VM: Propagate non-nullness from instance calls.

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, 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 RUNTIME_VM_INTERMEDIATE_LANGUAGE_H_
 #define RUNTIME_VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 2391 matching lines @@
 
  private:
   const ICData::DeoptReasonId deopt_reason_;
 
   DISALLOW_COPY_AND_ASSIGN(DeoptimizeInstr);
 };
 
 
 class RedefinitionInstr : public TemplateDefinition<1, NoThrow> {
  public:
-  explicit RedefinitionInstr(Value* value) : type_(NULL) {
+  explicit RedefinitionInstr(Value* value) : constrained_type_(NULL) {
     SetInputAt(0, value);
   }
 
   DECLARE_INSTRUCTION(Redefinition)
 
   Value* value() const { return inputs_[0]; }
 
   virtual CompileType ComputeType() const;
   virtual bool RecomputeType();
 
-  void set_type(CompileType* type) { type_ = type; }
-  CompileType* type() const { return type_; }
+  virtual Definition* Canonicalize(FlowGraph* flow_graph);
+
+  void set_constrained_type(CompileType* type) { constrained_type_ = type; }
+  CompileType* constrained_type() const { return constrained_type_; }
 
   virtual bool CanDeoptimize() const { return false; }
   virtual EffectSet Dependencies() const { return EffectSet::None(); }
   virtual EffectSet Effects() const { return EffectSet::None(); }
 
  private:
-  CompileType* type_;
+  CompileType* constrained_type_;
   DISALLOW_COPY_AND_ASSIGN(RedefinitionInstr);
 };
 
 
 class ConstraintInstr : public TemplateDefinition<1, NoThrow> {
  public:
   ConstraintInstr(Value* value, Range* constraint)
       : constraint_(constraint), target_(NULL) {
     SetInputAt(0, value);
   }
@@ skipping 5599 matching lines @@
   LocationSummary* Name::MakeLocationSummary(Zone* zone, bool opt) const {     \
     UNIMPLEMENTED();                                                           \
     return NULL;                                                               \
   }                                                                            \
   void Name::EmitNativeCode(FlowGraphCompiler* compiler) { UNIMPLEMENTED(); }
 
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_INTERMEDIATE_LANGUAGE_H_