CSE2410 Fall 2014 Bounce

// Copyright 2012 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"

#include "lithium-allocator-inl.h"

#include "arm/lithium-arm.h"

#include "arm/lithium-codegen-arm.h"

#include "hydrogen-osr.h"

namespace v8 {

namespace internal {

#define DEFINE_COMPILE(type)                            \

  void L##type::CompileToNative(LCodeGen* generator) {  \

    generator->Do##type(this);                          \

  }

LITHIUM_CONCRETE_INSTRUCTION_LIST(DEFINE_COMPILE)

#undef DEFINE_COMPILE

#ifdef DEBUG

void LInstruction::VerifyCall() {

  // Call instructions can use only fixed registers as temporaries and

  // outputs because all registers are blocked by the calling convention.

  // Inputs operands must use a fixed register or use-at-start policy or

  // a non-register policy.

  ASSERT(Output() == NULL ||

         LUnallocated::cast(Output())->HasFixedPolicy() ||

         !LUnallocated::cast(Output())->HasRegisterPolicy());

  for (UseIterator it(this); !it.Done(); it.Advance()) {

    LUnallocated* operand = LUnallocated::cast(it.Current());

    ASSERT(operand->HasFixedPolicy() ||

           operand->IsUsedAtStart());

  }

  for (TempIterator it(this); !it.Done(); it.Advance()) {

    LUnallocated* operand = LUnallocated::cast(it.Current());

    ASSERT(operand->HasFixedPolicy() ||!operand->HasRegisterPolicy());

  }

}

#endif

void LInstruction::PrintTo(StringStream* stream) {

  stream->Add("%s ", this->Mnemonic());

  PrintOutputOperandTo(stream);

  PrintDataTo(stream);

  if (HasEnvironment()) {

    stream->Add(" ");

    environment()->PrintTo(stream);

  }

  if (HasPointerMap()) {

    stream->Add(" ");

    pointer_map()->PrintTo(stream);

  }

}

void LInstruction::PrintDataTo(StringStream* stream) {

  stream->Add("= ");

  for (int i = 0; i < InputCount(); i++) {

    if (i > 0) stream->Add(" ");

    if (InputAt(i) == NULL) {

      stream->Add("NULL");

    } else {

      InputAt(i)->PrintTo(stream);

    }

  }

}

void LInstruction::PrintOutputOperandTo(StringStream* stream) {

  if (HasResult()) result()->PrintTo(stream);

}

void LLabel::PrintDataTo(StringStream* stream) {

  LGap::PrintDataTo(stream);

  LLabel* rep = replacement();

  if (rep != NULL) {

    stream->Add(" Dead block replaced with B%d", rep->block_id());

  }

}

bool LGap::IsRedundant() const {

  for (int i = 0; i < 4; i++) {

    if (parallel_moves_[i] != NULL && !parallel_moves_[i]->IsRedundant()) {

      return false;

    }

  }

  return true;

}

void LGap::PrintDataTo(StringStream* stream) {

  for (int i = 0; i < 4; i++) {

    stream->Add("(");

    if (parallel_moves_[i] != NULL) {

      parallel_moves_[i]->PrintDataTo(stream);

    }

    stream->Add(") ");

  }

}

const char* LArithmeticD::Mnemonic() const {

  switch (op()) {

    case Token::ADD: return "add-d";

    case Token::SUB: return "sub-d";

    case Token::MUL: return "mul-d";

    case Token::DIV: return "div-d";

    case Token::MOD: return "mod-d";

    default:

      UNREACHABLE();

      return NULL;

  }

}

const char* LArithmeticT::Mnemonic() const {

  switch (op()) {

    case Token::ADD: return "add-t";

    case Token::SUB: return "sub-t";

    case Token::MUL: return "mul-t";

    case Token::MOD: return "mod-t";

    case Token::DIV: return "div-t";

    case Token::BIT_AND: return "bit-and-t";

    case Token::BIT_OR: return "bit-or-t";

    case Token::BIT_XOR: return "bit-xor-t";

    case Token::ROR: return "ror-t";

    case Token::SHL: return "shl-t";

    case Token::SAR: return "sar-t";

    case Token::SHR: return "shr-t";

    default:

      UNREACHABLE();

      return NULL;

  }

}

bool LGoto::HasInterestingComment(LCodeGen* gen) const {

  return !gen->IsNextEmittedBlock(block_id());

}

void LGoto::PrintDataTo(StringStream* stream) {

  stream->Add("B%d", block_id());

}

void LBranch::PrintDataTo(StringStream* stream) {

  stream->Add("B%d | B%d on ", true_block_id(), false_block_id());

  value()->PrintTo(stream);

}

void LCompareNumericAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if ");

  left()->PrintTo(stream);

  stream->Add(" %s ", Token::String(op()));

  right()->PrintTo(stream);

  stream->Add(" then B%d else B%d", true_block_id(), false_block_id());

}

void LIsObjectAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if is_object(");

  value()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LIsStringAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if is_string(");

  value()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LIsSmiAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if is_smi(");

  value()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LIsUndetectableAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if is_undetectable(");

  value()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LStringCompareAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if string_compare(");

  left()->PrintTo(stream);

  right()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LHasInstanceTypeAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if has_instance_type(");

  value()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LHasCachedArrayIndexAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if has_cached_array_index(");

  value()->PrintTo(stream);

  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());

}

void LClassOfTestAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if class_of_test(");

  value()->PrintTo(stream);

  stream->Add(", \"%o\") then B%d else B%d",

              *hydrogen()->class_name(),

              true_block_id(),

              false_block_id());

}

void LTypeofIsAndBranch::PrintDataTo(StringStream* stream) {

  stream->Add("if typeof ");

  value()->PrintTo(stream);

  stream->Add(" == \"%s\" then B%d else B%d",

              *hydrogen()->type_literal()->ToCString(),

              true_block_id(), false_block_id());

}

void LStoreCodeEntry::PrintDataTo(StringStream* stream) {

  stream->Add(" = ");

  function()->PrintTo(stream);

  stream->Add(".code_entry = ");

  code_object()->PrintTo(stream);

}

void LInnerAllocatedObject::PrintDataTo(StringStream* stream) {

  stream->Add(" = ");

  base_object()->PrintTo(stream);

  stream->Add(" + %d", offset());

}

void LCallConstantFunction::PrintDataTo(StringStream* stream) {

  stream->Add("#%d / ", arity());

}

void LLoadContextSlot::PrintDataTo(StringStream* stream) {

  context()->PrintTo(stream);

  stream->Add("[%d]", slot_index());

}

void LStoreContextSlot::PrintDataTo(StringStream* stream) {

  context()->PrintTo(stream);

  stream->Add("[%d] <- ", slot_index());

  value()->PrintTo(stream);

}

void LInvokeFunction::PrintDataTo(StringStream* stream) {

  stream->Add("= ");

  function()->PrintTo(stream);

  stream->Add(" #%d / ", arity());

}

void LCallKeyed::PrintDataTo(StringStream* stream) {

  stream->Add("[r2] #%d / ", arity());

}

void LCallNamed::PrintDataTo(StringStream* stream) {

  SmartArrayPointer<char> name_string = name()->ToCString();

  stream->Add("%s #%d / ", *name_string, arity());

}

void LCallGlobal::PrintDataTo(StringStream* stream) {

  SmartArrayPointer<char> name_string = name()->ToCString();

  stream->Add("%s #%d / ", *name_string, arity());

}

void LCallKnownGlobal::PrintDataTo(StringStream* stream) {

  stream->Add("#%d / ", arity());

}

void LCallNew::PrintDataTo(StringStream* stream) {

  stream->Add("= ");

  constructor()->PrintTo(stream);

  stream->Add(" #%d / ", arity());

}

void LCallNewArray::PrintDataTo(StringStream* stream) {

  stream->Add("= ");

  constructor()->PrintTo(stream);

  stream->Add(" #%d / ", arity());

  ElementsKind kind = hydrogen()->elements_kind();

  stream->Add(" (%s) ", ElementsKindToString(kind));

}

void LAccessArgumentsAt::PrintDataTo(StringStream* stream) {

  arguments()->PrintTo(stream);

  stream->Add(" length ");

  length()->PrintTo(stream);

  stream->Add(" index ");

  index()->PrintTo(stream);

}

void LStoreNamedField::PrintDataTo(StringStream* stream) {

  object()->PrintTo(stream);

  hydrogen()->access().PrintTo(stream);

  stream->Add(" <- ");

  value()->PrintTo(stream);

}

void LStoreNamedGeneric::PrintDataTo(StringStream* stream) {

  object()->PrintTo(stream);

  stream->Add(".");

  stream->Add(*String::cast(*name())->ToCString());

  stream->Add(" <- ");

  value()->PrintTo(stream);

}

void LLoadKeyed::PrintDataTo(StringStream* stream) {

  elements()->PrintTo(stream);

  stream->Add("[");

  key()->PrintTo(stream);

  if (hydrogen()->IsDehoisted()) {

    stream->Add(" + %d]", additional_index());

  } else {

    stream->Add("]");

  }

}

void LStoreKeyed::PrintDataTo(StringStream* stream) {

  elements()->PrintTo(stream);

  stream->Add("[");

  key()->PrintTo(stream);

  if (hydrogen()->IsDehoisted()) {

    stream->Add(" + %d] <-", additional_index());

  } else {

    stream->Add("] <- ");

  }

  if (value() == NULL) {

    ASSERT(hydrogen()->IsConstantHoleStore() &&

           hydrogen()->value()->representation().IsDouble());

    stream->Add("<the hole(nan)>");

  } else {

    value()->PrintTo(stream);

  }

}

void LStoreKeyedGeneric::PrintDataTo(StringStream* stream) {

  object()->PrintTo(stream);

  stream->Add("[");

  key()->PrintTo(stream);

  stream->Add("] <- ");

  value()->PrintTo(stream);

}

void LTransitionElementsKind::PrintDataTo(StringStream* stream) {

  object()->PrintTo(stream);

  stream->Add(" %p -> %p", *original_map(), *transitioned_map());

}

int LPlatformChunk::GetNextSpillIndex(RegisterKind kind) {

  // Skip a slot if for a double-width slot.

  if (kind == DOUBLE_REGISTERS) spill_slot_count_++;

  return spill_slot_count_++;

}

LOperand* LPlatformChunk::GetNextSpillSlot(RegisterKind kind)  {

  int index = GetNextSpillIndex(kind);

  if (kind == DOUBLE_REGISTERS) {

    return LDoubleStackSlot::Create(index, zone());

  } else {

    ASSERT(kind == GENERAL_REGISTERS);

    return LStackSlot::Create(index, zone());

  }

}

LPlatformChunk* LChunkBuilder::Build() {

  ASSERT(is_unused());

  chunk_ = new(zone()) LPlatformChunk(info(), graph());

  LPhase phase("L_Building chunk", chunk_);

  status_ = BUILDING;

  // If compiling for OSR, reserve space for the unoptimized frame,

  // which will be subsumed into this frame.

  if (graph()->has_osr()) {

    for (int i = graph()->osr()->UnoptimizedFrameSlots(); i > 0; i--) {

      chunk_->GetNextSpillIndex(GENERAL_REGISTERS);

    }

  }

  const ZoneList<HBasicBlock*>* blocks = graph()->blocks();

  for (int i = 0; i < blocks->length(); i++) {

    HBasicBlock* next = NULL;

    if (i < blocks->length() - 1) next = blocks->at(i + 1);

    DoBasicBlock(blocks->at(i), next);

    if (is_aborted()) return NULL;

  }

  status_ = DONE;

  return chunk_;

}

void LChunkBuilder::Abort(BailoutReason reason) {

  info()->set_bailout_reason(reason);

  status_ = ABORTED;

}

LUnallocated* LChunkBuilder::ToUnallocated(Register reg) {

  return new(zone()) LUnallocated(LUnallocated::FIXED_REGISTER,

                                  Register::ToAllocationIndex(reg));

}

LUnallocated* LChunkBuilder::ToUnallocated(DoubleRegister reg) {

  return new(zone()) LUnallocated(LUnallocated::FIXED_DOUBLE_REGISTER,

                                  DoubleRegister::ToAllocationIndex(reg));

}

LOperand* LChunkBuilder::UseFixed(HValue* value, Register fixed_register) {

  return Use(value, ToUnallocated(fixed_register));

}

LOperand* LChunkBuilder::UseFixedDouble(HValue* value, DoubleRegister reg) {

  return Use(value, ToUnallocated(reg));

}

LOperand* LChunkBuilder::UseRegister(HValue* value) {

  return Use(value, new(zone()) LUnallocated(LUnallocated::MUST_HAVE_REGISTER));

}

LOperand* LChunkBuilder::UseRegisterAtStart(HValue* value) {

  return Use(value,

             new(zone()) LUnallocated(LUnallocated::MUST_HAVE_REGISTER,

                                      LUnallocated::USED_AT_START));

}

LOperand* LChunkBuilder::UseTempRegister(HValue* value) {

  return Use(value, new(zone()) LUnallocated(LUnallocated::WRITABLE_REGISTER));

}

LOperand* LChunkBuilder::Use(HValue* value) {

  return Use(value, new(zone()) LUnallocated(LUnallocated::NONE));

}

LOperand* LChunkBuilder::UseAtStart(HValue* value) {

  return Use(value, new(zone()) LUnallocated(LUnallocated::NONE,

                                             LUnallocated::USED_AT_START));

}

LOperand* LChunkBuilder::UseOrConstant(HValue* value) {

  return value->IsConstant()

      ? chunk_->DefineConstantOperand(HConstant::cast(value))

      : Use(value);

}

LOperand* LChunkBuilder::UseOrConstantAtStart(HValue* value) {

  return value->IsConstant()

      ? chunk_->DefineConstantOperand(HConstant::cast(value))

      : UseAtStart(value);

}

LOperand* LChunkBuilder::UseRegisterOrConstant(HValue* value) {

  return value->IsConstant()

      ? chunk_->DefineConstantOperand(HConstant::cast(value))

      : UseRegister(value);

}

LOperand* LChunkBuilder::UseRegisterOrConstantAtStart(HValue* value) {

  return value->IsConstant()

      ? chunk_->DefineConstantOperand(HConstant::cast(value))

      : UseRegisterAtStart(value);

}

LOperand* LChunkBuilder::UseConstant(HValue* value) {

  return chunk_->DefineConstantOperand(HConstant::cast(value));

}

LOperand* LChunkBuilder::UseAny(HValue* value) {

  return value->IsConstant()

      ? chunk_->DefineConstantOperand(HConstant::cast(value))

      :  Use(value, new(zone()) LUnallocated(LUnallocated::ANY));

}

LOperand* LChunkBuilder::Use(HValue* value, LUnallocated* operand) {

  if (value->EmitAtUses()) {

    HInstruction* instr = HInstruction::cast(value);

    VisitInstruction(instr);

  }

  operand->set_virtual_register(value->id());

  return operand;

}

template<int I, int T>

LInstruction* LChunkBuilder::Define(LTemplateInstruction<1, I, T>* instr,

                                    LUnallocated* result) {

  result->set_virtual_register(current_instruction_->id());

  instr->set_result(result);

  return instr;

}

template<int I, int T>

LInstruction* LChunkBuilder::DefineAsRegister(

    LTemplateInstruction<1, I, T>* instr) {

  return Define(instr,

                new(zone()) LUnallocated(LUnallocated::MUST_HAVE_REGISTER));

}

template<int I, int T>

LInstruction* LChunkBuilder::DefineAsSpilled(

    LTemplateInstruction<1, I, T>* instr, int index) {

  return Define(instr,

                new(zone()) LUnallocated(LUnallocated::FIXED_SLOT, index));

}

template<int I, int T>

LInstruction* LChunkBuilder::DefineSameAsFirst(

    LTemplateInstruction<1, I, T>* instr) {

  return Define(instr,

                new(zone()) LUnallocated(LUnallocated::SAME_AS_FIRST_INPUT));

}

template<int I, int T>

LInstruction* LChunkBuilder::DefineFixed(

    LTemplateInstruction<1, I, T>* instr, Register reg) {

  return Define(instr, ToUnallocated(reg));

}

template<int I, int T>

LInstruction* LChunkBuilder::DefineFixedDouble(

    LTemplateInstruction<1, I, T>* instr, DoubleRegister reg) {

  return Define(instr, ToUnallocated(reg));

}

LInstruction* LChunkBuilder::AssignEnvironment(LInstruction* instr) {

  HEnvironment* hydrogen_env = current_block_->last_environment();

  int argument_index_accumulator = 0;

  ZoneList<HValue*> objects_to_materialize(0, zone());

  instr->set_environment(CreateEnvironment(hydrogen_env,

                                           &argument_index_accumulator,

                                           &objects_to_materialize));

  return instr;

}

LInstruction* LChunkBuilder::MarkAsCall(LInstruction* instr,

                                        HInstruction* hinstr,

                                        CanDeoptimize can_deoptimize) {

  info()->MarkAsNonDeferredCalling();

#ifdef DEBUG

  instr->VerifyCall();

#endif

  instr->MarkAsCall();

  instr = AssignPointerMap(instr);

  if (hinstr->HasObservableSideEffects()) {

    ASSERT(hinstr->next()->IsSimulate());

    HSimulate* sim = HSimulate::cast(hinstr->next());

    ASSERT(instruction_pending_deoptimization_environment_ == NULL);

    ASSERT(pending_deoptimization_ast_id_.IsNone());

    instruction_pending_deoptimization_environment_ = instr;

    pending_deoptimization_ast_id_ = sim->ast_id();

  }

  // If instruction does not have side-effects lazy deoptimization

  // after the call will try to deoptimize to the point before the call.

  // Thus we still need to attach environment to this call even if

  // call sequence can not deoptimize eagerly.

  bool needs_environment =

      (can_deoptimize == CAN_DEOPTIMIZE_EAGERLY) ||

      !hinstr->HasObservableSideEffects();

  if (needs_environment && !instr->HasEnvironment()) {

    instr = AssignEnvironment(instr);

  }

  return instr;

}

LInstruction* LChunkBuilder::AssignPointerMap(LInstruction* instr) {

  ASSERT(!instr->HasPointerMap());

  instr->set_pointer_map(new(zone()) LPointerMap(zone()));

  return instr;

}

LUnallocated* LChunkBuilder::TempRegister() {

  LUnallocated* operand =

      new(zone()) LUnallocated(LUnallocated::MUST_HAVE_REGISTER);

  int vreg = allocator_->GetVirtualRegister();

  if (!allocator_->AllocationOk()) {

    Abort(kOutOfVirtualRegistersWhileTryingToAllocateTempRegister);

    vreg = 0;

  }

  operand->set_virtual_register(vreg);

  return operand;

}

LOperand* LChunkBuilder::FixedTemp(Register reg) {

  LUnallocated* operand = ToUnallocated(reg);

  ASSERT(operand->HasFixedPolicy());

  return operand;

}

LOperand* LChunkBuilder::FixedTemp(DoubleRegister reg) {

  LUnallocated* operand = ToUnallocated(reg);

  ASSERT(operand->HasFixedPolicy());

  return operand;

}

LInstruction* LChunkBuilder::DoBlockEntry(HBlockEntry* instr) {

  return new(zone()) LLabel(instr->block());

}

LInstruction* LChunkBuilder::DoDummyUse(HDummyUse* instr) {

  return DefineAsRegister(new(zone()) LDummyUse(UseAny(instr->value())));

}

LInstruction* LChunkBuilder::DoEnvironmentMarker(HEnvironmentMarker* instr) {

  UNREACHABLE();

  return NULL;

}

LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {

  return AssignEnvironment(new(zone()) LDeoptimize);

}

LInstruction* LChunkBuilder::DoShift(Token::Value op,

                                     HBitwiseBinaryOperation* instr) {

  if (instr->representation().IsSmiOrInteger32()) {

    ASSERT(instr->left()->representation().Equals(instr->representation()));

    ASSERT(instr->right()->representation().Equals(instr->representation()));

    LOperand* left = UseRegisterAtStart(instr->left());

    HValue* right_value = instr->right();

    LOperand* right = NULL;

    int constant_value = 0;

    bool does_deopt = false;

    if (right_value->IsConstant()) {

      HConstant* constant = HConstant::cast(right_value);

      right = chunk_->DefineConstantOperand(constant);

      constant_value = constant->Integer32Value() & 0x1f;

      // Left shifts can deoptimize if we shift by > 0 and the result cannot be

      // truncated to smi.

      if (instr->representation().IsSmi() && constant_value > 0) {

        does_deopt = !instr->CheckUsesForFlag(HValue::kTruncatingToSmi);

      }

    } else {

      right = UseRegisterAtStart(right_value);

    }

    // Shift operations can only deoptimize if we do a logical shift

    // by 0 and the result cannot be truncated to int32.

    if (op == Token::SHR && constant_value == 0) {

      if (FLAG_opt_safe_uint32_operations) {

        does_deopt = !instr->CheckFlag(HInstruction::kUint32);

      } else {

        does_deopt = !instr->CheckUsesForFlag(HValue::kTruncatingToInt32);

      }

    }

    LInstruction* result =

        DefineAsRegister(new(zone()) LShiftI(op, left, right, does_deopt));

    return does_deopt ? AssignEnvironment(result) : result;

  } else {

    return DoArithmeticT(op, instr);

  }

}

LInstruction* LChunkBuilder::DoArithmeticD(Token::Value op,

                                           HArithmeticBinaryOperation* instr) {

  ASSERT(instr->representation().IsDouble());

  ASSERT(instr->left()->representation().IsDouble());

  ASSERT(instr->right()->representation().IsDouble());

  if (op == Token::MOD) {

    LOperand* left = UseFixedDouble(instr->left(), d1);

    LOperand* right = UseFixedDouble(instr->right(), d2);

    LArithmeticD* result = new(zone()) LArithmeticD(op, left, right);

    // We call a C function for double modulo. It can't trigger a GC. We need

    // to use fixed result register for the call.

    // TODO(fschneider): Allow any register as input registers.

    return MarkAsCall(DefineFixedDouble(result, d1), instr);

  } else {

    LOperand* left = UseRegisterAtStart(instr->left());

    LOperand* right = UseRegisterAtStart(instr->right());

    LArithmeticD* result = new(zone()) LArithmeticD(op, left, right);

    return DefineAsRegister(result);

  }

}

LInstruction* LChunkBuilder::DoArithmeticT(Token::Value op,

                                           HBinaryOperation* instr) {

  HValue* left = instr->left();

  HValue* right = instr->right();

  ASSERT(left->representation().IsTagged());

  ASSERT(right->representation().IsTagged());

  LOperand* context = UseFixed(instr->context(), cp);

  LOperand* left_operand = UseFixed(left, r1);

  LOperand* right_operand = UseFixed(right, r0);

  LArithmeticT* result =

      new(zone()) LArithmeticT(op, context, left_operand, right_operand);

  return MarkAsCall(DefineFixed(result, r0), instr);

}

void LChunkBuilder::DoBasicBlock(HBasicBlock* block, HBasicBlock* next_block) {

  ASSERT(is_building());

  current_block_ = block;

  next_block_ = next_block;

  if (block->IsStartBlock()) {

    block->UpdateEnvironment(graph_->start_environment());

    argument_count_ = 0;

  } else if (block->predecessors()->length() == 1) {

    // We have a single predecessor => copy environment and outgoing

    // argument count from the predecessor.

    ASSERT(block->phis()->length() == 0);

    HBasicBlock* pred = block->predecessors()->at(0);

    HEnvironment* last_environment = pred->last_environment();

    ASSERT(last_environment != NULL);

    // Only copy the environment, if it is later used again.

    if (pred->end()->SecondSuccessor() == NULL) {

      ASSERT(pred->end()->FirstSuccessor() == block);

    } else {

      if (pred->end()->FirstSuccessor()->block_id() > block->block_id() ||

          pred->end()->SecondSuccessor()->block_id() > block->block_id()) {

        last_environment = last_environment->Copy();

      }

    }

    block->UpdateEnvironment(last_environment);

    ASSERT(pred->argument_count() >= 0);

    argument_count_ = pred->argument_count();

  } else {

    // We are at a state join => process phis.

    HBasicBlock* pred = block->predecessors()->at(0);

    // No need to copy the environment, it cannot be used later.

    HEnvironment* last_environment = pred->last_environment();

    for (int i = 0; i < block->phis()->length(); ++i) {

      HPhi* phi = block->phis()->at(i);

      if (phi->HasMergedIndex()) {

        last_environment->SetValueAt(phi->merged_index(), phi);

      }

    }

    for (int i = 0; i < block->deleted_phis()->length(); ++i) {

      if (block->deleted_phis()->at(i) < last_environment->length()) {

        last_environment->SetValueAt(block->deleted_phis()->at(i),

                                     graph_->GetConstantUndefined());

      }

    }

    block->UpdateEnvironment(last_environment);

    // Pick up the outgoing argument count of one of the predecessors.

    argument_count_ = pred->argument_count();

  }

  HInstruction* current = block->first();

  int start = chunk_->instructions()->length();

  while (current != NULL && !is_aborted()) {

    // Code for constants in registers is generated lazily.

    if (!current->EmitAtUses()) {

      VisitInstruction(current);

    }

    current = current->next();

  }

  int end = chunk_->instructions()->length() - 1;

  if (end >= start) {

    block->set_first_instruction_index(start);

    block->set_last_instruction_index(end);

  }

  block->set_argument_count(argument_count_);

  next_block_ = NULL;

  current_block_ = NULL;

}

void LChunkBuilder::VisitInstruction(HInstruction* current) {

  HInstruction* old_current = current_instruction_;

  current_instruction_ = current;

  if (current->has_position()) position_ = current->position();

  LInstruction* instr = NULL;

  if (current->CanReplaceWithDummyUses()) {

    HValue* first_operand = current->OperandCount() == 0

        ? graph()->GetConstant1()

        : current->OperandAt(0);

    instr = DefineAsRegister(new(zone()) LDummyUse(UseAny(first_operand)));

    for (int i = 1; i < current->OperandCount(); ++i) {

      LInstruction* dummy =

          new(zone()) LDummyUse(UseAny(current->OperandAt(i)));

      dummy->set_hydrogen_value(current);

      chunk_->AddInstruction(dummy, current_block_);

    }

  } else {

    instr = current->CompileToLithium(this);

  }

  argument_count_ += current->argument_delta();

  ASSERT(argument_count_ >= 0);

  if (instr != NULL) {

    // Associate the hydrogen instruction first, since we may need it for

    // the ClobbersRegisters() or ClobbersDoubleRegisters() calls below.

    instr->set_hydrogen_value(current);

#if DEBUG

    // Make sure that the lithium instruction has either no fixed register

    // constraints in temps or the result OR no uses that are only used at

    // start. If this invariant doesn't hold, the register allocator can decide

    // to insert a split of a range immediately before the instruction due to an

    // already allocated register needing to be used for the instruction's fixed

    // register constraint. In this case, The register allocator won't see an

    // interference between the split child and the use-at-start (it would if

    // the it was just a plain use), so it is free to move the split child into

    // the same register that is used for the use-at-start.

    // See https://code.google.com/p/chromium/issues/detail?id=201590

    if (!(instr->ClobbersRegisters() && instr->ClobbersDoubleRegisters())) {

      int fixed = 0;

      int used_at_start = 0;

      for (UseIterator it(instr); !it.Done(); it.Advance()) {

        LUnallocated* operand = LUnallocated::cast(it.Current());

        if (operand->IsUsedAtStart()) ++used_at_start;

      }

      if (instr->Output() != NULL) {

        if (LUnallocated::cast(instr->Output())->HasFixedPolicy()) ++fixed;

      }

      for (TempIterator it(instr); !it.Done(); it.Advance()) {

        LUnallocated* operand = LUnallocated::cast(it.Current());

        if (operand->HasFixedPolicy()) ++fixed;

      }

      ASSERT(fixed == 0 || used_at_start == 0);

    }

#endif

    if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {

      instr = AssignPointerMap(instr);

    }

    if (FLAG_stress_environments && !instr->HasEnvironment()) {

      instr = AssignEnvironment(instr);

    }

    chunk_->AddInstruction(instr, current_block_);

  }

  current_instruction_ = old_current;

}

LEnvironment* LChunkBuilder::CreateEnvironment(

    HEnvironment* hydrogen_env,

    int* argument_index_accumulator,

    ZoneList<HValue*>* objects_to_materialize) {

  if (hydrogen_env == NULL) return NULL;

  LEnvironment* outer = CreateEnvironment(hydrogen_env->outer(),

                                          argument_index_accumulator,

                                          objects_to_materialize);

  BailoutId ast_id = hydrogen_env->ast_id();

  ASSERT(!ast_id.IsNone() ||

         hydrogen_env->frame_type() != JS_FUNCTION);

  int value_count = hydrogen_env->length() - hydrogen_env->specials_count();

  LEnvironment* result = new(zone()) LEnvironment(

      hydrogen_env->closure(),

      hydrogen_env->frame_type(),

      ast_id,

      hydrogen_env->parameter_count(),

      argument_count_,

      value_count,

      outer,

      hydrogen_env->entry(),

      zone());

  int argument_index = *argument_index_accumulator;

  int object_index = objects_to_materialize->length();

  for (int i = 0; i < hydrogen_env->length(); ++i) {

    if (hydrogen_env->is_special_index(i)) continue;

    LOperand* op;

    HValue* value = hydrogen_env->values()->at(i);

    if (value->IsArgumentsObject() || value->IsCapturedObject()) {

      objects_to_materialize->Add(value, zone());

      op = LEnvironment::materialization_marker();

    } else if (value->IsPushArgument()) {

      op = new(zone()) LArgument(argument_index++);

    } else {

      op = UseAny(value);

    }

    result->AddValue(op,

                     value->representation(),

                     value->CheckFlag(HInstruction::kUint32));

  }

  for (int i = object_index; i < objects_to_materialize->length(); ++i) {

    HValue* object_to_materialize = objects_to_materialize->at(i);

    int previously_materialized_object = -1;

    for (int prev = 0; prev < i; ++prev) {

      if (objects_to_materialize->at(prev) == objects_to_materialize->at(i)) {

        previously_materialized_object = prev;