Optimize functions containing try-catch.

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 26 matching lines @@
 
   // Returns true if any instructions were canonicalized away.
   bool Canonicalize();
 
   void EliminateDeadPhis();
 
   void SelectRepresentations();
 
   void InferSmiRanges();
 
+  void AnalyzeTryCatch();
+
   // Remove environments from the instructions which do not deoptimize.
   void EliminateEnvironments();
 
   virtual void VisitStaticCall(StaticCallInstr* instr);
   virtual void VisitInstanceCall(InstanceCallInstr* instr);
   virtual void VisitRelationalOp(RelationalOpInstr* instr);
   virtual void VisitEqualityCompare(EqualityCompareInstr* instr);
   virtual void VisitBranch(BranchInstr* instr);
   virtual void VisitStrictCompare(StrictCompareInstr* instr);
 
@@ skipping 281 matching lines @@
       Instruction* exit,
       AllocateObjectInstr* alloc,
       const Class& cls,
       const ZoneGrowableArray<const Field*>& fields);
 
   FlowGraph* flow_graph_;
 
   GrowableArray<MaterializeObjectInstr*> materializations_;
 };
 
+
+// Optimize spill stores inside try-blocks by identifying values that always
+// contain a single known constant at catch block entry.
+class TryCatchAnalyzer : public AllStatic {
+ public:
+  static void Optimize(FlowGraph* flow_graph);
+};
+
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_