Merge up to 8597 to experimental/gc from the bleeding edge.

src/global-handles.h

 // Copyright 2011 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 144 matching lines @@
   // Tells whether global handle is weak.
   static bool IsWeak(Object** location);
 
   // Process pending weak handles.
   // Returns true if next major GC is likely to collect more garbage.
   bool PostGarbageCollectionProcessing(GarbageCollector collector);
 
   // Iterates over all strong handles.
   void IterateStrongRoots(ObjectVisitor* v);
 
-  // Iterates over all strong and dependent handles.
-  void IterateStrongAndDependentRoots(ObjectVisitor* v);
-
   // Iterates over all handles.
   void IterateAllRoots(ObjectVisitor* v);
 
   // Iterates over all handles that have embedder-assigned class ID.
   void IterateAllRootsWithClassIds(ObjectVisitor* v);
 
   // Iterates over all weak roots in heap.
   void IterateWeakRoots(ObjectVisitor* v);
 
-  // Iterates over all weak independent roots in heap.
-  void IterateWeakIndependentRoots(ObjectVisitor* v);
-
   // Iterates over weak roots that are bound to a given callback.
   void IterateWeakRoots(WeakReferenceGuest f,
                         WeakReferenceCallback callback);
 
   // Find all weak handles satisfying the callback predicate, mark
   // them as pending.
   void IdentifyWeakHandles(WeakSlotCallback f);
 
-  // Find all weak independent handles satisfying the callback predicate, mark
-  // them as pending.
-  void IdentifyWeakIndependentHandles(WeakSlotCallbackWithHeap f);
+  // NOTE: Three ...NewSpace... functions below are used during
+  // scavenge collections and iterate over sets of handles that are
+  // guaranteed to contain all handles holding new space objects (but
+  // may also include old space objects).
+
+  // Iterates over strong and dependent handles. See the node above.
+  void IterateNewSpaceStrongAndDependentRoots(ObjectVisitor* v);
+
+  // Finds weak independent handles satisfying the callback predicate
+  // and marks them as pending. See the note above.
+  void IdentifyNewSpaceWeakIndependentHandles(WeakSlotCallbackWithHeap f);
+
+  // Iterates over weak independent handles. See the note above.
+  void IterateNewSpaceWeakIndependentRoots(ObjectVisitor* v);
 
   // Add an object group.
   // Should be only used in GC callback function before a collection.
   // All groups are destroyed after a mark-compact collection.
   void AddObjectGroup(Object*** handles,
                       size_t length,
                       v8::RetainedObjectInfo* info);
 
   // Add an implicit references' group.
   // Should be only used in GC callback function before a collection.
@@ skipping 16 matching lines @@
 
   // Tear down the global handle structure.
   void TearDown();
 
   Isolate* isolate() { return isolate_; }
 
 #ifdef DEBUG
   void PrintStats();
   void Print();
 #endif
-  class Pool;
+
  private:
   explicit GlobalHandles(Isolate* isolate);
 
-  // Internal node structure, one for each global handle.
+  // Internal node structures.
   class Node;
+  class NodeBlock;
+  class NodeIterator;
 
   Isolate* isolate_;
 
   // Field always containing the number of weak and near-death handles.
   int number_of_weak_handles_;
 
   // Field always containing the number of weak and near-death handles
   // to global objects.  These objects are also included in
   // number_of_weak_handles_.
   int number_of_global_object_weak_handles_;
 
-  // Global handles are kept in a single linked list pointed to by head_.
-  Node* head_;
-  Node* head() { return head_; }
-  void set_head(Node* value) { head_ = value; }
+  // List of all allocated node blocks.
+  NodeBlock* first_block_;
 
-  // Free list for DESTROYED global handles not yet deallocated.
+  // List of node blocks with used nodes.
+  NodeBlock* first_used_block_;
+
+  // Free list of nodes.
   Node* first_free_;
-  Node* first_free() { return first_free_; }
-  void set_first_free(Node* value) { first_free_ = value; }
 
-  // List of deallocated nodes.
-  // Deallocated nodes form a prefix of all the nodes and
-  // |first_deallocated| points to last deallocated node before
-  // |head|.  Those deallocated nodes are additionally linked
-  // by |next_free|:
-  //                                    1st deallocated  head
-  //                                           |          |
-  //                                           V          V
-  //    node          node        ...         node       node
-  //      .next      -> .next ->                .next ->
-  //   <- .next_free <- .next_free           <- .next_free
-  Node* first_deallocated_;
-  Node* first_deallocated() { return first_deallocated_; }
-  void set_first_deallocated(Node* value) {
-    first_deallocated_ = value;
-  }
+  // Contains all nodes holding new space objects. Note: when the list
+  // is accessed, some of the objects may have been promoted already.
+  List<Node*> new_space_nodes_;
 
-  Pool* pool_;
   int post_gc_processing_count_;
+
   List<ObjectGroup*> object_groups_;
   List<ImplicitRefGroup*> implicit_ref_groups_;
 
   friend class Isolate;
 
   DISALLOW_COPY_AND_ASSIGN(GlobalHandles);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBAL_HANDLES_H_