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

vm/handles.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_HANDLES_H_
 #define VM_HANDLES_H_
 
 #include "vm/allocation.h"
 
 namespace dart {
@@ skipping 286 matching lines @@
 // }
 #if defined(DEBUG)
 class NoHandleScope : public StackResource {
  public:
   explicit NoHandleScope(BaseIsolate* isolate);
   ~NoHandleScope();
 
  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
 
 #endif  // VM_HANDLES_H_