Revert 428. Breaks 64-bit compilation.

src/debug.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 215 matching lines @@
     k_debug_break_return_address,
     k_register_address
   };
 
   // Support for setting the address to jump to when returning from break point.
   static Address* after_break_target_address() {
     return reinterpret_cast<Address*>(&thread_local_.after_break_target_);
   }
 
   // Support for saving/restoring registers when handling debug break calls.
-  static Object** register_address(int r) {
-    return &registers_[r];
+  static Address* register_address(int r) {
+    return reinterpret_cast<Address *>(&registers_[r]);
   }
 
   // Address of the debug break return entry code.
   static Code* debug_break_return_entry() { return debug_break_return_entry_; }
 
   // Support for getting the address of the debug break on return code.
-  static Code** debug_break_return_address() {
-    return &debug_break_return_;
+  static Address* debug_break_return_address() {
+    return reinterpret_cast<Address*>(&debug_break_return_);
   }
 
   static const int kEstimatedNofDebugInfoEntries = 16;
   static const int kEstimatedNofBreakPointsInFunction = 16;
 
   static void HandleWeakDebugInfo(v8::Persistent<v8::Object> obj, void* data);
 
   friend class Debugger;
   friend Handle<FixedArray> GetDebuggedFunctions();  // Found in test-debug.cc
 
@@ skipping 318 matching lines @@
   }
  private:
   Debug::AddressId id_;
   int reg_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8_DEBUG_H_