New GC related APIs: Implicit references.

include/v8.h

 // Copyright 2012 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 3525 matching lines @@
                              RetainedObjectInfo* info = NULL);
 
   static void SetObjectGroupId(Isolate* isolate,
                                const Persistent<Value>& object,
                                UniqueId id);
 
   static void SetRetainedObjectInfo(Isolate* isolate,
                                     UniqueId id,
                                     RetainedObjectInfo* info);
 
+  static void SetObjectGroupRepresentativeObject(

[Michael Starzinger, 2013/04/16 10:42:16]

Can we add a short comment to this method that mentions this is used in
conjunction with implicit references? Also how about naming this just
"SetObjectGroupRepresentative()", I'll leave that up to you and Sven?

[marja, 2013/04/16 12:28:37]

Done.

+      Isolate* isolate,
+      UniqueId id,
+      const Persistent<Object>& object);
+
   /**
    * Allows the host application to declare implicit references between
    * the objects: if |parent| is alive, all |children| are alive too.
    * After each garbage collection, all implicit references
    * are removed.  It is intended to be used in the before-garbage-collection
    * callback function.
    */
+  // TODO(marja): Deprecate AddImplicitReferences. Use
+  // SetObjectGroupRepresentativeObject and AddImplicitReference instead.
   static void AddImplicitReferences(Persistent<Object> parent,
                                     Persistent<Value>* children,
                                     size_t length);
 
   /**
+   * Allows the host application to declare implicit references. If the
+   * representative object of the object group (identified by id) is alive, the
+   * children are alive too. After each garbage collection, all implicit
+   * references are removed. It is intended to be used in the
+   * before-garbage-collection callback function. */

[Michael Starzinger, 2013/04/16 10:42:16]

nit: Close comment on next line.

[marja, 2013/04/16 12:28:37]

Done.

+  static void AddImplicitReference(Isolate* isolate,
+                                   UniqueId id,
+                                   const Persistent<Value>& object);
+
+  /**
    * Initializes from snapshot if possible. Otherwise, attempts to
    * initialize from scratch.  This function is called implicitly if
    * you use the API without calling it first.
    */
   static bool Initialize();
 
   /**
    * Allows the host application to provide a callback which can be used
    * as a source of entropy for random number generators.
    */
@@ skipping 1590 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_