// Copyright 2012 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef V8_HEAP_OBJECTS_VISITING_H_ #define V8_HEAP_OBJECTS_VISITING_H_ #include "src/objects/fixed-array.h" #include "src/objects/map.h" #include "src/objects/objects.h" #include "src/objects/visitors.h" #include "torque-generated/field-offsets.h" namespace v8 { namespace internal { #define TYPED_VISITOR_ID_LIST(V) \ V(AllocationSite) \ V(BigInt) \ V(ByteArray) \ V(BytecodeArray) \ V(Cell) \ V(Code) \ V(CodeDataContainer) \ V(CoverageInfo) \ V(DataHandler) \ V(EmbedderDataArray) \ V(EphemeronHashTable) \ V(FeedbackCell) \ V(FeedbackMetadata) \ V(FixedDoubleArray) \ V(JSArrayBuffer) \ V(JSDataView) \ V(JSFunction) \ V(JSObject) \ V(JSTypedArray) \ V(WeakCell) \ V(JSWeakCollection) \ V(JSWeakRef) \ V(Map) \ V(NativeContext) \ V(PreparseData) \ V(PropertyArray) \ V(PropertyCell) \ V(PrototypeInfo) \ V(SmallOrderedHashMap) \ V(SmallOrderedHashSet) \ V(SmallOrderedNameDictionary) \ V(SourceTextModule) \ V(Symbol) \ V(SyntheticModule) \ V(TransitionArray) \ V(WasmArray) \ V(WasmIndirectFunctionTable) \ V(WasmInstanceObject) \ V(WasmStruct) \ V(WasmTypeInfo) #define FORWARD_DECLARE(TypeName) class TypeName; TYPED_VISITOR_ID_LIST(FORWARD_DECLARE) TORQUE_VISITOR_ID_LIST(FORWARD_DECLARE) #undef FORWARD_DECLARE // The base class for visitors that need to dispatch on object type. The default // behavior of all visit functions is to iterate body of the given object using // the BodyDescriptor of the object. // // The visit functions return the size of the object cast to ResultType. // // This class is intended to be used in the following way: // // class SomeVisitor : public HeapVisitor<ResultType, SomeVisitor> { // ... // } template <typename ResultType, typename ConcreteVisitor> class HeapVisitor : public ObjectVisitor { public: V8_INLINE ResultType Visit(HeapObject object); V8_INLINE ResultType Visit(Map map, HeapObject object); protected: // A guard predicate for visiting the object. // If it returns false then the default implementations of the Visit* // functions bailout from iterating the object pointers. V8_INLINE bool ShouldVisit(HeapObject object) { return true; } // Guard predicate for visiting the objects map pointer separately. V8_INLINE bool ShouldVisitMapPointer() { return true; } // A callback for visiting the map pointer in the object header. V8_INLINE void VisitMapPointer(HeapObject host); // If this predicate returns false, then the heap visitor will fail // in default Visit implemention for subclasses of JSObject. V8_INLINE bool AllowDefaultJSObjectVisit() { return true; } #define VISIT(TypeName) \ V8_INLINE ResultType Visit##TypeName(Map map, TypeName object); TYPED_VISITOR_ID_LIST(VISIT) TORQUE_VISITOR_ID_LIST(VISIT) #undef VISIT V8_INLINE ResultType VisitShortcutCandidate(Map map, ConsString object); V8_INLINE ResultType VisitDataObject(Map map, HeapObject object); V8_INLINE ResultType VisitJSObjectFast(Map map, JSObject object); V8_INLINE ResultType VisitJSApiObject(Map map, JSObject object); V8_INLINE ResultType VisitStruct(Map map, HeapObject object); V8_INLINE ResultType VisitFreeSpace(Map map, FreeSpace object); template <typename T> static V8_INLINE T Cast(HeapObject object); }; template <typename ConcreteVisitor> class NewSpaceVisitor : public HeapVisitor<int, ConcreteVisitor> { public: V8_INLINE bool ShouldVisitMapPointer() { return false; } // Special cases for young generation. V8_INLINE int VisitNativeContext(Map map, NativeContext object); V8_INLINE int VisitJSApiObject(Map map, JSObject object); int VisitBytecodeArray(Map map, BytecodeArray object) { UNREACHABLE(); return 0; } int VisitSharedFunctionInfo(Map map, SharedFunctionInfo object); int VisitWeakCell(Map map, WeakCell weak_cell); }; class WeakObjectRetainer; // A weak list is single linked list where each element has a weak pointer to // the next element. Given the head of the list, this function removes dead // elements from the list and if requested records slots for next-element // pointers. The template parameter T is a WeakListVisitor that defines how to // access the next-element pointers. template <class T> Object VisitWeakList(Heap* heap, Object list, WeakObjectRetainer* retainer); } // namespace internal } // namespace v8 #endif // V8_HEAP_OBJECTS_VISITING_H_