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objects.h
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objects.h
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// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_OBJECTS_H_
#define V8_OBJECTS_H_
#include "allocation.h"
#include "builtins.h"
#include "list.h"
#include "property-details.h"
#include "smart-array-pointer.h"
#include "unicode-inl.h"
#if V8_TARGET_ARCH_ARM
#include "arm/constants-arm.h"
#elif V8_TARGET_ARCH_MIPS
#include "mips/constants-mips.h"
#endif
#include "v8checks.h"
//
// Most object types in the V8 JavaScript are described in this file.
//
// Inheritance hierarchy:
// - MaybeObject (an object or a failure)
// - Failure (immediate for marking failed operation)
// - Object
// - Smi (immediate small integer)
// - HeapObject (superclass for everything allocated in the heap)
// - JSReceiver (suitable for property access)
// - JSObject
// - JSArray
// - JSSet
// - JSMap
// - JSWeakMap
// - JSRegExp
// - JSFunction
// - GlobalObject
// - JSGlobalObject
// - JSBuiltinsObject
// - JSGlobalProxy
// - JSValue
// - JSMessageObject
// - JSProxy
// - JSFunctionProxy
// - FixedArrayBase
// - ByteArray
// - FixedArray
// - DescriptorArray
// - HashTable
// - Dictionary
// - SymbolTable
// - CompilationCacheTable
// - CodeCacheHashTable
// - MapCache
// - Context
// - JSFunctionResultCache
// - ScopeInfo
// - FixedDoubleArray
// - ExternalArray
// - ExternalPixelArray
// - ExternalByteArray
// - ExternalUnsignedByteArray
// - ExternalShortArray
// - ExternalUnsignedShortArray
// - ExternalIntArray
// - ExternalUnsignedIntArray
// - ExternalFloatArray
// - String
// - SeqString
// - SeqAsciiString
// - SeqTwoByteString
// - SlicedString
// - ConsString
// - ExternalString
// - ExternalAsciiString
// - ExternalTwoByteString
// - HeapNumber
// - Code
// - Map
// - Oddball
// - Foreign
// - SharedFunctionInfo
// - Struct
// - AccessorInfo
// - AccessorPair
// - AccessCheckInfo
// - InterceptorInfo
// - CallHandlerInfo
// - TemplateInfo
// - FunctionTemplateInfo
// - ObjectTemplateInfo
// - Script
// - SignatureInfo
// - TypeSwitchInfo
// - DebugInfo
// - BreakPointInfo
// - CodeCache
//
// Formats of Object*:
// Smi: [31 bit signed int] 0
// HeapObject: [32 bit direct pointer] (4 byte aligned) | 01
// Failure: [30 bit signed int] 11
namespace v8 {
namespace internal {
enum ElementsKind {
// The "fast" kind for elements that only contain SMI values. Must be first
// to make it possible to efficiently check maps for this kind.
FAST_SMI_ONLY_ELEMENTS,
// The "fast" kind for tagged values. Must be second to make it possible to
// efficiently check maps for this and the FAST_SMI_ONLY_ELEMENTS kind
// together at once.
FAST_ELEMENTS,
// The "fast" kind for unwrapped, non-tagged double values.
FAST_DOUBLE_ELEMENTS,
// The "slow" kind.
DICTIONARY_ELEMENTS,
NON_STRICT_ARGUMENTS_ELEMENTS,
// The "fast" kind for external arrays
EXTERNAL_BYTE_ELEMENTS,
EXTERNAL_UNSIGNED_BYTE_ELEMENTS,
EXTERNAL_SHORT_ELEMENTS,
EXTERNAL_UNSIGNED_SHORT_ELEMENTS,
EXTERNAL_INT_ELEMENTS,
EXTERNAL_UNSIGNED_INT_ELEMENTS,
EXTERNAL_FLOAT_ELEMENTS,
EXTERNAL_DOUBLE_ELEMENTS,
EXTERNAL_PIXEL_ELEMENTS,
// Derived constants from ElementsKind
FIRST_EXTERNAL_ARRAY_ELEMENTS_KIND = EXTERNAL_BYTE_ELEMENTS,
LAST_EXTERNAL_ARRAY_ELEMENTS_KIND = EXTERNAL_PIXEL_ELEMENTS,
FIRST_ELEMENTS_KIND = FAST_SMI_ONLY_ELEMENTS,
LAST_ELEMENTS_KIND = EXTERNAL_PIXEL_ELEMENTS
};
enum CompareMapMode {
REQUIRE_EXACT_MAP,
ALLOW_ELEMENT_TRANSITION_MAPS
};
const int kElementsKindCount = LAST_ELEMENTS_KIND - FIRST_ELEMENTS_KIND + 1;
void PrintElementsKind(FILE* out, ElementsKind kind);
inline bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind,
ElementsKind to_kind);
// Setter that skips the write barrier if mode is SKIP_WRITE_BARRIER.
enum WriteBarrierMode { SKIP_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
};
// NormalizedMapSharingMode is used to specify whether a map may be shared
// by different objects with normalized properties.
enum NormalizedMapSharingMode {
UNIQUE_NORMALIZED_MAP,
SHARED_NORMALIZED_MAP
};
// Indicates whether a get method should implicitly create the object looked up.
enum CreationFlag {
ALLOW_CREATION,
OMIT_CREATION
};
// Instance size sentinel for objects of variable size.
const int kVariableSizeSentinel = 0;
// 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. ASCII
// 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 SYMBOL_TYPE (if it is a
// symbol) or a STRING_TYPE (if it is not a symbol).
//
// 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_ALL(V) \
V(SYMBOL_TYPE) \
V(ASCII_SYMBOL_TYPE) \
V(CONS_SYMBOL_TYPE) \
V(CONS_ASCII_SYMBOL_TYPE) \
V(EXTERNAL_SYMBOL_TYPE) \
V(EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE) \
V(EXTERNAL_ASCII_SYMBOL_TYPE) \
V(SHORT_EXTERNAL_SYMBOL_TYPE) \
V(SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE) \
V(SHORT_EXTERNAL_ASCII_SYMBOL_TYPE) \
V(STRING_TYPE) \
V(ASCII_STRING_TYPE) \
V(CONS_STRING_TYPE) \
V(CONS_ASCII_STRING_TYPE) \
V(SLICED_STRING_TYPE) \
V(EXTERNAL_STRING_TYPE) \
V(EXTERNAL_STRING_WITH_ASCII_DATA_TYPE) \
V(EXTERNAL_ASCII_STRING_TYPE) \
V(SHORT_EXTERNAL_STRING_TYPE) \
V(SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE) \
V(SHORT_EXTERNAL_ASCII_STRING_TYPE) \
V(PRIVATE_EXTERNAL_ASCII_STRING_TYPE) \
\
V(MAP_TYPE) \
V(CODE_TYPE) \
V(ODDBALL_TYPE) \
V(JS_GLOBAL_PROPERTY_CELL_TYPE) \
\
V(HEAP_NUMBER_TYPE) \
V(FOREIGN_TYPE) \
V(BYTE_ARRAY_TYPE) \
V(FREE_SPACE_TYPE) \
/* Note: the order of these external array */ \
/* types is relied upon in */ \
/* Object::IsExternalArray(). */ \
V(EXTERNAL_BYTE_ARRAY_TYPE) \
V(EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE) \
V(EXTERNAL_SHORT_ARRAY_TYPE) \
V(EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE) \
V(EXTERNAL_INT_ARRAY_TYPE) \
V(EXTERNAL_UNSIGNED_INT_ARRAY_TYPE) \
V(EXTERNAL_FLOAT_ARRAY_TYPE) \
V(EXTERNAL_PIXEL_ARRAY_TYPE) \
V(FILLER_TYPE) \
\
V(ACCESSOR_INFO_TYPE) \
V(ACCESSOR_PAIR_TYPE) \
V(ACCESS_CHECK_INFO_TYPE) \
V(INTERCEPTOR_INFO_TYPE) \
V(CALL_HANDLER_INFO_TYPE) \
V(FUNCTION_TEMPLATE_INFO_TYPE) \
V(OBJECT_TEMPLATE_INFO_TYPE) \
V(SIGNATURE_INFO_TYPE) \
V(TYPE_SWITCH_INFO_TYPE) \
V(SCRIPT_TYPE) \
V(CODE_CACHE_TYPE) \
V(POLYMORPHIC_CODE_CACHE_TYPE) \
\
V(FIXED_ARRAY_TYPE) \
V(FIXED_DOUBLE_ARRAY_TYPE) \
V(SHARED_FUNCTION_INFO_TYPE) \
\
V(JS_MESSAGE_OBJECT_TYPE) \
\
V(JS_VALUE_TYPE) \
V(JS_OBJECT_TYPE) \
V(JS_CONTEXT_EXTENSION_OBJECT_TYPE) \
V(JS_GLOBAL_OBJECT_TYPE) \
V(JS_BUILTINS_OBJECT_TYPE) \
V(JS_GLOBAL_PROXY_TYPE) \
V(JS_ARRAY_TYPE) \
V(JS_PROXY_TYPE) \
V(JS_WEAK_MAP_TYPE) \
V(JS_REGEXP_TYPE) \
\
V(JS_FUNCTION_TYPE) \
V(JS_FUNCTION_PROXY_TYPE) \
#ifdef ENABLE_DEBUGGER_SUPPORT
#define INSTANCE_TYPE_LIST_DEBUGGER(V) \
V(DEBUG_INFO_TYPE) \
V(BREAK_POINT_INFO_TYPE)
#else
#define INSTANCE_TYPE_LIST_DEBUGGER(V)
#endif
#define INSTANCE_TYPE_LIST(V) \
INSTANCE_TYPE_LIST_ALL(V) \
INSTANCE_TYPE_LIST_DEBUGGER(V)
// Since string types are not consecutive, this macro is used to
// iterate over them.
#define STRING_TYPE_LIST(V) \
V(SYMBOL_TYPE, \
kVariableSizeSentinel, \
symbol, \
Symbol) \
V(ASCII_SYMBOL_TYPE, \
kVariableSizeSentinel, \
ascii_symbol, \
AsciiSymbol) \
V(CONS_SYMBOL_TYPE, \
ConsString::kSize, \
cons_symbol, \
ConsSymbol) \
V(CONS_ASCII_SYMBOL_TYPE, \
ConsString::kSize, \
cons_ascii_symbol, \
ConsAsciiSymbol) \
V(EXTERNAL_SYMBOL_TYPE, \
ExternalTwoByteString::kSize, \
external_symbol, \
ExternalSymbol) \
V(EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE, \
ExternalTwoByteString::kSize, \
external_symbol_with_ascii_data, \
ExternalSymbolWithAsciiData) \
V(EXTERNAL_ASCII_SYMBOL_TYPE, \
ExternalAsciiString::kSize, \
external_ascii_symbol, \
ExternalAsciiSymbol) \
V(SHORT_EXTERNAL_SYMBOL_TYPE, \
ExternalTwoByteString::kShortSize, \
short_external_symbol, \
ShortExternalSymbol) \
V(SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE, \
ExternalTwoByteString::kShortSize, \
short_external_symbol_with_ascii_data, \
ShortExternalSymbolWithAsciiData) \
V(SHORT_EXTERNAL_ASCII_SYMBOL_TYPE, \
ExternalAsciiString::kShortSize, \
short_external_ascii_symbol, \
ShortExternalAsciiSymbol) \
V(STRING_TYPE, \
kVariableSizeSentinel, \
string, \
String) \
V(ASCII_STRING_TYPE, \
kVariableSizeSentinel, \
ascii_string, \
AsciiString) \
V(CONS_STRING_TYPE, \
ConsString::kSize, \
cons_string, \
ConsString) \
V(CONS_ASCII_STRING_TYPE, \
ConsString::kSize, \
cons_ascii_string, \
ConsAsciiString) \
V(SLICED_STRING_TYPE, \
SlicedString::kSize, \
sliced_string, \
SlicedString) \
V(SLICED_ASCII_STRING_TYPE, \
SlicedString::kSize, \
sliced_ascii_string, \
SlicedAsciiString) \
V(EXTERNAL_STRING_TYPE, \
ExternalTwoByteString::kSize, \
external_string, \
ExternalString) \
V(EXTERNAL_STRING_WITH_ASCII_DATA_TYPE, \
ExternalTwoByteString::kSize, \
external_string_with_ascii_data, \
ExternalStringWithAsciiData) \
V(EXTERNAL_ASCII_STRING_TYPE, \
ExternalAsciiString::kSize, \
external_ascii_string, \
ExternalAsciiString) \
V(SHORT_EXTERNAL_STRING_TYPE, \
ExternalTwoByteString::kShortSize, \
short_external_string, \
ShortExternalString) \
V(SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE, \
ExternalTwoByteString::kShortSize, \
short_external_string_with_ascii_data, \
ShortExternalStringWithAsciiData) \
V(SHORT_EXTERNAL_ASCII_STRING_TYPE, \
ExternalAsciiString::kShortSize, \
short_external_ascii_string, \
ShortExternalAsciiString)
// 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_ALL(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(CALL_HANDLER_INFO, CallHandlerInfo, call_handler_info) \
V(FUNCTION_TEMPLATE_INFO, FunctionTemplateInfo, function_template_info) \
V(OBJECT_TEMPLATE_INFO, ObjectTemplateInfo, object_template_info) \
V(SIGNATURE_INFO, SignatureInfo, signature_info) \
V(TYPE_SWITCH_INFO, TypeSwitchInfo, type_switch_info) \
V(SCRIPT, Script, script) \
V(CODE_CACHE, CodeCache, code_cache) \
V(POLYMORPHIC_CODE_CACHE, PolymorphicCodeCache, polymorphic_code_cache)
#ifdef ENABLE_DEBUGGER_SUPPORT
#define STRUCT_LIST_DEBUGGER(V) \
V(DEBUG_INFO, DebugInfo, debug_info) \
V(BREAK_POINT_INFO, BreakPointInfo, break_point_info)
#else
#define STRUCT_LIST_DEBUGGER(V)
#endif
#define STRUCT_LIST(V) \
STRUCT_LIST_ALL(V) \
STRUCT_LIST_DEBUGGER(V)
// 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 a symbol (if set) or not (if cleared).
// There are not enough types that the non-string types (with bit 7 set) can
// have bit 6 set too.
const uint32_t kIsSymbolMask = 0x40;
const uint32_t kNotSymbolTag = 0x0;
const uint32_t kSymbolTag = 0x40;
// If bit 7 is clear then bit 2 indicates whether the string consists of
// two-byte characters or one-byte characters.
const uint32_t kStringEncodingMask = 0x4;
const uint32_t kTwoByteStringTag = 0x0;
const uint32_t kAsciiStringTag = 0x4;
// If bit 7 is clear, the low-order 2 bits indicate the representation
// of the string.
const uint32_t kStringRepresentationMask = 0x03;
enum StringRepresentationTag {
kSeqStringTag = 0x0,
kConsStringTag = 0x1,
kExternalStringTag = 0x2,
kSlicedStringTag = 0x3
};
const uint32_t kIsIndirectStringMask = 0x1;
const uint32_t kIsIndirectStringTag = 0x1;
STATIC_ASSERT((kSeqStringTag & kIsIndirectStringMask) == 0);
STATIC_ASSERT((kExternalStringTag & kIsIndirectStringMask) == 0);
STATIC_ASSERT(
(kConsStringTag & kIsIndirectStringMask) == kIsIndirectStringTag);
STATIC_ASSERT(
(kSlicedStringTag & kIsIndirectStringMask) == kIsIndirectStringTag);
// Use this mask to distinguish between cons and slice only after making
// sure that the string is one of the two (an indirect string).
const uint32_t kSlicedNotConsMask = kSlicedStringTag & ~kConsStringTag;
STATIC_ASSERT(IS_POWER_OF_TWO(kSlicedNotConsMask) && kSlicedNotConsMask != 0);
// If bit 7 is clear, then bit 3 indicates whether this two-byte
// string actually contains ASCII data.
const uint32_t kAsciiDataHintMask = 0x08;
const uint32_t kAsciiDataHintTag = 0x08;
// If bit 7 is clear and string representation indicates an external string,
// then bit 4 indicates whether the data pointer is cached.
const uint32_t kShortExternalStringMask = 0x10;
const uint32_t kShortExternalStringTag = 0x10;
// A ConsString with an empty string as the right side is a candidate
// for being shortcut by the garbage collector unless it is a
// symbol. It's not common to have non-flat symbols, so we do not
// shortcut them thereby avoiding turning symbols into strings. See
// heap.cc and mark-compact.cc.
const uint32_t kShortcutTypeMask =
kIsNotStringMask |
kIsSymbolMask |
kStringRepresentationMask;
const uint32_t kShortcutTypeTag = kConsStringTag;
enum InstanceType {
// String types.
SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kSeqStringTag,
ASCII_SYMBOL_TYPE = kAsciiStringTag | kSymbolTag | kSeqStringTag,
CONS_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kConsStringTag,
CONS_ASCII_SYMBOL_TYPE = kAsciiStringTag | kSymbolTag | kConsStringTag,
SHORT_EXTERNAL_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag |
kExternalStringTag | kShortExternalStringTag,
SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE =
kTwoByteStringTag | kSymbolTag | kExternalStringTag |
kAsciiDataHintTag | kShortExternalStringTag,
SHORT_EXTERNAL_ASCII_SYMBOL_TYPE = kAsciiStringTag | kExternalStringTag |
kSymbolTag | kShortExternalStringTag,
EXTERNAL_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kExternalStringTag,
EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE =
kTwoByteStringTag | kSymbolTag | kExternalStringTag | kAsciiDataHintTag,
EXTERNAL_ASCII_SYMBOL_TYPE =
kAsciiStringTag | kSymbolTag | kExternalStringTag,
STRING_TYPE = kTwoByteStringTag | kSeqStringTag,
ASCII_STRING_TYPE = kAsciiStringTag | kSeqStringTag,
CONS_STRING_TYPE = kTwoByteStringTag | kConsStringTag,
CONS_ASCII_STRING_TYPE = kAsciiStringTag | kConsStringTag,
SLICED_STRING_TYPE = kTwoByteStringTag | kSlicedStringTag,
SLICED_ASCII_STRING_TYPE = kAsciiStringTag | kSlicedStringTag,
SHORT_EXTERNAL_STRING_TYPE =
kTwoByteStringTag | kExternalStringTag | kShortExternalStringTag,
SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =
kTwoByteStringTag | kExternalStringTag |
kAsciiDataHintTag | kShortExternalStringTag,
SHORT_EXTERNAL_ASCII_STRING_TYPE =
kAsciiStringTag | kExternalStringTag | kShortExternalStringTag,
EXTERNAL_STRING_TYPE = kTwoByteStringTag | kExternalStringTag,
EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =
kTwoByteStringTag | kExternalStringTag | kAsciiDataHintTag,
// LAST_STRING_TYPE
EXTERNAL_ASCII_STRING_TYPE = kAsciiStringTag | kExternalStringTag,
PRIVATE_EXTERNAL_ASCII_STRING_TYPE = EXTERNAL_ASCII_STRING_TYPE,
// Objects allocated in their own spaces (never in new space).
MAP_TYPE = kNotStringTag, // FIRST_NONSTRING_TYPE
CODE_TYPE,
ODDBALL_TYPE,
JS_GLOBAL_PROPERTY_CELL_TYPE,
// "Data", objects that cannot contain non-map-word pointers to heap
// objects.
HEAP_NUMBER_TYPE,
FOREIGN_TYPE,
BYTE_ARRAY_TYPE,
FREE_SPACE_TYPE,
EXTERNAL_BYTE_ARRAY_TYPE, // FIRST_EXTERNAL_ARRAY_TYPE
EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE,
EXTERNAL_SHORT_ARRAY_TYPE,
EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE,
EXTERNAL_INT_ARRAY_TYPE,
EXTERNAL_UNSIGNED_INT_ARRAY_TYPE,
EXTERNAL_FLOAT_ARRAY_TYPE,
EXTERNAL_DOUBLE_ARRAY_TYPE,
EXTERNAL_PIXEL_ARRAY_TYPE, // LAST_EXTERNAL_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,
CALL_HANDLER_INFO_TYPE,
FUNCTION_TEMPLATE_INFO_TYPE,
OBJECT_TEMPLATE_INFO_TYPE,
SIGNATURE_INFO_TYPE,
TYPE_SWITCH_INFO_TYPE,
SCRIPT_TYPE,
CODE_CACHE_TYPE,
POLYMORPHIC_CODE_CACHE_TYPE,
// The following two instance types are only used when ENABLE_DEBUGGER_SUPPORT
// is defined. However as include/v8.h contain some of the instance type
// constants always having them avoids them getting different numbers
// depending on whether ENABLE_DEBUGGER_SUPPORT is defined or not.
DEBUG_INFO_TYPE,
BREAK_POINT_INFO_TYPE,
FIXED_ARRAY_TYPE,
SHARED_FUNCTION_INFO_TYPE,
JS_MESSAGE_OBJECT_TYPE,
// 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/SPEC_OBJECT range and the
// NONCALLABLE_JS_OBJECT range.
JS_FUNCTION_PROXY_TYPE, // FIRST_JS_RECEIVER_TYPE, FIRST_JS_PROXY_TYPE
JS_PROXY_TYPE, // LAST_JS_PROXY_TYPE
JS_VALUE_TYPE, // FIRST_JS_OBJECT_TYPE
JS_OBJECT_TYPE,
JS_CONTEXT_EXTENSION_OBJECT_TYPE,
JS_GLOBAL_OBJECT_TYPE,
JS_BUILTINS_OBJECT_TYPE,
JS_GLOBAL_PROXY_TYPE,
JS_ARRAY_TYPE,
JS_SET_TYPE,
JS_MAP_TYPE,
JS_WEAK_MAP_TYPE,
JS_REGEXP_TYPE,
JS_FUNCTION_TYPE, // LAST_JS_OBJECT_TYPE, LAST_JS_RECEIVER_TYPE
// Pseudo-types
FIRST_TYPE = 0x0,
LAST_TYPE = JS_FUNCTION_TYPE,
INVALID_TYPE = FIRST_TYPE - 1,
FIRST_NONSTRING_TYPE = MAP_TYPE,
// Boundaries for testing for an external array.
FIRST_EXTERNAL_ARRAY_TYPE = EXTERNAL_BYTE_ARRAY_TYPE,
LAST_EXTERNAL_ARRAY_TYPE = EXTERNAL_PIXEL_ARRAY_TYPE,
// Boundary for promotion to old data space/old pointer 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_FUNCTION_PROXY_TYPE,
LAST_JS_RECEIVER_TYPE = LAST_TYPE,
// Boundaries for testing the types represented as JSObject
FIRST_JS_OBJECT_TYPE = JS_VALUE_TYPE,
LAST_JS_OBJECT_TYPE = LAST_TYPE,
// Boundaries for testing the types represented as JSProxy
FIRST_JS_PROXY_TYPE = JS_FUNCTION_PROXY_TYPE,
LAST_JS_PROXY_TYPE = JS_PROXY_TYPE,
// Boundaries for testing whether the type is a JavaScript object.
FIRST_SPEC_OBJECT_TYPE = FIRST_JS_RECEIVER_TYPE,
LAST_SPEC_OBJECT_TYPE = LAST_JS_RECEIVER_TYPE,
// Boundaries for testing the types for which typeof is "object".
FIRST_NONCALLABLE_SPEC_OBJECT_TYPE = JS_PROXY_TYPE,
LAST_NONCALLABLE_SPEC_OBJECT_TYPE = JS_REGEXP_TYPE,
// Note that the types for which typeof is "function" are not continuous.
// Define this so that we can put assertions on discrete checks.
NUM_OF_CALLABLE_SPEC_OBJECT_TYPES = 2
};
const int kExternalArrayTypeCount =
LAST_EXTERNAL_ARRAY_TYPE - FIRST_EXTERNAL_ARRAY_TYPE + 1;
STATIC_CHECK(JS_OBJECT_TYPE == Internals::kJSObjectType);
STATIC_CHECK(FIRST_NONSTRING_TYPE == Internals::kFirstNonstringType);
STATIC_CHECK(FOREIGN_TYPE == Internals::kForeignType);
enum CompareResult {
LESS = -1,
EQUAL = 0,
GREATER = 1,
NOT_EQUAL = GREATER
};
#define DECL_BOOLEAN_ACCESSORS(name) \
inline bool name(); \
inline void set_##name(bool value); \
#define DECL_ACCESSORS(name, type) \
inline type* name(); \
inline void set_##name(type* value, \
WriteBarrierMode mode = UPDATE_WRITE_BARRIER); \
class DictionaryElementsAccessor;
class ElementsAccessor;
class FixedArrayBase;
class ObjectVisitor;
class StringStream;
class Failure;
struct ValueInfo : public Malloced {
ValueInfo() : type(FIRST_TYPE), ptr(NULL), str(NULL), number(0) { }
InstanceType type;
Object* ptr;
const char* str;
double number;
};
// A template-ized version of the IsXXX functions.
template <class C> static inline bool Is(Object* obj);
class MaybeObject BASE_EMBEDDED {
public:
inline bool IsFailure();
inline bool IsRetryAfterGC();
inline bool IsOutOfMemory();
inline bool IsException();
INLINE(bool IsTheHole());
inline bool ToObject(Object** obj) {
if (IsFailure()) return false;
*obj = reinterpret_cast<Object*>(this);
return true;
}
inline Failure* ToFailureUnchecked() {
ASSERT(IsFailure());
return reinterpret_cast<Failure*>(this);
}
inline Object* ToObjectUnchecked() {
ASSERT(!IsFailure());
return reinterpret_cast<Object*>(this);
}
inline Object* ToObjectChecked() {
CHECK(!IsFailure());
return reinterpret_cast<Object*>(this);
}
template<typename T>
inline bool To(T** obj) {
if (IsFailure()) return false;
*obj = T::cast(reinterpret_cast<Object*>(this));
return true;
}
#ifdef OBJECT_PRINT
// Prints this object with details.
inline void Print() {
Print(stdout);
}
inline void PrintLn() {
PrintLn(stdout);
}
void Print(FILE* out);
void PrintLn(FILE* out);
#endif
#ifdef DEBUG
// Verifies the object.
void Verify();
#endif
};
#define OBJECT_TYPE_LIST(V) \
V(Smi) \
V(HeapObject) \
V(Number) \
#define HEAP_OBJECT_TYPE_LIST(V) \
V(HeapNumber) \
V(String) \
V(Symbol) \
V(SeqString) \
V(ExternalString) \
V(ConsString) \
V(SlicedString) \
V(ExternalTwoByteString) \
V(ExternalAsciiString) \
V(SeqTwoByteString) \
V(SeqAsciiString) \
\
V(ExternalArray) \
V(ExternalByteArray) \
V(ExternalUnsignedByteArray) \
V(ExternalShortArray) \
V(ExternalUnsignedShortArray) \
V(ExternalIntArray) \
V(ExternalUnsignedIntArray) \
V(ExternalFloatArray) \
V(ExternalDoubleArray) \
V(ExternalPixelArray) \
V(ByteArray) \
V(FreeSpace) \
V(JSReceiver) \
V(JSObject) \
V(JSContextExtensionObject) \
V(Map) \
V(DescriptorArray) \
V(DeoptimizationInputData) \
V(DeoptimizationOutputData) \
V(TypeFeedbackCells) \
V(FixedArray) \
V(FixedDoubleArray) \
V(Context) \
V(GlobalContext) \
V(ScopeInfo) \
V(JSFunction) \
V(Code) \
V(Oddball) \
V(SharedFunctionInfo) \
V(JSValue) \
V(JSMessageObject) \
V(StringWrapper) \
V(Foreign) \
V(Boolean) \
V(JSArray) \
V(JSProxy) \
V(JSFunctionProxy) \
V(JSSet) \
V(JSMap) \
V(JSWeakMap) \
V(JSRegExp) \
V(HashTable) \
V(Dictionary) \
V(SymbolTable) \
V(JSFunctionResultCache) \
V(NormalizedMapCache) \
V(CompilationCacheTable) \
V(CodeCacheHashTable) \
V(PolymorphicCodeCacheHashTable) \
V(MapCache) \
V(Primitive) \
V(GlobalObject) \
V(JSGlobalObject) \
V(JSBuiltinsObject) \
V(JSGlobalProxy) \
V(UndetectableObject) \
V(AccessCheckNeeded) \
V(JSGlobalPropertyCell) \
class JSReceiver;
// 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 Smi and Failure are subclasses of Object no
// data members can be present in Object.
class Object : public MaybeObject {
public:
// Type testing.
#define IS_TYPE_FUNCTION_DECL(type_) inline bool Is##type_();
OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
HEAP_OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
#undef IS_TYPE_FUNCTION_DECL
inline bool IsFixedArrayBase();
// Returns true if this object is an instance of the specified
// function template.
inline bool IsInstanceOf(FunctionTemplateInfo* type);
inline bool IsStruct();
#define DECLARE_STRUCT_PREDICATE(NAME, Name, name) inline bool Is##Name();
STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
#undef DECLARE_STRUCT_PREDICATE
INLINE(bool IsSpecObject());
INLINE(bool IsSpecFunction());
// Oddball testing.
INLINE(bool IsUndefined());
INLINE(bool IsNull());
INLINE(bool IsTheHole()); // Shadows MaybeObject's implementation.
INLINE(bool IsTrue());
INLINE(bool IsFalse());
inline bool IsArgumentsMarker();
inline bool NonFailureIsHeapObject();
// Filler objects (fillers and free space objects).
inline bool IsFiller();
// Extract the number.
inline double Number();
// 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);
MUST_USE_RESULT MaybeObject* ToObject(); // ECMA-262 9.9.
Object* ToBoolean(); // ECMA-262 9.2.
// Convert to a JSObject if needed.
// global_context is used when creating wrapper object.
MUST_USE_RESULT MaybeObject* ToObject(Context* global_context);
// Converts this to a Smi if possible.
// Failure is returned otherwise.
MUST_USE_RESULT inline MaybeObject* ToSmi();
void Lookup(String* name, LookupResult* result);
// Property access.
MUST_USE_RESULT inline MaybeObject* GetProperty(String* key);
MUST_USE_RESULT inline MaybeObject* GetProperty(
String* key,
PropertyAttributes* attributes);
MUST_USE_RESULT MaybeObject* GetPropertyWithReceiver(
Object* receiver,
String* key,
PropertyAttributes* attributes);
static Handle<Object> GetProperty(Handle<Object> object,
Handle<Object> receiver,
LookupResult* result,
Handle<String> key,
PropertyAttributes* attributes);
MUST_USE_RESULT MaybeObject* GetProperty(Object* receiver,
LookupResult* result,
String* key,
PropertyAttributes* attributes);
MUST_USE_RESULT MaybeObject* GetPropertyWithDefinedGetter(Object* receiver,
JSReceiver* getter);
static Handle<Object> GetElement(Handle<Object> object, uint32_t index);
inline MaybeObject* GetElement(uint32_t index);
// For use when we know that no exception can be thrown.
inline Object* GetElementNoExceptionThrown(uint32_t index);
MaybeObject* GetElementWithReceiver(Object* receiver, uint32_t index);
// Return the object's prototype (might be Heap::null_value()).
Object* GetPrototype();
// Returns the permanent hash code associated with this object depending on
// the actual object type. Might return a failure in case no hash was
// created yet or GC was caused by creation.
MUST_USE_RESULT MaybeObject* GetHash(CreationFlag flag);
// 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.
bool SameValue(Object* other);
// Tries to convert an object to an array index. Returns true and sets
// the output parameter if it succeeds.
inline bool ToArrayIndex(uint32_t* index);
// Returns true if this is a JSValue containing a string and the index is
// < the length of the string. Used to implement [] on strings.
inline bool IsStringObjectWithCharacterAt(uint32_t index);
#ifdef DEBUG
// Verify a pointer is a valid object pointer.
static void VerifyPointer(Object* p);
#endif
// Prints this object without details.
inline void ShortPrint() {
ShortPrint(stdout);
}
void ShortPrint(FILE* out);
// Prints this object without details to a message accumulator.
void ShortPrint(StringStream* accumulator);
// Casting: This cast is only needed to satisfy macros in objects-inl.h.
static Object* cast(Object* value) { return value; }
// Layout description.
static const int kHeaderSize = 0; // Object does not take up any space.
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Object);
};
// 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();
// Convert a value to a Smi object.
static inline Smi* FromInt(int value);
static inline Smi* FromIntptr(intptr_t value);
// Returns whether value can be represented in a Smi.
static inline bool IsValid(intptr_t value);
// Casting.
static inline Smi* cast(Object* object);
// Dispatched behavior.
inline void SmiPrint() {