->IsNumber());
    __ push(Immediate(static_cast<int32_t>(literal->Number())));
  } else if (r.IsDouble()) {
    Abort("unsupported double immediate");
  } else {
    ASSERT(r.IsTagged());
    __ Push(literal);
  }
}


void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
  Register input = ToRegister(instr->InputAt(0));
  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());
  Label* true_label = chunk_->GetAssemblyLabel(true_block);
  Label* false_label = chunk_->GetAssemblyLabel(false_block);

  Condition final_branch_condition = EmitTypeofIs(true_label,
                                                  false_label,
                                                  input,
                                                  instr->type_literal());

  EmitBranch(true_block, false_block, final_branch_condition);
}


Condition LCodeGen::EmitTypeofIs(Label* true_label,
                                 Label* false_label,
                                 Register input,
                                 Handle<String> type_name) {
  Condition final_branch_condition = no_condition;
  if (type_name->Equals(heap()->number_symbol())) {
    __ JumpIfSmi(input, true_label);
    __ CompareRoot(FieldOperand(input, HeapObject::kMapOffset),
                   Heap::kHeapNumberMapRootIndex);

    final_branch_condition = equal;

  } else if (type_name->Equals(heap()->string_symbol())) {
    __ JumpIfSmi(input, false_label);
    __ CmpObjectType(input, FIRST_NONSTRING_TYPE, input);
    __ j(above_equal, false_label);
    __ testb(FieldOperand(input, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    final_branch_condition = zero;

  } else if (type_name->Equals(heap()->boolean_symbol())) {
    __ CompareRoot(input, Heap::kTrueValueRootIndex);
    __ j(equal, true_label);
    __ CompareRoot(input, Heap::kFalseValueRootIndex);
    final_branch_condition = equal;

  } else if (type_name->Equals(heap()->undefined_symbol())) {
    __ CompareRoot(input, Heap::kUndefinedValueRootIndex);
    __ j(equal, true_label);
    __ JumpIfSmi(input, false_label);
    // Check for undetectable objects => true.
    __ movq(input, FieldOperand(input, HeapObject::kMapOffset));
    __ testb(FieldOperand(input, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    final_branch_condition = not_zero;

  } else if (type_name->Equals(heap()->function_symbol())) {
    __ JumpIfSmi(input, false_label);
    __ CmpObjectType(input, FIRST_FUNCTION_CLASS_TYPE, input);
    final_branch_condition = above_equal;

  } else if (type_name->Equals(heap()->object_symbol())) {
    __ JumpIfSmi(input, false_label);
    __ CompareRoot(input, Heap::kNullValueRootIndex);
    __ j(equal, true_label);
    __ CmpObjectType(input, FIRST_JS_OBJECT_TYPE, input);
    __ j(below, false_label);
    __ CmpInstanceType(input, FIRST_FUNCTION_CLASS_TYPE);
    __ j(above_equal, false_label);
    // Check for undetectable objects => false.
    __ testb(FieldOperand(input, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsUndetectable));
    final_branch_condition = zero;

  } else {
    final_branch_condition = never;
    __ jmp(false_label);
  }

  return final_branch_condition;
}


void LCodeGen::DoIsConstructCall(LIsConstructCall* instr) {
  Register result = ToRegister(instr->result());
  NearLabel true_label;
  NearLabel false_label;
  NearLabel done;

  EmitIsConstructCall(result);
  __ j(equal, &true_label);

  __ LoadRoot(result, Heap::kFalseValueRootIndex);
  __ jmp(&done);

  __ bind(&true_label);
  __ LoadRoot(result, Heap::kTrueValueRootIndex);


  __ bind(&done);
}


void LCodeGen::DoIsConstructCallAndBranch(LIsConstructCallAndBranch* instr) {
  Register temp = ToRegister(instr->TempAt(0));
  int true_block = chunk_->LookupDestination(instr->true_block_id());
  int false_block = chunk_->LookupDestination(instr->false_block_id());

  EmitIsConstructCall(temp);
  EmitBranch(true_block, false_block, equal);
}


void LCodeGen::EmitIsConstructCall(Register temp) {
  // Get the frame pointer for the calling frame.
  __ movq(temp, Operand(rbp, StandardFrameConstants::kCallerFPOffset));

  // Skip the arguments adaptor frame if it exists.
  NearLabel check_frame_marker;
  __ Cmp(Operand(temp, StandardFrameConstants::kContextOffset),
         Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
  __ j(not_equal, &check_frame_marker);
  __ movq(temp, Operand(rax, StandardFrameConstants::kCallerFPOffset));

  // Check the marker in the calling frame.
  __ bind(&check_frame_marker);
  __ Cmp(Operand(temp, StandardFrameConstants::kMarkerOffset),
         Smi::FromInt(StackFrame::CONSTRUCT));
}


void LCodeGen::DoLazyBailout(LLazyBailout* instr) {
  // No code for lazy bailout instruction. Used to capture environment after a
  // call for populating the safepoint data with deoptimization data.
}


void LCodeGen::DoDeoptimize(LDeoptimize* instr) {
  DeoptimizeIf(no_condition, instr->environment());
}


void LCodeGen::DoDeleteProperty(LDeleteProperty* instr) {
  LOperand* obj = instr->object();
  LOperand* key = instr->key();
  // Push object.
  if (obj->IsRegister()) {
    __ push(ToRegister(obj));
  } else {
    __ push(ToOperand(obj));
  }
  // Push key.
  if (key->IsConstantOperand()) {
    EmitPushConstantOperand(key);
  } else if (key->IsRegister()) {
    __ push(ToRegister(key));
  } else {
    __ push(ToOperand(key));
  }
  ASSERT(instr->HasPointerMap() && instr->HasDeoptimizationEnvironment());
  LPointerMap* pointers = instr->pointer_map();
  LEnvironment* env = instr->deoptimization_environment();
  RecordPosition(pointers->position());
  RegisterEnvironmentForDeoptimization(env);
  // Create safepoint generator that will also ensure enough space in the
  // reloc info for patching in deoptimization (since this is invoking a
  // builtin)
  SafepointGenerator safepoint_generator(this,
                                         pointers,
                                         env->deoptimization_index());
  __ Push(Smi::FromInt(strict_mode_flag()));
  __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION, &safepoint_generator);
}


void LCodeGen::DoStackCheck(LStackCheck* instr) {
  // Perform stack overflow check.
  NearLabel done;
  __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
  __ j(above_equal, &done);

  StackCheckStub stub;
  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
  __ bind(&done);
}


void LCodeGen::DoOsrEntry(LOsrEntry* instr) {
  // This is a pseudo-instruction that ensures that the environment here is
  // properly registered for deoptimization and records the assembler's PC
  // offset.
  LEnvironment* environment = instr->environment();
  environment->SetSpilledRegisters(instr->SpilledRegisterArray(),
                                   instr->SpilledDoubleRegisterArray());

  // If the environment were already registered, we would have no way of
  // backpatching it with the spill slot operands.
  ASSERT(!environment->HasBeenRegistered());
  RegisterEnvironmentForDeoptimization(environment);
  ASSERT(osr_pc_offset_ == -1);
  osr_pc_offset_ = masm()->pc_offset();
}

#undef __

} }  // namespace v8::internal

#endif  // V8_TARGET_ARCH_X64