deps/v8/src/lithium.cc

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