blob: 8c505786e0ce6f8a47cc3df50342c187d229c937 [file] [log] [blame]
/*
* Copyright (C) 2008, 2009, 2012 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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 Structure_h
#define Structure_h
#include "ClassInfo.h"
#include "IndexingType.h"
#include "JSCell.h"
#include "JSType.h"
#include "JSValue.h"
#include "PropertyMapHashTable.h"
#include "PropertyName.h"
#include "PropertyNameArray.h"
#include "Protect.h"
#include "StructureTransitionTable.h"
#include "JSTypeInfo.h"
#include "Watchpoint.h"
#include "Weak.h"
#include <wtf/PassOwnPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/text/StringImpl.h>
namespace JSC {
class LLIntOffsetsExtractor;
class PropertyNameArray;
class PropertyNameArrayData;
class StructureChain;
class SlotVisitor;
class JSString;
// The out-of-line property storage capacity to use when first allocating out-of-line
// storage. Note that all objects start out without having any out-of-line storage;
// this comes into play only on the first property store that exhausts inline storage.
static const unsigned initialOutOfLineCapacity = 4;
// The factor by which to grow out-of-line storage when it is exhausted, after the
// initial allocation.
static const unsigned outOfLineGrowthFactor = 2;
class Structure : public JSCell {
public:
friend class StructureTransitionTable;
typedef JSCell Base;
static Structure* create(JSGlobalData&, JSGlobalObject*, JSValue prototype, const TypeInfo&, const ClassInfo*, IndexingType = NonArray, PropertyOffset inlineCapacity = 0);
protected:
void finishCreation(JSGlobalData& globalData)
{
Base::finishCreation(globalData);
ASSERT(m_prototype);
ASSERT(m_prototype.isObject() || m_prototype.isNull());
}
void finishCreation(JSGlobalData& globalData, CreatingEarlyCellTag)
{
Base::finishCreation(globalData, this, CreatingEarlyCell);
ASSERT(m_prototype);
ASSERT(m_prototype.isNull());
ASSERT(!globalData.structureStructure);
}
public:
static void dumpStatistics();
JS_EXPORT_PRIVATE static Structure* addPropertyTransition(JSGlobalData&, Structure*, PropertyName, unsigned attributes, JSCell* specificValue, PropertyOffset&);
JS_EXPORT_PRIVATE static Structure* addPropertyTransitionToExistingStructure(Structure*, PropertyName, unsigned attributes, JSCell* specificValue, PropertyOffset&);
static Structure* removePropertyTransition(JSGlobalData&, Structure*, PropertyName, PropertyOffset&);
JS_EXPORT_PRIVATE static Structure* changePrototypeTransition(JSGlobalData&, Structure*, JSValue prototype);
JS_EXPORT_PRIVATE static Structure* despecifyFunctionTransition(JSGlobalData&, Structure*, PropertyName);
static Structure* attributeChangeTransition(JSGlobalData&, Structure*, PropertyName, unsigned attributes);
static Structure* toCacheableDictionaryTransition(JSGlobalData&, Structure*);
static Structure* toUncacheableDictionaryTransition(JSGlobalData&, Structure*);
static Structure* sealTransition(JSGlobalData&, Structure*);
static Structure* freezeTransition(JSGlobalData&, Structure*);
static Structure* preventExtensionsTransition(JSGlobalData&, Structure*);
static Structure* nonPropertyTransition(JSGlobalData&, Structure*, NonPropertyTransition);
bool isSealed(JSGlobalData&);
bool isFrozen(JSGlobalData&);
bool isExtensible() const { return !m_preventExtensions; }
bool didTransition() const { return m_didTransition; }
bool putWillGrowOutOfLineStorage()
{
ASSERT(outOfLineCapacity() >= outOfLineSize());
if (!m_propertyTable) {
unsigned currentSize = numberOfOutOfLineSlotsForLastOffset(m_offset);
ASSERT(outOfLineCapacity() >= currentSize);
return currentSize == outOfLineCapacity();
}
ASSERT(totalStorageCapacity() >= m_propertyTable->propertyStorageSize());
if (m_propertyTable->hasDeletedOffset())
return false;
ASSERT(totalStorageCapacity() >= m_propertyTable->size());
return m_propertyTable->size() == totalStorageCapacity();
}
JS_EXPORT_PRIVATE size_t suggestedNewOutOfLineStorageCapacity();
Structure* flattenDictionaryStructure(JSGlobalData&, JSObject*);
static const bool needsDestruction = true;
static const bool hasImmortalStructure = true;
static void destroy(JSCell*);
// These should be used with caution.
JS_EXPORT_PRIVATE PropertyOffset addPropertyWithoutTransition(JSGlobalData&, PropertyName, unsigned attributes, JSCell* specificValue);
PropertyOffset removePropertyWithoutTransition(JSGlobalData&, PropertyName);
void setPrototypeWithoutTransition(JSGlobalData& globalData, JSValue prototype) { m_prototype.set(globalData, this, prototype); }
bool isDictionary() const { return m_dictionaryKind != NoneDictionaryKind; }
bool isUncacheableDictionary() const { return m_dictionaryKind == UncachedDictionaryKind; }
bool propertyAccessesAreCacheable() { return m_dictionaryKind != UncachedDictionaryKind && !typeInfo().prohibitsPropertyCaching(); }
// Type accessors.
const TypeInfo& typeInfo() const { ASSERT(structure()->classInfo() == s_classinfo()); return m_typeInfo; }
bool isObject() const { return typeInfo().isObject(); }
IndexingType indexingType() const { return m_indexingType & AllArrayTypes; }
IndexingType indexingTypeIncludingHistory() const { return m_indexingType; }
bool mayInterceptIndexedAccesses() const
{
return !!(indexingTypeIncludingHistory() & MayHaveIndexedAccessors);
}
bool anyObjectInChainMayInterceptIndexedAccesses() const;
bool needsSlowPutIndexing() const;
NonPropertyTransition suggestedArrayStorageTransition() const;
JSGlobalObject* globalObject() const { return m_globalObject.get(); }
void setGlobalObject(JSGlobalData& globalData, JSGlobalObject* globalObject) { m_globalObject.set(globalData, this, globalObject); }
JSValue storedPrototype() const { return m_prototype.get(); }
JSValue prototypeForLookup(ExecState*) const;
JSValue prototypeForLookup(JSGlobalObject*) const;
JSValue prototypeForLookup(CodeBlock*) const;
StructureChain* prototypeChain(JSGlobalData&, JSGlobalObject*) const;
StructureChain* prototypeChain(ExecState*) const;
static void visitChildren(JSCell*, SlotVisitor&);
// Will just the prototype chain intercept this property access?
bool prototypeChainMayInterceptStoreTo(JSGlobalData&, PropertyName);
bool transitionDidInvolveSpecificValue() const { return !!m_specificValueInPrevious; }
Structure* previousID() const
{
ASSERT(structure()->classInfo() == s_classinfo());
return m_previous.get();
}
bool transitivelyTransitionedFrom(Structure* structureToFind);
void growOutOfLineCapacity();
unsigned outOfLineCapacity() const
{
ASSERT(structure()->classInfo() == s_classinfo());
return m_outOfLineCapacity;
}
unsigned outOfLineSize() const
{
ASSERT(structure()->classInfo() == s_classinfo());
if (m_propertyTable) {
unsigned totalSize = m_propertyTable->propertyStorageSize();
unsigned inlineCapacity = this->inlineCapacity();
if (totalSize < inlineCapacity)
return 0;
return totalSize - inlineCapacity;
}
return numberOfOutOfLineSlotsForLastOffset(m_offset);
}
bool hasInlineStorage() const
{
return !!m_inlineCapacity;
}
unsigned inlineCapacity() const
{
return m_inlineCapacity;
}
unsigned inlineSize() const
{
unsigned result;
if (m_propertyTable)
result = m_propertyTable->propertyStorageSize();
else
result = m_offset + 1;
return std::min<unsigned>(result, m_inlineCapacity);
}
unsigned totalStorageSize() const
{
if (m_propertyTable)
return m_propertyTable->propertyStorageSize();
return numberOfSlotsForLastOffset(m_offset, m_typeInfo.type());
}
unsigned totalStorageCapacity() const
{
ASSERT(structure()->classInfo() == s_classinfo());
return m_outOfLineCapacity + inlineCapacity();
}
PropertyOffset firstValidOffset() const
{
if (hasInlineStorage())
return 0;
return firstOutOfLineOffset;
}
PropertyOffset lastValidOffset() const
{
if (m_propertyTable)
return propertyOffsetFor(m_propertyTable->propertyStorageSize() - 1, m_inlineCapacity);
return m_offset;
}
bool isValidOffset(PropertyOffset offset) const
{
return offset >= firstValidOffset()
&& offset <= lastValidOffset();
}
bool masqueradesAsUndefined(JSGlobalObject* lexicalGlobalObject);
PropertyOffset get(JSGlobalData&, PropertyName);
PropertyOffset get(JSGlobalData&, const WTF::String& name);
JS_EXPORT_PRIVATE PropertyOffset get(JSGlobalData&, PropertyName, unsigned& attributes, JSCell*& specificValue);
bool hasGetterSetterProperties() const { return m_hasGetterSetterProperties; }
bool hasReadOnlyOrGetterSetterPropertiesExcludingProto() const { return m_hasReadOnlyOrGetterSetterPropertiesExcludingProto; }
void setHasGetterSetterProperties(bool is__proto__)
{
m_hasGetterSetterProperties = true;
if (!is__proto__)
m_hasReadOnlyOrGetterSetterPropertiesExcludingProto = true;
}
void setContainsReadOnlyProperties()
{
m_hasReadOnlyOrGetterSetterPropertiesExcludingProto = true;
}
bool hasNonEnumerableProperties() const { return m_hasNonEnumerableProperties; }
bool isEmpty() const
{
if (m_propertyTable)
return m_propertyTable->isEmpty();
return !JSC::isValidOffset(m_offset);
}
JS_EXPORT_PRIVATE void despecifyDictionaryFunction(JSGlobalData&, PropertyName);
void disableSpecificFunctionTracking() { m_specificFunctionThrashCount = maxSpecificFunctionThrashCount; }
void setEnumerationCache(JSGlobalData&, JSPropertyNameIterator* enumerationCache); // Defined in JSPropertyNameIterator.h.
JSPropertyNameIterator* enumerationCache(); // Defined in JSPropertyNameIterator.h.
void getPropertyNamesFromStructure(JSGlobalData&, PropertyNameArray&, EnumerationMode);
JSString* objectToStringValue() { return m_objectToStringValue.get(); }
void setObjectToStringValue(JSGlobalData& globalData, const JSCell* owner, JSString* value)
{
m_objectToStringValue.set(globalData, owner, value);
}
bool staticFunctionsReified()
{
return m_staticFunctionReified;
}
void setStaticFunctionsReified()
{
m_staticFunctionReified = true;
}
const ClassInfo* classInfo() const { return m_classInfo; }
static ptrdiff_t prototypeOffset()
{
return OBJECT_OFFSETOF(Structure, m_prototype);
}
static ptrdiff_t globalObjectOffset()
{
return OBJECT_OFFSETOF(Structure, m_globalObject);
}
static ptrdiff_t typeInfoFlagsOffset()
{
return OBJECT_OFFSETOF(Structure, m_typeInfo) + TypeInfo::flagsOffset();
}
static ptrdiff_t typeInfoTypeOffset()
{
return OBJECT_OFFSETOF(Structure, m_typeInfo) + TypeInfo::typeOffset();
}
static ptrdiff_t classInfoOffset()
{
return OBJECT_OFFSETOF(Structure, m_classInfo);
}
static ptrdiff_t indexingTypeOffset()
{
return OBJECT_OFFSETOF(Structure, m_indexingType);
}
static Structure* createStructure(JSGlobalData&);
bool transitionWatchpointSetHasBeenInvalidated() const
{
return m_transitionWatchpointSet.hasBeenInvalidated();
}
bool transitionWatchpointSetIsStillValid() const
{
return m_transitionWatchpointSet.isStillValid();
}
void addTransitionWatchpoint(Watchpoint* watchpoint) const
{
ASSERT(transitionWatchpointSetIsStillValid());
m_transitionWatchpointSet.add(watchpoint);
}
void notifyTransitionFromThisStructure() const
{
m_transitionWatchpointSet.notifyWrite();
}
DECLARE_EXPORTED_CLASSINFO();
private:
friend class LLIntOffsetsExtractor;
JS_EXPORT_PRIVATE Structure(JSGlobalData&, JSGlobalObject*, JSValue prototype, const TypeInfo&, const ClassInfo*, IndexingType, PropertyOffset inlineCapacity);
Structure(JSGlobalData&);
Structure(JSGlobalData&, const Structure*);
static Structure* create(JSGlobalData&, const Structure*);
typedef enum {
NoneDictionaryKind = 0,
CachedDictionaryKind = 1,
UncachedDictionaryKind = 2
} DictionaryKind;
static Structure* toDictionaryTransition(JSGlobalData&, Structure*, DictionaryKind);
PropertyOffset putSpecificValue(JSGlobalData&, PropertyName, unsigned attributes, JSCell* specificValue);
PropertyOffset remove(PropertyName);
void createPropertyMap(unsigned keyCount = 0);
void checkConsistency();
bool despecifyFunction(JSGlobalData&, PropertyName);
void despecifyAllFunctions(JSGlobalData&);
PassOwnPtr<PropertyTable> copyPropertyTable(JSGlobalData&, Structure* owner);
PassOwnPtr<PropertyTable> copyPropertyTableForPinning(JSGlobalData&, Structure* owner);
JS_EXPORT_PRIVATE void materializePropertyMap(JSGlobalData&);
void materializePropertyMapIfNecessary(JSGlobalData& globalData)
{
ASSERT(structure()->classInfo() == s_classinfo());
if (!m_propertyTable && m_previous)
materializePropertyMap(globalData);
}
void materializePropertyMapIfNecessaryForPinning(JSGlobalData& globalData)
{
ASSERT(structure()->classInfo() == s_classinfo());
if (!m_propertyTable)
materializePropertyMap(globalData);
}
int transitionCount() const
{
// Since the number of transitions is always the same as m_offset, we keep the size of Structure down by not storing both.
return numberOfSlotsForLastOffset(m_offset, m_typeInfo.type());
}
bool isValid(JSGlobalObject*, StructureChain* cachedPrototypeChain) const;
bool isValid(ExecState*, StructureChain* cachedPrototypeChain) const;
void pin();
static const int s_maxTransitionLength = 64;
static const unsigned maxSpecificFunctionThrashCount = 3;
TypeInfo m_typeInfo;
IndexingType m_indexingType;
WriteBarrier<JSGlobalObject> m_globalObject;
WriteBarrier<Unknown> m_prototype;
mutable WriteBarrier<StructureChain> m_cachedPrototypeChain;
WriteBarrier<Structure> m_previous;
RefPtr<StringImpl> m_nameInPrevious;
WriteBarrier<JSCell> m_specificValueInPrevious;
const ClassInfo* m_classInfo;
StructureTransitionTable m_transitionTable;
WriteBarrier<JSPropertyNameIterator> m_enumerationCache;
OwnPtr<PropertyTable> m_propertyTable;
WriteBarrier<JSString> m_objectToStringValue;
mutable InlineWatchpointSet m_transitionWatchpointSet;
uint32_t m_outOfLineCapacity;
uint8_t m_inlineCapacity;
COMPILE_ASSERT(firstOutOfLineOffset < 256, firstOutOfLineOffset_fits);
// m_offset does not account for anonymous slots
PropertyOffset m_offset;
unsigned m_dictionaryKind : 2;
bool m_isPinnedPropertyTable : 1;
bool m_hasGetterSetterProperties : 1;
bool m_hasReadOnlyOrGetterSetterPropertiesExcludingProto : 1;
bool m_hasNonEnumerableProperties : 1;
unsigned m_attributesInPrevious : 22;
unsigned m_specificFunctionThrashCount : 2;
unsigned m_preventExtensions : 1;
unsigned m_didTransition : 1;
unsigned m_staticFunctionReified;
};
inline Structure* Structure::create(JSGlobalData& globalData, JSGlobalObject* globalObject, JSValue prototype, const TypeInfo& typeInfo, const ClassInfo* classInfo, IndexingType indexingType, PropertyOffset inlineCapacity)
{
ASSERT(globalData.structureStructure);
ASSERT(classInfo);
Structure* structure = new (NotNull, allocateCell<Structure>(globalData.heap)) Structure(globalData, globalObject, prototype, typeInfo, classInfo, indexingType, inlineCapacity);
structure->finishCreation(globalData);
return structure;
}
inline Structure* Structure::createStructure(JSGlobalData& globalData)
{
ASSERT(!globalData.structureStructure);
Structure* structure = new (NotNull, allocateCell<Structure>(globalData.heap)) Structure(globalData);
structure->finishCreation(globalData, CreatingEarlyCell);
return structure;
}
inline Structure* Structure::create(JSGlobalData& globalData, const Structure* structure)
{
ASSERT(globalData.structureStructure);
Structure* newStructure = new (NotNull, allocateCell<Structure>(globalData.heap)) Structure(globalData, structure);
newStructure->finishCreation(globalData);
return newStructure;
}
inline PropertyOffset Structure::get(JSGlobalData& globalData, PropertyName propertyName)
{
ASSERT(structure()->classInfo() == s_classinfo());
materializePropertyMapIfNecessary(globalData);
if (!m_propertyTable)
return invalidOffset;
PropertyMapEntry* entry = m_propertyTable->find(propertyName.uid()).first;
return entry ? entry->offset : invalidOffset;
}
inline PropertyOffset Structure::get(JSGlobalData& globalData, const WTF::String& name)
{
ASSERT(structure()->classInfo() == s_classinfo());
materializePropertyMapIfNecessary(globalData);
if (!m_propertyTable)
return invalidOffset;
PropertyMapEntry* entry = m_propertyTable->findWithString(name.impl()).first;
return entry ? entry->offset : invalidOffset;
}
inline bool Structure::masqueradesAsUndefined(JSGlobalObject* lexicalGlobalObject)
{
return typeInfo().masqueradesAsUndefined() && globalObject() == lexicalGlobalObject;
}
inline JSValue JSValue::structureOrUndefined() const
{
if (isCell())
return JSValue(asCell()->structure());
return jsUndefined();
}
inline bool JSCell::isObject() const
{
return m_structure->isObject();
}
inline bool JSCell::isString() const
{
return m_structure->typeInfo().type() == StringType;
}
inline bool JSCell::isGetterSetter() const
{
return m_structure->typeInfo().type() == GetterSetterType;
}
inline bool JSCell::isProxy() const
{
return structure()->typeInfo().type() == ProxyType;
}
inline bool JSCell::isAPIValueWrapper() const
{
return m_structure->typeInfo().type() == APIValueWrapperType;
}
inline void JSCell::setStructure(JSGlobalData& globalData, Structure* structure)
{
ASSERT(structure->typeInfo().overridesVisitChildren() == this->structure()->typeInfo().overridesVisitChildren());
ASSERT(structure->classInfo() == m_structure->classInfo());
ASSERT(!m_structure
|| m_structure->transitionWatchpointSetHasBeenInvalidated()
|| m_structure.get() == structure);
m_structure.set(globalData, this, structure);
}
ALWAYS_INLINE void SlotVisitor::internalAppend(JSCell* cell)
{
ASSERT(!m_isCheckingForDefaultMarkViolation);
if (!cell)
return;
#if ENABLE(GC_VALIDATION)
validate(cell);
#endif
if (Heap::testAndSetMarked(cell) || !cell->structure())
return;
m_visitCount++;
MARK_LOG_CHILD(*this, cell);
// Should never attempt to mark something that is zapped.
ASSERT(!cell->isZapped());
m_stack.append(cell);
}
inline StructureTransitionTable::Hash::Key StructureTransitionTable::keyForWeakGCMapFinalizer(void*, Structure* structure)
{
// Newer versions of the STL have an std::make_pair function that takes rvalue references.
// When either of the parameters are bitfields, the C++ compiler will try to bind them as lvalues, which is invalid. To work around this, use unary "+" to make the parameter an rvalue.
// See https://bugs.webkit.org/show_bug.cgi?id=59261 for more details.
return Hash::Key(structure->m_nameInPrevious.get(), +structure->m_attributesInPrevious);
}
inline bool Structure::transitivelyTransitionedFrom(Structure* structureToFind)
{
for (Structure* current = this; current; current = current->previousID()) {
if (current == structureToFind)
return true;
}
return false;
}
inline JSCell::JSCell(JSGlobalData& globalData, Structure* structure)
: m_structure(globalData, this, structure)
{
}
inline void JSCell::finishCreation(JSGlobalData& globalData, Structure* structure, CreatingEarlyCellTag)
{
#if ENABLE(GC_VALIDATION)
ASSERT(globalData.isInitializingObject());
globalData.setInitializingObjectClass(0);
if (structure)
#endif
m_structure.setEarlyValue(globalData, this, structure);
// Very first set of allocations won't have a real structure.
ASSERT(m_structure || !globalData.structureStructure);
}
} // namespace JSC
#endif // Structure_h