Use shorter write-barrier filtering sequence when value is known to be non-smi.

runtime/vm/assembler.h

 // Copyright (c) 2012, 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_ASSEMBLER_H_
 #define VM_ASSEMBLER_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/globals.h"
@@ skipping 178 matching lines @@
   // description of kMinimumGap for the reasoning behind the value.
   static uword ComputeLimit(uword data, intptr_t capacity) {
     return data + capacity - kMinimumGap;
   }
 
   void ExtendCapacity();
 
   friend class AssemblerFixup;
 };
 
+
+enum ValueSminess {

[Ivan Posva, 2013/03/22 04:11:35]

You need to get a better name for this enum or just use a boolean.
Why do I think it is OK to use a boolean instead in this case: The value is not
set as a constant anywhere, it is always set using the result of a function
which has a Yes/No meaning.

[Vyacheslav Egorov (Google), 2013/03/22 11:22:50]

Killed enum, using boolean instead.

+  kValueCanBeSmi,
+  kValueIsNotSmi
+};
+
 }  // namespace dart
 
 
 #if defined(TARGET_ARCH_IA32)
 #include "vm/assembler_ia32.h"
 #elif defined(TARGET_ARCH_X64)
 #include "vm/assembler_x64.h"
 #elif defined(TARGET_ARCH_ARM)
 #include "vm/assembler_arm.h"
 #elif defined(TARGET_ARCH_MIPS)
 #include "vm/assembler_mips.h"
 #else
 #error Unknown architecture.
 #endif
 
 #endif  // VM_ASSEMBLER_H_