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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     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 "platform.h"
     36 #include "v8-counters.h"
     37 #include "store-buffer.h"
     38 #include "store-buffer-inl.h"
     39 
     40 namespace v8 {
     41 namespace internal {
     42 
     43 void PromotionQueue::insert(HeapObject* target, int size) {
     44   if (emergency_stack_ != NULL) {
     45     emergency_stack_->Add(Entry(target, size));
     46     return;
     47   }
     48 
     49   if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(rear_))) {
     50     NewSpacePage* rear_page =
     51         NewSpacePage::FromAddress(reinterpret_cast<Address>(rear_));
     52     ASSERT(!rear_page->prev_page()->is_anchor());
     53     rear_ = reinterpret_cast<intptr_t*>(rear_page->prev_page()->area_end());
     54     ActivateGuardIfOnTheSamePage();
     55   }
     56 
     57   if (guard_) {
     58     ASSERT(GetHeadPage() ==
     59            Page::FromAllocationTop(reinterpret_cast<Address>(limit_)));
     60 
     61     if ((rear_ - 2) < limit_) {
     62       RelocateQueueHead();
     63       emergency_stack_->Add(Entry(target, size));
     64       return;
     65     }
     66   }
     67 
     68   *(--rear_) = reinterpret_cast<intptr_t>(target);
     69   *(--rear_) = size;
     70   // Assert no overflow into live objects.
     71 #ifdef DEBUG
     72   SemiSpace::AssertValidRange(target->GetIsolate()->heap()->new_space()->top(),
     73                               reinterpret_cast<Address>(rear_));
     74 #endif
     75 }
     76 
     77 
     78 void PromotionQueue::ActivateGuardIfOnTheSamePage() {
     79   guard_ = guard_ ||
     80       heap_->new_space()->active_space()->current_page()->address() ==
     81       GetHeadPage()->address();
     82 }
     83 
     84 
     85 MaybeObject* Heap::AllocateStringFromUtf8(Vector<const char> str,
     86                                           PretenureFlag pretenure) {
     87   // Check for ASCII first since this is the common case.
     88   const char* start = str.start();
     89   int length = str.length();
     90   int non_ascii_start = String::NonAsciiStart(start, length);
     91   if (non_ascii_start >= length) {
     92     // If the string is ASCII, we do not need to convert the characters
     93     // since UTF8 is backwards compatible with ASCII.
     94     return AllocateStringFromOneByte(str, pretenure);
     95   }
     96   // Non-ASCII and we need to decode.
     97   return AllocateStringFromUtf8Slow(str, non_ascii_start, pretenure);
     98 }
     99 
    100 
    101 template<>
    102 bool inline Heap::IsOneByte(Vector<const char> str, int chars) {
    103   // TODO(dcarney): incorporate Latin-1 check when Latin-1 is supported?
    104   // ASCII only check.
    105   return chars == str.length();
    106 }
    107 
    108 
    109 template<>
    110 bool inline Heap::IsOneByte(String* str, int chars) {
    111   return str->IsOneByteRepresentation();
    112 }
    113 
    114 
    115 MaybeObject* Heap::AllocateInternalizedStringFromUtf8(
    116     Vector<const char> str, int chars, uint32_t hash_field) {
    117   if (IsOneByte(str, chars)) {
    118     return AllocateOneByteInternalizedString(
    119         Vector<const uint8_t>::cast(str), hash_field);
    120   }
    121   return AllocateInternalizedStringImpl<false>(str, chars, hash_field);
    122 }
    123 
    124 
    125 template<typename T>
    126 MaybeObject* Heap::AllocateInternalizedStringImpl(
    127     T t, int chars, uint32_t hash_field) {
    128   if (IsOneByte(t, chars)) {
    129     return AllocateInternalizedStringImpl<true>(t, chars, hash_field);
    130   }
    131   return AllocateInternalizedStringImpl<false>(t, chars, hash_field);
    132 }
    133 
    134 
    135 MaybeObject* Heap::AllocateOneByteInternalizedString(Vector<const uint8_t> str,
    136                                                      uint32_t hash_field) {
    137   if (str.length() > SeqOneByteString::kMaxLength) {
    138     return Failure::OutOfMemoryException(0x2);
    139   }
    140   // Compute map and object size.
    141   Map* map = ascii_internalized_string_map();
    142   int size = SeqOneByteString::SizeFor(str.length());
    143   AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
    144 
    145   // Allocate string.
    146   Object* result;
    147   { MaybeObject* maybe_result = AllocateRaw(size, space, OLD_DATA_SPACE);
    148     if (!maybe_result->ToObject(&result)) return maybe_result;
    149   }
    150 
    151   // String maps are all immortal immovable objects.
    152   reinterpret_cast<HeapObject*>(result)->set_map_no_write_barrier(map);
    153   // Set length and hash fields of the allocated string.
    154   String* answer = String::cast(result);
    155   answer->set_length(str.length());
    156   answer->set_hash_field(hash_field);
    157 
    158   ASSERT_EQ(size, answer->Size());
    159 
    160   // Fill in the characters.
    161   OS::MemCopy(answer->address() + SeqOneByteString::kHeaderSize,
    162               str.start(), str.length());
    163 
    164   return answer;
    165 }
    166 
    167 
    168 MaybeObject* Heap::AllocateTwoByteInternalizedString(Vector<const uc16> str,
    169                                                      uint32_t hash_field) {
    170   if (str.length() > SeqTwoByteString::kMaxLength) {
    171     return Failure::OutOfMemoryException(0x3);
    172   }
    173   // Compute map and object size.
    174   Map* map = internalized_string_map();
    175   int size = SeqTwoByteString::SizeFor(str.length());
    176   AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
    177 
    178   // Allocate string.
    179   Object* result;
    180   { MaybeObject* maybe_result = AllocateRaw(size, space, OLD_DATA_SPACE);
    181     if (!maybe_result->ToObject(&result)) return maybe_result;
    182   }
    183 
    184   reinterpret_cast<HeapObject*>(result)->set_map(map);
    185   // Set length and hash fields of the allocated string.
    186   String* answer = String::cast(result);
    187   answer->set_length(str.length());
    188   answer->set_hash_field(hash_field);
    189 
    190   ASSERT_EQ(size, answer->Size());
    191 
    192   // Fill in the characters.
    193   OS::MemCopy(answer->address() + SeqTwoByteString::kHeaderSize,
    194               str.start(), str.length() * kUC16Size);
    195 
    196   return answer;
    197 }
    198 
    199 MaybeObject* Heap::CopyFixedArray(FixedArray* src) {
    200   return CopyFixedArrayWithMap(src, src->map());
    201 }
    202 
    203 
    204 MaybeObject* Heap::CopyFixedDoubleArray(FixedDoubleArray* src) {
    205   return CopyFixedDoubleArrayWithMap(src, src->map());
    206 }
    207 
    208 
    209 MaybeObject* Heap::CopyConstantPoolArray(ConstantPoolArray* src) {
    210   return CopyConstantPoolArrayWithMap(src, src->map());
    211 }
    212 
    213 
    214 MaybeObject* Heap::AllocateRaw(int size_in_bytes,
    215                                AllocationSpace space,
    216                                AllocationSpace retry_space) {
    217   ASSERT(AllowHandleAllocation::IsAllowed());
    218   ASSERT(AllowHeapAllocation::IsAllowed());
    219   ASSERT(gc_state_ == NOT_IN_GC);
    220   HeapProfiler* profiler = isolate_->heap_profiler();
    221 #ifdef DEBUG
    222   if (FLAG_gc_interval >= 0 &&
    223       !disallow_allocation_failure_ &&
    224       Heap::allocation_timeout_-- <= 0) {
    225     return Failure::RetryAfterGC(space);
    226   }
    227   isolate_->counters()->objs_since_last_full()->Increment();
    228   isolate_->counters()->objs_since_last_young()->Increment();
    229 #endif
    230 
    231   HeapObject* object;
    232   MaybeObject* result;
    233   if (NEW_SPACE == space) {
    234     result = new_space_.AllocateRaw(size_in_bytes);
    235     if (always_allocate() && result->IsFailure() && retry_space != NEW_SPACE) {
    236       space = retry_space;
    237     } else {
    238       if (profiler->is_tracking_allocations() && result->To(&object)) {
    239         profiler->AllocationEvent(object->address(), size_in_bytes);
    240       }
    241       return result;
    242     }
    243   }
    244 
    245   if (OLD_POINTER_SPACE == space) {
    246     result = old_pointer_space_->AllocateRaw(size_in_bytes);
    247   } else if (OLD_DATA_SPACE == space) {
    248     result = old_data_space_->AllocateRaw(size_in_bytes);
    249   } else if (CODE_SPACE == space) {
    250     result = code_space_->AllocateRaw(size_in_bytes);
    251   } else if (LO_SPACE == space) {
    252     result = lo_space_->AllocateRaw(size_in_bytes, NOT_EXECUTABLE);
    253   } else if (CELL_SPACE == space) {
    254     result = cell_space_->AllocateRaw(size_in_bytes);
    255   } else if (PROPERTY_CELL_SPACE == space) {
    256     result = property_cell_space_->AllocateRaw(size_in_bytes);
    257   } else {
    258     ASSERT(MAP_SPACE == space);
    259     result = map_space_->AllocateRaw(size_in_bytes);
    260   }
    261   if (result->IsFailure()) old_gen_exhausted_ = true;
    262   if (profiler->is_tracking_allocations() && result->To(&object)) {
    263     profiler->AllocationEvent(object->address(), size_in_bytes);
    264   }
    265   return result;
    266 }
    267 
    268 
    269 MaybeObject* Heap::NumberFromInt32(
    270     int32_t value, PretenureFlag pretenure) {
    271   if (Smi::IsValid(value)) return Smi::FromInt(value);
    272   // Bypass NumberFromDouble to avoid various redundant checks.
    273   return AllocateHeapNumber(FastI2D(value), pretenure);
    274 }
    275 
    276 
    277 MaybeObject* Heap::NumberFromUint32(
    278     uint32_t value, PretenureFlag pretenure) {
    279   if (static_cast<int32_t>(value) >= 0 &&
    280       Smi::IsValid(static_cast<int32_t>(value))) {
    281     return Smi::FromInt(static_cast<int32_t>(value));
    282   }
    283   // Bypass NumberFromDouble to avoid various redundant checks.
    284   return AllocateHeapNumber(FastUI2D(value), pretenure);
    285 }
    286 
    287 
    288 void Heap::FinalizeExternalString(String* string) {
    289   ASSERT(string->IsExternalString());
    290   v8::String::ExternalStringResourceBase** resource_addr =
    291       reinterpret_cast<v8::String::ExternalStringResourceBase**>(
    292           reinterpret_cast<byte*>(string) +
    293           ExternalString::kResourceOffset -
    294           kHeapObjectTag);
    295 
    296   // Dispose of the C++ object if it has not already been disposed.
    297   if (*resource_addr != NULL) {
    298     (*resource_addr)->Dispose();
    299     *resource_addr = NULL;
    300   }
    301 }
    302 
    303 
    304 bool Heap::InNewSpace(Object* object) {
    305   bool result = new_space_.Contains(object);
    306   ASSERT(!result ||                  // Either not in new space
    307          gc_state_ != NOT_IN_GC ||   // ... or in the middle of GC
    308          InToSpace(object));         // ... or in to-space (where we allocate).
    309   return result;
    310 }
    311 
    312 
    313 bool Heap::InNewSpace(Address address) {
    314   return new_space_.Contains(address);
    315 }
    316 
    317 
    318 bool Heap::InFromSpace(Object* object) {
    319   return new_space_.FromSpaceContains(object);
    320 }
    321 
    322 
    323 bool Heap::InToSpace(Object* object) {
    324   return new_space_.ToSpaceContains(object);
    325 }
    326 
    327 
    328 bool Heap::InOldPointerSpace(Address address) {
    329   return old_pointer_space_->Contains(address);
    330 }
    331 
    332 
    333 bool Heap::InOldPointerSpace(Object* object) {
    334   return InOldPointerSpace(reinterpret_cast<Address>(object));
    335 }
    336 
    337 
    338 bool Heap::InOldDataSpace(Address address) {
    339   return old_data_space_->Contains(address);
    340 }
    341 
    342 
    343 bool Heap::InOldDataSpace(Object* object) {
    344   return InOldDataSpace(reinterpret_cast<Address>(object));
    345 }
    346 
    347 
    348 bool Heap::OldGenerationAllocationLimitReached() {
    349   if (!incremental_marking()->IsStopped()) return false;
    350   return OldGenerationSpaceAvailable() < 0;
    351 }
    352 
    353 
    354 bool Heap::ShouldBePromoted(Address old_address, int object_size) {
    355   // An object should be promoted if:
    356   // - the object has survived a scavenge operation or
    357   // - to space is already 25% full.
    358   NewSpacePage* page = NewSpacePage::FromAddress(old_address);
    359   Address age_mark = new_space_.age_mark();
    360   bool below_mark = page->IsFlagSet(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK) &&
    361       (!page->ContainsLimit(age_mark) || old_address < age_mark);
    362   return below_mark || (new_space_.Size() + object_size) >=
    363                         (new_space_.EffectiveCapacity() >> 2);
    364 }
    365 
    366 
    367 void Heap::RecordWrite(Address address, int offset) {
    368   if (!InNewSpace(address)) store_buffer_.Mark(address + offset);
    369 }
    370 
    371 
    372 void Heap::RecordWrites(Address address, int start, int len) {
    373   if (!InNewSpace(address)) {
    374     for (int i = 0; i < len; i++) {
    375       store_buffer_.Mark(address + start + i * kPointerSize);
    376     }
    377   }
    378 }
    379 
    380 
    381 OldSpace* Heap::TargetSpace(HeapObject* object) {
    382   InstanceType type = object->map()->instance_type();
    383   AllocationSpace space = TargetSpaceId(type);
    384   return (space == OLD_POINTER_SPACE)
    385       ? old_pointer_space_
    386       : old_data_space_;
    387 }
    388 
    389 
    390 AllocationSpace Heap::TargetSpaceId(InstanceType type) {
    391   // Heap numbers and sequential strings are promoted to old data space, all
    392   // other object types are promoted to old pointer space.  We do not use
    393   // object->IsHeapNumber() and object->IsSeqString() because we already
    394   // know that object has the heap object tag.
    395 
    396   // These objects are never allocated in new space.
    397   ASSERT(type != MAP_TYPE);
    398   ASSERT(type != CODE_TYPE);
    399   ASSERT(type != ODDBALL_TYPE);
    400   ASSERT(type != CELL_TYPE);
    401   ASSERT(type != PROPERTY_CELL_TYPE);
    402 
    403   if (type <= LAST_NAME_TYPE) {
    404     if (type == SYMBOL_TYPE) return OLD_POINTER_SPACE;
    405     ASSERT(type < FIRST_NONSTRING_TYPE);
    406     // There are four string representations: sequential strings, external
    407     // strings, cons strings, and sliced strings.
    408     // Only the latter two contain non-map-word pointers to heap objects.
    409     return ((type & kIsIndirectStringMask) == kIsIndirectStringTag)
    410         ? OLD_POINTER_SPACE
    411         : OLD_DATA_SPACE;
    412   } else {
    413     return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
    414   }
    415 }
    416 
    417 
    418 bool Heap::AllowedToBeMigrated(HeapObject* object, AllocationSpace dst) {
    419   // Object migration is governed by the following rules:
    420   //
    421   // 1) Objects in new-space can be migrated to one of the old spaces
    422   //    that matches their target space or they stay in new-space.
    423   // 2) Objects in old-space stay in the same space when migrating.
    424   // 3) Fillers (two or more words) can migrate due to left-trimming of
    425   //    fixed arrays in new-space, old-data-space and old-pointer-space.
    426   // 4) Fillers (one word) can never migrate, they are skipped by
    427   //    incremental marking explicitly to prevent invalid pattern.
    428   //
    429   // Since this function is used for debugging only, we do not place
    430   // asserts here, but check everything explicitly.
    431   if (object->map() == one_pointer_filler_map()) return false;
    432   InstanceType type = object->map()->instance_type();
    433   MemoryChunk* chunk = MemoryChunk::FromAddress(object->address());
    434   AllocationSpace src = chunk->owner()->identity();
    435   switch (src) {
    436     case NEW_SPACE:
    437       return dst == src || dst == TargetSpaceId(type);
    438     case OLD_POINTER_SPACE:
    439       return dst == src && (dst == TargetSpaceId(type) || object->IsFiller());
    440     case OLD_DATA_SPACE:
    441       return dst == src && dst == TargetSpaceId(type);
    442     case CODE_SPACE:
    443       return dst == src && type == CODE_TYPE;
    444     case MAP_SPACE:
    445     case CELL_SPACE:
    446     case PROPERTY_CELL_SPACE:
    447     case LO_SPACE:
    448       return false;
    449   }
    450   UNREACHABLE();
    451   return false;
    452 }
    453 
    454 
    455 void Heap::CopyBlock(Address dst, Address src, int byte_size) {
    456   CopyWords(reinterpret_cast<Object**>(dst),
    457             reinterpret_cast<Object**>(src),
    458             static_cast<size_t>(byte_size / kPointerSize));
    459 }
    460 
    461 
    462 void Heap::MoveBlock(Address dst, Address src, int byte_size) {
    463   ASSERT(IsAligned(byte_size, kPointerSize));
    464 
    465   int size_in_words = byte_size / kPointerSize;
    466 
    467   if ((dst < src) || (dst >= (src + byte_size))) {
    468     Object** src_slot = reinterpret_cast<Object**>(src);
    469     Object** dst_slot = reinterpret_cast<Object**>(dst);
    470     Object** end_slot = src_slot + size_in_words;
    471 
    472     while (src_slot != end_slot) {
    473       *dst_slot++ = *src_slot++;
    474     }
    475   } else {
    476     OS::MemMove(dst, src, static_cast<size_t>(byte_size));
    477   }
    478 }
    479 
    480 
    481 void Heap::ScavengePointer(HeapObject** p) {
    482   ScavengeObject(p, *p);
    483 }
    484 
    485 
    486 void Heap::UpdateAllocationSiteFeedback(HeapObject* object) {
    487   if (FLAG_allocation_site_pretenuring && object->IsJSObject()) {
    488     AllocationMemento* memento = AllocationMemento::FindForJSObject(
    489         JSObject::cast(object), true);
    490     if (memento != NULL) {
    491       ASSERT(memento->IsValid());
    492       memento->GetAllocationSite()->IncrementMementoFoundCount();
    493     }
    494   }
    495 }
    496 
    497 
    498 void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
    499   ASSERT(object->GetIsolate()->heap()->InFromSpace(object));
    500 
    501   // We use the first word (where the map pointer usually is) of a heap
    502   // object to record the forwarding pointer.  A forwarding pointer can
    503   // point to an old space, the code space, or the to space of the new
    504   // generation.
    505   MapWord first_word = object->map_word();
    506 
    507   // If the first word is a forwarding address, the object has already been
    508   // copied.
    509   if (first_word.IsForwardingAddress()) {
    510     HeapObject* dest = first_word.ToForwardingAddress();
    511     ASSERT(object->GetIsolate()->heap()->InFromSpace(*p));
    512     *p = dest;
    513     return;
    514   }
    515 
    516   UpdateAllocationSiteFeedback(object);
    517 
    518   // AllocationMementos are unrooted and shouldn't survive a scavenge
    519   ASSERT(object->map() != object->GetHeap()->allocation_memento_map());
    520   // Call the slow part of scavenge object.
    521   return ScavengeObjectSlow(p, object);
    522 }
    523 
    524 
    525 bool Heap::CollectGarbage(AllocationSpace space, const char* gc_reason) {
    526   const char* collector_reason = NULL;
    527   GarbageCollector collector = SelectGarbageCollector(space, &collector_reason);
    528   return CollectGarbage(space, collector, gc_reason, collector_reason);
    529 }
    530 
    531 
    532 MaybeObject* Heap::PrepareForCompare(String* str) {
    533   // Always flatten small strings and force flattening of long strings
    534   // after we have accumulated a certain amount we failed to flatten.
    535   static const int kMaxAlwaysFlattenLength = 32;
    536   static const int kFlattenLongThreshold = 16*KB;
    537 
    538   const int length = str->length();
    539   MaybeObject* obj = str->TryFlatten();
    540   if (length <= kMaxAlwaysFlattenLength ||
    541       unflattened_strings_length_ >= kFlattenLongThreshold) {
    542     return obj;
    543   }
    544   if (obj->IsFailure()) {
    545     unflattened_strings_length_ += length;
    546   }
    547   return str;
    548 }
    549 
    550 
    551 int64_t Heap::AdjustAmountOfExternalAllocatedMemory(
    552     int64_t change_in_bytes) {
    553   ASSERT(HasBeenSetUp());
    554   int64_t amount = amount_of_external_allocated_memory_ + change_in_bytes;
    555   if (change_in_bytes > 0) {
    556     // Avoid overflow.
    557     if (amount > amount_of_external_allocated_memory_) {
    558       amount_of_external_allocated_memory_ = amount;
    559     } else {
    560       // Give up and reset the counters in case of an overflow.
    561       amount_of_external_allocated_memory_ = 0;
    562       amount_of_external_allocated_memory_at_last_global_gc_ = 0;
    563     }
    564     int64_t amount_since_last_global_gc = PromotedExternalMemorySize();
    565     if (amount_since_last_global_gc > external_allocation_limit_) {
    566       CollectAllGarbage(kNoGCFlags, "external memory allocation limit reached");
    567     }
    568   } else {
    569     // Avoid underflow.
    570     if (amount >= 0) {
    571       amount_of_external_allocated_memory_ = amount;
    572     } else {
    573       // Give up and reset the counters in case of an underflow.
    574       amount_of_external_allocated_memory_ = 0;
    575       amount_of_external_allocated_memory_at_last_global_gc_ = 0;
    576     }
    577   }
    578   if (FLAG_trace_external_memory) {
    579     PrintPID("%8.0f ms: ", isolate()->time_millis_since_init());
    580     PrintF("Adjust amount of external memory: delta=%6" V8_PTR_PREFIX "d KB, "
    581            "amount=%6" V8_PTR_PREFIX "d KB, since_gc=%6" V8_PTR_PREFIX "d KB, "
    582            "isolate=0x%08" V8PRIxPTR ".\n",
    583            static_cast<intptr_t>(change_in_bytes / KB),
    584            static_cast<intptr_t>(amount_of_external_allocated_memory_ / KB),
    585            static_cast<intptr_t>(PromotedExternalMemorySize() / KB),
    586            reinterpret_cast<intptr_t>(isolate()));
    587   }
    588   ASSERT(amount_of_external_allocated_memory_ >= 0);
    589   return amount_of_external_allocated_memory_;
    590 }
    591 
    592 
    593 Isolate* Heap::isolate() {
    594   return reinterpret_cast<Isolate*>(reinterpret_cast<intptr_t>(this) -
    595       reinterpret_cast<size_t>(reinterpret_cast<Isolate*>(4)->heap()) + 4);
    596 }
    597 
    598 
    599 #ifdef DEBUG
    600 #define GC_GREEDY_CHECK(ISOLATE) \
    601   if (FLAG_gc_greedy) (ISOLATE)->heap()->GarbageCollectionGreedyCheck()
    602 #else
    603 #define GC_GREEDY_CHECK(ISOLATE) { }
    604 #endif
    605 
    606 // Calls the FUNCTION_CALL function and retries it up to three times
    607 // to guarantee that any allocations performed during the call will
    608 // succeed if there's enough memory.
    609 
    610 // Warning: Do not use the identifiers __object__, __maybe_object__ or
    611 // __scope__ in a call to this macro.
    612 
    613 #define CALL_AND_RETRY(ISOLATE, FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY, OOM)\
    614   do {                                                                         \
    615     GC_GREEDY_CHECK(ISOLATE);                                                  \
    616     MaybeObject* __maybe_object__ = FUNCTION_CALL;                             \
    617     Object* __object__ = NULL;                                                 \
    618     if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE;                 \
    619     if (__maybe_object__->IsOutOfMemory()) {                                   \
    620       OOM;                                                                     \
    621     }                                                                          \
    622     if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY;                     \
    623     (ISOLATE)->heap()->CollectGarbage(Failure::cast(__maybe_object__)->        \
    624                                     allocation_space(),                        \
    625                                     "allocation failure");                     \
    626     __maybe_object__ = FUNCTION_CALL;                                          \
    627     if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE;                 \
    628     if (__maybe_object__->IsOutOfMemory()) {                                   \
    629       OOM;                                                                     \
    630     }                                                                          \
    631     if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY;                     \
    632     (ISOLATE)->counters()->gc_last_resort_from_handles()->Increment();         \
    633     (ISOLATE)->heap()->CollectAllAvailableGarbage("last resort gc");           \
    634     {                                                                          \
    635       AlwaysAllocateScope __scope__;                                           \
    636       __maybe_object__ = FUNCTION_CALL;                                        \
    637     }                                                                          \
    638     if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE;                 \
    639     if (__maybe_object__->IsOutOfMemory()) {                                   \
    640       OOM;                                                                     \
    641     }                                                                          \
    642     if (__maybe_object__->IsRetryAfterGC()) {                                  \
    643       /* TODO(1181417): Fix this. */                                           \
    644       v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_LAST", true);  \
    645     }                                                                          \
    646     RETURN_EMPTY;                                                              \
    647   } while (false)
    648 
    649 #define CALL_AND_RETRY_OR_DIE(                                             \
    650      ISOLATE, FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY)                   \
    651   CALL_AND_RETRY(                                                          \
    652       ISOLATE,                                                             \
    653       FUNCTION_CALL,                                                       \
    654       RETURN_VALUE,                                                        \
    655       RETURN_EMPTY,                                                        \
    656       v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY", true))
    657 
    658 #define CALL_HEAP_FUNCTION(ISOLATE, FUNCTION_CALL, TYPE)                      \
    659   CALL_AND_RETRY_OR_DIE(ISOLATE,                                              \
    660                         FUNCTION_CALL,                                        \
    661                         return Handle<TYPE>(TYPE::cast(__object__), ISOLATE), \
    662                         return Handle<TYPE>())                                \
    663 
    664 
    665 #define CALL_HEAP_FUNCTION_VOID(ISOLATE, FUNCTION_CALL)  \
    666   CALL_AND_RETRY_OR_DIE(ISOLATE, FUNCTION_CALL, return, return)
    667 
    668 
    669 #define CALL_HEAP_FUNCTION_PASS_EXCEPTION(ISOLATE, FUNCTION_CALL) \
    670   CALL_AND_RETRY(ISOLATE,                                         \
    671                  FUNCTION_CALL,                                   \
    672                  return __object__,                               \
    673                  return __maybe_object__,                         \
    674                  return __maybe_object__)
    675 
    676 
    677 void ExternalStringTable::AddString(String* string) {
    678   ASSERT(string->IsExternalString());
    679   if (heap_->InNewSpace(string)) {
    680     new_space_strings_.Add(string);
    681   } else {
    682     old_space_strings_.Add(string);
    683   }
    684 }
    685 
    686 
    687 void ExternalStringTable::Iterate(ObjectVisitor* v) {
    688   if (!new_space_strings_.is_empty()) {
    689     Object** start = &new_space_strings_[0];
    690     v->VisitPointers(start, start + new_space_strings_.length());
    691   }
    692   if (!old_space_strings_.is_empty()) {
    693     Object** start = &old_space_strings_[0];
    694     v->VisitPointers(start, start + old_space_strings_.length());
    695   }
    696 }
    697 
    698 
    699 // Verify() is inline to avoid ifdef-s around its calls in release
    700 // mode.
    701 void ExternalStringTable::Verify() {
    702 #ifdef DEBUG
    703   for (int i = 0; i < new_space_strings_.length(); ++i) {
    704     Object* obj = Object::cast(new_space_strings_[i]);
    705     ASSERT(heap_->InNewSpace(obj));
    706     ASSERT(obj != heap_->the_hole_value());
    707   }
    708   for (int i = 0; i < old_space_strings_.length(); ++i) {
    709     Object* obj = Object::cast(old_space_strings_[i]);
    710     ASSERT(!heap_->InNewSpace(obj));
    711     ASSERT(obj != heap_->the_hole_value());
    712   }
    713 #endif
    714 }
    715 
    716 
    717 void ExternalStringTable::AddOldString(String* string) {
    718   ASSERT(string->IsExternalString());
    719   ASSERT(!heap_->InNewSpace(string));
    720   old_space_strings_.Add(string);
    721 }
    722 
    723 
    724 void ExternalStringTable::ShrinkNewStrings(int position) {
    725   new_space_strings_.Rewind(position);
    726 #ifdef VERIFY_HEAP
    727   if (FLAG_verify_heap) {
    728     Verify();
    729   }
    730 #endif
    731 }
    732 
    733 
    734 void Heap::ClearInstanceofCache() {
    735   set_instanceof_cache_function(the_hole_value());
    736 }
    737 
    738 
    739 Object* Heap::ToBoolean(bool condition) {
    740   return condition ? true_value() : false_value();
    741 }
    742 
    743 
    744 void Heap::CompletelyClearInstanceofCache() {
    745   set_instanceof_cache_map(the_hole_value());
    746   set_instanceof_cache_function(the_hole_value());
    747 }
    748 
    749 
    750 MaybeObject* TranscendentalCache::Get(Type type, double input) {
    751   SubCache* cache = caches_[type];
    752   if (cache == NULL) {
    753     caches_[type] = cache = new SubCache(isolate_, type);
    754   }
    755   return cache->Get(input);
    756 }
    757 
    758 
    759 Address TranscendentalCache::cache_array_address() {
    760   return reinterpret_cast<Address>(caches_);
    761 }
    762 
    763 
    764 double TranscendentalCache::SubCache::Calculate(double input) {
    765   switch (type_) {
    766     case ACOS:
    767       return acos(input);
    768     case ASIN:
    769       return asin(input);
    770     case ATAN:
    771       return atan(input);
    772     case COS:
    773       return fast_cos(input);
    774     case EXP:
    775       return exp(input);
    776     case LOG:
    777       return fast_log(input);
    778     case SIN:
    779       return fast_sin(input);
    780     case TAN:
    781       return fast_tan(input);
    782     default:
    783       return 0.0;  // Never happens.
    784   }
    785 }
    786 
    787 
    788 MaybeObject* TranscendentalCache::SubCache::Get(double input) {
    789   Converter c;
    790   c.dbl = input;
    791   int hash = Hash(c);
    792   Element e = elements_[hash];
    793   if (e.in[0] == c.integers[0] &&
    794       e.in[1] == c.integers[1]) {
    795     ASSERT(e.output != NULL);
    796     isolate_->counters()->transcendental_cache_hit()->Increment();
    797     return e.output;
    798   }
    799   double answer = Calculate(input);
    800   isolate_->counters()->transcendental_cache_miss()->Increment();
    801   Object* heap_number;
    802   { MaybeObject* maybe_heap_number =
    803         isolate_->heap()->AllocateHeapNumber(answer);
    804     if (!maybe_heap_number->ToObject(&heap_number)) return maybe_heap_number;
    805   }
    806   elements_[hash].in[0] = c.integers[0];
    807   elements_[hash].in[1] = c.integers[1];
    808   elements_[hash].output = heap_number;
    809   return heap_number;
    810 }
    811 
    812 
    813 AlwaysAllocateScope::AlwaysAllocateScope() {
    814   // We shouldn't hit any nested scopes, because that requires
    815   // non-handle code to call handle code. The code still works but
    816   // performance will degrade, so we want to catch this situation
    817   // in debug mode.
    818   Isolate* isolate = Isolate::Current();
    819   ASSERT(isolate->heap()->always_allocate_scope_depth_ == 0);
    820   isolate->heap()->always_allocate_scope_depth_++;
    821 }
    822 
    823 
    824 AlwaysAllocateScope::~AlwaysAllocateScope() {
    825   Isolate* isolate = Isolate::Current();
    826   isolate->heap()->always_allocate_scope_depth_--;
    827   ASSERT(isolate->heap()->always_allocate_scope_depth_ == 0);
    828 }
    829 
    830 
    831 #ifdef VERIFY_HEAP
    832 NoWeakObjectVerificationScope::NoWeakObjectVerificationScope() {
    833   Isolate* isolate = Isolate::Current();
    834   isolate->heap()->no_weak_object_verification_scope_depth_++;
    835 }
    836 
    837 
    838 NoWeakObjectVerificationScope::~NoWeakObjectVerificationScope() {
    839   Isolate* isolate = Isolate::Current();
    840   isolate->heap()->no_weak_object_verification_scope_depth_--;
    841 }
    842 #endif
    843 
    844 
    845 void VerifyPointersVisitor::VisitPointers(Object** start, Object** end) {
    846   for (Object** current = start; current < end; current++) {
    847     if ((*current)->IsHeapObject()) {
    848       HeapObject* object = HeapObject::cast(*current);
    849       CHECK(object->GetIsolate()->heap()->Contains(object));
    850       CHECK(object->map()->IsMap());
    851     }
    852   }
    853 }
    854 
    855 
    856 double GCTracer::SizeOfHeapObjects() {
    857   return (static_cast<double>(heap_->SizeOfObjects())) / MB;
    858 }
    859 
    860 
    861 DisallowAllocationFailure::DisallowAllocationFailure() {
    862 #ifdef DEBUG
    863   Isolate* isolate = Isolate::Current();
    864   old_state_ = isolate->heap()->disallow_allocation_failure_;
    865   isolate->heap()->disallow_allocation_failure_ = true;
    866 #endif
    867 }
    868 
    869 
    870 DisallowAllocationFailure::~DisallowAllocationFailure() {
    871 #ifdef DEBUG
    872   Isolate* isolate = Isolate::Current();
    873   isolate->heap()->disallow_allocation_failure_ = old_state_;
    874 #endif
    875 }
    876 
    877 
    878 } }  // namespace v8::internal
    879 
    880 #endif  // V8_HEAP_INL_H_
    881