Towards compiling Hello World!

pkg/compiler/lib/src/compiler.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.
 
 library dart2js.compiler_base;
 
 import 'dart:async' show Future;
 
 import '../compiler_new.dart' as api;
 import 'backend_strategy.dart';
@@ skipping 592 matching lines @@
         globalInference.runGlobalTypeInference(
             mainFunction, closedWorld, closedWorldRefiner);
 
         if (stopAfterTypeInference) return;
 
         backend.onTypeInferenceComplete(globalInference.results);
 
         reporter.log('Compiling...');
         phase = PHASE_COMPILING;
 
-        Enqueuer codegenEnqueuer = enqueuer.createCodegenEnqueuer(closedWorld);
-        _codegenWorldBuilder = codegenEnqueuer.worldBuilder;
-        codegenEnqueuer.applyImpact(
-            backend.onCodegenStart(closedWorld, _codegenWorldBuilder));
+        Enqueuer codegenEnqueuer = startCodegen(closedWorld);
         if (compileAll) {
           libraryLoader.libraries.forEach((LibraryEntity library) {
             codegenEnqueuer.applyImpact(computeImpactForLibrary(library));
           });
         }
         processQueue(closedWorld.elementEnvironment, codegenEnqueuer,
             mainFunction, libraryLoader.libraries,
             onProgress: showCodegenProgress);
         codegenEnqueuer.logSummary(reporter.log);
 
         int programSize = backend.assembleProgram(closedWorld);
 
         if (options.dumpInfo) {
           dumpInfoTask.reportSize(programSize);
           dumpInfoTask.dumpInfo(closedWorld);
         }
 
         backend.onCodegenEnd();
 
         checkQueues(resolutionEnqueuer, codegenEnqueuer);
       });
 
+  Enqueuer startCodegen(ClosedWorld closedWorld) {
+    Enqueuer codegenEnqueuer = enqueuer.createCodegenEnqueuer(closedWorld);
+    _codegenWorldBuilder = codegenEnqueuer.worldBuilder;
+    codegenEnqueuer
+        .applyImpact(backend.onCodegenStart(closedWorld, _codegenWorldBuilder));
+    return codegenEnqueuer;
+  }
+
   /// Perform the steps needed to fully end the resolution phase.
   ClosedWorldRefiner closeResolution() {
     phase = PHASE_DONE_RESOLVING;
 
     ClosedWorld closedWorld = resolutionWorldBuilder.closeWorld();
     ClosedWorldRefiner closedWorldRefiner =
         backendStrategy.createClosedWorldRefiner(closedWorld);
     // Compute whole-program-knowledge that the backend needs. (This might
     // require the information computed in [world.closeWorld].)
     backend.onResolutionClosedWorld(closedWorld, closedWorldRefiner);
@@ skipping 936 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }