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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/crankshaft/lithium.h"
      6 
      7 #include "src/ast/scopes.h"
      8 
      9 #if V8_TARGET_ARCH_IA32
     10 #include "src/crankshaft/ia32/lithium-ia32.h"  // NOLINT
     11 #include "src/crankshaft/ia32/lithium-codegen-ia32.h"  // NOLINT
     12 #elif V8_TARGET_ARCH_X64
     13 #include "src/crankshaft/x64/lithium-x64.h"  // NOLINT
     14 #include "src/crankshaft/x64/lithium-codegen-x64.h"  // NOLINT
     15 #elif V8_TARGET_ARCH_ARM
     16 #include "src/crankshaft/arm/lithium-arm.h"  // NOLINT
     17 #include "src/crankshaft/arm/lithium-codegen-arm.h"  // NOLINT
     18 #elif V8_TARGET_ARCH_PPC
     19 #include "src/crankshaft/ppc/lithium-ppc.h"          // NOLINT
     20 #include "src/crankshaft/ppc/lithium-codegen-ppc.h"  // NOLINT
     21 #elif V8_TARGET_ARCH_MIPS
     22 #include "src/crankshaft/mips/lithium-mips.h"  // NOLINT
     23 #include "src/crankshaft/mips/lithium-codegen-mips.h"  // NOLINT
     24 #elif V8_TARGET_ARCH_ARM64
     25 #include "src/crankshaft/arm64/lithium-arm64.h"  // NOLINT
     26 #include "src/crankshaft/arm64/lithium-codegen-arm64.h"  // NOLINT
     27 #elif V8_TARGET_ARCH_MIPS64
     28 #include "src/crankshaft/mips64/lithium-mips64.h"  // NOLINT
     29 #include "src/crankshaft/mips64/lithium-codegen-mips64.h"  // NOLINT
     30 #elif V8_TARGET_ARCH_X87
     31 #include "src/crankshaft/x87/lithium-x87.h"  // NOLINT
     32 #include "src/crankshaft/x87/lithium-codegen-x87.h"  // NOLINT
     33 #elif V8_TARGET_ARCH_S390
     34 #include "src/crankshaft/s390/lithium-s390.h"          // NOLINT
     35 #include "src/crankshaft/s390/lithium-codegen-s390.h"  // NOLINT
     36 #else
     37 #error "Unknown architecture."
     38 #endif
     39 
     40 namespace v8 {
     41 namespace internal {
     42 
     43 const auto GetRegConfig = RegisterConfiguration::Crankshaft;
     44 
     45 void LOperand::PrintTo(StringStream* stream) {
     46   LUnallocated* unalloc = NULL;
     47   switch (kind()) {
     48     case INVALID:
     49       stream->Add("(0)");
     50       break;
     51     case UNALLOCATED:
     52       unalloc = LUnallocated::cast(this);
     53       stream->Add("v%d", unalloc->virtual_register());
     54       if (unalloc->basic_policy() == LUnallocated::FIXED_SLOT) {
     55         stream->Add("(=%dS)", unalloc->fixed_slot_index());
     56         break;
     57       }
     58       switch (unalloc->extended_policy()) {
     59         case LUnallocated::NONE:
     60           break;
     61         case LUnallocated::FIXED_REGISTER: {
     62           int reg_index = unalloc->fixed_register_index();
     63           if (reg_index < 0 || reg_index >= Register::kNumRegisters) {
     64             stream->Add("(=invalid_reg#%d)", reg_index);
     65           } else {
     66             const char* register_name =
     67                 GetRegConfig()->GetGeneralRegisterName(reg_index);
     68             stream->Add("(=%s)", register_name);
     69           }
     70           break;
     71         }
     72         case LUnallocated::FIXED_DOUBLE_REGISTER: {
     73           int reg_index = unalloc->fixed_register_index();
     74           if (reg_index < 0 || reg_index >= DoubleRegister::kMaxNumRegisters) {
     75             stream->Add("(=invalid_double_reg#%d)", reg_index);
     76           } else {
     77             const char* double_register_name =
     78                 GetRegConfig()->GetDoubleRegisterName(reg_index);
     79             stream->Add("(=%s)", double_register_name);
     80           }
     81           break;
     82         }
     83         case LUnallocated::MUST_HAVE_REGISTER:
     84           stream->Add("(R)");
     85           break;
     86         case LUnallocated::MUST_HAVE_DOUBLE_REGISTER:
     87           stream->Add("(D)");
     88           break;
     89         case LUnallocated::WRITABLE_REGISTER:
     90           stream->Add("(WR)");
     91           break;
     92         case LUnallocated::SAME_AS_FIRST_INPUT:
     93           stream->Add("(1)");
     94           break;
     95         case LUnallocated::ANY:
     96           stream->Add("(-)");
     97           break;
     98       }
     99       break;
    100     case CONSTANT_OPERAND:
    101       stream->Add("[constant:%d]", index());
    102       break;
    103     case STACK_SLOT:
    104       stream->Add("[stack:%d]", index());
    105       break;
    106     case DOUBLE_STACK_SLOT:
    107       stream->Add("[double_stack:%d]", index());
    108       break;
    109     case REGISTER: {
    110       int reg_index = index();
    111       if (reg_index < 0 || reg_index >= Register::kNumRegisters) {
    112         stream->Add("(=invalid_reg#%d|R)", reg_index);
    113       } else {
    114         stream->Add("[%s|R]",
    115                     GetRegConfig()->GetGeneralRegisterName(reg_index));
    116       }
    117       break;
    118     }
    119     case DOUBLE_REGISTER: {
    120       int reg_index = index();
    121       if (reg_index < 0 || reg_index >= DoubleRegister::kMaxNumRegisters) {
    122         stream->Add("(=invalid_double_reg#%d|R)", reg_index);
    123       } else {
    124         stream->Add("[%s|R]", GetRegConfig()->GetDoubleRegisterName(reg_index));
    125       }
    126       break;
    127     }
    128   }
    129 }
    130 
    131 
    132 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
    133 LSubKindOperand<kOperandKind, kNumCachedOperands>*
    134 LSubKindOperand<kOperandKind, kNumCachedOperands>::cache = NULL;
    135 
    136 
    137 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
    138 void LSubKindOperand<kOperandKind, kNumCachedOperands>::SetUpCache() {
    139   if (cache) return;
    140   cache = new LSubKindOperand[kNumCachedOperands];
    141   for (int i = 0; i < kNumCachedOperands; i++) {
    142     cache[i].ConvertTo(kOperandKind, i);
    143   }
    144 }
    145 
    146 
    147 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
    148 void LSubKindOperand<kOperandKind, kNumCachedOperands>::TearDownCache() {
    149   delete[] cache;
    150   cache = NULL;
    151 }
    152 
    153 
    154 void LOperand::SetUpCaches() {
    155 #define LITHIUM_OPERAND_SETUP(name, type, number) L##name::SetUpCache();
    156   LITHIUM_OPERAND_LIST(LITHIUM_OPERAND_SETUP)
    157 #undef LITHIUM_OPERAND_SETUP
    158 }
    159 
    160 
    161 void LOperand::TearDownCaches() {
    162 #define LITHIUM_OPERAND_TEARDOWN(name, type, number) L##name::TearDownCache();
    163   LITHIUM_OPERAND_LIST(LITHIUM_OPERAND_TEARDOWN)
    164 #undef LITHIUM_OPERAND_TEARDOWN
    165 }
    166 
    167 
    168 bool LParallelMove::IsRedundant() const {
    169   for (int i = 0; i < move_operands_.length(); ++i) {
    170     if (!move_operands_[i].IsRedundant()) return false;
    171   }
    172   return true;
    173 }
    174 
    175 
    176 void LParallelMove::PrintDataTo(StringStream* stream) const {
    177   bool first = true;
    178   for (int i = 0; i < move_operands_.length(); ++i) {
    179     if (!move_operands_[i].IsEliminated()) {
    180       LOperand* source = move_operands_[i].source();
    181       LOperand* destination = move_operands_[i].destination();
    182       if (!first) stream->Add(" ");
    183       first = false;
    184       if (source->Equals(destination)) {
    185         destination->PrintTo(stream);
    186       } else {
    187         destination->PrintTo(stream);
    188         stream->Add(" = ");
    189         source->PrintTo(stream);
    190       }
    191       stream->Add(";");
    192     }
    193   }
    194 }
    195 
    196 
    197 void LEnvironment::PrintTo(StringStream* stream) {
    198   stream->Add("[id=%d|", ast_id().ToInt());
    199   if (deoptimization_index() != Safepoint::kNoDeoptimizationIndex) {
    200     stream->Add("deopt_id=%d|", deoptimization_index());
    201   }
    202   stream->Add("parameters=%d|", parameter_count());
    203   stream->Add("arguments_stack_height=%d|", arguments_stack_height());
    204   for (int i = 0; i < values_.length(); ++i) {
    205     if (i != 0) stream->Add(";");
    206     if (values_[i] == NULL) {
    207       stream->Add("[hole]");
    208     } else {
    209       values_[i]->PrintTo(stream);
    210     }
    211   }
    212   stream->Add("]");
    213 }
    214 
    215 
    216 void LPointerMap::RecordPointer(LOperand* op, Zone* zone) {
    217   // Do not record arguments as pointers.
    218   if (op->IsStackSlot() && op->index() < 0) return;
    219   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot());
    220   pointer_operands_.Add(op, zone);
    221 }
    222 
    223 
    224 void LPointerMap::RemovePointer(LOperand* op) {
    225   // Do not record arguments as pointers.
    226   if (op->IsStackSlot() && op->index() < 0) return;
    227   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot());
    228   for (int i = 0; i < pointer_operands_.length(); ++i) {
    229     if (pointer_operands_[i]->Equals(op)) {
    230       pointer_operands_.Remove(i);
    231       --i;
    232     }
    233   }
    234 }
    235 
    236 
    237 void LPointerMap::RecordUntagged(LOperand* op, Zone* zone) {
    238   // Do not record arguments as pointers.
    239   if (op->IsStackSlot() && op->index() < 0) return;
    240   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot());
    241   untagged_operands_.Add(op, zone);
    242 }
    243 
    244 
    245 void LPointerMap::PrintTo(StringStream* stream) {
    246   stream->Add("{");
    247   for (int i = 0; i < pointer_operands_.length(); ++i) {
    248     if (i != 0) stream->Add(";");
    249     pointer_operands_[i]->PrintTo(stream);
    250   }
    251   stream->Add("}");
    252 }
    253 
    254 LChunk::LChunk(CompilationInfo* info, HGraph* graph)
    255     : base_frame_slots_(info->IsStub()
    256                             ? TypedFrameConstants::kFixedSlotCount
    257                             : StandardFrameConstants::kFixedSlotCount),
    258       current_frame_slots_(base_frame_slots_),
    259       info_(info),
    260       graph_(graph),
    261       instructions_(32, info->zone()),
    262       pointer_maps_(8, info->zone()),
    263       inlined_functions_(1, info->zone()),
    264       deprecation_dependencies_(32, info->zone()),
    265       stability_dependencies_(8, info->zone()) {}
    266 
    267 LLabel* LChunk::GetLabel(int block_id) const {
    268   HBasicBlock* block = graph_->blocks()->at(block_id);
    269   int first_instruction = block->first_instruction_index();
    270   return LLabel::cast(instructions_[first_instruction]);
    271 }
    272 
    273 
    274 int LChunk::LookupDestination(int block_id) const {
    275   LLabel* cur = GetLabel(block_id);
    276   while (cur->replacement() != NULL) {
    277     cur = cur->replacement();
    278   }
    279   return cur->block_id();
    280 }
    281 
    282 Label* LChunk::GetAssemblyLabel(int block_id) const {
    283   LLabel* label = GetLabel(block_id);
    284   DCHECK(!label->HasReplacement());
    285   return label->label();
    286 }
    287 
    288 
    289 void LChunk::MarkEmptyBlocks() {
    290   LPhase phase("L_Mark empty blocks", this);
    291   for (int i = 0; i < graph()->blocks()->length(); ++i) {
    292     HBasicBlock* block = graph()->blocks()->at(i);
    293     int first = block->first_instruction_index();
    294     int last = block->last_instruction_index();
    295     LInstruction* first_instr = instructions()->at(first);
    296     LInstruction* last_instr = instructions()->at(last);
    297 
    298     LLabel* label = LLabel::cast(first_instr);
    299     if (last_instr->IsGoto()) {
    300       LGoto* goto_instr = LGoto::cast(last_instr);
    301       if (label->IsRedundant() &&
    302           !label->is_loop_header()) {
    303         bool can_eliminate = true;
    304         for (int i = first + 1; i < last && can_eliminate; ++i) {
    305           LInstruction* cur = instructions()->at(i);
    306           if (cur->IsGap()) {
    307             LGap* gap = LGap::cast(cur);
    308             if (!gap->IsRedundant()) {
    309               can_eliminate = false;
    310             }
    311           } else {
    312             can_eliminate = false;
    313           }
    314         }
    315         if (can_eliminate) {
    316           label->set_replacement(GetLabel(goto_instr->block_id()));
    317         }
    318       }
    319     }
    320   }
    321 }
    322 
    323 
    324 void LChunk::AddInstruction(LInstruction* instr, HBasicBlock* block) {
    325   LInstructionGap* gap = new (zone()) LInstructionGap(block);
    326   gap->set_hydrogen_value(instr->hydrogen_value());
    327   int index = -1;
    328   if (instr->IsControl()) {
    329     instructions_.Add(gap, zone());
    330     index = instructions_.length();
    331     instructions_.Add(instr, zone());
    332   } else {
    333     index = instructions_.length();
    334     instructions_.Add(instr, zone());
    335     instructions_.Add(gap, zone());
    336   }
    337   if (instr->HasPointerMap()) {
    338     pointer_maps_.Add(instr->pointer_map(), zone());
    339     instr->pointer_map()->set_lithium_position(index);
    340   }
    341 }
    342 
    343 LConstantOperand* LChunk::DefineConstantOperand(HConstant* constant) {
    344   return LConstantOperand::Create(constant->id(), zone());
    345 }
    346 
    347 
    348 int LChunk::GetParameterStackSlot(int index) const {
    349   // The receiver is at index 0, the first parameter at index 1, so we
    350   // shift all parameter indexes down by the number of parameters, and
    351   // make sure they end up negative so they are distinguishable from
    352   // spill slots.
    353   int result = index - info()->num_parameters() - 1;
    354 
    355   DCHECK(result < 0);
    356   return result;
    357 }
    358 
    359 
    360 // A parameter relative to ebp in the arguments stub.
    361 int LChunk::ParameterAt(int index) {
    362   DCHECK(-1 <= index);  // -1 is the receiver.
    363   return (1 + info()->scope()->num_parameters() - index) *
    364       kPointerSize;
    365 }
    366 
    367 
    368 LGap* LChunk::GetGapAt(int index) const {
    369   return LGap::cast(instructions_[index]);
    370 }
    371 
    372 
    373 bool LChunk::IsGapAt(int index) const {
    374   return instructions_[index]->IsGap();
    375 }
    376 
    377 
    378 int LChunk::NearestGapPos(int index) const {
    379   while (!IsGapAt(index)) index--;
    380   return index;
    381 }
    382 
    383 
    384 void LChunk::AddGapMove(int index, LOperand* from, LOperand* to) {
    385   GetGapAt(index)->GetOrCreateParallelMove(
    386       LGap::START, zone())->AddMove(from, to, zone());
    387 }
    388 
    389 
    390 HConstant* LChunk::LookupConstant(LConstantOperand* operand) const {
    391   return HConstant::cast(graph_->LookupValue(operand->index()));
    392 }
    393 
    394 
    395 Representation LChunk::LookupLiteralRepresentation(
    396     LConstantOperand* operand) const {
    397   return graph_->LookupValue(operand->index())->representation();
    398 }
    399 
    400 
    401 void LChunk::CommitDependencies(Handle<Code> code) const {
    402   if (!code->is_optimized_code()) return;
    403   HandleScope scope(isolate());
    404 
    405   for (Handle<Map> map : deprecation_dependencies_) {
    406     DCHECK(!map->is_deprecated());
    407     DCHECK(map->CanBeDeprecated());
    408     Map::AddDependentCode(map, DependentCode::kTransitionGroup, code);
    409   }
    410 
    411   for (Handle<Map> map : stability_dependencies_) {
    412     DCHECK(map->is_stable());
    413     DCHECK(map->CanTransition());
    414     Map::AddDependentCode(map, DependentCode::kPrototypeCheckGroup, code);
    415   }
    416 
    417   info_->dependencies()->Commit(code);
    418 }
    419 
    420 
    421 LChunk* LChunk::NewChunk(HGraph* graph) {
    422   DisallowHandleAllocation no_handles;
    423   DisallowHeapAllocation no_gc;
    424   graph->DisallowAddingNewValues();
    425   int values = graph->GetMaximumValueID();
    426   CompilationInfo* info = graph->info();
    427   if (values > LUnallocated::kMaxVirtualRegisters) {
    428     info->AbortOptimization(kNotEnoughVirtualRegistersForValues);
    429     return NULL;
    430   }
    431   LAllocator allocator(values, graph);
    432   LChunkBuilder builder(info, graph, &allocator);
    433   LChunk* chunk = builder.Build();
    434   if (chunk == NULL) return NULL;
    435 
    436   if (!allocator.Allocate(chunk)) {
    437     info->AbortOptimization(kNotEnoughVirtualRegistersRegalloc);
    438     return NULL;
    439   }
    440 
    441   chunk->set_allocated_double_registers(
    442       allocator.assigned_double_registers());
    443 
    444   return chunk;
    445 }
    446 
    447 
    448 Handle<Code> LChunk::Codegen() {
    449   MacroAssembler assembler(info()->isolate(), NULL, 0,
    450                            CodeObjectRequired::kYes);
    451   LOG_CODE_EVENT(info()->isolate(),
    452                  CodeStartLinePosInfoRecordEvent(
    453                      assembler.positions_recorder()));
    454   // Code serializer only takes unoptimized code.
    455   DCHECK(!info()->will_serialize());
    456   LCodeGen generator(this, &assembler, info());
    457 
    458   MarkEmptyBlocks();
    459 
    460   if (generator.GenerateCode()) {
    461     generator.CheckEnvironmentUsage();
    462     CodeGenerator::MakeCodePrologue(info(), "optimized");
    463     Handle<Code> code = CodeGenerator::MakeCodeEpilogue(&assembler, info());
    464     generator.FinishCode(code);
    465     CommitDependencies(code);
    466     code->set_is_crankshafted(true);
    467     void* jit_handler_data =
    468         assembler.positions_recorder()->DetachJITHandlerData();
    469     LOG_CODE_EVENT(info()->isolate(),
    470                    CodeEndLinePosInfoRecordEvent(AbstractCode::cast(*code),
    471                                                  jit_handler_data));
    472 
    473     CodeGenerator::PrintCode(code, info());
    474     DCHECK(!(info()->GetMustNotHaveEagerFrame() &&
    475              generator.NeedsEagerFrame()));
    476     return code;
    477   }
    478   assembler.AbortedCodeGeneration();
    479   return Handle<Code>::null();
    480 }
    481 
    482 
    483 void LChunk::set_allocated_double_registers(BitVector* allocated_registers) {
    484   allocated_double_registers_ = allocated_registers;
    485   BitVector* doubles = allocated_double_registers();
    486   BitVector::Iterator iterator(doubles);
    487   while (!iterator.Done()) {
    488     if (info()->saves_caller_doubles()) {
    489       if (kDoubleSize == kPointerSize * 2) {
    490         current_frame_slots_ += 2;
    491       } else {
    492         current_frame_slots_++;
    493       }
    494     }
    495     iterator.Advance();
    496   }
    497 }
    498 
    499 
    500 void LChunkBuilderBase::Abort(BailoutReason reason) {
    501   info()->AbortOptimization(reason);
    502   status_ = ABORTED;
    503 }
    504 
    505 
    506 void LChunkBuilderBase::Retry(BailoutReason reason) {
    507   info()->RetryOptimization(reason);
    508   status_ = ABORTED;
    509 }
    510 
    511 void LChunkBuilderBase::CreateLazyBailoutForCall(HBasicBlock* current_block,
    512                                                  LInstruction* instr,
    513                                                  HInstruction* hydrogen_val) {
    514   if (!instr->IsCall()) return;
    515 
    516   HEnvironment* hydrogen_env = current_block->last_environment();
    517   HValue* hydrogen_value_for_lazy_bailout = hydrogen_val;
    518   DCHECK_NOT_NULL(hydrogen_env);
    519   if (instr->IsSyntacticTailCall()) {
    520     // If it was a syntactic tail call we need to drop the current frame and
    521     // all the frames on top of it that are either an arguments adaptor frame
    522     // or a tail caller frame.
    523     hydrogen_env = hydrogen_env->outer();
    524     while (hydrogen_env != nullptr &&
    525            (hydrogen_env->frame_type() == ARGUMENTS_ADAPTOR ||
    526             hydrogen_env->frame_type() == TAIL_CALLER_FUNCTION)) {
    527       hydrogen_env = hydrogen_env->outer();
    528     }
    529     if (hydrogen_env != nullptr) {
    530       if (hydrogen_env->frame_type() == JS_FUNCTION) {
    531         // In case an outer frame is a function frame we have to replay
    532         // environment manually because
    533         // 1) it does not contain a result of inlined function yet,
    534         // 2) we can't find the proper simulate that corresponds to the point
    535         //    after inlined call to do a ReplayEnvironment() on.
    536         // So we push return value on top of outer environment.
    537         // As for JS_GETTER/JS_SETTER/JS_CONSTRUCT nothing has to be done here,
    538         // the deoptimizer ensures that the result of the callee is correctly
    539         // propagated to result register during deoptimization.
    540         hydrogen_env = hydrogen_env->Copy();
    541         hydrogen_env->Push(hydrogen_val);
    542       }
    543     } else {
    544       // Although we don't need this lazy bailout for normal execution
    545       // (because when we tail call from the outermost function we should pop
    546       // its frame) we still need it when debugger is on.
    547       hydrogen_env = current_block->last_environment();
    548     }
    549   } else {
    550     if (hydrogen_val->HasObservableSideEffects()) {
    551       HSimulate* sim = HSimulate::cast(hydrogen_val->next());
    552       sim->ReplayEnvironment(hydrogen_env);
    553       hydrogen_value_for_lazy_bailout = sim;
    554     }
    555   }
    556   LInstruction* bailout = LChunkBuilderBase::AssignEnvironment(
    557       new (zone()) LLazyBailout(), hydrogen_env);
    558   bailout->set_hydrogen_value(hydrogen_value_for_lazy_bailout);
    559   chunk_->AddInstruction(bailout, current_block);
    560 }
    561 
    562 LInstruction* LChunkBuilderBase::AssignEnvironment(LInstruction* instr,
    563                                                    HEnvironment* hydrogen_env) {
    564   int argument_index_accumulator = 0;
    565   ZoneList<HValue*> objects_to_materialize(0, zone());
    566   DCHECK_NE(TAIL_CALLER_FUNCTION, hydrogen_env->frame_type());
    567   instr->set_environment(CreateEnvironment(
    568       hydrogen_env, &argument_index_accumulator, &objects_to_materialize));
    569   return instr;
    570 }
    571 
    572 LEnvironment* LChunkBuilderBase::CreateEnvironment(
    573     HEnvironment* hydrogen_env, int* argument_index_accumulator,
    574     ZoneList<HValue*>* objects_to_materialize) {
    575   if (hydrogen_env == NULL) return NULL;
    576 
    577   BailoutId ast_id = hydrogen_env->ast_id();
    578   DCHECK(!ast_id.IsNone() ||
    579          (hydrogen_env->frame_type() != JS_FUNCTION &&
    580           hydrogen_env->frame_type() != TAIL_CALLER_FUNCTION));
    581 
    582   if (hydrogen_env->frame_type() == TAIL_CALLER_FUNCTION) {
    583     // Skip potential outer arguments adaptor frame.
    584     HEnvironment* outer_hydrogen_env = hydrogen_env->outer();
    585     if (outer_hydrogen_env != nullptr &&
    586         outer_hydrogen_env->frame_type() == ARGUMENTS_ADAPTOR) {
    587       outer_hydrogen_env = outer_hydrogen_env->outer();
    588     }
    589     LEnvironment* outer = CreateEnvironment(
    590         outer_hydrogen_env, argument_index_accumulator, objects_to_materialize);
    591     return new (zone())
    592         LEnvironment(hydrogen_env->closure(), hydrogen_env->frame_type(),
    593                      ast_id, 0, 0, 0, outer, hydrogen_env->entry(), zone());
    594   }
    595 
    596   LEnvironment* outer =
    597       CreateEnvironment(hydrogen_env->outer(), argument_index_accumulator,
    598                         objects_to_materialize);
    599 
    600   int omitted_count = (hydrogen_env->frame_type() == JS_FUNCTION)
    601                           ? 0
    602                           : hydrogen_env->specials_count();
    603 
    604   int value_count = hydrogen_env->length() - omitted_count;
    605   LEnvironment* result =
    606       new(zone()) LEnvironment(hydrogen_env->closure(),
    607                                hydrogen_env->frame_type(),
    608                                ast_id,
    609                                hydrogen_env->parameter_count(),
    610                                argument_count_,
    611                                value_count,
    612                                outer,
    613                                hydrogen_env->entry(),
    614                                zone());
    615   int argument_index = *argument_index_accumulator;
    616 
    617   // Store the environment description into the environment
    618   // (with holes for nested objects)
    619   for (int i = 0; i < hydrogen_env->length(); ++i) {
    620     if (hydrogen_env->is_special_index(i) &&
    621         hydrogen_env->frame_type() != JS_FUNCTION) {
    622       continue;
    623     }
    624     LOperand* op;
    625     HValue* value = hydrogen_env->values()->at(i);
    626     CHECK(!value->IsPushArguments());  // Do not deopt outgoing arguments
    627     if (value->IsArgumentsObject() || value->IsCapturedObject()) {
    628       op = LEnvironment::materialization_marker();
    629     } else {
    630       op = UseAny(value);
    631     }
    632     result->AddValue(op,
    633                      value->representation(),
    634                      value->CheckFlag(HInstruction::kUint32));
    635   }
    636 
    637   // Recursively store the nested objects into the environment
    638   for (int i = 0; i < hydrogen_env->length(); ++i) {
    639     if (hydrogen_env->is_special_index(i)) continue;
    640 
    641     HValue* value = hydrogen_env->values()->at(i);
    642     if (value->IsArgumentsObject() || value->IsCapturedObject()) {
    643       AddObjectToMaterialize(value, objects_to_materialize, result);
    644     }
    645   }
    646 
    647   if (hydrogen_env->frame_type() == JS_FUNCTION) {
    648     *argument_index_accumulator = argument_index;
    649   }
    650 
    651   return result;
    652 }
    653 
    654 
    655 // Add an object to the supplied environment and object materialization list.
    656 //
    657 // Notes:
    658 //
    659 // We are building three lists here:
    660 //
    661 // 1. In the result->object_mapping_ list (added to by the
    662 //    LEnvironment::Add*Object methods), we store the lengths (number
    663 //    of fields) of the captured objects in depth-first traversal order, or
    664 //    in case of duplicated objects, we store the index to the duplicate object
    665 //    (with a tag to differentiate between captured and duplicated objects).
    666 //
    667 // 2. The object fields are stored in the result->values_ list
    668 //    (added to by the LEnvironment.AddValue method) sequentially as lists
    669 //    of fields with holes for nested objects (the holes will be expanded
    670 //    later by LCodegen::AddToTranslation according to the
    671 //    LEnvironment.object_mapping_ list).
    672 //
    673 // 3. The auxiliary objects_to_materialize array stores the hydrogen values
    674 //    in the same order as result->object_mapping_ list. This is used
    675 //    to detect duplicate values and calculate the corresponding object index.
    676 void LChunkBuilderBase::AddObjectToMaterialize(HValue* value,
    677     ZoneList<HValue*>* objects_to_materialize, LEnvironment* result) {
    678   int object_index = objects_to_materialize->length();
    679   // Store the hydrogen value into the de-duplication array
    680   objects_to_materialize->Add(value, zone());
    681   // Find out whether we are storing a duplicated value
    682   int previously_materialized_object = -1;
    683   for (int prev = 0; prev < object_index; ++prev) {
    684     if (objects_to_materialize->at(prev) == value) {
    685       previously_materialized_object = prev;
    686       break;
    687     }
    688   }
    689   // Store the captured object length (or duplicated object index)
    690   // into the environment. For duplicated objects, we stop here.
    691   int length = value->OperandCount();
    692   bool is_arguments = value->IsArgumentsObject();
    693   if (previously_materialized_object >= 0) {
    694     result->AddDuplicateObject(previously_materialized_object);
    695     return;
    696   } else {
    697     result->AddNewObject(is_arguments ? length - 1 : length, is_arguments);
    698   }
    699   // Store the captured object's fields into the environment
    700   for (int i = is_arguments ? 1 : 0; i < length; ++i) {
    701     LOperand* op;
    702     HValue* arg_value = value->OperandAt(i);
    703     if (arg_value->IsArgumentsObject() || arg_value->IsCapturedObject()) {
    704       // Insert a hole for nested objects
    705       op = LEnvironment::materialization_marker();
    706     } else {
    707       DCHECK(!arg_value->IsPushArguments());
    708       // For ordinary values, tell the register allocator we need the value
    709       // to be alive here
    710       op = UseAny(arg_value);
    711     }
    712     result->AddValue(op,
    713                      arg_value->representation(),
    714                      arg_value->CheckFlag(HInstruction::kUint32));
    715   }
    716   // Recursively store all the nested captured objects into the environment
    717   for (int i = is_arguments ? 1 : 0; i < length; ++i) {
    718     HValue* arg_value = value->OperandAt(i);
    719     if (arg_value->IsArgumentsObject() || arg_value->IsCapturedObject()) {
    720       AddObjectToMaterialize(arg_value, objects_to_materialize, result);
    721     }
    722   }
    723 }
    724 
    725 
    726 LPhase::~LPhase() {
    727   if (ShouldProduceTraceOutput()) {
    728     isolate()->GetHTracer()->TraceLithium(name(), chunk_);
    729   }
    730 }
    731 
    732 
    733 }  // namespace internal
    734 }  // namespace v8
    735