WIP: Blocks for global handles.

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index 3477bcaaa9504d2fd370d6a253487ff32e9581ab..53ab461110e27383916c60e1e86c5f80f6df220d 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -224,12 +224,14 @@ class GlobalHandles {
   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_;
 
@@ -241,37 +243,15 @@ class GlobalHandles {
   // 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; }
-
-  // Free list for DESTROYED global handles not yet deallocated.
+  NodeBlock* first_block_;
+  NodeBlock* first_used_block_;
   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;
-  }
 
-  Pool* pool_;
   int post_gc_processing_count_;
+
   List<ObjectGroup*> object_groups_;
   List<ImplicitRefGroup*> implicit_ref_groups_;
+  List<Node*> new_space_independent_;
 
   friend class Isolate;