src/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/v8.h"
   6
   7 #include "src/lithium.h"
   8 #include "src/scopes.h"
   9 #include "src/serialize.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_MIPS
  21 #include "src/mips/lithium-mips.h"  // NOLINT
  22 #include "src/mips/lithium-codegen-mips.h"  // NOLINT
  23 #elif V8_TARGET_ARCH_ARM64
  24 #include "src/arm64/lithium-arm64.h"  // NOLINT
  25 #include "src/arm64/lithium-codegen-arm64.h"  // NOLINT
  26 #elif V8_TARGET_ARCH_MIPS64
  27 #include "src/mips64/lithium-mips64.h"  // NOLINT
  28 #include "src/mips64/lithium-codegen-mips64.h"  // NOLINT
  29 #elif V8_TARGET_ARCH_X87
  30 #include "src/x87/lithium-x87.h"  // NOLINT
  31 #include "src/x87/lithium-codegen-x87.h"  // NOLINT
  32 #else
  33 #error "Unknown architecture."
  34 #endif
  35
  36 namespace v8 {
  37 namespace internal {
  38
  39
  40 void LOperand::PrintTo(StringStream* stream) {
  41   LUnallocated* unalloc = NULL;
  42   switch (kind()) {
  43     case INVALID:
  44       stream->Add("(0)");
  45       break;
  46     case UNALLOCATED:
  47       unalloc = LUnallocated::cast(this);
  48       stream->Add("v%d", unalloc->virtual_register());
  49       if (unalloc->basic_policy() == LUnallocated::FIXED_SLOT) {
  50         stream->Add("(=%dS)", unalloc->fixed_slot_index());
  51         break;
  52       }
  53       switch (unalloc->extended_policy()) {
  54         case LUnallocated::NONE:
  55           break;
  56         case LUnallocated::FIXED_REGISTER: {
  57           int reg_index = unalloc->fixed_register_index();
  58           if (reg_index < 0 ||
  59               reg_index >= Register::kMaxNumAllocatableRegisters) {
  60             stream->Add("(=invalid_reg#%d)", reg_index);
  61           } else {
  62             const char* register_name =
  63                 Register::AllocationIndexToString(reg_index);
  64             stream->Add("(=%s)", register_name);
  65           }
  66           break;
  67         }
  68         case LUnallocated::FIXED_DOUBLE_REGISTER: {
  69           int reg_index = unalloc->fixed_register_index();
  70           if (reg_index < 0 ||
  71               reg_index >= DoubleRegister::kMaxNumAllocatableRegisters) {
  72             stream->Add("(=invalid_double_reg#%d)", reg_index);
  73           } else {
  74             const char* double_register_name =
  75                 DoubleRegister::AllocationIndexToString(reg_index);
  76             stream->Add("(=%s)", double_register_name);
  77           }
  78           break;
  79         }
  80         case LUnallocated::MUST_HAVE_REGISTER:
  81           stream->Add("(R)");
  82           break;
  83         case LUnallocated::MUST_HAVE_DOUBLE_REGISTER:
  84           stream->Add("(D)");
  85           break;
  86         case LUnallocated::WRITABLE_REGISTER:
  87           stream->Add("(WR)");
  88           break;
  89         case LUnallocated::SAME_AS_FIRST_INPUT:
  90           stream->Add("(1)");
  91           break;
  92         case LUnallocated::ANY:
  93           stream->Add("(-)");
  94           break;
  95       }
  96       break;
  97     case CONSTANT_OPERAND:
  98       stream->Add("[constant:%d]", index());
  99       break;
 100     case STACK_SLOT:
 101       stream->Add("[stack:%d]", index());
 102       break;
 103     case DOUBLE_STACK_SLOT:
 104       stream->Add("[double_stack:%d]", index());
 105       break;
 106     case REGISTER: {
 107       int reg_index = index();
 108       if (reg_index < 0 || reg_index >= Register::kMaxNumAllocatableRegisters) {
 109         stream->Add("(=invalid_reg#%d|R)", reg_index);
 110       } else {
 111         stream->Add("[%s|R]", Register::AllocationIndexToString(reg_index));
 112       }
 113       break;
 114     }
 115     case FLOAT32x4_STACK_SLOT:
 116       stream->Add("[float32x4_stack:%d]", index());
 117       break;
 118     case FLOAT64x2_STACK_SLOT:
 119       stream->Add("[float64x2_stack:%d]", index());
 120       break;
 121     case INT32x4_STACK_SLOT:
 122       stream->Add("[int32x4_stack:%d]", index());
 123       break;
 124     case DOUBLE_REGISTER: {
 125       int reg_index = index();
 126       if (reg_index < 0 ||
 127           reg_index >= DoubleRegister::kMaxNumAllocatableRegisters) {
 128         stream->Add("(=invalid_double_reg#%d|R)", reg_index);
 129       } else {
 130         stream->Add("[%s|R]",
 131                     DoubleRegister::AllocationIndexToString(reg_index));
 132       }
 133       break;
 134     }
 135     case FLOAT32x4_REGISTER:
 136       stream->Add("[%s|R]",
 137                   SIMD128Register::AllocationIndexToString(index()));
 138       break;
 139     case FLOAT64x2_REGISTER:
 140       stream->Add("[%s|R]",
 141                   SIMD128Register::AllocationIndexToString(index()));
 142       break;
 143     case INT32x4_REGISTER:
 144       stream->Add("[%s|R]",
 145                   SIMD128Register::AllocationIndexToString(index()));
 146       break;
 147   }
 148 }
 149
 150
 151 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
 152 LSubKindOperand<kOperandKind, kNumCachedOperands>*
 153 LSubKindOperand<kOperandKind, kNumCachedOperands>::cache = NULL;
 154
 155
 156 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
 157 void LSubKindOperand<kOperandKind, kNumCachedOperands>::SetUpCache() {
 158   if (cache) return;
 159   cache = new LSubKindOperand[kNumCachedOperands];
 160   for (int i = 0; i < kNumCachedOperands; i++) {
 161     cache[i].ConvertTo(kOperandKind, i);
 162   }
 163 }
 164
 165
 166 template<LOperand::Kind kOperandKind, int kNumCachedOperands>
 167 void LSubKindOperand<kOperandKind, kNumCachedOperands>::TearDownCache() {
 168   delete[] cache;
 169 }
 170
 171
 172 void LOperand::SetUpCaches() {
 173 #define LITHIUM_OPERAND_SETUP(name, type, number) L##name::SetUpCache();
 174   LITHIUM_OPERAND_LIST(LITHIUM_OPERAND_SETUP)
 175 #undef LITHIUM_OPERAND_SETUP
 176 }
 177
 178
 179 void LOperand::TearDownCaches() {
 180 #define LITHIUM_OPERAND_TEARDOWN(name, type, number) L##name::TearDownCache();
 181   LITHIUM_OPERAND_LIST(LITHIUM_OPERAND_TEARDOWN)
 182 #undef LITHIUM_OPERAND_TEARDOWN
 183 }
 184
 185
 186 bool LParallelMove::IsRedundant() const {
 187   for (int i = 0; i < move_operands_.length(); ++i) {
 188     if (!move_operands_[i].IsRedundant()) return false;
 189   }
 190   return true;
 191 }
 192
 193
 194 void LParallelMove::PrintDataTo(StringStream* stream) const {
 195   bool first = true;
 196   for (int i = 0; i < move_operands_.length(); ++i) {
 197     if (!move_operands_[i].IsEliminated()) {
 198       LOperand* source = move_operands_[i].source();
 199       LOperand* destination = move_operands_[i].destination();
 200       if (!first) stream->Add(" ");
 201       first = false;
 202       if (source->Equals(destination)) {
 203         destination->PrintTo(stream);
 204       } else {
 205         destination->PrintTo(stream);
 206         stream->Add(" = ");
 207         source->PrintTo(stream);
 208       }
 209       stream->Add(";");
 210     }
 211   }
 212 }
 213
 214
 215 void LEnvironment::PrintTo(StringStream* stream) {
 216   stream->Add("[id=%d|", ast_id().ToInt());
 217   if (deoptimization_index() != Safepoint::kNoDeoptimizationIndex) {
 218     stream->Add("deopt_id=%d|", deoptimization_index());
 219   }
 220   stream->Add("parameters=%d|", parameter_count());
 221   stream->Add("arguments_stack_height=%d|", arguments_stack_height());
 222   for (int i = 0; i < values_.length(); ++i) {
 223     if (i != 0) stream->Add(";");
 224     if (values_[i] == NULL) {
 225       stream->Add("[hole]");
 226     } else {
 227       values_[i]->PrintTo(stream);
 228     }
 229   }
 230   stream->Add("]");
 231 }
 232
 233
 234 void LPointerMap::RecordPointer(LOperand* op, Zone* zone) {
 235   // Do not record arguments as pointers.
 236   if (op->IsStackSlot() && op->index() < 0) return;
 237   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot() &&
 238          !op->IsFloat32x4Register() && !op->IsFloat32x4StackSlot() &&
 239          !op->IsFloat64x2Register() && !op->IsFloat64x2StackSlot() &&
 240          !op->IsInt32x4Register() && !op->IsInt32x4StackSlot());
 241   pointer_operands_.Add(op, zone);
 242 }
 243
 244
 245 void LPointerMap::RemovePointer(LOperand* op) {
 246   // Do not record arguments as pointers.
 247   if (op->IsStackSlot() && op->index() < 0) return;
 248   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot() &&
 249          !op->IsFloat32x4Register() && !op->IsFloat32x4StackSlot() &&
 250          !op->IsFloat64x2Register() && !op->IsFloat64x2StackSlot() &&
 251          !op->IsInt32x4Register() && !op->IsInt32x4StackSlot());
 252   for (int i = 0; i < pointer_operands_.length(); ++i) {
 253     if (pointer_operands_[i]->Equals(op)) {
 254       pointer_operands_.Remove(i);
 255       --i;
 256     }
 257   }
 258 }
 259
 260
 261 void LPointerMap::RecordUntagged(LOperand* op, Zone* zone) {
 262   // Do not record arguments as pointers.
 263   if (op->IsStackSlot() && op->index() < 0) return;
 264   DCHECK(!op->IsDoubleRegister() && !op->IsDoubleStackSlot() &&
 265          !op->IsFloat32x4Register() && !op->IsFloat32x4StackSlot() &&
 266          !op->IsFloat64x2Register() && !op->IsFloat64x2StackSlot() &&
 267          !op->IsInt32x4Register() && !op->IsInt32x4StackSlot());
 268   untagged_operands_.Add(op, zone);
 269 }
 270
 271
 272 void LPointerMap::PrintTo(StringStream* stream) {
 273   stream->Add("{");
 274   for (int i = 0; i < pointer_operands_.length(); ++i) {
 275     if (i != 0) stream->Add(";");
 276     pointer_operands_[i]->PrintTo(stream);
 277   }
 278   stream->Add("}");
 279 }
 280
 281
 282 int StackSlotOffset(int index) {
 283   if (index >= 0) {
 284     // Local or spill slot. Skip the frame pointer, function, and
 285     // context in the fixed part of the frame.
 286     return -(index + 1) * kPointerSize -
 287         StandardFrameConstants::kFixedFrameSizeFromFp;
 288   } else {
 289     // Incoming parameter. Skip the return address.
 290     return -(index + 1) * kPointerSize + kFPOnStackSize + kPCOnStackSize;
 291   }
 292 }
 293
 294
 295 LChunk::LChunk(CompilationInfo* info, HGraph* graph)
 296     : spill_slot_count_(0),
 297       info_(info),
 298       graph_(graph),
 299       instructions_(32, info->zone()),
 300       pointer_maps_(8, info->zone()),
 301       inlined_closures_(1, info->zone()),
 302       deprecation_dependencies_(MapLess(), MapAllocator(info->zone())),
 303       stability_dependencies_(MapLess(), MapAllocator(info->zone())) {}
 304
 305
 306 LLabel* LChunk::GetLabel(int block_id) const {
 307   HBasicBlock* block = graph_->blocks()->at(block_id);
 308   int first_instruction = block->first_instruction_index();
 309   return LLabel::cast(instructions_[first_instruction]);
 310 }
 311
 312
 313 int LChunk::LookupDestination(int block_id) const {
 314   LLabel* cur = GetLabel(block_id);
 315   while (cur->replacement() != NULL) {
 316     cur = cur->replacement();
 317   }
 318   return cur->block_id();
 319 }
 320
 321 Label* LChunk::GetAssemblyLabel(int block_id) const {
 322   LLabel* label = GetLabel(block_id);
 323   DCHECK(!label->HasReplacement());
 324   return label->label();
 325 }
 326
 327
 328 void LChunk::MarkEmptyBlocks() {
 329   LPhase phase("L_Mark empty blocks", this);
 330   for (int i = 0; i < graph()->blocks()->length(); ++i) {
 331     HBasicBlock* block = graph()->blocks()->at(i);
 332     int first = block->first_instruction_index();
 333     int last = block->last_instruction_index();
 334     LInstruction* first_instr = instructions()->at(first);
 335     LInstruction* last_instr = instructions()->at(last);
 336
 337     LLabel* label = LLabel::cast(first_instr);
 338     if (last_instr->IsGoto()) {
 339       LGoto* goto_instr = LGoto::cast(last_instr);
 340       if (label->IsRedundant() &&
 341           !label->is_loop_header()) {
 342         bool can_eliminate = true;
 343         for (int i = first + 1; i < last && can_eliminate; ++i) {
 344           LInstruction* cur = instructions()->at(i);
 345           if (cur->IsGap()) {
 346             LGap* gap = LGap::cast(cur);
 347             if (!gap->IsRedundant()) {
 348               can_eliminate = false;
 349             }
 350           } else {
 351             can_eliminate = false;
 352           }
 353         }
 354         if (can_eliminate) {
 355           label->set_replacement(GetLabel(goto_instr->block_id()));
 356         }
 357       }
 358     }
 359   }
 360 }
 361
 362
 363 void LChunk::AddInstruction(LInstruction* instr, HBasicBlock* block) {
 364   LInstructionGap* gap = new (zone()) LInstructionGap(block);
 365   gap->set_hydrogen_value(instr->hydrogen_value());
 366   int index = -1;
 367   if (instr->IsControl()) {
 368     instructions_.Add(gap, zone());
 369     index = instructions_.length();
 370     instructions_.Add(instr, zone());
 371   } else {
 372     index = instructions_.length();
 373     instructions_.Add(instr, zone());
 374     instructions_.Add(gap, zone());
 375   }
 376   if (instr->HasPointerMap()) {
 377     pointer_maps_.Add(instr->pointer_map(), zone());
 378     instr->pointer_map()->set_lithium_position(index);
 379   }
 380 }
 381
 382
 383 LConstantOperand* LChunk::DefineConstantOperand(HConstant* constant) {
 384   return LConstantOperand::Create(constant->id(), zone());
 385 }
 386
 387
 388 int LChunk::GetParameterStackSlot(int index) const {
 389   // The receiver is at index 0, the first parameter at index 1, so we
 390   // shift all parameter indexes down by the number of parameters, and
 391   // make sure they end up negative so they are distinguishable from
 392   // spill slots.
 393   int result = index - info()->num_parameters() - 1;
 394
 395   DCHECK(result < 0);
 396   return result;
 397 }
 398
 399
 400 // A parameter relative to ebp in the arguments stub.
 401 int LChunk::ParameterAt(int index) {
 402   DCHECK(-1 <= index);  // -1 is the receiver.
 403   return (1 + info()->scope()->num_parameters() - index) *
 404       kPointerSize;
 405 }
 406
 407
 408 LGap* LChunk::GetGapAt(int index) const {
 409   return LGap::cast(instructions_[index]);
 410 }
 411
 412
 413 bool LChunk::IsGapAt(int index) const {
 414   return instructions_[index]->IsGap();
 415 }
 416
 417
 418 int LChunk::NearestGapPos(int index) const {
 419   while (!IsGapAt(index)) index--;
 420   return index;
 421 }
 422
 423
 424 void LChunk::AddGapMove(int index, LOperand* from, LOperand* to) {
 425   GetGapAt(index)->GetOrCreateParallelMove(
 426       LGap::START, zone())->AddMove(from, to, zone());
 427 }
 428
 429
 430 HConstant* LChunk::LookupConstant(LConstantOperand* operand) const {
 431   return HConstant::cast(graph_->LookupValue(operand->index()));
 432 }
 433
 434
 435 Representation LChunk::LookupLiteralRepresentation(
 436     LConstantOperand* operand) const {
 437   return graph_->LookupValue(operand->index())->representation();
 438 }
 439
 440
 441 void LChunk::CommitDependencies(Handle<Code> code) const {
 442   for (MapSet::const_iterator it = deprecation_dependencies_.begin(),
 443        iend = deprecation_dependencies_.end(); it != iend; ++it) {
 444     Handle<Map> map = *it;
 445     DCHECK(!map->is_deprecated());
 446     DCHECK(map->CanBeDeprecated());
 447     Map::AddDependentCode(map, DependentCode::kTransitionGroup, code);
 448   }
 449
 450   for (MapSet::const_iterator it = stability_dependencies_.begin(),
 451        iend = stability_dependencies_.end(); it != iend; ++it) {
 452     Handle<Map> map = *it;
 453     DCHECK(map->is_stable());
 454     DCHECK(map->CanTransition());
 455     Map::AddDependentCode(map, DependentCode::kPrototypeCheckGroup, code);
 456   }
 457
 458   info_->CommitDependencies(code);
 459 }
 460
 461
 462 LChunk* LChunk::NewChunk(HGraph* graph) {
 463   DisallowHandleAllocation no_handles;
 464   DisallowHeapAllocation no_gc;
 465   graph->DisallowAddingNewValues();
 466   int values = graph->GetMaximumValueID();
 467   CompilationInfo* info = graph->info();
 468   if (values > LUnallocated::kMaxVirtualRegisters) {
 469     info->set_bailout_reason(kNotEnoughVirtualRegistersForValues);
 470     return NULL;
 471   }
 472   LAllocator allocator(values, graph);
 473   LChunkBuilder builder(info, graph, &allocator);
 474   LChunk* chunk = builder.Build();
 475   if (chunk == NULL) return NULL;
 476
 477   if (!allocator.Allocate(chunk)) {
 478     info->set_bailout_reason(kNotEnoughVirtualRegistersRegalloc);
 479     return NULL;
 480   }
 481
 482   chunk->set_allocated_double_registers(
 483       allocator.assigned_double_registers());
 484
 485   return chunk;
 486 }
 487
 488
 489 Handle<Code> LChunk::Codegen() {
 490   MacroAssembler assembler(info()->isolate(), NULL, 0);
 491   LOG_CODE_EVENT(info()->isolate(),
 492                  CodeStartLinePosInfoRecordEvent(
 493                      assembler.positions_recorder()));
 494   // TODO(yangguo) remove this once the code serializer handles code stubs.
 495   if (info()->will_serialize()) assembler.enable_serializer();
 496   LCodeGen generator(this, &assembler, info());
 497
 498   MarkEmptyBlocks();
 499
 500   if (generator.GenerateCode()) {
 501     generator.CheckEnvironmentUsage();
 502     CodeGenerator::MakeCodePrologue(info(), "optimized");
 503     Code::Flags flags = info()->flags();
 504     Handle<Code> code =
 505         CodeGenerator::MakeCodeEpilogue(&assembler, flags, info());
 506     generator.FinishCode(code);
 507     CommitDependencies(code);
 508     code->set_is_crankshafted(true);
 509     void* jit_handler_data =
 510         assembler.positions_recorder()->DetachJITHandlerData();
 511     LOG_CODE_EVENT(info()->isolate(),
 512                    CodeEndLinePosInfoRecordEvent(*code, jit_handler_data));
 513
 514     CodeGenerator::PrintCode(code, info());
 515     DCHECK(!(info()->isolate()->serializer_enabled() &&
 516              info()->GetMustNotHaveEagerFrame() &&
 517              generator.NeedsEagerFrame()));
 518     return code;
 519   }
 520   assembler.AbortedCodeGeneration();
 521   return Handle<Code>::null();
 522 }
 523
 524
 525 void LChunk::set_allocated_double_registers(BitVector* allocated_registers) {
 526   allocated_double_registers_ = allocated_registers;
 527   BitVector* doubles = allocated_double_registers();
 528   BitVector::Iterator iterator(doubles);
 529   while (!iterator.Done()) {
 530     if (info()->saves_caller_doubles()) {
 531       if (kDoubleSize == kPointerSize * 2) {
 532         spill_slot_count_ += 2;
 533       } else {
 534         spill_slot_count_++;
 535       }
 536     }
 537     iterator.Advance();
 538   }
 539 }
 540
 541
 542 LEnvironment* LChunkBuilderBase::CreateEnvironment(
 543     HEnvironment* hydrogen_env,
 544     int* argument_index_accumulator,
 545     ZoneList<HValue*>* objects_to_materialize) {
 546   if (hydrogen_env == NULL) return NULL;
 547
 548   LEnvironment* outer = CreateEnvironment(hydrogen_env->outer(),
 549                                           argument_index_accumulator,
 550                                           objects_to_materialize);
 551   BailoutId ast_id = hydrogen_env->ast_id();
 552   DCHECK(!ast_id.IsNone() ||
 553          hydrogen_env->frame_type() != JS_FUNCTION);
 554   int value_count = hydrogen_env->length() - hydrogen_env->specials_count();
 555   LEnvironment* result =
 556       new(zone()) LEnvironment(hydrogen_env->closure(),
 557                                hydrogen_env->frame_type(),
 558                                ast_id,
 559                                hydrogen_env->parameter_count(),
 560                                argument_count_,
 561                                value_count,
 562                                outer,
 563                                hydrogen_env->entry(),
 564                                zone());
 565   int argument_index = *argument_index_accumulator;
 566
 567   // Store the environment description into the environment
 568   // (with holes for nested objects)
 569   for (int i = 0; i < hydrogen_env->length(); ++i) {
 570     if (hydrogen_env->is_special_index(i)) continue;
 571
 572     LOperand* op;
 573     HValue* value = hydrogen_env->values()->at(i);
 574     CHECK(!value->IsPushArguments());  // Do not deopt outgoing arguments
 575     if (value->IsArgumentsObject() || value->IsCapturedObject()) {
 576       op = LEnvironment::materialization_marker();
 577     } else {
 578       op = UseAny(value);
 579     }
 580     result->AddValue(op,
 581                      value->representation(),
 582                      value->CheckFlag(HInstruction::kUint32));
 583   }
 584
 585   // Recursively store the nested objects into the environment
 586   for (int i = 0; i < hydrogen_env->length(); ++i) {
 587     if (hydrogen_env->is_special_index(i)) continue;
 588
 589     HValue* value = hydrogen_env->values()->at(i);
 590     if (value->IsArgumentsObject() || value->IsCapturedObject()) {
 591       AddObjectToMaterialize(value, objects_to_materialize, result);
 592     }
 593   }
 594
 595   if (hydrogen_env->frame_type() == JS_FUNCTION) {
 596     *argument_index_accumulator = argument_index;
 597   }
 598
 599   return result;
 600 }
 601
 602
 603 // Add an object to the supplied environment and object materialization list.
 604 //
 605 // Notes:
 606 //
 607 // We are building three lists here:
 608 //
 609 // 1. In the result->object_mapping_ list (added to by the
 610 //    LEnvironment::Add*Object methods), we store the lengths (number
 611 //    of fields) of the captured objects in depth-first traversal order, or
 612 //    in case of duplicated objects, we store the index to the duplicate object
 613 //    (with a tag to differentiate between captured and duplicated objects).
 614 //
 615 // 2. The object fields are stored in the result->values_ list
 616 //    (added to by the LEnvironment.AddValue method) sequentially as lists
 617 //    of fields with holes for nested objects (the holes will be expanded
 618 //    later by LCodegen::AddToTranslation according to the
 619 //    LEnvironment.object_mapping_ list).
 620 //
 621 // 3. The auxiliary objects_to_materialize array stores the hydrogen values
 622 //    in the same order as result->object_mapping_ list. This is used
 623 //    to detect duplicate values and calculate the corresponding object index.
 624 void LChunkBuilderBase::AddObjectToMaterialize(HValue* value,
 625     ZoneList<HValue*>* objects_to_materialize, LEnvironment* result) {
 626   int object_index = objects_to_materialize->length();
 627   // Store the hydrogen value into the de-duplication array
 628   objects_to_materialize->Add(value, zone());
 629   // Find out whether we are storing a duplicated value
 630   int previously_materialized_object = -1;
 631   for (int prev = 0; prev < object_index; ++prev) {
 632     if (objects_to_materialize->at(prev) == value) {
 633       previously_materialized_object = prev;
 634       break;
 635     }
 636   }
 637   // Store the captured object length (or duplicated object index)
 638   // into the environment. For duplicated objects, we stop here.
 639   int length = value->OperandCount();
 640   bool is_arguments = value->IsArgumentsObject();
 641   if (previously_materialized_object >= 0) {
 642     result->AddDuplicateObject(previously_materialized_object);
 643     return;
 644   } else {
 645     result->AddNewObject(is_arguments ? length - 1 : length, is_arguments);
 646   }
 647   // Store the captured object's fields into the environment
 648   for (int i = is_arguments ? 1 : 0; i < length; ++i) {
 649     LOperand* op;
 650     HValue* arg_value = value->OperandAt(i);
 651     if (arg_value->IsArgumentsObject() || arg_value->IsCapturedObject()) {
 652       // Insert a hole for nested objects
 653       op = LEnvironment::materialization_marker();
 654     } else {
 655       DCHECK(!arg_value->IsPushArguments());
 656       // For ordinary values, tell the register allocator we need the value
 657       // to be alive here
 658       op = UseAny(arg_value);
 659     }
 660     result->AddValue(op,
 661                      arg_value->representation(),
 662                      arg_value->CheckFlag(HInstruction::kUint32));
 663   }
 664   // Recursively store all the nested captured objects into the environment
 665   for (int i = is_arguments ? 1 : 0; i < length; ++i) {
 666     HValue* arg_value = value->OperandAt(i);
 667     if (arg_value->IsArgumentsObject() || arg_value->IsCapturedObject()) {
 668       AddObjectToMaterialize(arg_value, objects_to_materialize, result);
 669     }
 670   }
 671 }
 672
 673
 674 LPhase::~LPhase() {
 675   if (ShouldProduceTraceOutput()) {
 676     isolate()->GetHTracer()->TraceLithium(name(), chunk_);
 677   }
 678 }
 679
 680
 681 } }  // namespace v8::internal