Introduce EmbedderReachableReferenceReporter

src/heap/heap.h

 // 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_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 319 matching lines @@
 class MemoryAllocator;
 class MemoryReducer;
 class ObjectIterator;
 class ObjectStats;
 class Page;
 class PagedSpace;
 class Scavenger;
 class ScavengeJob;
 class Space;
 class StoreBuffer;
+class TracePossibleWrapperReporter;
 class WeakObjectRetainer;
 
 typedef void (*ObjectSlotCallback)(HeapObject** from, HeapObject* to);
 
 enum PromotionMode { PROMOTE_MARKED, DEFAULT_PROMOTION };
 
 enum ArrayStorageAllocationMode {
   DONT_INITIALIZE_ARRAY_ELEMENTS,
   INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE
 };
@@ skipping 847 matching lines @@
   void RegisterReservationsForBlackAllocation(Reservation* reservations);
 
   IncrementalMarking* incremental_marking() { return incremental_marking_; }
 
   // ===========================================================================
   // Embedder heap tracer support. =============================================
   // ===========================================================================
 
   void SetEmbedderHeapTracer(EmbedderHeapTracer* tracer);
 
-  bool UsingEmbedderHeapTracer();
+  bool UsingEmbedderHeapTracer() { return embedder_heap_tracer() != nullptr; }
 
   void TracePossibleWrapper(JSObject* js_object);
 
   void RegisterExternallyReferencedObject(Object** object);
 
+  void RegisterWrappersWithEmbedderHeapTracer();
+
+  // In order to avoid running out of memory we force tracing wrappers if there
+  // are too many of them.
+  bool RequiresImmediateWrapperProcessing();
+
+  EmbedderHeapTracer* embedder_heap_tracer() { return embedder_heap_tracer_; }
+
+  EmbedderReachableReferenceReporter* embedder_reachable_reference_reporter() {
+    return embedder_reference_reporter_;
+  }
+
+  size_t wrappers_to_trace() { return wrappers_to_trace_.size(); }
+
   // ===========================================================================
   // External string table API. ================================================
   // ===========================================================================
 
   // Registers an external string.
   inline void RegisterExternalString(String* string);
 
   // Finalizes an external string by deleting the associated external
   // data and clearing the resource pointer.
   inline void FinalizeExternalString(String* string);
@@ skipping 1091 matching lines @@
 
   int gc_callbacks_depth_;
 
   bool deserialization_complete_;
 
   StrongRootsList* strong_roots_list_;
 
   // The depth of HeapIterator nestings.
   int heap_iterator_depth_;
 
+  EmbedderHeapTracer* embedder_heap_tracer_;
+  EmbedderReachableReferenceReporter* embedder_reference_reporter_;
+  std::vector<std::pair<void*, void*>> wrappers_to_trace_;
+
   // Used for testing purposes.
   bool force_oom_;
 
   // Classes in "heap" can be friends.
   friend class AlwaysAllocateScope;
   friend class GCCallbacksScope;
   friend class GCTracer;
   friend class HeapIterator;
   friend class IdleScavengeObserver;
   friend class IncrementalMarking;
@@ skipping 303 matching lines @@
   intptr_t step_size_;
   intptr_t bytes_to_next_step_;
 
  private:
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
+class TracePossibleWrapperReporter : public EmbedderReachableReferenceReporter {
+ public:
+  explicit TracePossibleWrapperReporter(Heap* heap) : heap_(heap) {}
+  void ReportExternalReference(Value* object) override {
+    heap_->RegisterExternallyReferencedObject(
+        reinterpret_cast<Object**>(object));
+  }
+
+ private:
+  Heap* heap_;
+};
+
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_