Redo "Dummy receiver optimization"

sdk/lib/_internal/compiler/implementation/constants.dart

 // 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.
 
 part of dart2js;
 
 abstract class ConstantVisitor<R> {
   R visitFunction(FunctionConstant constant);
   R visitNull(NullConstant constant);
   R visitInt(IntConstant constant);
   R visitDouble(DoubleConstant constant);
   R visitTrue(TrueConstant constant);
   R visitFalse(FalseConstant constant);
   R visitString(StringConstant constant);
   R visitList(ListConstant constant);
   R visitMap(MapConstant constant);
   R visitConstructed(ConstructedConstant constant);
   R visitType(TypeConstant constant);
   R visitInterceptor(InterceptorConstant constant);
+  R visitDummyReceiver(DummyReceiverConstant constant);
 }
 
 abstract class Constant {
   const Constant();
 
   bool isNull() => false;
   bool isBool() => false;
   bool isTrue() => false;
   bool isFalse() => false;
   bool isInt() => false;
   bool isDouble() => false;
   bool isNum() => false;
   bool isString() => false;
   bool isList() => false;
   bool isMap() => false;
   bool isConstructedObject() => false;
   bool isFunction() => false;
   /** Returns true if the constant is null, a bool, a number or a string. */
   bool isPrimitive() => false;
   /** Returns true if the constant is a list, a map or a constructed object. */
   bool isObject() => false;
   bool isType() => false;
   bool isSentinel() => false;
   bool isInterceptor() => false;
+  bool isDummyReceiver() => false;
 
   bool isNaN() => false;
   bool isMinusZero() => false;
 
   // TODO(johnniwinther): Replace with a 'type' getter.
   DartType computeType(Compiler compiler);
 
   ti.TypeMask computeMask(Compiler compiler);
 
   List<Constant> getDependencies();
@@ skipping 477 matching lines @@
 
   ti.TypeMask computeMask(Compiler compiler) {
     return compiler.typesTask.nonNullType;
   }
 
   String toString() {
     return 'InterceptorConstant(${Error.safeToString(dispatchedType)})';
   }
 }
 
+class DummyReceiverConstant extends Constant {
+  final ti.TypeMask typeMask;
+
+  DummyReceiverConstant(this.typeMask);
+
+  bool isDummyReceiver() => true;
+
+  bool operator ==(other) {
+    return other is DummyReceiverConstant
+        && typeMask == other.typeMask;
+  }
+
+  get hashCode => typeMask.hashCode;
+
+  List<Constant> getDependencies() => const <Constant>[];
+
+  accept(ConstantVisitor visitor) => visitor.visitDummyReceiver(this);
+
+  DartType computeType(Compiler compiler) => compiler.types.dynamicType;
+
+  ti.TypeMask computeMask(Compiler compiler) => typeMask;
+
+  String toString() {
+    return 'DummyReceiverConstant($typeMask)';
+  }
+}
+
 class ConstructedConstant extends ObjectConstant {
   final List<Constant> fields;
   final int hashCode;
 
   ConstructedConstant(DartType type, List<Constant> fields)
     : this.fields = fields,
       hashCode = computeHash(type, fields),
       super(type) {
     assert(type != null);
   }
@@ skipping 53 matching lines @@
       if (i > 0) sb.write(',');
       sb.write(Error.safeToString(field.name));
       sb.write('=');
       sb.write(Error.safeToString(value));
       i++;
     });
     sb.write('))');
     return sb.toString();
   }
 }