- Allow the use of branch delay slots.

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 72 matching lines @@
   template<typename T> T Load(int position) {
     ASSERT(position >= 0 && position <= (Size() - static_cast<int>(sizeof(T))));
     return *reinterpret_cast<T*>(contents_ + position);
   }
 
   template<typename T> void Store(int position, T value) {
     ASSERT(position >= 0 && position <= (Size() - static_cast<int>(sizeof(T))));
     *reinterpret_cast<T*>(contents_ + position) = value;
   }
 
+  template<typename T> void Backup() {

[Ivan Posva, 2013/03/07 16:57:41]

If you have a better suggestions for this name, such as UnEmit, I would like to
hear about them.

[zra, 2013/03/07 17:11:34]

Remit?

+    ASSERT(Size() >= static_cast<intptr_t>(sizeof(T)));
+    cursor_ -= sizeof(T);
+  }
+
   const ZoneGrowableArray<int>& pointer_offsets() const {
 #if defined(DEBUG)
     ASSERT(fixups_processed_);
 #endif
     return *pointer_offsets_;
   }
 
   // Emit an object pointer directly in the code.
   void EmitObject(const Object& object);
 
@@ skipping 97 matching lines @@
 #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_