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// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_OBJECTS_H_
#define V8_OBJECTS_H_
#include <iosfwd>
#include <memory>
#include "src/assert-scope.h"
#include "src/bailout-reason.h"
#include "src/base/bits.h"
#include "src/base/flags.h"
#include "src/builtins/builtins-definitions.h"
#include "src/checks.h"
#include "src/elements-kind.h"
#include "src/field-index.h"
#include "src/flags.h"
#include "src/list.h"
#include "src/messages.h"
#include "src/property-details.h"
#include "src/unicode-decoder.h"
#include "src/unicode.h"
#include "src/zone/zone.h"
#if V8_TARGET_ARCH_ARM
#include "src/arm/constants-arm.h" // NOLINT
#elif V8_TARGET_ARCH_ARM64
#include "src/arm64/constants-arm64.h" // NOLINT
#elif V8_TARGET_ARCH_MIPS
#include "src/mips/constants-mips.h" // NOLINT
#elif V8_TARGET_ARCH_MIPS64
#include "src/mips64/constants-mips64.h" // NOLINT
#elif V8_TARGET_ARCH_PPC
#include "src/ppc/constants-ppc.h" // NOLINT
#elif V8_TARGET_ARCH_S390
#include "src/s390/constants-s390.h" // NOLINT
#endif
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
//
// Most object types in the V8 JavaScript are described in this file.
//
// Inheritance hierarchy:
// - Object
// - Smi (immediate small integer)
// - HeapObject (superclass for everything allocated in the heap)
// - JSReceiver (suitable for property access)
// - JSObject
// - JSArray
// - JSArrayBuffer
// - JSArrayBufferView
// - JSTypedArray
// - JSDataView
// - JSBoundFunction
// - JSCollection
// - JSSet
// - JSMap
// - JSStringIterator
// - JSSetIterator
// - JSMapIterator
// - JSWeakCollection
// - JSWeakMap
// - JSWeakSet
// - JSRegExp
// - JSFunction
// - JSGeneratorObject
// - JSGlobalObject
// - JSGlobalProxy
// - JSValue
// - JSDate
// - JSMessageObject
// - JSModuleNamespace
// - JSProxy
// - FixedArrayBase
// - ByteArray
// - BytecodeArray
// - FixedArray
// - DescriptorArray
// - FrameArray
// - HashTable
// - Dictionary
// - StringTable
// - StringSet
// - CompilationCacheTable
// - CodeCacheHashTable
// - MapCache
// - OrderedHashTable
// - OrderedHashSet
// - OrderedHashMap
// - Context
// - FeedbackMetadata
// - FeedbackVector
// - TemplateList
// - TransitionArray
// - ScopeInfo
// - ModuleInfo
// - ScriptContextTable
// - WeakFixedArray
// - FixedDoubleArray
// - Name
// - String
// - SeqString
// - SeqOneByteString
// - SeqTwoByteString
// - SlicedString
// - ConsString
// - ThinString
// - ExternalString
// - ExternalOneByteString
// - ExternalTwoByteString
// - InternalizedString
// - SeqInternalizedString
// - SeqOneByteInternalizedString
// - SeqTwoByteInternalizedString
// - ConsInternalizedString
// - ExternalInternalizedString
// - ExternalOneByteInternalizedString
// - ExternalTwoByteInternalizedString
// - Symbol
// - HeapNumber
// - Cell
// - PropertyCell
// - Code
// - AbstractCode, a wrapper around Code or BytecodeArray
// - Map
// - Oddball
// - Foreign
// - SharedFunctionInfo
// - Struct
// - AccessorInfo
// - PromiseResolveThenableJobInfo
// - PromiseReactionJobInfo
// - AccessorPair
// - AccessCheckInfo
// - InterceptorInfo
// - CallHandlerInfo
// - TemplateInfo
// - FunctionTemplateInfo
// - ObjectTemplateInfo
// - Script
// - DebugInfo
// - BreakPointInfo
// - StackFrameInfo
// - SourcePositionTableWithFrameCache
// - CodeCache
// - PrototypeInfo
// - Module
// - ModuleInfoEntry
// - WeakCell
//
// Formats of Object*:
// Smi: [31 bit signed int] 0
// HeapObject: [32 bit direct pointer] (4 byte aligned) | 01
namespace v8 {
namespace internal {
struct InliningPosition;
enum KeyedAccessStoreMode {
STANDARD_STORE,
STORE_TRANSITION_TO_OBJECT,
STORE_TRANSITION_TO_DOUBLE,
STORE_AND_GROW_NO_TRANSITION,
STORE_AND_GROW_TRANSITION_TO_OBJECT,
STORE_AND_GROW_TRANSITION_TO_DOUBLE,
STORE_NO_TRANSITION_IGNORE_OUT_OF_BOUNDS,
STORE_NO_TRANSITION_HANDLE_COW
};
enum MutableMode {
MUTABLE,
IMMUTABLE
};
static inline bool IsTransitionStoreMode(KeyedAccessStoreMode store_mode) {
return store_mode == STORE_TRANSITION_TO_OBJECT ||
store_mode == STORE_TRANSITION_TO_DOUBLE ||
store_mode == STORE_AND_GROW_TRANSITION_TO_OBJECT ||
store_mode == STORE_AND_GROW_TRANSITION_TO_DOUBLE;
}
static inline KeyedAccessStoreMode GetNonTransitioningStoreMode(
KeyedAccessStoreMode store_mode) {
if (store_mode >= STORE_NO_TRANSITION_IGNORE_OUT_OF_BOUNDS) {
return store_mode;
}
if (store_mode >= STORE_AND_GROW_NO_TRANSITION) {
return STORE_AND_GROW_NO_TRANSITION;
}
return STANDARD_STORE;
}
static inline bool IsGrowStoreMode(KeyedAccessStoreMode store_mode) {
return store_mode >= STORE_AND_GROW_NO_TRANSITION &&
store_mode <= STORE_AND_GROW_TRANSITION_TO_DOUBLE;
}
enum IcCheckType { ELEMENT, PROPERTY };
// SKIP_WRITE_BARRIER skips the write barrier.
// UPDATE_WEAK_WRITE_BARRIER skips the marking part of the write barrier and
// only performs the generational part.
// UPDATE_WRITE_BARRIER is doing the full barrier, marking and generational.
enum WriteBarrierMode {
SKIP_WRITE_BARRIER,
UPDATE_WEAK_WRITE_BARRIER,
UPDATE_WRITE_BARRIER
};
// PropertyNormalizationMode is used to specify whether to keep
// inobject properties when normalizing properties of a JSObject.
enum PropertyNormalizationMode {
CLEAR_INOBJECT_PROPERTIES,
KEEP_INOBJECT_PROPERTIES
};
// Indicates how aggressively the prototype should be optimized. FAST_PROTOTYPE
// will give the fastest result by tailoring the map to the prototype, but that
// will cause polymorphism with other objects. REGULAR_PROTOTYPE is to be used
// (at least for now) when dynamically modifying the prototype chain of an
// object using __proto__ or Object.setPrototypeOf.
enum PrototypeOptimizationMode { REGULAR_PROTOTYPE, FAST_PROTOTYPE };
// Indicates whether transitions can be added to a source map or not.
enum TransitionFlag {
INSERT_TRANSITION,
OMIT_TRANSITION
};
// Indicates whether the transition is simple: the target map of the transition
// either extends the current map with a new property, or it modifies the
// property that was added last to the current map.
enum SimpleTransitionFlag {
SIMPLE_PROPERTY_TRANSITION,
PROPERTY_TRANSITION,
SPECIAL_TRANSITION
};
// Indicates whether we are only interested in the descriptors of a particular
// map, or in all descriptors in the descriptor array.
enum DescriptorFlag {
ALL_DESCRIPTORS,
OWN_DESCRIPTORS
};
// ICs store extra state in a Code object. The default extra state is
// kNoExtraICState.
typedef int ExtraICState;
static const ExtraICState kNoExtraICState = 0;
// Instance size sentinel for objects of variable size.
const int kVariableSizeSentinel = 0;
// We may store the unsigned bit field as signed Smi value and do not
// use the sign bit.
const int kStubMajorKeyBits = 8;
const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;
// All Maps have a field instance_type containing a InstanceType.
// It describes the type of the instances.
//
// As an example, a JavaScript object is a heap object and its map
// instance_type is JS_OBJECT_TYPE.
//
// The names of the string instance types are intended to systematically
// mirror their encoding in the instance_type field of the map. The default
// encoding is considered TWO_BYTE. It is not mentioned in the name. ONE_BYTE
// encoding is mentioned explicitly in the name. Likewise, the default
// representation is considered sequential. It is not mentioned in the
// name. The other representations (e.g. CONS, EXTERNAL) are explicitly
// mentioned. Finally, the string is either a STRING_TYPE (if it is a normal
// string) or a INTERNALIZED_STRING_TYPE (if it is a internalized string).
//
// NOTE: The following things are some that depend on the string types having
// instance_types that are less than those of all other types:
// HeapObject::Size, HeapObject::IterateBody, the typeof operator, and
// Object::IsString.
//
// NOTE: Everything following JS_VALUE_TYPE is considered a
// JSObject for GC purposes. The first four entries here have typeof
// 'object', whereas JS_FUNCTION_TYPE has typeof 'function'.
#define INSTANCE_TYPE_LIST(V) \
V(INTERNALIZED_STRING_TYPE) \
V(EXTERNAL_INTERNALIZED_STRING_TYPE) \
V(ONE_BYTE_INTERNALIZED_STRING_TYPE) \
V(EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE) \
V(EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE) \
V(SHORT_EXTERNAL_INTERNALIZED_STRING_TYPE) \
V(SHORT_EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE) \
V(SHORT_EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE) \
V(STRING_TYPE) \
V(CONS_STRING_TYPE) \
V(EXTERNAL_STRING_TYPE) \
V(SLICED_STRING_TYPE) \
V(THIN_STRING_TYPE) \
V(ONE_BYTE_STRING_TYPE) \
V(CONS_ONE_BYTE_STRING_TYPE) \
V(EXTERNAL_ONE_BYTE_STRING_TYPE) \
V(SLICED_ONE_BYTE_STRING_TYPE) \
V(THIN_ONE_BYTE_STRING_TYPE) \
V(EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE) \
V(SHORT_EXTERNAL_STRING_TYPE) \
V(SHORT_EXTERNAL_ONE_BYTE_STRING_TYPE) \
V(SHORT_EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE) \
\
V(SYMBOL_TYPE) \
V(HEAP_NUMBER_TYPE) \
V(ODDBALL_TYPE) \
\
V(MAP_TYPE) \
V(CODE_TYPE) \
V(MUTABLE_HEAP_NUMBER_TYPE) \
V(FOREIGN_TYPE) \
V(BYTE_ARRAY_TYPE) \
V(BYTECODE_ARRAY_TYPE) \
V(FREE_SPACE_TYPE) \
\
V(FIXED_INT8_ARRAY_TYPE) \
V(FIXED_UINT8_ARRAY_TYPE) \
V(FIXED_INT16_ARRAY_TYPE) \
V(FIXED_UINT16_ARRAY_TYPE) \
V(FIXED_INT32_ARRAY_TYPE) \
V(FIXED_UINT32_ARRAY_TYPE) \
V(FIXED_FLOAT32_ARRAY_TYPE) \
V(FIXED_FLOAT64_ARRAY_TYPE) \
V(FIXED_UINT8_CLAMPED_ARRAY_TYPE) \
\
V(FIXED_DOUBLE_ARRAY_TYPE) \
V(FILLER_TYPE) \
\
V(ACCESSOR_INFO_TYPE) \
V(ACCESSOR_PAIR_TYPE) \
V(ACCESS_CHECK_INFO_TYPE) \
V(INTERCEPTOR_INFO_TYPE) \
V(FUNCTION_TEMPLATE_INFO_TYPE) \
V(OBJECT_TEMPLATE_INFO_TYPE) \
V(ALLOCATION_SITE_TYPE) \
V(ALLOCATION_MEMENTO_TYPE) \
V(SCRIPT_TYPE) \
V(ALIASED_ARGUMENTS_ENTRY_TYPE) \
V(PROMISE_RESOLVE_THENABLE_JOB_INFO_TYPE) \
V(PROMISE_REACTION_JOB_INFO_TYPE) \
V(DEBUG_INFO_TYPE) \
V(STACK_FRAME_INFO_TYPE) \
V(PROTOTYPE_INFO_TYPE) \
V(TUPLE2_TYPE) \
V(TUPLE3_TYPE) \
V(CONTEXT_EXTENSION_TYPE) \
V(MODULE_TYPE) \
V(MODULE_INFO_ENTRY_TYPE) \
V(ASYNC_GENERATOR_REQUEST_TYPE) \
V(FIXED_ARRAY_TYPE) \
V(TRANSITION_ARRAY_TYPE) \
V(SHARED_FUNCTION_INFO_TYPE) \
V(CELL_TYPE) \
V(WEAK_CELL_TYPE) \
V(PROPERTY_CELL_TYPE) \
/* TODO(yangguo): these padding types are for ABI stability. Remove after*/ \
/* version 6.0 branch, or replace them when there is demand for new types.*/ \
V(PADDING_TYPE_1) \
V(PADDING_TYPE_2) \
V(PADDING_TYPE_3) \
V(PADDING_TYPE_4) \
\
V(JS_PROXY_TYPE) \
V(JS_GLOBAL_OBJECT_TYPE) \
V(JS_GLOBAL_PROXY_TYPE) \
V(JS_SPECIAL_API_OBJECT_TYPE) \
V(JS_VALUE_TYPE) \
V(JS_MESSAGE_OBJECT_TYPE) \
V(JS_DATE_TYPE) \
V(JS_API_OBJECT_TYPE) \
V(JS_OBJECT_TYPE) \
V(JS_ARGUMENTS_TYPE) \
V(JS_CONTEXT_EXTENSION_OBJECT_TYPE) \
V(JS_GENERATOR_OBJECT_TYPE) \
V(JS_ASYNC_GENERATOR_OBJECT_TYPE) \
V(JS_MODULE_NAMESPACE_TYPE) \
V(JS_ARRAY_TYPE) \
V(JS_ARRAY_BUFFER_TYPE) \
V(JS_TYPED_ARRAY_TYPE) \
V(JS_DATA_VIEW_TYPE) \
V(JS_SET_TYPE) \
V(JS_MAP_TYPE) \
V(JS_SET_ITERATOR_TYPE) \
V(JS_MAP_ITERATOR_TYPE) \
V(JS_WEAK_MAP_TYPE) \
V(JS_WEAK_SET_TYPE) \
V(JS_PROMISE_CAPABILITY_TYPE) \
V(JS_PROMISE_TYPE) \
V(JS_REGEXP_TYPE) \
V(JS_ERROR_TYPE) \
V(JS_ASYNC_FROM_SYNC_ITERATOR_TYPE) \
V(JS_STRING_ITERATOR_TYPE) \
\
V(JS_TYPED_ARRAY_KEY_ITERATOR_TYPE) \
V(JS_FAST_ARRAY_KEY_ITERATOR_TYPE) \
V(JS_GENERIC_ARRAY_KEY_ITERATOR_TYPE) \
\
V(JS_UINT8_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_INT8_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_UINT16_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_INT16_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_UINT32_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_INT32_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FLOAT32_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FLOAT64_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_UINT8_CLAMPED_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
\
V(JS_FAST_SMI_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_HOLEY_SMI_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_HOLEY_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_DOUBLE_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_HOLEY_DOUBLE_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
V(JS_GENERIC_ARRAY_KEY_VALUE_ITERATOR_TYPE) \
\
V(JS_UINT8_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_INT8_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_UINT16_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_INT16_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_UINT32_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_INT32_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FLOAT32_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FLOAT64_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_UINT8_CLAMPED_ARRAY_VALUE_ITERATOR_TYPE) \
\
V(JS_FAST_SMI_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_HOLEY_SMI_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_HOLEY_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_DOUBLE_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_FAST_HOLEY_DOUBLE_ARRAY_VALUE_ITERATOR_TYPE) \
V(JS_GENERIC_ARRAY_VALUE_ITERATOR_TYPE) \
\
V(JS_BOUND_FUNCTION_TYPE) \
V(JS_FUNCTION_TYPE)
// Since string types are not consecutive, this macro is used to
// iterate over them.
#define STRING_TYPE_LIST(V) \
V(STRING_TYPE, kVariableSizeSentinel, string, String) \
V(ONE_BYTE_STRING_TYPE, kVariableSizeSentinel, one_byte_string, \
OneByteString) \
V(CONS_STRING_TYPE, ConsString::kSize, cons_string, ConsString) \
V(CONS_ONE_BYTE_STRING_TYPE, ConsString::kSize, cons_one_byte_string, \
ConsOneByteString) \
V(SLICED_STRING_TYPE, SlicedString::kSize, sliced_string, SlicedString) \
V(SLICED_ONE_BYTE_STRING_TYPE, SlicedString::kSize, sliced_one_byte_string, \
SlicedOneByteString) \
V(EXTERNAL_STRING_TYPE, ExternalTwoByteString::kSize, external_string, \
ExternalString) \
V(EXTERNAL_ONE_BYTE_STRING_TYPE, ExternalOneByteString::kSize, \
external_one_byte_string, ExternalOneByteString) \
V(EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE, ExternalTwoByteString::kSize, \
external_string_with_one_byte_data, ExternalStringWithOneByteData) \
V(SHORT_EXTERNAL_STRING_TYPE, ExternalTwoByteString::kShortSize, \
short_external_string, ShortExternalString) \
V(SHORT_EXTERNAL_ONE_BYTE_STRING_TYPE, ExternalOneByteString::kShortSize, \
short_external_one_byte_string, ShortExternalOneByteString) \
V(SHORT_EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE, \
ExternalTwoByteString::kShortSize, \
short_external_string_with_one_byte_data, \
ShortExternalStringWithOneByteData) \
\
V(INTERNALIZED_STRING_TYPE, kVariableSizeSentinel, internalized_string, \
InternalizedString) \
V(ONE_BYTE_INTERNALIZED_STRING_TYPE, kVariableSizeSentinel, \
one_byte_internalized_string, OneByteInternalizedString) \
V(EXTERNAL_INTERNALIZED_STRING_TYPE, ExternalTwoByteString::kSize, \
external_internalized_string, ExternalInternalizedString) \
V(EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE, ExternalOneByteString::kSize, \
external_one_byte_internalized_string, ExternalOneByteInternalizedString) \
V(EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE, \
ExternalTwoByteString::kSize, \
external_internalized_string_with_one_byte_data, \
ExternalInternalizedStringWithOneByteData) \
V(SHORT_EXTERNAL_INTERNALIZED_STRING_TYPE, \
ExternalTwoByteString::kShortSize, short_external_internalized_string, \
ShortExternalInternalizedString) \
V(SHORT_EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE, \
ExternalOneByteString::kShortSize, \
short_external_one_byte_internalized_string, \
ShortExternalOneByteInternalizedString) \
V(SHORT_EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE, \
ExternalTwoByteString::kShortSize, \
short_external_internalized_string_with_one_byte_data, \
ShortExternalInternalizedStringWithOneByteData) \
V(THIN_STRING_TYPE, ThinString::kSize, thin_string, ThinString) \
V(THIN_ONE_BYTE_STRING_TYPE, ThinString::kSize, thin_one_byte_string, \
ThinOneByteString)
// A struct is a simple object a set of object-valued fields. Including an
// object type in this causes the compiler to generate most of the boilerplate
// code for the class including allocation and garbage collection routines,
// casts and predicates. All you need to define is the class, methods and
// object verification routines. Easy, no?
//
// Note that for subtle reasons related to the ordering or numerical values of
// type tags, elements in this list have to be added to the INSTANCE_TYPE_LIST
// manually.
#define STRUCT_LIST(V) \
V(ACCESSOR_INFO, AccessorInfo, accessor_info) \
V(ACCESSOR_PAIR, AccessorPair, accessor_pair) \
V(ACCESS_CHECK_INFO, AccessCheckInfo, access_check_info) \
V(INTERCEPTOR_INFO, InterceptorInfo, interceptor_info) \
V(FUNCTION_TEMPLATE_INFO, FunctionTemplateInfo, function_template_info) \
V(OBJECT_TEMPLATE_INFO, ObjectTemplateInfo, object_template_info) \
V(ALLOCATION_SITE, AllocationSite, allocation_site) \
V(ALLOCATION_MEMENTO, AllocationMemento, allocation_memento) \
V(SCRIPT, Script, script) \
V(ALIASED_ARGUMENTS_ENTRY, AliasedArgumentsEntry, aliased_arguments_entry) \
V(PROMISE_RESOLVE_THENABLE_JOB_INFO, PromiseResolveThenableJobInfo, \
promise_resolve_thenable_job_info) \
V(PROMISE_REACTION_JOB_INFO, PromiseReactionJobInfo, \
promise_reaction_job_info) \
V(DEBUG_INFO, DebugInfo, debug_info) \
V(STACK_FRAME_INFO, StackFrameInfo, stack_frame_info) \
V(PROTOTYPE_INFO, PrototypeInfo, prototype_info) \
V(TUPLE2, Tuple2, tuple2) \
V(TUPLE3, Tuple3, tuple3) \
V(CONTEXT_EXTENSION, ContextExtension, context_extension) \
V(MODULE, Module, module) \
V(MODULE_INFO_ENTRY, ModuleInfoEntry, module_info_entry) \
V(ASYNC_GENERATOR_REQUEST, AsyncGeneratorRequest, async_generator_request)
// We use the full 8 bits of the instance_type field to encode heap object
// instance types. The high-order bit (bit 7) is set if the object is not a
// string, and cleared if it is a string.
const uint32_t kIsNotStringMask = 0x80;
const uint32_t kStringTag = 0x0;
const uint32_t kNotStringTag = 0x80;
// Bit 6 indicates that the object is an internalized string (if set) or not.
// Bit 7 has to be clear as well.
const uint32_t kIsNotInternalizedMask = 0x40;
const uint32_t kNotInternalizedTag = 0x40;
const uint32_t kInternalizedTag = 0x0;
// If bit 7 is clear then bit 3 indicates whether the string consists of
// two-byte characters or one-byte characters.
const uint32_t kStringEncodingMask = 0x8;
const uint32_t kTwoByteStringTag = 0x0;
const uint32_t kOneByteStringTag = 0x8;
// If bit 7 is clear, the low-order 3 bits indicate the representation
// of the string.
const uint32_t kStringRepresentationMask = 0x07;
enum StringRepresentationTag {
kSeqStringTag = 0x0,
kConsStringTag = 0x1,
kExternalStringTag = 0x2,
kSlicedStringTag = 0x3,
kThinStringTag = 0x5
};
const uint32_t kIsIndirectStringMask = 0x1;
const uint32_t kIsIndirectStringTag = 0x1;
STATIC_ASSERT((kSeqStringTag & kIsIndirectStringMask) == 0); // NOLINT
STATIC_ASSERT((kExternalStringTag & kIsIndirectStringMask) == 0); // NOLINT
STATIC_ASSERT((kConsStringTag &
kIsIndirectStringMask) == kIsIndirectStringTag); // NOLINT
STATIC_ASSERT((kSlicedStringTag &
kIsIndirectStringMask) == kIsIndirectStringTag); // NOLINT
STATIC_ASSERT((kThinStringTag & kIsIndirectStringMask) == kIsIndirectStringTag);
// If bit 7 is clear, then bit 4 indicates whether this two-byte
// string actually contains one byte data.
const uint32_t kOneByteDataHintMask = 0x10;
const uint32_t kOneByteDataHintTag = 0x10;
// If bit 7 is clear and string representation indicates an external string,
// then bit 5 indicates whether the data pointer is cached.
const uint32_t kShortExternalStringMask = 0x20;
const uint32_t kShortExternalStringTag = 0x20;
// A ConsString with an empty string as the right side is a candidate
// for being shortcut by the garbage collector. We don't allocate any
// non-flat internalized strings, so we do not shortcut them thereby
// avoiding turning internalized strings into strings. The bit-masks
// below contain the internalized bit as additional safety.
// See heap.cc, mark-compact.cc and objects-visiting.cc.
const uint32_t kShortcutTypeMask =
kIsNotStringMask |
kIsNotInternalizedMask |
kStringRepresentationMask;
const uint32_t kShortcutTypeTag = kConsStringTag | kNotInternalizedTag;
static inline bool IsShortcutCandidate(int type) {
return ((type & kShortcutTypeMask) == kShortcutTypeTag);
}
enum InstanceType {
// String types.
INTERNALIZED_STRING_TYPE = kTwoByteStringTag | kSeqStringTag |
kInternalizedTag, // FIRST_PRIMITIVE_TYPE
ONE_BYTE_INTERNALIZED_STRING_TYPE =
kOneByteStringTag | kSeqStringTag | kInternalizedTag,
EXTERNAL_INTERNALIZED_STRING_TYPE =
kTwoByteStringTag | kExternalStringTag | kInternalizedTag,
EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE =
kOneByteStringTag | kExternalStringTag | kInternalizedTag,
EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE =
EXTERNAL_INTERNALIZED_STRING_TYPE | kOneByteDataHintTag |
kInternalizedTag,
SHORT_EXTERNAL_INTERNALIZED_STRING_TYPE = EXTERNAL_INTERNALIZED_STRING_TYPE |
kShortExternalStringTag |
kInternalizedTag,
SHORT_EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE =
EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE | kShortExternalStringTag |
kInternalizedTag,
SHORT_EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE =
EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE |
kShortExternalStringTag | kInternalizedTag,
STRING_TYPE = INTERNALIZED_STRING_TYPE | kNotInternalizedTag,
ONE_BYTE_STRING_TYPE =
ONE_BYTE_INTERNALIZED_STRING_TYPE | kNotInternalizedTag,
CONS_STRING_TYPE = kTwoByteStringTag | kConsStringTag | kNotInternalizedTag,
CONS_ONE_BYTE_STRING_TYPE =
kOneByteStringTag | kConsStringTag | kNotInternalizedTag,
SLICED_STRING_TYPE =
kTwoByteStringTag | kSlicedStringTag | kNotInternalizedTag,
SLICED_ONE_BYTE_STRING_TYPE =
kOneByteStringTag | kSlicedStringTag | kNotInternalizedTag,
EXTERNAL_STRING_TYPE =
EXTERNAL_INTERNALIZED_STRING_TYPE | kNotInternalizedTag,
EXTERNAL_ONE_BYTE_STRING_TYPE =
EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE | kNotInternalizedTag,
EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE =
EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE |
kNotInternalizedTag,
SHORT_EXTERNAL_STRING_TYPE =
SHORT_EXTERNAL_INTERNALIZED_STRING_TYPE | kNotInternalizedTag,
SHORT_EXTERNAL_ONE_BYTE_STRING_TYPE =
SHORT_EXTERNAL_ONE_BYTE_INTERNALIZED_STRING_TYPE | kNotInternalizedTag,
SHORT_EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE =
SHORT_EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE |
kNotInternalizedTag,
THIN_STRING_TYPE = kTwoByteStringTag | kThinStringTag | kNotInternalizedTag,
THIN_ONE_BYTE_STRING_TYPE =
kOneByteStringTag | kThinStringTag | kNotInternalizedTag,
// Non-string names
SYMBOL_TYPE = kNotStringTag, // FIRST_NONSTRING_TYPE, LAST_NAME_TYPE
// Other primitives (cannot contain non-map-word pointers to heap objects).
HEAP_NUMBER_TYPE,
ODDBALL_TYPE, // LAST_PRIMITIVE_TYPE
// Objects allocated in their own spaces (never in new space).
MAP_TYPE,
CODE_TYPE,
// "Data", objects that cannot contain non-map-word pointers to heap
// objects.
MUTABLE_HEAP_NUMBER_TYPE,
FOREIGN_TYPE,
BYTE_ARRAY_TYPE,
BYTECODE_ARRAY_TYPE,
FREE_SPACE_TYPE,
FIXED_INT8_ARRAY_TYPE, // FIRST_FIXED_TYPED_ARRAY_TYPE
FIXED_UINT8_ARRAY_TYPE,
FIXED_INT16_ARRAY_TYPE,
FIXED_UINT16_ARRAY_TYPE,
FIXED_INT32_ARRAY_TYPE,
FIXED_UINT32_ARRAY_TYPE,
FIXED_FLOAT32_ARRAY_TYPE,
FIXED_FLOAT64_ARRAY_TYPE,
FIXED_UINT8_CLAMPED_ARRAY_TYPE, // LAST_FIXED_TYPED_ARRAY_TYPE
FIXED_DOUBLE_ARRAY_TYPE,
FILLER_TYPE, // LAST_DATA_TYPE
// Structs.
ACCESSOR_INFO_TYPE,
ACCESSOR_PAIR_TYPE,
ACCESS_CHECK_INFO_TYPE,
INTERCEPTOR_INFO_TYPE,
FUNCTION_TEMPLATE_INFO_TYPE,
OBJECT_TEMPLATE_INFO_TYPE,
ALLOCATION_SITE_TYPE,
ALLOCATION_MEMENTO_TYPE,
SCRIPT_TYPE,
ALIASED_ARGUMENTS_ENTRY_TYPE,
PROMISE_RESOLVE_THENABLE_JOB_INFO_TYPE,
PROMISE_REACTION_JOB_INFO_TYPE,
DEBUG_INFO_TYPE,
STACK_FRAME_INFO_TYPE,
PROTOTYPE_INFO_TYPE,
TUPLE2_TYPE,
TUPLE3_TYPE,
CONTEXT_EXTENSION_TYPE,
MODULE_TYPE,
MODULE_INFO_ENTRY_TYPE,
ASYNC_GENERATOR_REQUEST_TYPE,
FIXED_ARRAY_TYPE,
TRANSITION_ARRAY_TYPE,
SHARED_FUNCTION_INFO_TYPE,
CELL_TYPE,
WEAK_CELL_TYPE,
PROPERTY_CELL_TYPE,
// TODO(yangguo): these padding types are for ABI stability. Remove after
// version 6.0 branch, or replace them when there is demand for new types.
PADDING_TYPE_1,
PADDING_TYPE_2,
PADDING_TYPE_3,
PADDING_TYPE_4,
// All the following types are subtypes of JSReceiver, which corresponds to
// objects in the JS sense. The first and the last type in this range are
// the two forms of function. This organization enables using the same
// compares for checking the JS_RECEIVER and the NONCALLABLE_JS_OBJECT range.
JS_PROXY_TYPE, // FIRST_JS_RECEIVER_TYPE
JS_GLOBAL_OBJECT_TYPE, // FIRST_JS_OBJECT_TYPE
JS_GLOBAL_PROXY_TYPE,
// Like JS_API_OBJECT_TYPE, but requires access checks and/or has
// interceptors.
JS_SPECIAL_API_OBJECT_TYPE, // LAST_SPECIAL_RECEIVER_TYPE
JS_VALUE_TYPE, // LAST_CUSTOM_ELEMENTS_RECEIVER
JS_MESSAGE_OBJECT_TYPE,
JS_DATE_TYPE,
// Like JS_OBJECT_TYPE, but created from API function.
JS_API_OBJECT_TYPE,
JS_OBJECT_TYPE,
JS_ARGUMENTS_TYPE,
JS_CONTEXT_EXTENSION_OBJECT_TYPE,
JS_GENERATOR_OBJECT_TYPE,
JS_ASYNC_GENERATOR_OBJECT_TYPE,
JS_MODULE_NAMESPACE_TYPE,
JS_ARRAY_TYPE,
JS_ARRAY_BUFFER_TYPE,
JS_TYPED_ARRAY_TYPE,
JS_DATA_VIEW_TYPE,
JS_SET_TYPE,
JS_MAP_TYPE,
JS_SET_ITERATOR_TYPE,
JS_MAP_ITERATOR_TYPE,
JS_WEAK_MAP_TYPE,
JS_WEAK_SET_TYPE,
JS_PROMISE_CAPABILITY_TYPE,
JS_PROMISE_TYPE,
JS_REGEXP_TYPE,
JS_ERROR_TYPE,
JS_ASYNC_FROM_SYNC_ITERATOR_TYPE,
JS_STRING_ITERATOR_TYPE,
JS_TYPED_ARRAY_KEY_ITERATOR_TYPE,
JS_FAST_ARRAY_KEY_ITERATOR_TYPE,
JS_GENERIC_ARRAY_KEY_ITERATOR_TYPE,
JS_UINT8_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_INT8_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_UINT16_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_INT16_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_UINT32_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_INT32_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FLOAT32_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FLOAT64_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_UINT8_CLAMPED_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FAST_SMI_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FAST_HOLEY_SMI_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FAST_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FAST_HOLEY_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FAST_DOUBLE_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_FAST_HOLEY_DOUBLE_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_GENERIC_ARRAY_KEY_VALUE_ITERATOR_TYPE,
JS_UINT8_ARRAY_VALUE_ITERATOR_TYPE,
JS_INT8_ARRAY_VALUE_ITERATOR_TYPE,
JS_UINT16_ARRAY_VALUE_ITERATOR_TYPE,
JS_INT16_ARRAY_VALUE_ITERATOR_TYPE,
JS_UINT32_ARRAY_VALUE_ITERATOR_TYPE,
JS_INT32_ARRAY_VALUE_ITERATOR_TYPE,
JS_FLOAT32_ARRAY_VALUE_ITERATOR_TYPE,
JS_FLOAT64_ARRAY_VALUE_ITERATOR_TYPE,
JS_UINT8_CLAMPED_ARRAY_VALUE_ITERATOR_TYPE,
JS_FAST_SMI_ARRAY_VALUE_ITERATOR_TYPE,
JS_FAST_HOLEY_SMI_ARRAY_VALUE_ITERATOR_TYPE,
JS_FAST_ARRAY_VALUE_ITERATOR_TYPE,
JS_FAST_HOLEY_ARRAY_VALUE_ITERATOR_TYPE,
JS_FAST_DOUBLE_ARRAY_VALUE_ITERATOR_TYPE,
JS_FAST_HOLEY_DOUBLE_ARRAY_VALUE_ITERATOR_TYPE,
JS_GENERIC_ARRAY_VALUE_ITERATOR_TYPE,
JS_BOUND_FUNCTION_TYPE,
JS_FUNCTION_TYPE, // LAST_JS_OBJECT_TYPE, LAST_JS_RECEIVER_TYPE
// Pseudo-types
FIRST_TYPE = 0x0,
LAST_TYPE = JS_FUNCTION_TYPE,
FIRST_NAME_TYPE = FIRST_TYPE,
LAST_NAME_TYPE = SYMBOL_TYPE,
FIRST_UNIQUE_NAME_TYPE = INTERNALIZED_STRING_TYPE,
LAST_UNIQUE_NAME_TYPE = SYMBOL_TYPE,
FIRST_NONSTRING_TYPE = SYMBOL_TYPE,
FIRST_PRIMITIVE_TYPE = FIRST_NAME_TYPE,
LAST_PRIMITIVE_TYPE = ODDBALL_TYPE,
FIRST_FUNCTION_TYPE = JS_BOUND_FUNCTION_TYPE,
LAST_FUNCTION_TYPE = JS_FUNCTION_TYPE,
// Boundaries for testing for a fixed typed array.
FIRST_FIXED_TYPED_ARRAY_TYPE = FIXED_INT8_ARRAY_TYPE,
LAST_FIXED_TYPED_ARRAY_TYPE = FIXED_UINT8_CLAMPED_ARRAY_TYPE,
// Boundary for promotion to old space.
LAST_DATA_TYPE = FILLER_TYPE,
// Boundary for objects represented as JSReceiver (i.e. JSObject or JSProxy).
// Note that there is no range for JSObject or JSProxy, since their subtypes
// are not continuous in this enum! The enum ranges instead reflect the
// external class names, where proxies are treated as either ordinary objects,
// or functions.
FIRST_JS_RECEIVER_TYPE = JS_PROXY_TYPE,
LAST_JS_RECEIVER_TYPE = LAST_TYPE,
// Boundaries for testing the types represented as JSObject
FIRST_JS_OBJECT_TYPE = JS_GLOBAL_OBJECT_TYPE,
LAST_JS_OBJECT_TYPE = LAST_TYPE,
// Boundary for testing JSReceivers that need special property lookup handling
LAST_SPECIAL_RECEIVER_TYPE = JS_SPECIAL_API_OBJECT_TYPE,
// Boundary case for testing JSReceivers that may have elements while having
// an empty fixed array as elements backing store. This is true for string
// wrappers.
LAST_CUSTOM_ELEMENTS_RECEIVER = JS_VALUE_TYPE,
FIRST_ARRAY_KEY_ITERATOR_TYPE = JS_TYPED_ARRAY_KEY_ITERATOR_TYPE,
LAST_ARRAY_KEY_ITERATOR_TYPE = JS_GENERIC_ARRAY_KEY_ITERATOR_TYPE,
FIRST_ARRAY_KEY_VALUE_ITERATOR_TYPE = JS_UINT8_ARRAY_KEY_VALUE_ITERATOR_TYPE,
LAST_ARRAY_KEY_VALUE_ITERATOR_TYPE = JS_GENERIC_ARRAY_KEY_VALUE_ITERATOR_TYPE,
FIRST_ARRAY_VALUE_ITERATOR_TYPE = JS_UINT8_ARRAY_VALUE_ITERATOR_TYPE,
LAST_ARRAY_VALUE_ITERATOR_TYPE = JS_GENERIC_ARRAY_VALUE_ITERATOR_TYPE,
FIRST_ARRAY_ITERATOR_TYPE = FIRST_ARRAY_KEY_ITERATOR_TYPE,
LAST_ARRAY_ITERATOR_TYPE = LAST_ARRAY_VALUE_ITERATOR_TYPE,
};
STATIC_ASSERT(JS_OBJECT_TYPE == Internals::kJSObjectType);
STATIC_ASSERT(JS_API_OBJECT_TYPE == Internals::kJSApiObjectType);
STATIC_ASSERT(FIRST_NONSTRING_TYPE == Internals::kFirstNonstringType);
STATIC_ASSERT(ODDBALL_TYPE == Internals::kOddballType);
STATIC_ASSERT(FOREIGN_TYPE == Internals::kForeignType);
V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os,
InstanceType instance_type);
#define FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(V) \
V(BYTECODE_ARRAY_CONSTANT_POOL_SUB_TYPE) \
V(BYTECODE_ARRAY_HANDLER_TABLE_SUB_TYPE) \
V(CODE_STUBS_TABLE_SUB_TYPE) \
V(COMPILATION_CACHE_TABLE_SUB_TYPE) \
V(CONTEXT_SUB_TYPE) \
V(COPY_ON_WRITE_SUB_TYPE) \
V(DEOPTIMIZATION_DATA_SUB_TYPE) \
V(DESCRIPTOR_ARRAY_SUB_TYPE) \
V(EMBEDDED_OBJECT_SUB_TYPE) \
V(ENUM_CACHE_SUB_TYPE) \
V(ENUM_INDICES_CACHE_SUB_TYPE) \
V(DEPENDENT_CODE_SUB_TYPE) \
V(DICTIONARY_ELEMENTS_SUB_TYPE) \
V(DICTIONARY_PROPERTIES_SUB_TYPE) \
V(EMPTY_PROPERTIES_DICTIONARY_SUB_TYPE) \
V(FAST_ELEMENTS_SUB_TYPE) \
V(FAST_PROPERTIES_SUB_TYPE) \
V(FAST_TEMPLATE_INSTANTIATIONS_CACHE_SUB_TYPE) \
V(HANDLER_TABLE_SUB_TYPE) \
V(JS_COLLECTION_SUB_TYPE) \
V(JS_WEAK_COLLECTION_SUB_TYPE) \
V(MAP_CODE_CACHE_SUB_TYPE) \
V(NOSCRIPT_SHARED_FUNCTION_INFOS_SUB_TYPE) \
V(NUMBER_STRING_CACHE_SUB_TYPE) \
V(OBJECT_TO_CODE_SUB_TYPE) \
V(OPTIMIZED_CODE_LITERALS_SUB_TYPE) \
V(OPTIMIZED_CODE_MAP_SUB_TYPE) \
V(PROTOTYPE_USERS_SUB_TYPE) \
V(REGEXP_MULTIPLE_CACHE_SUB_TYPE) \
V(RETAINED_MAPS_SUB_TYPE) \
V(SCOPE_INFO_SUB_TYPE) \
V(SCRIPT_LIST_SUB_TYPE) \
V(SERIALIZED_TEMPLATES_SUB_TYPE) \
V(SHARED_FUNCTION_INFOS_SUB_TYPE) \
V(SINGLE_CHARACTER_STRING_CACHE_SUB_TYPE) \
V(SLOW_TEMPLATE_INSTANTIATIONS_CACHE_SUB_TYPE) \
V(STRING_SPLIT_CACHE_SUB_TYPE) \
V(STRING_TABLE_SUB_TYPE) \
V(TEMPLATE_INFO_SUB_TYPE) \
V(FEEDBACK_VECTOR_SUB_TYPE) \
V(FEEDBACK_METADATA_SUB_TYPE) \
V(WEAK_NEW_SPACE_OBJECT_TO_CODE_SUB_TYPE)
enum FixedArraySubInstanceType {
#define DEFINE_FIXED_ARRAY_SUB_INSTANCE_TYPE(name) name,
FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(DEFINE_FIXED_ARRAY_SUB_INSTANCE_TYPE)
#undef DEFINE_FIXED_ARRAY_SUB_INSTANCE_TYPE
LAST_FIXED_ARRAY_SUB_TYPE = WEAK_NEW_SPACE_OBJECT_TO_CODE_SUB_TYPE
};
// TODO(bmeurer): Remove this in favor of the ComparisonResult below.
enum CompareResult {
LESS = -1,
EQUAL = 0,
GREATER = 1,
NOT_EQUAL = GREATER
};
// Result of an abstract relational comparison of x and y, implemented according
// to ES6 section 7.2.11 Abstract Relational Comparison.
enum class ComparisonResult {
kLessThan, // x < y
kEqual, // x = y
kGreaterThan, // x > y
kUndefined // at least one of x or y was undefined or NaN
};
class AbstractCode;
class AccessorPair;
class AllocationSite;
class AllocationSiteCreationContext;
class AllocationSiteUsageContext;
class Cell;
class ConsString;
class ElementsAccessor;
class FindAndReplacePattern;
class FixedArrayBase;
class FunctionLiteral;
class JSGlobalObject;
class KeyAccumulator;
class LayoutDescriptor;
class LookupIterator;
class FieldType;
class Module;
class ModuleDescriptor;
class ModuleInfoEntry;
class ModuleInfo;
class ObjectHashTable;
class ObjectVisitor;
class PropertyCell;
class PropertyDescriptor;
class RootVisitor;
class SafepointEntry;
class SharedFunctionInfo;
class StringStream;
class TypeFeedbackInfo;
class FeedbackMetadata;
class FeedbackVector;
class WeakCell;
class TransitionArray;
class TemplateList;
// A template-ized version of the IsXXX functions.
template <class C> inline bool Is(Object* obj);
#ifdef OBJECT_PRINT
#define DECLARE_PRINTER(Name) void Name##Print(std::ostream& os); // NOLINT
#else
#define DECLARE_PRINTER(Name)
#endif
#define OBJECT_TYPE_LIST(V) \
V(Smi) \
V(LayoutDescriptor) \
V(HeapObject) \
V(Primitive) \
V(Number)
#define HEAP_OBJECT_TYPE_LIST(V) \
V(AbstractCode) \
V(AccessCheckNeeded) \
V(ArrayList) \
V(BoilerplateDescription) \
V(Boolean) \
V(BreakPointInfo) \
V(ByteArray) \
V(BytecodeArray) \
V(Callable) \
V(CallHandlerInfo) \
V(Cell) \
V(Code) \
V(CodeCacheHashTable) \
V(CompilationCacheTable) \
V(ConsString) \
V(ConstantElementsPair) \
V(Constructor) \
V(Context) \
V(DeoptimizationInputData) \
V(DeoptimizationOutputData) \
V(DependentCode) \
V(DescriptorArray) \
V(Dictionary) \
V(External) \
V(ExternalOneByteString) \
V(ExternalString) \
V(ExternalTwoByteString) \
V(FeedbackMetadata) \
V(FeedbackVector) \
V(Filler) \
V(FixedArray) \
V(FixedArrayBase) \
V(FixedDoubleArray) \
V(FixedFloat32Array) \
V(FixedFloat64Array) \
V(FixedInt16Array) \
V(FixedInt32Array) \
V(FixedInt8Array) \
V(FixedTypedArrayBase) \
V(FixedUint16Array) \
V(FixedUint32Array) \
V(FixedUint8Array) \
V(FixedUint8ClampedArray) \
V(Foreign) \
V(FrameArray) \
V(FreeSpace) \
V(Function) \
V(HandlerTable) \
V(HashTable) \
V(HeapNumber) \
V(InternalizedString) \
V(JSArgumentsObject) \
V(JSArray) \
V(JSArrayBuffer) \
V(JSArrayBufferView) \
V(JSArrayIterator) \
V(JSAsyncFromSyncIterator) \
V(JSAsyncGeneratorObject) \
V(JSBoundFunction) \
V(JSCollection) \
V(JSContextExtensionObject) \
V(JSDataView) \
V(JSDate) \
V(JSError) \
V(JSFunction) \
V(JSGeneratorObject) \
V(JSGlobalObject) \
V(JSGlobalProxy) \
V(JSMap) \
V(JSMapIterator) \
V(JSMessageObject) \
V(JSModuleNamespace) \
V(JSObject) \
V(JSPromise) \
V(JSPromiseCapability) \
V(JSProxy) \
V(JSReceiver) \
V(JSRegExp) \
V(JSSet) \
V(JSSetIterator) \
V(JSSloppyArgumentsObject) \
V(JSStringIterator) \
V(JSTypedArray) \
V(JSValue) \
V(JSWeakCollection) \
V(JSWeakMap) \
V(JSWeakSet) \
V(Map) \
V(MapCache) \
V(ModuleInfo) \
V(MutableHeapNumber) \
V(Name) \
V(NativeContext) \
V(NormalizedMapCache) \
V(ObjectHashSet) \
V(ObjectHashTable) \
V(Oddball) \
V(OrderedHashTable) \
V(PropertyCell) \
V(RegExpMatchInfo) \
V(ScopeInfo) \
V(ScriptContextTable) \
V(SeqOneByteString) \
V(SeqString) \
V(SeqTwoByteString) \
V(SharedFunctionInfo) \
V(SlicedString) \
V(SloppyArgumentsElements) \
V(SourcePositionTableWithFrameCache) \
V(String) \
V(StringSet) \
V(StringTable) \
V(StringWrapper) \
V(Struct) \
V(Symbol) \
V(TemplateInfo) \
V(TemplateList) \
V(ThinString) \
V(TransitionArray) \
V(TypeFeedbackInfo) \
V(Undetectable) \
V(UniqueName) \
V(UnseededNumberDictionary) \
V(WeakCell) \
V(WeakFixedArray) \
V(WeakHashTable)
#define ODDBALL_LIST(V) \
V(Undefined, undefined_value) \
V(Null, null_value) \
V(TheHole, the_hole_value) \
V(Exception, exception) \
V(Uninitialized, uninitialized_value) \
V(True, true_value) \
V(False, false_value) \
V(ArgumentsMarker, arguments_marker) \
V(OptimizedOut, optimized_out) \
V(StaleRegister, stale_register)
// The element types selection for CreateListFromArrayLike.
enum class ElementTypes { kAll, kStringAndSymbol };
// Object is the abstract superclass for all classes in the
// object hierarchy.
// Object does not use any virtual functions to avoid the
// allocation of the C++ vtable.
// Since both Smi and HeapObject are subclasses of Object no
// data members can be present in Object.
class Object {
public:
// Type testing.
bool IsObject() const { return true; }
#define IS_TYPE_FUNCTION_DECL(Type) INLINE(bool Is##Type() const);
OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
HEAP_OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
#undef IS_TYPE_FUNCTION_DECL
#define IS_TYPE_FUNCTION_DECL(Type, Value) \
INLINE(bool Is##Type(Isolate* isolate) const);
ODDBALL_LIST(IS_TYPE_FUNCTION_DECL)
#undef IS_TYPE_FUNCTION_DECL
INLINE(bool IsNullOrUndefined(Isolate* isolate) const);
// A non-keyed store is of the form a.x = foo or a["x"] = foo whereas
// a keyed store is of the form a[expression] = foo.
enum StoreFromKeyed {
MAY_BE_STORE_FROM_KEYED,
CERTAINLY_NOT_STORE_FROM_KEYED
};
enum ShouldThrow { THROW_ON_ERROR, DONT_THROW };
#define RETURN_FAILURE(isolate, should_throw, call) \
do { \
if ((should_throw) == DONT_THROW) { \
return Just(false); \
} else { \
isolate->Throw(*isolate->factory()->call); \
return Nothing<bool>(); \
} \
} while (false)
#define MAYBE_RETURN(call, value) \
do { \
if ((call).IsNothing()) return value; \
} while (false)
#define MAYBE_RETURN_NULL(call) MAYBE_RETURN(call, MaybeHandle<Object>())
#define DECLARE_STRUCT_PREDICATE(NAME, Name, name) \
INLINE(bool Is##Name() const);
STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
#undef DECLARE_STRUCT_PREDICATE
// ES6, section 7.2.2 IsArray. NOT to be confused with %_IsArray.
MUST_USE_RESULT static Maybe<bool> IsArray(Handle<Object> object);
INLINE(bool IsNameDictionary() const);
INLINE(bool IsGlobalDictionary() const);
INLINE(bool IsSeededNumberDictionary() const);
INLINE(bool IsOrderedHashSet() const);
INLINE(bool IsOrderedHashMap() const);
// Extract the number.
inline double Number() const;
INLINE(bool IsNaN() const);
INLINE(bool IsMinusZero() const);
V8_EXPORT_PRIVATE bool ToInt32(int32_t* value);
inline bool ToUint32(uint32_t* value);
inline Representation OptimalRepresentation();
inline ElementsKind OptimalElementsKind();
inline bool FitsRepresentation(Representation representation);
// Checks whether two valid primitive encodings of a property name resolve to
// the same logical property. E.g., the smi 1, the string "1" and the double
// 1 all refer to the same property, so this helper will return true.
inline bool KeyEquals(Object* other);
inline bool FilterKey(PropertyFilter filter);
Handle<FieldType> OptimalType(Isolate* isolate,
Representation representation);
inline static Handle<Object> NewStorageFor(Isolate* isolate,
Handle<Object> object,
Representation representation);
inline static Handle<Object> WrapForRead(Isolate* isolate,
Handle<Object> object,
Representation representation);
// Returns true if the object is of the correct type to be used as a
// implementation of a JSObject's elements.
inline bool HasValidElements();
inline bool HasSpecificClassOf(String* name);
bool BooleanValue(); // ECMA-262 9.2.
// ES6 section 7.2.11 Abstract Relational Comparison
MUST_USE_RESULT static Maybe<ComparisonResult> Compare(Handle<Object> x,
Handle<Object> y);
// ES6 section 7.2.12 Abstract Equality Comparison
MUST_USE_RESULT static Maybe<bool> Equals(Handle<Object> x, Handle<Object> y);
// ES6 section 7.2.13 Strict Equality Comparison
bool StrictEquals(Object* that);
// ES6 section 7.1.13 ToObject
// Convert to a JSObject if needed.
// native_context is used when creating wrapper object.
//
// Passing a non-null method_name allows us to give a more informative
// error message for those cases where ToObject is being called on
// the receiver of a built-in method.
MUST_USE_RESULT static inline MaybeHandle<JSReceiver> ToObject(
Isolate* isolate, Handle<Object> object,
const char* method_name = nullptr);
MUST_USE_RESULT static MaybeHandle<JSReceiver> ToObject(
Isolate* isolate, Handle<Object> object, Handle<Context> native_context,
const char* method_name = nullptr);
// ES6 section 9.2.1.2, OrdinaryCallBindThis for sloppy callee.
MUST_USE_RESULT static MaybeHandle<JSReceiver> ConvertReceiver(
Isolate* isolate, Handle<Object> object);
// ES6 section 7.1.14 ToPropertyKey
MUST_USE_RESULT static inline MaybeHandle<Name> ToName(Isolate* isolate,
Handle<Object> input);
// ES6 section 7.1.1 ToPrimitive
MUST_USE_RESULT static inline MaybeHandle<Object> ToPrimitive(
Handle<Object> input, ToPrimitiveHint hint = ToPrimitiveHint::kDefault);
// ES6 section 7.1.3 ToNumber
MUST_USE_RESULT static inline MaybeHandle<Object> ToNumber(
Handle<Object> input);
// ES6 section 7.1.4 ToInteger
MUST_USE_RESULT static inline MaybeHandle<Object> ToInteger(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.5 ToInt32
MUST_USE_RESULT static inline MaybeHandle<Object> ToInt32(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.6 ToUint32
MUST_USE_RESULT inline static MaybeHandle<Object> ToUint32(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.12 ToString
MUST_USE_RESULT static inline MaybeHandle<String> ToString(
Isolate* isolate, Handle<Object> input);
static Handle<String> NoSideEffectsToString(Isolate* isolate,
Handle<Object> input);
// ES6 section 7.1.14 ToPropertyKey
MUST_USE_RESULT static inline MaybeHandle<Object> ToPropertyKey(
Isolate* isolate, Handle<Object> value);
// ES6 section 7.1.15 ToLength
MUST_USE_RESULT static inline MaybeHandle<Object> ToLength(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.17 ToIndex
MUST_USE_RESULT static inline MaybeHandle<Object> ToIndex(
Isolate* isolate, Handle<Object> input,
MessageTemplate::Template error_index);
// ES6 section 7.3.9 GetMethod
MUST_USE_RESULT static MaybeHandle<Object> GetMethod(
Handle<JSReceiver> receiver, Handle<Name> name);
// ES6 section 7.3.17 CreateListFromArrayLike
MUST_USE_RESULT static MaybeHandle<FixedArray> CreateListFromArrayLike(
Isolate* isolate, Handle<Object> object, ElementTypes element_types);
// Get length property and apply ToLength.
MUST_USE_RESULT static MaybeHandle<Object> GetLengthFromArrayLike(
Isolate* isolate, Handle<Object> object);
// ES6 section 12.5.6 The typeof Operator
static Handle<String> TypeOf(Isolate* isolate, Handle<Object> object);
// ES6 section 12.6 Multiplicative Operators
MUST_USE_RESULT static MaybeHandle<Object> Multiply(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> Divide(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> Modulus(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
// ES6 section 12.7 Additive Operators
MUST_USE_RESULT static MaybeHandle<Object> Add(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> Subtract(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
// ES6 section 12.8 Bitwise Shift Operators
MUST_USE_RESULT static MaybeHandle<Object> ShiftLeft(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> ShiftRight(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> ShiftRightLogical(
Isolate* isolate, Handle<Object> lhs, Handle<Object> rhs);
// ES6 section 12.9 Relational Operators
MUST_USE_RESULT static inline Maybe<bool> GreaterThan(Handle<Object> x,
Handle<Object> y);
MUST_USE_RESULT static inline Maybe<bool> GreaterThanOrEqual(
Handle<Object> x, Handle<Object> y);
MUST_USE_RESULT static inline Maybe<bool> LessThan(Handle<Object> x,
Handle<Object> y);
MUST_USE_RESULT static inline Maybe<bool> LessThanOrEqual(Handle<Object> x,
Handle<Object> y);
// ES6 section 12.11 Binary Bitwise Operators
MUST_USE_RESULT static MaybeHandle<Object> BitwiseAnd(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> BitwiseOr(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
MUST_USE_RESULT static MaybeHandle<Object> BitwiseXor(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
// ES6 section 7.3.19 OrdinaryHasInstance (C, O).
MUST_USE_RESULT static MaybeHandle<Object> OrdinaryHasInstance(
Isolate* isolate, Handle<Object> callable, Handle<Object> object);
// ES6 section 12.10.4 Runtime Semantics: InstanceofOperator(O, C)
MUST_USE_RESULT static MaybeHandle<Object> InstanceOf(
Isolate* isolate, Handle<Object> object, Handle<Object> callable);
V8_EXPORT_PRIVATE MUST_USE_RESULT static MaybeHandle<Object> GetProperty(
LookupIterator* it);
// ES6 [[Set]] (when passed DONT_THROW)
// Invariants for this and related functions (unless stated otherwise):
// 1) When the result is Nothing, an exception is pending.
// 2) When passed THROW_ON_ERROR, the result is never Just(false).
// In some cases, an exception is thrown regardless of the ShouldThrow
// argument. These cases are either in accordance with the spec or not
// covered by it (eg., concerning API callbacks).
MUST_USE_RESULT static Maybe<bool> SetProperty(LookupIterator* it,
Handle<Object> value,
LanguageMode language_mode,
StoreFromKeyed store_mode);
MUST_USE_RESULT static MaybeHandle<Object> SetProperty(
Handle<Object> object, Handle<Name> name, Handle<Object> value,
LanguageMode language_mode,
StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED);
MUST_USE_RESULT static inline MaybeHandle<Object> SetPropertyOrElement(
Handle<Object> object, Handle<Name> name, Handle<Object> value,
LanguageMode language_mode,
StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED);
MUST_USE_RESULT static Maybe<bool> SetSuperProperty(
LookupIterator* it, Handle<Object> value, LanguageMode language_mode,
StoreFromKeyed store_mode);
MUST_USE_RESULT static Maybe<bool> CannotCreateProperty(
Isolate* isolate, Handle<Object> receiver, Handle<Object> name,
Handle<Object> value, ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> WriteToReadOnlyProperty(
LookupIterator* it, Handle<Object> value, ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> WriteToReadOnlyProperty(
Isolate* isolate, Handle<Object> receiver, Handle<Object> name,
Handle<Object> value, ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> RedefineIncompatibleProperty(
Isolate* isolate, Handle<Object> name, Handle<Object> value,
ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> SetDataProperty(LookupIterator* it,
Handle<Object> value);
MUST_USE_RESULT static Maybe<bool> AddDataProperty(
LookupIterator* it, Handle<Object> value, PropertyAttributes attributes,
ShouldThrow should_throw, StoreFromKeyed store_mode);
MUST_USE_RESULT static inline MaybeHandle<Object> GetPropertyOrElement(
Handle<Object> object, Handle<Name> name);
MUST_USE_RESULT static inline MaybeHandle<Object> GetPropertyOrElement(
Handle<Object> receiver, Handle<Name> name, Handle<JSReceiver> holder);
MUST_USE_RESULT static inline MaybeHandle<Object> GetProperty(
Handle<Object> object, Handle<Name> name);
MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithAccessor(
LookupIterator* it);
MUST_USE_RESULT static Maybe<bool> SetPropertyWithAccessor(
LookupIterator* it, Handle<Object> value, ShouldThrow should_throw);
MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithDefinedGetter(
Handle<Object> receiver,
Handle<JSReceiver> getter);
MUST_USE_RESULT static Maybe<bool> SetPropertyWithDefinedSetter(
Handle<Object> receiver, Handle<JSReceiver> setter, Handle<Object> value,
ShouldThrow should_throw);
MUST_USE_RESULT static inline MaybeHandle<Object> GetElement(
Isolate* isolate, Handle<Object> object, uint32_t index);
MUST_USE_RESULT static inline MaybeHandle<Object> SetElement(
Isolate* isolate, Handle<Object> object, uint32_t index,
Handle<Object> value, LanguageMode language_mode);
// Returns the permanent hash code associated with this object. May return
// undefined if not yet created.
Object* GetHash();
// Returns the permanent hash code associated with this object depending on
// the actual object type. May create and store a hash code if needed and none
// exists.
static Smi* GetOrCreateHash(Isolate* isolate, Handle<Object> object);
// Checks whether this object has the same value as the given one. This
// function is implemented according to ES5, section 9.12 and can be used
// to implement the Harmony "egal" function.
V8_EXPORT_PRIVATE bool SameValue(Object* other);
// Checks whether this object has the same value as the given one.
// +0 and -0 are treated equal. Everything else is the same as SameValue.
// This function is implemented according to ES6, section 7.2.4 and is used
// by ES6 Map and Set.
bool SameValueZero(Object* other);
// ES6 section 9.4.2.3 ArraySpeciesCreate (part of it)
MUST_USE_RESULT static MaybeHandle<Object> ArraySpeciesConstructor(
Isolate* isolate, Handle<Object> original_array);
// ES6 section 7.3.20 SpeciesConstructor ( O, defaultConstructor )
MUST_USE_RESULT static MaybeHandle<Object> SpeciesConstructor(
Isolate* isolate, Handle<JSReceiver> recv,
Handle<JSFunction> default_ctor);
// Tries to convert an object to an array length. Returns true and sets the
// output parameter if it succeeds.
inline bool ToArrayLength(uint32_t* index);
// Tries to convert an object to an array index. Returns true and sets the
// output parameter if it succeeds. Equivalent to ToArrayLength, but does not
// allow kMaxUInt32.
inline bool ToArrayIndex(uint32_t* index);
// Returns true if the result of iterating over the object is the same
// (including observable effects) as simply accessing the properties between 0
// and length.
bool IterationHasObservableEffects();
DECLARE_VERIFIER(Object)
#ifdef VERIFY_HEAP
// Verify a pointer is a valid object pointer.
static void VerifyPointer(Object* p);
#endif
inline void VerifyApiCallResultType();
// Prints this object without details.
void ShortPrint(FILE* out = stdout);
// Prints this object without details to a message accumulator.
void ShortPrint(StringStream* accumulator);
void ShortPrint(std::ostream& os); // NOLINT
DECLARE_CAST(Object)
// Layout description.
static const int kHeaderSize = 0; // Object does not take up any space.
#ifdef OBJECT_PRINT
// For our gdb macros, we should perhaps change these in the future.
void Print();
// Prints this object with details.
void Print(std::ostream& os); // NOLINT
#else
void Print() { ShortPrint(); }
void Print(std::ostream& os) { ShortPrint(os); } // NOLINT
#endif
private:
friend class LookupIterator;
friend class StringStream;
// Return the map of the root of object's prototype chain.
Map* GetPrototypeChainRootMap(Isolate* isolate);
// Helper for SetProperty and SetSuperProperty.
// Return value is only meaningful if [found] is set to true on return.
MUST_USE_RESULT static Maybe<bool> SetPropertyInternal(
LookupIterator* it, Handle<Object> value, LanguageMode language_mode,
StoreFromKeyed store_mode, bool* found);
MUST_USE_RESULT static MaybeHandle<Name> ConvertToName(Isolate* isolate,
Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToPropertyKey(
Isolate* isolate, Handle<Object> value);
MUST_USE_RESULT static MaybeHandle<String> ConvertToString(
Isolate* isolate, Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToNumber(
Isolate* isolate, Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToInteger(
Isolate* isolate, Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToInt32(
Isolate* isolate, Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToUint32(
Isolate* isolate, Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToLength(
Isolate* isolate, Handle<Object> input);
MUST_USE_RESULT static MaybeHandle<Object> ConvertToIndex(
Isolate* isolate, Handle<Object> input,
MessageTemplate::Template error_index);
DISALLOW_IMPLICIT_CONSTRUCTORS(Object);
};
// In objects.h to be usable without objects-inl.h inclusion.
bool Object::IsSmi() const { return HAS_SMI_TAG(this); }
bool Object::IsHeapObject() const {
DCHECK_EQ(!IsSmi(), Internals::HasHeapObjectTag(this));
return !IsSmi();
}
struct Brief {
explicit Brief(const Object* const v) : value(v) {}
const Object* value;
};
V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os, const Brief& v);
// Smi represents integer Numbers that can be stored in 31 bits.
// Smis are immediate which means they are NOT allocated in the heap.
// The this pointer has the following format: [31 bit signed int] 0
// For long smis it has the following format:
// [32 bit signed int] [31 bits zero padding] 0
// Smi stands for small integer.
class Smi: public Object {
public:
// Returns the integer value.
inline int value() const { return Internals::SmiValue(this); }
inline Smi* ToUint32Smi() {
if (value() <= 0) return Smi::kZero;
return Smi::FromInt(static_cast<uint32_t>(value()));
}
// Convert a value to a Smi object.
static inline Smi* FromInt(int value) {
DCHECK(Smi::IsValid(value));
return reinterpret_cast<Smi*>(Internals::IntToSmi(value));
}
static inline Smi* FromIntptr(intptr_t value) {
DCHECK(Smi::IsValid(value));
int smi_shift_bits = kSmiTagSize + kSmiShiftSize;
return reinterpret_cast<Smi*>((value << smi_shift_bits) | kSmiTag);
}
// Returns whether value can be represented in a Smi.
static inline bool IsValid(intptr_t value) {
bool result = Internals::IsValidSmi(value);
DCHECK_EQ(result, value >= kMinValue && value <= kMaxValue);
return result;
}
DECLARE_CAST(Smi)
// Dispatched behavior.
V8_EXPORT_PRIVATE void SmiPrint(std::ostream& os) const; // NOLINT
DECLARE_VERIFIER(Smi)
static constexpr Smi* const kZero = nullptr;
static const int kMinValue =
(static_cast<unsigned int>(-1)) << (kSmiValueSize - 1);
static const int kMaxValue = -(kMinValue + 1);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Smi);
};
// Heap objects typically have a map pointer in their first word. However,
// during GC other data (e.g. mark bits, forwarding addresses) is sometimes
// encoded in the first word. The class MapWord is an abstraction of the
// value in a heap object's first word.
class MapWord BASE_EMBEDDED {
public:
// Normal state: the map word contains a map pointer.
// Create a map word from a map pointer.
static inline MapWord FromMap(const Map* map);
// View this map word as a map pointer.
inline Map* ToMap();
// Scavenge collection: the map word of live objects in the from space
// contains a forwarding address (a heap object pointer in the to space).
// True if this map word is a forwarding address for a scavenge
// collection. Only valid during a scavenge collection (specifically,
// when all map words are heap object pointers, i.e. not during a full GC).
inline bool IsForwardingAddress() const;
// Create a map word from a forwarding address.
static inline MapWord FromForwardingAddress(HeapObject* object);
// View this map word as a forwarding address.
inline HeapObject* ToForwardingAddress();
static inline MapWord FromRawValue(uintptr_t value) {
return MapWord(value);
}
inline uintptr_t ToRawValue() {
return value_;
}
private:
// HeapObject calls the private constructor and directly reads the value.
friend class HeapObject;
explicit MapWord(uintptr_t value) : value_(value) {}
uintptr_t value_;
};
// HeapObject is the superclass for all classes describing heap allocated
// objects.
class HeapObject: public Object {
public:
// [map]: Contains a map which contains the object's reflective
// information.
inline Map* map() const;
inline void set_map(Map* value);
inline HeapObject** map_slot();
// The no-write-barrier version. This is OK if the object is white and in
// new space, or if the value is an immortal immutable object, like the maps
// of primitive (non-JS) objects like strings, heap numbers etc.
inline void set_map_no_write_barrier(Map* value);
// Get the map using acquire load.
inline Map* synchronized_map();
inline MapWord synchronized_map_word() const;
// Set the map using release store
inline void synchronized_set_map(Map* value);
inline void synchronized_set_map_word(MapWord map_word);
// Initialize the map immediately after the object is allocated.
// Do not use this outside Heap.
inline void set_map_after_allocation(
Map* value, WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
// During garbage collection, the map word of a heap object does not
// necessarily contain a map pointer.
inline MapWord map_word() const;
inline void set_map_word(MapWord map_word);
// The Heap the object was allocated in. Used also to access Isolate.
inline Heap* GetHeap() const;
// Convenience method to get current isolate.
inline Isolate* GetIsolate() const;
#define IS_TYPE_FUNCTION_DECL(Type) INLINE(bool Is##Type() const);
HEAP_OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
#undef IS_TYPE_FUNCTION_DECL
#define IS_TYPE_FUNCTION_DECL(Type, Value) \
INLINE(bool Is##Type(Isolate* isolate) const);
ODDBALL_LIST(IS_TYPE_FUNCTION_DECL)
#undef IS_TYPE_FUNCTION_DECL
INLINE(bool IsNullOrUndefined(Isolate* isolate) const);
#define DECLARE_STRUCT_PREDICATE(NAME, Name, name) \
INLINE(bool Is##Name() const);
STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
#undef DECLARE_STRUCT_PREDICATE
// Converts an address to a HeapObject pointer.
static inline HeapObject* FromAddress(Address address) {
DCHECK_TAG_ALIGNED(address);
return reinterpret_cast<HeapObject*>(address + kHeapObjectTag);
}
// Returns the address of this HeapObject.
inline Address address() {
return reinterpret_cast<Address>(this) - kHeapObjectTag;
}
// Iterates over pointers contained in the object (including the Map).
// If it's not performance critical iteration use the non-templatized
// version.
void Iterate(ObjectVisitor* v);
template <typename ObjectVisitor>
inline void IterateFast(ObjectVisitor* v);
// Iterates over all pointers contained in the object except the
// first map pointer. The object type is given in the first
// parameter. This function does not access the map pointer in the
// object, and so is safe to call while the map pointer is modified.
// If it's not performance critical iteration use the non-templatized
// version.
void IterateBody(ObjectVisitor* v);
void IterateBody(InstanceType type, int object_size, ObjectVisitor* v);
template <typename ObjectVisitor>
inline void IterateBodyFast(ObjectVisitor* v);
template <typename ObjectVisitor>
inline void IterateBodyFast(InstanceType type, int object_size,
ObjectVisitor* v);
// Returns true if the object contains a tagged value at given offset.
// It is used for invalid slots filtering. If the offset points outside
// of the object or to the map word, the result is UNDEFINED (!!!).
bool IsValidSlot(int offset);
// Returns the heap object's size in bytes
inline int Size();
// Given a heap object's map pointer, returns the heap size in bytes
// Useful when the map pointer field is used for other purposes.
// GC internal.
inline int SizeFromMap(Map* map);
// Returns the field at offset in obj, as a read/write Object* reference.
// Does no checking, and is safe to use during GC, while maps are invalid.
// Does not invoke write barrier, so should only be assigned to
// during marking GC.
static inline Object** RawField(HeapObject* obj, int offset);
// Adds the |code| object related to |name| to the code cache of this map. If
// this map is a dictionary map that is shared, the map copied and installed
// onto the object.
static void UpdateMapCodeCache(Handle<HeapObject> object,
Handle<Name> name,
Handle<Code> code);
DECLARE_CAST(HeapObject)
// Return the write barrier mode for this. Callers of this function
// must be able to present a reference to an DisallowHeapAllocation
// object as a sign that they are not going to use this function
// from code that allocates and thus invalidates the returned write
// barrier mode.
inline WriteBarrierMode GetWriteBarrierMode(
const DisallowHeapAllocation& promise);
// Dispatched behavior.
void HeapObjectShortPrint(std::ostream& os); // NOLINT
#ifdef OBJECT_PRINT
void PrintHeader(std::ostream& os, const char* id); // NOLINT
#endif
DECLARE_PRINTER(HeapObject)
DECLARE_VERIFIER(HeapObject)
#ifdef VERIFY_HEAP
inline void VerifyObjectField(int offset);
inline void VerifySmiField(int offset);
// Verify a pointer is a valid HeapObject pointer that points to object
// areas in the heap.
static void VerifyHeapPointer(Object* p);
#endif
inline AllocationAlignment RequiredAlignment();
// Layout description.
// First field in a heap object is map.
static const int kMapOffset = Object::kHeaderSize;
static const int kHeaderSize = kMapOffset + kPointerSize;
STATIC_ASSERT(kMapOffset == Internals::kHeapObjectMapOffset);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(HeapObject);
};
template <int start_offset, int end_offset, int size>
class FixedBodyDescriptor;
template <int start_offset>
class FlexibleBodyDescriptor;
// The HeapNumber class describes heap allocated numbers that cannot be
// represented in a Smi (small integer)
class HeapNumber: public HeapObject {
public:
// [value]: number value.
inline double value() const;
inline void set_value(double value);
inline uint64_t value_as_bits() const;
inline void set_value_as_bits(uint64_t bits);
DECLARE_CAST(HeapNumber)
// Dispatched behavior.
bool HeapNumberBooleanValue();
V8_EXPORT_PRIVATE void HeapNumberPrint(std::ostream& os); // NOLINT
DECLARE_VERIFIER(HeapNumber)
inline int get_exponent();
inline int get_sign();
// Layout description.
static const int kValueOffset = HeapObject::kHeaderSize;
// IEEE doubles are two 32 bit words. The first is just mantissa, the second
// is a mixture of sign, exponent and mantissa. The offsets of two 32 bit
// words within double numbers are endian dependent and they are set
// accordingly.
#if defined(V8_TARGET_LITTLE_ENDIAN)
static const int kMantissaOffset = kValueOffset;
static const int kExponentOffset = kValueOffset + 4;
#elif defined(V8_TARGET_BIG_ENDIAN)
static const int kMantissaOffset = kValueOffset + 4;
static const int kExponentOffset = kValueOffset;
#else
#error Unknown byte ordering
#endif
static const int kSize = kValueOffset + kDoubleSize;
static const uint32_t kSignMask = 0x80000000u;
static const uint32_t kExponentMask = 0x7ff00000u;
static const uint32_t kMantissaMask = 0xfffffu;
static const int kMantissaBits = 52;
static const int kExponentBits = 11;
static const int kExponentBias = 1023;
static const int kExponentShift = 20;
static const int kInfinityOrNanExponent =
(kExponentMask >> kExponentShift) - kExponentBias;
static const int kMantissaBitsInTopWord = 20;
static const int kNonMantissaBitsInTopWord = 12;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(HeapNumber);
};
enum EnsureElementsMode {
DONT_ALLOW_DOUBLE_ELEMENTS,
ALLOW_COPIED_DOUBLE_ELEMENTS,
ALLOW_CONVERTED_DOUBLE_ELEMENTS
};
// Indicator for one component of an AccessorPair.
enum AccessorComponent {
ACCESSOR_GETTER,
ACCESSOR_SETTER
};
enum class GetKeysConversion { kKeepNumbers, kConvertToString };
enum class KeyCollectionMode {
kOwnOnly = static_cast<int>(v8::KeyCollectionMode::kOwnOnly),
kIncludePrototypes =
static_cast<int>(v8::KeyCollectionMode::kIncludePrototypes)
};
enum class AllocationSiteUpdateMode { kUpdate, kCheckOnly };
// JSReceiver includes types on which properties can be defined, i.e.,
// JSObject and JSProxy.
class JSReceiver: public HeapObject {
public:
// [properties]: Backing storage for properties.
// properties is a FixedArray in the fast case and a Dictionary in the
// slow case.
DECL_ACCESSORS(properties, FixedArray) // Get and set fast properties.
inline void initialize_properties();
inline bool HasFastProperties();
// Gets slow properties for non-global objects.
inline NameDictionary* property_dictionary();
// Deletes an existing named property in a normalized object.
static void DeleteNormalizedProperty(Handle<JSReceiver> object,
Handle<Name> name, int entry);
DECLARE_CAST(JSReceiver)
// ES6 section 7.1.1 ToPrimitive
MUST_USE_RESULT static MaybeHandle<Object> ToPrimitive(
Handle<JSReceiver> receiver,
ToPrimitiveHint hint = ToPrimitiveHint::kDefault);
// ES6 section 7.1.1.1 OrdinaryToPrimitive
MUST_USE_RESULT static MaybeHandle<Object> OrdinaryToPrimitive(
Handle<JSReceiver> receiver, OrdinaryToPrimitiveHint hint);
static MaybeHandle<Context> GetFunctionRealm(Handle<JSReceiver> receiver);
// Get the first non-hidden prototype.
static inline MaybeHandle<Object> GetPrototype(Isolate* isolate,
Handle<JSReceiver> receiver);
MUST_USE_RESULT static Maybe<bool> HasInPrototypeChain(
Isolate* isolate, Handle<JSReceiver> object, Handle<Object> proto);
// Reads all enumerable own properties of source and adds them to
// target, using either Set or CreateDataProperty depending on the
// use_set argument. This only copies values not present in the
// maybe_excluded_properties list.
MUST_USE_RESULT static Maybe<bool> SetOrCopyDataProperties(
Isolate* isolate, Handle<JSReceiver> target, Handle<Object> source,
const ScopedVector<Handle<Object>>* excluded_properties = nullptr,
bool use_set = true);
// Implementation of [[HasProperty]], ECMA-262 5th edition, section 8.12.6.
MUST_USE_RESULT static Maybe<bool> HasProperty(LookupIterator* it);
MUST_USE_RESULT static inline Maybe<bool> HasProperty(
Handle<JSReceiver> object, Handle<Name> name);
MUST_USE_RESULT static inline Maybe<bool> HasElement(
Handle<JSReceiver> object, uint32_t index);
MUST_USE_RESULT static inline Maybe<bool> HasOwnProperty(
Handle<JSReceiver> object, Handle<Name> name);
MUST_USE_RESULT static inline Maybe<bool> HasOwnProperty(
Handle<JSReceiver> object, uint32_t index);
MUST_USE_RESULT static inline MaybeHandle<Object> GetProperty(
Isolate* isolate, Handle<JSReceiver> receiver, const char* key);
MUST_USE_RESULT static inline MaybeHandle<Object> GetProperty(
Handle<JSReceiver> receiver, Handle<Name> name);
MUST_USE_RESULT static inline MaybeHandle<Object> GetElement(
Isolate* isolate, Handle<JSReceiver> receiver, uint32_t index);
// Implementation of ES6 [[Delete]]
MUST_USE_RESULT static Maybe<bool> DeletePropertyOrElement(
Handle<JSReceiver> object, Handle<Name> name,
LanguageMode language_mode = SLOPPY);
MUST_USE_RESULT static Maybe<bool> DeleteProperty(
Handle<JSReceiver> object, Handle<Name> name,
LanguageMode language_mode = SLOPPY);
MUST_USE_RESULT static Maybe<bool> DeleteProperty(LookupIterator* it,
LanguageMode language_mode);
MUST_USE_RESULT static Maybe<bool> DeleteElement(
Handle<JSReceiver> object, uint32_t index,
LanguageMode language_mode = SLOPPY);
MUST_USE_RESULT static Object* DefineProperty(Isolate* isolate,
Handle<Object> object,
Handle<Object> name,
Handle<Object> attributes);
MUST_USE_RESULT static MaybeHandle<Object> DefineProperties(
Isolate* isolate, Handle<Object> object, Handle<Object> properties);
// "virtual" dispatcher to the correct [[DefineOwnProperty]] implementation.
MUST_USE_RESULT static Maybe<bool> DefineOwnProperty(
Isolate* isolate, Handle<JSReceiver> object, Handle<Object> key,
PropertyDescriptor* desc, ShouldThrow should_throw);
// ES6 7.3.4 (when passed DONT_THROW)
MUST_USE_RESULT static Maybe<bool> CreateDataProperty(
LookupIterator* it, Handle<Object> value, ShouldThrow should_throw);
// ES6 9.1.6.1
MUST_USE_RESULT static Maybe<bool> OrdinaryDefineOwnProperty(
Isolate* isolate, Handle<JSObject> object, Handle<Object> key,
PropertyDescriptor* desc, ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> OrdinaryDefineOwnProperty(
LookupIterator* it, PropertyDescriptor* desc, ShouldThrow should_throw);
// ES6 9.1.6.2
MUST_USE_RESULT static Maybe<bool> IsCompatiblePropertyDescriptor(
Isolate* isolate, bool extensible, PropertyDescriptor* desc,
PropertyDescriptor* current, Handle<Name> property_name,
ShouldThrow should_throw);
// ES6 9.1.6.3
// |it| can be NULL in cases where the ES spec passes |undefined| as the
// receiver. Exactly one of |it| and |property_name| must be provided.
MUST_USE_RESULT static Maybe<bool> ValidateAndApplyPropertyDescriptor(
Isolate* isolate, LookupIterator* it, bool extensible,
PropertyDescriptor* desc, PropertyDescriptor* current,
ShouldThrow should_throw, Handle<Name> property_name = Handle<Name>());
V8_EXPORT_PRIVATE MUST_USE_RESULT static Maybe<bool> GetOwnPropertyDescriptor(
Isolate* isolate, Handle<JSReceiver> object, Handle<Object> key,
PropertyDescriptor* desc);
MUST_USE_RESULT static Maybe<bool> GetOwnPropertyDescriptor(
LookupIterator* it, PropertyDescriptor* desc);
typedef PropertyAttributes IntegrityLevel;
// ES6 7.3.14 (when passed DONT_THROW)
// 'level' must be SEALED or FROZEN.
MUST_USE_RESULT static Maybe<bool> SetIntegrityLevel(
Handle<JSReceiver> object, IntegrityLevel lvl, ShouldThrow should_throw);
// ES6 7.3.15
// 'level' must be SEALED or FROZEN.
MUST_USE_RESULT static Maybe<bool> TestIntegrityLevel(
Handle<JSReceiver> object, IntegrityLevel lvl);
// ES6 [[PreventExtensions]] (when passed DONT_THROW)
MUST_USE_RESULT static Maybe<bool> PreventExtensions(
Handle<JSReceiver> object, ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> IsExtensible(Handle<JSReceiver> object);
// Returns the class name ([[Class]] property in the specification).
V8_EXPORT_PRIVATE String* class_name();
// Returns the constructor name (the name (possibly, inferred name) of the
// function that was used to instantiate the object).
static Handle<String> GetConstructorName(Handle<JSReceiver> receiver);
Handle<Context> GetCreationContext();
MUST_USE_RESULT static inline Maybe<PropertyAttributes> GetPropertyAttributes(
Handle<JSReceiver> object, Handle<Name> name);
MUST_USE_RESULT static inline Maybe<PropertyAttributes>
GetOwnPropertyAttributes(Handle<JSReceiver> object, Handle<Name> name);
MUST_USE_RESULT static inline Maybe<PropertyAttributes>
GetOwnPropertyAttributes(Handle<JSReceiver> object, uint32_t index);
MUST_USE_RESULT static inline Maybe<PropertyAttributes> GetElementAttributes(
Handle<JSReceiver> object, uint32_t index);
MUST_USE_RESULT static inline Maybe<PropertyAttributes>
GetOwnElementAttributes(Handle<JSReceiver> object, uint32_t index);
MUST_USE_RESULT static Maybe<PropertyAttributes> GetPropertyAttributes(
LookupIterator* it);
// Set the object's prototype (only JSReceiver and null are allowed values).
MUST_USE_RESULT static Maybe<bool> SetPrototype(Handle<JSReceiver> object,
Handle<Object> value,
bool from_javascript,
ShouldThrow should_throw);
inline static Handle<Object> GetDataProperty(Handle<JSReceiver> object,
Handle<Name> name);
static Handle<Object> GetDataProperty(LookupIterator* it);
// Retrieves a permanent object identity hash code. The undefined value might
// be returned in case no hash was created yet.
static inline Object* GetIdentityHash(Isolate* isolate,
Handle<JSReceiver> object);
// Retrieves a permanent object identity hash code. May create and store a
// hash code if needed and none exists.
inline static Smi* GetOrCreateIdentityHash(Isolate* isolate,
Handle<JSReceiver> object);
// ES6 [[OwnPropertyKeys]] (modulo return type)
MUST_USE_RESULT static inline MaybeHandle<FixedArray> OwnPropertyKeys(
Handle<JSReceiver> object);
MUST_USE_RESULT static MaybeHandle<FixedArray> GetOwnValues(
Handle<JSReceiver> object, PropertyFilter filter);
MUST_USE_RESULT static MaybeHandle<FixedArray> GetOwnEntries(
Handle<JSReceiver> object, PropertyFilter filter);
// Layout description.
static const int kPropertiesOffset = HeapObject::kHeaderSize;
static const int kHeaderSize = HeapObject::kHeaderSize + kPointerSize;
bool HasProxyInPrototype(Isolate* isolate);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSReceiver);
};
// The JSObject describes real heap allocated JavaScript objects with
// properties.
// Note that the map of JSObject changes during execution to enable inline
// caching.
class JSObject: public JSReceiver {
public:
static bool IsUnmodifiedApiObject(Object** o);
static MUST_USE_RESULT MaybeHandle<JSObject> New(
Handle<JSFunction> constructor, Handle<JSReceiver> new_target,
Handle<AllocationSite> site = Handle<AllocationSite>::null());
// Gets global object properties.
inline GlobalDictionary* global_dictionary();
static MaybeHandle<Context> GetFunctionRealm(Handle<JSObject> object);
// [elements]: The elements (properties with names that are integers).
//
// Elements can be in two general modes: fast and slow. Each mode
// corresponds to a set of object representations of elements that
// have something in common.
//
// In the fast mode elements is a FixedArray and so each element can
// be quickly accessed. This fact is used in the generated code. The
// elements array can have one of three maps in this mode:
// fixed_array_map, sloppy_arguments_elements_map or
// fixed_cow_array_map (for copy-on-write arrays). In the latter case
// the elements array may be shared by a few objects and so before
// writing to any element the array must be copied. Use
// EnsureWritableFastElements in this case.
//
// In the slow mode the elements is either a NumberDictionary, a
// FixedArray parameter map for a (sloppy) arguments object.
DECL_ACCESSORS(elements, FixedArrayBase)
inline void initialize_elements();
static void ResetElements(Handle<JSObject> object);
static inline void SetMapAndElements(Handle<JSObject> object,
Handle<Map> map,
Handle<FixedArrayBase> elements);
inline ElementsKind GetElementsKind();
ElementsAccessor* GetElementsAccessor();
// Returns true if an object has elements of FAST_SMI_ELEMENTS ElementsKind.
inline bool HasFastSmiElements();
// Returns true if an object has elements of FAST_ELEMENTS ElementsKind.
inline bool HasFastObjectElements();
// Returns true if an object has elements of FAST_ELEMENTS or
// FAST_SMI_ONLY_ELEMENTS.
inline bool HasFastSmiOrObjectElements();
// Returns true if an object has any of the fast elements kinds.
inline bool HasFastElements();
// Returns true if an object has elements of FAST_DOUBLE_ELEMENTS
// ElementsKind.
inline bool HasFastDoubleElements();
// Returns true if an object has elements of FAST_HOLEY_*_ELEMENTS
// ElementsKind.
inline bool HasFastHoleyElements();
inline bool HasSloppyArgumentsElements();
inline bool HasStringWrapperElements();
inline bool HasDictionaryElements();
inline bool HasFixedTypedArrayElements();
inline bool HasFixedUint8ClampedElements();
inline bool HasFixedArrayElements();
inline bool HasFixedInt8Elements();
inline bool HasFixedUint8Elements();
inline bool HasFixedInt16Elements();
inline bool HasFixedUint16Elements();
inline bool HasFixedInt32Elements();
inline bool HasFixedUint32Elements();
inline bool HasFixedFloat32Elements();
inline bool HasFixedFloat64Elements();
inline bool HasFastArgumentsElements();
inline bool HasSlowArgumentsElements();
inline bool HasFastStringWrapperElements();
inline bool HasSlowStringWrapperElements();
bool HasEnumerableElements();
inline SeededNumberDictionary* element_dictionary(); // Gets slow elements.
// Requires: HasFastElements().
static void EnsureWritableFastElements(Handle<JSObject> object);
// Collects elements starting at index 0.
// Undefined values are placed after non-undefined values.
// Returns the number of non-undefined values.
static Handle<Object> PrepareElementsForSort(Handle<JSObject> object,
uint32_t limit);
// As PrepareElementsForSort, but only on objects where elements is
// a dictionary, and it will stay a dictionary. Collates undefined and
// unexisting elements below limit from position zero of the elements.
static Handle<Object> PrepareSlowElementsForSort(Handle<JSObject> object,
uint32_t limit);
MUST_USE_RESULT static Maybe<bool> SetPropertyWithInterceptor(
LookupIterator* it, ShouldThrow should_throw, Handle<Object> value);
// The API currently still wants DefineOwnPropertyIgnoreAttributes to convert
// AccessorInfo objects to data fields. We allow FORCE_FIELD as an exception
// to the default behavior that calls the setter.
enum AccessorInfoHandling { FORCE_FIELD, DONT_FORCE_FIELD };
MUST_USE_RESULT static MaybeHandle<Object> DefineOwnPropertyIgnoreAttributes(
LookupIterator* it, Handle<Object> value, PropertyAttributes attributes,
AccessorInfoHandling handling = DONT_FORCE_FIELD);
MUST_USE_RESULT static Maybe<bool> DefineOwnPropertyIgnoreAttributes(
LookupIterator* it, Handle<Object> value, PropertyAttributes attributes,
ShouldThrow should_throw,
AccessorInfoHandling handling = DONT_FORCE_FIELD);
MUST_USE_RESULT static MaybeHandle<Object> SetOwnPropertyIgnoreAttributes(
Handle<JSObject> object, Handle<Name> name, Handle<Object> value,
PropertyAttributes attributes);
MUST_USE_RESULT static MaybeHandle<Object> SetOwnElementIgnoreAttributes(
Handle<JSObject> object, uint32_t index, Handle<Object> value,
PropertyAttributes attributes);
// Equivalent to one of the above depending on whether |name| can be converted
// to an array index.
MUST_USE_RESULT static MaybeHandle<Object>
DefinePropertyOrElementIgnoreAttributes(Handle<JSObject> object,
Handle<Name> name,
Handle<Object> value,
PropertyAttributes attributes = NONE);
// Adds or reconfigures a property to attributes NONE. It will fail when it
// cannot.
MUST_USE_RESULT static Maybe<bool> CreateDataProperty(
LookupIterator* it, Handle<Object> value,
ShouldThrow should_throw = DONT_THROW);
static void AddProperty(Handle<JSObject> object, Handle<Name> name,
Handle<Object> value, PropertyAttributes attributes);
MUST_USE_RESULT static Maybe<bool> AddDataElement(
Handle<JSObject> receiver, uint32_t index, Handle<Object> value,
PropertyAttributes attributes, ShouldThrow should_throw);
MUST_USE_RESULT static MaybeHandle<Object> AddDataElement(
Handle<JSObject> receiver, uint32_t index, Handle<Object> value,
PropertyAttributes attributes);
// Extend the receiver with a single fast property appeared first in the
// passed map. This also extends the property backing store if necessary.
static void AllocateStorageForMap(Handle<JSObject> object, Handle<Map> map);
// Migrates the given object to a map whose field representations are the
// lowest upper bound of all known representations for that field.
static void MigrateInstance(Handle<JSObject> instance);
// Migrates the given object only if the target map is already available,
// or returns false if such a map is not yet available.
static bool TryMigrateInstance(Handle<JSObject> instance);
// Sets the property value in a normalized object given (key, value, details).
// Handles the special representation of JS global objects.
static void SetNormalizedProperty(Handle<JSObject> object, Handle<Name> name,
Handle<Object> value,
PropertyDetails details);
static void SetDictionaryElement(Handle<JSObject> object, uint32_t index,
Handle<Object> value,
PropertyAttributes attributes);
static void SetDictionaryArgumentsElement(Handle<JSObject> object,
uint32_t index,
Handle<Object> value,
PropertyAttributes attributes);
static void OptimizeAsPrototype(Handle<JSObject> object,
PrototypeOptimizationMode mode);
static void ReoptimizeIfPrototype(Handle<JSObject> object);
static void MakePrototypesFast(Handle<Object> receiver,
WhereToStart where_to_start, Isolate* isolate);
static void LazyRegisterPrototypeUser(Handle<Map> user, Isolate* isolate);
static void UpdatePrototypeUserRegistration(Handle<Map> old_map,
Handle<Map> new_map,
Isolate* isolate);
static bool UnregisterPrototypeUser(Handle<Map> user, Isolate* isolate);
static void InvalidatePrototypeChains(Map* map);
// Updates prototype chain tracking information when an object changes its
// map from |old_map| to |new_map|.
static void NotifyMapChange(Handle<Map> old_map, Handle<Map> new_map,
Isolate* isolate);
// Utility used by many Array builtins and runtime functions
static inline bool PrototypeHasNoElements(Isolate* isolate, JSObject* object);
// Alternative implementation of WeakFixedArray::NullCallback.
class PrototypeRegistryCompactionCallback {
public:
static void Callback(Object* value, int old_index, int new_index);
};
// Retrieve interceptors.
inline InterceptorInfo* GetNamedInterceptor();
inline InterceptorInfo* GetIndexedInterceptor();
// Used from JSReceiver.
MUST_USE_RESULT static Maybe<PropertyAttributes>
GetPropertyAttributesWithInterceptor(LookupIterator* it);
MUST_USE_RESULT static Maybe<PropertyAttributes>
GetPropertyAttributesWithFailedAccessCheck(LookupIterator* it);
// Defines an AccessorPair property on the given object.
// TODO(mstarzinger): Rename to SetAccessor().
static MaybeHandle<Object> DefineAccessor(Handle<JSObject> object,
Handle<Name> name,
Handle<Object> getter,
Handle<Object> setter,
PropertyAttributes attributes);
static MaybeHandle<Object> DefineAccessor(LookupIterator* it,
Handle<Object> getter,
Handle<Object> setter,
PropertyAttributes attributes);
// Defines an AccessorInfo property on the given object.
MUST_USE_RESULT static MaybeHandle<Object> SetAccessor(
Handle<JSObject> object,
Handle<AccessorInfo> info);
// The result must be checked first for exceptions. If there's no exception,
// the output parameter |done| indicates whether the interceptor has a result
// or not.
MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithInterceptor(
LookupIterator* it, bool* done);
static void ValidateElements(Handle<JSObject> object);
// Makes sure that this object can contain HeapObject as elements.
static inline void EnsureCanContainHeapObjectElements(Handle<JSObject> obj);
// Makes sure that this object can contain the specified elements.
static inline void EnsureCanContainElements(
Handle<JSObject> object,
Object** elements,
uint32_t count,
EnsureElementsMode mode);
static inline void EnsureCanContainElements(
Handle<JSObject> object,
Handle<FixedArrayBase> elements,
uint32_t length,
EnsureElementsMode mode);
static void EnsureCanContainElements(
Handle<JSObject> object,
Arguments* arguments,
uint32_t first_arg,
uint32_t arg_count,
EnsureElementsMode mode);
// Would we convert a fast elements array to dictionary mode given
// an access at key?
bool WouldConvertToSlowElements(uint32_t index);
static const uint32_t kMinAddedElementsCapacity = 16;
// Computes the new capacity when expanding the elements of a JSObject.
static uint32_t NewElementsCapacity(uint32_t old_capacity) {
// (old_capacity + 50%) + kMinAddedElementsCapacity
return old_capacity + (old_capacity >> 1) + kMinAddedElementsCapacity;
}
// These methods do not perform access checks!
template <AllocationSiteUpdateMode update_or_check =
AllocationSiteUpdateMode::kUpdate>
static bool UpdateAllocationSite(Handle<JSObject> object,
ElementsKind to_kind);
// Lookup interceptors are used for handling properties controlled by host
// objects.
inline bool HasNamedInterceptor();
inline bool HasIndexedInterceptor();
// Support functions for v8 api (needed for correct interceptor behavior).
MUST_USE_RESULT static Maybe<bool> HasRealNamedProperty(
Handle<JSObject> object, Handle<Name> name);
MUST_USE_RESULT static Maybe<bool> HasRealElementProperty(
Handle<JSObject> object, uint32_t index);
MUST_USE_RESULT static Maybe<bool> HasRealNamedCallbackProperty(
Handle<JSObject> object, Handle<Name> name);
// Get the header size for a JSObject. Used to compute the index of
// embedder fields as well as the number of embedder fields.
static inline int GetHeaderSize(InstanceType instance_type);
inline int GetHeaderSize();
static inline int GetEmbedderFieldCount(Map* map);
inline int GetEmbedderFieldCount();
inline int GetEmbedderFieldOffset(int index);
inline Object* GetEmbedderField(int index);
inline void SetEmbedderField(int index, Object* value);
inline void SetEmbedderField(int index, Smi* value);
bool WasConstructedFromApiFunction();
// Returns a new map with all transitions dropped from the object's current
// map and the ElementsKind set.
static Handle<Map> GetElementsTransitionMap(Handle<JSObject> object,
ElementsKind to_kind);
static void TransitionElementsKind(Handle<JSObject> object,
ElementsKind to_kind);
// Always use this to migrate an object to a new map.
// |expected_additional_properties| is only used for fast-to-slow transitions
// and ignored otherwise.
static void MigrateToMap(Handle<JSObject> object, Handle<Map> new_map,
int expected_additional_properties = 0);
// Forces a prototype without any of the checks that the regular SetPrototype
// would do.
static void ForceSetPrototype(Handle<JSObject> object, Handle<Object> proto);
// Convert the object to use the canonical dictionary
// representation. If the object is expected to have additional properties
// added this number can be indicated to have the backing store allocated to
// an initial capacity for holding these properties.
static void NormalizeProperties(Handle<JSObject> object,
PropertyNormalizationMode mode,
int expected_additional_properties,
const char* reason);
// Convert and update the elements backing store to be a
// SeededNumberDictionary dictionary. Returns the backing after conversion.
static Handle<SeededNumberDictionary> NormalizeElements(
Handle<JSObject> object);
void RequireSlowElements(SeededNumberDictionary* dictionary);
// Transform slow named properties to fast variants.
static void MigrateSlowToFast(Handle<JSObject> object,
int unused_property_fields, const char* reason);
inline bool IsUnboxedDoubleField(FieldIndex index);
// Access fast-case object properties at index.
static Handle<Object> FastPropertyAt(Handle<JSObject> object,
Representation representation,
FieldIndex index);
inline Object* RawFastPropertyAt(FieldIndex index);
inline double RawFastDoublePropertyAt(FieldIndex index);
inline uint64_t RawFastDoublePropertyAsBitsAt(FieldIndex index);
inline void FastPropertyAtPut(FieldIndex index, Object* value);
inline void RawFastPropertyAtPut(FieldIndex index, Object* value);
inline void RawFastDoublePropertyAsBitsAtPut(FieldIndex index, uint64_t bits);
inline void WriteToField(int descriptor, PropertyDetails details,
Object* value);
// Access to in object properties.
inline int GetInObjectPropertyOffset(int index);
inline Object* InObjectPropertyAt(int index);
inline Object* InObjectPropertyAtPut(int index,
Object* value,
WriteBarrierMode mode
= UPDATE_WRITE_BARRIER);
// Set the object's prototype (only JSReceiver and null are allowed values).
MUST_USE_RESULT static Maybe<bool> SetPrototype(Handle<JSObject> object,
Handle<Object> value,
bool from_javascript,
ShouldThrow should_throw);
// Makes the object prototype immutable
// Never called from JavaScript
static void SetImmutableProto(Handle<JSObject> object);
// Initializes the body starting at |start_offset|. It is responsibility of
// the caller to initialize object header. Fill the pre-allocated fields with
// pre_allocated_value and the rest with filler_value.
// Note: this call does not update write barrier, the caller is responsible
// to ensure that |filler_value| can be collected without WB here.
inline void InitializeBody(Map* map, int start_offset,
Object* pre_allocated_value, Object* filler_value);
// Check whether this object references another object
bool ReferencesObject(Object* obj);
MUST_USE_RESULT static Maybe<bool> PreventExtensions(
Handle<JSObject> object, ShouldThrow should_throw);
static bool IsExtensible(Handle<JSObject> object);
// Copy object.
enum DeepCopyHints { kNoHints = 0, kObjectIsShallow = 1 };
MUST_USE_RESULT static MaybeHandle<JSObject> DeepCopy(
Handle<JSObject> object,
AllocationSiteUsageContext* site_context,
DeepCopyHints hints = kNoHints);
MUST_USE_RESULT static MaybeHandle<JSObject> DeepWalk(
Handle<JSObject> object,
AllocationSiteCreationContext* site_context);
DECLARE_CAST(JSObject)
// Dispatched behavior.
void JSObjectShortPrint(StringStream* accumulator);
DECLARE_PRINTER(JSObject)
DECLARE_VERIFIER(JSObject)
#ifdef OBJECT_PRINT
bool PrintProperties(std::ostream& os); // NOLINT
void PrintElements(std::ostream& os); // NOLINT
#endif
#if defined(DEBUG) || defined(OBJECT_PRINT)
void PrintTransitions(std::ostream& os); // NOLINT
#endif
static void PrintElementsTransition(
FILE* file, Handle<JSObject> object,
ElementsKind from_kind, Handle<FixedArrayBase> from_elements,
ElementsKind to_kind, Handle<FixedArrayBase> to_elements);
void PrintInstanceMigration(FILE* file, Map* original_map, Map* new_map);
#ifdef DEBUG
// Structure for collecting spill information about JSObjects.
class SpillInformation {
public:
void Clear();
void Print();
int number_of_objects_;
int number_of_objects_with_fast_properties_;
int number_of_objects_with_fast_elements_;
int number_of_fast_used_fields_;
int number_of_fast_unused_fields_;
int number_of_slow_used_properties_;
int number_of_slow_unused_properties_;
int number_of_fast_used_elements_;
int number_of_fast_unused_elements_;
int number_of_slow_used_elements_;
int number_of_slow_unused_elements_;
};
void IncrementSpillStatistics(SpillInformation* info);
#endif
#ifdef VERIFY_HEAP
// If a GC was caused while constructing this object, the elements pointer
// may point to a one pointer filler map. The object won't be rooted, but
// our heap verification code could stumble across it.
bool ElementsAreSafeToExamine();
#endif
Object* SlowReverseLookup(Object* value);
// Maximal number of elements (numbered 0 .. kMaxElementCount - 1).
// Also maximal value of JSArray's length property.
static const uint32_t kMaxElementCount = 0xffffffffu;
// Constants for heuristics controlling conversion of fast elements
// to slow elements.
// Maximal gap that can be introduced by adding an element beyond
// the current elements length.
static const uint32_t kMaxGap = 1024;
// Maximal length of fast elements array that won't be checked for
// being dense enough on expansion.
static const int kMaxUncheckedFastElementsLength = 5000;
// Same as above but for old arrays. This limit is more strict. We
// don't want to be wasteful with long lived objects.
static const int kMaxUncheckedOldFastElementsLength = 500;
// This constant applies only to the initial map of "global.Object" and
// not to arbitrary other JSObject maps.
static const int kInitialGlobalObjectUnusedPropertiesCount = 4;
static const int kMaxInstanceSize = 255 * kPointerSize;
// When extending the backing storage for property values, we increase
// its size by more than the 1 entry necessary, so sequentially adding fields
// to the same object requires fewer allocations and copies.
static const int kFieldsAdded = 3;
// Layout description.
static const int kElementsOffset = JSReceiver::kHeaderSize;
static const int kHeaderSize = kElementsOffset + kPointerSize;
STATIC_ASSERT(kHeaderSize == Internals::kJSObjectHeaderSize);
class BodyDescriptor;
class FastBodyDescriptor;
// Gets the number of currently used elements.
int GetFastElementsUsage();
static bool AllCanRead(LookupIterator* it);
static bool AllCanWrite(LookupIterator* it);
private:
friend class JSReceiver;
friend class Object;
// Used from Object::GetProperty().
MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithFailedAccessCheck(
LookupIterator* it);
MUST_USE_RESULT static Maybe<bool> SetPropertyWithFailedAccessCheck(
LookupIterator* it, Handle<Object> value, ShouldThrow should_throw);
MUST_USE_RESULT static Maybe<bool> DeletePropertyWithInterceptor(
LookupIterator* it, ShouldThrow should_throw);
bool ReferencesObjectFromElements(FixedArray* elements,
ElementsKind kind,
Object* object);
static Object* GetIdentityHash(Isolate* isolate, Handle<JSObject> object);
static Smi* GetOrCreateIdentityHash(Isolate* isolate,
Handle<JSObject> object);
// Helper for fast versions of preventExtensions, seal, and freeze.
// attrs is one of NONE, SEALED, or FROZEN (depending on the operation).
template <PropertyAttributes attrs>
MUST_USE_RESULT static Maybe<bool> PreventExtensionsWithTransition(
Handle<JSObject> object, ShouldThrow should_throw);
DISALLOW_IMPLICIT_CONSTRUCTORS(JSObject);
};
// JSAccessorPropertyDescriptor is just a JSObject with a specific initial
// map. This initial map adds in-object properties for "get", "set",
// "enumerable" and "configurable" properties, as assigned by the
// FromPropertyDescriptor function for regular accessor properties.
class JSAccessorPropertyDescriptor: public JSObject {
public:
// Offsets of object fields.
static const int kGetOffset = JSObject::kHeaderSize;
static const int kSetOffset = kGetOffset + kPointerSize;
static const int kEnumerableOffset = kSetOffset + kPointerSize;
static const int kConfigurableOffset = kEnumerableOffset + kPointerSize;
static const int kSize = kConfigurableOffset + kPointerSize;
// Indices of in-object properties.
static const int kGetIndex = 0;
static const int kSetIndex = 1;
static const int kEnumerableIndex = 2;
static const int kConfigurableIndex = 3;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSAccessorPropertyDescriptor);
};
// JSDataPropertyDescriptor is just a JSObject with a specific initial map.
// This initial map adds in-object properties for "value", "writable",
// "enumerable" and "configurable" properties, as assigned by the
// FromPropertyDescriptor function for regular data properties.
class JSDataPropertyDescriptor: public JSObject {
public:
// Offsets of object fields.
static const int kValueOffset = JSObject::kHeaderSize;
static const int kWritableOffset = kValueOffset + kPointerSize;
static const int kEnumerableOffset = kWritableOffset + kPointerSize;
static const int kConfigurableOffset = kEnumerableOffset + kPointerSize;
static const int kSize = kConfigurableOffset + kPointerSize;
// Indices of in-object properties.
static const int kValueIndex = 0;
static const int kWritableIndex = 1;
static const int kEnumerableIndex = 2;
static const int kConfigurableIndex = 3;