Remove support for non-ssa optimizing code generation.

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"
 
 namespace dart {
 
 template <typename T> class GrowableArray;
 
 class FlowGraphOptimizer : public FlowGraphVisitor {
  public:
-  FlowGraphOptimizer(const FlowGraph& flow_graph, bool use_ssa)
-      : FlowGraphVisitor(flow_graph.reverse_postorder()), use_ssa_(use_ssa) {}
+  explicit FlowGraphOptimizer(const FlowGraph& flow_graph)
+      : FlowGraphVisitor(flow_graph.reverse_postorder()) {}
   virtual ~FlowGraphOptimizer() {}
 
   void ApplyICData();
 
   void OptimizeComputations();
 
   virtual void VisitStaticCall(StaticCallComp* comp, BindInstr* instr);
   virtual void VisitInstanceCall(InstanceCallComp* comp, BindInstr* instr);
   virtual void VisitRelationalOp(RelationalOpComp* comp, BindInstr* instr);
   virtual void VisitEqualityCompare(EqualityCompareComp* comp,
@@ skipping 11 matching lines @@
   bool TryReplaceWithUnaryOp(BindInstr* instr,
                              InstanceCallComp* comp,
                              Token::Kind op_kind);
 
   bool TryInlineInstanceGetter(BindInstr* instr,
                                InstanceCallComp* comp);
   bool TryInlineInstanceSetter(BindInstr* instr, InstanceCallComp* comp);
 
   bool TryInlineInstanceMethod(BindInstr* instr, InstanceCallComp* comp);
 
-  bool use_ssa_;
-
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
 };
 
 
 // Analyze the generated flow graph. Currently only if it is a leaf
 // method, i.e., does not contain any calls to runtime or other Dart code.
 class FlowGraphAnalyzer : public ValueObject {
  public:
   explicit FlowGraphAnalyzer(const FlowGraph& flow_graph)
       : blocks_(flow_graph.reverse_postorder()), is_leaf_(false) {}
   virtual ~FlowGraphAnalyzer() {}
 
   void Analyze();
 
   bool is_leaf() const { return is_leaf_; }
 
  private:
   const GrowableArray<BlockEntryInstr*>& blocks_;
   bool is_leaf_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphAnalyzer);
 };
 
 
 class ParsedFunction;
 
 
 class FlowGraphTypePropagator : public FlowGraphVisitor {
  public:
-  explicit FlowGraphTypePropagator(const FlowGraph& flow_graph,
-                                   bool is_ssa)
+  explicit FlowGraphTypePropagator(const FlowGraph& flow_graph)
       : FlowGraphVisitor(flow_graph.reverse_postorder()),
         parsed_function_(flow_graph.parsed_function()),
-        is_ssa_(is_ssa),
         still_changing_(false) { }
   virtual ~FlowGraphTypePropagator() { }
 
   const ParsedFunction& parsed_function() const { return parsed_function_; }
 
   void PropagateTypes();
 
   virtual void VisitAssertAssignable(AssertAssignableComp* comp,
                                      BindInstr* instr);
   virtual void VisitAssertBoolean(AssertBooleanComp* comp, BindInstr* instr);
   virtual void VisitInstanceOf(InstanceOfComp* comp, BindInstr* instr);
 
   virtual void VisitGraphEntry(GraphEntryInstr* graph_entry);
   virtual void VisitJoinEntry(JoinEntryInstr* join_entry);
   virtual void VisitBind(BindInstr* bind);
   virtual void VisitPhi(PhiInstr* phi);
   virtual void VisitParameter(ParameterInstr* param);
   virtual void VisitPushArgument(PushArgumentInstr* bind);
 
  private:
   const ParsedFunction& parsed_function_;
-  const bool is_ssa_;  // TODO(regis): Remove once virtual frame backend is
-                       // removed.
   bool still_changing_;
   DISALLOW_COPY_AND_ASSIGN(FlowGraphTypePropagator);
 };
 
 
 class LocalCSE : public ValueObject {
  public:
   explicit LocalCSE(const FlowGraph& flow_graph)
       : blocks_(flow_graph.reverse_postorder()) { }
 
   void Optimize();
 
  private:
   const GrowableArray<BlockEntryInstr*>& blocks_;
 
   DISALLOW_COPY_AND_ASSIGN(LocalCSE);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_