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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "src/lithium.h"
      6 
      7 #include "src/v8.h"
      8 
      9 #include "src/scopes.h"
     10 #include "src/serialize.h"
     11 
     12 #if V8_TARGET_ARCH_IA32
     13 #include "src/ia32/lithium-ia32.h"  // NOLINT
     14 #include "src/ia32/lithium-codegen-ia32.h"  // NOLINT
     15 #elif V8_TARGET_ARCH_X64
     16 #include "src/x64/lithium-x64.h"  // NOLINT
     17 #include "src/x64/lithium-codegen-x64.h"  // NOLINT
     18 #elif V8_TARGET_ARCH_ARM
     19 #include "src/arm/lithium-arm.h"  // NOLINT
     20 #include "src/arm/lithium-codegen-arm.h"  // NOLINT
     21 #elif V8_TARGET_ARCH_MIPS
     22 #include "src/mips/lithium-mips.h"  // NOLINT
     23 #include "src/mips/lithium-codegen-mips.h"  // NOLINT
     24 #elif V8_TARGET_ARCH_ARM64
     25 #include "src/arm64/lithium-arm64.h"  // NOLINT
     26 #include "src/arm64/lithium-codegen-arm64.h"  // NOLINT
     27 #elif V8_TARGET_ARCH_MIPS64
     28 #include "src/mips64/lithium-mips64.h"  // NOLINT
     29 #include "src/mips64/lithium-codegen-mips64.h"  // NOLINT
     30 #elif V8_TARGET_ARCH_X87
     31 #include "src/x87/lithium-x87.h"  // NOLINT
     32 #include "src/x87/lithium-codegen-x87.h"  // NOLINT
     33 #else
     34 #error "Unknown architecture."
     35 #endif
     36 
     37 namespace v8 {
     38 namespace internal {
     39 
     40 
     41 void LOperand::PrintTo(StringStream* stream) {
     42   LUnallocated* unalloc = NULL;
     43   switch (kind()) {
     44     case INVALID:
     45       stream->Add("(0)");
     46       break;
     47     case UNALLOCATED:
     48       unalloc = LUnallocated::cast(this);
     49       stream->Add("v%d", unalloc->virtual_register());
     50       if (unalloc->basic_policy() == LUnallocated::FIXED_SLOT) {
     51         stream->Add("(=%dS)", unalloc->fixed_slot_index());
     52         break;
     53       }
     54       switch (unalloc->extended_policy()) {
     55         case LUnallocated::NONE:
     56           break;
     57         case LUnallocated::FIXED_REGISTER: {
     58           int reg_index = unalloc->fixed_register_index();
     59           if (reg_index < 0 ||
     60               reg_index >= Register::kMaxNumAllocatableRegisters) {
     61             stream->Add("(=invalid_reg#%d)", reg_index);
     62           } else {
     63             const char* register_name =
     64                 Register::AllocationIndexToString(reg_index);
     65             stream->Add("(=%s)", register_name);
     66           }
     67           break;
     68         }
     69         case LUnallocated::FIXED_DOUBLE_REGISTER: {
     70           int reg_index = unalloc->fixed_register_index();
     71           if (reg_index < 0 ||
     72               reg_index >= DoubleRegister::kMaxNumAllocatableRegisters) {
     73             stream->Add("(=invalid_double_reg#%d)", reg_index);
     74           } else {
     75             const char* double_register_name =
     76                 DoubleRegister::AllocationIndexToString(reg_index);
     77             stream->Add("(=%s)", double_register_name);
     78           }
     79           break;
     80         }
     81         case LUnallocated::MUST_HAVE_REGISTER:
     82           stream->Add("(R)");
     83           break;
     84         case LUnallocated::MUST_HAVE_DOUBLE_REGISTER:
     85           stream->Add("(D)");
     86           break;
     87         case LUnallocated::WRITABLE_REGISTER:
     88           stream->Add("(WR)");
     89           break;
     90         case LUnallocated::SAME_AS_FIRST_INPUT:
     91           stream->Add("(1)");
     92           break;
     93         case LUnallocated::ANY:
     94           stream->Add("(-)");
     95           break;
     96       }
     97       break;
     98     case CONSTANT_OPERAND:
     99       stream->Add("[constant:%d]", index());
    100       break;
    101     case STACK_SLOT:
    102       stream->Add("[stack:%d]", index());
    103       break;
    104     case DOUBLE_STACK_SLOT:
    105       stream->Add("[double_stack:%d]", index());
    106       break;
    107     case REGISTER: {
    108       int reg_index = index();
    109       if (reg_index < 0 || reg_index >= Register::kMaxNumAllocatableRegisters) {
    110         stream->Add("(=invalid_reg#%d|R)", reg_index);
    111       } else {
    112         stream->Add("[%s|R]", Register::AllocationIndexToString(reg_index));
    113       }
    114       break;
    115     }
    116     case DOUBLE_REGISTER: {
    117       int reg_index = index();
    118       if (reg_index < 0 ||
    119           reg_index >= DoubleRegister::kMaxNumAllocatableRegisters) {
    120         stream->Add("(=invalid_double_reg#%d|R)", reg_index);
    121       } else {
    122         stream->Add("[%s|R]",
    123                     DoubleRegister::AllocationIndexToString(reg_index));
    124       }
    125       break;
    126     }
    127   }
    128 }
    129 
    130 
    131 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
    132 LSubKindOperand<kOperandKind, kNumCachedOperands>*
    133 LSubKindOperand<kOperandKind, kNumCachedOperands>::cache = NULL;
    134 
    135 
    136 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
    137 void LSubKindOperand<kOperandKind, kNumCachedOperands>::SetUpCache() {
    138   if (cache) return;
    139   cache = new LSubKindOperand[kNumCachedOperands];
    140   for (int i = 0; i < kNumCachedOperands; i++) {
    141     cache[i].ConvertTo(kOperandKind, i);
    142   }
    143 }
    144 
    145 
    146 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
    147 void LSubKindOperand<kOperandKind, kNumCachedOperands>::TearDownCache() {
    148   delete[] cache;
    149   cache = NULL;
    150 }
    151 
    152 
    153 void LOperand::SetUpCaches() {
    154 #define LITHIUM_OPERAND_SETUP(name, type, number) L##name::SetUpCache();
    155   LITHIUM_OPERAND_LIST(LITHIUM_OPERAND_SETUP)
    156 #undef LITHIUM_OPERAND_SETUP
    157 }
    158 
    159 
    160 void LOperand::TearDownCaches() {
    161 #define LITHIUM_OPERAND_TEARDOWN(name, type, number) L##name::TearDownCache();
    162   LITHIUM_OPERAND_LIST(LITHIUM_OPERAND_TEARDOWN)
    163 #undef LITHIUM_OPERAND_TEARDOWN
    164 }
    165 
    166 
    167 bool LParallelMove::IsRedundant() const {
    168   for (int i = 0; i < move_operands_.length(); ++i) {
    169     if (!move_operands_[i].IsRedundant()) return false;
    170   }
    171   return true;
    172 }
    173 
    174 
    175 void LParallelMove::PrintDataTo(StringStream* stream) const {
    176   bool first = true;
    177   for (int i = 0; i < move_operands_.length(); ++i) {
    178     if (!move_operands_[i].IsEliminated()) {
    179       LOperand* source = move_operands_[i].source();
    180       LOperand* destination = move_operands_[i].destination();
    181       if (!first) stream->Add(" ");
    182       first = false;
    183       if (source->Equals(destination)) {
    184         destination->PrintTo(stream);
    185       } else {
    186         destination->PrintTo(stream);
    187         stream->Add(" = ");
    188         source->PrintTo(stream);
    189       }
    190       stream->Add(";");
    191     }
    192   }
    193 }
    194 
    195 
    196 void LEnvironment::PrintTo(StringStream* stream) {
    197   stream->Add("[id=%d|", ast_id().ToInt());
    198   if (deoptimization_index() != Safepoint::kNoDeoptimizationIndex) {
    199     stream->Add("deopt_id=%d|", deoptimization_index());
    200   }
    201   stream->Add("parameters=%d|", parameter_count());
    202   stream->Add("arguments_stack_height=%d|", arguments_stack_height());
    203   for (int i = 0; i < values_.length(); ++i) {
    204     if (i != 0) stream->Add(";");
    205     if (values_[i] == NULL) {
    206       stream->Add("[hole]");
    207     } else {
    208       values_[i]->PrintTo(stream);
    209     }
    210   }
    211   stream->Add("]");
    212 }
    213 
    214 
    215 void LPointerMap::RecordPointer(LOperand* op, Zone* zone) {
    216   // Do not record arguments as pointers.
    217   if (op->IsStackSlot() && op->index() < 0) return;
    218   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot());
    219   pointer_operands_.Add(op, zone);
    220 }
    221 
    222 
    223 void LPointerMap::RemovePointer(LOperand* op) {
    224   // Do not record arguments as pointers.
    225   if (op->IsStackSlot() && op->index() < 0) return;
    226   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot());
    227   for (int i = 0; i < pointer_operands_.length(); ++i) {
    228     if (pointer_operands_[i]->Equals(op)) {
    229       pointer_operands_.Remove(i);
    230       --i;
    231     }
    232   }
    233 }
    234 
    235 
    236 void LPointerMap::RecordUntagged(LOperand* op, Zone* zone) {
    237   // Do not record arguments as pointers.
    238   if (op->IsStackSlot() && op->index() < 0) return;
    239   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot());
    240   untagged_operands_.Add(op, zone);
    241 }
    242 
    243 
    244 void LPointerMap::PrintTo(StringStream* stream) {
    245   stream->Add("{");
    246   for (int i = 0; i < pointer_operands_.length(); ++i) {
    247     if (i != 0) stream->Add(";");
    248     pointer_operands_[i]->PrintTo(stream);
    249   }
    250   stream->Add("}");
    251 }
    252 
    253 
    254 int StackSlotOffset(int index) {
    255   if (index >= 0) {
    256     // Local or spill slot. Skip the frame pointer, function, and
    257     // context in the fixed part of the frame.
    258     return -(index + 1) * kPointerSize -
    259         StandardFrameConstants::kFixedFrameSizeFromFp;
    260   } else {
    261     // Incoming parameter. Skip the return address.
    262     return -(index + 1) * kPointerSize + kFPOnStackSize + kPCOnStackSize;
    263   }
    264 }
    265 
    266 
    267 LChunk::LChunk(CompilationInfo* info, HGraph* graph)
    268     : spill_slot_count_(0),
    269       info_(info),
    270       graph_(graph),
    271       instructions_(32, info->zone()),
    272       pointer_maps_(8, info->zone()),
    273       inlined_closures_(1, info->zone()),
    274       deprecation_dependencies_(MapLess(), MapAllocator(info->zone())),
    275       stability_dependencies_(MapLess(), MapAllocator(info->zone())) {}
    276 
    277 
    278 LLabel* LChunk::GetLabel(int block_id) const {
    279   HBasicBlock* block = graph_->blocks()->at(block_id);
    280   int first_instruction = block->first_instruction_index();
    281   return LLabel::cast(instructions_[first_instruction]);
    282 }
    283 
    284 
    285 int LChunk::LookupDestination(int block_id) const {
    286   LLabel* cur = GetLabel(block_id);
    287   while (cur->replacement() != NULL) {
    288     cur = cur->replacement();
    289   }
    290   return cur->block_id();
    291 }
    292 
    293 Label* LChunk::GetAssemblyLabel(int block_id) const {
    294   LLabel* label = GetLabel(block_id);
    295   DCHECK(!label->HasReplacement());
    296   return label->label();
    297 }
    298 
    299 
    300 void LChunk::MarkEmptyBlocks() {
    301   LPhase phase("L_Mark empty blocks", this);
    302   for (int i = 0; i < graph()->blocks()->length(); ++i) {
    303     HBasicBlock* block = graph()->blocks()->at(i);
    304     int first = block->first_instruction_index();
    305     int last = block->last_instruction_index();
    306     LInstruction* first_instr = instructions()->at(first);
    307     LInstruction* last_instr = instructions()->at(last);
    308 
    309     LLabel* label = LLabel::cast(first_instr);
    310     if (last_instr->IsGoto()) {
    311       LGoto* goto_instr = LGoto::cast(last_instr);
    312       if (label->IsRedundant() &&
    313           !label->is_loop_header()) {
    314         bool can_eliminate = true;
    315         for (int i = first + 1; i < last && can_eliminate; ++i) {
    316           LInstruction* cur = instructions()->at(i);
    317           if (cur->IsGap()) {
    318             LGap* gap = LGap::cast(cur);
    319             if (!gap->IsRedundant()) {
    320               can_eliminate = false;
    321             }
    322           } else {
    323             can_eliminate = false;
    324           }
    325         }
    326         if (can_eliminate) {
    327           label->set_replacement(GetLabel(goto_instr->block_id()));
    328         }
    329       }
    330     }
    331   }
    332 }
    333 
    334 
    335 void LChunk::AddInstruction(LInstruction* instr, HBasicBlock* block) {
    336   LInstructionGap* gap = new (zone()) LInstructionGap(block);
    337   gap->set_hydrogen_value(instr->hydrogen_value());
    338   int index = -1;
    339   if (instr->IsControl()) {
    340     instructions_.Add(gap, zone());
    341     index = instructions_.length();
    342     instructions_.Add(instr, zone());
    343   } else {
    344     index = instructions_.length();
    345     instructions_.Add(instr, zone());
    346     instructions_.Add(gap, zone());
    347   }
    348   if (instr->HasPointerMap()) {
    349     pointer_maps_.Add(instr->pointer_map(), zone());
    350     instr->pointer_map()->set_lithium_position(index);
    351   }
    352 }
    353 
    354 
    355 LConstantOperand* LChunk::DefineConstantOperand(HConstant* constant) {
    356   return LConstantOperand::Create(constant->id(), zone());
    357 }
    358 
    359 
    360 int LChunk::GetParameterStackSlot(int index) const {
    361   // The receiver is at index 0, the first parameter at index 1, so we
    362   // shift all parameter indexes down by the number of parameters, and
    363   // make sure they end up negative so they are distinguishable from
    364   // spill slots.
    365   int result = index - info()->num_parameters() - 1;
    366 
    367   DCHECK(result < 0);
    368   return result;
    369 }
    370 
    371 
    372 // A parameter relative to ebp in the arguments stub.
    373 int LChunk::ParameterAt(int index) {
    374   DCHECK(-1 <= index);  // -1 is the receiver.
    375   return (1 + info()->scope()->num_parameters() - index) *
    376       kPointerSize;
    377 }
    378 
    379 
    380 LGap* LChunk::GetGapAt(int index) const {
    381   return LGap::cast(instructions_[index]);
    382 }
    383 
    384 
    385 bool LChunk::IsGapAt(int index) const {
    386   return instructions_[index]->IsGap();
    387 }
    388 
    389 
    390 int LChunk::NearestGapPos(int index) const {
    391   while (!IsGapAt(index)) index--;
    392   return index;
    393 }
    394 
    395 
    396 void LChunk::AddGapMove(int index, LOperand* from, LOperand* to) {
    397   GetGapAt(index)->GetOrCreateParallelMove(
    398       LGap::START, zone())->AddMove(from, to, zone());
    399 }
    400 
    401 
    402 HConstant* LChunk::LookupConstant(LConstantOperand* operand) const {
    403   return HConstant::cast(graph_->LookupValue(operand->index()));
    404 }
    405 
    406 
    407 Representation LChunk::LookupLiteralRepresentation(
    408     LConstantOperand* operand) const {
    409   return graph_->LookupValue(operand->index())->representation();
    410 }
    411 
    412 
    413 void LChunk::CommitDependencies(Handle<Code> code) const {
    414   for (MapSet::const_iterator it = deprecation_dependencies_.begin(),
    415        iend = deprecation_dependencies_.end(); it != iend; ++it) {
    416     Handle<Map> map = *it;
    417     DCHECK(!map->is_deprecated());
    418     DCHECK(map->CanBeDeprecated());
    419     Map::AddDependentCode(map, DependentCode::kTransitionGroup, code);
    420   }
    421 
    422   for (MapSet::const_iterator it = stability_dependencies_.begin(),
    423        iend = stability_dependencies_.end(); it != iend; ++it) {
    424     Handle<Map> map = *it;
    425     DCHECK(map->is_stable());
    426     DCHECK(map->CanTransition());
    427     Map::AddDependentCode(map, DependentCode::kPrototypeCheckGroup, code);
    428   }
    429 
    430   info_->CommitDependencies(code);
    431 }
    432 
    433 
    434 LChunk* LChunk::NewChunk(HGraph* graph) {
    435   DisallowHandleAllocation no_handles;
    436   DisallowHeapAllocation no_gc;
    437   graph->DisallowAddingNewValues();
    438   int values = graph->GetMaximumValueID();
    439   CompilationInfo* info = graph->info();
    440   if (values > LUnallocated::kMaxVirtualRegisters) {
    441     info->AbortOptimization(kNotEnoughVirtualRegistersForValues);
    442     return NULL;
    443   }
    444   LAllocator allocator(values, graph);
    445   LChunkBuilder builder(info, graph, &allocator);
    446   LChunk* chunk = builder.Build();
    447   if (chunk == NULL) return NULL;
    448 
    449   if (!allocator.Allocate(chunk)) {
    450     info->AbortOptimization(kNotEnoughVirtualRegistersRegalloc);
    451     return NULL;
    452   }
    453 
    454   chunk->set_allocated_double_registers(
    455       allocator.assigned_double_registers());
    456 
    457   return chunk;
    458 }
    459 
    460 
    461 Handle<Code> LChunk::Codegen() {
    462   MacroAssembler assembler(info()->isolate(), NULL, 0);
    463   LOG_CODE_EVENT(info()->isolate(),
    464                  CodeStartLinePosInfoRecordEvent(
    465                      assembler.positions_recorder()));
    466   // TODO(yangguo) remove this once the code serializer handles code stubs.
    467   if (info()->will_serialize()) assembler.enable_serializer();
    468   LCodeGen generator(this, &assembler, info());
    469 
    470   MarkEmptyBlocks();
    471 
    472   if (generator.GenerateCode()) {
    473     generator.CheckEnvironmentUsage();
    474     CodeGenerator::MakeCodePrologue(info(), "optimized");
    475     Code::Flags flags = info()->flags();
    476     Handle<Code> code =
    477         CodeGenerator::MakeCodeEpilogue(&assembler, flags, info());
    478     generator.FinishCode(code);
    479     CommitDependencies(code);
    480     code->set_is_crankshafted(true);
    481     void* jit_handler_data =
    482         assembler.positions_recorder()->DetachJITHandlerData();
    483     LOG_CODE_EVENT(info()->isolate(),
    484                    CodeEndLinePosInfoRecordEvent(*code, jit_handler_data));
    485 
    486     CodeGenerator::PrintCode(code, info());
    487     DCHECK(!(info()->isolate()->serializer_enabled() &&
    488              info()->GetMustNotHaveEagerFrame() &&
    489              generator.NeedsEagerFrame()));
    490     return code;
    491   }
    492   assembler.AbortedCodeGeneration();
    493   return Handle<Code>::null();
    494 }
    495 
    496 
    497 void LChunk::set_allocated_double_registers(BitVector* allocated_registers) {
    498   allocated_double_registers_ = allocated_registers;
    499   BitVector* doubles = allocated_double_registers();
    500   BitVector::Iterator iterator(doubles);
    501   while (!iterator.Done()) {
    502     if (info()->saves_caller_doubles()) {
    503       if (kDoubleSize == kPointerSize * 2) {
    504         spill_slot_count_ += 2;
    505       } else {
    506         spill_slot_count_++;
    507       }
    508     }
    509     iterator.Advance();
    510   }
    511 }
    512 
    513 
    514 void LChunkBuilderBase::Abort(BailoutReason reason) {
    515   info()->AbortOptimization(reason);
    516   status_ = ABORTED;
    517 }
    518 
    519 
    520 void LChunkBuilderBase::Retry(BailoutReason reason) {
    521   info()->RetryOptimization(reason);
    522   status_ = ABORTED;
    523 }
    524 
    525 
    526 LEnvironment* LChunkBuilderBase::CreateEnvironment(
    527     HEnvironment* hydrogen_env, int* argument_index_accumulator,
    528     ZoneList<HValue*>* objects_to_materialize) {
    529   if (hydrogen_env == NULL) return NULL;
    530 
    531   LEnvironment* outer =
    532       CreateEnvironment(hydrogen_env->outer(), argument_index_accumulator,
    533                         objects_to_materialize);
    534   BailoutId ast_id = hydrogen_env->ast_id();
    535   DCHECK(!ast_id.IsNone() ||
    536          hydrogen_env->frame_type() != JS_FUNCTION);
    537 
    538   int omitted_count = (hydrogen_env->frame_type() == JS_FUNCTION)
    539                           ? 0
    540                           : hydrogen_env->specials_count();
    541 
    542   int value_count = hydrogen_env->length() - omitted_count;
    543   LEnvironment* result =
    544       new(zone()) LEnvironment(hydrogen_env->closure(),
    545                                hydrogen_env->frame_type(),
    546                                ast_id,
    547                                hydrogen_env->parameter_count(),
    548                                argument_count_,
    549                                value_count,
    550                                outer,
    551                                hydrogen_env->entry(),
    552                                zone());
    553   int argument_index = *argument_index_accumulator;
    554 
    555   // Store the environment description into the environment
    556   // (with holes for nested objects)
    557   for (int i = 0; i < hydrogen_env->length(); ++i) {
    558     if (hydrogen_env->is_special_index(i) &&
    559         hydrogen_env->frame_type() != JS_FUNCTION) {
    560       continue;
    561     }
    562     LOperand* op;
    563     HValue* value = hydrogen_env->values()->at(i);
    564     CHECK(!value->IsPushArguments());  // Do not deopt outgoing arguments
    565     if (value->IsArgumentsObject() || value->IsCapturedObject()) {
    566       op = LEnvironment::materialization_marker();
    567     } else {
    568       op = UseAny(value);
    569     }
    570     result->AddValue(op,
    571                      value->representation(),
    572                      value->CheckFlag(HInstruction::kUint32));
    573   }
    574 
    575   // Recursively store the nested objects into the environment
    576   for (int i = 0; i < hydrogen_env->length(); ++i) {
    577     if (hydrogen_env->is_special_index(i)) continue;
    578 
    579     HValue* value = hydrogen_env->values()->at(i);
    580     if (value->IsArgumentsObject() || value->IsCapturedObject()) {
    581       AddObjectToMaterialize(value, objects_to_materialize, result);
    582     }
    583   }
    584 
    585   if (hydrogen_env->frame_type() == JS_FUNCTION) {
    586     *argument_index_accumulator = argument_index;
    587   }
    588 
    589   return result;
    590 }
    591 
    592 
    593 // Add an object to the supplied environment and object materialization list.
    594 //
    595 // Notes:
    596 //
    597 // We are building three lists here:
    598 //
    599 // 1. In the result->object_mapping_ list (added to by the
    600 //    LEnvironment::Add*Object methods), we store the lengths (number
    601 //    of fields) of the captured objects in depth-first traversal order, or
    602 //    in case of duplicated objects, we store the index to the duplicate object
    603 //    (with a tag to differentiate between captured and duplicated objects).
    604 //
    605 // 2. The object fields are stored in the result->values_ list
    606 //    (added to by the LEnvironment.AddValue method) sequentially as lists
    607 //    of fields with holes for nested objects (the holes will be expanded
    608 //    later by LCodegen::AddToTranslation according to the
    609 //    LEnvironment.object_mapping_ list).
    610 //
    611 // 3. The auxiliary objects_to_materialize array stores the hydrogen values
    612 //    in the same order as result->object_mapping_ list. This is used
    613 //    to detect duplicate values and calculate the corresponding object index.
    614 void LChunkBuilderBase::AddObjectToMaterialize(HValue* value,
    615     ZoneList<HValue*>* objects_to_materialize, LEnvironment* result) {
    616   int object_index = objects_to_materialize->length();
    617   // Store the hydrogen value into the de-duplication array
    618   objects_to_materialize->Add(value, zone());
    619   // Find out whether we are storing a duplicated value
    620   int previously_materialized_object = -1;
    621   for (int prev = 0; prev < object_index; ++prev) {
    622     if (objects_to_materialize->at(prev) == value) {
    623       previously_materialized_object = prev;
    624       break;
    625     }
    626   }
    627   // Store the captured object length (or duplicated object index)
    628   // into the environment. For duplicated objects, we stop here.
    629   int length = value->OperandCount();
    630   bool is_arguments = value->IsArgumentsObject();
    631   if (previously_materialized_object >= 0) {
    632     result->AddDuplicateObject(previously_materialized_object);
    633     return;
    634   } else {
    635     result->AddNewObject(is_arguments ? length - 1 : length, is_arguments);
    636   }
    637   // Store the captured object's fields into the environment
    638   for (int i = is_arguments ? 1 : 0; i < length; ++i) {
    639     LOperand* op;
    640     HValue* arg_value = value->OperandAt(i);
    641     if (arg_value->IsArgumentsObject() || arg_value->IsCapturedObject()) {
    642       // Insert a hole for nested objects
    643       op = LEnvironment::materialization_marker();
    644     } else {
    645       DCHECK(!arg_value->IsPushArguments());
    646       // For ordinary values, tell the register allocator we need the value
    647       // to be alive here
    648       op = UseAny(arg_value);
    649     }
    650     result->AddValue(op,
    651                      arg_value->representation(),
    652                      arg_value->CheckFlag(HInstruction::kUint32));
    653   }
    654   // Recursively store all the nested captured objects into the environment
    655   for (int i = is_arguments ? 1 : 0; i < length; ++i) {
    656     HValue* arg_value = value->OperandAt(i);
    657     if (arg_value->IsArgumentsObject() || arg_value->IsCapturedObject()) {
    658       AddObjectToMaterialize(arg_value, objects_to_materialize, result);
    659     }
    660   }
    661 }
    662 
    663 
    664 LPhase::~LPhase() {
    665   if (ShouldProduceTraceOutput()) {
    666     isolate()->GetHTracer()->TraceLithium(name(), chunk_);
    667   }
    668 }
    669 
    670 
    671 } }  // namespace v8::internal
    672