Add hybrid assembler concept to ARM assembler.

src/IceGlobalContext.h

 //===- subzero/src/IceGlobalContext.h - Global context defs -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 157 matching lines @@
   /// arbitrary amount of work during which far-away callees may grab
   /// the stream and do something with it, and finally the thread
   /// releases the stream lock.  This allows large chunks of output to
   /// be dumped or emitted without risking interleaving from multiple
   /// threads.
   void lockStr() { StrLock.lock(); }
   void unlockStr() { StrLock.unlock(); }
   Ostream &getStrDump() { return *StrDump; }
   Ostream &getStrError() { return *StrError; }
   Ostream &getStrEmit() { return *StrEmit; }
+  void setStrEmit(Ostream &NewStrEmit) { StrEmit = &NewStrEmit; }
 
   LockedPtr<ErrorCode> getErrorStatus() {
     return LockedPtr<ErrorCode>(&ErrorStatus, &ErrorStatusLock);
   }
 
   /// When emitting assembly, we allow a string to be prepended to
   /// names of translated functions.  This makes it easier to create an
   /// execution test against a reference translator like llc, with both
   /// translators using the same bitcode as input.
   IceString mangleName(const IceString &Name) const;
@@ skipping 412 matching lines @@
   explicit OstreamLocker(GlobalContext *Ctx) : Ctx(Ctx) { Ctx->lockStr(); }
   ~OstreamLocker() { Ctx->unlockStr(); }
 
 private:
   GlobalContext *const Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEGLOBALCONTEXT_H