Rearrange emit vs emitIAS. Wait till function is done before dumping text.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index dcb83ed68b39b69485f63e2b27c6e17029875739..8d63d989e4694a21220ac3519c41755d9a389356 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -206,7 +206,7 @@ class Assembler {
   Assembler &operator=(const Assembler &) = delete;
 
 public:
-  Assembler() {}
+  Assembler() : buffer_(*this) {}
   virtual ~Assembler() {}
 
   // Allocate a chunk of bytes using the per-Assembler allocator.
@@ -226,8 +226,13 @@ public:
 
   virtual void BindCfgNodeLabel(SizeT NodeNumber) = 0;
 
+  void emitIASBytes(GlobalContext *Ctx) const;
+
 private:
   llvm::BumpPtrAllocator Allocator;
+
+protected:
+  AssemblerBuffer buffer_;
 };
 
 } // end of namespace Ice