Improve mark-compact object grouping interface.

src/global-handles.h

 // Copyright 2007-2008 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 23 matching lines @@
 
 // Structure for tracking global handles.
 // A single list keeps all the allocated global handles.
 // Destroyed handles stay in the list but is added to the free list.
 // At GC the destroyed global handles are removed from the free list
 // and deallocated.
 
 // Callback function on handling weak global handles.
 // typedef bool (*WeakSlotCallback)(Object** pointer);
 
-// An object group is indexed by an id. An object group is treated like
-// a single JS object: if one of object in the group is alive,
-// all objects in the same group are considered alive.
+// An object group is treated like a single JS object: if one of object in
+// the group is alive, all objects in the same group are considered alive.
 // An object group is used to simulate object relationship in a DOM tree.
 class ObjectGroup : public Malloced {
  public:
-  explicit ObjectGroup(void* id) : id_(id), objects_(4) {}
+  ObjectGroup() : objects_(4) {}
+  explicit ObjectGroup(size_t capacity) : objects_(capacity) {}
 
-  void* id_;
   List<Object**> objects_;
 };
 
 
 class GlobalHandles : public AllStatic {
  public:
   // Creates a new global handle that is alive until Destroy is called.
   static Handle<Object> Create(Object* value);
 
   // Destroy a global handle.
@@ skipping 32 matching lines @@
 
   // Iterates over all handles.
   static void IterateRoots(ObjectVisitor* v);
 
   // Iterates over all weak roots in heap.
   static void IterateWeakRoots(ObjectVisitor* v);
 
   // Mark the weak pointers based on the callback.
   static void MarkWeakRoots(WeakSlotCallback f);
 
-  // Add an object to a group indexed by an id.
+  // Add an object group.
   // Should only used in GC callback function before a collection.
   // All groups are destroyed after a mark-compact collection.
-  static void AddToGroup(void* id, Object** location);
+  static void AddGroup(Object*** handles, size_t length);
 
   // Returns the object groups.
-  static List<ObjectGroup*>& ObjectGroups() {
-    return object_groups_;
-  }
+  static List<ObjectGroup*>* ObjectGroups();
 
   // Remove bags, this should only happen after GC.
   static void RemoveObjectGroups();
 
   // Tear down the global handle structure.
   static void TearDown();
 
 #ifdef DEBUG
   static void PrintStats();
   static void Print();
@@ skipping 12 matching lines @@
 
   // Global handles are kept in a single linked list pointed to by head_.
   static Node* head_;
   static Node* head() { return head_; }
   static void set_head(Node* value) { head_ = value; }
 
   // Free list for DESTROYED global handles not yet deallocated.
   static Node* first_free_;
   static Node* first_free() { return first_free_; }
   static void set_first_free(Node* value) { first_free_ = value; }
-
-  // A list of object groups.
-  static List<ObjectGroup*> object_groups_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBAL_HANDLES_H_