Compute [WorldImpact] for main method as entrypoint

pkg/compiler/lib/src/js_backend/backend.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 js_backend.backend;
 
 import 'dart:async' show Future;
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
 
@@ skipping 41 matching lines @@
 import '../universe/world_builder.dart';
 import '../universe/use.dart'
     show DynamicUse, StaticUse, StaticUseKind, TypeUse, TypeUseKind;
 import '../universe/world_impact.dart'
     show
         ImpactStrategy,
         ImpactUseCase,
         TransformedWorldImpact,
         WorldImpact,
         WorldImpactBuilder,
+        WorldImpactBuilderImpl,
         WorldImpactVisitor,
         StagedWorldImpactBuilder;
 import '../util/util.dart';
 import '../world.dart' show ClosedWorld;
 import 'backend_helpers.dart';
 import 'backend_impact.dart';
 import 'backend_serialization.dart' show JavaScriptBackendSerialization;
 import 'checked_mode_helpers.dart';
 import 'constant_handler_javascript.dart';
 import 'custom_elements_analysis.dart';
@@ skipping 2498 matching lines @@
   FunctionElement helperForMissingMain() => helpers.missingMain;
 
   FunctionElement helperForMainArity() => helpers.mainHasTooManyParameters;
 
   void forgetElement(Element element) {
     constants.forgetElement(element);
     constantCompilerTask.dartConstantCompiler.forgetElement(element);
     aliasedSuperMembers.remove(element);
   }
 
-  void registerMainHasArguments(Enqueuer enqueuer) {
-    // If the main method takes arguments, this compilation could be the target
-    // of Isolate.spawnUri. Strictly speaking, that can happen also if main
-    // takes no arguments, but in this case the spawned isolate can't
-    // communicate with the spawning isolate.
-    enqueuer.enableIsolateSupport();
+  @override
+  WorldImpact computeMainImpact(Enqueuer enqueuer, MethodElement mainMethod) {
+    WorldImpactBuilderImpl mainImpact = new WorldImpactBuilderImpl();
+    if (mainMethod.parameters.isNotEmpty) {
+      mainImpact.registerTypeUse(
+          new TypeUse.instantiation(backendClasses.listImplementation.rawType));
+      mainImpact.registerTypeUse(new TypeUse.instantiation(
+          backendClasses.stringImplementation.rawType));
+      mainImpact.registerStaticUse(
+          new StaticUse.staticInvoke(mainMethod, CallStructure.TWO_ARGS));
+
+      // If the main method takes arguments, this compilation could be the
+      // target of Isolate.spawnUri. Strictly speaking, that can happen also if
+      // main takes no arguments, but in this case the spawned isolate can't
+      // communicate with the spawning isolate.
+      enqueuer.enableIsolateSupport();
+    }
+    mainImpact.registerStaticUse(
+        new StaticUse.staticInvoke(mainMethod, CallStructure.NO_ARGS));
+    return mainImpact;
   }
 
   /// Returns the filename for the output-unit named [name].
   ///
   /// The filename is of the form "<main output file>_<name>.part.js".
   /// If [addExtension] is false, the ".part.js" suffix is left out.
   String deferredPartFileName(String name, {bool addExtension: true}) {
     assert(name != "");
     String outPath = compiler.options.outputUri != null
         ? compiler.options.outputUri.path
@@ skipping 682 matching lines @@
   ClassElement get mapImplementation => helpers.mapLiteralClass;
   ClassElement get constMapImplementation => helpers.constMapLiteralClass;
   ClassElement get typeImplementation => helpers.typeLiteralClass;
   ClassElement get boolImplementation => helpers.jsBoolClass;
   ClassElement get nullImplementation => helpers.jsNullClass;
   ClassElement get syncStarIterableImplementation => helpers.syncStarIterable;
   ClassElement get asyncFutureImplementation => helpers.futureImplementation;
   ClassElement get asyncStarStreamImplementation => helpers.controllerStream;
   ClassElement get functionImplementation => helpers.coreClasses.functionClass;
 }