Allow collection of DOM objects in minor GC cycles.

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 384 matching lines @@
 
   /**
    * Marks the reference to this object independent. Garbage collector
    * is free to ignore any object groups containing this object.
    * Weak callback for an independent handle should not
    * assume that it will be preceded by a global GC prologue callback
    * or followed by a global GC epilogue callback.
    */
   inline void MarkIndependent();
 
+  /**
+   * Marks the reference to this object partially dependent. Partially
+   * dependent handles only depend on other partially dependent handles and
+   * these dependencies are provided through object groups. It provides a way
+   * to build smaller object groups for young objects that represent only a
+   * subset of all external dependencies. This mark is automatically cleared
+   * after each garbage collection.
+   */
+  inline void MarkPartiallyDependent();
+
   /** Returns true if this handle was previously marked as independent. */
   inline bool IsIndependent() const;
 
   /** Checks if the handle holds the only reference to an object. */
   inline bool IsNearDeath() const;
 
   /** Returns true if the handle's reference is weak.  */
   inline bool IsWeak() const;
 
   /**
@@ skipping 2832 matching lines @@
    * Removes callback that was installed by AddCallCompletedCallback.
    */
   static void RemoveCallCompletedCallback(CallCompletedCallback callback);
 
   /**
    * Allows the host application to group objects together. If one
    * object in the group is alive, all objects in the group are alive.
    * After each garbage collection, object groups are removed. It is
    * intended to be used in the before-garbage-collection callback
    * function, for instance to simulate DOM tree connections among JS
-   * wrapper objects.
+   * wrapper objects. Object groups for all dependent handles need to
+   * be provided for kGCTypeMarkSweepCompact collections, for all other
+   * garbage collection types it is sufficient to provide object groups
+   * for partially dependent handles only.
    * See v8-profiler.h for RetainedObjectInfo interface description.
    */
   static void AddObjectGroup(Persistent<Value>* objects,
                              size_t length,
                              RetainedObjectInfo* info = NULL);
 
   /**
    * 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
@@ skipping 218 matching lines @@
  private:
   V8();
 
   static internal::Object** GlobalizeReference(internal::Object** handle);
   static void DisposeGlobal(internal::Object** global_handle);
   static void MakeWeak(internal::Object** global_handle,
                        void* data,
                        WeakReferenceCallback);
   static void ClearWeak(internal::Object** global_handle);
   static void MarkIndependent(internal::Object** global_handle);
+  static void MarkPartiallyDependent(internal::Object** global_handle);
   static bool IsGlobalIndependent(internal::Object** global_handle);
   static bool IsGlobalNearDeath(internal::Object** global_handle);
   static bool IsGlobalWeak(internal::Object** global_handle);
   static void SetWrapperClassId(internal::Object** global_handle,
                                 uint16_t class_id);
   static uint16_t GetWrapperClassId(internal::Object** global_handle);
 
   template <class T> friend class Handle;
   template <class T> friend class Local;
   template <class T> friend class Persistent;
@@ skipping 751 matching lines @@
 void Persistent<T>::ClearWeak() {
   V8::ClearWeak(reinterpret_cast<internal::Object**>(**this));
 }
 
 template <class T>
 void Persistent<T>::MarkIndependent() {
   V8::MarkIndependent(reinterpret_cast<internal::Object**>(**this));
 }
 
 template <class T>
+void Persistent<T>::MarkPartiallyDependent() {
+  V8::MarkPartiallyDependent(reinterpret_cast<internal::Object**>(**this));
+}
+
+template <class T>
 void Persistent<T>::SetWrapperClassId(uint16_t class_id) {
   V8::SetWrapperClassId(reinterpret_cast<internal::Object**>(**this), class_id);
 }
 
 template <class T>
 uint16_t Persistent<T>::WrapperClassId() const {
   return V8::GetWrapperClassId(reinterpret_cast<internal::Object**>(**this));
 }
 
 Arguments::Arguments(internal::Object** implicit_args,
@@ skipping 419 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_