Reduce the memory used by frame elements from two words to one by...

src/zone.h

 // Copyright 2006-2008 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 162 matching lines @@
 
 // ZoneScopes keep track of the current parsing and compilation
 // nesting and cleans up generated ASTs in the Zone when exiting the
 // outer-most scope.
 class ZoneScope BASE_EMBEDDED {
  public:
   explicit ZoneScope(ZoneScopeMode mode) : mode_(mode) {
     nesting_++;
   }
 
-  ~ZoneScope() {
-    if (--nesting_ == 0 && mode_ == DELETE_ON_EXIT) Zone::DeleteAll();
+  virtual ~ZoneScope() {
+    if (ShouldDeleteOnExit()) Zone::DeleteAll();
+    --nesting_;
+  }
+
+  bool ShouldDeleteOnExit() {
+    return nesting_ == 1 && mode_ == DELETE_ON_EXIT;
   }
 
   // For ZoneScopes that do not delete on exit by default, call this
   // method to request deletion on exit.
   void DeleteOnExit() {
     mode_ = DELETE_ON_EXIT;
   }
 
   static int nesting() { return nesting_; }
 
  private:
   ZoneScopeMode mode_;
   static int nesting_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ZONE_H_