dart2js cps: Maintain parent pointers instead of recomputing them.

pkg/compiler/lib/src/js_backend/codegen/task.dart

 // Copyright (c) 2014, 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.
 
 /// Generate code using the cps-based IR pipeline.
 library code_generator_task;
 
 import 'glue.dart';
 import 'codegen.dart';
 import 'unsugar.dart';
@@ skipping 103 matching lines @@
       tracer.traceGraph(title, irObject);
     }
   }
 
   void applyCpsPass(cps_opt.Pass pass, cps.FunctionDefinition cpsFunction) {
     cpsOptimizationTask.measureSubtask(pass.passName, () {
       pass.rewrite(cpsFunction);
     });
     traceGraph(pass.passName, cpsFunction);
     dumpTypedIr(pass.passName, cpsFunction);
-    assert(checkCpsIntegrity(cpsFunction));
+    assert(checkCpsIntegrity(cpsFunction, pass.passName));
   }
 
   cps.FunctionDefinition compileToCpsIr(AstElement element) {
     cps.FunctionDefinition cpsFunction = cpsBuilderTask.buildNode(element);
     if (cpsFunction == null) {
       if (cpsBuilderTask.bailoutMessage == null) {
         giveUp('unable to build cps definition of $element');
       } else {
         giveUp(cpsBuilderTask.bailoutMessage);
       }
     }
+    ParentVisitor.setParents(cpsFunction);
     traceGraph('IR Builder', cpsFunction);
     dumpTypedIr('IR Builder', cpsFunction);
     // Eliminating redundant phis before the unsugaring pass will make it
     // insert fewer getInterceptor calls.
     applyCpsPass(new RedundantPhiEliminator(), cpsFunction);
     applyCpsPass(new UnsugarVisitor(glue), cpsFunction);
     return cpsFunction;
   }
 
   static const Pattern PRINT_TYPED_IR_FILTER = null;
@@ skipping 23 matching lines @@
         return node is cps.Variable && node.type != null
             ? '$s:${formatTypeMask(node.type)}'
             : s;
       }
       DEBUG_MODE = true;
       print(';;; ==== After $passName ====');
       print(new SExpressionStringifier(printType).visit(cpsFunction));
     }
   }
 
-  static bool checkCpsIntegrity(cps.FunctionDefinition node) {
-    new CheckCpsIntegrity().check(node);
+  static bool checkCpsIntegrity(cps.FunctionDefinition node, String pass) {
+    new CheckCpsIntegrity().check(node, pass);
     return true; // So this can be used from assert().
   }
 
   cps.FunctionDefinition optimizeCpsIr(cps.FunctionDefinition cpsFunction) {
     TypeMaskSystem typeSystem = new TypeMaskSystem(compiler);
 
     applyCpsPass(new RedundantJoinEliminator(), cpsFunction);
     applyCpsPass(new RedundantPhiEliminator(), cpsFunction);
     applyCpsPass(new InsertRefinements(typeSystem), cpsFunction);
     applyCpsPass(new TypePropagator(compiler, typeSystem, this), cpsFunction);
@@ skipping 64 matching lines @@
         treeOptimizationTask]
       ..addAll(fallbackCompiler.tasks);
   }
 
   js.Node attachPosition(js.Node node, AstElement element) {
     return node.withSourceInformation(
         sourceInformationFactory.createBuilderForContext(element)
             .buildDeclaration(element));
   }
 }