Add a visitor for Elements

sdk/lib/_internal/compiler/implementation/ssa/builder.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 ssa;
 
 /**
  * A special element for the extra parameter taken by intercepted
  * methods. We need to override [Element.computeType] because our
  * optimizers may look at its declared type.
  */
 class InterceptedElement extends ElementX {
   final DartType type;
   InterceptedElement(this.type, String name, Element enclosing)
       : super(name, ElementKind.PARAMETER, enclosing);
 
   DartType computeType(Compiler compiler) => type;
+
+  accept(ElementVisitor visitor) => visitor.visitInterceptedElement(this);
 }
 
 class SsaBuilderTask extends CompilerTask {
   final CodeEmitterTask emitter;
   final JavaScriptBackend backend;
 
   String get name => 'SSA builder';
 
   SsaBuilderTask(JavaScriptBackend backend)
     : emitter = backend.emitter,
@@ skipping 1280 matching lines @@
     if ((function.isConstructor() || function.isGenerativeConstructorBody())
         && backend.classNeedsRti(enclosing)) {
       enclosing.typeVariables.forEach((TypeVariableType typeVariable) {
         HInstruction argument = compiledArguments[argumentIndex++];
         newLocalsHandler.updateLocal(typeVariable.element, argument);
       });
     }
     assert(argumentIndex == compiledArguments.length);
 
     // TODO(kasperl): Bad smell. We shouldn't be constructing elements here.
-    returnElement = new ElementX("result",
-                                 ElementKind.VARIABLE,
-                                 function);
+    returnElement = new VariableElementX.synthetic("result",
+        ElementKind.VARIABLE, function);
     newLocalsHandler.updateLocal(returnElement,
                                  graph.addConstantNull(compiler));
     elements = compiler.enqueuer.resolution.getCachedElements(function);
     assert(elements != null);
     returnType = signature.returnType;
     stack = <HInstruction>[];
     inliningStack.add(state);
     localsHandler = newLocalsHandler;
     return state;
   }
@@ skipping 4027 matching lines @@
     SubGraph bodyGraph = new SubGraph(startTryBlock, lastOpenedBlock);
     SubGraph catchGraph = null;
     HLocalValue exception = null;
 
     if (!node.catchBlocks.isEmpty) {
       localsHandler = new LocalsHandler.from(savedLocals);
       startCatchBlock = graph.addNewBlock();
       open(startCatchBlock);
       // TODO(kasperl): Bad smell. We shouldn't be constructing elements here.
       // Note that the name of this element is irrelevant.
-      Element element = new ElementX('exception',
-                                     ElementKind.PARAMETER,
-                                     currentElement);
+      Element element = new VariableElementX.synthetic('exception',
+          ElementKind.PARAMETER, currentElement);
       exception = new HLocalValue(element, backend.nonNullType);
       add(exception);
       HInstruction oldRethrowableException = rethrowableException;
       rethrowableException = exception;
 
       pushInvokeStatic(node, backend.getExceptionUnwrapper(), [exception]);
       HInvokeStatic unwrappedException = pop();
       tryInstruction.exception = exception;
       Link<Node> link = node.catchBlocks.nodes;
 
@@ skipping 573 matching lines @@
           new HSubGraphBlockInformation(elseBranch.graph));
 
     HBasicBlock conditionStartBlock = conditionBranch.block;
     conditionStartBlock.setBlockFlow(info, joinBlock);
     SubGraph conditionGraph = conditionBranch.graph;
     HIf branch = conditionGraph.end.last;
     assert(branch is HIf);
     branch.blockInformation = conditionStartBlock.blockFlow;
   }
 }