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ara-mdk / platform / external / v8 / 90bac256d9f48d4ee52d0e08bf0e5cad57b3c51c / . / src / objects.h
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// Copyright 2010 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 "builtins.h"
#include "smart-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
//
// 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)
// - JSObject
// - JSArray
// - JSRegExp
// - JSFunction
// - GlobalObject
// - JSGlobalObject
// - JSBuiltinsObject
// - JSGlobalProxy
// - JSValue
// - ByteArray
// - PixelArray
// - ExternalArray
// - ExternalByteArray
// - ExternalUnsignedByteArray
// - ExternalShortArray
// - ExternalUnsignedShortArray
// - ExternalIntArray
// - ExternalUnsignedIntArray
// - ExternalFloatArray
// - FixedArray
// - DescriptorArray
// - HashTable
// - Dictionary
// - SymbolTable
// - CompilationCacheTable
// - CodeCacheHashTable
// - MapCache
// - Context
// - JSFunctionResultCache
// - SerializedScopeInfo
// - String
// - SeqString
// - SeqAsciiString
// - SeqTwoByteString
// - ConsString
// - ExternalString
// - ExternalAsciiString
// - ExternalTwoByteString
// - HeapNumber
// - Code
// - Map
// - Oddball
// - Proxy
// - SharedFunctionInfo
// - Struct
// - AccessorInfo
// - 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
// Ecma-262 3rd 8.6.1
enum PropertyAttributes {
NONE = v8::None,
READ_ONLY = v8::ReadOnly,
DONT_ENUM = v8::DontEnum,
DONT_DELETE = v8::DontDelete,
ABSENT = 16 // Used in runtime to indicate a property is absent.
// ABSENT can never be stored in or returned from a descriptor's attributes
// bitfield. It is only used as a return value meaning the attributes of
// a non-existent property.
};
namespace v8 {
namespace internal {
// PropertyDetails captures type and attributes for a property.
// They are used both in property dictionaries and instance descriptors.
class PropertyDetails BASE_EMBEDDED {
public:
PropertyDetails(PropertyAttributes attributes,
PropertyType type,
int index = 0) {
ASSERT(TypeField::is_valid(type));
ASSERT(AttributesField::is_valid(attributes));
ASSERT(IndexField::is_valid(index));
value_ = TypeField::encode(type)
| AttributesField::encode(attributes)
| IndexField::encode(index);
ASSERT(type == this->type());
ASSERT(attributes == this->attributes());
ASSERT(index == this->index());
}
// Conversion for storing details as Object*.
inline PropertyDetails(Smi* smi);
inline Smi* AsSmi();
PropertyType type() { return TypeField::decode(value_); }
bool IsTransition() {
PropertyType t = type();
ASSERT(t != INTERCEPTOR);
return t == MAP_TRANSITION || t == CONSTANT_TRANSITION;
}
bool IsProperty() {
return type() < FIRST_PHANTOM_PROPERTY_TYPE;
}
PropertyAttributes attributes() { return AttributesField::decode(value_); }
int index() { return IndexField::decode(value_); }
inline PropertyDetails AsDeleted();
static bool IsValidIndex(int index) { return IndexField::is_valid(index); }
bool IsReadOnly() { return (attributes() & READ_ONLY) != 0; }
bool IsDontDelete() { return (attributes() & DONT_DELETE) != 0; }
bool IsDontEnum() { return (attributes() & DONT_ENUM) != 0; }
bool IsDeleted() { return DeletedField::decode(value_) != 0;}
// Bit fields in value_ (type, shift, size). Must be public so the
// constants can be embedded in generated code.
class TypeField: public BitField<PropertyType, 0, 3> {};
class AttributesField: public BitField<PropertyAttributes, 3, 3> {};
class DeletedField: public BitField<uint32_t, 6, 1> {};
class IndexField: public BitField<uint32_t, 7, 32-7> {};
static const int kInitialIndex = 1;
private:
uint32_t value_;
};
// 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
};
// Instance size sentinel for objects of variable size.
static 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 (eg, 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(STRING_TYPE) \
V(ASCII_STRING_TYPE) \
V(CONS_STRING_TYPE) \
V(CONS_ASCII_STRING_TYPE) \
V(EXTERNAL_STRING_TYPE) \
V(EXTERNAL_STRING_WITH_ASCII_DATA_TYPE) \
V(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(PROXY_TYPE) \
V(BYTE_ARRAY_TYPE) \
V(PIXEL_ARRAY_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(FILLER_TYPE) \
\
V(ACCESSOR_INFO_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(FIXED_ARRAY_TYPE) \
V(SHARED_FUNCTION_INFO_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_REGEXP_TYPE) \
\
V(JS_FUNCTION_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(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(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)
// 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(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)
#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
};
const uint32_t kIsConsStringMask = 0x1;
// 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;
// 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,
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,
EXTERNAL_STRING_TYPE = kTwoByteStringTag | kExternalStringTag,
EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =
kTwoByteStringTag | kExternalStringTag | kAsciiDataHintTag,
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,
PROXY_TYPE,
BYTE_ARRAY_TYPE,
PIXEL_ARRAY_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, // LAST_EXTERNAL_ARRAY_TYPE
FILLER_TYPE, // LAST_DATA_TYPE
// Structs.
ACCESSOR_INFO_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,
// 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_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_REGEXP_TYPE, // LAST_JS_OBJECT_TYPE
JS_FUNCTION_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_FLOAT_ARRAY_TYPE,
// Boundary for promotion to old data space/old pointer space.
LAST_DATA_TYPE = FILLER_TYPE,
// Boundaries for testing the type is a JavaScript "object". Note that
// function objects are not counted as objects, even though they are
// implemented as such; only values whose typeof is "object" are included.
FIRST_JS_OBJECT_TYPE = JS_VALUE_TYPE,
LAST_JS_OBJECT_TYPE = JS_REGEXP_TYPE
};
STATIC_CHECK(JS_OBJECT_TYPE == Internals::kJSObjectType);
STATIC_CHECK(FIRST_NONSTRING_TYPE == Internals::kFirstNonstringType);
STATIC_CHECK(PROXY_TYPE == Internals::kProxyType);
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 StringStream;
class ObjectVisitor;
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 Object* ToObjectUnchecked() {
ASSERT(!IsFailure());
return reinterpret_cast<Object*>(this);
}
inline Object* ToObjectChecked() {
CHECK(!IsFailure());
return reinterpret_cast<Object*>(this);
}
#ifdef DEBUG
// Prints this object with details.
void Print();
void PrintLn();
// Verifies the object.
void Verify();
#endif
};
// 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.
inline bool IsSmi();
inline bool IsHeapObject();
inline bool IsHeapNumber();
inline bool IsString();
inline bool IsSymbol();
// See objects-inl.h for more details
inline bool IsSeqString();
inline bool IsExternalString();
inline bool IsExternalTwoByteString();
inline bool IsExternalAsciiString();
inline bool IsSeqTwoByteString();
inline bool IsSeqAsciiString();
inline bool IsConsString();
inline bool IsNumber();
inline bool IsByteArray();
inline bool IsPixelArray();
inline bool IsExternalArray();
inline bool IsExternalByteArray();
inline bool IsExternalUnsignedByteArray();
inline bool IsExternalShortArray();
inline bool IsExternalUnsignedShortArray();
inline bool IsExternalIntArray();
inline bool IsExternalUnsignedIntArray();
inline bool IsExternalFloatArray();
inline bool IsJSObject();
inline bool IsJSContextExtensionObject();
inline bool IsMap();
inline bool IsFixedArray();
inline bool IsDescriptorArray();
inline bool IsContext();
inline bool IsCatchContext();
inline bool IsGlobalContext();
inline bool IsJSFunction();
inline bool IsCode();
inline bool IsOddball();
inline bool IsSharedFunctionInfo();
inline bool IsJSValue();
inline bool IsStringWrapper();
inline bool IsProxy();
inline bool IsBoolean();
inline bool IsJSArray();
inline bool IsJSRegExp();
inline bool IsHashTable();
inline bool IsDictionary();
inline bool IsSymbolTable();
inline bool IsJSFunctionResultCache();
inline bool IsNormalizedMapCache();
inline bool IsCompilationCacheTable();
inline bool IsCodeCacheHashTable();
inline bool IsMapCache();
inline bool IsPrimitive();
inline bool IsGlobalObject();
inline bool IsJSGlobalObject();
inline bool IsJSBuiltinsObject();
inline bool IsJSGlobalProxy();
inline bool IsUndetectableObject();
inline bool IsAccessCheckNeeded();
inline bool IsJSGlobalPropertyCell();
// 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
// Oddball testing.
INLINE(bool IsUndefined());
INLINE(bool IsNull());
INLINE(bool IsTrue());
INLINE(bool IsFalse());
// Extract the number.
inline double Number();
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);
MUST_USE_RESULT MaybeObject* GetProperty(Object* receiver,
LookupResult* result,
String* key,
PropertyAttributes* attributes);
MUST_USE_RESULT MaybeObject* GetPropertyWithCallback(Object* receiver,
Object* structure,
String* name,
Object* holder);
MUST_USE_RESULT MaybeObject* GetPropertyWithDefinedGetter(Object* receiver,
JSFunction* getter);
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();
// 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.
void ShortPrint();
// 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.
void SmiPrint();
void SmiPrint(StringStream* accumulator);
#ifdef DEBUG
void SmiVerify();
#endif
static const int kMinValue = (-1 << (kSmiValueSize - 1));
static const int kMaxValue = -(kMinValue + 1);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Smi);
};
// Failure is used for reporting out of memory situations and
// propagating exceptions through the runtime system. Failure objects
// are transient and cannot occur as part of the object graph.
//
// Failures are a single word, encoded as follows:
// +-------------------------+---+--+--+
// |.........unused..........|sss|tt|11|
// +-------------------------+---+--+--+
// 7 6 4 32 10
//
//
// The low two bits, 0-1, are the failure tag, 11. The next two bits,
// 2-3, are a failure type tag 'tt' with possible values:
// 00 RETRY_AFTER_GC
// 01 EXCEPTION
// 10 INTERNAL_ERROR
// 11 OUT_OF_MEMORY_EXCEPTION
//
// The next three bits, 4-6, are an allocation space tag 'sss'. The
// allocation space tag is 000 for all failure types except
// RETRY_AFTER_GC. For RETRY_AFTER_GC, the possible values are the
// allocation spaces (the encoding is found in globals.h).
// Failure type tag info.
const int kFailureTypeTagSize = 2;
const int kFailureTypeTagMask = (1 << kFailureTypeTagSize) - 1;
class Failure: public MaybeObject {
public:
// RuntimeStubs assumes EXCEPTION = 1 in the compiler-generated code.
enum Type {
RETRY_AFTER_GC = 0,
EXCEPTION = 1, // Returning this marker tells the real exception
// is in Top::pending_exception.
INTERNAL_ERROR = 2,
OUT_OF_MEMORY_EXCEPTION = 3
};
inline Type type() const;
// Returns the space that needs to be collected for RetryAfterGC failures.
inline AllocationSpace allocation_space() const;
inline bool IsInternalError() const;
inline bool IsOutOfMemoryException() const;
static inline Failure* RetryAfterGC(AllocationSpace space);
static inline Failure* RetryAfterGC(); // NEW_SPACE
static inline Failure* Exception();
static inline Failure* InternalError();
static inline Failure* OutOfMemoryException();
// Casting.
static inline Failure* cast(MaybeObject* object);
// Dispatched behavior.
void FailurePrint();
void FailurePrint(StringStream* accumulator);
#ifdef DEBUG
void FailureVerify();
#endif
private:
inline intptr_t value() const;
static inline Failure* Construct(Type type, intptr_t value = 0);
DISALLOW_IMPLICIT_CONSTRUCTORS(Failure);
};
// Heap objects typically have a map pointer in their first word. However,
// during GC other data (eg, 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(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, ie. not during a full GC).
inline bool IsForwardingAddress();
// 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();
// Marking phase of full collection: the map word of live objects is
// marked, and may be marked as overflowed (eg, the object is live, its
// children have not been visited, and it does not fit in the marking
// stack).
// True if this map word's mark bit is set.
inline bool IsMarked();
// Return this map word but with its mark bit set.
inline void SetMark();
// Return this map word but with its mark bit cleared.
inline void ClearMark();
// True if this map word's overflow bit is set.
inline bool IsOverflowed();
// Return this map word but with its overflow bit set.
inline void SetOverflow();
// Return this map word but with its overflow bit cleared.
inline void ClearOverflow();
// Compacting phase of a full compacting collection: the map word of live
// objects contains an encoding of the original map address along with the
// forwarding address (represented as an offset from the first live object
// in the same page as the (old) object address).
// Create a map word from a map address and a forwarding address offset.
static inline MapWord EncodeAddress(Address map_address, int offset);
// Return the map address encoded in this map word.
inline Address DecodeMapAddress(MapSpace* map_space);
// Return the forwarding offset encoded in this map word.
inline int DecodeOffset();
// During serialization: the map word is used to hold an encoded
// address, and possibly a mark bit (set and cleared with SetMark
// and ClearMark).
// Create a map word from an encoded address.
static inline MapWord FromEncodedAddress(Address address);
inline Address ToEncodedAddress();
// Bits used by the marking phase of the garbage collector.
//
// The first word of a heap object is normally a map pointer. The last two
// bits are tagged as '01' (kHeapObjectTag). We reuse the last two bits to
// mark an object as live and/or overflowed:
// last bit = 0, marked as alive
// second bit = 1, overflowed
// An object is only marked as overflowed when it is marked as live while
// the marking stack is overflowed.
static const int kMarkingBit = 0; // marking bit
static const int kMarkingMask = (1 << kMarkingBit); // marking mask
static const int kOverflowBit = 1; // overflow bit
static const int kOverflowMask = (1 << kOverflowBit); // overflow mask
// Forwarding pointers and map pointer encoding. On 32 bit all the bits are
// used.
// +-----------------+------------------+-----------------+
// |forwarding offset|page offset of map|page index of map|
// +-----------------+------------------+-----------------+
// ^ ^ ^
// | | |
// | | kMapPageIndexBits
// | kMapPageOffsetBits
// kForwardingOffsetBits
static const int kMapPageOffsetBits = kPageSizeBits - kMapAlignmentBits;
static const int kForwardingOffsetBits = kPageSizeBits - kObjectAlignmentBits;
#ifdef V8_HOST_ARCH_64_BIT
static const int kMapPageIndexBits = 16;
#else
// Use all the 32-bits to encode on a 32-bit platform.
static const int kMapPageIndexBits =
32 - (kMapPageOffsetBits + kForwardingOffsetBits);
#endif
static const int kMapPageIndexShift = 0;
static const int kMapPageOffsetShift =
kMapPageIndexShift + kMapPageIndexBits;
static const int kForwardingOffsetShift =
kMapPageOffsetShift + kMapPageOffsetBits;
// Bit masks covering the different parts the encoding.
static const uintptr_t kMapPageIndexMask =
(1 << kMapPageOffsetShift) - 1;
static const uintptr_t kMapPageOffsetMask =
((1 << kForwardingOffsetShift) - 1) & ~kMapPageIndexMask;
static const uintptr_t kForwardingOffsetMask =
~(kMapPageIndexMask | kMapPageOffsetMask);
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();
inline void set_map(Map* value);
// During garbage collection, the map word of a heap object does not
// necessarily contain a map pointer.
inline MapWord map_word();
inline void set_map_word(MapWord map_word);
// Converts an address to a HeapObject pointer.
static inline HeapObject* FromAddress(Address address);
// Returns the address of this HeapObject.
inline Address address();
// Iterates over pointers contained in the object (including the Map)
void Iterate(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.
void IterateBody(InstanceType type, int object_size, ObjectVisitor* v);
// 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);
// Support for the marking heap objects during the marking phase of GC.
// True if the object is marked live.
inline bool IsMarked();
// Mutate this object's map pointer to indicate that the object is live.
inline void SetMark();
// Mutate this object's map pointer to remove the indication that the
// object is live (ie, partially restore the map pointer).
inline void ClearMark();
// True if this object is marked as overflowed. Overflowed objects have
// been reached and marked during marking of the heap, but their children
// have not necessarily been marked and they have not been pushed on the
// marking stack.
inline bool IsOverflowed();
// Mutate this object's map pointer to indicate that the object is
// overflowed.
inline void SetOverflow();
// Mutate this object's map pointer to remove the indication that the
// object is overflowed (ie, partially restore the map pointer).
inline void ClearOverflow();
// 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);
// Casting.
static inline HeapObject* cast(Object* obj);
// Return the write barrier mode for this. Callers of this function
// must be able to present a reference to an AssertNoAllocation
// 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 AssertNoAllocation&);
// Dispatched behavior.
void HeapObjectShortPrint(StringStream* accumulator);
#ifdef DEBUG
void HeapObjectPrint();
void HeapObjectVerify();
inline void VerifyObjectField(int offset);
inline void VerifySmiField(int offset);
void PrintHeader(const char* id);
// Verify a pointer is a valid HeapObject pointer that points to object
// areas in the heap.
static void VerifyHeapPointer(Object* p);
#endif
// Layout description.
// First field in a heap object is map.
static const int kMapOffset = Object::kHeaderSize;
static const int kHeaderSize = kMapOffset + kPointerSize;
STATIC_CHECK(kMapOffset == Internals::kHeapObjectMapOffset);
protected:
// helpers for calling an ObjectVisitor to iterate over pointers in the
// half-open range [start, end) specified as integer offsets
inline void IteratePointers(ObjectVisitor* v, int start, int end);
// as above, for the single element at "offset"
inline void IteratePointer(ObjectVisitor* v, int offset);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(HeapObject);
};
#define SLOT_ADDR(obj, offset) \
reinterpret_cast<Object**>((obj)->address() + offset)
// This class describes a body of an object of a fixed size
// in which all pointer fields are located in the [start_offset, end_offset)
// interval.
template<int start_offset, int end_offset, int size>
class FixedBodyDescriptor {
public:
static const int kStartOffset = start_offset;
static const int kEndOffset = end_offset;
static const int kSize = size;
static inline void IterateBody(HeapObject* obj, ObjectVisitor* v);
template<typename StaticVisitor>
static inline void IterateBody(HeapObject* obj) {
StaticVisitor::VisitPointers(SLOT_ADDR(obj, start_offset),
SLOT_ADDR(obj, end_offset));
}
};
// This class describes a body of an object of a variable size
// in which all pointer fields are located in the [start_offset, object_size)
// interval.
template<int start_offset>
class FlexibleBodyDescriptor {
public:
static const int kStartOffset = start_offset;
static inline void IterateBody(HeapObject* obj,
int object_size,
ObjectVisitor* v);
template<typename StaticVisitor>
static inline void IterateBody(HeapObject* obj, int object_size) {
StaticVisitor::VisitPointers(SLOT_ADDR(obj, start_offset),
SLOT_ADDR(obj, object_size));
}
};
#undef SLOT_ADDR
// 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();
inline void set_value(double value);
// Casting.
static inline HeapNumber* cast(Object* obj);
// Dispatched behavior.
Object* HeapNumberToBoolean();
void HeapNumberPrint();
void HeapNumberPrint(StringStream* accumulator);
#ifdef DEBUG
void HeapNumberVerify();
#endif
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. Our current platforms are all
// little endian apart from non-EABI arm which is little endian with big
// endian floating point word ordering!
#if !defined(V8_HOST_ARCH_ARM) || defined(USE_ARM_EABI)
static const int kMantissaOffset = kValueOffset;
static const int kExponentOffset = kValueOffset + 4;
#else
static const int kMantissaOffset = kValueOffset + 4;
static const int kExponentOffset = kValueOffset;
# define BIG_ENDIAN_FLOATING_POINT 1
#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 kMantissaBitsInTopWord = 20;
static const int kNonMantissaBitsInTopWord = 12;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(HeapNumber);
};
// 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 HeapObject {
public:
enum DeleteMode { NORMAL_DELETION, FORCE_DELETION };
enum ElementsKind {
// The only "fast" kind.
FAST_ELEMENTS,
// All the kinds below are "slow".
DICTIONARY_ELEMENTS,
PIXEL_ELEMENTS,
EXTERNAL_BYTE_ELEMENTS,
EXTERNAL_UNSIGNED_BYTE_ELEMENTS,
EXTERNAL_SHORT_ELEMENTS,
EXTERNAL_UNSIGNED_SHORT_ELEMENTS,
EXTERNAL_INT_ELEMENTS,
EXTERNAL_UNSIGNED_INT_ELEMENTS,
EXTERNAL_FLOAT_ELEMENTS
};
// [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();
inline StringDictionary* property_dictionary(); // Gets slow properties.
// [elements]: The elements (properties with names that are integers).
//
// Elements can be in two general modes: fast and slow. Each mode
// corrensponds 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 the two maps in this mode:
// fixed_array_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 elements is either a NumberDictionary or a
// PixelArray or an ExternalArray.
DECL_ACCESSORS(elements, HeapObject)
inline void initialize_elements();
MUST_USE_RESULT inline MaybeObject* ResetElements();
inline ElementsKind GetElementsKind();
inline bool HasFastElements();
inline bool HasDictionaryElements();
inline bool HasPixelElements();
inline bool HasExternalArrayElements();
inline bool HasExternalByteElements();
inline bool HasExternalUnsignedByteElements();
inline bool HasExternalShortElements();
inline bool HasExternalUnsignedShortElements();
inline bool HasExternalIntElements();
inline bool HasExternalUnsignedIntElements();
inline bool HasExternalFloatElements();
inline bool AllowsSetElementsLength();
inline NumberDictionary* element_dictionary(); // Gets slow elements.
// Requires: this->HasFastElements().
MUST_USE_RESULT inline MaybeObject* EnsureWritableFastElements();
// Collects elements starting at index 0.
// Undefined values are placed after non-undefined values.
// Returns the number of non-undefined values.
MUST_USE_RESULT MaybeObject* PrepareElementsForSort(uint32_t limit);
// As PrepareElementsForSort, but only on objects where elements is
// a dictionary, and it will stay a dictionary.
MUST_USE_RESULT MaybeObject* PrepareSlowElementsForSort(uint32_t limit);
MUST_USE_RESULT MaybeObject* SetProperty(String* key,
Object* value,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* SetProperty(LookupResult* result,
String* key,
Object* value,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* SetPropertyWithFailedAccessCheck(
LookupResult* result,
String* name,
Object* value);
MUST_USE_RESULT MaybeObject* SetPropertyWithCallback(Object* structure,
String* name,
Object* value,
JSObject* holder);
MUST_USE_RESULT MaybeObject* SetPropertyWithDefinedSetter(JSFunction* setter,
Object* value);
MUST_USE_RESULT MaybeObject* SetPropertyWithInterceptor(
String* name,
Object* value,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* SetPropertyPostInterceptor(
String* name,
Object* value,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* IgnoreAttributesAndSetLocalProperty(
String* key,
Object* value,
PropertyAttributes attributes);
// Retrieve a value in a normalized object given a lookup result.
// Handles the special representation of JS global objects.
Object* GetNormalizedProperty(LookupResult* result);
// Sets the property value in a normalized object given a lookup result.
// Handles the special representation of JS global objects.
Object* SetNormalizedProperty(LookupResult* result, Object* value);
// Sets the property value in a normalized object given (key, value, details).
// Handles the special representation of JS global objects.
MUST_USE_RESULT MaybeObject* SetNormalizedProperty(String* name,
Object* value,
PropertyDetails details);
// Deletes the named property in a normalized object.
MUST_USE_RESULT MaybeObject* DeleteNormalizedProperty(String* name,
DeleteMode mode);
// Returns the class name ([[Class]] property in the specification).
String* class_name();
// Returns the constructor name (the name (possibly, inferred name) of the
// function that was used to instantiate the object).
String* constructor_name();
// Retrieve interceptors.
InterceptorInfo* GetNamedInterceptor();
InterceptorInfo* GetIndexedInterceptor();
inline PropertyAttributes GetPropertyAttribute(String* name);
PropertyAttributes GetPropertyAttributeWithReceiver(JSObject* receiver,
String* name);
PropertyAttributes GetLocalPropertyAttribute(String* name);
MUST_USE_RESULT MaybeObject* DefineAccessor(String* name,
bool is_getter,
JSFunction* fun,
PropertyAttributes attributes);
Object* LookupAccessor(String* name, bool is_getter);
MUST_USE_RESULT MaybeObject* DefineAccessor(AccessorInfo* info);
// Used from Object::GetProperty().
MaybeObject* GetPropertyWithFailedAccessCheck(
Object* receiver,
LookupResult* result,
String* name,
PropertyAttributes* attributes);
MaybeObject* GetPropertyWithInterceptor(
JSObject* receiver,
String* name,
PropertyAttributes* attributes);
MaybeObject* GetPropertyPostInterceptor(
JSObject* receiver,
String* name,
PropertyAttributes* attributes);
MaybeObject* GetLocalPropertyPostInterceptor(JSObject* receiver,
String* name,
PropertyAttributes* attributes);
// Returns true if this is an instance of an api function and has
// been modified since it was created. May give false positives.
bool IsDirty();
bool HasProperty(String* name) {
return GetPropertyAttribute(name) != ABSENT;
}
// Can cause a GC if it hits an interceptor.
bool HasLocalProperty(String* name) {
return GetLocalPropertyAttribute(name) != ABSENT;
}
// If the receiver is a JSGlobalProxy this method will return its prototype,
// otherwise the result is the receiver itself.
inline Object* BypassGlobalProxy();
// Accessors for hidden properties object.
//
// Hidden properties are not local properties of the object itself.
// Instead they are stored on an auxiliary JSObject stored as a local
// property with a special name Heap::hidden_symbol(). But if the
// receiver is a JSGlobalProxy then the auxiliary object is a property
// of its prototype.
//
// Has/Get/SetHiddenPropertiesObject methods don't allow the holder to be
// a JSGlobalProxy. Use BypassGlobalProxy method above to get to the real
// holder.
//
// These accessors do not touch interceptors or accessors.
inline bool HasHiddenPropertiesObject();
inline Object* GetHiddenPropertiesObject();
MUST_USE_RESULT inline MaybeObject* SetHiddenPropertiesObject(
Object* hidden_obj);
MUST_USE_RESULT MaybeObject* DeleteProperty(String* name, DeleteMode mode);
MUST_USE_RESULT MaybeObject* DeleteElement(uint32_t index, DeleteMode mode);
// Tests for the fast common case for property enumeration.
bool IsSimpleEnum();
// Do we want to keep the elements in fast case when increasing the
// capacity?
bool ShouldConvertToSlowElements(int new_capacity);
// Returns true if the backing storage for the slow-case elements of
// this object takes up nearly as much space as a fast-case backing
// storage would. In that case the JSObject should have fast
// elements.
bool ShouldConvertToFastElements();
// Return the object's prototype (might be Heap::null_value()).
inline Object* GetPrototype();
// Set the object's prototype (only JSObject and null are allowed).
MUST_USE_RESULT MaybeObject* SetPrototype(Object* value,
bool skip_hidden_prototypes);
// Tells whether the index'th element is present.
inline bool HasElement(uint32_t index);
bool HasElementWithReceiver(JSObject* receiver, uint32_t index);
// Tells whether the index'th element is present and how it is stored.
enum LocalElementType {
// There is no element with given index.
UNDEFINED_ELEMENT,
// Element with given index is handled by interceptor.
INTERCEPTED_ELEMENT,
// Element with given index is character in string.
STRING_CHARACTER_ELEMENT,
// Element with given index is stored in fast backing store.
FAST_ELEMENT,
// Element with given index is stored in slow backing store.
DICTIONARY_ELEMENT
};
LocalElementType HasLocalElement(uint32_t index);
bool HasElementWithInterceptor(JSObject* receiver, uint32_t index);
bool HasElementPostInterceptor(JSObject* receiver, uint32_t index);
MUST_USE_RESULT MaybeObject* SetFastElement(uint32_t index, Object* value);
// Set the index'th array element.
// A Failure object is returned if GC is needed.
MUST_USE_RESULT MaybeObject* SetElement(uint32_t index, Object* value);
// Returns the index'th element.
// The undefined object if index is out of bounds.
MaybeObject* GetElementWithReceiver(JSObject* receiver, uint32_t index);
MaybeObject* GetElementWithInterceptor(JSObject* receiver, uint32_t index);
MUST_USE_RESULT MaybeObject* SetFastElementsCapacityAndLength(int capacity,
int length);
MUST_USE_RESULT MaybeObject* SetSlowElements(Object* length);
// 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).
bool HasRealNamedProperty(String* key);
bool HasRealElementProperty(uint32_t index);
bool HasRealNamedCallbackProperty(String* key);
// Initializes the array to a certain length
MUST_USE_RESULT MaybeObject* SetElementsLength(Object* length);
// Get the header size for a JSObject. Used to compute the index of
// internal fields as well as the number of internal fields.
inline int GetHeaderSize();
inline int GetInternalFieldCount();
inline Object* GetInternalField(int index);
inline void SetInternalField(int index, Object* value);
// Lookup a property. If found, the result is valid and has
// detailed information.
void LocalLookup(String* name, LookupResult* result);
void Lookup(String* name, LookupResult* result);
// The following lookup functions skip interceptors.
void LocalLookupRealNamedProperty(String* name, LookupResult* result);
void LookupRealNamedProperty(String* name, LookupResult* result);
void LookupRealNamedPropertyInPrototypes(String* name, LookupResult* result);
void LookupCallbackSetterInPrototypes(String* name, LookupResult* result);
bool SetElementWithCallbackSetterInPrototypes(uint32_t index, Object* value);
void LookupCallback(String* name, LookupResult* result);
// Returns the number of properties on this object filtering out properties
// with the specified attributes (ignoring interceptors).
int NumberOfLocalProperties(PropertyAttributes filter);
// Returns the number of enumerable properties (ignoring interceptors).
int NumberOfEnumProperties();
// Fill in details for properties into storage starting at the specified
// index.
void GetLocalPropertyNames(FixedArray* storage, int index);
// Returns the number of properties on this object filtering out properties
// with the specified attributes (ignoring interceptors).
int NumberOfLocalElements(PropertyAttributes filter);
// Returns the number of enumerable elements (ignoring interceptors).
int NumberOfEnumElements();
// Returns the number of elements on this object filtering out elements
// with the specified attributes (ignoring interceptors).
int GetLocalElementKeys(FixedArray* storage, PropertyAttributes filter);
// Count and fill in the enumerable elements into storage.
// (storage->length() == NumberOfEnumElements()).
// If storage is NULL, will count the elements without adding
// them to any storage.
// Returns the number of enumerable elements.
int GetEnumElementKeys(FixedArray* storage);
// Add a property to a fast-case object using a map transition to
// new_map.
MUST_USE_RESULT MaybeObject* AddFastPropertyUsingMap(Map* new_map,
String* name,
Object* value);
// Add a constant function property to a fast-case object.
// This leaves a CONSTANT_TRANSITION in the old map, and
// if it is called on a second object with this map, a
// normal property is added instead, with a map transition.
// This avoids the creation of many maps with the same constant
// function, all orphaned.
MUST_USE_RESULT MaybeObject* AddConstantFunctionProperty(
String* name,
JSFunction* function,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* ReplaceSlowProperty(
String* name,
Object* value,
PropertyAttributes attributes);
// Converts a descriptor of any other type to a real field,
// backed by the properties array. Descriptors of visible
// types, such as CONSTANT_FUNCTION, keep their enumeration order.
// Converts the descriptor on the original object's map to a
// map transition, and the the new field is on the object's new map.
MUST_USE_RESULT MaybeObject* ConvertDescriptorToFieldAndMapTransition(
String* name,
Object* new_value,
PropertyAttributes attributes);
// Converts a descriptor of any other type to a real field,
// backed by the properties array. Descriptors of visible
// types, such as CONSTANT_FUNCTION, keep their enumeration order.
MUST_USE_RESULT MaybeObject* ConvertDescriptorToField(
String* name,
Object* new_value,
PropertyAttributes attributes);
// Add a property to a fast-case object.
MUST_USE_RESULT MaybeObject* AddFastProperty(String* name,
Object* value,
PropertyAttributes attributes);
// Add a property to a slow-case object.
MUST_USE_RESULT MaybeObject* AddSlowProperty(String* name,
Object* value,
PropertyAttributes attributes);
// Add a property to an object.
MUST_USE_RESULT MaybeObject* AddProperty(String* name,
Object* value,
PropertyAttributes attributes);
// 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.
MUST_USE_RESULT MaybeObject* NormalizeProperties(
PropertyNormalizationMode mode,
int expected_additional_properties);
MUST_USE_RESULT MaybeObject* NormalizeElements();
MUST_USE_RESULT MaybeObject* UpdateMapCodeCache(String* name, Code* code);
// Transform slow named properties to fast variants.
// Returns failure if allocation failed.
MUST_USE_RESULT MaybeObject* TransformToFastProperties(
int unused_property_fields);
// Access fast-case object properties at index.
inline Object* FastPropertyAt(int index);
inline Object* FastPropertyAtPut(int index, Object* value);
// Access to in object properties.
inline Object* InObjectPropertyAt(int index);
inline Object* InObjectPropertyAtPut(int index,
Object* value,
WriteBarrierMode mode
= UPDATE_WRITE_BARRIER);
// initializes the body after properties slot, properties slot is
// initialized by set_properties
// Note: this call does not update write barrier, it is caller's
// reponsibility to ensure that *v* can be collected without WB here.
inline void InitializeBody(int object_size, Object* value);
// Check whether this object references another object
bool ReferencesObject(Object* obj);
// Casting.
static inline JSObject* cast(Object* obj);
// Disalow further properties to be added to the object.
MUST_USE_RESULT MaybeObject* PreventExtensions();
// Dispatched behavior.
void JSObjectShortPrint(StringStream* accumulator);
#ifdef DEBUG
void JSObjectPrint();
void JSObjectVerify();
void PrintProperties();
void PrintElements();
// 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
Object* SlowReverseLookup(Object* value);
// Maximal number of fast properties for the JSObject. Used to
// restrict the number of map transitions to avoid an explosion in
// the number of maps for objects used as dictionaries.
inline int MaxFastProperties();
// Maximal number of elements (numbered 0 .. kMaxElementCount - 1).
// Also maximal value of JSArray's length property.
static const uint32_t kMaxElementCount = 0xffffffffu;
static const uint32_t kMaxGap = 1024;
static const int kMaxFastElementsLength = 5000;
static const int kInitialMaxFastElementArray = 100000;
static const int kMaxFastProperties = 8;
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 kPropertiesOffset = HeapObject::kHeaderSize;
static const int kElementsOffset = kPropertiesOffset + kPointerSize;
static const int kHeaderSize = kElementsOffset + kPointerSize;
STATIC_CHECK(kHeaderSize == Internals::kJSObjectHeaderSize);
class BodyDescriptor : public FlexibleBodyDescriptor<kPropertiesOffset> {
public:
static inline int SizeOf(Map* map, HeapObject* object);
};
private:
MUST_USE_RESULT MaybeObject* GetElementWithCallback(Object* receiver,
Object* structure,
uint32_t index,
Object* holder);
MaybeObject* SetElementWithCallback(Object* structure,
uint32_t index,
Object* value,
JSObject* holder);
MUST_USE_RESULT MaybeObject* SetElementWithInterceptor(uint32_t index,
Object* value);
MUST_USE_RESULT MaybeObject* SetElementWithoutInterceptor(uint32_t index,
Object* value);
MaybeObject* GetElementPostInterceptor(JSObject* receiver, uint32_t index);
MUST_USE_RESULT MaybeObject* DeletePropertyPostInterceptor(String* name,
DeleteMode mode);
MUST_USE_RESULT MaybeObject* DeletePropertyWithInterceptor(String* name);
MUST_USE_RESULT MaybeObject* DeleteElementPostInterceptor(uint32_t index,
DeleteMode mode);
MUST_USE_RESULT MaybeObject* DeleteElementWithInterceptor(uint32_t index);
PropertyAttributes GetPropertyAttributePostInterceptor(JSObject* receiver,
String* name,
bool continue_search);
PropertyAttributes GetPropertyAttributeWithInterceptor(JSObject* receiver,
String* name,
bool continue_search);
PropertyAttributes GetPropertyAttributeWithFailedAccessCheck(
Object* receiver,
LookupResult* result,
String* name,
bool continue_search);
PropertyAttributes GetPropertyAttribute(JSObject* receiver,
LookupResult* result,
String* name,
bool continue_search);
// Returns true if most of the elements backing storage is used.
bool HasDenseElements();
bool CanSetCallback(String* name);
MUST_USE_RESULT MaybeObject* SetElementCallback(
uint32_t index,
Object* structure,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* SetPropertyCallback(
String* name,
Object* structure,
PropertyAttributes attributes);
MUST_USE_RESULT MaybeObject* DefineGetterSetter(
String* name,
PropertyAttributes attributes);
void LookupInDescriptor(String* name, LookupResult* result);
DISALLOW_IMPLICIT_CONSTRUCTORS(JSObject);
};
// FixedArray describes fixed-sized arrays with element type Object*.
class FixedArray: public HeapObject {
public:
// [length]: length of the array.
inline int length();
inline void set_length(int value);
// Setter and getter for elements.
inline Object* get(int index);
// Setter that uses write barrier.
inline void set(int index, Object* value);
// Setter that doesn't need write barrier).
inline void set(int index, Smi* value);
// Setter with explicit barrier mode.
inline void set(int index, Object* value, WriteBarrierMode mode);
// Setters for frequently used oddballs located in old space.
inline void set_undefined(int index);
inline void set_null(int index);
inline void set_the_hole(int index);
// Setters with less debug checks for the GC to use.
inline void set_unchecked(int index, Smi* value);
inline void set_null_unchecked(int index);
inline void set_unchecked(int index, Object* value, WriteBarrierMode mode);
// Gives access to raw memory which stores the array's data.
inline Object** data_start();
// Copy operations.
MUST_USE_RESULT inline MaybeObject* Copy();
MUST_USE_RESULT MaybeObject* CopySize(int new_length);
// Add the elements of a JSArray to this FixedArray.
MUST_USE_RESULT MaybeObject* AddKeysFromJSArray(JSArray* array);
// Compute the union of this and other.
MUST_USE_RESULT MaybeObject* UnionOfKeys(FixedArray* other);
// Copy a sub array from the receiver to dest.
void CopyTo(int pos, FixedArray* dest, int dest_pos, int len);
// Garbage collection support.
static int SizeFor(int length) { return kHeaderSize + length * kPointerSize; }
// Code Generation support.
static int OffsetOfElementAt(int index) { return SizeFor(index); }
// Casting.
static inline FixedArray* cast(Object* obj);
// Layout description.
// Length is smi tagged when it is stored.
static const int kLengthOffset = HeapObject::kHeaderSize;
static const int kHeaderSize = kLengthOffset + kPointerSize;
// Maximal allowed size, in bytes, of a single FixedArray.
// Prevents overflowing size computations, as well as extreme memory
// consumption.
static const int kMaxSize = 512 * MB;
// Maximally allowed length of a FixedArray.
static const int kMaxLength = (kMaxSize - kHeaderSize) / kPointerSize;
// Dispatched behavior.
#ifdef DEBUG
void FixedArrayPrint();
void FixedArrayVerify();
// Checks if two FixedArrays have identical contents.
bool IsEqualTo(FixedArray* other);
#endif
// Swap two elements in a pair of arrays. If this array and the
// numbers array are the same object, the elements are only swapped
// once.
void SwapPairs(FixedArray* numbers, int i, int j);
// Sort prefix of this array and the numbers array as pairs wrt. the
// numbers. If the numbers array and the this array are the same
// object, the prefix of this array is sorted.
void SortPairs(FixedArray* numbers, uint32_t len);
class BodyDescriptor : public FlexibleBodyDescriptor<kHeaderSize> {
public:
static inline int SizeOf(Map* map, HeapObject* object) {
return SizeFor(reinterpret_cast<FixedArray*>(object)->length());
}
};
protected:
// Set operation on FixedArray without using write barriers. Can
// only be used for storing old space objects or smis.
static inline void fast_set(FixedArray* array, int index, Object* value);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(FixedArray);
};
// DescriptorArrays are fixed arrays used to hold instance descriptors.
// The format of the these objects is:
// [0]: point to a fixed array with (value, detail) pairs.
// [1]: next enumeration index (Smi), or pointer to small fixed array:
// [0]: next enumeration index (Smi)
// [1]: pointer to fixed array with enum cache
// [2]: first key
// [length() - 1]: last key
//
class DescriptorArray: public FixedArray {
public:
// Is this the singleton empty_descriptor_array?
inline bool IsEmpty();
// Returns the number of descriptors in the array.
int number_of_descriptors() {
return IsEmpty() ? 0 : length() - kFirstIndex;
}
int NextEnumerationIndex() {
if (IsEmpty()) return PropertyDetails::kInitialIndex;
Object* obj = get(kEnumerationIndexIndex);
if (obj->IsSmi()) {
return Smi::cast(obj)->value();
} else {
Object* index = FixedArray::cast(obj)->get(kEnumCacheBridgeEnumIndex);
return Smi::cast(index)->value();
}
}
// Set next enumeration index and flush any enum cache.
void SetNextEnumerationIndex(int value) {
if (!IsEmpty()) {
fast_set(this, kEnumerationIndexIndex, Smi::FromInt(value));
}
}
bool HasEnumCache() {
return !IsEmpty() && !get(kEnumerationIndexIndex)->IsSmi();
}
Object* GetEnumCache() {
ASSERT(HasEnumCache());
FixedArray* bridge = FixedArray::cast(get(kEnumerationIndexIndex));
return bridge->get(kEnumCacheBridgeCacheIndex);
}
// Initialize or change the enum cache,
// using the supplied storage for the small "bridge".
void SetEnumCache(FixedArray* bridge_storage, FixedArray* new_cache);
// Accessors for fetching instance descriptor at descriptor number.
inline String* GetKey(int descriptor_number);
inline Object* GetValue(int descriptor_number);
inline Smi* GetDetails(int descriptor_number);
inline PropertyType GetType(int descriptor_number);
inline int GetFieldIndex(int descriptor_number);
inline JSFunction* GetConstantFunction(int descriptor_number);
inline Object* GetCallbacksObject(int descriptor_number);
inline AccessorDescriptor* GetCallbacks(int descriptor_number);
inline bool IsProperty(int descriptor_number);
inline bool IsTransition(int descriptor_number);
inline bool IsNullDescriptor(int descriptor_number);
inline bool IsDontEnum(int descriptor_number);
// Accessor for complete descriptor.
inline void Get(int descriptor_number, Descriptor* desc);
inline void Set(int descriptor_number, Descriptor* desc);
// Transfer complete descriptor from another descriptor array to
// this one.
inline void CopyFrom(int index, DescriptorArray* src, int src_index);
// Copy the descriptor array, insert a new descriptor and optionally
// remove map transitions. If the descriptor is already present, it is
// replaced. If a replaced descriptor is a real property (not a transition
// or null), its enumeration index is kept as is.
// If adding a real property, map transitions must be removed. If adding
// a transition, they must not be removed. All null descriptors are removed.
MUST_USE_RESULT MaybeObject* CopyInsert(Descriptor* descriptor,
TransitionFlag transition_flag);
// Remove all transitions. Return a copy of the array with all transitions
// removed, or a Failure object if the new array could not be allocated.
MUST_USE_RESULT MaybeObject* RemoveTransitions();
// Sort the instance descriptors by the hash codes of their keys.
// Does not check for duplicates.
void SortUnchecked();
// Sort the instance descriptors by the hash codes of their keys.
// Checks the result for duplicates.
void Sort();
// Search the instance descriptors for given name.
inline int Search(String* name);
// As the above, but uses DescriptorLookupCache and updates it when
// necessary.
inline int SearchWithCache(String* name);
// Tells whether the name is present int the array.
bool Contains(String* name) { return kNotFound != Search(name); }
// Perform a binary search in the instance descriptors represented
// by this fixed array. low and high are descriptor indices. If there
// are three instance descriptors in this array it should be called
// with low=0 and high=2.
int BinarySearch(String* name, int low, int high);
// Perform a linear search in the instance descriptors represented
// by this fixed array. len is the number of descriptor indices that are
// valid. Does not require the descriptors to be sorted.
int LinearSearch(String* name, int len);
// Allocates a DescriptorArray, but returns the singleton
// empty descriptor array object if number_of_descriptors is 0.
MUST_USE_RESULT static MaybeObject* Allocate(int number_of_descriptors);
// Casting.
static inline DescriptorArray* cast(Object* obj);
// Constant for denoting key was not found.
static const int kNotFound = -1;
static const int kContentArrayIndex = 0;
static const int kEnumerationIndexIndex = 1;
static const int kFirstIndex = 2;
// The length of the "bridge" to the enum cache.
static const int kEnumCacheBridgeLength = 2;
static const int kEnumCacheBridgeEnumIndex = 0;
static const int kEnumCacheBridgeCacheIndex = 1;
// Layout description.
static const int kContentArrayOffset = FixedArray::kHeaderSize;
static const int kEnumerationIndexOffset = kContentArrayOffset + kPointerSize;
static const int kFirstOffset = kEnumerationIndexOffset + kPointerSize;
// Layout description for the bridge array.
static const int kEnumCacheBridgeEnumOffset = FixedArray::kHeaderSize;
static const int kEnumCacheBridgeCacheOffset =
kEnumCacheBridgeEnumOffset + kPointerSize;
#ifdef DEBUG
// Print all the descriptors.
void PrintDescriptors();
// Is the descriptor array sorted and without duplicates?
bool IsSortedNoDuplicates();
// Are two DescriptorArrays equal?
bool IsEqualTo(DescriptorArray* other);
#endif
// The maximum number of descriptors we want in a descriptor array (should
// fit in a page).
static const int kMaxNumberOfDescriptors = 1024 + 512;
private:
// Conversion from descriptor number to array indices.
static int ToKeyIndex(int descriptor_number) {
return descriptor_number+kFirstIndex;
}
static int ToDetailsIndex(int descriptor_number) {
return (descriptor_number << 1) + 1;
}
static int ToValueIndex(int descriptor_number) {
return descriptor_number << 1;
}
bool is_null_descriptor(int descriptor_number) {
return PropertyDetails(GetDetails(descriptor_number)).type() ==
NULL_DESCRIPTOR;
}
// Swap operation on FixedArray without using write barriers.
static inline void fast_swap(FixedArray* array, int first, int second);
// Swap descriptor first and second.
inline void Swap(int first, int second);
FixedArray* GetContentArray() {
return FixedArray::cast(get(kContentArrayIndex));
}
DISALLOW_IMPLICIT_CONSTRUCTORS(DescriptorArray);
};
// HashTable is a subclass of FixedArray that implements a hash table
// that uses open addressing and quadratic probing.
//
// In order for the quadratic probing to work, elements that have not
// yet been used and elements that have been deleted are
// distinguished. Probing continues when deleted elements are
// encountered and stops when unused elements are encountered.
//
// - Elements with key == undefined have not been used yet.
// - Elements with key == null have been deleted.
//
// The hash table class is parameterized with a Shape and a Key.
// Shape must be a class with the following interface:
// class ExampleShape {
// public:
// // Tells whether key matches other.
// static bool IsMatch(Key key, Object* other);
// // Returns the hash value for key.
// static uint32_t Hash(Key key);
// // Returns the hash value for object.
// static uint32_t HashForObject(Key key, Object* object);
// // Convert key to an object.
// static inline Object* AsObject(Key key);
// // The prefix size indicates number of elements in the beginning
// // of the backing storage.
// static const int kPrefixSize = ..;
// // The Element size indicates number of elements per entry.
// static const int kEntrySize = ..;
// };
// The prefix size indicates an amount of memory in the
// beginning of the backing storage that can be used for non-element
// information by subclasses.
template<typename Shape, typename Key>
class HashTable: public FixedArray {
public:
// Returns the number of elements in the hash table.
int NumberOfElements() {
return Smi::cast(get(kNumberOfElementsIndex))->value();
}
// Returns the number of deleted elements in the hash table.
int NumberOfDeletedElements() {
return Smi::cast(get(kNumberOfDeletedElementsIndex))->value();
}
// Returns the capacity of the hash table.
int Capacity() {
return Smi::cast(get(kCapacityIndex))->value();
}
// ElementAdded should be called whenever an element is added to a
// hash table.
void ElementAdded() { SetNumberOfElements(NumberOfElements() + 1); }
// ElementRemoved should be called whenever an element is removed from
// a hash table.
void ElementRemoved() {
SetNumberOfElements(NumberOfElements() - 1);
SetNumberOfDeletedElements(NumberOfDeletedElements() + 1);
}
void ElementsRemoved(int n) {
SetNumberOfElements(NumberOfElements() - n);
SetNumberOfDeletedElements(NumberOfDeletedElements() + n);
}
// Returns a new HashTable object. Might return Failure.
MUST_USE_RESULT static MaybeObject* Allocate(
int at_least_space_for,
PretenureFlag pretenure = NOT_TENURED);
// Returns the key at entry.
Object* KeyAt(int entry) { return get(EntryToIndex(entry)); }
// Tells whether k is a real key. Null and undefined are not allowed
// as keys and can be used to indicate missing or deleted elements.
bool IsKey(Object* k) {
return !k->IsNull() && !k->IsUndefined();
}
// Garbage collection support.
void IteratePrefix(ObjectVisitor* visitor);
void IterateElements(ObjectVisitor* visitor);
// Casting.
static inline HashTable* cast(Object* obj);
// Compute the probe offset (quadratic probing).
INLINE(static uint32_t GetProbeOffset(uint32_t n)) {
return (n + n * n) >> 1;
}
static const int kNumberOfElementsIndex = 0;
static const int kNumberOfDeletedElementsIndex = 1;
static const int kCapacityIndex = 2;
static const int kPrefixStartIndex = 3;
static const int kElementsStartIndex =
kPrefixStartIndex + Shape::kPrefixSize;
static const int kEntrySize = Shape::kEntrySize;
static const int kElementsStartOffset =
kHeaderSize + kElementsStartIndex * kPointerSize;
static const int kCapacityOffset =
kHeaderSize + kCapacityIndex * kPointerSize;
// Constant used for denoting a absent entry.
static const int kNotFound = -1;
// Maximal capacity of HashTable. Based on maximal length of underlying
// FixedArray. Staying below kMaxCapacity also ensures that EntryToIndex
// cannot overflow.
static const int kMaxCapacity =
(FixedArray::kMaxLength - kElementsStartOffset) / kEntrySize;
// Find entry for key otherwise return kNotFound.
int FindEntry(Key key);
protected:
// Find the entry at which to insert element with the given key that
// has the given hash value.
uint32_t FindInsertionEntry(uint32_t hash);
// Returns the index for an entry (of the key)
static inline int EntryToIndex(int entry) {
return (entry * kEntrySize) + kElementsStartIndex;
}
// Update the number of elements in the hash table.
void SetNumberOfElements(int nof) {
fast_set(this, kNumberOfElementsIndex, Smi::FromInt(nof));
}
// Update the number of deleted elements in the hash table.
void SetNumberOfDeletedElements(int nod) {
fast_set(this, kNumberOfDeletedElementsIndex, Smi::FromInt(nod));
}
// Sets the capacity of the hash table.
void SetCapacity(int capacity) {
// To scale a computed hash code to fit within the hash table, we
// use bit-wise AND with a mask, so the capacity must be positive
// and non-zero.
ASSERT(capacity > 0);
ASSERT(capacity <= kMaxCapacity);
fast_set(this, kCapacityIndex, Smi::FromInt(capacity));
}
// Returns probe entry.
static uint32_t GetProbe(uint32_t hash, uint32_t number, uint32_t size) {
ASSERT(IsPowerOf2(size));
return (hash + GetProbeOffset(number)) & (size - 1);
}
static uint32_t FirstProbe(uint32_t hash, uint32_t size) {
return hash & (size - 1);
}
static uint32_t NextProbe(uint32_t last, uint32_t number, uint32_t size) {
return (last + number) & (size - 1);
}
// Ensure enough space for n additional elements.
MUST_USE_RESULT MaybeObject* EnsureCapacity(int n, Key key);
};
// HashTableKey is an abstract superclass for virtual key behavior.
class HashTableKey {
public:
// Returns whether the other object matches this key.
virtual bool IsMatch(Object* other) = 0;
// Returns the hash value for this key.
virtual uint32_t Hash() = 0;
// Returns the hash value for object.
virtual uint32_t HashForObject(Object* key) = 0;
// Returns the key object for storing into the hash table.
// If allocations fails a failure object is returned.
MUST_USE_RESULT virtual MaybeObject* AsObject() = 0;
// Required.
virtual ~HashTableKey() {}
};
class SymbolTableShape {
public:
static bool IsMatch(HashTableKey* key, Object* value) {
return key->IsMatch(value);
}
static uint32_t Hash(HashTableKey* key) {
return key->Hash();
}
static uint32_t HashForObject(HashTableKey* key, Object* object) {
return key->HashForObject(object);
}
MUST_USE_RESULT static MaybeObject* AsObject(HashTableKey* key) {
return key->AsObject();
}
static const int kPrefixSize = 0;
static const int kEntrySize = 1;
};
// SymbolTable.
//
// No special elements in the prefix and the element size is 1
// because only the symbol itself (the key) needs to be stored.
class SymbolTable: public HashTable<SymbolTableShape, HashTableKey*> {
public:
// Find symbol in the symbol table. If it is not there yet, it is
// added. The return value is the symbol table which might have
// been enlarged. If the return value is not a failure, the symbol
// pointer *s is set to the symbol found.
MUST_USE_RESULT MaybeObject* LookupSymbol(Vector<const char> str, Object** s);
MUST_USE_RESULT MaybeObject* LookupString(String* key, Object** s);
// Looks up a symbol that is equal to the given string and returns
// true if it is found, assigning the symbol to the given output
// parameter.
bool LookupSymbolIfExists(String* str, String** symbol);
bool LookupTwoCharsSymbolIfExists(uint32_t c1, uint32_t c2, String** symbol);
// Casting.
static inline SymbolTable* cast(Object* obj);
private:
MUST_USE_RESULT MaybeObject* LookupKey(HashTableKey* key, Object** s);
DISALLOW_IMPLICIT_CONSTRUCTORS(SymbolTable);
};
class MapCacheShape {
public:
static bool IsMatch(HashTableKey* key, Object* value) {
return key->IsMatch(value);
}
static uint32_t Hash(HashTableKey* key) {
return key->Hash();
}
static uint32_t HashForObject(HashTableKey* key, Object* object) {
return key->HashForObject(object);
}
MUST_USE_RESULT static MaybeObject* AsObject(HashTableKey* key) {
return key->AsObject();
}
static const int kPrefixSize = 0;
static const int kEntrySize = 2;
};
// MapCache.
//
// Maps keys that are a fixed array of symbols to a map.
// Used for canonicalize maps for object literals.
class MapCache: public HashTable<MapCacheShape, HashTableKey*> {
public:
// Find cached value for a string key, otherwise return null.
Object* Lookup(FixedArray* key);
MUST_USE_RESULT MaybeObject* Put(FixedArray* key, Map* value);
static inline MapCache* cast(Object* obj);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(MapCache);
};
template <typename Shape, typename Key>
class Dictionary: public HashTable<Shape, Key> {
public:
static inline Dictionary<Shape, Key>* cast(Object* obj) {
return reinterpret_cast<Dictionary<Shape, Key>*>(obj);
}
// Returns the value at entry.
Object* ValueAt(int entry) {
return this->get(HashTable<Shape, Key>::EntryToIndex(entry)+1);
}
// Set the value for entry.
void ValueAtPut(int entry, Object* value) {
// Check that this value can actually be written.
PropertyDetails details = DetailsAt(entry);
// If a value has not been initilized we allow writing to it even if
// it is read only (a declared const that has not been initialized).
if (details.IsReadOnly() && !ValueAt(entry)->IsTheHole()) return;
this->set(HashTable<Shape, Key>::EntryToIndex(entry)+1, value);
}
// Returns the property details for the property at entry.
PropertyDetails DetailsAt(int entry) {
ASSERT(entry >= 0); // Not found is -1, which is not caught by get().
return PropertyDetails(
Smi::cast(this->get(HashTable<Shape, Key>::EntryToIndex(entry) + 2)));
}
// Set the details for entry.
void DetailsAtPut(int entry, PropertyDetails value) {
this->set(HashTable<Shape, Key>::EntryToIndex(entry) + 2, value.AsSmi());
}
// Sorting support
void CopyValuesTo(FixedArray* elements);
// Delete a property from the dictionary.
Object* DeleteProperty(int entry, JSObject::DeleteMode mode);
// Returns the number of elements in the dictionary filtering out properties
// with the specified attributes.
int NumberOfElementsFilterAttributes(PropertyAttributes filter);
// Returns the number of enumerable elements in the dictionary.
int NumberOfEnumElements();
// Copies keys to preallocated fixed array.
void CopyKeysTo(FixedArray* storage, PropertyAttributes filter);
// Fill in details for properties into storage.
void CopyKeysTo(FixedArray* storage);
// Accessors for next enumeration index.
void SetNextEnumerationIndex(int index) {
this->fast_set(this, kNextEnumerationIndexIndex, Smi::FromInt(index));
}
int NextEnumerationIndex() {
return Smi::cast(FixedArray::get(kNextEnumerationIndexIndex))->value();
}
// Returns a new array for dictionary usage. Might return Failure.
MUST_USE_RESULT static MaybeObject* Allocate(int at_least_space_for);
// Ensure enough space for n additional elements.
MUST_USE_RESULT MaybeObject* EnsureCapacity(int n, Key key);
#ifdef DEBUG
void Print();
#endif
// Returns the key (slow).
Object* SlowReverseLookup(Object* value);
// Sets the entry to (key, value) pair.
inline void SetEntry(int entry,
Object* key,
Object* value,
PropertyDetails details);
MUST_USE_RESULT MaybeObject* Add(Key key,
Object* value,
PropertyDetails details);
protected:
// Generic at put operation.
MUST_USE_RESULT MaybeObject* AtPut(Key key, Object* value);
// Add entry to dictionary.
MUST_USE_RESULT MaybeObject* AddEntry(Key key,
Object* value,
PropertyDetails details,
uint32_t hash);
// Generate new enumeration indices to avoid enumeration index overflow.
MUST_USE_RESULT MaybeObject* GenerateNewEnumerationIndices();
static const int kMaxNumberKeyIndex =
HashTable<Shape, Key>::kPrefixStartIndex;
static const int kNextEnumerationIndexIndex = kMaxNumberKeyIndex + 1;
};
class StringDictionaryShape {
public:
static inline bool IsMatch(String* key, Object* other);
static inline uint32_t Hash(String* key);
static inline uint32_t HashForObject(String* key, Object* object);
MUST_USE_RESULT static inline MaybeObject* AsObject(String* key);
static const int kPrefixSize = 2;
static const int kEntrySize = 3;
static const bool kIsEnumerable = true;
};
class StringDictionary: public Dictionary<StringDictionaryShape, String*> {
public:
static inline StringDictionary* cast(Object* obj) {
ASSERT(obj->IsDictionary());
return reinterpret_cast<StringDictionary*>(obj);
}
// Copies enumerable keys to preallocated fixed array.
void CopyEnumKeysTo(FixedArray* storage, FixedArray* sort_array);
// For transforming properties of a JSObject.
MUST_USE_RESULT MaybeObject* TransformPropertiesToFastFor(
JSObject* obj,
int unused_property_fields);
// Find entry for key otherwise return kNotFound. Optimzed version of
// HashTable::FindEntry.
int FindEntry(String* key);
};
class NumberDictionaryShape {
public:
static inline bool IsMatch(uint32_t key, Object* other);
static inline uint32_t Hash(uint32_t key);
static inline uint32_t HashForObject(uint32_t key, Object* object);
MUST_USE_RESULT static inline MaybeObject* AsObject(uint32_t key);
static const int kPrefixSize = 2;
static const int kEntrySize = 3;
static const bool kIsEnumerable = false;
};
class NumberDictionary: public Dictionary<NumberDictionaryShape, uint32_t> {
public:
static NumberDictionary* cast(Object* obj) {
ASSERT(obj->IsDictionary());
return reinterpret_cast<NumberDictionary*>(obj);
}
// Type specific at put (default NONE attributes is used when adding).
MUST_USE_RESULT MaybeObject* AtNumberPut(uint32_t key, Object* value);
MUST_USE_RESULT MaybeObject* AddNumberEntry(uint32_t key,
Object* value,
PropertyDetails details);
// Set an existing entry or add a new one if needed.
MUST_USE_RESULT MaybeObject* Set(uint32_t key,
Object* value,
PropertyDetails details);
void UpdateMaxNumberKey(uint32_t key);
// If slow elements are required we will never go back to fast-case
// for the elements kept in this dictionary. We require slow
// elements if an element has been added at an index larger than
// kRequiresSlowElementsLimit or set_requires_slow_elements() has been called
// when defining a getter or setter with a number key.
inline bool requires_slow_elements();
inline void set_requires_slow_elements();
// Get the value of the max number key that has been added to this
// dictionary. max_number_key can only be called if
// requires_slow_elements returns false.
inline uint32_t max_number_key();
// Remove all entries were key is a number and (from <= key && key < to).
void RemoveNumberEntries(uint32_t from, uint32_t to);
// Bit masks.
static const int kRequiresSlowElementsMask = 1;
static const int kRequiresSlowElementsTagSize = 1;
static const uint32_t kRequiresSlowElementsLimit = (1 << 29) - 1;
};
// JSFunctionResultCache caches results of some JSFunction invocation.
// It is a fixed array with fixed structure:
// [0]: factory function
// [1]: finger index
// [2]: current cache size
// [3]: dummy field.
// The rest of array are key/value pairs.
class JSFunctionResultCache: public FixedArray {
public:
static const int kFactoryIndex = 0;
static const int kFingerIndex = kFactoryIndex + 1;
static const int kCacheSizeIndex = kFingerIndex + 1;
static const int kDummyIndex = kCacheSizeIndex + 1;
static const int kEntriesIndex = kDummyIndex + 1;
static const int kEntrySize = 2; // key + value
static const int kFactoryOffset = kHeaderSize;
static const int kFingerOffset = kFactoryOffset + kPointerSize;
static const int kCacheSizeOffset = kFingerOffset + kPointerSize;
inline void MakeZeroSize();
inline void Clear();
// Casting
static inline JSFunctionResultCache* cast(Object* obj);
#ifdef DEBUG
void JSFunctionResultCacheVerify();
#endif
};
// The cache for maps used by normalized (dictionary mode) objects.
// Such maps do not have property descriptors, so a typical program
// needs very limited number of distinct normalized maps.
class NormalizedMapCache: public FixedArray {
public:
static const int kEntries = 64;
MUST_USE_RESULT MaybeObject* Get(JSObject* object,
PropertyNormalizationMode mode);
void Clear();
// Casting
static inline NormalizedMapCache* cast(Object* obj);
#ifdef DEBUG
void NormalizedMapCacheVerify();
#endif
private:
static int Hash(Map* fast);
static bool CheckHit(Map* slow, Map* fast, PropertyNormalizationMode mode);
};
// ByteArray represents fixed sized byte arrays. Used by the outside world,
// such as PCRE, and also by the memory allocator and garbage collector to
// fill in free blocks in the heap.
class ByteArray: public HeapObject {
public:
// [length]: length of the array.
inline int length();
inline void set_length(int value);
// Setter and getter.
inline byte get(int index);
inline void set(int index, byte value);
// Treat contents as an int array.
inline int get_int(int index);
static int SizeFor(int length) {
return OBJECT_POINTER_ALIGN(kHeaderSize + length);
}
// We use byte arrays for free blocks in the heap. Given a desired size in
// bytes that is a multiple of the word size and big enough to hold a byte
// array, this function returns the number of elements a byte array should
// have.
static int LengthFor(int size_in_bytes) {
ASSERT(IsAligned(size_in_bytes, kPointerSize));
ASSERT(size_in_bytes >= kHeaderSize);
return size_in_bytes - kHeaderSize;
}
// Returns data start address.
inline Address GetDataStartAddress();
// Returns a pointer to the ByteArray object for a given data start address.
static inline ByteArray* FromDataStartAddress(Address address);
// Casting.
static inline ByteArray* cast(Object* obj);
// Dispatched behavior.
inline int ByteArraySize() {
return SizeFor(this->length());
}
#ifdef DEBUG
void ByteArrayPrint();
void ByteArrayVerify();
#endif
// Layout description.
// Length is smi tagged when it is stored.
static const int kLengthOffset = HeapObject::kHeaderSize;
static const int kHeaderSize = kLengthOffset + kPointerSize;
static const int kAlignedSize = OBJECT_POINTER_ALIGN(kHeaderSize);
// Maximal memory consumption for a single ByteArray.
static const int kMaxSize = 512 * MB;
// Maximal length of a single ByteArray.
static const int kMaxLength = kMaxSize - kHeaderSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ByteArray);
};
// A PixelArray represents a fixed-size byte array with special semantics
// used for implementing the CanvasPixelArray object. Please see the
// specification at:
// http://www.whatwg.org/specs/web-apps/current-work/
// multipage/the-canvas-element.html#canvaspixelarray
// In particular, write access clamps the value written to 0 or 255 if the
// value written is outside this range.
class PixelArray: public HeapObject {
public:
// [length]: length of the array.
inline int length();
inline void set_length(int value);
// [external_pointer]: The pointer to the external memory area backing this
// pixel array.
DECL_ACCESSORS(external_pointer, uint8_t) // Pointer to the data store.
// Setter and getter.
inline uint8_t get(int index);
inline void set(int index, uint8_t value);
// This accessor applies the correct conversion from Smi, HeapNumber and
// undefined and clamps the converted value between 0 and 255.
Object* SetValue(uint32_t index, Object* value);
// Casting.
static inline PixelArray* cast(Object* obj);
#ifdef DEBUG
void PixelArrayPrint();
void PixelArrayVerify();
#endif // DEBUG
// Maximal acceptable length for a pixel array.
static const int kMaxLength = 0x3fffffff;
// PixelArray headers are not quadword aligned.
static const int kLengthOffset = HeapObject::kHeaderSize;
static const int kExternalPointerOffset =
POINTER_SIZE_ALIGN(kLengthOffset + kIntSize);
static const int kHeaderSize = kExternalPointerOffset + kPointerSize;
static const int kAlignedSize = OBJECT_POINTER_ALIGN(kHeaderSize);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(PixelArray);
};
// An ExternalArray represents a fixed-size array of primitive values
// which live outside the JavaScript heap. Its subclasses are used to
// implement the CanvasArray types being defined in the WebGL
// specification. As of this writing the first public draft is not yet
// available, but Khronos members can access the draft at:
// https://cvs.khronos.org/svn/repos/3dweb/trunk/doc/spec/WebGL-spec.html
//
// The semantics of these arrays differ from CanvasPixelArray.
// Out-of-range values passed to the setter are converted via a C
// cast, not clamping. Out-of-range indices cause exceptions to be
// raised rather than being silently ignored.
class ExternalArray: public HeapObject {
public:
// [length]: length of the array.
inline int length();
inline void set_length(int value);
// [external_pointer]: The pointer to the external memory area backing this
// external array.
DECL_ACCESSORS(external_pointer, void) // Pointer to the data store.
// Casting.
static inline ExternalArray* cast(Object* obj);
// Maximal acceptable length for an external array.
static const int kMaxLength = 0x3fffffff;
// ExternalArray headers are not quadword aligned.
static const int kLengthOffset = HeapObject::kHeaderSize;
static const int kExternalPointerOffset =
POINTER_SIZE_ALIGN(kLengthOffset + kIntSize);
static const int kHeaderSize = kExternalPointerOffset + kPointerSize;
static const int kAlignedSize = OBJECT_POINTER_ALIGN(kHeaderSize);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalArray);
};
class ExternalByteArray: public ExternalArray {
public:
// Setter and getter.
inline int8_t get(int index);
inline void set(int index, int8_t value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalByteArray* cast(Object* obj);
#ifdef DEBUG
void ExternalByteArrayPrint();
void ExternalByteArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalByteArray);
};
class ExternalUnsignedByteArray: public ExternalArray {
public:
// Setter and getter.
inline uint8_t get(int index);
inline void set(int index, uint8_t value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalUnsignedByteArray* cast(Object* obj);
#ifdef DEBUG
void ExternalUnsignedByteArrayPrint();
void ExternalUnsignedByteArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalUnsignedByteArray);
};
class ExternalShortArray: public ExternalArray {
public:
// Setter and getter.
inline int16_t get(int index);
inline void set(int index, int16_t value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalShortArray* cast(Object* obj);
#ifdef DEBUG
void ExternalShortArrayPrint();
void ExternalShortArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalShortArray);
};
class ExternalUnsignedShortArray: public ExternalArray {
public:
// Setter and getter.
inline uint16_t get(int index);
inline void set(int index, uint16_t value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalUnsignedShortArray* cast(Object* obj);
#ifdef DEBUG
void ExternalUnsignedShortArrayPrint();
void ExternalUnsignedShortArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalUnsignedShortArray);
};
class ExternalIntArray: public ExternalArray {
public:
// Setter and getter.
inline int32_t get(int index);
inline void set(int index, int32_t value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalIntArray* cast(Object* obj);
#ifdef DEBUG
void ExternalIntArrayPrint();
void ExternalIntArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalIntArray);
};
class ExternalUnsignedIntArray: public ExternalArray {
public:
// Setter and getter.
inline uint32_t get(int index);
inline void set(int index, uint32_t value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalUnsignedIntArray* cast(Object* obj);
#ifdef DEBUG
void ExternalUnsignedIntArrayPrint();
void ExternalUnsignedIntArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalUnsignedIntArray);
};
class ExternalFloatArray: public ExternalArray {
public:
// Setter and getter.
inline float get(int index);
inline void set(int index, float value);
// This accessor applies the correct conversion from Smi, HeapNumber
// and undefined.
MaybeObject* SetValue(uint32_t index, Object* value);
// Casting.
static inline ExternalFloatArray* cast(Object* obj);
#ifdef DEBUG
void ExternalFloatArrayPrint();
void ExternalFloatArrayVerify();
#endif // DEBUG
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalFloatArray);
};
// Code describes objects with on-the-fly generated machine code.
class Code: public HeapObject {
public:
// Opaque data type for encapsulating code flags like kind, inline
// cache state, and arguments count.
// FLAGS_MIN_VALUE and FLAGS_MAX_VALUE are specified to ensure that
// enumeration type has correct value range (see Issue 830 for more details).
enum Flags {
FLAGS_MIN_VALUE = kMinInt,
FLAGS_MAX_VALUE = kMaxInt
};
enum Kind {
FUNCTION,
STUB,
BUILTIN,
LOAD_IC,
KEYED_LOAD_IC,
CALL_IC,
KEYED_CALL_IC,
STORE_IC,
KEYED_STORE_IC,
BINARY_OP_IC,
// No more than 16 kinds. The value currently encoded in four bits in
// Flags.
// Pseudo-kinds.
REGEXP = BUILTIN,
FIRST_IC_KIND = LOAD_IC,
LAST_IC_KIND = BINARY_OP_IC
};
enum {
NUMBER_OF_KINDS = LAST_IC_KIND + 1
};
#ifdef ENABLE_DISASSEMBLER
// Printing
static const char* Kind2String(Kind kind);
static const char* ICState2String(InlineCacheState state);
static const char* PropertyType2String(PropertyType type);
void Disassemble(const char* name);
#endif // ENABLE_DISASSEMBLER
// [instruction_size]: Size of the native instructions
inline int instruction_size();
inline void set_instruction_size(int value);
// [relocation_info]: Code relocation information
DECL_ACCESSORS(relocation_info, ByteArray)
// Unchecked accessor to be used during GC.
inline ByteArray* unchecked_relocation_info();
inline int relocation_size();
// [flags]: Various code flags.
inline Flags flags();
inline void set_flags(Flags flags);
// [flags]: Access to specific code flags.
inline Kind kind();
inline InlineCacheState ic_state(); // Only valid for IC stubs.
inline InLoopFlag ic_in_loop(); // Only valid for IC stubs.
inline PropertyType type(); // Only valid for monomorphic IC stubs.
inline int arguments_count(); // Only valid for call IC stubs.
// Testers for IC stub kinds.
inline bool is_inline_cache_stub();
inline bool is_load_stub() { return kind() == LOAD_IC; }
inline bool is_keyed_load_stub() { return kind() == KEYED_LOAD_IC; }
inline bool is_store_stub() { return kind() == STORE_IC; }
inline bool is_keyed_store_stub() { return kind() == KEYED_STORE_IC; }
inline bool is_call_stub() { return kind() == CALL_IC; }
inline bool is_keyed_call_stub() { return kind() == KEYED_CALL_IC; }
// [major_key]: For kind STUB or BINARY_OP_IC, the major key.
inline int major_key();
inline void set_major_key(int major);
// Flags operations.
static inline Flags ComputeFlags(Kind kind,
InLoopFlag in_loop = NOT_IN_LOOP,
InlineCacheState ic_state = UNINITIALIZED,
PropertyType type = NORMAL,
int argc = -1,
InlineCacheHolderFlag holder = OWN_MAP);
static inline Flags ComputeMonomorphicFlags(
Kind kind,
PropertyType type,
InlineCacheHolderFlag holder = OWN_MAP,
InLoopFlag in_loop = NOT_IN_LOOP,
int argc = -1);
static inline Kind ExtractKindFromFlags(Flags flags);
static inline InlineCacheState ExtractICStateFromFlags(Flags flags);
static inline InLoopFlag ExtractICInLoopFromFlags(Flags flags);
static inline PropertyType ExtractTypeFromFlags(Flags flags);
static inline int ExtractArgumentsCountFromFlags(Flags flags);
static inline InlineCacheHolderFlag ExtractCacheHolderFromFlags(Flags flags);
static inline Flags RemoveTypeFromFlags(Flags flags);
// Convert a target address into a code object.
static inline Code* GetCodeFromTargetAddress(Address address);
// Convert an entry address into an object.
static inline Object* GetObjectFromEntryAddress(Address location_of_address);
// Returns the address of the first instruction.
inline byte* instruction_start();
// Returns the address right after the last instruction.
inline byte* instruction_end();
// Returns the size of the instructions, padding, and relocation information.
inline int body_size();
// Returns the address of the first relocation info (read backwards!).
inline byte* relocation_start();
// Code entry point.
inline byte* entry();
// Returns true if pc is inside this object's instructions.
inline bool contains(byte* pc);
// Relocate the code by delta bytes. Called to signal that this code
// object has been moved by delta bytes.
void Relocate(intptr_t delta);
// Migrate code described by desc.
void CopyFrom(const CodeDesc& desc);
// Returns the object size for a given body (used for allocation).
static int SizeFor(int body_size) {
ASSERT_SIZE_TAG_ALIGNED(body_size);
return RoundUp(kHeaderSize + body_size, kCodeAlignment);
}
// Calculate the size of the code object to report for log events. This takes
// the layout of the code object into account.
int ExecutableSize() {
// Check that the assumptions about the layout of the code object holds.
ASSERT_EQ(static_cast<int>(instruction_start() - address()),
Code::kHeaderSize);
return instruction_size() + Code::kHeaderSize;
}
// Locating source position.
int SourcePosition(Address pc);
int SourceStatementPosition(Address pc);
// Casting.
static inline Code* cast(Object* obj);
// Dispatched behavior.
int CodeSize() { return SizeFor(body_size()); }
inline void CodeIterateBody(ObjectVisitor* v);
template<typename StaticVisitor>
inline void CodeIterateBody();
#ifdef DEBUG
void CodePrint();
void CodeVerify();
#endif
// Layout description.
static const int kInstructionSizeOffset = HeapObject::kHeaderSize;
static const int kRelocationInfoOffset = kInstructionSizeOffset + kIntSize;
static const int kFlagsOffset = kRelocationInfoOffset + kPointerSize;
static const int kKindSpecificFlagsOffset = kFlagsOffset + kIntSize;
// Add padding to align the instruction start following right after
// the Code object header.
static const int kHeaderSize =
CODE_POINTER_ALIGN(kKindSpecificFlagsOffset + kIntSize);
// Byte offsets within kKindSpecificFlagsOffset.
static const int kStubMajorKeyOffset = kKindSpecificFlagsOffset + 1;
// Flags layout.
static const int kFlagsICStateShift = 0;
static const int kFlagsICInLoopShift = 3;
static const int kFlagsTypeShift = 4;
static const int kFlagsKindShift = 7;
static const int kFlagsICHolderShift = 11;
static const int kFlagsArgumentsCountShift = 12;
static const int kFlagsICStateMask = 0x00000007; // 00000000111
static const int kFlagsICInLoopMask = 0x00000008; // 00000001000
static const int kFlagsTypeMask = 0x00000070; // 00001110000
static const int kFlagsKindMask = 0x00000780; // 11110000000
static const int kFlagsCacheInPrototypeMapMask = 0x00000800;
static const int kFlagsArgumentsCountMask = 0xFFFFF000;
static const int kFlagsNotUsedInLookup =
(kFlagsICInLoopMask | kFlagsTypeMask | kFlagsCacheInPrototypeMapMask);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Code);
};
// All heap objects have a Map that describes their structure.
// A Map contains information about:
// - Size information about the object
// - How to iterate over an object (for garbage collection)
class Map: public HeapObject {
public:
// Instance size.
// Size in bytes or kVariableSizeSentinel if instances do not have
// a fixed size.
inline int instance_size();
inline void set_instance_size(int value);
// Count of properties allocated in the object.
inline int inobject_properties();
inline void set_inobject_properties(int value);
// Count of property fields pre-allocated in the object when first allocated.
inline int pre_allocated_property_fields();
inline void set_pre_allocated_property_fields(int value);
// Instance type.
inline InstanceType instance_type();
inline void set_instance_type(InstanceType value);
// Tells how many unused property fields are available in the
// instance (only used for JSObject in fast mode).
inline int unused_property_fields();
inline void set_unused_property_fields(int value);
// Bit field.
inline byte bit_field();
inline void set_bit_field(byte value);
// Bit field 2.
inline byte bit_field2();
inline void set_bit_field2(byte value);
// Tells whether the object in the prototype property will be used
// for instances created from this function. If the prototype
// property is set to a value that is not a JSObject, the prototype
// property will not be used to create instances of the function.
// See ECMA-262, 13.2.2.
inline void set_non_instance_prototype(bool value);
inline bool has_non_instance_prototype();
// Tells whether function has special prototype property. If not, prototype
// property will not be created when accessed (will return undefined),
// and construction from this function will not be allowed.
inline void set_function_with_prototype(bool value);
inline bool function_with_prototype();
// Tells whether the instance with this map should be ignored by the
// __proto__ accessor.
inline void set_is_hidden_prototype() {
set_bit_field(bit_field() | (1 << kIsHiddenPrototype));
}
inline bool is_hidden_prototype() {
return ((1 << kIsHiddenPrototype) & bit_field()) != 0;
}
// Records and queries whether the instance has a named interceptor.
inline void set_has_named_interceptor() {
set_bit_field(bit_field() | (1 << kHasNamedInterceptor));
}
inline bool has_named_interceptor() {
return ((1 << kHasNamedInterceptor) & bit_field()) != 0;
}
// Records and queries whether the instance has an indexed interceptor.
inline void set_has_indexed_interceptor() {
set_bit_field(bit_field() | (1 << kHasIndexedInterceptor));
}
inline bool has_indexed_interceptor() {
return ((1 << kHasIndexedInterceptor) & bit_field()) != 0;
}
// Tells whether the instance is undetectable.
// An undetectable object is a special class of JSObject: 'typeof' operator
// returns undefined, ToBoolean returns false. Otherwise it behaves like
// a normal JS object. It is useful for implementing undetectable
// document.all in Firefox & Safari.
// See https://bugzilla.mozilla.org/show_bug.cgi?id=248549.
inline void set_is_undetectable() {
set_bit_field(bit_field() | (1 << kIsUndetectable));
}
inline bool is_undetectable() {
return ((1 << kIsUndetectable) & bit_field()) != 0;
}
// Tells whether the instance has a call-as-function handler.
inline void set_has_instance_call_handler() {
set_bit_field(bit_field() | (1 << kHasInstanceCallHandler));
}
inline bool has_instance_call_handler() {
return ((1 << kHasInstanceCallHandler) & bit_field()) != 0;
}
inline void set_is_extensible(bool value);
inline bool is_extensible();
// Tells whether the instance has fast elements.
// Equivalent to instance->GetElementsKind() == FAST_ELEMENTS.
inline void set_has_fast_elements(bool value) {
if (value) {
set_bit_field2(bit_field2() | (1 << kHasFastElements));
} else {
set_bit_field2(bit_field2() & ~(1 << kHasFastElements));
}
}
inline bool has_fast_elements() {
return ((1 << kHasFastElements) & bit_field2()) != 0;
}
// Tells whether the map is attached to SharedFunctionInfo
// (for inobject slack tracking).
inline void set_attached_to_shared_function_info(bool value);
inline bool attached_to_shared_function_info();
// Tells whether the map is shared between objects that may have different
// behavior. If true, the map should never be modified, instead a clone
// should be created and modified.
inline void set_is_shared(bool value);
inline bool is_shared();
// Tells whether the instance needs security checks when accessing its
// properties.
inline void set_is_access_check_needed(bool access_check_needed);
inline bool is_access_check_needed();
// [prototype]: implicit prototype object.
DECL_ACCESSORS(prototype, Object)
// [constructor]: points back to the function responsible for this map.
DECL_ACCESSORS(constructor, Object)
inline JSFunction* unchecked_constructor();
// [instance descriptors]: describes the object.
DECL_ACCESSORS(instance_descriptors, DescriptorArray)
// [stub cache]: contains stubs compiled for this map.
DECL_ACCESSORS(code_cache, Object)
MUST_USE_RESULT MaybeObject* CopyDropDescriptors();
MUST_USE_RESULT MaybeObject* CopyNormalized(PropertyNormalizationMode mode,
NormalizedMapSharingMode sharing);
// Returns a copy of the map, with all transitions dropped from the
// instance descriptors.
MUST_USE_RESULT MaybeObject* CopyDropTransitions();
// Returns this map if it has the fast elements bit set, otherwise
// returns a copy of the map, with all transitions dropped from the
// descriptors and the fast elements bit set.
MUST_USE_RESULT inline MaybeObject* GetFastElementsMap();
// Returns this map if it has the fast elements bit cleared,
// otherwise returns a copy of the map, with all transitions dropped
// from the descriptors and the fast elements bit cleared.
MUST_USE_RESULT inline MaybeObject* GetSlowElementsMap();
// Returns the property index for name (only valid for FAST MODE).
int PropertyIndexFor(String* name);
// Returns the next free property index (only valid for FAST MODE).
int NextFreePropertyIndex();
// Returns the number of properties described in instance_descriptors.
int NumberOfDescribedProperties();
// Casting.
static inline Map* cast(Object* obj);
// Locate an accessor in the instance descriptor.
AccessorDescriptor* FindAccessor(String* name);
// Code cache operations.
// Clears the code cache.
inline void ClearCodeCache();
// Update code cache.
MUST_USE_RESULT MaybeObject* UpdateCodeCache(String* name, Code* code);
// Returns the found code or undefined if absent.
Object* FindInCodeCache(String* name, Code::Flags flags);
// Returns the non-negative index of the code object if it is in the
// cache and -1 otherwise.
int IndexInCodeCache(Object* name, Code* code);
// Removes a code object from the code cache at the given index.
void RemoveFromCodeCache(String* name, Code* code, int index);
// For every transition in this map, makes the transition's
// target's prototype pointer point back to this map.
// This is undone in MarkCompactCollector::ClearNonLiveTransitions().
void CreateBackPointers();
// Set all map transitions from this map to dead maps to null.
// Also, restore the original prototype on the targets of these
// transitions, so that we do not process this map again while
// following back pointers.
void ClearNonLiveTransitions(Object* real_prototype);
// Dispatched behavior.
#ifdef DEBUG
void MapPrint();
void MapVerify();
void SharedMapVerify();
#endif
inline int visitor_id();
inline void set_visitor_id(int visitor_id);
typedef void (*TraverseCallback)(Map* map, void* data);
void TraverseTransitionTree(TraverseCallback callback, void* data);
static const int kMaxPreAllocatedPropertyFields = 255;
// Layout description.
static const int kInstanceSizesOffset = HeapObject::kHeaderSize;
static const int kInstanceAttributesOffset = kInstanceSizesOffset + kIntSize;
static const int kPrototypeOffset = kInstanceAttributesOffset + kIntSize;
static const int kConstructorOffset = kPrototypeOffset + kPointerSize;
static const int kInstanceDescriptorsOffset =
kConstructorOffset + kPointerSize;
static const int kCodeCacheOffset = kInstanceDescriptorsOffset + kPointerSize;
static const int kPadStart = kCodeCacheOffset + kPointerSize;
static const int kSize = MAP_POINTER_ALIGN(kPadStart);
// Layout of pointer fields. Heap iteration code relies on them
// being continiously allocated.
static const int kPointerFieldsBeginOffset = Map::kPrototypeOffset;
static const int kPointerFieldsEndOffset =
Map::kCodeCacheOffset + kPointerSize;
// Byte offsets within kInstanceSizesOffset.
static const int kInstanceSizeOffset = kInstanceSizesOffset + 0;
static const int kInObjectPropertiesByte = 1;
static const int kInObjectPropertiesOffset =
kInstanceSizesOffset + kInObjectPropertiesByte;
static const int kPreAllocatedPropertyFieldsByte = 2;
static const int kPreAllocatedPropertyFieldsOffset =
kInstanceSizesOffset + kPreAllocatedPropertyFieldsByte;
static const int kVisitorIdByte = 3;
static const int kVisitorIdOffset = kInstanceSizesOffset + kVisitorIdByte;
// Byte offsets within kInstanceAttributesOffset attributes.
static const int kInstanceTypeOffset = kInstanceAttributesOffset + 0;
static const int kUnusedPropertyFieldsOffset = kInstanceAttributesOffset + 1;
static const int kBitFieldOffset = kInstanceAttributesOffset + 2;
static const int kBitField2Offset = kInstanceAttributesOffset + 3;
STATIC_CHECK(kInstanceTypeOffset == Internals::kMapInstanceTypeOffset);
// Bit positions for bit field.
static const int kUnused = 0; // To be used for marking recently used maps.
static const int kHasNonInstancePrototype = 1;
static const int kIsHiddenPrototype = 2;
static const int kHasNamedInterceptor = 3;
static const int kHasIndexedInterceptor = 4;
static const int kIsUndetectable = 5;
static const int kHasInstanceCallHandler = 6;
static const int kIsAccessCheckNeeded = 7;
// Bit positions for bit field 2
static const int kIsExtensible = 0;
static const int kFunctionWithPrototype = 1;
static const int kHasFastElements = 2;
static const int kStringWrapperSafeForDefaultValueOf = 3;
static const int kAttachedToSharedFunctionInfo = 4;
static const int kIsShared = 5;
// Layout of the default cache. It holds alternating name and code objects.
static const int kCodeCacheEntrySize = 2;
static const int kCodeCacheEntryNameOffset = 0;
static const int kCodeCacheEntryCodeOffset = 1;
typedef FixedBodyDescriptor<kPointerFieldsBeginOffset,
kPointerFieldsEndOffset,
kSize> BodyDescriptor;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Map);
};
// An abstract superclass, a marker class really, for simple structure classes.
// It doesn't carry much functionality but allows struct classes to me
// identified in the type system.
class Struct: public HeapObject {
public:
inline void InitializeBody(int object_size);
static inline Struct* cast(Object* that);
};
// Script describes a script which has been added to the VM.
class Script: public Struct {
public:
// Script types.
enum Type {
TYPE_NATIVE = 0,
TYPE_EXTENSION = 1,
TYPE_NORMAL = 2
};
// Script compilation types.
enum CompilationType {
COMPILATION_TYPE_HOST = 0,
COMPILATION_TYPE_EVAL = 1
};
// [source]: the script source.
DECL_ACCESSORS(source, Object)
// [name]: the script name.
DECL_ACCESSORS(name, Object)
// [id]: the script id.
DECL_ACCESSORS(id, Object)
// [line_offset]: script line offset in resource from where it was extracted.
DECL_ACCESSORS(line_offset, Smi)
// [column_offset]: script column offset in resource from where it was
// extracted.
DECL_ACCESSORS(column_offset, Smi)
// [data]: additional data associated with this script.
DECL_ACCESSORS(data, Object)
// [context_data]: context data for the context this script was compiled in.
DECL_ACCESSORS(context_data, Object)
// [wrapper]: the wrapper cache.
DECL_ACCESSORS(wrapper, Proxy)
// [type]: the script type.
DECL_ACCESSORS(type, Smi)
// [compilation]: how the the script was compiled.
DECL_ACCESSORS(compilation_type, Smi)
// [line_ends]: FixedArray of line ends positions.
DECL_ACCESSORS(line_ends, Object)
// [eval_from_shared]: for eval scripts the shared funcion info for the
// function from which eval was called.
DECL_ACCESSORS(eval_from_shared, Object)
// [eval_from_instructions_offset]: the instruction offset in the code for the
// function from which eval was called where eval was called.
DECL_ACCESSORS(eval_from_instructions_offset, Smi)
static inline Script* cast(Object* obj);
// If script source is an external string, check that the underlying
// resource is accessible. Otherwise, always return true.
inline bool HasValidSource();
#ifdef DEBUG
void ScriptPrint();
void ScriptVerify();
#endif
static const int kSourceOffset = HeapObject::kHeaderSize;
static const int kNameOffset = kSourceOffset + kPointerSize;
static const int kLineOffsetOffset = kNameOffset + kPointerSize;
static const int kColumnOffsetOffset = kLineOffsetOffset + kPointerSize;
static const int kDataOffset = kColumnOffsetOffset + kPointerSize;
static const int kContextOffset = kDataOffset + kPointerSize;
static const int kWrapperOffset = kContextOffset + kPointerSize;
static const int kTypeOffset = kWrapperOffset + kPointerSize;
static const int kCompilationTypeOffset = kTypeOffset + kPointerSize;
static const int kLineEndsOffset = kCompilationTypeOffset + kPointerSize;
static const int kIdOffset = kLineEndsOffset + kPointerSize;
static const int kEvalFromSharedOffset = kIdOffset + kPointerSize;
static const int kEvalFrominstructionsOffsetOffset =
kEvalFromSharedOffset + kPointerSize;
static const int kSize = kEvalFrominstructionsOffsetOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Script);
};
// SharedFunctionInfo describes the JSFunction information that can be
// shared by multiple instances of the function.
class SharedFunctionInfo: public HeapObject {
public:
// [name]: Function name.
DECL_ACCESSORS(name, Object)
// [code]: Function code.
DECL_ACCESSORS(code, Code)
// [scope_info]: Scope info.
DECL_ACCESSORS(scope_info, SerializedScopeInfo)
// [construct stub]: Code stub for constructing instances of this function.
DECL_ACCESSORS(construct_stub, Code)
inline Code* unchecked_code();
// Returns if this function has been compiled to native code yet.
inline bool is_compiled();
// [length]: The function length - usually the number of declared parameters.
// Use up to 2^30 parameters.
inline int length();
inline void set_length(int value);
// [formal parameter count]: The declared number of parameters.
inline int formal_parameter_count();
inline void set_formal_parameter_count(int value);
// Set the formal parameter count so the function code will be
// called without using argument adaptor frames.
inline void DontAdaptArguments();
// [expected_nof_properties]: Expected number of properties for the function.
inline int expected_nof_properties();
inline void set_expected_nof_properties(int value);
// Inobject slack tracking is the way to reclaim unused inobject space.
//
// The instance size is initially determined by adding some slack to
// expected_nof_properties (to allow for a few extra properties added
// after the constructor). There is no guarantee that the extra space
// will not be wasted.
//
// Here is the algorithm to reclaim the unused inobject space:
// - Detect the first constructor call for this SharedFunctionInfo.
// When it happens enter the "in progress" state: remember the
// constructor's initial_map and install a special construct stub that
// counts constructor calls.
// - While the tracking is in progress create objects filled with
// one_pointer_filler_map instead of undefined_value. This way they can be
// resized quickly and safely.
// - Once enough (kGenerousAllocationCount) objects have been created
// compute the 'slack' (traverse the map transition tree starting from the
// initial_map and find the lowest value of unused_property_fields).
// - Traverse the transition tree again and decrease the instance size
// of every map. Existing objects will resize automatically (they are
// filled with one_pointer_filler_map). All further allocations will
// use the adjusted instance size.
// - Decrease expected_nof_properties so that an allocations made from
// another context will use the adjusted instance size too.
// - Exit "in progress" state by clearing the reference to the initial_map
// and setting the regular construct stub (generic or inline).
//
// The above is the main event sequence. Some special cases are possible
// while the tracking is in progress:
//
// - GC occurs.
// Check if the initial_map is referenced by any live objects (except this
// SharedFunctionInfo). If it is, continue tracking as usual.
// If it is not, clear the reference and reset the tracking state. The
// tracking will be initiated again on the next constructor call.
//
// - The constructor is called from another context.
// Immediately complete the tracking, perform all the necessary changes
// to maps. This is necessary because there is no efficient way to track
// multiple initial_maps.
// Proceed to create an object in the current context (with the adjusted
// size).
//
// - A different constructor function sharing the same SharedFunctionInfo is
// called in the same context. This could be another closure in the same
// context, or the first function could have been disposed.
// This is handled the same way as the previous case.
//
// Important: inobject slack tracking is not attempted during the snapshot
// creation.
static const int kGenerousAllocationCount = 8;
// [construction_count]: Counter for constructor calls made during
// the tracking phase.
inline int construction_count();
inline void set_construction_count(int value);
// [initial_map]: initial map of the first function called as a constructor.
// Saved for the duration of the tracking phase.
// This is a weak link (GC resets it to undefined_value if no other live
// object reference this map).
DECL_ACCESSORS(initial_map, Object)
// True if the initial_map is not undefined and the countdown stub is
// installed.
inline bool IsInobjectSlackTrackingInProgress();
// Starts the tracking.
// Stores the initial map and installs the countdown stub.
// IsInobjectSlackTrackingInProgress is normally true after this call,
// except when tracking have not been started (e.g. the map has no unused
// properties or the snapshot is being built).
void StartInobjectSlackTracking(Map* map);
// Completes the tracking.
// IsInobjectSlackTrackingInProgress is false after this call.
void CompleteInobjectSlackTracking();
// Clears the initial_map before the GC marking phase to ensure the reference
// is weak. IsInobjectSlackTrackingInProgress is false after this call.
void DetachInitialMap();
// Restores the link to the initial map after the GC marking phase.
// IsInobjectSlackTrackingInProgress is true after this call.
void AttachInitialMap(Map* map);
// False if there are definitely no live objects created from this function.
// True if live objects _may_ exist (existence not guaranteed).
// May go back from true to false after GC.
inline bool live_objects_may_exist();
inline void set_live_objects_may_exist(bool value);
// [instance class name]: class name for instances.
DECL_ACCESSORS(instance_class_name, Object)
// [function data]: This field holds some additional data for function.
// Currently it either has FunctionTemplateInfo to make benefit the API
// or Smi identifying a custom call generator.
// In the long run we don't want all functions to have this field but
// we can fix that when we have a better model for storing hidden data
// on objects.
DECL_ACCESSORS(function_data, Object)
inline bool IsApiFunction();
inline FunctionTemplateInfo* get_api_func_data();
inline bool HasCustomCallGenerator();
inline int custom_call_generator_id();
// [script info]: Script from which the function originates.
DECL_ACCESSORS(script, Object)
// [num_literals]: Number of literals used by this function.
inline int num_literals();
inline void set_num_literals(int value);
// [start_position_and_type]: Field used to store both the source code
// position, whether or not the function is a function expression,
// and whether or not the function is a toplevel function. The two
// least significants bit indicates whether the function is an
// expression and the rest contains the source code position.
inline int start_position_and_type();
inline void set_start_position_and_type(int value);
// [debug info]: Debug information.
DECL_ACCESSORS(debug_info, Object)
// [inferred name]: Name inferred from variable or property
// assignment of this function. Used to facilitate debugging and
// profiling of JavaScript code written in OO style, where almost
// all functions are anonymous but are assigned to object
// properties.
DECL_ACCESSORS(inferred_name, String)
// The function's name if it is non-empty, otherwise the inferred name.
String* DebugName();
// Position of the 'function' token in the script source.
inline int function_token_position();
inline void set_function_token_position(int function_token_position);
// Position of this function in the script source.
inline int start_position();
inline void set_start_position(int start_position);
// End position of this function in the script source.
inline int end_position();
inline void set_end_position(int end_position);
// Is this function a function expression in the source code.
inline bool is_expression();
inline void set_is_expression(bool value);
// Is this function a top-level function (scripts, evals).
inline bool is_toplevel();
inline void set_is_toplevel(bool value);
// Bit field containing various information collected by the compiler to
// drive optimization.
inline int compiler_hints();
inline void set_compiler_hints(int value);
// Add information on assignments of the form this.x = ...;
void SetThisPropertyAssignmentsInfo(
bool has_only_simple_this_property_assignments,
FixedArray* this_property_assignments);
// Clear information on assignments of the form this.x = ...;
void ClearThisPropertyAssignmentsInfo();
// Indicate that this function only consists of assignments of the form
// this.x = y; where y is either a constant or refers to an argument.
inline bool has_only_simple_this_property_assignments();
inline bool try_full_codegen();
inline void set_try_full_codegen(bool flag);
// Indicates if this function can be lazy compiled.
// This is used to determine if we can safely flush code from a function
// when doing GC if we expect that the function will no longer be used.
inline bool allows_lazy_compilation();
inline void set_allows_lazy_compilation(bool flag);
// Indicates how many full GCs this function has survived with assigned
// code object. Used to determine when it is relatively safe to flush
// this code object and replace it with lazy compilation stub.
// Age is reset when GC notices that the code object is referenced
// from the stack or compilation cache.
inline int code_age();
inline void set_code_age(int age);
// Check whether a inlined constructor can be generated with the given
// prototype.
bool CanGenerateInlineConstructor(Object* prototype);
// Prevents further attempts to generate inline constructors.
// To be called if generation failed for any reason.
void ForbidInlineConstructor();
// For functions which only contains this property assignments this provides
// access to the names for the properties assigned.
DECL_ACCESSORS(this_property_assignments, Object)
inline int this_property_assignments_count();
inline void set_this_property_assignments_count(int value);
String* GetThisPropertyAssignmentName(int index);
bool IsThisPropertyAssignmentArgument(int index);
int GetThisPropertyAssignmentArgument(int index);
Object* GetThisPropertyAssignmentConstant(int index);
// [source code]: Source code for the function.
bool HasSourceCode();
Object* GetSourceCode();
// Calculate the instance size.
int CalculateInstanceSize();
// Calculate the number of in-object properties.
int CalculateInObjectProperties();
// Dispatched behavior.
// Set max_length to -1 for unlimited length.
void SourceCodePrint(StringStream* accumulator, int max_length);
#ifdef DEBUG
void SharedFunctionInfoPrint();
void SharedFunctionInfoVerify();
#endif
// Casting.
static inline SharedFunctionInfo* cast(Object* obj);
// Constants.
static const int kDontAdaptArgumentsSentinel = -1;
// Layout description.
// Pointer fields.
static const int kNameOffset = HeapObject::kHeaderSize;
static const int kCodeOffset = kNameOffset + kPointerSize;
static const int kScopeInfoOffset = kCodeOffset + kPointerSize;
static const int kConstructStubOffset = kScopeInfoOffset + kPointerSize;
static const int kInstanceClassNameOffset =
kConstructStubOffset + kPointerSize;
static const int kFunctionDataOffset =
kInstanceClassNameOffset + kPointerSize;
static const int kScriptOffset = kFunctionDataOffset + kPointerSize;
static const int kDebugInfoOffset = kScriptOffset + kPointerSize;
static const int kInferredNameOffset = kDebugInfoOffset + kPointerSize;
static const int kInitialMapOffset =
kInferredNameOffset + kPointerSize;
static const int kThisPropertyAssignmentsOffset =
kInitialMapOffset + kPointerSize;
#if V8_HOST_ARCH_32_BIT
// Smi fields.
static const int kLengthOffset =
kThisPropertyAssignmentsOffset + kPointerSize;
static const int kFormalParameterCountOffset = kLengthOffset + kPointerSize;
static const int kExpectedNofPropertiesOffset =
kFormalParameterCountOffset + kPointerSize;
static const int kNumLiteralsOffset =
kExpectedNofPropertiesOffset + kPointerSize;
static const int kStartPositionAndTypeOffset =
kNumLiteralsOffset + kPointerSize;
static const int kEndPositionOffset =
kStartPositionAndTypeOffset + kPointerSize;
static const int kFunctionTokenPositionOffset =
kEndPositionOffset + kPointerSize;
static const int kCompilerHintsOffset =
kFunctionTokenPositionOffset + kPointerSize;
static const int kThisPropertyAssignmentsCountOffset =
kCompilerHintsOffset + kPointerSize;
// Total size.
static const int kSize = kThisPropertyAssignmentsCountOffset + kPointerSize;
#else
// The only reason to use smi fields instead of int fields
// is to allow iteration without maps decoding during
// garbage collections.
// To avoid wasting space on 64-bit architectures we use
// the following trick: we group integer fields into pairs
// First integer in each pair is shifted left by 1.
// By doing this we guarantee that LSB of each kPointerSize aligned
// word is not set and thus this word cannot be treated as pointer
// to HeapObject during old space traversal.
static const int kLengthOffset =
kThisPropertyAssignmentsOffset + kPointerSize;
static const int kFormalParameterCountOffset =
kLengthOffset + kIntSize;
static const int kExpectedNofPropertiesOffset =
kFormalParameterCountOffset + kIntSize;
static const int kNumLiteralsOffset =
kExpectedNofPropertiesOffset + kIntSize;
static const int kEndPositionOffset =
kNumLiteralsOffset + kIntSize;
static const int kStartPositionAndTypeOffset =
kEndPositionOffset + kIntSize;
static const int kFunctionTokenPositionOffset =
kStartPositionAndTypeOffset + kIntSize;
static const int kCompilerHintsOffset =
kFunctionTokenPositionOffset + kIntSize;
static const int kThisPropertyAssignmentsCountOffset =
kCompilerHintsOffset + kIntSize;
// Total size.
static const int kSize = kThisPropertyAssignmentsCountOffset + kIntSize;
#endif
// The construction counter for inobject slack tracking is stored in the
// most significant byte of compiler_hints which is otherwise unused.
// Its offset depends on the endian-ness of the architecture.
#if __BYTE_ORDER == __LITTLE_ENDIAN
static const int kConstructionCountOffset = kCompilerHintsOffset + 3;
#elif __BYTE_ORDER == __BIG_ENDIAN
static const int kConstructionCountOffset = kCompilerHintsOffset + 0;
#else
#error Unknown byte ordering
#endif
static const int kAlignedSize = POINTER_SIZE_ALIGN(kSize);
typedef FixedBodyDescriptor<kNameOffset,
kThisPropertyAssignmentsOffset + kPointerSize,
kSize> BodyDescriptor;
private:
// Bit positions in start_position_and_type.
// The source code start position is in the 30 most significant bits of
// the start_position_and_type field.
static const int kIsExpressionBit = 0;
static const int kIsTopLevelBit = 1;
static const int kStartPositionShift = 2;
static const int kStartPositionMask = ~((1 << kStartPositionShift) - 1);
// Bit positions in compiler_hints.
static const int kHasOnlySimpleThisPropertyAssignments = 0;
static const int kTryFullCodegen = 1;
static const int kAllowLazyCompilation = 2;
static const int kLiveObjectsMayExist = 3;
static const int kCodeAgeShift = 4;
static const int kCodeAgeMask = 7;
DISALLOW_IMPLICIT_CONSTRUCTORS(SharedFunctionInfo);
};
// JSFunction describes JavaScript functions.
class JSFunction: public JSObject {
public:
// [prototype_or_initial_map]:
DECL_ACCESSORS(prototype_or_initial_map, Object)
// [shared_function_info]: The information about the function that
// can be shared by instances.
DECL_ACCESSORS(shared, SharedFunctionInfo)
inline SharedFunctionInfo* unchecked_shared();
// [context]: The context for this function.
inline Context* context();
inline Object* unchecked_context();
inline void set_context(Object* context);
// [code]: The generated code object for this function. Executed
// when the function is invoked, e.g. foo() or new foo(). See
// [[Call]] and [[Construct]] description in ECMA-262, section
// 8.6.2, page 27.
inline Code* code();
inline void set_code(Code* value);
inline Code* unchecked_code();
// Tells whether this function is builtin.
inline bool IsBuiltin();
// [literals]: Fixed array holding the materialized literals.
//
// If the function contains object, regexp or array literals, the
// literals array prefix contains the object, regexp, and array
// function to be used when creating these literals. This is
// necessary so that we do not dynamically lookup the object, regexp
// or array functions. Performing a dynamic lookup, we might end up
// using the functions from a new context that we should not have
// access to.
DECL_ACCESSORS(literals, FixedArray)
// The initial map for an object created by this constructor.
inline Map* initial_map();
inline void set_initial_map(Map* value);
inline bool has_initial_map();
// Get and set the prototype property on a JSFunction. If the
// function has an initial map the prototype is set on the initial
// map. Otherwise, the prototype is put in the initial map field
// until an initial map is needed.
inline bool has_prototype();
inline bool has_instance_prototype();
inline Object* prototype();
inline Object* instance_prototype();
Object* SetInstancePrototype(Object* value);
MUST_USE_RESULT MaybeObject* SetPrototype(Object* value);
// After prototype is removed, it will not be created when accessed, and
// [[Construct]] from this function will not be allowed.
Object* RemovePrototype();
inline bool should_have_prototype();
// Accessor for this function's initial map's [[class]]
// property. This is primarily used by ECMA native functions. This
// method sets the class_name field of this function's initial map
// to a given value. It creates an initial map if this function does
// not have one. Note that this method does not copy the initial map
// if it has one already, but simply replaces it with the new value.
// Instances created afterwards will have a map whose [[class]] is
// set to 'value', but there is no guarantees on instances created
// before.
Object* SetInstanceClassName(String* name);
// Returns if this function has been compiled to native code yet.
inline bool is_compiled();
// Casting.
static inline JSFunction* cast(Object* obj);
// Iterates the objects, including code objects indirectly referenced
// through pointers to the first instruction in the code object.
void JSFunctionIterateBody(int object_size, ObjectVisitor* v);
// Dispatched behavior.
#ifdef DEBUG
void JSFunctionPrint();
void JSFunctionVerify();
#endif
// Returns the number of allocated literals.
inline int NumberOfLiterals();
// Retrieve the global context from a function's literal array.
static Context* GlobalContextFromLiterals(FixedArray* literals);
// Layout descriptors.
static const int kCodeEntryOffset = JSObject::kHeaderSize;
static const int kPrototypeOrInitialMapOffset =
kCodeEntryOffset + kPointerSize;
static const int kSharedFunctionInfoOffset =
kPrototypeOrInitialMapOffset + kPointerSize;
static const int kContextOffset = kSharedFunctionInfoOffset + kPointerSize;
static const int kLiteralsOffset = kContextOffset + kPointerSize;
static const int kSize = kLiteralsOffset + kPointerSize;
// Layout of the literals array.
static const int kLiteralsPrefixSize = 1;
static const int kLiteralGlobalContextIndex = 0;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSFunction);
};
// JSGlobalProxy's prototype must be a JSGlobalObject or null,
// and the prototype is hidden. JSGlobalProxy always delegates
// property accesses to its prototype if the prototype is not null.
//
// A JSGlobalProxy can be reinitialized which will preserve its identity.
//
// Accessing a JSGlobalProxy requires security check.
class JSGlobalProxy : public JSObject {
public:
// [context]: the owner global context of this proxy object.
// It is null value if this object is not used by any context.
DECL_ACCESSORS(context, Object)
// Casting.
static inline JSGlobalProxy* cast(Object* obj);
// Dispatched behavior.
#ifdef DEBUG
void JSGlobalProxyPrint();
void JSGlobalProxyVerify();
#endif
// Layout description.
static const int kContextOffset = JSObject::kHeaderSize;
static const int kSize = kContextOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSGlobalProxy);
};
// Forward declaration.
class JSBuiltinsObject;
// Common super class for JavaScript global objects and the special
// builtins global objects.
class GlobalObject: public JSObject {
public:
// [builtins]: the object holding the runtime routines written in JS.
DECL_ACCESSORS(builtins, JSBuiltinsObject)
// [global context]: the global context corresponding to this global object.
DECL_ACCESSORS(global_context, Context)
// [global receiver]: the global receiver object of the context
DECL_ACCESSORS(global_receiver, JSObject)
// Retrieve the property cell used to store a property.
Object* GetPropertyCell(LookupResult* result);
// This is like GetProperty, but is used when you know the lookup won't fail
// by throwing an exception. This is for the debug and builtins global
// objects, where it is known which properties can be expected to be present
// on the object.
Object* GetPropertyNoExceptionThrown(String* key) {
Object* answer = GetProperty(key)->ToObjectUnchecked();
return answer;
}
// Ensure that the global object has a cell for the given property name.
MUST_USE_RESULT MaybeObject* EnsurePropertyCell(String* name);
// Casting.
static inline GlobalObject* cast(Object* obj);
// Layout description.
static const int kBuiltinsOffset = JSObject::kHeaderSize;
static const int kGlobalContextOffset = kBuiltinsOffset + kPointerSize;
static const int kGlobalReceiverOffset = kGlobalContextOffset + kPointerSize;
static const int kHeaderSize = kGlobalReceiverOffset + kPointerSize;
private:
friend class AGCCVersionRequiresThisClassToHaveAFriendSoHereItIs;
DISALLOW_IMPLICIT_CONSTRUCTORS(GlobalObject);
};
// JavaScript global object.
class JSGlobalObject: public GlobalObject {
public:
// Casting.
static inline JSGlobalObject* cast(Object* obj);
// Dispatched behavior.
#ifdef DEBUG
void JSGlobalObjectPrint();
void JSGlobalObjectVerify();
#endif
// Layout description.
static const int kSize = GlobalObject::kHeaderSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSGlobalObject);
};
// Builtins global object which holds the runtime routines written in
// JavaScript.
class JSBuiltinsObject: public GlobalObject {
public:
// Accessors for the runtime routines written in JavaScript.
inline Object* javascript_builtin(Builtins::JavaScript id);
inline void set_javascript_builtin(Builtins::JavaScript id, Object* value);
// Accessors for code of the runtime routines written in JavaScript.
inline Code* javascript_builtin_code(Builtins::JavaScript id);
inline void set_javascript_builtin_code(Builtins::JavaScript id, Code* value);
// Casting.
static inline JSBuiltinsObject* cast(Object* obj);
// Dispatched behavior.
#ifdef DEBUG
void JSBuiltinsObjectPrint();
void JSBuiltinsObjectVerify();
#endif
// Layout description. The size of the builtins object includes
// room for two pointers per runtime routine written in javascript
// (function and code object).
static const int kJSBuiltinsCount = Builtins::id_count;
static const int kJSBuiltinsOffset = GlobalObject::kHeaderSize;
static const int kJSBuiltinsCodeOffset =
GlobalObject::kHeaderSize + (kJSBuiltinsCount * kPointerSize);
static const int kSize =
kJSBuiltinsCodeOffset + (kJSBuiltinsCount * kPointerSize);
static int OffsetOfFunctionWithId(Builtins::JavaScript id) {
return kJSBuiltinsOffset + id * kPointerSize;
}
static int OffsetOfCodeWithId(Builtins::JavaScript id) {
return kJSBuiltinsCodeOffset + id * kPointerSize;
}
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSBuiltinsObject);
};
// Representation for JS Wrapper objects, String, Number, Boolean, Date, etc.
class JSValue: public JSObject {
public:
// [value]: the object being wrapped.
DECL_ACCESSORS(value, Object)
// Casting.
static inline JSValue* cast(Object* obj);
// Dispatched behavior.
#ifdef DEBUG
void JSValuePrint();
void JSValueVerify();
#endif
// Layout description.
static const int kValueOffset = JSObject::kHeaderSize;
static const int kSize = kValueOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSValue);
};
// Regular expressions
// The regular expression holds a single reference to a FixedArray in
// the kDataOffset field.
// The FixedArray contains the following data:
// - tag : type of regexp implementation (not compiled yet, atom or irregexp)
// - reference to the original source string
// - reference to the original flag string
// If it is an atom regexp
// - a reference to a literal string to search for
// If it is an irregexp regexp:
// - a reference to code for ASCII inputs (bytecode or compiled).
// - a reference to code for UC16 inputs (bytecode or compiled).
// - max number of registers used by irregexp implementations.
// - number of capture registers (output values) of the regexp.
class JSRegExp: public JSObject {
public:
// Meaning of Type:
// NOT_COMPILED: Initial value. No data has been stored in the JSRegExp yet.
// ATOM: A simple string to match against using an indexOf operation.
// IRREGEXP: Compiled with Irregexp.
// IRREGEXP_NATIVE: Compiled to native code with Irregexp.
enum Type { NOT_COMPILED, ATOM, IRREGEXP };
enum Flag { NONE = 0, GLOBAL = 1, IGNORE_CASE = 2, MULTILINE = 4 };
class Flags {
public:
explicit Flags(uint32_t value) : value_(value) { }
bool is_global() { return (value_ & GLOBAL) != 0; }
bool is_ignore_case() { return (value_ & IGNORE_CASE) != 0; }
bool is_multiline() { return (value_ & MULTILINE) != 0; }
uint32_t value() { return value_; }
private:
uint32_t value_;
};
DECL_ACCESSORS(data, Object)
inline Type TypeTag();
inline int CaptureCount();
inline Flags GetFlags();
inline String* Pattern();
inline Object* DataAt(int index);
// Set implementation data after the object has been prepared.
inline void SetDataAt(int index, Object* value);
static int code_index(bool is_ascii) {
if (is_ascii) {
return kIrregexpASCIICodeIndex;
} else {
return kIrregexpUC16CodeIndex;
}
}
static inline JSRegExp* cast(Object* obj);
// Dispatched behavior.
#ifdef DEBUG
void JSRegExpVerify();
#endif
static const int kDataOffset = JSObject::kHeaderSize;
static const int kSize = kDataOffset + kPointerSize;
// Indices in the data array.
static const int kTagIndex = 0;
static const int kSourceIndex = kTagIndex + 1;
static const int kFlagsIndex = kSourceIndex + 1;
static const int kDataIndex = kFlagsIndex + 1;
// The data fields are used in different ways depending on the
// value of the tag.
// Atom regexps (literal strings).
static const int kAtomPatternIndex = kDataIndex;
static const int kAtomDataSize = kAtomPatternIndex + 1;
// Irregexp compiled code or bytecode for ASCII. If compilation
// fails, this fields hold an exception object that should be
// thrown if the regexp is used again.
static const int kIrregexpASCIICodeIndex = kDataIndex;
// Irregexp compiled code or bytecode for UC16. If compilation
// fails, this fields hold an exception object that should be
// thrown if the regexp is used again.
static const int kIrregexpUC16CodeIndex = kDataIndex + 1;
// Maximal number of registers used by either ASCII or UC16.
// Only used to check that there is enough stack space
static const int kIrregexpMaxRegisterCountIndex = kDataIndex + 2;
// Number of captures in the compiled regexp.
static const int kIrregexpCaptureCountIndex = kDataIndex + 3;
static const int kIrregexpDataSize = kIrregexpCaptureCountIndex + 1;
// Offsets directly into the data fixed array.
static const int kDataTagOffset =
FixedArray::kHeaderSize + kTagIndex * kPointerSize;
static const int kDataAsciiCodeOffset =
FixedArray::kHeaderSize + kIrregexpASCIICodeIndex * kPointerSize;
static const int kDataUC16CodeOffset =
FixedArray::kHeaderSize + kIrregexpUC16CodeIndex * kPointerSize;
static const int kIrregexpCaptureCountOffset =
FixedArray::kHeaderSize + kIrregexpCaptureCountIndex * kPointerSize;
// In-object fields.
static const int kSourceFieldIndex = 0;
static const int kGlobalFieldIndex = 1;
static const int kIgnoreCaseFieldIndex = 2;
static const int kMultilineFieldIndex = 3;
static const int kLastIndexFieldIndex = 4;
static const int kInObjectFieldCount = 5;
};
class CompilationCacheShape {
public:
static inline bool IsMatch(HashTableKey* key, Object* value) {
return key->IsMatch(value);
}
static inline uint32_t Hash(HashTableKey* key) {
return key->Hash();
}
static inline uint32_t HashForObject(HashTableKey* key, Object* object) {
return key->HashForObject(object);
}
MUST_USE_RESULT static MaybeObject* AsObject(HashTableKey* key) {
return key->AsObject();
}
static const int kPrefixSize = 0;
static const int kEntrySize = 2;
};
class CompilationCacheTable: public HashTable<CompilationCacheShape,
HashTableKey*> {
public:
// Find cached value for a string key, otherwise return null.
Object* Lookup(String* src);
Object* LookupEval(String* src, Context* context);
Object* LookupRegExp(String* source, JSRegExp::Flags flags);
MaybeObject* Put(String* src, Object* value);
MaybeObject* PutEval(String* src, Context* context, Object* value);
MaybeObject* PutRegExp(String* src, JSRegExp::Flags flags, FixedArray* value);
static inline CompilationCacheTable* cast(Object* obj);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheTable);
};
class CodeCache: public Struct {
public:
DECL_ACCESSORS(default_cache, FixedArray)
DECL_ACCESSORS(normal_type_cache, Object)
// Add the code object to the cache.
MUST_USE_RESULT MaybeObject* Update(String* name, Code* code);
// Lookup code object in the cache. Returns code object if found and undefined
// if not.
Object* Lookup(String* name, Code::Flags flags);
// Get the internal index of a code object in the cache. Returns -1 if the
// code object is not in that cache. This index can be used to later call
// RemoveByIndex. The cache cannot be modified between a call to GetIndex and
// RemoveByIndex.
int GetIndex(Object* name, Code* code);
// Remove an object from the cache with the provided internal index.
void RemoveByIndex(Object* name, Code* code, int index);
static inline CodeCache* cast(Object* obj);
#ifdef DEBUG
void CodeCachePrint();
void CodeCacheVerify();
#endif
static const int kDefaultCacheOffset = HeapObject::kHeaderSize;
static const int kNormalTypeCacheOffset =
kDefaultCacheOffset + kPointerSize;
static const int kSize = kNormalTypeCacheOffset + kPointerSize;
private:
MUST_USE_RESULT MaybeObject* UpdateDefaultCache(String* name, Code* code);
MUST_USE_RESULT MaybeObject* UpdateNormalTypeCache(String* name, Code* code);
Object* LookupDefaultCache(String* name, Code::Flags flags);
Object* LookupNormalTypeCache(String* name, Code::Flags flags);
// Code cache layout of the default cache. Elements are alternating name and
// code objects for non normal load/store/call IC's.
static const int kCodeCacheEntrySize = 2;
static const int kCodeCacheEntryNameOffset = 0;
static const int kCodeCacheEntryCodeOffset = 1;
DISALLOW_IMPLICIT_CONSTRUCTORS(CodeCache);
};
class CodeCacheHashTableShape {
public:
static inline bool IsMatch(HashTableKey* key, Object* value) {
return key->IsMatch(value);
}
static inline uint32_t Hash(HashTableKey* key) {
return key->Hash();
}
static inline uint32_t HashForObject(HashTableKey* key, Object* object) {
return key->HashForObject(object);
}
MUST_USE_RESULT static MaybeObject* AsObject(HashTableKey* key) {
return key->AsObject();
}
static const int kPrefixSize = 0;
static const int kEntrySize = 2;
};
class CodeCacheHashTable: public HashTable<CodeCacheHashTableShape,
HashTableKey*> {
public:
Object* Lookup(String* name, Code::Flags flags);
MUST_USE_RESULT MaybeObject* Put(String* name, Code* code);
int GetIndex(String* name, Code::Flags flags);
void RemoveByIndex(int index);
static inline CodeCacheHashTable* cast(Object* obj);
// Initial size of the fixed array backing the hash table.
static const int kInitialSize = 64;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(CodeCacheHashTable);
};
enum AllowNullsFlag {ALLOW_NULLS, DISALLOW_NULLS};
enum RobustnessFlag {ROBUST_STRING_TRAVERSAL, FAST_STRING_TRAVERSAL};
class StringHasher {
public:
inline StringHasher(int length);
// Returns true if the hash of this string can be computed without
// looking at the contents.
inline bool has_trivial_hash();
// Add a character to the hash and update the array index calculation.
inline void AddCharacter(uc32 c);
// Adds a character to the hash but does not update the array index
// calculation. This can only be called when it has been verified
// that the input is not an array index.
inline void AddCharacterNoIndex(uc32 c);
// Returns the value to store in the hash field of a string with
// the given length and contents.
uint32_t GetHashField();
// Returns true if the characters seen so far make up a legal array
// index.
bool is_array_index() { return is_array_index_; }
bool is_valid() { return is_valid_; }
void invalidate() { is_valid_ = false; }
// Calculated hash value for a string consisting of 1 to
// String::kMaxArrayIndexSize digits with no leading zeros (except "0").
// value is represented decimal value.
static uint32_t MakeArrayIndexHash(uint32_t value, int length);
private:
uint32_t array_index() {
ASSERT(is_array_index());
return array_index_;
}
inline uint32_t GetHash();
int length_;
uint32_t raw_running_hash_;
uint32_t array_index_;
bool is_array_index_;
bool is_first_char_;
bool is_valid_;
friend class TwoCharHashTableKey;
};
// The characteristics of a string are stored in its map. Retrieving these
// few bits of information is moderately expensive, involving two memory
// loads where the second is dependent on the first. To improve efficiency
// the shape of the string is given its own class so that it can be retrieved
// once and used for several string operations. A StringShape is small enough
// to be passed by value and is immutable, but be aware that flattening a
// string can potentially alter its shape. Also be aware that a GC caused by
// something else can alter the shape of a string due to ConsString
// shortcutting. Keeping these restrictions in mind has proven to be error-
// prone and so we no longer put StringShapes in variables unless there is a
// concrete performance benefit at that particular point in the code.
class StringShape BASE_EMBEDDED {
public:
inline explicit StringShape(String* s);
inline explicit StringShape(Map* s);
inline explicit StringShape(InstanceType t);
inline bool IsSequential();
inline bool IsExternal();
inline bool IsCons();
inline bool IsExternalAscii();
inline bool IsExternalTwoByte();
inline bool IsSequentialAscii();
inline bool IsSequentialTwoByte();
inline bool IsSymbol();
inline StringRepresentationTag representation_tag();
inline uint32_t full_representation_tag();
inline uint32_t size_tag();
#ifdef DEBUG
inline uint32_t type() { return type_; }
inline void invalidate() { valid_ = false; }
inline bool valid() { return valid_; }
#else
inline void invalidate() { }
#endif
private:
uint32_t type_;
#ifdef DEBUG
inline void set_valid() { valid_ = true; }
bool valid_;
#else
inline void set_valid() { }
#endif
};
// The String abstract class captures JavaScript string values:
//
// Ecma-262:
// 4.3.16 String Value
// A string value is a member of the type String and is a finite
// ordered sequence of zero or more 16-bit unsigned integer values.
//
// All string values have a length field.
class String: public HeapObject {
public:
// Get and set the length of the string.
inline int length();
inline void set_length(int value);
// Get and set the hash field of the string.
inline uint32_t hash_field();
inline void set_hash_field(uint32_t value);
inline bool IsAsciiRepresentation();
inline bool IsTwoByteRepresentation();
// Returns whether this string has ascii chars, i.e. all of them can
// be ascii encoded. This might be the case even if the string is
// two-byte. Such strings may appear when the embedder prefers
// two-byte external representations even for ascii data.
//
// NOTE: this should be considered only a hint. False negatives are
// possible.
inline bool HasOnlyAsciiChars();
// Get and set individual two byte chars in the string.
inline void Set(int index, uint16_t value);
// Get individual two byte char in the string. Repeated calls
// to this method are not efficient unless the string is flat.
inline uint16_t Get(int index);
// Try to flatten the string. Checks first inline to see if it is
// necessary. Does nothing if the string is not a cons string.
// Flattening allocates a sequential string with the same data as
// the given string and mutates the cons string to a degenerate
// form, where the first component is the new sequential string and
// the second component is the empty string. If allocation fails,
// this function returns a failure. If flattening succeeds, this
// function returns the sequential string that is now the first
// component of the cons string.
//
// Degenerate cons strings are handled specially by the garbage
// collector (see IsShortcutCandidate).
//
// Use FlattenString from Handles.cc to flatten even in case an
// allocation failure happens.
inline MaybeObject* TryFlatten(PretenureFlag pretenure = NOT_TENURED);
// Convenience function. Has exactly the same behavior as
// TryFlatten(), except in the case of failure returns the original
// string.
inline String* TryFlattenGetString(PretenureFlag pretenure = NOT_TENURED);
Vector<const char> ToAsciiVector();
Vector<const uc16> ToUC16Vector();
// Mark the string as an undetectable object. It only applies to
// ascii and two byte string types.
bool MarkAsUndetectable();
// Return a substring.
MUST_USE_RESULT MaybeObject* SubString(int from,
int to,
PretenureFlag pretenure = NOT_TENURED);
// String equality operations.
inline bool Equals(String* other);
bool IsEqualTo(Vector<const char> str);
// Return a UTF8 representation of the string. The string is null
// terminated but may optionally contain nulls. Length is returned
// in length_output if length_output is not a null pointer The string
// should be nearly flat, otherwise the performance of this method may
// be very slow (quadratic in the length). Setting robustness_flag to
// ROBUST_STRING_TRAVERSAL invokes behaviour that is robust This means it
// handles unexpected data without causing assert failures and it does not
// do any heap allocations. This is useful when printing stack traces.
SmartPointer<char> ToCString(AllowNullsFlag allow_nulls,
RobustnessFlag robustness_flag,
int offset,
int length,
int* length_output = 0);
SmartPointer<char> ToCString(
AllowNullsFlag allow_nulls = DISALLOW_NULLS,
RobustnessFlag robustness_flag = FAST_STRING_TRAVERSAL,
int* length_output = 0);
int Utf8Length();
// Return a 16 bit Unicode representation of the string.
// The string should be nearly flat, otherwise the performance of
// of this method may be very bad. Setting robustness_flag to
// ROBUST_STRING_TRAVERSAL invokes behaviour that is robust This means it
// handles unexpected data without causing assert failures and it does not
// do any heap allocations. This is useful when printing stack traces.
SmartPointer<uc16> ToWideCString(
RobustnessFlag robustness_flag = FAST_STRING_TRAVERSAL);
// Tells whether the hash code has been computed.
inline bool HasHashCode();
// Returns a hash value used for the property table
inline uint32_t Hash();
static uint32_t ComputeHashField(unibrow::CharacterStream* buffer,
int length);
static bool ComputeArrayIndex(unibrow::CharacterStream* buffer,
uint32_t* index,
int length);
// Externalization.
bool MakeExternal(v8::String::ExternalStringResource* resource);
bool MakeExternal(v8::String::ExternalAsciiStringResource* resource);
// Conversion.
inline bool AsArrayIndex(uint32_t* index);
// Casting.
static inline String* cast(Object* obj);
void PrintOn(FILE* out);
// For use during stack traces. Performs rudimentary sanity check.
bool LooksValid();
// Dispatched behavior.
void StringShortPrint(StringStream* accumulator);
#ifdef DEBUG
void StringPrint();
void StringVerify();
#endif
inline bool IsFlat();
// Layout description.
static const int kLengthOffset = HeapObject::kHeaderSize;
static const int kHashFieldOffset = kLengthOffset + kPointerSize;
static const int kSize = kHashFieldOffset + kPointerSize;
// Maximum number of characters to consider when trying to convert a string
// value into an array index.
static const int kMaxArrayIndexSize = 10;
// Max ascii char code.
static const int kMaxAsciiCharCode = unibrow::Utf8::kMaxOneByteChar;
static const unsigned kMaxAsciiCharCodeU = unibrow::Utf8::kMaxOneByteChar;
static const int kMaxUC16CharCode = 0xffff;
// Minimum length for a cons string.
static const int kMinNonFlatLength = 13;
// Mask constant for checking if a string has a computed hash code
// and if it is an array index. The least significant bit indicates
// whether a hash code has been computed. If the hash code has been
// computed the 2nd bit tells whether the string can be used as an
// array index.
static const int kHashNotComputedMask = 1;
static const int kIsNotArrayIndexMask = 1 << 1;
static const int kNofHashBitFields = 2;
// Shift constant retrieving hash code from hash field.
static const int kHashShift = kNofHashBitFields;
// Array index strings this short can keep their index in the hash
// field.
static const int kMaxCachedArrayIndexLength = 7;
// For strings which are array indexes the hash value has the string length
// mixed into the hash, mainly to avoid a hash value of zero which would be
// the case for the string '0'. 24 bits are used for the array index value.
static const int kArrayIndexValueBits = 24;
static const int kArrayIndexLengthBits =
kBitsPerInt - kArrayIndexValueBits - kNofHashBitFields;
STATIC_CHECK((kArrayIndexLengthBits > 0));
STATIC_CHECK(kMaxArrayIndexSize < (1 << kArrayIndexLengthBits));
static const int kArrayIndexHashLengthShift =
kArrayIndexValueBits + kNofHashBitFields;
static const int kArrayIndexHashMask = (1 << kArrayIndexHashLengthShift) - 1;
static const int kArrayIndexValueMask =
((1 << kArrayIndexValueBits) - 1) << kHashShift;
// Check that kMaxCachedArrayIndexLength + 1 is a power of two so we
// could use a mask to test if the length of string is less than or equal to
// kMaxCachedArrayIndexLength.
STATIC_CHECK(IS_POWER_OF_TWO(kMaxCachedArrayIndexLength + 1));
static const int kContainsCachedArrayIndexMask =
(~kMaxCachedArrayIndexLength << kArrayIndexHashLengthShift) |
kIsNotArrayIndexMask;
// Value of empty hash field indicating that the hash is not computed.
static const int kEmptyHashField =
kIsNotArrayIndexMask | kHashNotComputedMask;
// Value of hash field containing computed hash equal to zero.
static const int kZeroHash = kIsNotArrayIndexMask;
// Maximal string length.
static const int kMaxLength = (1 << (32 - 2)) - 1;
// Max length for computing hash. For strings longer than this limit the
// string length is used as the hash value.
static const int kMaxHashCalcLength = 16383;
// Limit for truncation in short printing.
static const int kMaxShortPrintLength = 1024;
// Support for regular expressions.
const uc16* GetTwoByteData();
const uc16* GetTwoByteData(unsigned start);
// Support for StringInputBuffer
static const unibrow::byte* ReadBlock(String* input,
unibrow::byte* util_buffer,
unsigned capacity,
unsigned* remaining,
unsigned* offset);
static const unibrow::byte* ReadBlock(String** input,
unibrow::byte* util_buffer,
unsigned capacity,
unsigned* remaining,
unsigned* offset);
// Helper function for flattening strings.
template <typename sinkchar>
static void WriteToFlat(String* source,
sinkchar* sink,
int from,
int to);
protected:
class ReadBlockBuffer {
public:
ReadBlockBuffer(unibrow::byte* util_buffer_,
unsigned cursor_,
unsigned capacity_,
unsigned remaining_) :
util_buffer(util_buffer_),
cursor(cursor_),
capacity(capacity_),
remaining(remaining_) {
}
unibrow::byte* util_buffer;
unsigned cursor;
unsigned capacity;
unsigned remaining;
};
static inline const unibrow::byte* ReadBlock(String* input,
ReadBlockBuffer* buffer,
unsigned* offset,
unsigned max_chars);
static void ReadBlockIntoBuffer(String* input,
ReadBlockBuffer* buffer,
unsigned* offset_ptr,
unsigned max_chars);
private:
// Try to flatten the top level ConsString that is hiding behind this
// string. This is a no-op unless the string is a ConsString. Flatten
// mutates the ConsString and might return a failure.
MUST_USE_RESULT MaybeObject* SlowTryFlatten(PretenureFlag pretenure);
static inline bool IsHashFieldComputed(uint32_t field);
// Slow case of String::Equals. This implementation works on any strings
// but it is most efficient on strings that are almost flat.
bool SlowEquals(String* other);
// Slow case of AsArrayIndex.
bool SlowAsArrayIndex(uint32_t* index);
// Compute and set the hash code.
uint32_t ComputeAndSetHash();
DISALLOW_IMPLICIT_CONSTRUCTORS(String);
};
// The SeqString abstract class captures sequential string values.
class SeqString: public String {
public:
// Casting.
static inline SeqString* cast(Object* obj);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(SeqString);
};
// The AsciiString class captures sequential ascii string objects.
// Each character in the AsciiString is an ascii character.
class SeqAsciiString: public SeqString {
public:
static const bool kHasAsciiEncoding = true;
// Dispatched behavior.
inline uint16_t SeqAsciiStringGet(int index);
inline void SeqAsciiStringSet(int index, uint16_t value);
// Get the address of the characters in this string.
inline Address GetCharsAddress();
inline char* GetChars();
// Casting
static inline SeqAsciiString* cast(Object* obj);
// Garbage collection support. This method is called by the
// garbage collector to compute the actual size of an AsciiString
// instance.
inline int SeqAsciiStringSize(InstanceType instance_type);
// Computes the size for an AsciiString instance of a given length.
static int SizeFor(int length) {
return OBJECT_POINTER_ALIGN(kHeaderSize + length * kCharSize);
}
// Layout description.
static const int kHeaderSize = String::kSize;
static const int kAlignedSize = POINTER_SIZE_ALIGN(kHeaderSize);
// Maximal memory usage for a single sequential ASCII string.
static const int kMaxSize = 512 * MB;
// Maximal length of a single sequential ASCII string.
// Q.v. String::kMaxLength which is the maximal size of concatenated strings.
static const int kMaxLength = (kMaxSize - kHeaderSize);
// Support for StringInputBuffer.
inline void SeqAsciiStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
unsigned* offset,
unsigned chars);
inline const unibrow::byte* SeqAsciiStringReadBlock(unsigned* remaining,
unsigned* offset,
unsigned chars);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(SeqAsciiString);
};
// The TwoByteString class captures sequential unicode string objects.
// Each character in the TwoByteString is a two-byte uint16_t.
class SeqTwoByteString: public SeqString {
public:
static const bool kHasAsciiEncoding = false;
// Dispatched behavior.
inline uint16_t SeqTwoByteStringGet(int index);
inline void SeqTwoByteStringSet(int index, uint16_t value);
// Get the address of the characters in this string.
inline Address GetCharsAddress();
inline uc16* GetChars();
// For regexp code.
const uint16_t* SeqTwoByteStringGetData(unsigned start);
// Casting
static inline SeqTwoByteString* cast(Object* obj);
// Garbage collection support. This method is called by the
// garbage collector to compute the actual size of a TwoByteString
// instance.
inline int SeqTwoByteStringSize(InstanceType instance_type);
// Computes the size for a TwoByteString instance of a given length.
static int SizeFor(int length) {
return OBJECT_POINTER_ALIGN(kHeaderSize + length * kShortSize);
}
// Layout description.
static const int kHeaderSize = String::kSize;
static const int kAlignedSize = POINTER_SIZE_ALIGN(kHeaderSize);
// Maximal memory usage for a single sequential two-byte string.
static const int kMaxSize = 512 * MB;
// Maximal length of a single sequential two-byte string.
// Q.v. String::kMaxLength which is the maximal size of concatenated strings.
static const int kMaxLength = (kMaxSize - kHeaderSize) / sizeof(uint16_t);
// Support for StringInputBuffer.
inline void SeqTwoByteStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
unsigned* offset_ptr,
unsigned chars);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(SeqTwoByteString);
};
// The ConsString class describes string values built by using the
// addition operator on strings. A ConsString is a pair where the
// first and second components are pointers to other string values.
// One or both components of a ConsString can be pointers to other
// ConsStrings, creating a binary tree of ConsStrings where the leaves
// are non-ConsString string values. The string value represented by
// a ConsString can be obtained by concatenating the leaf string
// values in a left-to-right depth-first traversal of the tree.
class ConsString: public String {
public:
// First string of the cons cell.
inline String* first();
// Doesn't check that the result is a string, even in debug mode. This is
// useful during GC where the mark bits confuse the checks.
inline Object* unchecked_first();
inline void set_first(String* first,
WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
// Second string of the cons cell.
inline String* second();
// Doesn't check that the result is a string, even in debug mode. This is
// useful during GC where the mark bits confuse the checks.
inline Object* unchecked_second();
inline void set_second(String* second,
WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
// Dispatched behavior.
uint16_t ConsStringGet(int index);
// Casting.
static inline ConsString* cast(Object* obj);
// Layout description.
static const int kFirstOffset = POINTER_SIZE_ALIGN(String::kSize);
static const int kSecondOffset = kFirstOffset + kPointerSize;
static const int kSize = kSecondOffset + kPointerSize;
// Support for StringInputBuffer.
inline const unibrow::byte* ConsStringReadBlock(ReadBlockBuffer* buffer,
unsigned* offset_ptr,
unsigned chars);
inline void ConsStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
unsigned* offset_ptr,
unsigned chars);
// Minimum length for a cons string.
static const int kMinLength = 13;
typedef FixedBodyDescriptor<kFirstOffset, kSecondOffset + kPointerSize, kSize>
BodyDescriptor;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ConsString);
};
// The ExternalString class describes string values that are backed by
// a string resource that lies outside the V8 heap. ExternalStrings
// consist of the length field common to all strings, a pointer to the
// external resource. It is important to ensure (externally) that the
// resource is not deallocated while the ExternalString is live in the
// V8 heap.
//
// The API expects that all ExternalStrings are created through the
// API. Therefore, ExternalStrings should not be used internally.
class ExternalString: public String {
public:
// Casting
static inline ExternalString* cast(Object* obj);
// Layout description.
static const int kResourceOffset = POINTER_SIZE_ALIGN(String::kSize);
static const int kSize = kResourceOffset + kPointerSize;
STATIC_CHECK(kResourceOffset == Internals::kStringResourceOffset);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalString);
};
// The ExternalAsciiString class is an external string backed by an
// ASCII string.
class ExternalAsciiString: public ExternalString {
public:
static const bool kHasAsciiEncoding = true;
typedef v8::String::ExternalAsciiStringResource Resource;
// The underlying resource.
inline Resource* resource();
inline void set_resource(Resource* buffer);
// Dispatched behavior.
uint16_t ExternalAsciiStringGet(int index);
// Casting.
static inline ExternalAsciiString* cast(Object* obj);
// Garbage collection support.
inline void ExternalAsciiStringIterateBody(ObjectVisitor* v);
template<typename StaticVisitor>
inline void ExternalAsciiStringIterateBody();
// Support for StringInputBuffer.
const unibrow::byte* ExternalAsciiStringReadBlock(unsigned* remaining,
unsigned* offset,
unsigned chars);
inline void ExternalAsciiStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
unsigned* offset,
unsigned chars);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalAsciiString);
};
// The ExternalTwoByteString class is an external string backed by a UTF-16
// encoded string.
class ExternalTwoByteString: public ExternalString {
public:
static const bool kHasAsciiEncoding = false;
typedef v8::String::ExternalStringResource Resource;
// The underlying string resource.
inline Resource* resource();
inline void set_resource(Resource* buffer);
// Dispatched behavior.
uint16_t ExternalTwoByteStringGet(int index);
// For regexp code.
const uint16_t* ExternalTwoByteStringGetData(unsigned start);
// Casting.
static inline ExternalTwoByteString* cast(Object* obj);
// Garbage collection support.
inline void ExternalTwoByteStringIterateBody(ObjectVisitor* v);
template<typename StaticVisitor>
inline void ExternalTwoByteStringIterateBody();
// Support for StringInputBuffer.
void ExternalTwoByteStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
unsigned* offset_ptr,
unsigned chars);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalTwoByteString);
};
// 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 BASE_EMBEDDED {
public:
inline Relocatable() : prev_(top_) { top_ = this; }
virtual ~Relocatable() {
ASSERT_EQ(top_, this);
top_ = prev_;
}
virtual void IterateInstance(ObjectVisitor* v) { }
virtual void PostGarbageCollection() { }
static void PostGarbageCollectionProcessing();
static int ArchiveSpacePerThread();
static char* ArchiveState(char* to);
static char* RestoreState(char* from);
static void Iterate(ObjectVisitor* v);
static void Iterate(ObjectVisitor* v, Relocatable* top);
static char* Iterate(ObjectVisitor* v, char* t);
private:
static Relocatable* top_;
Relocatable* prev_;
};
// A flat string reader provides random access to the contents of a
// string independent of the character width of the string. The handle
// must be valid as long as the reader is being used.
class FlatStringReader : public Relocatable {
public:
explicit FlatStringReader(Handle<String> str);
explicit FlatStringReader(Vector<const char> input);
void PostGarbageCollection();
inline uc32 Get(int index);
int length() { return length_; }
private:
String** str_;
bool is_ascii_;
int length_;
const void* start_;
};
// Note that StringInputBuffers are not valid across a GC! To fix this
// it would have to store a String Handle instead of a String* and
// AsciiStringReadBlock would have to be modified to use memcpy.
//
// StringInputBuffer is able to traverse any string regardless of how
// deeply nested a sequence of ConsStrings it is made of. However,
// performance will be better if deep strings are flattened before they
// are traversed. Since flattening requires memory allocation this is
// not always desirable, however (esp. in debugging situations).
class StringInputBuffer: public unibrow::InputBuffer<String, String*, 1024> {
public:
virtual void Seek(unsigned pos);
inline StringInputBuffer(): unibrow::InputBuffer<String, String*, 1024>() {}
inline StringInputBuffer(String* backing):
unibrow::InputBuffer<String, String*, 1024>(backing) {}
};
class SafeStringInputBuffer
: public unibrow::InputBuffer<String, String**, 256> {
public:
virtual void Seek(unsigned pos);
inline SafeStringInputBuffer()
: unibrow::InputBuffer<String, String**, 256>() {}
inline SafeStringInputBuffer(String** backing)
: unibrow::InputBuffer<String, String**, 256>(backing) {}
};
template <typename T>
class VectorIterator {
public:
VectorIterator(T* d, int l) : data_(Vector<const T>(d, l)), index_(0) { }
explicit VectorIterator(Vector<const T> data) : data_(data), index_(0) { }
T GetNext() { return data_[index_++]; }
bool has_more() { return index_ < data_.length(); }
private:
Vector<const T> data_;
int index_;
};
// The Oddball describes objects null, undefined, true, and false.
class Oddball: public HeapObject {
public:
// [to_string]: Cached to_string computed at startup.
DECL_ACCESSORS(to_string, String)
// [to_number]: Cached to_number computed at startup.
DECL_ACCESSORS(to_number, Object)
// Casting.
static inline Oddball* cast(Object* obj);
// Dispatched behavior.
#ifdef DEBUG
void OddballVerify();
#endif
// Initialize the fields.
MUST_USE_RESULT MaybeObject* Initialize(const char* to_string,
Object* to_number);
// Layout description.
static const int kToStringOffset = HeapObject::kHeaderSize;
static const int kToNumberOffset = kToStringOffset + kPointerSize;
static const int kSize = kToNumberOffset + kPointerSize;
typedef FixedBodyDescriptor<kToStringOffset,
kToNumberOffset + kPointerSize,
kSize> BodyDescriptor;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Oddball);
};
class JSGlobalPropertyCell: public HeapObject {
public:
// [value]: value of the global property.
DECL_ACCESSORS(value, Object)
// Casting.
static inline JSGlobalPropertyCell* cast(Object* obj);
#ifdef DEBUG
void JSGlobalPropertyCellVerify();
void JSGlobalPropertyCellPrint();
#endif
// Layout description.
static const int kValueOffset = HeapObject::kHeaderSize;
static const int kSize = kValueOffset + kPointerSize;
typedef FixedBodyDescriptor<kValueOffset,
kValueOffset + kPointerSize,
kSize> BodyDescriptor;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSGlobalPropertyCell);
};
// Proxy describes objects pointing from JavaScript to C structures.
// Since they cannot contain references to JS HeapObjects they can be
// placed in old_data_space.
class Proxy: public HeapObject {
public:
// [proxy]: field containing the address.
inline Address proxy();
inline void set_proxy(Address value);
// Casting.
static inline Proxy* cast(Object* obj);
// Dispatched behavior.
inline void ProxyIterateBody(ObjectVisitor* v);
template<typename StaticVisitor>
inline void ProxyIterateBody();
#ifdef DEBUG
void ProxyPrint();
void ProxyVerify();
#endif
// Layout description.
static const int kProxyOffset = HeapObject::kHeaderSize;
static const int kSize = kProxyOffset + kPointerSize;
STATIC_CHECK(kProxyOffset == Internals::kProxyProxyOffset);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Proxy);
};
// The JSArray describes JavaScript Arrays
// Such an array can be in one of two modes:
// - fast, backing storage is a FixedArray and length <= elements.length();
// Please note: push and pop can be used to grow and shrink the array.
// - slow, backing storage is a HashTable with numbers as keys.
class JSArray: public JSObject {
public:
// [length]: The length property.
DECL_ACCESSORS(length, Object)
// Overload the length setter to skip write barrier when the length
// is set to a smi. This matches the set function on FixedArray.
inline void set_length(Smi* length);
MUST_USE_RESULT MaybeObject* JSArrayUpdateLengthFromIndex(uint32_t index,
Object* value);
// Initialize the array with the given capacity. The function may
// fail due to out-of-memory situations, but only if the requested
// capacity is non-zero.
MUST_USE_RESULT MaybeObject* Initialize(int capacity);
// Set the content of the array to the content of storage.
inline void SetContent(FixedArray* storage);
// Casting.
static inline JSArray* cast(Object* obj);
// Uses handles. Ensures that the fixed array backing the JSArray has at
// least the stated size.
inline void EnsureSize(int minimum_size_of_backing_fixed_array);
// Dispatched behavior.
#ifdef DEBUG
void JSArrayPrint();
void JSArrayVerify();
#endif
// Number of element slots to pre-allocate for an empty array.
static const int kPreallocatedArrayElements = 4;
// Layout description.
static const int kLengthOffset = JSObject::kHeaderSize;
static const int kSize = kLengthOffset + kPointerSize;
private:
// Expand the fixed array backing of a fast-case JSArray to at least
// the requested size.
void Expand(int minimum_size_of_backing_fixed_array);
DISALLOW_IMPLICIT_CONSTRUCTORS(JSArray);
};
// JSRegExpResult is just a JSArray with a specific initial map.
// This initial map adds in-object properties for "index" and "input"
// properties, as assigned by RegExp.prototype.exec, which allows
// faster creation of RegExp exec results.
// This class just holds constants used when creating the result.
// After creation the result must be treated as a JSArray in all regards.
class JSRegExpResult: public JSArray {
public:
// Offsets of object fields.
static const int kIndexOffset = JSArray::kSize;
static const int kInputOffset = kIndexOffset + kPointerSize;
static const int kSize = kInputOffset + kPointerSize;
// Indices of in-object properties.
static const int kIndexIndex = 0;
static const int kInputIndex = 1;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSRegExpResult);
};
// An accessor must have a getter, but can have no setter.
//
// When setting a property, V8 searches accessors in prototypes.
// If an accessor was found and it does not have a setter,
// the request is ignored.
//
// If the accessor in the prototype has the READ_ONLY property attribute, then
// a new value is added to the local object when the property is set.
// This shadows the accessor in the prototype.
class AccessorInfo: public Struct {
public:
DECL_ACCESSORS(getter, Object)
DECL_ACCESSORS(setter, Object)
DECL_ACCESSORS(data, Object)
DECL_ACCESSORS(name, Object)
DECL_ACCESSORS(flag, Smi)
DECL_ACCESSORS(load_stub_cache, Object)
inline bool all_can_read();
inline void set_all_can_read(bool value);
inline bool all_can_write();
inline void set_all_can_write(bool value);
inline bool prohibits_overwriting();
inline void set_prohibits_overwriting(bool value);
inline PropertyAttributes property_attributes();
inline void set_property_attributes(PropertyAttributes attributes);
static inline AccessorInfo* cast(Object* obj);
#ifdef DEBUG
void AccessorInfoPrint();
void AccessorInfoVerify();
#endif
static const int kGetterOffset = HeapObject::kHeaderSize;
static const int kSetterOffset = kGetterOffset + kPointerSize;
static const int kDataOffset = kSetterOffset + kPointerSize;
static const int kNameOffset = kDataOffset + kPointerSize;
static const int kFlagOffset = kNameOffset + kPointerSize;
static const int kLoadStubCacheOffset = kFlagOffset + kPointerSize;
static const int kSize = kLoadStubCacheOffset + kPointerSize;
private:
// Bit positions in flag.
static const int kAllCanReadBit = 0;
static const int kAllCanWriteBit = 1;
static const int kProhibitsOverwritingBit = 2;
class AttributesField: public BitField<PropertyAttributes, 3, 3> {};
DISALLOW_IMPLICIT_CONSTRUCTORS(AccessorInfo);
};
class AccessCheckInfo: public Struct {
public:
DECL_ACCESSORS(named_callback, Object)
DECL_ACCESSORS(indexed_callback, Object)
DECL_ACCESSORS(data, Object)
static inline AccessCheckInfo* cast(Object* obj);
#ifdef DEBUG
void AccessCheckInfoPrint();
void AccessCheckInfoVerify();
#endif
static const int kNamedCallbackOffset = HeapObject::kHeaderSize;
static const int kIndexedCallbackOffset = kNamedCallbackOffset + kPointerSize;
static const int kDataOffset = kIndexedCallbackOffset + kPointerSize;
static const int kSize = kDataOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(AccessCheckInfo);
};
class InterceptorInfo: public Struct {
public:
DECL_ACCESSORS(getter, Object)
DECL_ACCESSORS(setter, Object)
DECL_ACCESSORS(query, Object)
DECL_ACCESSORS(deleter, Object)
DECL_ACCESSORS(enumerator, Object)
DECL_ACCESSORS(data, Object)
static inline InterceptorInfo* cast(Object* obj);
#ifdef DEBUG
void InterceptorInfoPrint();
void InterceptorInfoVerify();
#endif
static const int kGetterOffset = HeapObject::kHeaderSize;
static const int kSetterOffset = kGetterOffset + kPointerSize;
static const int kQueryOffset = kSetterOffset + kPointerSize;
static const int kDeleterOffset = kQueryOffset + kPointerSize;
static const int kEnumeratorOffset = kDeleterOffset + kPointerSize;
static const int kDataOffset = kEnumeratorOffset + kPointerSize;
static const int kSize = kDataOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(InterceptorInfo);
};
class CallHandlerInfo: public Struct {
public:
DECL_ACCESSORS(callback, Object)
DECL_ACCESSORS(data, Object)
DECL_ACCESSORS(call_stub_cache, Object)
static inline CallHandlerInfo* cast(Object* obj);
#ifdef DEBUG
void CallHandlerInfoPrint();
void CallHandlerInfoVerify();
#endif
static const int kCallbackOffset = HeapObject::kHeaderSize;
static const int kDataOffset = kCallbackOffset + kPointerSize;
static const int kCallStubCacheOffset = kDataOffset + kPointerSize;
static const int kSize = kCallStubCacheOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(CallHandlerInfo);
};
class TemplateInfo: public Struct {
public:
DECL_ACCESSORS(tag, Object)
DECL_ACCESSORS(property_list, Object)
#ifdef DEBUG
void TemplateInfoVerify();
#endif
static const int kTagOffset = HeapObject::kHeaderSize;
static const int kPropertyListOffset = kTagOffset + kPointerSize;
static const int kHeaderSize = kPropertyListOffset + kPointerSize;
protected:
friend class AGCCVersionRequiresThisClassToHaveAFriendSoHereItIs;
DISALLOW_IMPLICIT_CONSTRUCTORS(TemplateInfo);
};
class FunctionTemplateInfo: public TemplateInfo {
public:
DECL_ACCESSORS(serial_number, Object)
DECL_ACCESSORS(call_code, Object)
DECL_ACCESSORS(property_accessors, Object)
DECL_ACCESSORS(prototype_template, Object)
DECL_ACCESSORS(parent_template, Object)
DECL_ACCESSORS(named_property_handler, Object)
DECL_ACCESSORS(indexed_property_handler, Object)
DECL_ACCESSORS(instance_template, Object)
DECL_ACCESSORS(class_name, Object)
DECL_ACCESSORS(signature, Object)
DECL_ACCESSORS(instance_call_handler, Object)
DECL_ACCESSORS(access_check_info, Object)
DECL_ACCESSORS(flag, Smi)
// Following properties use flag bits.
DECL_BOOLEAN_ACCESSORS(hidden_prototype)
DECL_BOOLEAN_ACCESSORS(undetectable)
// If the bit is set, object instances created by this function
// requires access check.
DECL_BOOLEAN_ACCESSORS(needs_access_check)
static inline FunctionTemplateInfo* cast(Object* obj);
#ifdef DEBUG
void FunctionTemplateInfoPrint();
void FunctionTemplateInfoVerify();
#endif
static const int kSerialNumberOffset = TemplateInfo::kHeaderSize;
static const int kCallCodeOffset = kSerialNumberOffset + kPointerSize;
static const int kPropertyAccessorsOffset = kCallCodeOffset + kPointerSize;
static const int kPrototypeTemplateOffset =
kPropertyAccessorsOffset + kPointerSize;
static const int kParentTemplateOffset =
kPrototypeTemplateOffset + kPointerSize;
static const int kNamedPropertyHandlerOffset =
kParentTemplateOffset + kPointerSize;
static const int kIndexedPropertyHandlerOffset =
kNamedPropertyHandlerOffset + kPointerSize;
static const int kInstanceTemplateOffset =
kIndexedPropertyHandlerOffset + kPointerSize;
static const int kClassNameOffset = kInstanceTemplateOffset + kPointerSize;
static const int kSignatureOffset = kClassNameOffset + kPointerSize;
static const int kInstanceCallHandlerOffset = kSignatureOffset + kPointerSize;
static const int kAccessCheckInfoOffset =
kInstanceCallHandlerOffset + kPointerSize;
static const int kFlagOffset = kAccessCheckInfoOffset + kPointerSize;
static const int kSize = kFlagOffset + kPointerSize;
private:
// Bit position in the flag, from least significant bit position.
static const int kHiddenPrototypeBit = 0;
static const int kUndetectableBit = 1;
static const int kNeedsAccessCheckBit = 2;
DISALLOW_IMPLICIT_CONSTRUCTORS(FunctionTemplateInfo);
};
class ObjectTemplateInfo: public TemplateInfo {
public:
DECL_ACCESSORS(constructor, Object)
DECL_ACCESSORS(internal_field_count, Object)
static inline ObjectTemplateInfo* cast(Object* obj);
#ifdef DEBUG
void ObjectTemplateInfoPrint();
void ObjectTemplateInfoVerify();
#endif
static const int kConstructorOffset = TemplateInfo::kHeaderSize;
static const int kInternalFieldCountOffset =
kConstructorOffset + kPointerSize;
static const int kSize = kInternalFieldCountOffset + kPointerSize;
};
class SignatureInfo: public Struct {
public:
DECL_ACCESSORS(receiver, Object)
DECL_ACCESSORS(args, Object)
static inline SignatureInfo* cast(Object* obj);
#ifdef DEBUG
void SignatureInfoPrint();
void SignatureInfoVerify();
#endif
static const int kReceiverOffset = Struct::kHeaderSize;
static const int kArgsOffset = kReceiverOffset + kPointerSize;
static const int kSize = kArgsOffset + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(SignatureInfo);
};
class TypeSwitchInfo: public Struct {
public:
DECL_ACCESSORS(types, Object)
static inline TypeSwitchInfo* cast(Object* obj);
#ifdef DEBUG
void TypeSwitchInfoPrint();
void TypeSwitchInfoVerify();
#endif
static const int kTypesOffset = Struct::kHeaderSize;
static const int kSize = kTypesOffset + kPointerSize;
};
#ifdef ENABLE_DEBUGGER_SUPPORT
// The DebugInfo class holds additional information for a function being
// debugged.
class DebugInfo: public Struct {
public:
// The shared function info for the source being debugged.
DECL_ACCESSORS(shared, SharedFunctionInfo)
// Code object for the original code.
DECL_ACCESSORS(original_code, Code)
// Code object for the patched code. This code object is the code object
// currently active for the function.
DECL_ACCESSORS(code, Code)
// Fixed array holding status information for each active break point.
DECL_ACCESSORS(break_points, FixedArray)
// Check if there is a break point at a code position.
bool HasBreakPoint(int code_position);
// Get the break point info object for a code position.
Object* GetBreakPointInfo(int code_position);
// Clear a break point.
static void ClearBreakPoint(Handle<DebugInfo> debug_info,
int code_position,
Handle<Object> break_point_object);
// Set a break point.
static void SetBreakPoint(Handle<DebugInfo> debug_info, int code_position,
int source_position, int statement_position,
Handle<Object> break_point_object);
// Get the break point objects for a code position.
Object* GetBreakPointObjects(int code_position);
// Find the break point info holding this break point object.
static Object* FindBreakPointInfo(Handle<DebugInfo> debug_info,
Handle<Object> break_point_object);
// Get the number of break points for this function.
int GetBreakPointCount();
static inline DebugInfo* cast(Object* obj);
#ifdef DEBUG
void DebugInfoPrint();
void DebugInfoVerify();
#endif
static const int kSharedFunctionInfoIndex = Struct::kHeaderSize;
static const int kOriginalCodeIndex = kSharedFunctionInfoIndex + kPointerSize;
static const int kPatchedCodeIndex = kOriginalCodeIndex + kPointerSize;
static const int kActiveBreakPointsCountIndex =
kPatchedCodeIndex + kPointerSize;
static const int kBreakPointsStateIndex =
kActiveBreakPointsCountIndex + kPointerSize;
static const int kSize = kBreakPointsStateIndex + kPointerSize;
private:
static const int kNoBreakPointInfo = -1;
// Lookup the index in the break_points array for a code position.
int GetBreakPointInfoIndex(int code_position);
DISALLOW_IMPLICIT_CONSTRUCTORS(DebugInfo);
};
// The BreakPointInfo class holds information for break points set in a
// function. The DebugInfo object holds a BreakPointInfo object for each code
// position with one or more break points.
class BreakPointInfo: public Struct {
public:
// The position in the code for the break point.
DECL_ACCESSORS(code_position, Smi)
// The position in the source for the break position.
DECL_ACCESSORS(source_position, Smi)
// The position in the source for the last statement before this break
// position.
DECL_ACCESSORS(statement_position, Smi)
// List of related JavaScript break points.
DECL_ACCESSORS(break_point_objects, Object)
// Removes a break point.
static void ClearBreakPoint(Handle<BreakPointInfo> info,
Handle<Object> break_point_object);
// Set a break point.
static void SetBreakPoint(Handle<BreakPointInfo> info,
Handle<Object> break_point_object);
// Check if break point info has this break point object.
static bool HasBreakPointObject(Handle<BreakPointInfo> info,
Handle<Object> break_point_object);
// Get the number of break points for this code position.
int GetBreakPointCount();
static inline BreakPointInfo* cast(Object* obj);
#ifdef DEBUG
void BreakPointInfoPrint();
void BreakPointInfoVerify();
#endif
static const int kCodePositionIndex = Struct::kHeaderSize;
static const int kSourcePositionIndex = kCodePositionIndex + kPointerSize;
static const int kStatementPositionIndex =
kSourcePositionIndex + kPointerSize;
static const int kBreakPointObjectsIndex =
kStatementPositionIndex + kPointerSize;
static const int kSize = kBreakPointObjectsIndex + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(BreakPointInfo);
};
#endif // ENABLE_DEBUGGER_SUPPORT
#undef DECL_BOOLEAN_ACCESSORS
#undef DECL_ACCESSORS
// Abstract base class for visiting, and optionally modifying, the
// pointers contained in Objects. Used in GC and serialization/deserialization.
class ObjectVisitor BASE_EMBEDDED {
public:
virtual ~ObjectVisitor() {}
// Visits a contiguous arrays of pointers in the half-open range
// [start, end). Any or all of the values may be modified on return.
virtual void VisitPointers(Object** start, Object** end) = 0;
// To allow lazy clearing of inline caches the visitor has
// a rich interface for iterating over Code objects..
// Visits a code target in the instruction stream.
virtual void VisitCodeTarget(RelocInfo* rinfo);
// Visits a code entry in a JS function.
virtual void VisitCodeEntry(Address entry_address);
// Visits a runtime entry in the instruction stream.
virtual void VisitRuntimeEntry(RelocInfo* rinfo) {}
// Visits the resource of an ASCII or two-byte string.
virtual void VisitExternalAsciiString(
v8::String::ExternalAsciiStringResource** resource) {}
virtual void VisitExternalTwoByteString(
v8::String::ExternalStringResource** resource) {}
// Visits a debug call target in the instruction stream.
virtual void VisitDebugTarget(RelocInfo* rinfo);
// Handy shorthand for visiting a single pointer.
virtual void VisitPointer(Object** p) { VisitPointers(p, p + 1); }
// Visits a contiguous arrays of external references (references to the C++
// heap) in the half-open range [start, end). Any or all of the values
// may be modified on return.
virtual void VisitExternalReferences(Address* start, Address* end) {}
inline void VisitExternalReference(Address* p) {
VisitExternalReferences(p, p + 1);
}
#ifdef DEBUG
// Intended for serialization/deserialization checking: insert, or
// check for the presence of, a tag at this position in the stream.
virtual void Synchronize(const char* tag) {}
#else
inline void Synchronize(const char* tag) {}
#endif
};
class StructBodyDescriptor : public
FlexibleBodyDescriptor<HeapObject::kHeaderSize> {
public:
static inline int SizeOf(Map* map, HeapObject* object) {
return map->instance_size();
}
};
// BooleanBit is a helper class for setting and getting a bit in an
// integer or Smi.
class BooleanBit : public AllStatic {
public:
static inline bool get(Smi* smi, int bit_position) {
return get(smi->value(), bit_position);
}
static inline bool get(int value, int bit_position) {
return (value & (1 << bit_position)) != 0;
}
static inline Smi* set(Smi* smi, int bit_position, bool v) {
return Smi::FromInt(set(smi->value(), bit_position, v));
}
static inline int set(int value, int bit_position, bool v) {
if (v) {
value |= (1 << bit_position);
} else {
value &= ~(1 << bit_position);
}
return value;
}
};
} } // namespace v8::internal
#endif // V8_OBJECTS_H_