Add various forms of LDREX/STREX to ARM integrated assembler.

src/IceInstARM32.h

 //===- subzero/src/IceInstARM32.h - ARM32 machine instructions --*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 1148 matching lines @@
 
 public:
   /// Value must be a register.
   static InstARM32Strex *create(Cfg *Func, Variable *Dest, Variable *Value,
                                 OperandARM32Mem *Mem,
                                 CondARM32::Cond Predicate) {
     return new (Func->allocate<InstARM32Strex>())
         InstARM32Strex(Func, Dest, Value, Mem, Predicate);
   }
   void emit(const Cfg *Func) const override;
+  void emitIAS(const Cfg *Func) const override;
   void dump(const Cfg *Func) const override;
   static bool classof(const Inst *Inst) { return isClassof(Inst, Strex); }
 
 private:
   InstARM32Strex(Cfg *Func, Variable *Dest, Variable *Value,
                  OperandARM32Mem *Mem, CondARM32::Cond Predicate);
 };
 
 class InstARM32Trap : public InstARM32 {
   InstARM32Trap() = delete;
@@ skipping 193 matching lines @@
 // default implementations. Without this, there is the possibility of ODR
 // violations and link errors.
 
 template <> void InstARM32Ldr::emit(const Cfg *Func) const;
 template <> void InstARM32Movw::emit(const Cfg *Func) const;
 template <> void InstARM32Movt::emit(const Cfg *Func) const;
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINSTARM32_H