Add functions for setting an environment and rebinding a use.

runtime/vm/flow_graph_optimizer.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_OPTIMIZER_H_
 #define VM_FLOW_GRAPH_OPTIMIZER_H_
 
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph.h"
 
@@ skipping 144 matching lines @@
   FlowGraph* flow_graph_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
 };
 
 
 class ParsedFunction;
 
 
 // Loop invariant code motion.
-class LICM : public AllStatic {
+class LICM : public ValueObject {
  public:
-  static void Optimize(FlowGraph* flow_graph);
+  explicit LICM(FlowGraph* flow_graph);
+
+  void Optimize();
 
  private:
-  static void Hoist(ForwardInstructionIterator* it,
-                    BlockEntryInstr* pre_header,
-                    Instruction* current);
+  FlowGraph* flow_graph() const { return flow_graph_; }
 
-  static void TryHoistCheckSmiThroughPhi(ForwardInstructionIterator* it,
-                                         BlockEntryInstr* header,
-                                         BlockEntryInstr* pre_header,
-                                         CheckSmiInstr* current);
+  void Hoist(ForwardInstructionIterator* it,
+             BlockEntryInstr* pre_header,
+             Instruction* current);
+
+  void TryHoistCheckSmiThroughPhi(ForwardInstructionIterator* it,
+                                  BlockEntryInstr* header,
+                                  BlockEntryInstr* pre_header,
+                                  CheckSmiInstr* current);
+
+  FlowGraph* const flow_graph_;
 };
 
 
 // A simple common subexpression elimination based
 // on the dominator tree.
 class DominatorBasedCSE : public AllStatic {
  public:
   // Return true, if the optimization changed the flow graph.
   // False, if nothing changed.
   static bool Optimize(FlowGraph* graph);
@@ skipping 62 matching lines @@
 
   // Worklists of blocks and definitions.
   GrowableArray<BlockEntryInstr*> block_worklist_;
   GrowableArray<Definition*> definition_worklist_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_