Avoid handle dereference during graph optimization.

src/handles.h

Index: src/handles.h
diff --git a/src/handles.h b/src/handles.h
index 684f4ca38e758110b73eb07eabc0b497613bb024..5bd36e72becac7ca5cf4ed650a3b0047d3dcdfb4 100644
--- a/src/handles.h
+++ b/src/handles.h
@@ -65,7 +65,7 @@ class Handle {
 
   // Check if this handle refers to the exact same object as the other handle.
   bool is_identical_to(const Handle<T> other) const {
-    return operator*() == *other;
+    return *location_ == *other.location();

[Jakob Kummerow, 2013/01/23 12:09:18]

Why "location_" vs "location()"? Let's be consistent.

[Yang, 2013/01/23 13:34:25]

Done.

   }
 
   // Provides the C++ dereference operator.
@@ -339,6 +339,36 @@ class NoHandleAllocation BASE_EMBEDDED {
 #endif
 };
 
+
+class NoHandleDereference BASE_EMBEDDED {
+ public:
+#ifndef DEBUG
+  NoHandleDereference() {}
+  ~NoHandleDereference() {}
+#else
+  inline NoHandleDereference();
+  inline ~NoHandleDereference();
+ private:
+  int old_state_;

[Jakob Kummerow, 2013/01/23 12:09:18]

This is used to store bools, so it should be a bool.

[Yang, 2013/01/23 13:34:25]

Done.

+  bool active_;
+#endif
+};
+
+
+class AllowHandleDereference BASE_EMBEDDED {
+ public:
+#ifndef DEBUG
+  AllowHandleDereference() {}
+  ~AllowHandleDereference() {}
+#else
+  inline AllowHandleDereference();
+  inline ~AllowHandleDereference();
+ private:
+  int old_state_;

[Jakob Kummerow, 2013/01/23 12:09:18]

Same here.

[Yang, 2013/01/23 13:34:25]

Done.

+  bool active_;
+#endif
+};
+
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_