Make object groups and implicit references a bit more lightweight.

src/allocation.h

 // Copyright 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 33 matching lines @@
  public:
   void* operator new(size_t size) { return New(size); }
   void  operator delete(void* p) { Delete(p); }
 
   static void FatalProcessOutOfMemory();
   static void* New(size_t size);
   static void Delete(void* p);
 };
 
 
+// Superclass for classes with custom allocation.
+class CustomlyAllocated {

[antonm, 2011/04/06 11:01:48]

I don't like the name, but I cannot come up with anything better.

However, apparently the best way to make class really custom allocated is by
making its ctor/dtor private (so it cannot be stack allocated).

Maybe just declare a macro for it and forget about special base class?

[Vitaly Repeshko, 2011/04/06 19:11:01]

Yeah, since it requires hiding both new/delete and ctor/dtor, we need a macro.
But given that we'd only have two usages, I removed this base class and made
new/delete private explicitly in the global handle classes.

+ private:
+  void* operator new(size_t size);
+  void operator delete(void* p);
+};
+
+
 // A macro is used for defining the base class used for embedded instances.
 // The reason is some compilers allocate a minimum of one word for the
 // superclass. The macro prevents the use of new & delete in debug mode.
 // In release mode we are not willing to pay this overhead.
 
 #ifdef DEBUG
 // Superclass for classes with instances allocated inside stack
 // activations or inside other objects.
 class Embedded {
  public:
@@ skipping 70 matching lines @@
 
   friend class Isolate;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PreallocatedStorage);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ALLOCATION_H_