Add DMB instruction to the ARM integrated assembler.

src/IceAssemblerARM32.h

 //===- subzero/src/IceAssemblerARM32.h - Assembler for ARM32 ----*- C++ -*-===//
 //
 // 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.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
@@ skipping 191 matching lines @@
   void bl(const ConstantRelocatable *Target);
 
   void blx(const Operand *Target);
 
   void bx(RegARM32::GPRRegister Rm, CondARM32::Cond Cond = CondARM32::AL);
 
   void cmn(const Operand *OpRn, const Operand *OpSrc1, CondARM32::Cond Cond);
 
   void cmp(const Operand *OpRn, const Operand *OpSrc1, CondARM32::Cond Cond);
 
+  void dmb(IValueT Option); // Option is a 4-bit value.
+
   void eor(const Operand *OpRd, const Operand *OpRn, const Operand *OpSrc1,
            bool SetFlags, CondARM32::Cond Cond);
 
   void ldr(const Operand *OpRt, const Operand *OpAddress, CondARM32::Cond Cond,
            const TargetInfo &TInfo);
 
   void ldr(const Operand *OpRt, const Operand *OpAddress, CondARM32::Cond Cond,
            const TargetLowering *Lowering) {
     const TargetInfo TInfo(Lowering);
     ldr(OpRt, OpAddress, Cond, TInfo);
@@ skipping 196 matching lines @@
   // where cccc=Cond, xxxxxxx<<21=Opcode, dddd=Rd, s=SetFlags, and
   // iiiiiiiiiiiiiiii=Imm16.
   void emitMovwt(CondARM32::Cond Cond, bool IsMovw, const Operand *OpRd,
                  const Operand *OpSrc, const char *MovName);
 };
 
 } // end of namespace ARM32
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEASSEMBLERARM32_H