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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 "include/v8-internal.h"
#include "include/v8.h"
#include "include/v8config.h"
#include "src/assert-scope.h"
#include "src/base/bits.h"
#include "src/base/build_config.h"
#include "src/base/flags.h"
#include "src/base/logging.h"
#include "src/checks.h"
#include "src/constants-arch.h"
#include "src/elements-kind.h"
#include "src/field-index.h"
#include "src/flags.h"
#include "src/message-template.h"
#include "src/objects-definitions.h"
#include "src/property-details.h"
#include "src/utils.h"
#ifdef V8_COMPRESS_POINTERS
#include "src/ptr-compr.h"
#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
// - JSV8BreakIterator // If V8_INTL_SUPPORT enabled.
// - JSCollator // If V8_INTL_SUPPORT enabled.
// - JSDateTimeFormat // If V8_INTL_SUPPORT enabled.
// - JSListFormat // If V8_INTL_SUPPORT enabled.
// - JSLocale // If V8_INTL_SUPPORT enabled.
// - JSNumberFormat // If V8_INTL_SUPPORT enabled.
// - JSPluralRules // If V8_INTL_SUPPORT enabled.
// - JSRelativeTimeFormat // If V8_INTL_SUPPORT enabled.
// - JSSegmentIterator // If V8_INTL_SUPPORT enabled.
// - JSSegmenter // If V8_INTL_SUPPORT enabled.
// - WasmExceptionObject
// - WasmGlobalObject
// - WasmInstanceObject
// - WasmMemoryObject
// - WasmModuleObject
// - WasmTableObject
// - JSProxy
// - FixedArrayBase
// - ByteArray
// - BytecodeArray
// - FixedArray
// - FrameArray
// - HashTable
// - Dictionary
// - StringTable
// - StringSet
// - CompilationCacheTable
// - MapCache
// - OrderedHashTable
// - OrderedHashSet
// - OrderedHashMap
// - FeedbackMetadata
// - TemplateList
// - TransitionArray
// - ScopeInfo
// - ModuleInfo
// - ScriptContextTable
// - FixedDoubleArray
// - Name
// - String
// - SeqString
// - SeqOneByteString
// - SeqTwoByteString
// - SlicedString
// - ConsString
// - ThinString
// - ExternalString
// - ExternalOneByteString
// - ExternalTwoByteString
// - InternalizedString
// - SeqInternalizedString
// - SeqOneByteInternalizedString
// - SeqTwoByteInternalizedString
// - ConsInternalizedString
// - ExternalInternalizedString
// - ExternalOneByteInternalizedString
// - ExternalTwoByteInternalizedString
// - Symbol
// - Context
// - NativeContext
// - HeapNumber
// - BigInt
// - Cell
// - DescriptorArray
// - PropertyCell
// - PropertyArray
// - Code
// - AbstractCode, a wrapper around Code or BytecodeArray
// - Map
// - Oddball
// - Foreign
// - SmallOrderedHashTable
// - SmallOrderedHashMap
// - SmallOrderedHashSet
// - SharedFunctionInfo
// - Struct
// - AccessorInfo
// - AsmWasmData
// - PromiseReaction
// - PromiseCapability
// - AccessorPair
// - AccessCheckInfo
// - InterceptorInfo
// - CallHandlerInfo
// - EnumCache
// - TemplateInfo
// - FunctionTemplateInfo
// - ObjectTemplateInfo
// - Script
// - DebugInfo
// - BreakPoint
// - BreakPointInfo
// - StackFrameInfo
// - SourcePositionTableWithFrameCache
// - CodeCache
// - PrototypeInfo
// - Microtask
// - CallbackTask
// - CallableTask
// - PromiseReactionJobTask
// - PromiseFulfillReactionJobTask
// - PromiseRejectReactionJobTask
// - PromiseResolveThenableJobTask
// - Module
// - ModuleInfoEntry
// - FeedbackCell
// - FeedbackVector
// - PreparseData
// - UncompiledData
// - UncompiledDataWithoutPreparseData
// - UncompiledDataWithPreparseData
//
// Formats of Object::ptr_:
// Smi: [31 bit signed int] 0
// HeapObject: [32 bit direct pointer] (4 byte aligned) | 01
namespace v8 {
namespace internal {
struct InliningPosition;
class PropertyDescriptorObject;
// 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 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
};
// 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;
// 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
};
// (Returns false whenever {result} is kUndefined.)
bool ComparisonResultToBool(Operation op, ComparisonResult result);
enum class OnNonExistent { kThrowReferenceError, kReturnUndefined };
class AbstractCode;
class AccessorPair;
class AccessCheckInfo;
class AllocationSite;
class ByteArray;
class Cell;
class ConsString;
class DependentCode;
class ElementsAccessor;
class EnumCache;
class FixedArrayBase;
class FixedDoubleArray;
class FreeSpace;
class FunctionLiteral;
class FunctionTemplateInfo;
class JSAsyncGeneratorObject;
class JSGlobalProxy;
class JSPromise;
class JSProxy;
class KeyAccumulator;
class LayoutDescriptor;
class LookupIterator;
class FieldType;
class Module;
class ModuleInfoEntry;
class MutableHeapNumber;
class ObjectHashTable;
class ObjectTemplateInfo;
class ObjectVisitor;
class PreparseData;
class PropertyArray;
class PropertyCell;
class PropertyDescriptor;
class PrototypeInfo;
class ReadOnlyRoots;
class RegExpMatchInfo;
class RootVisitor;
class SafepointEntry;
class ScriptContextTable;
class SharedFunctionInfo;
class StringStream;
class Symbol;
class FeedbackCell;
class FeedbackMetadata;
class FeedbackVector;
class UncompiledData;
class TemplateInfo;
class TransitionArray;
class TemplateList;
class WasmInstanceObject;
class WasmMemoryObject;
template <typename T>
class ZoneForwardList;
#ifdef OBJECT_PRINT
#define DECL_PRINTER(Name) void Name##Print(std::ostream& os); // NOLINT
#else
#define DECL_PRINTER(Name)
#endif
#define OBJECT_TYPE_LIST(V) \
V(Smi) \
V(LayoutDescriptor) \
V(HeapObject) \
V(Primitive) \
V(Number) \
V(Numeric)
#define HEAP_OBJECT_ORDINARY_TYPE_LIST_BASE(V) \
V(AbstractCode) \
V(AccessCheckNeeded) \
V(AllocationSite) \
V(ArrayList) \
V(BigInt) \
V(BigIntWrapper) \
V(ObjectBoilerplateDescription) \
V(Boolean) \
V(BooleanWrapper) \
V(BreakPoint) \
V(BreakPointInfo) \
V(ByteArray) \
V(BytecodeArray) \
V(CallHandlerInfo) \
V(Callable) \
V(Cell) \
V(ClassBoilerplate) \
V(Code) \
V(CodeDataContainer) \
V(CompilationCacheTable) \
V(ConsString) \
V(Constructor) \
V(Context) \
V(CoverageInfo) \
V(DataHandler) \
V(DeoptimizationData) \
V(DependentCode) \
V(DescriptorArray) \
V(EmbedderDataArray) \
V(EphemeronHashTable) \
V(EnumCache) \
V(ExternalOneByteString) \
V(ExternalString) \
V(ExternalTwoByteString) \
V(FeedbackCell) \
V(FeedbackMetadata) \
V(FeedbackVector) \
V(Filler) \
V(FixedArray) \
V(FixedArrayBase) \
V(FixedArrayExact) \
V(FixedBigInt64Array) \
V(FixedBigUint64Array) \
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(GlobalDictionary) \
V(HandlerTable) \
V(HeapNumber) \
V(InternalizedString) \
V(JSArgumentsObject) \
V(JSArgumentsObjectWithLength) \
V(JSArray) \
V(JSArrayBuffer) \
V(JSArrayBufferView) \
V(JSArrayIterator) \
V(JSAsyncFromSyncIterator) \
V(JSAsyncFunctionObject) \
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(JSProxy) \
V(JSReceiver) \
V(JSRegExp) \
V(JSRegExpResult) \
V(JSRegExpStringIterator) \
V(JSSet) \
V(JSSetIterator) \
V(JSSloppyArgumentsObject) \
V(JSStringIterator) \
V(JSTypedArray) \
V(JSValue) \
V(JSWeakCell) \
V(JSWeakRef) \
V(JSWeakCollection) \
V(JSWeakFactory) \
V(JSWeakFactoryCleanupIterator) \
V(JSWeakMap) \
V(JSWeakSet) \
V(LoadHandler) \
V(Map) \
V(MapCache) \
V(Microtask) \
V(ModuleInfo) \
V(MutableHeapNumber) \
V(Name) \
V(NameDictionary) \
V(NativeContext) \
V(NormalizedMapCache) \
V(NumberDictionary) \
V(NumberWrapper) \
V(ObjectHashSet) \
V(ObjectHashTable) \
V(Oddball) \
V(OrderedHashMap) \
V(OrderedHashSet) \
V(OrderedNameDictionary) \
V(PreparseData) \
V(PromiseReactionJobTask) \
V(PropertyArray) \
V(PropertyCell) \
V(PropertyDescriptorObject) \
V(RegExpMatchInfo) \
V(ScopeInfo) \
V(ScriptContextTable) \
V(ScriptWrapper) \
V(SeqOneByteString) \
V(SeqString) \
V(SeqTwoByteString) \
V(SharedFunctionInfo) \
V(SimpleNumberDictionary) \
V(SlicedString) \
V(SloppyArgumentsElements) \
V(SmallOrderedHashMap) \
V(SmallOrderedHashSet) \
V(SmallOrderedNameDictionary) \
V(SourcePositionTableWithFrameCache) \
V(StoreHandler) \
V(String) \
V(StringSet) \
V(StringTable) \
V(StringWrapper) \
V(Struct) \
V(Symbol) \
V(SymbolWrapper) \
V(TemplateInfo) \
V(TemplateList) \
V(TemplateObjectDescription) \
V(ThinString) \
V(TransitionArray) \
V(UncompiledData) \
V(UncompiledDataWithPreparseData) \
V(UncompiledDataWithoutPreparseData) \
V(Undetectable) \
V(UniqueName) \
V(WasmExceptionObject) \
V(WasmGlobalObject) \
V(WasmInstanceObject) \
V(WasmMemoryObject) \
V(WasmModuleObject) \
V(WasmTableObject) \
V(WeakFixedArray) \
V(WeakArrayList)
#ifdef V8_INTL_SUPPORT
#define HEAP_OBJECT_ORDINARY_TYPE_LIST(V) \
HEAP_OBJECT_ORDINARY_TYPE_LIST_BASE(V) \
V(JSV8BreakIterator) \
V(JSCollator) \
V(JSDateTimeFormat) \
V(JSListFormat) \
V(JSLocale) \
V(JSNumberFormat) \
V(JSPluralRules) \
V(JSRelativeTimeFormat) \
V(JSSegmentIterator) \
V(JSSegmenter)
#else
#define HEAP_OBJECT_ORDINARY_TYPE_LIST(V) HEAP_OBJECT_ORDINARY_TYPE_LIST_BASE(V)
#endif // V8_INTL_SUPPORT
#define HEAP_OBJECT_TEMPLATE_TYPE_LIST(V) \
V(Dictionary) \
V(HashTable)
#define HEAP_OBJECT_TYPE_LIST(V) \
HEAP_OBJECT_ORDINARY_TYPE_LIST(V) \
HEAP_OBJECT_TEMPLATE_TYPE_LIST(V)
#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 };
// TODO(mythria): Move this to a better place.
ShouldThrow GetShouldThrow(Isolate* isolate, Maybe<ShouldThrow> should_throw);
// 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.
// There must only be a single data member in Object: the Address ptr,
// containing the tagged heap pointer that this Object instance refers to.
// For a design overview, see https://goo.gl/Ph4CGz.
class Object {
public:
constexpr Object() : ptr_(kNullAddress) {}
explicit constexpr Object(Address ptr) : ptr_(ptr) {}
// Make clang on Linux catch what MSVC complains about on Windows:
operator bool() const = delete;
bool operator==(const Object that) const { return this->ptr() == that.ptr(); }
bool operator!=(const Object that) const { return this->ptr() != that.ptr(); }
// Usage in std::set requires operator<.
bool operator<(const Object that) const { return this->ptr() < that.ptr(); }
// Returns the tagged "(heap) object pointer" representation of this object.
constexpr Address ptr() const { return ptr_; }
// These operator->() overloads are required for handlified code.
Object* operator->() { return this; }
const Object* operator->() const { return this; }
// Type testing.
bool IsObject() const { return true; }
#define IS_TYPE_FUNCTION_DECL(Type) V8_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
// Oddball checks are faster when they are raw pointer comparisons, so the
// isolate/read-only roots overloads should be preferred where possible.
#define IS_TYPE_FUNCTION_DECL(Type, Value) \
V8_INLINE bool Is##Type(Isolate* isolate) const; \
V8_INLINE bool Is##Type(ReadOnlyRoots roots) const; \
V8_INLINE bool Is##Type() const;
ODDBALL_LIST(IS_TYPE_FUNCTION_DECL)
#undef IS_TYPE_FUNCTION_DECL
V8_INLINE bool IsNullOrUndefined(Isolate* isolate) const;
V8_INLINE bool IsNullOrUndefined(ReadOnlyRoots roots) const;
V8_INLINE bool IsNullOrUndefined() const;
enum class Conversion { kToNumber, kToNumeric };
#define RETURN_FAILURE(isolate, should_throw, call) \
do { \
if ((should_throw) == kDontThrow) { \
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 MAYBE_ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, dst, call) \
do { \
Isolate* __isolate__ = (isolate); \
if (!(call).To(&dst)) { \
DCHECK(__isolate__->has_pending_exception()); \
return ReadOnlyRoots(__isolate__).exception(); \
} \
} while (false)
#define DECL_STRUCT_PREDICATE(NAME, Name, name) V8_INLINE bool Is##Name() const;
STRUCT_LIST(DECL_STRUCT_PREDICATE)
#undef DECL_STRUCT_PREDICATE
// ES6, #sec-isarray. NOT to be confused with %_IsArray.
V8_INLINE
V8_WARN_UNUSED_RESULT static Maybe<bool> IsArray(Handle<Object> object);
V8_INLINE bool IsHashTableBase() const;
V8_INLINE bool IsSmallOrderedHashTable() const;
// Extract the number.
inline double Number() const;
V8_INLINE bool IsNaN() const;
V8_INLINE bool IsMinusZero() const;
V8_EXPORT_PRIVATE bool ToInt32(int32_t* value);
inline bool ToUint32(uint32_t* value) const;
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();
// ECMA-262 9.2.
bool BooleanValue(Isolate* isolate);
// ES6 section 7.2.11 Abstract Relational Comparison
V8_WARN_UNUSED_RESULT static Maybe<ComparisonResult> Compare(
Isolate* isolate, Handle<Object> x, Handle<Object> y);
// ES6 section 7.2.12 Abstract Equality Comparison
V8_WARN_UNUSED_RESULT static Maybe<bool> Equals(Isolate* isolate,
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.
V8_WARN_UNUSED_RESULT static inline MaybeHandle<JSReceiver> ToObject(
Isolate* isolate, Handle<Object> object,
const char* method_name = nullptr);
V8_WARN_UNUSED_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.
V8_WARN_UNUSED_RESULT static MaybeHandle<JSReceiver> ConvertReceiver(
Isolate* isolate, Handle<Object> object);
// ES6 section 7.1.14 ToPropertyKey
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Name> ToName(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.1 ToPrimitive
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToPrimitive(
Handle<Object> input, ToPrimitiveHint hint = ToPrimitiveHint::kDefault);
// ES6 section 7.1.3 ToNumber
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToNumber(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToNumeric(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.4 ToInteger
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToInteger(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.5 ToInt32
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToInt32(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.6 ToUint32
V8_WARN_UNUSED_RESULT inline static MaybeHandle<Object> ToUint32(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.12 ToString
V8_WARN_UNUSED_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
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToPropertyKey(
Isolate* isolate, Handle<Object> value);
// ES6 section 7.1.15 ToLength
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToLength(
Isolate* isolate, Handle<Object> input);
// ES6 section 7.1.17 ToIndex
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> ToIndex(
Isolate* isolate, Handle<Object> input, MessageTemplate error_index);
// ES6 section 7.3.9 GetMethod
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> GetMethod(
Handle<JSReceiver> receiver, Handle<Name> name);
// ES6 section 7.3.17 CreateListFromArrayLike
V8_WARN_UNUSED_RESULT static MaybeHandle<FixedArray> CreateListFromArrayLike(
Isolate* isolate, Handle<Object> object, ElementTypes element_types);
// Get length property and apply ToLength.
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> GetLengthFromArrayLike(
Isolate* isolate, Handle<JSReceiver> object);
// ES6 section 12.5.6 The typeof Operator
static Handle<String> TypeOf(Isolate* isolate, Handle<Object> object);
// ES6 section 12.7 Additive Operators
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> Add(Isolate* isolate,
Handle<Object> lhs,
Handle<Object> rhs);
// ES6 section 12.9 Relational Operators
V8_WARN_UNUSED_RESULT static inline Maybe<bool> GreaterThan(Isolate* isolate,
Handle<Object> x,
Handle<Object> y);
V8_WARN_UNUSED_RESULT static inline Maybe<bool> GreaterThanOrEqual(
Isolate* isolate, Handle<Object> x, Handle<Object> y);
V8_WARN_UNUSED_RESULT static inline Maybe<bool> LessThan(Isolate* isolate,
Handle<Object> x,
Handle<Object> y);
V8_WARN_UNUSED_RESULT static inline Maybe<bool> LessThanOrEqual(
Isolate* isolate, Handle<Object> x, Handle<Object> y);
// ES6 section 7.3.19 OrdinaryHasInstance (C, O).
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> OrdinaryHasInstance(
Isolate* isolate, Handle<Object> callable, Handle<Object> object);
// ES6 section 12.10.4 Runtime Semantics: InstanceofOperator(O, C)
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> InstanceOf(
Isolate* isolate, Handle<Object> object, Handle<Object> callable);
V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static MaybeHandle<Object>
GetProperty(LookupIterator* it,
OnNonExistent on_non_existent = OnNonExistent::kReturnUndefined);
// ES6 [[Set]] (when passed kDontThrow)
// Invariants for this and related functions (unless stated otherwise):
// 1) When the result is Nothing, an exception is pending.
// 2) When passed kThrowOnError, 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).
V8_WARN_UNUSED_RESULT static Maybe<bool> SetProperty(
LookupIterator* it, Handle<Object> value, StoreOrigin store_origin,
Maybe<ShouldThrow> should_throw = Nothing<ShouldThrow>());
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> SetProperty(
Isolate* isolate, Handle<Object> object, Handle<Name> name,
Handle<Object> value, StoreOrigin store_origin = StoreOrigin::kMaybeKeyed,
Maybe<ShouldThrow> should_throw = Nothing<ShouldThrow>());
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> SetPropertyOrElement(
Isolate* isolate, Handle<Object> object, Handle<Name> name,
Handle<Object> value,
Maybe<ShouldThrow> should_throw = Nothing<ShouldThrow>(),
StoreOrigin store_origin = StoreOrigin::kMaybeKeyed);
V8_WARN_UNUSED_RESULT static Maybe<bool> SetSuperProperty(
LookupIterator* it, Handle<Object> value, StoreOrigin store_origin,
Maybe<ShouldThrow> should_throw = Nothing<ShouldThrow>());
V8_WARN_UNUSED_RESULT static Maybe<bool> CannotCreateProperty(
Isolate* isolate, Handle<Object> receiver, Handle<Object> name,
Handle<Object> value, Maybe<ShouldThrow> should_throw);
V8_WARN_UNUSED_RESULT static Maybe<bool> WriteToReadOnlyProperty(
LookupIterator* it, Handle<Object> value,
Maybe<ShouldThrow> should_throw);
V8_WARN_UNUSED_RESULT static Maybe<bool> WriteToReadOnlyProperty(
Isolate* isolate, Handle<Object> receiver, Handle<Object> name,
Handle<Object> value, ShouldThrow should_throw);
V8_WARN_UNUSED_RESULT static Maybe<bool> RedefineIncompatibleProperty(
Isolate* isolate, Handle<Object> name, Handle<Object> value,
Maybe<ShouldThrow> should_throw);
V8_WARN_UNUSED_RESULT static Maybe<bool> SetDataProperty(
LookupIterator* it, Handle<Object> value);
V8_WARN_UNUSED_RESULT static Maybe<bool> AddDataProperty(
LookupIterator* it, Handle<Object> value, PropertyAttributes attributes,
Maybe<ShouldThrow> should_throw, StoreOrigin store_origin);
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetPropertyOrElement(
Isolate* isolate, Handle<Object> object, Handle<Name> name);
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetPropertyOrElement(
Handle<Object> receiver, Handle<Name> name, Handle<JSReceiver> holder);
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetProperty(
Isolate* isolate, Handle<Object> object, Handle<Name> name);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> GetPropertyWithAccessor(
LookupIterator* it);
V8_WARN_UNUSED_RESULT static Maybe<bool> SetPropertyWithAccessor(
LookupIterator* it, Handle<Object> value,
Maybe<ShouldThrow> should_throw);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> GetPropertyWithDefinedGetter(
Handle<Object> receiver, Handle<JSReceiver> getter);
V8_WARN_UNUSED_RESULT static Maybe<bool> SetPropertyWithDefinedSetter(
Handle<Object> receiver, Handle<JSReceiver> setter, Handle<Object> value,
Maybe<ShouldThrow> should_throw);
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetElement(
Isolate* isolate, Handle<Object> object, uint32_t index);
V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> SetElement(
Isolate* isolate, Handle<Object> object, uint32_t index,
Handle<Object> value, ShouldThrow should_throw);
// Returns the permanent hash code associated with this object. May return
// undefined if not yet created.
inline 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.
Smi GetOrCreateHash(Isolate* isolate);
// 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 Object.is 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)
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ArraySpeciesConstructor(
Isolate* isolate, Handle<Object> original_array);
// ES6 section 7.3.20 SpeciesConstructor ( O, defaultConstructor )
V8_WARN_UNUSED_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) const;
// 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.
V8_WARN_UNUSED_RESULT inline bool ToArrayIndex(uint32_t* index) const;
// 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();
//
// The following GetHeapObjectXX methods mimic corresponding functionality
// in MaybeObject. Having them here allows us to unify code that processes
// ObjectSlots and MaybeObjectSlots.
//
// If this Object is a strong pointer to a HeapObject, returns true and
// sets *result. Otherwise returns false.
inline bool GetHeapObjectIfStrong(HeapObject* result) const;
// If this Object is a strong pointer to a HeapObject (weak pointers are not
// expected), returns true and sets *result. Otherwise returns false.
inline bool GetHeapObject(HeapObject* result) const;
// DCHECKs that this Object is a strong pointer to a HeapObject and returns
// the HeapObject.
inline HeapObject GetHeapObject() const;
// Always returns false because Object is not expected to be a weak pointer
// to a HeapObject.
inline bool GetHeapObjectIfWeak(HeapObject* result) const {
DCHECK(!HasWeakHeapObjectTag(ptr()));
return false;
}
// Always returns false because Object is not expected to be a weak pointer
// to a HeapObject.
inline bool IsCleared() const { return false; }
DECL_VERIFIER(Object)
#ifdef VERIFY_HEAP
// Verify a pointer is a valid object pointer.
static void VerifyPointer(Isolate* isolate, Object p);
#endif
inline void VerifyApiCallResultType();
// Prints this object without details.
void ShortPrint(FILE* out = stdout) const;
// Prints this object without details to a message accumulator.
void ShortPrint(StringStream* accumulator) const;
void ShortPrint(std::ostream& os) const; // NOLINT
DECL_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() const;
// Prints this object with details.
void Print(std::ostream& os) const; // NOLINT
#else
void Print() const { ShortPrint(); }
void Print(std::ostream& os) const { ShortPrint(os); } // NOLINT
#endif
// For use with std::unordered_set.
struct Hasher {
size_t operator()(const Object o) const {
return std::hash<v8::internal::Address>{}(o.ptr());
}
};
// For use with std::map.
struct Comparer {
bool operator()(const Object a, const Object b) const {
return a.ptr() < b.ptr();
}
};
private:
friend class CompressedObjectSlot;
friend class FullObjectSlot;
friend class LookupIterator;
friend class StringStream;
// Return the map of the root of object's prototype chain.
Map GetPrototypeChainRootMap(Isolate* isolate) const;
// Returns a non-SMI for JSReceivers, but returns the hash code for
// simple objects. This avoids a double lookup in the cases where
// we know we will add the hash to the JSReceiver if it does not
// already exist.
//
// Despite its size, this needs to be inlined for performance
// reasons.
static inline Object GetSimpleHash(Object object);
// Helper for SetProperty and SetSuperProperty.
// Return value is only meaningful if [found] is set to true on return.
V8_WARN_UNUSED_RESULT static Maybe<bool> SetPropertyInternal(
LookupIterator* it, Handle<Object> value, Maybe<ShouldThrow> should_throw,
StoreOrigin store_origin, bool* found);
V8_WARN_UNUSED_RESULT static MaybeHandle<Name> ConvertToName(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToPropertyKey(
Isolate* isolate, Handle<Object> value);
V8_WARN_UNUSED_RESULT static MaybeHandle<String> ConvertToString(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToNumberOrNumeric(
Isolate* isolate, Handle<Object> input, Conversion mode);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToInteger(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToInt32(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToUint32(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToLength(
Isolate* isolate, Handle<Object> input);
V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ConvertToIndex(
Isolate* isolate, Handle<Object> input, MessageTemplate error_index);
Address ptr_;
};
V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os, const Object& obj);
// In objects.h to be usable without objects-inl.h inclusion.
bool Object::IsSmi() const { return HAS_SMI_TAG(ptr()); }
bool Object::IsHeapObject() const {
DCHECK_EQ(!IsSmi(), Internals::HasHeapObjectTag(ptr()));
return !IsSmi();
}
struct Brief {
V8_EXPORT_PRIVATE explicit Brief(const Object v);
explicit Brief(const MaybeObject v);
// {value} is a tagged heap object reference (weak or strong), equivalent to
// a MaybeObject's payload. It has a plain Address type to keep #includes
// lightweight.
const Address value;
};
V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os, const Brief& v);
// Objects should never have the weak tag; this variant is for overzealous
// checking.
V8_INLINE static bool HasWeakHeapObjectTag(const Object value) {
return ((value->ptr() & kHeapObjectTagMask) == kWeakHeapObjectTag);
}
// 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 {
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() const;
// 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(Address value) : value_(value) {}
Address value_;
};
template <int start_offset, int end_offset, int size>
class FixedBodyDescriptor;
template <int start_offset>
class FlexibleBodyDescriptor;
template <int start_offset>
class FlexibleWeakBodyDescriptor;
template <class ParentBodyDescriptor, class ChildBodyDescriptor>
class SubclassBodyDescriptor;
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 = static_cast<int>(v8::KeyConversionMode::kKeepNumbers),
kConvertToString = static_cast<int>(v8::KeyConversionMode::kConvertToString)
};
enum class KeyCollectionMode {
kOwnOnly = static_cast<int>(v8::KeyCollectionMode::kOwnOnly),
kIncludePrototypes =
static_cast<int>(v8::KeyCollectionMode::kIncludePrototypes)
};
// Utility superclass for stack-allocated objects that must be updated
// on gc. It provides two ways for the gc to update instances, either
// iterating or updating after gc.
class Relocatable {
public:
explicit inline Relocatable(Isolate* isolate);
inline virtual ~Relocatable();
virtual void IterateInstance(RootVisitor* v) {}
virtual void PostGarbageCollection() { }
static void PostGarbageCollectionProcessing(Isolate* isolate);
static int ArchiveSpacePerThread();
static char* ArchiveState(Isolate* isolate, char* to);
static char* RestoreState(Isolate* isolate, char* from);
static void Iterate(Isolate* isolate, RootVisitor* v);
static void Iterate(RootVisitor* v, Relocatable* top);
static char* Iterate(RootVisitor* v, char* t);
private:
Isolate* isolate_;
Relocatable* prev_;
};
// BooleanBit is a helper class for setting and getting a bit in an integer.
class BooleanBit : public AllStatic {
public:
static inline bool get(int value, int bit_position) {
return (value & (1 << bit_position)) != 0;
}
static inline int set(int value, int bit_position, bool v) {
if (v) {
value |= (1 << bit_position);
} else {
value &= ~(1 << bit_position);
}
return value;
}
};
} // NOLINT, false-positive due to second-order macros.
} // NOLINT, false-positive due to second-order macros.
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_H_