Add fast paths for Smi values in the dart embedding api.

vm/handles.h

Index: vm/handles.h
===================================================================
--- vm/handles.h	(revision 6440)
+++ vm/handles.h	(working copy)
@@ -304,20 +304,13 @@
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(NoHandleScope);
 };
-#else  // defined(DEBUG)
-class NoHandleScope : public ValueObject {
- public:
-  explicit NoHandleScope(BaseIsolate* isolate) { }
-  ~NoHandleScope() { }
 
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(NoHandleScope);
-};
-#endif  // defined(DEBUG)
-
 // Macro to start a no handles scope in the code.
 #define NOHANDLESCOPE(isolate)                                                \
     dart::NoHandleScope no_vm_internal_handles_scope_(isolate);
+#else  // defined(DEBUG)
+#define NOHANDLESCOPE(isolate)
+#endif  // defined(DEBUG)

[siva, 2012/04/12 02:18:13]

Does this make a big difference in the numbers?

Sometimes it feels more readable not having a macro but
instead declaring an object:
{
  NoHandleScope no_handles;

  ...
  ...
}

Not a big deal, but if the performance difference is not significant than having
that option would be good.

[turnidge, 2012/04/16 20:07:24]

I had seen a difference before but was unable to reproduce it when I tried to
today.  I have reverted the change to handles.h, etc.

On 2012/04/12 02:18:13, asiva wrote:

 
 }  // namespace dart