src/3rdparty/v8/src/heap-inl.h

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  27
  28 #ifndef V8_HEAP_INL_H_
  29 #define V8_HEAP_INL_H_
  30
  31 #include "heap.h"
  32 #include "isolate.h"
  33 #include "list-inl.h"
  34 #include "objects.h"
  35 #include "v8-counters.h"
  36 #include "store-buffer.h"
  37 #include "store-buffer-inl.h"
  38
  39 namespace v8 {
  40 namespace internal {
  41
  42 void PromotionQueue::insert(HeapObject* target, int size) {
  43   if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(rear_))) {
  44     NewSpacePage* rear_page =
  45         NewSpacePage::FromAddress(reinterpret_cast<Address>(rear_));
  46     ASSERT(!rear_page->prev_page()->is_anchor());
  47     rear_ = reinterpret_cast<intptr_t*>(rear_page->prev_page()->body_limit());
  48   }
  49   *(--rear_) = reinterpret_cast<intptr_t>(target);
  50   *(--rear_) = size;
  51   // Assert no overflow into live objects.
  52 #ifdef DEBUG
  53   SemiSpace::AssertValidRange(HEAP->new_space()->top(),
  54                               reinterpret_cast<Address>(rear_));
  55 #endif
  56 }
  57
  58
  59 int Heap::MaxObjectSizeInPagedSpace() {
  60   return Page::kMaxHeapObjectSize;
  61 }
  62
  63
  64 MaybeObject* Heap::AllocateStringFromUtf8(Vector<const char> str,
  65                                           PretenureFlag pretenure) {
  66   // Check for ASCII first since this is the common case.
  67   if (String::IsAscii(str.start(), str.length())) {
  68     // If the string is ASCII, we do not need to convert the characters
  69     // since UTF8 is backwards compatible with ASCII.
  70     return AllocateStringFromAscii(str, pretenure);
  71   }
  72   // Non-ASCII and we need to decode.
  73   return AllocateStringFromUtf8Slow(str, pretenure);
  74 }
  75
  76
  77 MaybeObject* Heap::AllocateSymbol(Vector<const char> str,
  78                                   int chars,
  79                                   uint32_t hash_field) {
  80   unibrow::Utf8InputBuffer<> buffer(str.start(),
  81                                     static_cast<unsigned>(str.length()));
  82   return AllocateInternalSymbol(&buffer, chars, hash_field);
  83 }
  84
  85
  86 MaybeObject* Heap::AllocateAsciiSymbol(Vector<const char> str,
  87                                        uint32_t hash_field) {
  88   if (str.length() > SeqAsciiString::kMaxLength) {
  89     return Failure::OutOfMemoryException();
  90   }
  91   // Compute map and object size.
  92   Map* map = ascii_symbol_map();
  93   int size = SeqAsciiString::SizeFor(str.length());
  94
  95   // Allocate string.
  96   Object* result;
  97   { MaybeObject* maybe_result = (size > MaxObjectSizeInPagedSpace())
  98                    ? lo_space_->AllocateRaw(size, NOT_EXECUTABLE)
  99                    : old_data_space_->AllocateRaw(size);
 100     if (!maybe_result->ToObject(&result)) return maybe_result;
 101   }
 102
 103   reinterpret_cast<HeapObject*>(result)->set_map(map);
 104   // Set length and hash fields of the allocated string.
 105   String* answer = String::cast(result);
 106   answer->set_length(str.length());
 107   answer->set_hash_field(hash_field);
 108   SeqString::cast(answer)->set_symbol_id(0);
 109
 110   ASSERT_EQ(size, answer->Size());
 111
 112   // Fill in the characters.
 113   memcpy(answer->address() + SeqAsciiString::kHeaderSize,
 114          str.start(), str.length());
 115
 116   return answer;
 117 }
 118
 119
 120 MaybeObject* Heap::AllocateTwoByteSymbol(Vector<const uc16> str,
 121                                          uint32_t hash_field) {
 122   if (str.length() > SeqTwoByteString::kMaxLength) {
 123     return Failure::OutOfMemoryException();
 124   }
 125   // Compute map and object size.
 126   Map* map = symbol_map();
 127   int size = SeqTwoByteString::SizeFor(str.length());
 128
 129   // Allocate string.
 130   Object* result;
 131   { MaybeObject* maybe_result = (size > MaxObjectSizeInPagedSpace())
 132                    ? lo_space_->AllocateRaw(size, NOT_EXECUTABLE)
 133                    : old_data_space_->AllocateRaw(size);
 134     if (!maybe_result->ToObject(&result)) return maybe_result;
 135   }
 136
 137   reinterpret_cast<HeapObject*>(result)->set_map(map);
 138   // Set length and hash fields of the allocated string.
 139   String* answer = String::cast(result);
 140   answer->set_length(str.length());
 141   answer->set_hash_field(hash_field);
 142   SeqString::cast(answer)->set_symbol_id(0);
 143
 144   ASSERT_EQ(size, answer->Size());
 145
 146   // Fill in the characters.
 147   memcpy(answer->address() + SeqTwoByteString::kHeaderSize,
 148          str.start(), str.length() * kUC16Size);
 149
 150   return answer;
 151 }
 152
 153 MaybeObject* Heap::CopyFixedArray(FixedArray* src) {
 154   return CopyFixedArrayWithMap(src, src->map());
 155 }
 156
 157
 158 MaybeObject* Heap::CopyFixedDoubleArray(FixedDoubleArray* src) {
 159   return CopyFixedDoubleArrayWithMap(src, src->map());
 160 }
 161
 162
 163 MaybeObject* Heap::AllocateRaw(int size_in_bytes,
 164                                AllocationSpace space,
 165                                AllocationSpace retry_space) {
 166   ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
 167   ASSERT(space != NEW_SPACE ||
 168          retry_space == OLD_POINTER_SPACE ||
 169          retry_space == OLD_DATA_SPACE ||
 170          retry_space == LO_SPACE);
 171 #ifdef DEBUG
 172   if (FLAG_gc_interval >= 0 &&
 173       !disallow_allocation_failure_ &&
 174       Heap::allocation_timeout_-- <= 0) {
 175     return Failure::RetryAfterGC(space);
 176   }
 177   isolate_->counters()->objs_since_last_full()->Increment();
 178   isolate_->counters()->objs_since_last_young()->Increment();
 179 #endif
 180   MaybeObject* result;
 181   if (NEW_SPACE == space) {
 182     result = new_space_.AllocateRaw(size_in_bytes);
 183     if (always_allocate() && result->IsFailure()) {
 184       space = retry_space;
 185     } else {
 186       return result;
 187     }
 188   }
 189
 190   if (OLD_POINTER_SPACE == space) {
 191     result = old_pointer_space_->AllocateRaw(size_in_bytes);
 192   } else if (OLD_DATA_SPACE == space) {
 193     result = old_data_space_->AllocateRaw(size_in_bytes);
 194   } else if (CODE_SPACE == space) {
 195     result = code_space_->AllocateRaw(size_in_bytes);
 196   } else if (LO_SPACE == space) {
 197     result = lo_space_->AllocateRaw(size_in_bytes, NOT_EXECUTABLE);
 198   } else if (CELL_SPACE == space) {
 199     result = cell_space_->AllocateRaw(size_in_bytes);
 200   } else {
 201     ASSERT(MAP_SPACE == space);
 202     result = map_space_->AllocateRaw(size_in_bytes);
 203   }
 204   if (result->IsFailure()) old_gen_exhausted_ = true;
 205   return result;
 206 }
 207
 208
 209 MaybeObject* Heap::NumberFromInt32(int32_t value) {
 210   if (Smi::IsValid(value)) return Smi::FromInt(value);
 211   // Bypass NumberFromDouble to avoid various redundant checks.
 212   return AllocateHeapNumber(FastI2D(value));
 213 }
 214
 215
 216 MaybeObject* Heap::NumberFromUint32(uint32_t value) {
 217   if ((int32_t)value >= 0 && Smi::IsValid((int32_t)value)) {
 218     return Smi::FromInt((int32_t)value);
 219   }
 220   // Bypass NumberFromDouble to avoid various redundant checks.
 221   return AllocateHeapNumber(FastUI2D(value));
 222 }
 223
 224
 225 void Heap::FinalizeExternalString(String* string) {
 226   ASSERT(string->IsExternalString());
 227   v8::String::ExternalStringResourceBase** resource_addr =
 228       reinterpret_cast<v8::String::ExternalStringResourceBase**>(
 229           reinterpret_cast<byte*>(string) +
 230           ExternalString::kResourceOffset -
 231           kHeapObjectTag);
 232
 233   // Dispose of the C++ object if it has not already been disposed.
 234   if (*resource_addr != NULL) {
 235     (*resource_addr)->Dispose();
 236   }
 237
 238   // Clear the resource pointer in the string.
 239   *resource_addr = NULL;
 240 }
 241
 242
 243 MaybeObject* Heap::AllocateRawMap() {
 244 #ifdef DEBUG
 245   isolate_->counters()->objs_since_last_full()->Increment();
 246   isolate_->counters()->objs_since_last_young()->Increment();
 247 #endif
 248   MaybeObject* result = map_space_->AllocateRaw(Map::kSize);
 249   if (result->IsFailure()) old_gen_exhausted_ = true;
 250 #ifdef DEBUG
 251   if (!result->IsFailure()) {
 252     // Maps have their own alignment.
 253     CHECK((reinterpret_cast<intptr_t>(result) & kMapAlignmentMask) ==
 254           static_cast<intptr_t>(kHeapObjectTag));
 255   }
 256 #endif
 257   return result;
 258 }
 259
 260
 261 MaybeObject* Heap::AllocateRawCell() {
 262 #ifdef DEBUG
 263   isolate_->counters()->objs_since_last_full()->Increment();
 264   isolate_->counters()->objs_since_last_young()->Increment();
 265 #endif
 266   MaybeObject* result = cell_space_->AllocateRaw(JSGlobalPropertyCell::kSize);
 267   if (result->IsFailure()) old_gen_exhausted_ = true;
 268   return result;
 269 }
 270
 271
 272 bool Heap::InNewSpace(Object* object) {
 273   bool result = new_space_.Contains(object);
 274   ASSERT(!result ||                  // Either not in new space
 275          gc_state_ != NOT_IN_GC ||   // ... or in the middle of GC
 276          InToSpace(object));         // ... or in to-space (where we allocate).
 277   return result;
 278 }
 279
 280
 281 bool Heap::InNewSpace(Address addr) {
 282   return new_space_.Contains(addr);
 283 }
 284
 285
 286 bool Heap::InFromSpace(Object* object) {
 287   return new_space_.FromSpaceContains(object);
 288 }
 289
 290
 291 bool Heap::InToSpace(Object* object) {
 292   return new_space_.ToSpaceContains(object);
 293 }
 294
 295
 296 bool Heap::OldGenerationAllocationLimitReached() {
 297   if (!incremental_marking()->IsStopped()) return false;
 298   return OldGenerationSpaceAvailable() < 0;
 299 }
 300
 301
 302 bool Heap::ShouldBePromoted(Address old_address, int object_size) {
 303   // An object should be promoted if:
 304   // - the object has survived a scavenge operation or
 305   // - to space is already 25% full.
 306   NewSpacePage* page = NewSpacePage::FromAddress(old_address);
 307   Address age_mark = new_space_.age_mark();
 308   bool below_mark = page->IsFlagSet(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK) &&
 309       (!page->ContainsLimit(age_mark) || old_address < age_mark);
 310   return below_mark || (new_space_.Size() + object_size) >=
 311                         (new_space_.EffectiveCapacity() >> 2);
 312 }
 313
 314
 315 void Heap::RecordWrite(Address address, int offset) {
 316   if (!InNewSpace(address)) store_buffer_.Mark(address + offset);
 317 }
 318
 319
 320 void Heap::RecordWrites(Address address, int start, int len) {
 321   if (!InNewSpace(address)) {
 322     for (int i = 0; i < len; i++) {
 323       store_buffer_.Mark(address + start + i * kPointerSize);
 324     }
 325   }
 326 }
 327
 328
 329 OldSpace* Heap::TargetSpace(HeapObject* object) {
 330   InstanceType type = object->map()->instance_type();
 331   AllocationSpace space = TargetSpaceId(type);
 332   return (space == OLD_POINTER_SPACE)
 333       ? old_pointer_space_
 334       : old_data_space_;
 335 }
 336
 337
 338 AllocationSpace Heap::TargetSpaceId(InstanceType type) {
 339   // Heap numbers and sequential strings are promoted to old data space, all
 340   // other object types are promoted to old pointer space.  We do not use
 341   // object->IsHeapNumber() and object->IsSeqString() because we already
 342   // know that object has the heap object tag.
 343
 344   // These objects are never allocated in new space.
 345   ASSERT(type != MAP_TYPE);
 346   ASSERT(type != CODE_TYPE);
 347   ASSERT(type != ODDBALL_TYPE);
 348   ASSERT(type != JS_GLOBAL_PROPERTY_CELL_TYPE);
 349
 350   if (type < FIRST_NONSTRING_TYPE) {
 351     // There are four string representations: sequential strings, external
 352     // strings, cons strings, and sliced strings.
 353     // Only the latter two contain non-map-word pointers to heap objects.
 354     return ((type & kIsIndirectStringMask) == kIsIndirectStringTag)
 355         ? OLD_POINTER_SPACE
 356         : OLD_DATA_SPACE;
 357   } else {
 358     return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
 359   }
 360 }
 361
 362
 363 void Heap::CopyBlock(Address dst, Address src, int byte_size) {
 364   CopyWords(reinterpret_cast<Object**>(dst),
 365             reinterpret_cast<Object**>(src),
 366             byte_size / kPointerSize);
 367 }
 368
 369
 370 void Heap::MoveBlock(Address dst, Address src, int byte_size) {
 371   ASSERT(IsAligned(byte_size, kPointerSize));
 372
 373   int size_in_words = byte_size / kPointerSize;
 374
 375   if ((dst < src) || (dst >= (src + byte_size))) {
 376     Object** src_slot = reinterpret_cast<Object**>(src);
 377     Object** dst_slot = reinterpret_cast<Object**>(dst);
 378     Object** end_slot = src_slot + size_in_words;
 379
 380     while (src_slot != end_slot) {
 381       *dst_slot++ = *src_slot++;
 382     }
 383   } else {
 384     memmove(dst, src, byte_size);
 385   }
 386 }
 387
 388
 389 void Heap::ScavengePointer(HeapObject** p) {
 390   ScavengeObject(p, *p);
 391 }
 392
 393
 394 void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
 395   ASSERT(HEAP->InFromSpace(object));
 396
 397   // We use the first word (where the map pointer usually is) of a heap
 398   // object to record the forwarding pointer.  A forwarding pointer can
 399   // point to an old space, the code space, or the to space of the new
 400   // generation.
 401   MapWord first_word = object->map_word();
 402
 403   // If the first word is a forwarding address, the object has already been
 404   // copied.
 405   if (first_word.IsForwardingAddress()) {
 406     HeapObject* dest = first_word.ToForwardingAddress();
 407     ASSERT(HEAP->InFromSpace(*p));
 408     *p = dest;
 409     return;
 410   }
 411
 412   // Call the slow part of scavenge object.
 413   return ScavengeObjectSlow(p, object);
 414 }
 415
 416
 417 bool Heap::CollectGarbage(AllocationSpace space) {
 418   return CollectGarbage(space, SelectGarbageCollector(space));
 419 }
 420
 421
 422 MaybeObject* Heap::PrepareForCompare(String* str) {
 423   // Always flatten small strings and force flattening of long strings
 424   // after we have accumulated a certain amount we failed to flatten.
 425   static const int kMaxAlwaysFlattenLength = 32;
 426   static const int kFlattenLongThreshold = 16*KB;
 427
 428   const int length = str->length();
 429   MaybeObject* obj = str->TryFlatten();
 430   if (length <= kMaxAlwaysFlattenLength ||
 431       unflattened_strings_length_ >= kFlattenLongThreshold) {
 432     return obj;
 433   }
 434   if (obj->IsFailure()) {
 435     unflattened_strings_length_ += length;
 436   }
 437   return str;
 438 }
 439
 440
 441 int Heap::AdjustAmountOfExternalAllocatedMemory(int change_in_bytes) {
 442   ASSERT(HasBeenSetup());
 443   int amount = amount_of_external_allocated_memory_ + change_in_bytes;
 444   if (change_in_bytes >= 0) {
 445     // Avoid overflow.
 446     if (amount > amount_of_external_allocated_memory_) {
 447       amount_of_external_allocated_memory_ = amount;
 448     }
 449     int amount_since_last_global_gc =
 450         amount_of_external_allocated_memory_ -
 451         amount_of_external_allocated_memory_at_last_global_gc_;
 452     if (amount_since_last_global_gc > external_allocation_limit_) {
 453       CollectAllGarbage(kNoGCFlags);
 454     }
 455   } else {
 456     // Avoid underflow.
 457     if (amount >= 0) {
 458       amount_of_external_allocated_memory_ = amount;
 459     }
 460   }
 461   ASSERT(amount_of_external_allocated_memory_ >= 0);
 462   return amount_of_external_allocated_memory_;
 463 }
 464
 465
 466 void Heap::SetLastScriptId(Object* last_script_id) {
 467   roots_[kLastScriptIdRootIndex] = last_script_id;
 468 }
 469
 470
 471 Isolate* Heap::isolate() {
 472   return reinterpret_cast<Isolate*>(reinterpret_cast<intptr_t>(this) -
 473       reinterpret_cast<size_t>(reinterpret_cast<Isolate*>(4)->heap()) + 4);
 474 }
 475
 476
 477 #ifdef DEBUG
 478 #define GC_GREEDY_CHECK() \
 479   if (FLAG_gc_greedy) HEAP->GarbageCollectionGreedyCheck()
 480 #else
 481 #define GC_GREEDY_CHECK() { }
 482 #endif
 483
 484
 485 // Calls the FUNCTION_CALL function and retries it up to three times
 486 // to guarantee that any allocations performed during the call will
 487 // succeed if there's enough memory.
 488
 489 // Warning: Do not use the identifiers __object__, __maybe_object__ or
 490 // __scope__ in a call to this macro.
 491
 492 #define CALL_AND_RETRY(ISOLATE, FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY)\
 493   do {                                                                    \
 494     GC_GREEDY_CHECK();                                                    \
 495     MaybeObject* __maybe_object__ = FUNCTION_CALL;                        \
 496     Object* __object__ = NULL;                                            \
 497     if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE;            \
 498     if (__maybe_object__->IsOutOfMemory()) {                              \
 499       v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_0", true);\
 500     }                                                                     \
 501     if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY;                \
 502     ISOLATE->heap()->CollectGarbage(Failure::cast(__maybe_object__)->     \
 503                                     allocation_space());                  \
 504     __maybe_object__ = FUNCTION_CALL;                                     \
 505     if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE;            \
 506     if (__maybe_object__->IsOutOfMemory()) {                              \
 507       v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_1", true);\
 508     }                                                                     \
 509     if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY;                \
 510     ISOLATE->counters()->gc_last_resort_from_handles()->Increment();      \
 511     ISOLATE->heap()->CollectAllAvailableGarbage();                        \
 512     {                                                                     \
 513       AlwaysAllocateScope __scope__;                                      \
 514       __maybe_object__ = FUNCTION_CALL;                                   \
 515     }                                                                     \
 516     if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE;            \
 517     if (__maybe_object__->IsOutOfMemory() ||                              \
 518         __maybe_object__->IsRetryAfterGC()) {                             \
 519       /* TODO(1181417): Fix this. */                                      \
 520       v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_2", true);\
 521     }                                                                     \
 522     RETURN_EMPTY;                                                         \
 523   } while (false)
 524
 525
 526 #define CALL_HEAP_FUNCTION(ISOLATE, FUNCTION_CALL, TYPE)       \
 527   CALL_AND_RETRY(ISOLATE,                                      \
 528                  FUNCTION_CALL,                                \
 529                  return Handle<TYPE>(TYPE::cast(__object__), ISOLATE),  \
 530                  return Handle<TYPE>())
 531
 532
 533 #define CALL_HEAP_FUNCTION_VOID(ISOLATE, FUNCTION_CALL) \
 534   CALL_AND_RETRY(ISOLATE, FUNCTION_CALL, return, return)
 535
 536
 537 #ifdef DEBUG
 538
 539 inline bool Heap::allow_allocation(bool new_state) {
 540   bool old = allocation_allowed_;
 541   allocation_allowed_ = new_state;
 542   return old;
 543 }
 544
 545 #endif
 546
 547
 548 void ExternalStringTable::AddString(String* string) {
 549   ASSERT(string->IsExternalString());
 550   if (heap_->InNewSpace(string)) {
 551     new_space_strings_.Add(string);
 552   } else {
 553     old_space_strings_.Add(string);
 554   }
 555 }
 556
 557
 558 void ExternalStringTable::Iterate(ObjectVisitor* v) {
 559   if (!new_space_strings_.is_empty()) {
 560     Object** start = &new_space_strings_[0];
 561     v->VisitPointers(start, start + new_space_strings_.length());
 562   }
 563   if (!old_space_strings_.is_empty()) {
 564     Object** start = &old_space_strings_[0];
 565     v->VisitPointers(start, start + old_space_strings_.length());
 566   }
 567 }
 568
 569
 570 // Verify() is inline to avoid ifdef-s around its calls in release
 571 // mode.
 572 void ExternalStringTable::Verify() {
 573 #ifdef DEBUG
 574   for (int i = 0; i < new_space_strings_.length(); ++i) {
 575     ASSERT(heap_->InNewSpace(new_space_strings_[i]));
 576     ASSERT(new_space_strings_[i] != HEAP->raw_unchecked_null_value());
 577   }
 578   for (int i = 0; i < old_space_strings_.length(); ++i) {
 579     ASSERT(!heap_->InNewSpace(old_space_strings_[i]));
 580     ASSERT(old_space_strings_[i] != HEAP->raw_unchecked_null_value());
 581   }
 582 #endif
 583 }
 584
 585
 586 void ExternalStringTable::AddOldString(String* string) {
 587   ASSERT(string->IsExternalString());
 588   ASSERT(!heap_->InNewSpace(string));
 589   old_space_strings_.Add(string);
 590 }
 591
 592
 593 void ExternalStringTable::ShrinkNewStrings(int position) {
 594   new_space_strings_.Rewind(position);
 595   if (FLAG_verify_heap) {
 596     Verify();
 597   }
 598 }
 599
 600
 601 void Heap::ClearInstanceofCache() {
 602   set_instanceof_cache_function(the_hole_value());
 603 }
 604
 605
 606 Object* Heap::ToBoolean(bool condition) {
 607   return condition ? true_value() : false_value();
 608 }
 609
 610
 611 void Heap::CompletelyClearInstanceofCache() {
 612   set_instanceof_cache_map(the_hole_value());
 613   set_instanceof_cache_function(the_hole_value());
 614 }
 615
 616
 617 MaybeObject* TranscendentalCache::Get(Type type, double input) {
 618   SubCache* cache = caches_[type];
 619   if (cache == NULL) {
 620     caches_[type] = cache = new SubCache(type);
 621   }
 622   return cache->Get(input);
 623 }
 624
 625
 626 Address TranscendentalCache::cache_array_address() {
 627   return reinterpret_cast<Address>(caches_);
 628 }
 629
 630
 631 double TranscendentalCache::SubCache::Calculate(double input) {
 632   switch (type_) {
 633     case ACOS:
 634       return acos(input);
 635     case ASIN:
 636       return asin(input);
 637     case ATAN:
 638       return atan(input);
 639     case COS:
 640       return cos(input);
 641     case EXP:
 642       return exp(input);
 643     case LOG:
 644       return log(input);
 645     case SIN:
 646       return sin(input);
 647     case TAN:
 648       return tan(input);
 649     default:
 650       return 0.0;  // Never happens.
 651   }
 652 }
 653
 654
 655 MaybeObject* TranscendentalCache::SubCache::Get(double input) {
 656   Converter c;
 657   c.dbl = input;
 658   int hash = Hash(c);
 659   Element e = elements_[hash];
 660   if (e.in[0] == c.integers[0] &&
 661       e.in[1] == c.integers[1]) {
 662     ASSERT(e.output != NULL);
 663     isolate_->counters()->transcendental_cache_hit()->Increment();
 664     return e.output;
 665   }
 666   double answer = Calculate(input);
 667   isolate_->counters()->transcendental_cache_miss()->Increment();
 668   Object* heap_number;
 669   { MaybeObject* maybe_heap_number =
 670         isolate_->heap()->AllocateHeapNumber(answer);
 671     if (!maybe_heap_number->ToObject(&heap_number)) return maybe_heap_number;
 672   }
 673   elements_[hash].in[0] = c.integers[0];
 674   elements_[hash].in[1] = c.integers[1];
 675   elements_[hash].output = heap_number;
 676   return heap_number;
 677 }
 678
 679
 680 Heap* _inline_get_heap_() {
 681   return HEAP;
 682 }
 683
 684
 685 } }  // namespace v8::internal
 686
 687 #endif  // V8_HEAP_INL_H_