More code generation for the optimizing compiler.

- Add HReturn instruction
- Generate code for locals/if/return
- Setup infrastructure for register allocation. Currently
  emulate a stack.

Change-Id: Ib28c2dba80f6c526177ed9a7b09c0689ac8122fb
diff --git a/compiler/optimizing/builder.h b/compiler/optimizing/builder.h
index 399dd63..fff83a1 100644
--- a/compiler/optimizing/builder.h
+++ b/compiler/optimizing/builder.h
@@ -41,7 +41,8 @@
         exit_block_(nullptr),
         current_block_(nullptr),
         graph_(nullptr),
-        constant0_(nullptr) { }
+        constant0_(nullptr),
+        constant1_(nullptr) { }
 
   HGraph* BuildGraph(const DexFile::CodeItem& code);
 
@@ -58,6 +59,7 @@
   HBasicBlock* FindBlockStartingAt(int32_t index) const;
 
   HIntConstant* GetConstant0();
+  HIntConstant* GetConstant1();
   HIntConstant* GetConstant(int constant);
   void InitializeLocals(int count);
   HLocal* GetLocalAt(int register_index) const;
@@ -79,6 +81,7 @@
   HGraph* graph_;
 
   HIntConstant* constant0_;
+  HIntConstant* constant1_;
 
   DISALLOW_COPY_AND_ASSIGN(HGraphBuilder);
 };