/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- * vim: set ts=8 sts=2 et sw=2 tw=80: * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef vm_Iteration_h #define vm_Iteration_h /* * JavaScript iterators. */ #include "mozilla/ArrayUtils.h" #include "mozilla/MemoryReporting.h" #include "builtin/SelfHostingDefines.h" #include "gc/Barrier.h" #include "vm/NativeObject.h" #include "vm/TypedArrayObject.h" /* * [SMDOC] For-in enumeration * * A for-in loop in JS iterates over the string-valued, enumerable * property keys of an object and its prototype chain. The order in * which keys appear is specified to the extent that implementations * historically agreed, and implementation-defined beyond that. See * https://tc39.es/ecma262/#sec-enumerate-object-properties for the * gory details. Each key appears only once in the enumeration. * * We enumerate properties using PropertyEnumerator, which creates an * ordered list of PropertyKeys, using ShapePropertyIter for native * objects and calling enumerate hooks where necessary. This list is * used to create a NativeIterator, which contains (among other * things) a trailing array of strings representing the property keys * of the object, and a cursor pointing into that array. This * NativeIterator is wrapped in a PropertyIteratorObject, which is * pushed by JSOp::Iter and used by JSOp::MoreIter and JSOp::EndIter. * * While active, a NativeIterator is registered in a doubly linked * list, rooted in the compartment. When any property is deleted from * an object, this list is used to remove the deleted property from * any active enumerations. See SuppressDeletedProperty. This slows * down deletion but speeds up enumeration, which is generally a good * tradeoff. * * In many cases, objects with the same shape will have the same set * of property keys. (The most common exception is objects with dense * elements, which can be added or removed without changing the shape * of the object.) In such cases, we can reuse an existing iterator by * storing a pointer to the PropertyIteratorObject in the shape's * |cache_| pointer. Before reusing an iterator, we have to verify * that the prototype chain has not changed and no dense elements have * been added, which is done by storing a trailing array of prototype * shapes in the NativeIterator and comparing it against the shapes of * the prototype chain. * * One of the most frequent uses of for-in loops is in loops that look * like this, which iterate over each property of an object and do * something with those values: * for (var key in obj) { * if (obj.hasOwnProperty(key)) { * doSomethingWith(obj[key]); * } * } * Most objects don't have any enumerable properties on the prototype * chain. In such cases, we can speed up property access inside the * loop by precomputing some information and storing it in the * iterator. When we see a pattern like this in Ion, we generate a * call to GetIteratorWithIndices instead of GetIterator. In this * case, in addition to the list of property keys, PropertyEnumerator * will try to generate a list of corresponding PropertyIndex values, * which represent the location of the own property key in the object * (fixed slot/dynamic slot/dense element + offset). This list will be * stored in NativeIterator as yet another trailing array. When * present, it can be used by Ion code to speed up property access * inside for-in loops. See OptimizeIteratorIndices in * IonAnalysis.cpp. */ namespace js { class ArrayObject; class PlainObject; class PropertyIteratorObject; // A PropertyIndex stores information about the location of an own data // property in a format that can be stored in a NativeIterator and consumed by // jitcode to access properties without needing to use the megamorphic cache. struct PropertyIndex { private: uint32_t asBits_; public: enum class Kind : uint32_t { DynamicSlot, FixedSlot, Element, Invalid }; PropertyIndex(Kind kind, uint32_t index) : asBits_(encode(kind, index)) {} static PropertyIndex Invalid() { return PropertyIndex(Kind::Invalid, 0); } static PropertyIndex ForElement(uint32_t index) { return PropertyIndex(Kind::Element, index); } static PropertyIndex ForSlot(NativeObject* obj, uint32_t index) { if (index < obj->numFixedSlots()) { return PropertyIndex(Kind::FixedSlot, index); } else { return PropertyIndex(Kind::DynamicSlot, index - obj->numFixedSlots()); } } static constexpr uint32_t KindBits = 2; static constexpr uint32_t IndexBits = 32 - KindBits; static constexpr uint32_t IndexLimit = 1 << IndexBits; static constexpr uint32_t IndexMask = (1 << IndexBits) - 1; static constexpr uint32_t KindShift = IndexBits; static_assert(NativeObject::MAX_FIXED_SLOTS < IndexLimit); static_assert(NativeObject::MAX_SLOTS_COUNT < IndexLimit); static_assert(NativeObject::MAX_DENSE_ELEMENTS_COUNT < IndexLimit); private: uint32_t encode(Kind kind, uint32_t index) { MOZ_ASSERT(index < IndexLimit); return (uint32_t(kind) << KindShift) | index; } public: Kind kind() const { return Kind(asBits_ >> KindShift); } uint32_t index() const { return asBits_ & IndexMask; } }; using PropertyIndexVector = js::Vector; struct NativeIterator; class NativeIteratorListNode { protected: // While in compartment->enumerators, these form a doubly linked list. NativeIteratorListNode* prev_ = nullptr; NativeIteratorListNode* next_ = nullptr; public: NativeIteratorListNode* prev() { return prev_; } NativeIteratorListNode* next() { return next_; } void setPrev(NativeIteratorListNode* prev) { prev_ = prev; } void setNext(NativeIteratorListNode* next) { next_ = next; } static constexpr size_t offsetOfNext() { return offsetof(NativeIteratorListNode, next_); } static constexpr size_t offsetOfPrev() { return offsetof(NativeIteratorListNode, prev_); } private: NativeIterator* asNativeIterator() { return reinterpret_cast(this); } friend class NativeIteratorListIter; }; class NativeIteratorListHead : public NativeIteratorListNode { private: // Initialize a |Compartment::enumerators| sentinel. NativeIteratorListHead() { prev_ = next_ = this; } friend class JS::Compartment; }; class NativeIteratorListIter { private: NativeIteratorListHead* head_; NativeIteratorListNode* curr_; public: explicit NativeIteratorListIter(NativeIteratorListHead* head) : head_(head), curr_(head->next()) {} bool done() const { return curr_ == head_; } NativeIterator* next() { MOZ_ASSERT(!done()); NativeIterator* result = curr_->asNativeIterator(); curr_ = curr_->next(); return result; } }; // If an object only has own data properties, we can store a list of // PropertyIndex that can be used in Ion to more efficiently access those // properties in cases like `for (var key in obj) { ...obj[key]... }`. enum class NativeIteratorIndices : uint32_t { // The object being iterated does not support indices. Unavailable = 0, // The object being iterated supports indices, but none have been // allocated, because it has not yet been iterated by Ion code that // can use indices-based access. AvailableOnRequest = 1, // The object being iterated had indices allocated, but they were // disabled due to a deleted property. Disabled = 2, // The object being iterated had indices allocated, and they are // still valid. Valid = 3 }; struct NativeIterator : public NativeIteratorListNode { private: // Object being iterated. Non-null except in NativeIterator sentinels, // the empty iterator singleton (for iterating |null| or |undefined|), and // inactive iterators. GCPtr objectBeingIterated_ = {}; // Internal iterator object. const GCPtr iterObj_ = {}; // The end of GCPtrs that appear directly after |this|, as part of an // overall allocation that stores |*this|, shapes, iterated strings, and maybe // indices. Once this has been fully initialized, it also equals the start of // iterated strings. GCPtr* shapesEnd_; // initialized by constructor // The next property, pointing into an array of strings directly after any // GCPtrs that appear directly after |*this|, as part of an overall // allocation that stores |*this|, shapes, iterated strings, and maybe // indices. GCPtr* propertyCursor_; // initialized by constructor // The limit/end of properties to iterate. Once |this| has been fully // initialized, it also equals the start of indices, if indices are present, // or the end of the full allocation storing |*this|, shapes, and strings, if // indices are not present. Beware! This value may change as properties are // deleted from the observed object. GCPtr* propertiesEnd_; // initialized by constructor HashNumber shapesHash_; // initialized by constructor public: // For cacheable native iterators, whether the iterator is currently // active. Not serialized by XDR. struct Flags { // This flag is set when all shapes and properties associated with this // NativeIterator have been initialized, such that |shapesEnd_|, in // addition to being the end of shapes, is also the beginning of // properties. // // This flag is only *not* set when a NativeIterator is in the process // of being constructed. At such time |shapesEnd_| accounts only for // shapes that have been initialized -- potentially none of them. // Instead, |propertyCursor_| is initialized to the ultimate/actual // start of properties and must be used instead of |propertiesBegin()|, // which asserts that this flag is present to guard against misuse. static constexpr uint32_t Initialized = 0x1; // This flag indicates that this NativeIterator is currently being used // to enumerate an object's properties and has not yet been closed. static constexpr uint32_t Active = 0x2; // This flag indicates that the object being enumerated by this // |NativeIterator| had a property deleted from it before it was // visited, forcing the properties array in this to be mutated to // remove it. static constexpr uint32_t HasUnvisitedPropertyDeletion = 0x4; // Whether this is the shared empty iterator object used for iterating over // null/undefined. static constexpr uint32_t IsEmptyIteratorSingleton = 0x8; // If any of these bits are set on a |NativeIterator|, it isn't // currently reusable. (An active |NativeIterator| can't be stolen // *right now*; a |NativeIterator| that's had its properties mutated // can never be reused, because it would give incorrect results.) static constexpr uint32_t NotReusable = Active | HasUnvisitedPropertyDeletion; }; private: static constexpr uint32_t FlagsBits = 4; static constexpr uint32_t IndicesBits = 2; static constexpr uint32_t FlagsMask = (1 << FlagsBits) - 1; static constexpr uint32_t PropCountShift = IndicesBits + FlagsBits; static constexpr uint32_t PropCountBits = 32 - PropCountShift; public: static constexpr uint32_t IndicesShift = FlagsBits; static constexpr uint32_t IndicesMask = ((1 << IndicesBits) - 1) << IndicesShift; static constexpr uint32_t PropCountLimit = 1 << PropCountBits; private: // Stores Flags bits and indices state in the lower bits and the initial // property count above them. uint32_t flagsAndCount_ = 0; #ifdef DEBUG // If true, this iterator may contain indexed properties that came from // objects on the prototype chain. This is used by certain debug assertions. bool maybeHasIndexedPropertiesFromProto_ = false; #endif // END OF PROPERTIES // No further fields appear after here *in NativeIterator*, but this class is // always allocated with space tacked on immediately after |this| to store // shapes p to |shapesEnd_|, iterated property names after that up to // |propertiesEnd_|, and maybe PropertyIndex values up to |indices_end()|. public: /** * Initialize a NativeIterator properly allocated for |props.length()| * properties and |numShapes| shapes. If |indices| is non-null, also * allocates room for |indices.length()| PropertyIndex values. In this case, * |indices.length()| must equal |props.length()|. * * Despite being a constructor, THIS FUNCTION CAN REPORT ERRORS. Users * MUST set |*hadError = false| on entry and consider |*hadError| on return * to mean this function failed. */ NativeIterator(JSContext* cx, Handle propIter, Handle objBeingIterated, HandleIdVector props, bool supportsIndices, PropertyIndexVector* indices, uint32_t numShapes, bool* hadError); JSObject* objectBeingIterated() const { return objectBeingIterated_; } void initObjectBeingIterated(JSObject& obj) { MOZ_ASSERT(!objectBeingIterated_); objectBeingIterated_.init(&obj); } void clearObjectBeingIterated() { MOZ_ASSERT(objectBeingIterated_); objectBeingIterated_ = nullptr; } GCPtr* shapesBegin() const { static_assert( alignof(GCPtr) <= alignof(NativeIterator), "NativeIterator must be aligned to begin storing " "GCPtrs immediately after it with no required padding"); const NativeIterator* immediatelyAfter = this + 1; auto* afterNonConst = const_cast(immediatelyAfter); return reinterpret_cast*>(afterNonConst); } GCPtr* shapesEnd() const { return shapesEnd_; } uint32_t shapeCount() const { return mozilla::PointerRangeSize(shapesBegin(), shapesEnd()); } GCPtr* propertiesBegin() const { static_assert( alignof(GCPtr) >= alignof(GCPtr), "GCPtrs for properties must be able to appear " "directly after any GCPtrs after this NativeIterator, " "with no padding space required for correct alignment"); static_assert( alignof(NativeIterator) >= alignof(GCPtr), "GCPtrs for properties must be able to appear " "directly after this NativeIterator when no GCPtrs are " "present, with no padding space required for correct " "alignment"); // We *could* just check the assertion below if we wanted, but the // incompletely-initialized NativeIterator case matters for so little // code that we prefer not imposing the condition-check on every single // user. MOZ_ASSERT(isInitialized(), "NativeIterator must be initialized, or else |shapesEnd_| " "isn't necessarily the start of properties and instead " "|propertyCursor_| is"); return reinterpret_cast*>(shapesEnd_); } GCPtr* propertiesEnd() const { return propertiesEnd_; } GCPtr* nextProperty() const { return propertyCursor_; } PropertyIndex* indicesBegin() const { // PropertyIndex must be able to be appear directly after the properties // array, with no padding required for correct alignment. static_assert(alignof(GCPtr) >= alignof(PropertyIndex)); return reinterpret_cast(propertiesEnd_); } PropertyIndex* indicesEnd() const { MOZ_ASSERT(indicesState() == NativeIteratorIndices::Valid); return indicesBegin() + numKeys() * sizeof(PropertyIndex); } MOZ_ALWAYS_INLINE JS::Value nextIteratedValueAndAdvance() { if (propertyCursor_ >= propertiesEnd_) { MOZ_ASSERT(propertyCursor_ == propertiesEnd_); return JS::MagicValue(JS_NO_ITER_VALUE); } JSLinearString* str = *propertyCursor_; incCursor(); return JS::StringValue(str); } void resetPropertyCursorForReuse() { MOZ_ASSERT(isInitialized()); // This function is called unconditionally on IteratorClose, so // unvisited properties might have been deleted, so we can't assert // this NativeIterator is reusable. (Should we not bother resetting // the cursor in that case?) // Note: JIT code inlines |propertyCursor_| resetting when an iterator // ends: see |CodeGenerator::visitIteratorEnd|. propertyCursor_ = propertiesBegin(); } bool previousPropertyWas(JS::Handle str) { MOZ_ASSERT(isInitialized()); return propertyCursor_ > propertiesBegin() && propertyCursor_[-1] == str; } size_t numKeys() const { return mozilla::PointerRangeSize(propertiesBegin(), propertiesEnd()); } void trimLastProperty() { MOZ_ASSERT(isInitialized()); propertiesEnd_--; // This invokes the pre barrier on this property, since it's no longer // going to be marked, and it ensures that any existing remembered set // entry will be dropped. *propertiesEnd_ = nullptr; // Indices are no longer valid. disableIndices(); } JSObject* iterObj() const { return iterObj_; } void incCursor() { MOZ_ASSERT(isInitialized()); propertyCursor_++; } HashNumber shapesHash() const { return shapesHash_; } bool isInitialized() const { return flags() & Flags::Initialized; } size_t allocationSize() const; #ifdef DEBUG void setMaybeHasIndexedPropertiesFromProto() { maybeHasIndexedPropertiesFromProto_ = true; } bool maybeHasIndexedPropertiesFromProto() const { return maybeHasIndexedPropertiesFromProto_; } #endif private: uint32_t flags() const { return flagsAndCount_ & FlagsMask; } NativeIteratorIndices indicesState() const { return NativeIteratorIndices((flagsAndCount_ & IndicesMask) >> IndicesShift); } uint32_t initialPropertyCount() const { return flagsAndCount_ >> PropCountShift; } static uint32_t initialFlagsAndCount(uint32_t count) { // No flags are initially set. MOZ_ASSERT(count < PropCountLimit); return count << PropCountShift; } void setFlags(uint32_t flags) { MOZ_ASSERT((flags & ~FlagsMask) == 0); flagsAndCount_ = (flagsAndCount_ & ~FlagsMask) | flags; } void setIndicesState(NativeIteratorIndices indices) { uint32_t indicesBits = uint32_t(indices) << IndicesShift; flagsAndCount_ = (flagsAndCount_ & ~IndicesMask) | indicesBits; } bool indicesAllocated() const { return indicesState() >= NativeIteratorIndices::Disabled; } void markInitialized() { MOZ_ASSERT(flags() == 0); setFlags(Flags::Initialized); } bool isUnlinked() const { return !prev_ && !next_; } public: // Whether this is the shared empty iterator object used for iterating over // null/undefined. bool isEmptyIteratorSingleton() const { // Note: equivalent code is inlined in MacroAssembler::iteratorClose. bool res = flags() & Flags::IsEmptyIteratorSingleton; MOZ_ASSERT_IF( res, flags() == (Flags::Initialized | Flags::IsEmptyIteratorSingleton)); MOZ_ASSERT_IF(res, !objectBeingIterated_); MOZ_ASSERT_IF(res, initialPropertyCount() == 0); MOZ_ASSERT_IF(res, shapeCount() == 0); MOZ_ASSERT_IF(res, isUnlinked()); return res; } void markEmptyIteratorSingleton() { flagsAndCount_ |= Flags::IsEmptyIteratorSingleton; // isEmptyIteratorSingleton() has various debug assertions. MOZ_ASSERT(isEmptyIteratorSingleton()); } bool isActive() const { MOZ_ASSERT(isInitialized()); return flags() & Flags::Active; } void markActive() { MOZ_ASSERT(isInitialized()); MOZ_ASSERT(!isEmptyIteratorSingleton()); flagsAndCount_ |= Flags::Active; } void markInactive() { MOZ_ASSERT(isInitialized()); MOZ_ASSERT(!isEmptyIteratorSingleton()); flagsAndCount_ &= ~Flags::Active; } bool isReusable() const { MOZ_ASSERT(isInitialized()); // Cached NativeIterators are reusable if they're not currently active // and their properties array hasn't been mutated, i.e. if only // |Flags::Initialized| is set. Using |Flags::NotReusable| to test // would also work, but this formulation is safer against memory // corruption. return flags() == Flags::Initialized; } void markHasUnvisitedPropertyDeletion() { MOZ_ASSERT(isInitialized()); MOZ_ASSERT(!isEmptyIteratorSingleton()); flagsAndCount_ |= Flags::HasUnvisitedPropertyDeletion; } bool hasValidIndices() const { return indicesState() == NativeIteratorIndices::Valid; } bool indicesAvailableOnRequest() const { return indicesState() == NativeIteratorIndices::AvailableOnRequest; } // Indicates the native iterator may walk prototype properties. bool mayHavePrototypeProperties() { // If we can use indices for this iterator, we know it doesn't have // prototype properties, and so we use this as a check for prototype // properties. return !hasValidIndices() && !indicesAvailableOnRequest(); } void disableIndices() { // If we have allocated indices, set the state to Disabled. // This will ensure that we don't use them, but we still // free them correctly. if (indicesState() == NativeIteratorIndices::Valid) { setIndicesState(NativeIteratorIndices::Disabled); } } void link(NativeIteratorListNode* other) { MOZ_ASSERT(isInitialized()); // The shared iterator used for for-in with null/undefined is immutable and // shouldn't be linked. MOZ_ASSERT(!isEmptyIteratorSingleton()); // A NativeIterator cannot appear in the enumerator list twice. MOZ_ASSERT(isUnlinked()); setNext(other); setPrev(other->prev()); other->prev()->setNext(this); other->setPrev(this); } void unlink() { MOZ_ASSERT(isInitialized()); MOZ_ASSERT(!isEmptyIteratorSingleton()); next()->setPrev(prev()); prev()->setNext(next()); setNext(nullptr); setPrev(nullptr); } void trace(JSTracer* trc); static constexpr size_t offsetOfObjectBeingIterated() { return offsetof(NativeIterator, objectBeingIterated_); } static constexpr size_t offsetOfShapesEnd() { return offsetof(NativeIterator, shapesEnd_); } static constexpr size_t offsetOfPropertyCursor() { return offsetof(NativeIterator, propertyCursor_); } static constexpr size_t offsetOfPropertiesEnd() { return offsetof(NativeIterator, propertiesEnd_); } static constexpr size_t offsetOfFlagsAndCount() { return offsetof(NativeIterator, flagsAndCount_); } static constexpr size_t offsetOfFirstShape() { // Shapes are stored directly after |this|. return sizeof(NativeIterator); } }; class PropertyIteratorObject : public NativeObject { static const JSClassOps classOps_; enum { IteratorSlot, SlotCount }; public: static const JSClass class_; NativeIterator* getNativeIterator() const { return maybePtrFromReservedSlot(IteratorSlot); } void initNativeIterator(js::NativeIterator* ni) { initReservedSlot(IteratorSlot, PrivateValue(ni)); } size_t sizeOfMisc(mozilla::MallocSizeOf mallocSizeOf) const; static size_t offsetOfIteratorSlot() { return getFixedSlotOffset(IteratorSlot); } private: static void trace(JSTracer* trc, JSObject* obj); static void finalize(JS::GCContext* gcx, JSObject* obj); }; class ArrayIteratorObject : public NativeObject { public: static const JSClass class_; }; ArrayIteratorObject* NewArrayIteratorTemplate(JSContext* cx); ArrayIteratorObject* NewArrayIterator(JSContext* cx); class StringIteratorObject : public NativeObject { public: static const JSClass class_; }; StringIteratorObject* NewStringIteratorTemplate(JSContext* cx); StringIteratorObject* NewStringIterator(JSContext* cx); class RegExpStringIteratorObject : public NativeObject { public: static const JSClass class_; }; RegExpStringIteratorObject* NewRegExpStringIteratorTemplate(JSContext* cx); RegExpStringIteratorObject* NewRegExpStringIterator(JSContext* cx); [[nodiscard]] bool EnumerateProperties(JSContext* cx, HandleObject obj, MutableHandleIdVector props); PropertyIteratorObject* LookupInIteratorCache(JSContext* cx, HandleObject obj); PropertyIteratorObject* LookupInShapeIteratorCache(JSContext* cx, HandleObject obj); PropertyIteratorObject* GetIterator(JSContext* cx, HandleObject obj); PropertyIteratorObject* GetIteratorWithIndices(JSContext* cx, HandleObject obj); PropertyIteratorObject* ValueToIterator(JSContext* cx, HandleValue vp); void CloseIterator(JSObject* obj); bool IteratorCloseForException(JSContext* cx, HandleObject obj); void UnwindIteratorForUncatchableException(JSObject* obj); extern bool SuppressDeletedProperty(JSContext* cx, HandleObject obj, jsid id); extern bool SuppressDeletedElement(JSContext* cx, HandleObject obj, uint32_t index); #ifdef DEBUG extern void AssertDenseElementsNotIterated(NativeObject* obj); #else inline void AssertDenseElementsNotIterated(NativeObject* obj) {} #endif /* * IteratorMore() returns the next iteration value. If no value is available, * MagicValue(JS_NO_ITER_VALUE) is returned. */ inline Value IteratorMore(JSObject* iterobj) { NativeIterator* ni = iterobj->as().getNativeIterator(); return ni->nextIteratedValueAndAdvance(); } /* * Create an object of the form { value: VALUE, done: DONE }. * ES 2017 draft 7.4.7. */ extern PlainObject* CreateIterResultObject(JSContext* cx, HandleValue value, bool done); /* * Global Iterator constructor. * Iterator Helpers proposal 2.1.3. */ class IteratorObject : public NativeObject { public: static const JSClass class_; static const JSClass protoClass_; }; /* * Wrapper for iterators created via Iterator.from. * Iterator Helpers proposal 2.1.3.3.1.1. */ class WrapForValidIteratorObject : public NativeObject { public: static const JSClass class_; enum { IteratorSlot, NextMethodSlot, SlotCount }; static_assert( IteratorSlot == WRAP_FOR_VALID_ITERATOR_ITERATOR_SLOT, "IteratedSlot must match self-hosting define for iterator object slot."); static_assert( NextMethodSlot == WRAP_FOR_VALID_ITERATOR_NEXT_METHOD_SLOT, "NextMethodSlot must match self-hosting define for next method slot."); }; WrapForValidIteratorObject* NewWrapForValidIterator(JSContext* cx); /* * Generator-esque object returned by Iterator Helper methods. */ class IteratorHelperObject : public NativeObject { public: static const JSClass class_; enum { // The implementation (an instance of one of the generators in // builtin/Iterator.js). // Never null. GeneratorSlot, SlotCount, }; static_assert(GeneratorSlot == ITERATOR_HELPER_GENERATOR_SLOT, "GeneratorSlot must match self-hosting define for generator " "object slot."); }; IteratorHelperObject* NewIteratorHelper(JSContext* cx); bool IterableToArray(JSContext* cx, HandleValue iterable, MutableHandle array); // Typed arrays and classes with an enumerate hook can have extra properties not // included in the shape's property map or the object's dense elements. static inline bool ClassCanHaveExtraEnumeratedProperties(const JSClass* clasp) { return IsTypedArrayClass(clasp) || clasp->getNewEnumerate() || clasp->getEnumerate(); } } /* namespace js */ #endif /* vm_Iteration_h */