Introduce type Bounds record

src/ast.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 339 matching lines @@
   // True iff the expression is a string literal.
   bool IsStringLiteral();
 
   // True iff the expression is the null literal.
   bool IsNullLiteral();
 
   // True iff the expression is the undefined literal.
   bool IsUndefinedLiteral();
 
   // Expression type bounds
-  Handle<Type> upper_type() { return upper_type_; }
-  Handle<Type> lower_type() { return lower_type_; }
-  void set_upper_type(Handle<Type> type) { upper_type_ = type; }
-  void set_lower_type(Handle<Type> type) { lower_type_ = type; }
+  Bounds bounds() { return bounds_; }
+  void set_bounds(Bounds bounds) { bounds_ = bounds; }
 
   // Type feedback information for assignments and properties.
   virtual bool IsMonomorphic() {
     UNREACHABLE();
     return false;
   }
   virtual SmallMapList* GetReceiverTypes() {
     UNREACHABLE();
     return NULL;
   }
@@ skipping 10 matching lines @@
 
   // TODO(rossberg): this should move to its own AST node eventually.
   virtual void RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle);
   byte to_boolean_types() const { return to_boolean_types_; }
 
   BailoutId id() const { return id_; }
   TypeFeedbackId test_id() const { return test_id_; }
 
  protected:
   explicit Expression(Isolate* isolate)
-      : upper_type_(Type::Any(), isolate),
-        lower_type_(Type::None(), isolate),
+      : bounds_(Type::None(), Type::Any(), isolate),
         id_(GetNextId(isolate)),
         test_id_(GetNextId(isolate)) {}
   void set_to_boolean_types(byte types) { to_boolean_types_ = types; }
 
  private:
-  Handle<Type> upper_type_;
-  Handle<Type> lower_type_;
+  Bounds bounds_;
   byte to_boolean_types_;
 
   const BailoutId id_;
   const TypeFeedbackId test_id_;
 };
 
 
 class BreakableStatement: public Statement {
  public:
   enum BreakableType {
@@ skipping 2800 matching lines @@
  private:
   Isolate* isolate_;
   Zone* zone_;
   Visitor visitor_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_