| /* |
| * Copyright (C) 2008-2021 Apple Inc. All rights reserved. |
| * Copyright (C) 2020 Alexey Shvayka <shvaikalesh@gmail.com>. |
| * |
| * 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 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 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. |
| */ |
| |
| #include "config.h" |
| #include "Structure.h" |
| |
| #include "BrandedStructure.h" |
| #include "BuiltinNames.h" |
| #include "DumpContext.h" |
| #include "JSCInlines.h" |
| #include "PropertyNameArray.h" |
| #include "PropertyTable.h" |
| #include <wtf/CommaPrinter.h> |
| #include <wtf/NeverDestroyed.h> |
| #include <wtf/RefPtr.h> |
| |
| #define DUMP_STRUCTURE_ID_STATISTICS 0 |
| |
| namespace JSC { |
| |
| #if DUMP_STRUCTURE_ID_STATISTICS |
| static HashSet<Structure*>& liveStructureSet = *(new HashSet<Structure*>); |
| #endif |
| |
| class SingleSlotTransitionWeakOwner final : public WeakHandleOwner { |
| void finalize(Handle<Unknown>, void* context) final |
| { |
| StructureTransitionTable* table = reinterpret_cast<StructureTransitionTable*>(context); |
| ASSERT(table->isUsingSingleSlot()); |
| WeakSet::deallocate(table->weakImpl()); |
| table->m_data = StructureTransitionTable::UsingSingleSlotFlag; |
| } |
| }; |
| |
| static SingleSlotTransitionWeakOwner& singleSlotTransitionWeakOwner() |
| { |
| static NeverDestroyed<SingleSlotTransitionWeakOwner> owner; |
| return owner; |
| } |
| |
| inline void StructureTransitionTable::setSingleTransition(Structure* structure) |
| { |
| ASSERT(isUsingSingleSlot()); |
| if (WeakImpl* impl = this->weakImpl()) |
| WeakSet::deallocate(impl); |
| WeakImpl* impl = WeakSet::allocate(structure, &singleSlotTransitionWeakOwner(), this); |
| m_data = bitwise_cast<intptr_t>(impl) | UsingSingleSlotFlag; |
| } |
| |
| bool StructureTransitionTable::contains(UniquedStringImpl* rep, unsigned attributes, TransitionKind transitionKind) const |
| { |
| if (isUsingSingleSlot()) { |
| Structure* transition = singleTransition(); |
| return transition && transition->m_transitionPropertyName == rep && transition->transitionPropertyAttributes() == attributes && transition->transitionKind() == transitionKind; |
| } |
| return map()->get(StructureTransitionTable::Hash::Key(rep, attributes, transitionKind)); |
| } |
| |
| void StructureTransitionTable::add(VM& vm, Structure* structure) |
| { |
| if (isUsingSingleSlot()) { |
| Structure* existingTransition = singleTransition(); |
| |
| // This handles the first transition being added. |
| if (!existingTransition) { |
| setSingleTransition(structure); |
| return; |
| } |
| |
| // This handles the second transition being added |
| // (or the first transition being despecified!) |
| setMap(new TransitionMap(vm)); |
| add(vm, existingTransition); |
| } |
| |
| // Add the structure to the map. |
| map()->set(StructureTransitionTable::Hash::Key(structure->m_transitionPropertyName.get(), structure->transitionPropertyAttributes(), structure->transitionKind()), structure); |
| } |
| |
| void Structure::dumpStatistics() |
| { |
| #if DUMP_STRUCTURE_ID_STATISTICS |
| unsigned numberLeaf = 0; |
| unsigned numberUsingSingleSlot = 0; |
| unsigned numberSingletons = 0; |
| unsigned numberWithPropertyMaps = 0; |
| unsigned totalPropertyMapsSize = 0; |
| |
| HashSet<Structure*>::const_iterator end = liveStructureSet.end(); |
| for (HashSet<Structure*>::const_iterator it = liveStructureSet.begin(); it != end; ++it) { |
| Structure* structure = *it; |
| |
| switch (structure->m_transitionTable.size()) { |
| case 0: |
| ++numberLeaf; |
| if (!structure->previousID()) |
| ++numberSingletons; |
| break; |
| |
| case 1: |
| ++numberUsingSingleSlot; |
| break; |
| } |
| |
| if (PropertyTable* table = structure->propertyTableOrNull()) { |
| ++numberWithPropertyMaps; |
| totalPropertyMapsSize += table->sizeInMemory(); |
| } |
| } |
| |
| dataLogF("Number of live Structures: %d\n", liveStructureSet.size()); |
| dataLogF("Number of Structures using the single item optimization for transition map: %d\n", numberUsingSingleSlot); |
| dataLogF("Number of Structures that are leaf nodes: %d\n", numberLeaf); |
| dataLogF("Number of Structures that singletons: %d\n", numberSingletons); |
| dataLogF("Number of Structures with PropertyMaps: %d\n", numberWithPropertyMaps); |
| |
| dataLogF("Size of a single Structures: %d\n", static_cast<unsigned>(sizeof(Structure))); |
| dataLogF("Size of sum of all property maps: %d\n", totalPropertyMapsSize); |
| dataLogF("Size of average of all property maps: %f\n", static_cast<double>(totalPropertyMapsSize) / static_cast<double>(liveStructureSet.size())); |
| #else |
| dataLogF("Dumping Structure statistics is not enabled.\n"); |
| #endif |
| } |
| |
| #if ASSERT_ENABLED |
| void Structure::validateFlags() |
| { |
| const MethodTable& methodTable = m_classInfo->methodTable; |
| |
| bool overridesGetCallData = methodTable.getCallData != JSCell::getCallData; |
| RELEASE_ASSERT(overridesGetCallData == typeInfo().overridesGetCallData()); |
| |
| bool overridesGetOwnPropertySlot = |
| methodTable.getOwnPropertySlot != JSObject::getOwnPropertySlot |
| && methodTable.getOwnPropertySlot != JSCell::getOwnPropertySlot; |
| // We can strengthen this into an equivalence test if there are no classes |
| // that specifies this flag without overriding getOwnPropertySlot. |
| // FIXME: https://bugs.webkit.org/show_bug.cgi?id=212956 |
| if (overridesGetOwnPropertySlot) |
| RELEASE_ASSERT(typeInfo().overridesGetOwnPropertySlot()); |
| |
| bool overridesGetOwnPropertySlotByIndex = |
| methodTable.getOwnPropertySlotByIndex != JSObject::getOwnPropertySlotByIndex |
| && methodTable.getOwnPropertySlotByIndex != JSCell::getOwnPropertySlotByIndex; |
| // We can strengthen this into an equivalence test if there are no classes |
| // that specifies this flag without overriding getOwnPropertySlotByIndex. |
| // FIXME: https://bugs.webkit.org/show_bug.cgi?id=212958 |
| if (overridesGetOwnPropertySlotByIndex) |
| RELEASE_ASSERT(typeInfo().interceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero()); |
| |
| bool overridesGetOwnPropertyNames = |
| methodTable.getOwnPropertyNames != JSObject::getOwnPropertyNames |
| && methodTable.getOwnPropertyNames != JSCell::getOwnPropertyNames; |
| RELEASE_ASSERT(overridesGetOwnPropertyNames == typeInfo().overridesGetOwnPropertyNames()); |
| |
| bool overridesGetOwnSpecialPropertyNames = |
| methodTable.getOwnSpecialPropertyNames != JSObject::getOwnSpecialPropertyNames |
| && methodTable.getOwnSpecialPropertyNames != JSCell::getOwnSpecialPropertyNames; |
| RELEASE_ASSERT(overridesGetOwnSpecialPropertyNames == typeInfo().overridesGetOwnSpecialPropertyNames()); |
| |
| bool overridesGetPrototype = |
| methodTable.getPrototype != static_cast<MethodTable::GetPrototypeFunctionPtr>(JSObject::getPrototype) |
| && methodTable.getPrototype != JSCell::getPrototype; |
| RELEASE_ASSERT(overridesGetPrototype == typeInfo().overridesGetPrototype()); |
| |
| bool overridesPut = |
| methodTable.put != JSObject::put |
| && methodTable.put != JSCell::put; |
| RELEASE_ASSERT(overridesPut == typeInfo().overridesPut()); |
| } |
| #else |
| inline void Structure::validateFlags() { } |
| #endif |
| |
| Structure::Structure(VM& vm, JSGlobalObject* globalObject, JSValue prototype, const TypeInfo& typeInfo, const ClassInfo* classInfo, IndexingType indexingType, unsigned inlineCapacity) |
| : JSCell(vm, vm.structureStructure.get()) |
| , m_blob(vm.heap.structureIDTable().allocateID(this), indexingType, typeInfo) |
| , m_outOfLineTypeFlags(typeInfo.outOfLineTypeFlags()) |
| , m_inlineCapacity(inlineCapacity) |
| , m_bitField(0) |
| , m_globalObject(vm, this, globalObject, WriteBarrier<JSGlobalObject>::MayBeNull) |
| , m_prototype(vm, this, prototype) |
| , m_classInfo(classInfo) |
| , m_transitionWatchpointSet(IsWatched) |
| , m_propertyHash(0) |
| { |
| setDictionaryKind(NoneDictionaryKind); |
| setIsPinnedPropertyTable(false); |
| setHasGetterSetterProperties(classInfo->hasStaticSetterOrReadonlyProperties()); |
| setHasCustomGetterSetterProperties(false); |
| setHasReadOnlyOrGetterSetterPropertiesExcludingProto(classInfo->hasStaticSetterOrReadonlyProperties()); |
| setHasUnderscoreProtoPropertyExcludingOriginalProto(false); |
| setIsQuickPropertyAccessAllowedForEnumeration(true); |
| setTransitionPropertyAttributes(0); |
| setTransitionKind(TransitionKind::Unknown); |
| setDidPreventExtensions(false); |
| setDidTransition(false); |
| setStaticPropertiesReified(false); |
| setTransitionWatchpointIsLikelyToBeFired(false); |
| setHasBeenDictionary(false); |
| setProtectPropertyTableWhileTransitioning(false); |
| setTransitionOffset(vm, invalidOffset); |
| setMaxOffset(vm, invalidOffset); |
| |
| ASSERT(inlineCapacity <= JSFinalObject::maxInlineCapacity()); |
| ASSERT(static_cast<PropertyOffset>(inlineCapacity) < firstOutOfLineOffset); |
| ASSERT(!hasRareData()); |
| ASSERT(hasReadOnlyOrGetterSetterPropertiesExcludingProto() == m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| ASSERT(hasGetterSetterProperties() == m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| |
| validateFlags(); |
| } |
| |
| const ClassInfo Structure::s_info = { "Structure", nullptr, nullptr, nullptr, CREATE_METHOD_TABLE(Structure) }; |
| |
| Structure::Structure(VM& vm, CreatingEarlyCellTag) |
| : JSCell(CreatingEarlyCell) |
| , m_inlineCapacity(0) |
| , m_bitField(0) |
| , m_prototype(vm, this, jsNull()) |
| , m_classInfo(info()) |
| , m_transitionWatchpointSet(IsWatched) |
| , m_propertyHash(0) |
| { |
| setDictionaryKind(NoneDictionaryKind); |
| setIsPinnedPropertyTable(false); |
| setHasGetterSetterProperties(m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| setHasCustomGetterSetterProperties(false); |
| setHasReadOnlyOrGetterSetterPropertiesExcludingProto(m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| setHasUnderscoreProtoPropertyExcludingOriginalProto(false); |
| setIsQuickPropertyAccessAllowedForEnumeration(true); |
| setTransitionPropertyAttributes(0); |
| setTransitionKind(TransitionKind::Unknown); |
| setDidPreventExtensions(false); |
| setDidTransition(false); |
| setStaticPropertiesReified(false); |
| setTransitionWatchpointIsLikelyToBeFired(false); |
| setHasBeenDictionary(false); |
| setProtectPropertyTableWhileTransitioning(false); |
| setTransitionOffset(vm, invalidOffset); |
| setMaxOffset(vm, invalidOffset); |
| |
| TypeInfo typeInfo = TypeInfo(StructureType, StructureFlags); |
| m_blob = StructureIDBlob(vm.heap.structureIDTable().allocateID(this), 0, typeInfo); |
| m_outOfLineTypeFlags = typeInfo.outOfLineTypeFlags(); |
| |
| ASSERT(hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| ASSERT(hasGetterSetterProperties() || !m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| ASSERT(!this->typeInfo().overridesGetCallData() || m_classInfo->methodTable.getCallData != &JSCell::getCallData); |
| } |
| |
| Structure::Structure(VM& vm, Structure* previous, DeferredStructureTransitionWatchpointFire* deferred) |
| : JSCell(vm, vm.structureStructure.get()) |
| , m_inlineCapacity(previous->m_inlineCapacity) |
| , m_bitField(0) |
| , m_prototype(vm, this, previous->m_prototype.get()) |
| , m_classInfo(previous->m_classInfo) |
| , m_transitionWatchpointSet(IsWatched) |
| , m_propertyHash(previous->m_propertyHash) |
| , m_seenProperties(previous->m_seenProperties) |
| { |
| setDictionaryKind(previous->dictionaryKind()); |
| setIsPinnedPropertyTable(false); |
| setHasBeenFlattenedBefore(previous->hasBeenFlattenedBefore()); |
| setHasGetterSetterProperties(previous->hasGetterSetterProperties()); |
| setHasCustomGetterSetterProperties(previous->hasCustomGetterSetterProperties()); |
| setHasReadOnlyOrGetterSetterPropertiesExcludingProto(previous->hasReadOnlyOrGetterSetterPropertiesExcludingProto()); |
| setHasUnderscoreProtoPropertyExcludingOriginalProto(previous->hasUnderscoreProtoPropertyExcludingOriginalProto()); |
| setIsQuickPropertyAccessAllowedForEnumeration(previous->isQuickPropertyAccessAllowedForEnumeration()); |
| setTransitionPropertyAttributes(0); |
| setTransitionKind(TransitionKind::Unknown); |
| setDidPreventExtensions(previous->didPreventExtensions()); |
| setDidTransition(true); |
| setStaticPropertiesReified(previous->staticPropertiesReified()); |
| setHasBeenDictionary(previous->hasBeenDictionary()); |
| setProtectPropertyTableWhileTransitioning(false); |
| setTransitionOffset(vm, invalidOffset); |
| setMaxOffset(vm, invalidOffset); |
| |
| TypeInfo typeInfo = previous->typeInfo(); |
| m_blob = StructureIDBlob(vm.heap.structureIDTable().allocateID(this), previous->indexingModeIncludingHistory(), typeInfo); |
| m_outOfLineTypeFlags = typeInfo.outOfLineTypeFlags(); |
| |
| ASSERT(!previous->typeInfo().structureIsImmortal()); |
| setPreviousID(vm, previous); |
| |
| previous->didTransitionFromThisStructure(deferred); |
| |
| // Copy this bit now, in case previous was being watched. |
| setTransitionWatchpointIsLikelyToBeFired(previous->transitionWatchpointIsLikelyToBeFired()); |
| |
| if (previous->m_globalObject) |
| m_globalObject.set(vm, this, previous->m_globalObject.get()); |
| ASSERT(hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| ASSERT(hasGetterSetterProperties() || !m_classInfo->hasStaticSetterOrReadonlyProperties()); |
| ASSERT(!this->typeInfo().overridesGetCallData() || m_classInfo->methodTable.getCallData != &JSCell::getCallData); |
| } |
| |
| Structure::~Structure() |
| { |
| if (typeInfo().structureIsImmortal()) |
| return; |
| |
| if (isBrandedStructure()) |
| static_cast<BrandedStructure*>(this)->destruct(); |
| Heap::heap(this)->structureIDTable().deallocateID(this, m_blob.structureID()); |
| } |
| |
| void Structure::destroy(JSCell* cell) |
| { |
| static_cast<Structure*>(cell)->Structure::~Structure(); |
| } |
| |
| Structure* Structure::create(PolyProtoTag, VM& vm, JSGlobalObject* globalObject, JSObject* prototype, const TypeInfo& typeInfo, const ClassInfo* classInfo, IndexingType indexingType, unsigned inlineCapacity) |
| { |
| Structure* result = create(vm, globalObject, prototype, typeInfo, classInfo, indexingType, inlineCapacity); |
| |
| unsigned oldOutOfLineCapacity = result->outOfLineCapacity(); |
| result->addPropertyWithoutTransition( |
| vm, vm.propertyNames->builtinNames().polyProtoName(), static_cast<unsigned>(PropertyAttribute::DontEnum), |
| [&] (const GCSafeConcurrentJSLocker&, PropertyOffset offset, PropertyOffset newMaxOffset) { |
| RELEASE_ASSERT(Structure::outOfLineCapacity(newMaxOffset) == oldOutOfLineCapacity); |
| RELEASE_ASSERT(offset == knownPolyProtoOffset); |
| RELEASE_ASSERT(isInlineOffset(knownPolyProtoOffset)); |
| result->m_prototype.setWithoutWriteBarrier(JSValue()); |
| result->setMaxOffset(vm, newMaxOffset); |
| }); |
| |
| ASSERT(result->type() == StructureType); |
| return result; |
| } |
| |
| bool Structure::isValidPrototype(JSValue prototype) |
| { |
| return prototype.isNull() || (prototype.isObject() && prototype.getObject()->mayBePrototype()); |
| } |
| |
| bool Structure::findStructuresAndMapForMaterialization(Vector<Structure*, 8>& structures, Structure*& structure, PropertyTable*& table) |
| { |
| ASSERT(structures.isEmpty()); |
| table = nullptr; |
| |
| for (structure = this; structure; structure = structure->previousID()) { |
| structure->m_lock.lock(); |
| |
| table = structure->propertyTableOrNull(); |
| if (table) { |
| // Leave the structure locked, so that the caller can do things to it atomically |
| // before it loses its property table. |
| return true; |
| } |
| |
| structures.append(structure); |
| structure->m_lock.unlock(); |
| } |
| |
| ASSERT(!structure); |
| ASSERT(!table); |
| return false; |
| } |
| |
| PropertyTable* Structure::materializePropertyTable(VM& vm, bool setPropertyTable) |
| { |
| ASSERT(structure(vm)->classInfo() == info()); |
| ASSERT(!protectPropertyTableWhileTransitioning()); |
| |
| DeferGC deferGC(vm); |
| |
| Vector<Structure*, 8> structures; |
| Structure* structure; |
| PropertyTable* table; |
| |
| bool didFindStructure = findStructuresAndMapForMaterialization(structures, structure, table); |
| |
| unsigned capacity = numberOfSlotsForMaxOffset(maxOffset(), m_inlineCapacity); |
| if (didFindStructure) { |
| table = table->copy(vm, capacity); |
| structure->m_lock.unlock(); |
| } else |
| table = PropertyTable::create(vm, capacity); |
| |
| // Must hold the lock on this structure, since we will be modifying this structure's |
| // property map. We don't want getConcurrently() to see the property map in a half-baked |
| // state. |
| GCSafeConcurrentJSLocker locker(m_lock, vm); |
| if (setPropertyTable) |
| this->setPropertyTable(vm, table); |
| |
| for (size_t i = structures.size(); i--;) { |
| structure = structures[i]; |
| if (!structure->m_transitionPropertyName || structure->transitionKind() == TransitionKind::SetBrand) |
| continue; |
| switch (structure->transitionKind()) { |
| case TransitionKind::PropertyAddition: { |
| PropertyMapEntry entry(structure->m_transitionPropertyName.get(), structure->transitionOffset(), structure->transitionPropertyAttributes()); |
| auto nextOffset = table->nextOffset(structure->inlineCapacity()); |
| ASSERT_UNUSED(nextOffset, nextOffset == structure->transitionOffset()); |
| auto result = table->add(vm, entry); |
| ASSERT_UNUSED(result, result.second); |
| ASSERT_UNUSED(result, result.first.first->offset == nextOffset); |
| break; |
| } |
| case TransitionKind::PropertyDeletion: { |
| auto item = table->find(structure->m_transitionPropertyName.get()); |
| ASSERT(item.first); |
| table->remove(vm, item); |
| table->addDeletedOffset(structure->transitionOffset()); |
| break; |
| } |
| case TransitionKind::PropertyAttributeChange: { |
| PropertyMapEntry* entry = table->get(structure->m_transitionPropertyName.get()); |
| entry->attributes = structure->transitionPropertyAttributes(); |
| ASSERT(entry->offset == structure->transitionOffset()); |
| break; |
| } |
| default: |
| ASSERT_NOT_REACHED(); |
| break; |
| } |
| } |
| |
| checkOffsetConsistency( |
| table, |
| [&] () { |
| dataLog("Detected in materializePropertyTable.\n"); |
| dataLog("Found structure = ", RawPointer(structure), "\n"); |
| dataLog("structures = "); |
| CommaPrinter comma; |
| for (Structure* structure : structures) |
| dataLog(comma, RawPointer(structure)); |
| dataLog("\n"); |
| }); |
| |
| return table; |
| } |
| |
| bool Structure::holesMustForwardToPrototype(VM& vm, JSObject* base) const |
| { |
| ASSERT(base->structure(vm) == this); |
| |
| if (this->mayInterceptIndexedAccesses()) |
| return true; |
| |
| JSValue prototype = this->storedPrototype(base); |
| if (!prototype.isObject()) |
| return false; |
| JSObject* object = asObject(prototype); |
| |
| while (true) { |
| Structure& structure = *object->structure(vm); |
| if (hasIndexedProperties(object->indexingType()) || structure.mayInterceptIndexedAccesses()) |
| return true; |
| prototype = structure.storedPrototype(object); |
| if (!prototype.isObject()) |
| return false; |
| object = asObject(prototype); |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| return false; |
| } |
| |
| Structure* Structure::addPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, PropertyOffset& offset) |
| { |
| Structure* newStructure = addPropertyTransitionToExistingStructure(structure, propertyName, attributes, offset); |
| if (newStructure) |
| return newStructure; |
| |
| return addNewPropertyTransition( |
| vm, structure, propertyName, attributes, offset, PutPropertySlot::UnknownContext); |
| } |
| |
| Structure* Structure::addNewPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, PropertyOffset& offset, PutPropertySlot::Context context, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| ASSERT(!structure->isDictionary()); |
| ASSERT(structure->isObject()); |
| ASSERT(!Structure::addPropertyTransitionToExistingStructure(structure, propertyName, attributes, offset)); |
| |
| int maxTransitionLength; |
| if (context == PutPropertySlot::PutById) |
| maxTransitionLength = s_maxTransitionLengthForNonEvalPutById; |
| else |
| maxTransitionLength = s_maxTransitionLength; |
| if (structure->transitionCountEstimate() > maxTransitionLength) { |
| ASSERT(!isCopyOnWrite(structure->indexingMode())); |
| Structure* transition = toCacheableDictionaryTransition(vm, structure, deferred); |
| ASSERT(structure != transition); |
| offset = transition->add(vm, propertyName, attributes); |
| return transition; |
| } |
| |
| Structure* transition = create(vm, structure, deferred); |
| |
| transition->m_cachedPrototypeChain.setMayBeNull(vm, transition, structure->m_cachedPrototypeChain.get()); |
| |
| // While we are adding the property, rematerializing the property table is super weird: we already |
| // have a m_transitionPropertyName and transitionPropertyAttributes but the m_transitionOffset is still wrong. If the |
| // materialization algorithm runs, it'll build a property table that already has the property but |
| // at a bogus offset. Rather than try to teach the materialization code how to create a table under |
| // those conditions, we just tell the GC not to blow the table away during this period of time. |
| // Holding the lock ensures that we either do this before the GC starts scanning the structure, in |
| // which case the GC will not blow the table away, or we do it after the GC already ran in which |
| // case all is well. If it wasn't for the lock, the GC would have TOCTOU: if could read |
| // protectPropertyTableWhileTransitioning before we set it to true, and then blow the table away after. |
| { |
| ConcurrentJSLocker locker(transition->m_lock); |
| transition->setProtectPropertyTableWhileTransitioning(true); |
| } |
| |
| transition->m_blob.setIndexingModeIncludingHistory(structure->indexingModeIncludingHistory() & ~CopyOnWrite); |
| transition->m_transitionPropertyName = propertyName.uid(); |
| transition->setTransitionPropertyAttributes(attributes); |
| transition->setTransitionKind(TransitionKind::PropertyAddition); |
| transition->setPropertyTable(vm, structure->takePropertyTableOrCloneIfPinned(vm)); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| |
| offset = transition->add(vm, propertyName, attributes); |
| transition->setTransitionOffset(vm, offset); |
| |
| // Now that everything is fine with the new structure's bookkeeping, the GC is free to blow the |
| // table away if it wants. We can now rebuild it fine. |
| WTF::storeStoreFence(); |
| transition->setProtectPropertyTableWhileTransitioning(false); |
| |
| checkOffset(transition->transitionOffset(), transition->inlineCapacity()); |
| if (!structure->hasBeenDictionary()) { |
| GCSafeConcurrentJSLocker locker(structure->m_lock, vm); |
| structure->m_transitionTable.add(vm, transition); |
| } |
| transition->checkOffsetConsistency(); |
| structure->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| Structure* Structure::removePropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, PropertyOffset& offset, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| Structure* newStructure = removePropertyTransitionFromExistingStructure(structure, propertyName, offset); |
| if (newStructure) |
| return newStructure; |
| |
| return removeNewPropertyTransition( |
| vm, structure, propertyName, offset, deferred); |
| } |
| |
| Structure* Structure::removePropertyTransitionFromExistingStructureImpl(Structure* structure, PropertyName propertyName, unsigned attributes, PropertyOffset& offset) |
| { |
| ASSERT(!structure->isUncacheableDictionary()); |
| ASSERT(structure->isObject()); |
| |
| offset = invalidOffset; |
| |
| if (structure->hasBeenDictionary()) |
| return nullptr; |
| |
| if (Structure* existingTransition = structure->m_transitionTable.get(propertyName.uid(), attributes, TransitionKind::PropertyDeletion)) { |
| validateOffset(existingTransition->transitionOffset(), existingTransition->inlineCapacity()); |
| offset = existingTransition->transitionOffset(); |
| return existingTransition; |
| } |
| |
| return nullptr; |
| } |
| |
| Structure* Structure::removePropertyTransitionFromExistingStructure(Structure* structure, PropertyName propertyName, PropertyOffset& offset) |
| { |
| ASSERT(!isCompilationThread()); |
| unsigned attributes = 0; |
| if (structure->getConcurrently(propertyName.uid(), attributes) == invalidOffset) |
| return nullptr; |
| return removePropertyTransitionFromExistingStructureImpl(structure, propertyName, attributes, offset); |
| } |
| |
| Structure* Structure::removePropertyTransitionFromExistingStructureConcurrently(Structure* structure, PropertyName propertyName, PropertyOffset& offset) |
| { |
| unsigned attributes = 0; |
| if (structure->getConcurrently(propertyName.uid(), attributes) == invalidOffset) |
| return nullptr; |
| ConcurrentJSLocker locker(structure->m_lock); |
| return removePropertyTransitionFromExistingStructureImpl(structure, propertyName, attributes, offset); |
| } |
| |
| Structure* Structure::removeNewPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, PropertyOffset& offset, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| ASSERT(!isCompilationThread()); |
| ASSERT(!structure->isUncacheableDictionary()); |
| ASSERT(structure->isObject()); |
| ASSERT(!Structure::removePropertyTransitionFromExistingStructure(structure, propertyName, offset)); |
| ASSERT(structure->getConcurrently(propertyName.uid()) != invalidOffset); |
| |
| if (structure->transitionCountHasOverflowed()) { |
| ASSERT(!isCopyOnWrite(structure->indexingMode())); |
| Structure* transition = toUncacheableDictionaryTransition(vm, structure, deferred); |
| ASSERT(structure != transition); |
| offset = transition->remove(vm, propertyName); |
| return transition; |
| } |
| |
| Structure* transition = create(vm, structure, deferred); |
| transition->m_cachedPrototypeChain.setMayBeNull(vm, transition, structure->m_cachedPrototypeChain.get()); |
| |
| // While we are deleting the property, we need to make sure the table is not cleared. |
| { |
| ConcurrentJSLocker locker(transition->m_lock); |
| transition->setProtectPropertyTableWhileTransitioning(true); |
| } |
| |
| transition->m_blob.setIndexingModeIncludingHistory(structure->indexingModeIncludingHistory() & ~CopyOnWrite); |
| transition->m_transitionPropertyName = propertyName.uid(); |
| transition->setTransitionKind(TransitionKind::PropertyDeletion); |
| transition->setPropertyTable(vm, structure->takePropertyTableOrCloneIfPinned(vm)); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| |
| offset = transition->remove(vm, propertyName); |
| ASSERT(offset != invalidOffset); |
| transition->setTransitionOffset(vm, offset); |
| |
| // Now that everything is fine with the new structure's bookkeeping, the GC is free to blow the |
| // table away if it wants. We can now rebuild it fine. |
| WTF::storeStoreFence(); |
| transition->setProtectPropertyTableWhileTransitioning(false); |
| |
| checkOffset(transition->transitionOffset(), transition->inlineCapacity()); |
| if (!structure->hasBeenDictionary()) { |
| GCSafeConcurrentJSLocker locker(structure->m_lock, vm); |
| structure->m_transitionTable.add(vm, transition); |
| } |
| transition->checkOffsetConsistency(); |
| structure->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| Structure* Structure::changePrototypeTransition(VM& vm, Structure* structure, JSValue prototype, DeferredStructureTransitionWatchpointFire& deferred) |
| { |
| ASSERT(isValidPrototype(prototype)); |
| |
| DeferGC deferGC(vm); |
| Structure* transition = create(vm, structure, &deferred); |
| |
| transition->m_prototype.set(vm, transition, prototype); |
| |
| PropertyTable* table = structure->copyPropertyTableForPinning(vm); |
| transition->pin(Locker { transition->m_lock }, vm, table); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| |
| transition->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| Structure* Structure::attributeChangeTransitionToExistingStructure(Structure* structure, PropertyName propertyName, unsigned attributes, PropertyOffset& offset) |
| { |
| ASSERT(structure->isObject()); |
| |
| offset = invalidOffset; |
| |
| if (structure->hasBeenDictionary()) |
| return nullptr; |
| |
| if (Structure* existingTransition = structure->m_transitionTable.get(propertyName.uid(), attributes, TransitionKind::PropertyAttributeChange)) { |
| validateOffset(existingTransition->transitionOffset(), existingTransition->inlineCapacity()); |
| offset = existingTransition->transitionOffset(); |
| return existingTransition; |
| } |
| |
| return nullptr; |
| } |
| |
| Structure* Structure::attributeChangeTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| if (structure->isUncacheableDictionary()) { |
| structure->attributeChangeWithoutTransition(vm, propertyName, attributes, [](const GCSafeConcurrentJSLocker&, PropertyOffset, PropertyOffset) { }); |
| structure->checkOffsetConsistency(); |
| return structure; |
| } |
| |
| ASSERT(!structure->isUncacheableDictionary()); |
| PropertyOffset offset = invalidOffset; |
| if (Structure* existingTransition = attributeChangeTransitionToExistingStructure(structure, propertyName, attributes, offset)) { |
| validateOffset(existingTransition->transitionOffset(), existingTransition->inlineCapacity()); |
| existingTransition->checkOffsetConsistency(); |
| return existingTransition; |
| } |
| |
| if (structure->transitionCountHasOverflowed()) { |
| ASSERT(!isCopyOnWrite(structure->indexingMode())); |
| Structure* transition = toUncacheableDictionaryTransition(vm, structure, deferred); |
| ASSERT(structure != transition); |
| transition->attributeChange(vm, propertyName, attributes); |
| return transition; |
| } |
| |
| // Even if the current structure is dictionary, we should perform transition since this changes attributes of existing properties to keep |
| // structure still cacheable. |
| Structure* transition = create(vm, structure); |
| transition->m_cachedPrototypeChain.setMayBeNull(vm, transition, structure->m_cachedPrototypeChain.get()); |
| |
| { |
| ConcurrentJSLocker locker(transition->m_lock); |
| transition->setProtectPropertyTableWhileTransitioning(true); |
| } |
| |
| transition->m_blob.setIndexingModeIncludingHistory(structure->indexingModeIncludingHistory() & ~CopyOnWrite); |
| transition->m_transitionPropertyName = propertyName.uid(); |
| transition->setTransitionPropertyAttributes(attributes); |
| transition->setTransitionKind(TransitionKind::PropertyAttributeChange); |
| transition->setPropertyTable(vm, structure->takePropertyTableOrCloneIfPinned(vm)); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| |
| offset = transition->attributeChange(vm, propertyName, attributes); |
| transition->setTransitionOffset(vm, offset); |
| |
| // Now that everything is fine with the new structure's bookkeeping, the GC is free to blow the |
| // table away if it wants. We can now rebuild it fine. |
| WTF::storeStoreFence(); |
| transition->setProtectPropertyTableWhileTransitioning(false); |
| |
| checkOffset(transition->transitionOffset(), transition->inlineCapacity()); |
| if (!structure->hasBeenDictionary()) { |
| GCSafeConcurrentJSLocker locker(structure->m_lock, vm); |
| structure->m_transitionTable.add(vm, transition); |
| } |
| transition->checkOffsetConsistency(); |
| structure->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| Structure* Structure::toDictionaryTransition(VM& vm, Structure* structure, DictionaryKind kind, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| ASSERT(!structure->isUncacheableDictionary()); |
| DeferGC deferGC(vm); |
| |
| Structure* transition = create(vm, structure, deferred); |
| |
| PropertyTable* table = structure->copyPropertyTableForPinning(vm); |
| transition->pin(Locker { transition->m_lock }, vm, table); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| transition->setDictionaryKind(kind); |
| transition->setHasBeenDictionary(true); |
| |
| transition->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| Structure* Structure::toCacheableDictionaryTransition(VM& vm, Structure* structure, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| return toDictionaryTransition(vm, structure, CachedDictionaryKind, deferred); |
| } |
| |
| Structure* Structure::toUncacheableDictionaryTransition(VM& vm, Structure* structure, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| return toDictionaryTransition(vm, structure, UncachedDictionaryKind, deferred); |
| } |
| |
| Structure* Structure::sealTransition(VM& vm, Structure* structure) |
| { |
| return nonPropertyTransition(vm, structure, TransitionKind::Seal); |
| } |
| |
| Structure* Structure::freezeTransition(VM& vm, Structure* structure) |
| { |
| return nonPropertyTransition(vm, structure, TransitionKind::Freeze); |
| } |
| |
| Structure* Structure::preventExtensionsTransition(VM& vm, Structure* structure) |
| { |
| return nonPropertyTransition(vm, structure, TransitionKind::PreventExtensions); |
| } |
| |
| PropertyTable* Structure::takePropertyTableOrCloneIfPinned(VM& vm) |
| { |
| // This must always return a property table. It can't return null. |
| PropertyTable* result = propertyTableOrNull(); |
| if (result) { |
| if (isPinnedPropertyTable()) |
| return result->copy(vm, result->size() + 1); |
| ConcurrentJSLocker locker(m_lock); |
| setPropertyTable(vm, nullptr); |
| return result; |
| } |
| bool setPropertyTable = false; |
| return materializePropertyTable(vm, setPropertyTable); |
| } |
| |
| Structure* Structure::nonPropertyTransitionSlow(VM& vm, Structure* structure, TransitionKind transitionKind) |
| { |
| IndexingType indexingModeIncludingHistory = newIndexingType(structure->indexingModeIncludingHistory(), transitionKind); |
| |
| if (!structure->isDictionary()) { |
| if (Structure* existingTransition = structure->m_transitionTable.get(nullptr, 0, transitionKind)) { |
| ASSERT(existingTransition->transitionKind() == transitionKind); |
| ASSERT(existingTransition->indexingModeIncludingHistory() == indexingModeIncludingHistory); |
| return existingTransition; |
| } |
| } |
| |
| DeferGC deferGC(vm); |
| |
| Structure* transition = create(vm, structure); |
| transition->setTransitionKind(transitionKind); |
| transition->m_blob.setIndexingModeIncludingHistory(indexingModeIncludingHistory); |
| |
| 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. |
| |
| PropertyTable* table = structure->copyPropertyTableForPinning(vm); |
| transition->pinForCaching(Locker { transition->m_lock }, vm, table); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| |
| table = transition->propertyTableOrNull(); |
| RELEASE_ASSERT(table); |
| for (auto& entry : *table) { |
| if (setsDontDeleteOnAllProperties(transitionKind)) |
| entry.attributes |= static_cast<unsigned>(PropertyAttribute::DontDelete); |
| if (setsReadOnlyOnNonAccessorProperties(transitionKind) && !(entry.attributes & PropertyAttribute::Accessor)) |
| entry.attributes |= static_cast<unsigned>(PropertyAttribute::ReadOnly); |
| } |
| } else { |
| transition->setPropertyTable(vm, structure->takePropertyTableOrCloneIfPinned(vm)); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| checkOffset(transition->maxOffset(), transition->inlineCapacity()); |
| } |
| |
| if (setsReadOnlyOnNonAccessorProperties(transitionKind) |
| && !transition->propertyTableOrNull()->isEmpty()) |
| transition->setHasReadOnlyOrGetterSetterPropertiesExcludingProto(true); |
| |
| if (structure->isDictionary()) { |
| PropertyTable* table = transition->ensurePropertyTable(vm); |
| transition->pin(Locker { transition->m_lock }, vm, table); |
| } else { |
| Locker locker { structure->m_lock }; |
| structure->m_transitionTable.add(vm, transition); |
| } |
| |
| transition->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| // In future we may want to cache this property. |
| bool Structure::isSealed(VM& vm) |
| { |
| if (isStructureExtensible()) |
| return false; |
| |
| PropertyTable* table = ensurePropertyTableIfNotEmpty(vm); |
| if (!table) |
| return true; |
| |
| PropertyTable::iterator end = table->end(); |
| for (PropertyTable::iterator iter = table->begin(); iter != end; ++iter) { |
| if ((iter->attributes & PropertyAttribute::DontDelete) != static_cast<unsigned>(PropertyAttribute::DontDelete)) |
| return false; |
| } |
| return true; |
| } |
| |
| // In future we may want to cache this property. |
| bool Structure::isFrozen(VM& vm) |
| { |
| if (isStructureExtensible()) |
| return false; |
| |
| PropertyTable* table = ensurePropertyTableIfNotEmpty(vm); |
| if (!table) |
| return true; |
| |
| PropertyTable::iterator end = table->end(); |
| for (PropertyTable::iterator iter = table->begin(); iter != end; ++iter) { |
| if (!(iter->attributes & PropertyAttribute::DontDelete)) |
| return false; |
| if (!(iter->attributes & (PropertyAttribute::ReadOnly | PropertyAttribute::Accessor))) |
| return false; |
| } |
| return true; |
| } |
| |
| Structure* Structure::flattenDictionaryStructure(VM& vm, JSObject* object) |
| { |
| checkOffsetConsistency(); |
| ASSERT(isDictionary()); |
| ASSERT(object->structure(vm) == this); |
| |
| GCSafeConcurrentJSLocker locker(m_lock, vm); |
| |
| object->setStructureIDDirectly(nuke(id())); |
| WTF::storeStoreFence(); |
| |
| size_t beforeOutOfLineCapacity = this->outOfLineCapacity(); |
| if (isUncacheableDictionary()) { |
| PropertyTable* table = propertyTableOrNull(); |
| ASSERT(table); |
| |
| size_t propertyCount = table->size(); |
| |
| // Holds our values compacted by insertion order. |
| Vector<JSValue> values(propertyCount); |
| |
| // Copies out our values from their hashed locations, compacting property table offsets as we go. |
| unsigned i = 0; |
| PropertyTable::iterator end = table->end(); |
| auto offset = invalidOffset; |
| for (PropertyTable::iterator iter = table->begin(); iter != end; ++iter, ++i) { |
| values[i] = object->getDirect(iter->offset); |
| offset = iter->offset = offsetForPropertyNumber(i, m_inlineCapacity); |
| } |
| setMaxOffset(vm, offset); |
| ASSERT(transitionOffset() == invalidOffset); |
| |
| // Copies in our values to their compacted locations. |
| for (unsigned i = 0; i < propertyCount; i++) |
| object->putDirect(vm, offsetForPropertyNumber(i, m_inlineCapacity), values[i]); |
| |
| table->clearDeletedOffsets(); |
| |
| // We need to zero our unused property space; otherwise the GC might see a |
| // stale pointer when we add properties in the future. |
| gcSafeZeroMemory( |
| object->inlineStorageUnsafe() + inlineSize(), |
| (inlineCapacity() - inlineSize()) * sizeof(EncodedJSValue)); |
| |
| Butterfly* butterfly = object->butterfly(); |
| size_t preCapacity = butterfly->indexingHeader()->preCapacity(this); |
| void* base = butterfly->base(preCapacity, beforeOutOfLineCapacity); |
| void* startOfPropertyStorageSlots = reinterpret_cast<EncodedJSValue*>(base) + preCapacity; |
| gcSafeZeroMemory(static_cast<JSValue*>(startOfPropertyStorageSlots), (beforeOutOfLineCapacity - outOfLineSize()) * sizeof(EncodedJSValue)); |
| checkOffsetConsistency(); |
| } |
| |
| setDictionaryKind(NoneDictionaryKind); |
| setHasBeenFlattenedBefore(true); |
| |
| size_t afterOutOfLineCapacity = this->outOfLineCapacity(); |
| |
| if (object->butterfly() && beforeOutOfLineCapacity != afterOutOfLineCapacity) { |
| ASSERT(beforeOutOfLineCapacity > afterOutOfLineCapacity); |
| // If the object had a Butterfly but after flattening/compacting we no longer have need of it, |
| // we need to zero it out because the collector depends on the Structure to know the size for copying. |
| if (!afterOutOfLineCapacity && !this->hasIndexingHeader(object)) |
| object->setButterfly(vm, nullptr); |
| // If the object was down-sized to the point where the base of the Butterfly is no longer within the |
| // first CopiedBlock::blockSize bytes, we'll get the wrong answer if we try to mask the base back to |
| // the CopiedBlock header. To prevent this case we need to memmove the Butterfly down. |
| else |
| object->shiftButterflyAfterFlattening(locker, vm, this, afterOutOfLineCapacity); |
| } |
| |
| WTF::storeStoreFence(); |
| object->setStructureIDDirectly(id()); |
| |
| // We need to do a writebarrier here because the GC thread might be scanning the butterfly while |
| // we are shuffling properties around. See: https://bugs.webkit.org/show_bug.cgi?id=166989 |
| vm.writeBarrier(object); |
| |
| return this; |
| } |
| |
| void Structure::pin(const AbstractLocker&, VM& vm, PropertyTable* table) |
| { |
| setIsPinnedPropertyTable(true); |
| setPropertyTable(vm, table); |
| clearPreviousID(); |
| m_transitionPropertyName = nullptr; |
| } |
| |
| void Structure::pinForCaching(const AbstractLocker&, VM& vm, PropertyTable* table) |
| { |
| setIsPinnedPropertyTable(true); |
| setPropertyTable(vm, table); |
| m_transitionPropertyName = nullptr; |
| } |
| |
| void Structure::allocateRareData(VM& vm) |
| { |
| ASSERT(!hasRareData()); |
| StructureRareData* rareData = StructureRareData::create(vm, previousID()); |
| WTF::storeStoreFence(); |
| m_previousOrRareData.set(vm, this, rareData); |
| ASSERT(hasRareData()); |
| } |
| |
| WatchpointSet* Structure::ensurePropertyReplacementWatchpointSet(VM& vm, PropertyOffset offset) |
| { |
| ASSERT(!isUncacheableDictionary()); |
| |
| // In some places it's convenient to call this with an invalid offset. So, we do the check here. |
| if (!isValidOffset(offset)) |
| return nullptr; |
| |
| if (!hasRareData()) |
| allocateRareData(vm); |
| ConcurrentJSLocker locker(m_lock); |
| StructureRareData* rareData = this->rareData(); |
| auto result = rareData->m_replacementWatchpointSets.add(offset, nullptr); |
| if (result.isNewEntry) |
| result.iterator->value = WatchpointSet::create(IsWatched); |
| return result.iterator->value.get(); |
| } |
| |
| void Structure::startWatchingPropertyForReplacements(VM& vm, PropertyName propertyName) |
| { |
| ASSERT(!isUncacheableDictionary()); |
| |
| startWatchingPropertyForReplacements(vm, get(vm, propertyName)); |
| } |
| |
| void Structure::didCachePropertyReplacement(VM& vm, PropertyOffset offset) |
| { |
| RELEASE_ASSERT(isValidOffset(offset)); |
| ensurePropertyReplacementWatchpointSet(vm, offset)->fireAll(vm, "Did cache property replacement"); |
| } |
| |
| void Structure::startWatchingInternalProperties(VM& vm) |
| { |
| if (!isUncacheableDictionary()) { |
| startWatchingPropertyForReplacements(vm, vm.propertyNames->toString); |
| startWatchingPropertyForReplacements(vm, vm.propertyNames->valueOf); |
| } |
| setDidWatchInternalProperties(true); |
| } |
| |
| #if DUMP_PROPERTYMAP_STATS |
| |
| PropertyTableStats* propertyTableStats = 0; |
| |
| struct PropertyTableStatisticsExitLogger { |
| PropertyTableStatisticsExitLogger(); |
| ~PropertyTableStatisticsExitLogger(); |
| }; |
| |
| DEFINE_GLOBAL_FOR_LOGGING(PropertyTableStatisticsExitLogger, logger, { }); |
| |
| PropertyTableStatisticsExitLogger::PropertyTableStatisticsExitLogger() |
| { |
| propertyTableStats = adoptPtr(new PropertyTableStats()).leakPtr(); |
| } |
| |
| PropertyTableStatisticsExitLogger::~PropertyTableStatisticsExitLogger() |
| { |
| unsigned finds = propertyTableStats->numFinds; |
| unsigned collisions = propertyTableStats->numCollisions; |
| dataLogF("\nJSC::PropertyMap statistics for process %d\n\n", getCurrentProcessID()); |
| dataLogF("%d finds\n", finds); |
| dataLogF("%d collisions (%.1f%%)\n", collisions, 100.0 * collisions / finds); |
| dataLogF("%d lookups\n", propertyTableStats->numLookups.load()); |
| dataLogF("%d lookup probings\n", propertyTableStats->numLookupProbing.load()); |
| dataLogF("%d adds\n", propertyTableStats->numAdds.load()); |
| dataLogF("%d removes\n", propertyTableStats->numRemoves.load()); |
| dataLogF("%d rehashes\n", propertyTableStats->numRehashes.load()); |
| dataLogF("%d reinserts\n", propertyTableStats->numReinserts.load()); |
| } |
| |
| #endif |
| |
| PropertyTable* Structure::copyPropertyTableForPinning(VM& vm) |
| { |
| if (PropertyTable* table = propertyTableOrNull()) |
| return PropertyTable::clone(vm, *table); |
| bool setPropertyTable = false; |
| return materializePropertyTable(vm, setPropertyTable); |
| } |
| |
| PropertyOffset Structure::getConcurrently(UniquedStringImpl* uid, unsigned& attributes) |
| { |
| Vector<Structure*, 8> structures; |
| Structure* tableStructure; |
| PropertyTable* table; |
| |
| bool didFindStructure = findStructuresAndMapForMaterialization(structures, tableStructure, table); |
| |
| for (auto* structure : structures) { |
| if (!structure->m_transitionPropertyName) |
| continue; |
| |
| switch (structure->transitionKind()) { |
| case TransitionKind::PropertyAddition: |
| case TransitionKind::PropertyAttributeChange: |
| break; |
| case TransitionKind::PropertyDeletion: |
| if (structure->m_transitionPropertyName.get() == uid) { |
| if (didFindStructure) { |
| assertIsHeld(tableStructure->m_lock); // Sadly Clang needs some help here. |
| tableStructure->m_lock.unlock(); |
| } |
| return invalidOffset; |
| } |
| continue; |
| case TransitionKind::SetBrand: |
| continue; |
| default: |
| ASSERT_NOT_REACHED(); |
| break; |
| } |
| |
| if (structure->m_transitionPropertyName.get() == uid) { |
| PropertyOffset result = structure->transitionOffset(); |
| attributes = structure->transitionPropertyAttributes(); |
| if (didFindStructure) { |
| assertIsHeld(tableStructure->m_lock); // Sadly Clang needs some help here. |
| tableStructure->m_lock.unlock(); |
| } |
| return result; |
| } |
| } |
| |
| PropertyOffset result = invalidOffset; |
| |
| if (didFindStructure) { |
| assertIsHeld(tableStructure->m_lock); // Sadly Clang needs some help here. |
| // Because uid is UniquedStringImpl, it is guaranteed that the hash is already computed. |
| // So we can use PropertyTable::get even from the concurrent compilers. |
| if (auto* entry = table->get(uid)) { |
| result = entry->offset; |
| attributes = entry->attributes; |
| } |
| tableStructure->m_lock.unlock(); |
| } |
| |
| return result; |
| } |
| |
| Vector<PropertyMapEntry> Structure::getPropertiesConcurrently() |
| { |
| Vector<PropertyMapEntry> result; |
| |
| forEachPropertyConcurrently( |
| [&] (const PropertyMapEntry& entry) -> bool { |
| result.append(entry); |
| return true; |
| }); |
| |
| return result; |
| } |
| |
| PropertyOffset Structure::add(VM& vm, PropertyName propertyName, unsigned attributes) |
| { |
| return add<ShouldPin::No>( |
| vm, propertyName, attributes, |
| [this, &vm] (const GCSafeConcurrentJSLocker&, PropertyOffset, PropertyOffset newMaxOffset) { |
| setMaxOffset(vm, newMaxOffset); |
| }); |
| } |
| |
| PropertyOffset Structure::remove(VM& vm, PropertyName propertyName) |
| { |
| return remove<ShouldPin::No>(vm, propertyName, [this, &vm] (const GCSafeConcurrentJSLocker&, PropertyOffset, PropertyOffset newMaxOffset) { |
| setMaxOffset(vm, newMaxOffset); |
| }); |
| } |
| |
| PropertyOffset Structure::attributeChange(VM& vm, PropertyName propertyName, unsigned attributes) |
| { |
| return attributeChange<ShouldPin::No>( |
| vm, propertyName, attributes, |
| [this, &vm] (const GCSafeConcurrentJSLocker&, PropertyOffset, PropertyOffset newMaxOffset) { |
| setMaxOffset(vm, newMaxOffset); |
| }); |
| } |
| |
| void Structure::getPropertyNamesFromStructure(VM& vm, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode) |
| { |
| PropertyTable* table = ensurePropertyTableIfNotEmpty(vm); |
| if (!table) |
| return; |
| |
| bool knownUnique = propertyNames.canAddKnownUniqueForStructure(); |
| bool foundSymbol = false; |
| |
| auto checkDontEnumAndAdd = [&](PropertyTable::iterator iter) { |
| if (mode == DontEnumPropertiesMode::Include || !(iter->attributes & PropertyAttribute::DontEnum)) { |
| if (knownUnique) |
| propertyNames.addUnchecked(iter->key); |
| else |
| propertyNames.add(iter->key); |
| } |
| }; |
| |
| PropertyTable::iterator end = table->end(); |
| for (PropertyTable::iterator iter = table->begin(); iter != end; ++iter) { |
| ASSERT(!isQuickPropertyAccessAllowedForEnumeration() || !(iter->attributes & PropertyAttribute::DontEnum)); |
| ASSERT(!isQuickPropertyAccessAllowedForEnumeration() || !iter->key->isSymbol()); |
| if (iter->key->isSymbol()) { |
| foundSymbol = true; |
| if (propertyNames.propertyNameMode() != PropertyNameMode::Symbols) |
| continue; |
| } |
| checkDontEnumAndAdd(iter); |
| } |
| |
| if (foundSymbol && propertyNames.propertyNameMode() == PropertyNameMode::StringsAndSymbols) { |
| // To ensure the order defined in the spec, we append symbols at the last elements of keys. |
| // https://tc39.es/ecma262/#sec-ordinaryownpropertykeys |
| for (PropertyTable::iterator iter = table->begin(); iter != end; ++iter) { |
| if (iter->key->isSymbol()) |
| checkDontEnumAndAdd(iter); |
| } |
| } |
| } |
| |
| void StructureFireDetail::dump(PrintStream& out) const |
| { |
| out.print("Structure transition from ", *m_structure); |
| } |
| |
| DeferredStructureTransitionWatchpointFire::DeferredStructureTransitionWatchpointFire(VM& vm, Structure* structure) |
| : DeferredWatchpointFire(vm) |
| , m_structure(structure) |
| { |
| } |
| |
| DeferredStructureTransitionWatchpointFire::~DeferredStructureTransitionWatchpointFire() |
| { |
| fireAll(); |
| } |
| |
| void DeferredStructureTransitionWatchpointFire::dump(PrintStream& out) const |
| { |
| out.print("Structure transition from ", *m_structure); |
| } |
| |
| void Structure::didTransitionFromThisStructure(DeferredStructureTransitionWatchpointFire* deferred) const |
| { |
| // If the structure is being watched, and this is the kind of structure that the DFG would |
| // like to watch, then make sure to note for all future versions of this structure that it's |
| // unwise to watch it. |
| if (m_transitionWatchpointSet.isBeingWatched()) |
| const_cast<Structure*>(this)->setTransitionWatchpointIsLikelyToBeFired(true); |
| |
| if (deferred) { |
| ASSERT(deferred->structure() == this); |
| m_transitionWatchpointSet.fireAll(vm(), deferred); |
| } else |
| m_transitionWatchpointSet.fireAll(vm(), StructureFireDetail(this)); |
| } |
| |
| template<typename Visitor> |
| void Structure::visitChildrenImpl(JSCell* cell, Visitor& visitor) |
| { |
| Structure* thisObject = jsCast<Structure*>(cell); |
| ASSERT_GC_OBJECT_INHERITS(thisObject, info()); |
| |
| Base::visitChildren(thisObject, visitor); |
| |
| ConcurrentJSLocker locker(thisObject->m_lock); |
| |
| visitor.append(thisObject->m_globalObject); |
| if (!thisObject->isObject()) { |
| // We do not need to clear JSPropertyNameEnumerator since it is never cached for non-object Structure. |
| // We do not have code clearing JSPropertyNameEnumerator since this function can be called concurrently. |
| thisObject->m_cachedPrototypeChain.clear(); |
| #if ASSERT_ENABLED |
| if (auto* rareData = thisObject->tryRareData()) |
| ASSERT(!rareData->cachedPropertyNameEnumerator()); |
| #endif |
| } else { |
| visitor.append(thisObject->m_prototype); |
| visitor.append(thisObject->m_cachedPrototypeChain); |
| } |
| visitor.append(thisObject->m_previousOrRareData); |
| |
| if (thisObject->isPinnedPropertyTable() || thisObject->protectPropertyTableWhileTransitioning()) { |
| // NOTE: This can interleave in pin(), in which case it may see a null property table. |
| // That's fine, because then the barrier will fire and we will scan this again. |
| visitor.append(thisObject->m_propertyTableUnsafe); |
| } else if (visitor.vm().isAnalyzingHeap()) |
| visitor.append(thisObject->m_propertyTableUnsafe); |
| else if (thisObject->m_propertyTableUnsafe) |
| thisObject->m_propertyTableUnsafe.clear(); |
| |
| if (thisObject->isBrandedStructure()) |
| BrandedStructure::visitAdditionalChildren(cell, visitor); |
| } |
| |
| DEFINE_VISIT_CHILDREN(Structure); |
| |
| template<typename Visitor> |
| ALWAYS_INLINE bool Structure::isCheapDuringGC(Visitor& visitor) |
| { |
| // FIXME: We could make this even safer by returning false if this structure's property table |
| // has any large property names. |
| // https://bugs.webkit.org/show_bug.cgi?id=157334 |
| |
| return (!m_globalObject || visitor.isMarked(m_globalObject.get())) |
| && (hasPolyProto() || !storedPrototypeObject() || visitor.isMarked(storedPrototypeObject())); |
| } |
| |
| template<typename Visitor> |
| bool Structure::markIfCheap(Visitor& visitor) |
| { |
| if (!isCheapDuringGC(visitor)) |
| return visitor.isMarked(this); |
| |
| visitor.appendUnbarriered(this); |
| return true; |
| } |
| |
| template bool Structure::markIfCheap(AbstractSlotVisitor&); |
| template bool Structure::markIfCheap(SlotVisitor&); |
| |
| Ref<StructureShape> Structure::toStructureShape(JSValue value, bool& sawPolyProtoStructure) |
| { |
| Ref<StructureShape> baseShape = StructureShape::create(); |
| RefPtr<StructureShape> curShape = baseShape.ptr(); |
| Structure* curStructure = this; |
| JSValue curValue = value; |
| sawPolyProtoStructure = false; |
| while (curStructure) { |
| sawPolyProtoStructure |= curStructure->hasPolyProto(); |
| curStructure->forEachPropertyConcurrently( |
| [&] (const PropertyMapEntry& entry) -> bool { |
| if (!PropertyName(entry.key).isPrivateName()) |
| curShape->addProperty(*entry.key); |
| return true; |
| }); |
| |
| if (JSObject* curObject = curValue.getObject()) |
| curShape->setConstructorName(JSObject::calculatedClassName(curObject)); |
| else |
| curShape->setConstructorName(curStructure->classInfo()->className); |
| |
| if (curStructure->isDictionary()) |
| curShape->enterDictionaryMode(); |
| |
| curShape->markAsFinal(); |
| |
| if (!curValue.isObject()) |
| break; |
| |
| JSObject* object = asObject(curValue); |
| JSObject* prototypeObject = object->structure()->storedPrototypeObject(object); |
| if (!prototypeObject) |
| break; |
| |
| auto newShape = StructureShape::create(); |
| curShape->setProto(newShape.copyRef()); |
| curShape = WTFMove(newShape); |
| curValue = prototypeObject; |
| curStructure = prototypeObject->structure(); |
| } |
| |
| return baseShape; |
| } |
| |
| void Structure::dump(PrintStream& out) const |
| { |
| auto* structureID = reinterpret_cast<void*>(id()); |
| out.print(RawPointer(this), ":[", RawPointer(structureID), |
| "/", (uint32_t)(reinterpret_cast<uintptr_t>(structureID)), ", ", |
| classInfo()->className, ", (", inlineSize(), "/", inlineCapacity(), ", ", |
| outOfLineSize(), "/", outOfLineCapacity(), "){"); |
| |
| CommaPrinter comma; |
| |
| const_cast<Structure*>(this)->forEachPropertyConcurrently( |
| [&] (const PropertyMapEntry& entry) -> bool { |
| out.print(comma, entry.key, ":", static_cast<int>(entry.offset)); |
| return true; |
| }); |
| |
| out.print("}, ", IndexingTypeDump(indexingMode())); |
| |
| if (hasPolyProto()) |
| out.print(", PolyProto offset:", knownPolyProtoOffset); |
| else if (m_prototype.get().isCell()) |
| out.print(", Proto:", RawPointer(m_prototype.get().asCell())); |
| |
| switch (dictionaryKind()) { |
| case NoneDictionaryKind: |
| if (hasBeenDictionary()) |
| out.print(", Has been dictionary"); |
| break; |
| case CachedDictionaryKind: |
| out.print(", Dictionary"); |
| break; |
| case UncachedDictionaryKind: |
| out.print(", UncacheableDictionary"); |
| break; |
| } |
| |
| if (transitionWatchpointSetIsStillValid()) |
| out.print(", Leaf"); |
| else if (transitionWatchpointIsLikelyToBeFired()) |
| out.print(", Shady leaf"); |
| |
| if (transitionWatchpointSet().isBeingWatched()) |
| out.print(" (Watched)"); |
| |
| out.print("]"); |
| } |
| |
| void Structure::dumpInContext(PrintStream& out, DumpContext* context) const |
| { |
| if (context) |
| context->structures.dumpBrief(this, out); |
| else |
| dump(out); |
| } |
| |
| void Structure::dumpBrief(PrintStream& out, const CString& string) const |
| { |
| out.print("%", string, ":", classInfo()->className); |
| if (indexingType() & IndexingShapeMask) |
| out.print(",", IndexingTypeDump(indexingType())); |
| } |
| |
| void Structure::dumpContextHeader(PrintStream& out) |
| { |
| out.print("Structures:"); |
| } |
| |
| bool ClassInfo::hasStaticSetterOrReadonlyProperties() const |
| { |
| for (const ClassInfo* ci = this; ci; ci = ci->parentClass) { |
| if (const HashTable* table = ci->staticPropHashTable) { |
| if (table->hasSetterOrReadonlyProperties) |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| void Structure::setCachedPropertyNameEnumerator(VM& vm, JSPropertyNameEnumerator* enumerator, StructureChain* chain) |
| { |
| ASSERT(typeInfo().isObject()); |
| ASSERT(!isDictionary()); |
| if (!hasRareData()) |
| allocateRareData(vm); |
| ASSERT(chain == m_cachedPrototypeChain.get()); |
| rareData()->setCachedPropertyNameEnumerator(vm, this, enumerator, chain); |
| } |
| |
| JSPropertyNameEnumerator* Structure::cachedPropertyNameEnumerator() const |
| { |
| if (!hasRareData()) |
| return nullptr; |
| return rareData()->cachedPropertyNameEnumerator(); |
| } |
| |
| uintptr_t Structure::cachedPropertyNameEnumeratorAndFlag() const |
| { |
| if (!hasRareData()) |
| return 0; |
| return rareData()->cachedPropertyNameEnumeratorAndFlag(); |
| } |
| |
| bool Structure::canCachePropertyNameEnumerator(VM& vm) const |
| { |
| if (!this->canCacheOwnPropertyNames()) |
| return false; |
| |
| StructureChain* structureChain = m_cachedPrototypeChain.get(); |
| ASSERT(structureChain); |
| StructureID* currentStructureID = structureChain->head(); |
| while (true) { |
| StructureID structureID = *currentStructureID; |
| if (!structureID) |
| return true; |
| Structure* structure = vm.getStructure(structureID); |
| if (!structure->canCacheOwnPropertyNames()) |
| return false; |
| currentStructureID++; |
| } |
| |
| ASSERT_NOT_REACHED(); |
| return true; |
| } |
| |
| bool Structure::canAccessPropertiesQuicklyForEnumeration() const |
| { |
| if (!isQuickPropertyAccessAllowedForEnumeration()) |
| return false; |
| if (hasGetterSetterProperties()) |
| return false; |
| if (hasCustomGetterSetterProperties()) |
| return false; |
| if (isUncacheableDictionary()) |
| return false; |
| if (typeInfo().overridesGetOwnPropertyNames()) |
| return false; |
| return true; |
| } |
| |
| auto Structure::findPropertyHashEntry(PropertyName propertyName) const -> std::optional<PropertyHashEntry> |
| { |
| for (const ClassInfo* info = classInfo(); info; info = info->parentClass) { |
| if (const HashTable* propHashTable = info->staticPropHashTable) { |
| if (const HashTableValue* entry = propHashTable->entry(propertyName)) |
| return PropertyHashEntry { propHashTable, entry }; |
| } |
| } |
| return std::nullopt; |
| } |
| |
| Structure* Structure::setBrandTransitionFromExistingStructureImpl(Structure* structure, UniquedStringImpl* brandID) |
| { |
| ASSERT(structure->isObject()); |
| |
| if (structure->hasBeenDictionary()) |
| return nullptr; |
| |
| if (Structure* existingTransition = structure->m_transitionTable.get(brandID, 0, TransitionKind::SetBrand)) |
| return existingTransition; |
| |
| return nullptr; |
| } |
| |
| Structure* Structure::setBrandTransitionFromExistingStructureConcurrently(Structure* structure, UniquedStringImpl* brandID) |
| { |
| ConcurrentJSLocker locker(structure->m_lock); |
| return setBrandTransitionFromExistingStructureImpl(structure, brandID); |
| } |
| |
| Structure* Structure::setBrandTransition(VM& vm, Structure* structure, Symbol* brand, DeferredStructureTransitionWatchpointFire* deferred) |
| { |
| Structure* existingTransition = setBrandTransitionFromExistingStructureImpl(structure, &brand->uid()); |
| if (existingTransition) |
| return existingTransition; |
| |
| Structure* transition = BrandedStructure::create(vm, structure, &brand->uid(), deferred); |
| transition->setTransitionKind(TransitionKind::SetBrand); |
| |
| transition->m_cachedPrototypeChain.setMayBeNull(vm, transition, structure->m_cachedPrototypeChain.get()); |
| transition->m_blob.setIndexingModeIncludingHistory(structure->indexingModeIncludingHistory()); |
| transition->m_transitionPropertyName = &brand->uid(); |
| transition->setTransitionPropertyAttributes(0); |
| transition->setPropertyTable(vm, structure->takePropertyTableOrCloneIfPinned(vm)); |
| transition->setMaxOffset(vm, structure->maxOffset()); |
| checkOffset(transition->maxOffset(), transition->inlineCapacity()); |
| |
| if (structure->isDictionary()) { |
| PropertyTable* table = transition->ensurePropertyTable(vm); |
| transition->pin(Locker { transition->m_lock }, vm, table); |
| } else { |
| Locker locker { structure->m_lock }; |
| structure->m_transitionTable.add(vm, transition); |
| } |
| |
| transition->checkOffsetConsistency(); |
| return transition; |
| } |
| |
| } // namespace JSC |
