dart2js: Measure time of individual optimization passes.

pkg/compiler/lib/src/ssa/optimize.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;
 
 abstract class OptimizationPhase {
   String get name;
   void visitGraph(HGraph graph);
 }
 
 class SsaOptimizerTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaOptimizerTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name => 'SSA optimizer';
   Compiler get compiler => backend.compiler;
   Map<HInstruction, Range> ranges = <HInstruction, Range>{};
 
   void optimize(CodegenWorkItem work, HGraph graph) {
     void runPhase(OptimizationPhase phase) {
-      phase.visitGraph(graph);
+      measureSubtask(phase.name, () => phase.visitGraph(graph));
       compiler.tracer.traceGraph(phase.name, graph);
       assert(graph.isValid());
     }
 
     ConstantSystem constantSystem = compiler.backend.constantSystem;
     JavaScriptItemCompilationContext context = work.compilationContext;
     bool trustPrimitives = compiler.trustPrimitives;
     measure(() {
       List<OptimizationPhase> phases = <OptimizationPhase>[
           // Run trivial instruction simplification first to optimize
@@ skipping 2318 matching lines @@
 
     keyedValues.forEach((receiver, values) {
       result.keyedValues[receiver] =
           new Map<HInstruction, HInstruction>.from(values);
     });
 
     result.nonEscapingReceivers.addAll(nonEscapingReceivers);
     return result;
   }
 }