// In future we may want to cache this transition.
Structure* Structure::preventExtensionsTransition(JSGlobalData& globalData, Structure* structure)
{
Structure* transition = create(globalData, structure);
// Don't set m_offset, as one can not transition to this.
structure->materializePropertyMapIfNecessary(globalData);
transition->m_propertyTable = structure->copyPropertyTableForPinning(globalData, transition);
transition->m_preventExtensions = true;
transition->pin();
return transition;
}
Structure* Structure::toDictionaryTransition(JSGlobalData& globalData, Structure* structure, DictionaryKind kind)
{
ASSERT(!structure->isUncacheableDictionary());
Structure* transition = create(globalData, structure);
structure->materializePropertyMapIfNecessary(globalData);
transition->m_propertyTable = structure->copyPropertyTableForPinning(globalData, transition);
transition->m_dictionaryKind = kind;
transition->pin();
return transition;
}
Structure* Structure::changePrototypeTransition(JSGlobalData& globalData, Structure* structure, JSValue prototype)
{
Structure* transition = create(globalData, structure);
transition->m_prototype.set(globalData, transition, prototype);
// Don't set m_offset, as one can not transition to this.
structure->materializePropertyMapIfNecessary(globalData);
transition->m_propertyTable = structure->copyPropertyTableForPinning(globalData, transition);
transition->pin();
return transition;
}
Structure* Structure::changePrototypeTransition(JSGlobalData& globalData, Structure* structure, JSValue prototype)
{
Structure* transition = create(globalData, structure);
transition->m_prototype.set(globalData, transition, prototype);
structure->materializePropertyMapIfNecessary(globalData);
transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
transition->m_offset = structure->m_offset;
transition->pin();
transition->checkOffsetConsistency();
return transition;
}
Structure* Structure::changePrototypeTransition(VM& vm, Structure* structure, JSValue prototype)
{
Structure* transition = create(vm, structure);
transition->m_prototype.set(vm, transition, prototype);
DeferGC deferGC(vm.heap);
structure->materializePropertyMapIfNecessary(vm, deferGC);
transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
transition->m_offset = structure->m_offset;
transition->pin();
transition->checkOffsetConsistency();
return transition;
}
// In future we may want to cache this transition.
Structure* Structure::preventExtensionsTransition(VM& vm, Structure* structure)
{
Structure* transition = create(vm, structure);
// Don't set m_offset, as one can not transition to this.
DeferGC deferGC(vm.heap);
structure->materializePropertyMapIfNecessary(vm, deferGC);
transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
transition->m_offset = structure->m_offset;
transition->setPreventExtensions(true);
transition->pin();
transition->checkOffsetConsistency();
return transition;
}
Structure* Structure::toDictionaryTransition(VM& vm, Structure* structure, DictionaryKind kind)
{
ASSERT(!structure->isUncacheableDictionary());
Structure* transition = create(vm, structure);
DeferGC deferGC(vm.heap);
structure->materializePropertyMapIfNecessary(vm, deferGC);
transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
transition->m_offset = structure->m_offset;
transition->setDictionaryKind(kind);
transition->pin();
transition->checkOffsetConsistency();
return transition;
}
Structure* Structure::attributeChangeTransition(JSGlobalData& globalData, Structure* structure, PropertyName propertyName, unsigned attributes)
{
if (!structure->isUncacheableDictionary()) {
Structure* transition = create(globalData, structure);
// Don't set m_offset, as one can not transition to this.
structure->materializePropertyMapIfNecessary(globalData);
transition->m_propertyTable = structure->copyPropertyTableForPinning(globalData, transition);
transition->pin();
structure = transition;
}
ASSERT(structure->m_propertyTable);
PropertyMapEntry* entry = structure->m_propertyTable->find(propertyName.uid()).first;
ASSERT(entry);
entry->attributes = attributes;
return structure;
}
Structure* Structure::attributeChangeTransition(JSGlobalData& globalData, Structure* structure, PropertyName propertyName, unsigned attributes)
{
if (!structure->isUncacheableDictionary()) {
Structure* transition = create(globalData, structure);
structure->materializePropertyMapIfNecessary(globalData);
transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
transition->m_offset = structure->m_offset;
transition->pin();
structure = transition;
}
ASSERT(structure->propertyTable());
PropertyMapEntry* entry = structure->propertyTable()->find(propertyName.uid()).first;
ASSERT(entry);
entry->attributes = attributes;
structure->checkOffsetConsistency();
return structure;
}
Structure* Structure::despecifyFunctionTransition(JSGlobalData& globalData, Structure* structure, PropertyName replaceFunction)
{
ASSERT(structure->m_specificFunctionThrashCount < maxSpecificFunctionThrashCount);
Structure* transition = create(globalData, structure);
++transition->m_specificFunctionThrashCount;
// Don't set m_offset, as one can not transition to this.
structure->materializePropertyMapIfNecessary(globalData);
transition->m_propertyTable = structure->copyPropertyTableForPinning(globalData, transition);
transition->pin();
if (transition->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
transition->despecifyAllFunctions(globalData);
else {
bool removed = transition->despecifyFunction(globalData, replaceFunction);
ASSERT_UNUSED(removed, removed);
}
return transition;
}
Structure* Structure::attributeChangeTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes)
{
DeferGC deferGC(vm.heap);
if (!structure->isUncacheableDictionary()) {
Structure* transition = create(vm, structure);
structure->materializePropertyMapIfNecessary(vm, deferGC);
transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
transition->m_offset = structure->m_offset;
transition->pin();
structure = transition;
}
ASSERT(structure->propertyTable());
PropertyMapEntry* entry = structure->propertyTable()->get(propertyName.uid());
ASSERT(entry);
entry->attributes = attributes;
structure->checkOffsetConsistency();
return structure;
}
Structure* Structure::despecifyFunctionTransition(JSGlobalData& globalData, Structure* structure, PropertyName replaceFunction)
{
ASSERT(structure->m_specificFunctionThrashCount < maxSpecificFunctionThrashCount);
Structure* transition = create(globalData, structure);
++transition->m_specificFunctionThrashCount;
structure->materializePropertyMapIfNecessary(globalData);
transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
transition->m_offset = structure->m_offset;
transition->pin();
if (transition->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
transition->despecifyAllFunctions(globalData);
else {
bool removed = transition->despecifyFunction(globalData, replaceFunction);
ASSERT_UNUSED(removed, removed);
}
transition->checkOffsetConsistency();
return transition;
}
Structure* Structure::nonPropertyTransition(VM& vm, Structure* structure, NonPropertyTransition transitionKind)
{
unsigned attributes = toAttributes(transitionKind);
IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);
if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
if (globalObject->isOriginalArrayStructure(structure)) {
Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
if (result->indexingTypeIncludingHistory() == indexingType) {
structure->didTransitionFromThisStructure();
return result;
}
}
}
Structure* existingTransition;
if (!structure->isDictionary() && (existingTransition = structure->m_transitionTable.get(0, attributes))) {
ASSERT(existingTransition->attributesInPrevious() == attributes);
ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
return existingTransition;
}
Structure* transition = create(vm, structure);
transition->setAttributesInPrevious(attributes);
transition->m_blob.setIndexingType(indexingType);
transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
transition->m_offset = structure->m_offset;
checkOffset(transition->m_offset, transition->inlineCapacity());
if (structure->isDictionary())
transition->pin();
else {
ConcurrentJITLocker locker(structure->m_lock);
structure->m_transitionTable.add(vm, transition);
}
transition->checkOffsetConsistency();
return transition;
}
Structure* Structure::nonPropertyTransition(VM& vm, Structure* structure, NonPropertyTransition transitionKind)
{
unsigned attributes = toAttributes(transitionKind);
IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);
if (changesIndexingType(transitionKind)) {
if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
if (globalObject->isOriginalArrayStructure(structure)) {
Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
if (result->indexingTypeIncludingHistory() == indexingType) {
structure->didTransitionFromThisStructure();
return result;
}
}
}
}
Structure* existingTransition;
if (!structure->isDictionary() && (existingTransition = structure->m_transitionTable.get(0, attributes))) {
ASSERT(existingTransition->attributesInPrevious() == attributes);
ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
return existingTransition;
}
DeferGC deferGC(vm.heap);
Structure* transition = create(vm, structure);
transition->setAttributesInPrevious(attributes);
transition->m_blob.setIndexingType(indexingType);
if (preventsExtensions(transitionKind))
transition->setDidPreventExtensions(true);
if (setsDontDeleteOnAllProperties(transitionKind)
|| setsReadOnlyOnNonAccessorProperties(transitionKind)) {
// We pin the property table on transitions that do wholesale editing of the property
// table, since our logic for walking the property transition chain to rematerialize the
// table doesn't know how to take into account such wholesale edits.
structure->materializePropertyMapIfNecessary(vm, deferGC);
transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
transition->m_offset = structure->m_offset;
transition->pinForCaching();
if (transition->propertyTable()) {
for (auto& entry : *transition->propertyTable().get()) {
if (setsDontDeleteOnAllProperties(transitionKind))
entry.attributes |= DontDelete;
if (setsReadOnlyOnNonAccessorProperties(transitionKind) && !(entry.attributes & Accessor))
entry.attributes |= ReadOnly;
}
}
} else {
transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
transition->m_offset = structure->m_offset;
checkOffset(transition->m_offset, transition->inlineCapacity());
}
if (setsReadOnlyOnNonAccessorProperties(transitionKind)
&& transition->propertyTable()
&& !transition->propertyTable()->isEmpty())
transition->setHasReadOnlyOrGetterSetterPropertiesExcludingProto(true);
if (structure->isDictionary())
transition->pin();
else {
ConcurrentJITLocker locker(structure->m_lock);
structure->m_transitionTable.add(vm, transition);
}
transition->checkOffsetConsistency();
return transition;
}