Show references from weak containers as weak in heap snapshots.

src/heap-snapshot-generator.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * 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
@@ skipping 358 matching lines @@
   HeapEntry* AddEntry(Address address,
                       HeapEntry::Type type,
                       const char* name,
                       size_t size);
 
   static String* GetConstructorName(JSObject* object);
 
   static HeapObject* const kInternalRootObject;
 
  private:
+  typedef void (V8HeapExplorer::*ExtractReferencesMethod)(HeapObject* object);
+
   HeapEntry* AddEntry(HeapObject* object);
   HeapEntry* AddEntry(HeapObject* object,
                       HeapEntry::Type type,
                       const char* name);
 
   const char* GetSystemEntryName(HeapObject* object);
 
-  void ExtractReferences(HeapObject* obj);
+  template<V8HeapExplorer::ExtractReferencesMethod extractor>
+  bool IterateAndExtractSinglePass();
+
+  void ExtractReferencesPass1(HeapObject* obj);
+  void ExtractReferencesPass2(HeapObject* obj);
   void ExtractJSGlobalProxyReferences(int entry, JSGlobalProxy* proxy);
   void ExtractJSObjectReferences(int entry, JSObject* js_obj);
   void ExtractStringReferences(int entry, String* obj);
   void ExtractContextReferences(int entry, Context* context);
   void ExtractMapReferences(int entry, Map* map);
   void ExtractSharedFunctionInfoReferences(int entry,
                                            SharedFunctionInfo* shared);
   void ExtractScriptReferences(int entry, Script* script);
   void ExtractAccessorPairReferences(int entry, AccessorPair* accessors);
   void ExtractCodeCacheReferences(int entry, CodeCache* code_cache);
   void ExtractCodeReferences(int entry, Code* code);
   void ExtractBoxReferences(int entry, Box* box);
   void ExtractCellReferences(int entry, Cell* cell);
   void ExtractPropertyCellReferences(int entry, PropertyCell* cell);
   void ExtractAllocationSiteReferences(int entry, AllocationSite* site);
   void ExtractJSArrayBufferReferences(int entry, JSArrayBuffer* buffer);
+  void ExtractFixedArrayReferences(int entry, FixedArray* array);
   void ExtractClosureReferences(JSObject* js_obj, int entry);
   void ExtractPropertyReferences(JSObject* js_obj, int entry);
   bool ExtractAccessorPairProperty(JSObject* js_obj, int entry,
                                    Object* key, Object* callback_obj);
   void ExtractElementReferences(JSObject* js_obj, int entry);
   void ExtractInternalReferences(JSObject* js_obj, int entry);
+
   bool IsEssentialObject(Object* object);
   void SetContextReference(HeapObject* parent_obj,
                            int parent,
                            String* reference_name,
                            Object* child,
                            int field_offset);
   void SetNativeBindReference(HeapObject* parent_obj,
                               int parent,
                               const char* reference_name,
                               Object* child);
@@ skipping 13 matching lines @@
                             int field_offset = -1);
   void SetHiddenReference(HeapObject* parent_obj,
                           int parent,
                           int index,
                           Object* child);
   void SetWeakReference(HeapObject* parent_obj,
                         int parent,
                         const char* reference_name,
                         Object* child_obj,
                         int field_offset);
+  void SetWeakReference(HeapObject* parent_obj,
+                        int parent,
+                        int index,
+                        Object* child_obj,
+                        int field_offset);
   void SetPropertyReference(HeapObject* parent_obj,
                             int parent,
                             Name* reference_name,
                             Object* child,
                             const char* name_format_string = NULL,
                             int field_offset = -1);
   void SetUserGlobalReference(Object* user_global);
   void SetRootGcRootsReference();
   void SetGcRootsReference(VisitorSynchronization::SyncTag tag);
   void SetGcSubrootReference(
       VisitorSynchronization::SyncTag tag, bool is_weak, Object* child);
   const char* GetStrongGcSubrootName(Object* object);
   void TagObject(Object* obj, const char* tag);
+  void MarkAsWeakContainer(Object* object);
 
   HeapEntry* GetEntry(Object* obj);
 
   static inline HeapObject* GetNthGcSubrootObject(int delta);
   static inline int GetGcSubrootOrder(HeapObject* subroot);
 
   Heap* heap_;
   HeapSnapshot* snapshot_;
   StringsStorage* names_;
   HeapObjectsMap* heap_object_map_;
   SnapshottingProgressReportingInterface* progress_;
   SnapshotFiller* filler_;
   HeapObjectsSet objects_tags_;
   HeapObjectsSet strong_gc_subroot_names_;
   HeapObjectsSet user_roots_;
+  HeapObjectsSet weak_containers_;
   v8::HeapProfiler::ObjectNameResolver* global_object_name_resolver_;
 
   static HeapObject* const kGcRootsObject;
   static HeapObject* const kFirstGcSubrootObject;
   static HeapObject* const kLastGcSubrootObject;
 
   friend class IndexedReferencesExtractor;
   friend class GcSubrootsEnumerator;
   friend class RootsReferencesExtractor;
 
@@ skipping 142 matching lines @@
   friend class HeapSnapshotJSONSerializerEnumerator;
   friend class HeapSnapshotJSONSerializerIterator;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshotJSONSerializer);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_SNAPSHOT_GENERATOR_H_