Merge CommonElements and BackendHelpers!

pkg/compiler/lib/src/ssa/interceptor_simplifier.dart

 // 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.
 
+import '../common_elements.dart' show CommonElements;
 import '../common/backend_api.dart' show BackendClasses;
 import '../constants/constant_system.dart';
 import '../constants/values.dart';
 import '../elements/entities.dart';
-import '../js_backend/backend_helpers.dart';
 import '../js_backend/interceptor_data.dart';
 import '../types/types.dart';
 import '../universe/selector.dart' show Selector;
 import '../world.dart' show ClosedWorld;
 import 'nodes.dart';
 import 'optimize.dart';
 
 /**
  * This phase simplifies interceptors in multiple ways:
  *
@@ skipping 11 matching lines @@
  * receiver of an intercepted call a candidate for being generated at use site.
  *
  * 5) Some HIs operations on an interceptor are replaced with a HIs version that
  * uses 'instanceof' rather than testing a type flag.
  *
  */
 class SsaSimplifyInterceptors extends HBaseVisitor
     implements OptimizationPhase {
   final String name = "SsaSimplifyInterceptors";
   final ClosedWorld closedWorld;
-  final BackendHelpers helpers;
   final InterceptorData interceptorData;
+  final CommonElements _commonElements;
   final ClassEntity enclosingClass;
   HGraph graph;
 
-  SsaSimplifyInterceptors(this.closedWorld, this.helpers, this.interceptorData,
-      this.enclosingClass);
+  SsaSimplifyInterceptors(this.closedWorld, this._commonElements,
+      this.interceptorData, this.enclosingClass);
 
   BackendClasses get backendClasses => closedWorld.backendClasses;
 
   ConstantSystem get constantSystem => closedWorld.constantSystem;
 
   void visitGraph(HGraph graph) {
     this.graph = graph;
     visitDominatorTree(graph);
   }
 
@@ skipping 43 matching lines @@
       return false;
     }
     if (receiver.canBeNull() &&
         interceptedClasses.contains(backendClasses.nullClass)) {
       // Need the JSNull interceptor.
       return false;
     }
 
     // All intercepted classes extend `Interceptor`, so if the receiver can't be
     // a class extending `Interceptor` then it can be called directly.
-    return new TypeMask.nonNullSubclass(helpers.jsInterceptorClass, closedWorld)
+    return new TypeMask.nonNullSubclass(
+            _commonElements.jsInterceptorClass, closedWorld)
         .isDisjoint(receiver.instructionType, closedWorld);
   }
 
   HInstruction tryComputeConstantInterceptor(
       HInstruction input, Set<ClassEntity> interceptedClasses) {
     if (input == graph.explicitReceiverParameter) {
       // If `explicitReceiverParameter` is set it means the current method is an
       // interceptor method, and `this` is the interceptor.  The caller just did
       // `getInterceptor(foo).currentMethod(foo)` to enter the current method.
       return graph.thisInstruction;
@@ skipping 299 matching lines @@
       instruction = new HInvokeDynamicMethod(
           selector, mask, inputs, node.instructionType, true);
     }
 
     HBasicBlock block = node.block;
     block.addAfter(node, instruction);
     block.rewrite(node, instruction);
     return true;
   }
 }