Fix an undetected Smi overflow on ARM.

runtime/vm/assembler_ia32.h

 // Copyright (c) 2013, 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_IA32_H_
 #define VM_ASSEMBLER_IA32_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_ia32.h directly; use assembler.h instead.
 #endif
@@ skipping 609 matching lines @@
    * Macros for High-level operations and implemented on all architectures.
    */
 
   void CompareRegisters(Register a, Register b);
 
   // Issues a move instruction if 'to' is not the same as 'from'.
   void MoveRegister(Register to, Register from);
   void PopRegister(Register r);
 
   void AddImmediate(Register reg, const Immediate& imm);
+  void SubImmediate(Register reg, const Immediate& imm);
 
   void Drop(intptr_t stack_elements);
 
   void LoadObject(Register dst, const Object& object);
 
   // If 'object' is a large Smi, xor it with a per-assembler cookie value to
   // prevent user-controlled immediates from appearing in the code stream.
   void LoadObjectSafely(Register dst, const Object& object);
 
   void PushObject(const Object& object);
@@ skipping 252 matching lines @@
 }
 
 
 inline void Assembler::EmitOperandSizeOverride() {
   EmitUint8(0x66);
 }
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_IA32_H_