Skeleton of a linear scan register allocator.

runtime/vm/flow_graph_compiler_x64.h

Index: runtime/vm/flow_graph_compiler_x64.h
diff --git a/runtime/vm/flow_graph_compiler_x64.h b/runtime/vm/flow_graph_compiler_x64.h
index c7fe8c332c610aa4aac72c982b8fa263fce18787..c1fa60a4413fea64ac2122939970c7e772b78eb1 100644
--- a/runtime/vm/flow_graph_compiler_x64.h
+++ b/runtime/vm/flow_graph_compiler_x64.h
@@ -29,6 +29,7 @@ class FlowGraphCompiler : public ValueObject {
                     const ParsedFunction& parsed_function,
                     const GrowableArray<BlockEntryInstr*>& block_order,
                     bool is_optimizing,
+                    bool is_ssa,
                     bool is_leaf);
 
   ~FlowGraphCompiler();
@@ -282,6 +283,7 @@ class FlowGraphCompiler : public ValueObject {
   GrowableArray<BlockInfo*> block_info_;
   GrowableArray<DeoptimizationStub*> deopt_stubs_;
   const bool is_optimizing_;
+  const bool is_ssa_;
   const bool is_dart_leaf_;
 
   const Bool& bool_true_;
@@ -289,6 +291,13 @@ class FlowGraphCompiler : public ValueObject {
   const Class& double_class_;
 
   FrameRegisterAllocator frame_register_allocator_;
+  ParallelMoveResolver parallel_move_resolver_;
+
+  // Currently instructions generate deopt stubs internally by
+  // calling AddDeoptStub.  To communicate deoptimization environment
+  // that should be used when deoptimizing we store it in this variable.
+  // In future AddDeoptStub should be moved out of the instruction template.
+  Environment* pending_deoptimization_env_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
@@ -305,6 +314,7 @@ class DeoptimizationStub : public ZoneAllocated {
         try_index_(try_index),
         reason_(reason),
         registers_(2),
+        deoptimization_env_(NULL),
         entry_label_() {}
 
   void Push(Register reg) { registers_.Add(reg); }
@@ -313,12 +323,17 @@ class DeoptimizationStub : public ZoneAllocated {
   // Implementation is in architecture specific file.
   void GenerateCode(FlowGraphCompiler* compiler);
 
+  void set_deoptimization_env(Environment* env) {
+    deoptimization_env_ = env;
+  }
+
  private:
   const intptr_t deopt_id_;
   const intptr_t deopt_token_pos_;
   const intptr_t try_index_;
   const DeoptReasonId reason_;
   GrowableArray<Register> registers_;
+  const Environment* deoptimization_env_;
   Label entry_label_;
 
   DISALLOW_COPY_AND_ASSIGN(DeoptimizationStub);