blob: 1464bb51d42ce2c270699d45209aeba5fec7b0d0 [file] [log] [blame]
* Copyright (C) 1999-2001 Harri Porten (
* Copyright (C) 2001 Peter Kelly (
* Copyright (C) 2003-2017 Apple Inc. All rights reserved.
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Library General Public License for more details.
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
#pragma once
#include "CallData.h"
#include "CellState.h"
#include "ConstructData.h"
#include "EnumerationMode.h"
#include "Heap.h"
#include "HeapCell.h"
#include "IndexingType.h"
#include "JSLock.h"
#include "JSTypeInfo.h"
#include "SlotVisitor.h"
#include "TypedArrayType.h"
#include "WriteBarrier.h"
#include <wtf/Noncopyable.h>
namespace JSC {
class CopyVisitor;
class GCDeferralContext;
class ExecState;
class Identifier;
class JSArrayBufferView;
class JSDestructibleObject;
class JSGlobalObject;
class LLIntOffsetsExtractor;
class PropertyDescriptor;
class PropertyNameArray;
class Structure;
template<typename T> void* allocateCell(Heap&);
template<typename T> void* allocateCell(Heap&, size_t);
template<typename T> void* allocateCell(Heap&, GCDeferralContext*);
template<typename T> void* allocateCell(Heap&, GCDeferralContext*, size_t);
protected: \
static JS_EXPORTDATA const ::JSC::ClassInfo s_info; \
public: \
static constexpr const ::JSC::ClassInfo* info() { return &s_info; }
#define DECLARE_INFO \
protected: \
static const ::JSC::ClassInfo s_info; \
public: \
static constexpr const ::JSC::ClassInfo* info() { return &s_info; }
class JSCell : public HeapCell {
friend class JSValue;
friend class MarkedBlock;
template<typename T> friend void* allocateCell(Heap&);
template<typename T> friend void* allocateCell(Heap&, size_t);
template<typename T> friend void* allocateCell(Heap&, GCDeferralContext*);
template<typename T> friend void* allocateCell(Heap&, GCDeferralContext*, size_t);
static const unsigned StructureFlags = 0;
static const bool needsDestruction = false;
// Don't call this directly. Call JSC::subspaceFor<Type>(vm) instead.
// FIXME: Refer to Subspace by reference.
template<typename CellType>
static Subspace* subspaceFor(VM&);
static JSCell* seenMultipleCalleeObjects() { return bitwise_cast<JSCell*>(static_cast<uintptr_t>(1)); }
enum CreatingEarlyCellTag { CreatingEarlyCell };
JSCell(VM&, Structure*);
JS_EXPORT_PRIVATE static void destroy(JSCell*);
// Querying the type.
bool isString() const;
bool isSymbol() const;
bool isObject() const;
bool isAnyWasmCallee(VM&) const;
bool isGetterSetter() const;
bool isCustomGetterSetter() const;
bool isProxy() const;
bool inherits(VM&, const ClassInfo*) const;
bool isAPIValueWrapper() const;
// Each cell has a built-in lock. Currently it's simply available for use if you need it. It's
// a full-blown WTF::Lock. Note that this lock is currently used in JSArray and that lock's
// ordering with the Structure lock is that the Structure lock must be acquired first.
void lock();
bool tryLock();
void unlock();
bool isLocked() const;
JSType type() const;
IndexingType indexingTypeAndMisc() const;
IndexingType indexingType() const;
StructureID structureID() const { return m_structureID; }
Structure* structure() const;
Structure* structure(VM&) const;
void setStructure(VM&, Structure*);
void setStructureIDDirectly(StructureID id) { m_structureID = id; }
void clearStructure() { m_structureID = 0; }
TypeInfo::InlineTypeFlags inlineTypeFlags() const { return m_flags; }
const char* className(VM&) const;
// Extracting the value.
JS_EXPORT_PRIVATE bool getString(ExecState*, String&) const;
JS_EXPORT_PRIVATE String getString(ExecState*) const; // null string if not a string
JS_EXPORT_PRIVATE JSObject* getObject(); // NULL if not an object
const JSObject* getObject() const; // NULL if not an object
// Returns information about how to call/construct this cell as a function/constructor. May tell
// you that the cell is not callable or constructor (default is that it's not either). If it
// says that the function is callable, and the TypeOfShouldCallGetCallData type flag is set, and
// this is an object, then typeof will return "function" instead of "object". These methods
// cannot change their minds and must be thread-safe. They are sometimes called from compiler
// threads.
JS_EXPORT_PRIVATE static CallType getCallData(JSCell*, CallData&);
JS_EXPORT_PRIVATE static ConstructType getConstructData(JSCell*, ConstructData&);
// Basic conversions.
JS_EXPORT_PRIVATE JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
bool getPrimitiveNumber(ExecState*, double& number, JSValue&) const;
bool toBoolean(ExecState*) const;
TriState pureToBoolean() const;
JS_EXPORT_PRIVATE double toNumber(ExecState*) const;
JSObject* toObject(ExecState*, JSGlobalObject*) const;
void dump(PrintStream&) const;
JS_EXPORT_PRIVATE static void dumpToStream(const JSCell*, PrintStream&);
size_t estimatedSizeInBytes() const;
JS_EXPORT_PRIVATE static size_t estimatedSize(JSCell*);
static void visitChildren(JSCell*, SlotVisitor&);
static void visitOutputConstraints(JSCell*, SlotVisitor&);
JS_EXPORT_PRIVATE static void heapSnapshot(JSCell*, HeapSnapshotBuilder&);
// Object operations, with the toObject operation included.
const ClassInfo* classInfo(VM&) const;
const MethodTable* methodTable() const;
const MethodTable* methodTable(VM&) const;
static bool put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
static bool putByIndex(JSCell*, ExecState*, unsigned propertyName, JSValue, bool shouldThrow);
static bool deleteProperty(JSCell*, ExecState*, PropertyName);
static bool deletePropertyByIndex(JSCell*, ExecState*, unsigned propertyName);
static JSValue toThis(JSCell*, ExecState*, ECMAMode);
static bool canUseFastGetOwnProperty(const Structure&);
JSValue fastGetOwnProperty(VM&, Structure&, PropertyName);
// The recommended idiom for using cellState() is to switch on it or perform an == comparison on it
// directly. We deliberately avoid helpers for this, because we want transparency about how the various
// CellState values influences our various algorithms.
CellState cellState() const { return m_cellState; }
void setCellState(CellState data) const { const_cast<JSCell*>(this)->m_cellState = data; }
bool atomicCompareExchangeCellStateWeakRelaxed(CellState oldState, CellState newState)
return WTF::atomicCompareExchangeWeakRelaxed(&m_cellState, oldState, newState);
CellState atomicCompareExchangeCellStateStrong(CellState oldState, CellState newState)
return WTF::atomicCompareExchangeStrong(&m_cellState, oldState, newState);
static ptrdiff_t structureIDOffset()
return OBJECT_OFFSETOF(JSCell, m_structureID);
static ptrdiff_t typeInfoFlagsOffset()
return OBJECT_OFFSETOF(JSCell, m_flags);
static ptrdiff_t typeInfoTypeOffset()
return OBJECT_OFFSETOF(JSCell, m_type);
// DO NOT store to this field. Always use a CAS loop, since some bits are flipped using CAS
// from other threads due to the internal lock. One exception: you don't need the CAS if the
// object has not escaped yet.
static ptrdiff_t indexingTypeAndMiscOffset()
return OBJECT_OFFSETOF(JSCell, m_indexingTypeAndMisc);
static ptrdiff_t cellStateOffset()
return OBJECT_OFFSETOF(JSCell, m_cellState);
void callDestructor(VM&);
static const TypedArrayType TypedArrayStorageType = NotTypedArray;
void finishCreation(VM&);
void finishCreation(VM&, Structure*, CreatingEarlyCellTag);
// Dummy implementations of override-able static functions for classes to put in their MethodTable
static JSValue defaultValue(const JSObject*, ExecState*, PreferredPrimitiveType);
static NO_RETURN_DUE_TO_CRASH void getOwnPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
static NO_RETURN_DUE_TO_CRASH void getOwnNonIndexPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
static NO_RETURN_DUE_TO_CRASH void getPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
static uint32_t getEnumerableLength(ExecState*, JSObject*);
static NO_RETURN_DUE_TO_CRASH void getStructurePropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
static NO_RETURN_DUE_TO_CRASH void getGenericPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
static NO_RETURN_DUE_TO_CRASH bool preventExtensions(JSObject*, ExecState*);
static NO_RETURN_DUE_TO_CRASH bool isExtensible(JSObject*, ExecState*);
static NO_RETURN_DUE_TO_CRASH bool setPrototype(JSObject*, ExecState*, JSValue, bool);
static NO_RETURN_DUE_TO_CRASH JSValue getPrototype(JSObject*, ExecState*);
static String className(const JSObject*);
static String toStringName(const JSObject*, ExecState*);
JS_EXPORT_PRIVATE static bool customHasInstance(JSObject*, ExecState*, JSValue);
static bool defineOwnProperty(JSObject*, ExecState*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
static bool getOwnPropertySlot(JSObject*, ExecState*, PropertyName, PropertySlot&);
static bool getOwnPropertySlotByIndex(JSObject*, ExecState*, unsigned propertyName, PropertySlot&);
JS_EXPORT_PRIVATE static ArrayBuffer* slowDownAndWasteMemory(JSArrayBufferView*);
JS_EXPORT_PRIVATE static RefPtr<ArrayBufferView> getTypedArrayImpl(JSArrayBufferView*);
friend class LLIntOffsetsExtractor;
JS_EXPORT_PRIVATE JSObject* toObjectSlow(ExecState*, JSGlobalObject*) const;
StructureID m_structureID;
IndexingType m_indexingTypeAndMisc; // DO NOT store to this field. Always CAS.
JSType m_type;
TypeInfo::InlineTypeFlags m_flags;
CellState m_cellState;
template<typename To, typename From>
inline To jsCast(From* from)
ASSERT_WITH_SECURITY_IMPLICATION(!from || from->JSCell::inherits(*from->JSCell::vm(), std::remove_pointer<To>::type::info()));
return static_cast<To>(from);
template<typename To>
inline To jsCast(JSValue from)
ASSERT_WITH_SECURITY_IMPLICATION(from.isCell() && from.asCell()->JSCell::inherits(*from.asCell()->vm(), std::remove_pointer<To>::type::info()));
return static_cast<To>(from.asCell());
template<typename To, typename From>
inline To jsDynamicCast(VM& vm, From* from)
if (LIKELY(from->JSCell::inherits(vm, std::remove_pointer<To>::type::info())))
return static_cast<To>(from);
return nullptr;
template<typename To>
inline To jsDynamicCast(VM& vm, JSValue from)
if (LIKELY(from.isCell() && from.asCell()->inherits(vm, std::remove_pointer<To>::type::info())))
return static_cast<To>(from.asCell());
return nullptr;
// FIXME: Refer to Subspace by reference.
template<typename Type>
inline Subspace* subspaceFor(VM& vm)
return Type::template subspaceFor<Type>(vm);
} // namespace JSC