heap.cc.svn-base

Google浏览器V8内核代码

        // Record the object's address at the top of the to space, to allow
        // it to be swept by the scavenger.
        promoted_top -= kPointerSize;
        Memory::Object_at(promoted_top) = *p;
      } else {
#ifdef DEBUG
        // Objects promoted to the data space should not have pointers to
        // new space.
        VerifyNonPointerSpacePointersVisitor v;
        (*p)->Iterate(&v);
#endif
      }
      return;
    }
  }

  // The object should remain in new space or the old space allocation failed.
  result = new_space_->AllocateRaw(object_size);
  // Failed allocation at this point is utterly unexpected.
  ASSERT(!result->IsFailure());
  *p = MigrateObject(p, HeapObject::cast(result), object_size);
}


Object* Heap::AllocatePartialMap(InstanceType instance_type,
                                 int instance_size) {
  Object* result = AllocateRawMap(Map::kSize);
  if (result->IsFailure()) return result;

  // Map::cast cannot be used due to uninitialized map field.
  reinterpret_cast<Map*>(result)->set_map(meta_map());
  reinterpret_cast<Map*>(result)->set_instance_type(instance_type);
  reinterpret_cast<Map*>(result)->set_instance_size(instance_size);
  reinterpret_cast<Map*>(result)->set_unused_property_fields(0);
  return result;
}


Object* Heap::AllocateMap(InstanceType instance_type, int instance_size) {
  Object* result = AllocateRawMap(Map::kSize);
  if (result->IsFailure()) return result;

  Map* map = reinterpret_cast<Map*>(result);
  map->set_map(meta_map());
  map->set_instance_type(instance_type);
  map->set_prototype(null_value());
  map->set_constructor(null_value());
  map->set_instance_size(instance_size);
  map->set_instance_descriptors(empty_descriptor_array());
  map->set_code_cache(empty_fixed_array());
  map->set_unused_property_fields(0);
  map->set_bit_field(0);
  return map;
}


bool Heap::CreateInitialMaps() {
  Object* obj = AllocatePartialMap(MAP_TYPE, Map::kSize);
  if (obj->IsFailure()) return false;

  // Map::cast cannot be used due to uninitialized map field.
  meta_map_ = reinterpret_cast<Map*>(obj);
  meta_map()->set_map(meta_map());

  obj = AllocatePartialMap(FIXED_ARRAY_TYPE, Array::kHeaderSize);
  if (obj->IsFailure()) return false;
  fixed_array_map_ = Map::cast(obj);

  obj = AllocatePartialMap(ODDBALL_TYPE, Oddball::kSize);
  if (obj->IsFailure()) return false;
  oddball_map_ = Map::cast(obj);

  // Allocate the empty array
  obj = AllocateEmptyFixedArray();
  if (obj->IsFailure()) return false;
  empty_fixed_array_ = FixedArray::cast(obj);

  obj = Allocate(oddball_map(), OLD_DATA_SPACE);
  if (obj->IsFailure()) return false;
  null_value_ = obj;

  // Allocate the empty descriptor array.  AllocateMap can now be used.
  obj = AllocateEmptyFixedArray();
  if (obj->IsFailure()) return false;
  // There is a check against empty_descriptor_array() in cast().
  empty_descriptor_array_ = reinterpret_cast<DescriptorArray*>(obj);

  // Fix the instance_descriptors for the existing maps.
  meta_map()->set_instance_descriptors(empty_descriptor_array());
  meta_map()->set_code_cache(empty_fixed_array());

  fixed_array_map()->set_instance_descriptors(empty_descriptor_array());
  fixed_array_map()->set_code_cache(empty_fixed_array());

  oddball_map()->set_instance_descriptors(empty_descriptor_array());
  oddball_map()->set_code_cache(empty_fixed_array());

  // Fix prototype object for existing maps.
  meta_map()->set_prototype(null_value());
  meta_map()->set_constructor(null_value());

  fixed_array_map()->set_prototype(null_value());
  fixed_array_map()->set_constructor(null_value());
  oddball_map()->set_prototype(null_value());
  oddball_map()->set_constructor(null_value());

  obj = AllocateMap(HEAP_NUMBER_TYPE, HeapNumber::kSize);
  if (obj->IsFailure()) return false;
  heap_number_map_ = Map::cast(obj);

  obj = AllocateMap(PROXY_TYPE, Proxy::kSize);
  if (obj->IsFailure()) return false;
  proxy_map_ = Map::cast(obj);

#define ALLOCATE_STRING_MAP(type, size, name)   \
    obj = AllocateMap(type, size);              \
    if (obj->IsFailure()) return false;         \
    name##_map_ = Map::cast(obj);
  STRING_TYPE_LIST(ALLOCATE_STRING_MAP);
#undef ALLOCATE_STRING_MAP

  obj = AllocateMap(SHORT_STRING_TYPE, TwoByteString::kHeaderSize);
  if (obj->IsFailure()) return false;
  undetectable_short_string_map_ = Map::cast(obj);
  undetectable_short_string_map_->set_is_undetectable();

  obj = AllocateMap(MEDIUM_STRING_TYPE, TwoByteString::kHeaderSize);
  if (obj->IsFailure()) return false;
  undetectable_medium_string_map_ = Map::cast(obj);
  undetectable_medium_string_map_->set_is_undetectable();

  obj = AllocateMap(LONG_STRING_TYPE, TwoByteString::kHeaderSize);
  if (obj->IsFailure()) return false;
  undetectable_long_string_map_ = Map::cast(obj);
  undetectable_long_string_map_->set_is_undetectable();

  obj = AllocateMap(SHORT_ASCII_STRING_TYPE, AsciiString::kHeaderSize);
  if (obj->IsFailure()) return false;
  undetectable_short_ascii_string_map_ = Map::cast(obj);
  undetectable_short_ascii_string_map_->set_is_undetectable();

  obj = AllocateMap(MEDIUM_ASCII_STRING_TYPE, AsciiString::kHeaderSize);
  if (obj->IsFailure()) return false;
  undetectable_medium_ascii_string_map_ = Map::cast(obj);
  undetectable_medium_ascii_string_map_->set_is_undetectable();

  obj = AllocateMap(LONG_ASCII_STRING_TYPE, AsciiString::kHeaderSize);
  if (obj->IsFailure()) return false;
  undetectable_long_ascii_string_map_ = Map::cast(obj);
  undetectable_long_ascii_string_map_->set_is_undetectable();

  obj = AllocateMap(BYTE_ARRAY_TYPE, Array::kHeaderSize);
  if (obj->IsFailure()) return false;
  byte_array_map_ = Map::cast(obj);

  obj = AllocateMap(CODE_TYPE, Code::kHeaderSize);
  if (obj->IsFailure()) return false;
  code_map_ = Map::cast(obj);

  obj = AllocateMap(FILLER_TYPE, kPointerSize);
  if (obj->IsFailure()) return false;
  one_word_filler_map_ = Map::cast(obj);

  obj = AllocateMap(FILLER_TYPE, 2 * kPointerSize);
  if (obj->IsFailure()) return false;
  two_word_filler_map_ = Map::cast(obj);

#define ALLOCATE_STRUCT_MAP(NAME, Name, name)      \
  obj = AllocateMap(NAME##_TYPE, Name::kSize);     \
  if (obj->IsFailure()) return false;              \
  name##_map_ = Map::cast(obj);
  STRUCT_LIST(ALLOCATE_STRUCT_MAP)
#undef ALLOCATE_STRUCT_MAP

  obj = AllocateMap(FIXED_ARRAY_TYPE, HeapObject::kHeaderSize);
  if (obj->IsFailure()) return false;
  hash_table_map_ = Map::cast(obj);

  obj = AllocateMap(FIXED_ARRAY_TYPE, HeapObject::kHeaderSize);
  if (obj->IsFailure()) return false;
  context_map_ = Map::cast(obj);

  obj = AllocateMap(FIXED_ARRAY_TYPE, HeapObject::kHeaderSize);
  if (obj->IsFailure()) return false;
  global_context_map_ = Map::cast(obj);

  obj = AllocateMap(JS_FUNCTION_TYPE, JSFunction::kSize);
  if (obj->IsFailure()) return false;
  boilerplate_function_map_ = Map::cast(obj);

  obj = AllocateMap(SHARED_FUNCTION_INFO_TYPE, SharedFunctionInfo::kSize);
  if (obj->IsFailure()) return false;
  shared_function_info_map_ = Map::cast(obj);

  ASSERT(!Heap::InNewSpace(Heap::empty_fixed_array()));
  return true;
}


Object* Heap::AllocateHeapNumber(double value, PretenureFlag pretenure) {
  // Statically ensure that it is safe to allocate heap numbers in paged
  // spaces.
  STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
  AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
  Object* result = AllocateRaw(HeapNumber::kSize, space);
  if (result->IsFailure()) return result;

  HeapObject::cast(result)->set_map(heap_number_map());
  HeapNumber::cast(result)->set_value(value);
  return result;
}


Object* Heap::AllocateHeapNumber(double value) {
  // This version of AllocateHeapNumber is optimized for
  // allocation in new space.
  STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
  ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
  Object* result = new_space_->AllocateRaw(HeapNumber::kSize);
  if (result->IsFailure()) return result;
  HeapObject::cast(result)->set_map(heap_number_map());
  HeapNumber::cast(result)->set_value(value);
  return result;
}


Object* Heap::CreateOddball(Map* map,
                            const char* to_string,
                            Object* to_number) {
  Object* result = Allocate(map, OLD_DATA_SPACE);
  if (result->IsFailure()) return result;
  return Oddball::cast(result)->Initialize(to_string, to_number);
}


bool Heap::CreateApiObjects() {
  Object* obj;

  obj = AllocateMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
  if (obj->IsFailure()) return false;
  neander_map_ = Map::cast(obj);

  obj = Heap::AllocateJSObjectFromMap(neander_map_);
  if (obj->IsFailure()) return false;
  Object* elements = AllocateFixedArray(2);
  if (elements->IsFailure()) return false;
  FixedArray::cast(elements)->set(0, Smi::FromInt(0));
  JSObject::cast(obj)->set_elements(FixedArray::cast(elements));
  message_listeners_ = JSObject::cast(obj);

  obj = Heap::AllocateJSObjectFromMap(neander_map_);
  if (obj->IsFailure()) return false;
  elements = AllocateFixedArray(2);
  if (elements->IsFailure()) return false;
  FixedArray::cast(elements)->set(0, Smi::FromInt(0));
  JSObject::cast(obj)->set_elements(FixedArray::cast(elements));
  debug_event_listeners_ = JSObject::cast(obj);

  return true;
}

void Heap::CreateFixedStubs() {
  // Here we create roots for fixed stubs. They are needed at GC
  // for cooking and uncooking (check out frames.cc).
  // The eliminates the need for doing dictionary lookup in the
  // stub cache for these stubs.
  HandleScope scope;
  {
    CEntryStub stub;
    c_entry_code_ = *stub.GetCode();
  }
  {
    CEntryDebugBreakStub stub;
    c_entry_debug_break_code_ = *stub.GetCode();
  }
  {
    JSEntryStub stub;
    js_entry_code_ = *stub.GetCode();
  }
  {
    JSConstructEntryStub stub;
    js_construct_entry_code_ = *stub.GetCode();
  }
}


bool Heap::CreateInitialObjects() {
  Object* obj;

  // The -0 value must be set before NumberFromDouble works.
  obj = AllocateHeapNumber(-0.0, TENURED);
  if (obj->IsFailure()) return false;
  minus_zero_value_ = obj;
  ASSERT(signbit(minus_zero_value_->Number()) != 0);

  obj = AllocateHeapNumber(OS::nan_value(), TENURED);
  if (obj->IsFailure()) return false;
  nan_value_ = obj;

  obj = Allocate(oddball_map(), OLD_DATA_SPACE);
  if (obj->IsFailure()) return false;
  undefined_value_ = obj;
  ASSERT(!InNewSpace(undefined_value()));

  // Allocate initial symbol table.
  obj = SymbolTable::Allocate(kInitialSymbolTableSize);
  if (obj->IsFailure()) return false;
  symbol_table_ = obj;

  // Assign the print strings for oddballs after creating symboltable.
  Object* symbol = LookupAsciiSymbol("undefined");
  if (symbol->IsFailure()) return false;
  Oddball::cast(undefined_value_)->set_to_string(String::cast(symbol));
  Oddball::cast(undefined_value_)->set_to_number(nan_value_);

  // Assign the print strings for oddballs after creating symboltable.
  symbol = LookupAsciiSymbol("null");
  if (symbol->IsFailure()) return false;
  Oddball::cast(null_value_)->set_to_string(String::cast(symbol));
  Oddball::cast(null_value_)->set_to_number(Smi::FromInt(0));

  // Allocate the null_value
  obj = Oddball::cast(null_value())->Initialize("null", Smi::FromInt(0));
  if (obj->IsFailure()) return false;

  obj = CreateOddball(oddball_map(), "true", Smi::FromInt(1));
  if (obj->IsFailure()) return false;
  true_value_ = obj;

  obj = CreateOddball(oddball_map(), "false", Smi::FromInt(0));
  if (obj->IsFailure()) return false;
  false_value_ = obj;

  obj = CreateOddball(oddball_map(), "hole", Smi::FromInt(-1));
  if (obj->IsFailure()) return false;
  the_hole_value_ = obj;

  // Allocate the empty string.
  obj = AllocateRawAsciiString(0, TENURED);
  if (obj->IsFailure()) return false;
  empty_string_ = String::cast(obj);

#define SYMBOL_INITIALIZE(name, string)                 \
  obj = LookupAsciiSymbol(string);                      \
  if (obj->IsFailure()) return false;                   \
  (name##_) = String::cast(obj);
  SYMBOL_LIST(SYMBOL_INITIALIZE)
#undef SYMBOL_INITIALIZE

  // Allocate the proxy for __proto__.
  obj = AllocateProxy((Address) &Accessors::ObjectPrototype);
  if (obj->IsFailure()) return false;
  prototype_accessors_ = Proxy::cast(obj);

  // Allocate the code_stubs dictionary.
  obj = Dictionary::Allocate(4);
  if (obj->IsFailure()) return false;
  code_stubs_ = Dictionary::cast(obj);

  // Allocate the non_monomorphic_cache used in stub-cache.cc
  obj = Dictionary::Allocate(4);
  if (obj->IsFailure()) return false;
  non_monomorphic_cache_ =  Dictionary::cast(obj);

  CreateFixedStubs();

  // Allocate the number->string conversion cache
  obj = AllocateFixedArray(kNumberStringCacheSize * 2);
  if (obj->IsFailure()) return false;
  number_string_cache_ = FixedArray::cast(obj);

  // Allocate cache for single character strings.
  obj = AllocateFixedArray(String::kMaxAsciiCharCode+1);
  if (obj->IsFailure()) return false;
  single_character_string_cache_ = FixedArray::cast(obj);

  // Allocate cache for external strings pointing to native source code.
  obj = AllocateFixedArray(Natives::GetBuiltinsCount());
  if (obj->IsFailure()) return false;
  natives_source_cache_ = FixedArray::cast(obj);

  // Initialize compilation cache.
  CompilationCache::Clear();

  return true;
}


static inline int double_get_hash(double d) {
  DoubleRepresentation rep(d);
  return ((static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32)) &
          (Heap::kNumberStringCacheSize - 1));
}


static inline int smi_get_hash(Smi* smi) {
  return (smi->value() & (Heap::kNumberStringCacheSize - 1));
}