dart2js cleanup: remove unused imports and variables

pkg/compiler/lib/src/ssa/codegen.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.
 
 import '../common.dart';
 import '../common/codegen.dart' show CodegenRegistry, CodegenWorkItem;
 import '../common/tasks.dart' show CompilerTask;
 import '../compiler.dart' show Compiler;
 import '../constants/constant_system.dart';
 import '../constants/values.dart';
 import '../core_types.dart' show CoreClasses;
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../io/source_information.dart';
 import '../js/js.dart' as js;
 import '../js_backend/backend_helpers.dart' show BackendHelpers;
 import '../js_backend/js_backend.dart';
-import '../js_emitter/js_emitter.dart' show CodeEmitterTask, NativeEmitter;
+import '../js_emitter/js_emitter.dart' show NativeEmitter;
 import '../native/native.dart' as native;
 import '../types/types.dart';
 import '../universe/call_structure.dart' show CallStructure;
 import '../universe/selector.dart' show Selector;
 import '../universe/use.dart' show DynamicUse, StaticUse, TypeUse;
 import '../util/util.dart';
-import '../world.dart' show ClassWorld, World;
-
+import '../world.dart' show ClassWorld;
+import 'codegen_helpers.dart';
 import 'nodes.dart';
-import 'codegen_helpers.dart';
 import 'variable_allocator.dart';
 
 class SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   final SourceInformationStrategy sourceInformationFactory;
 
   SsaCodeGeneratorTask(JavaScriptBackend backend, this.sourceInformationFactory)
       : this.backend = backend,
         super(backend.compiler);
 
@@ skipping 1567 matching lines @@
         .withSourceInformation(node.sourceInformation));
     registry.registerStaticUse(new StaticUse.constructorBodyInvoke(
         node.element, new CallStructure.unnamed(arguments.length)));
   }
 
   void visitOneShotInterceptor(HOneShotInterceptor node) {
     List<js.Expression> arguments = visitArguments(node.inputs);
     var isolate = new js.VariableUse(
         backend.namer.globalObjectFor(helpers.interceptorsLibrary));
     Selector selector = node.selector;
-    TypeMask mask = getOptimizedSelectorFor(node, selector, node.mask);
     js.Name methodName = backend.registerOneShotInterceptor(selector);
     push(js
         .propertyCall(isolate, methodName, arguments)
         .withSourceInformation(node.sourceInformation));
     if (selector.isGetter) {
       registerGetter(node);
     } else if (selector.isSetter) {
       registerSetter(node);
     } else {
       registerMethodInvoke(node);
@@ skipping 548 matching lines @@
     } else {
       generateThrowWithHelper(
           helpers.throwIndexOutOfRangeException, [node.array, node.index]);
     }
   }
 
   void generateThrowWithHelper(Element helper, argument,
       {SourceInformation sourceInformation}) {
     js.Expression jsHelper = backend.emitter.staticFunctionAccess(helper);
     List arguments = [];
-    var location;
     if (argument is List) {
-      location = argument[0];
       argument.forEach((instruction) {
         use(instruction);
         arguments.add(pop());
       });
     } else {
-      location = argument;
       use(argument);
       arguments.add(pop());
     }
     registry.registerStaticUse(new StaticUse.staticInvoke(
         helper, new CallStructure.unnamed(arguments.length)));
     js.Call value = new js.Call(jsHelper, arguments.toList(growable: false),
         sourceInformation: sourceInformation);
     // BUG(4906): Using throw/return here adds to the size of the generated code
     // but it has the advantage of explicitly telling the JS engine that
     // this code path will terminate abruptly. Needs more work.
@@ skipping 693 matching lines @@
     registry.registerStaticUse(new StaticUse.staticInvoke(
         helper, new CallStructure.unnamed(argumentCount)));
     return backend.emitter.staticFunctionAccess(helper);
   }
 
   @override
   void visitRef(HRef node) {
     visit(node.value);
   }
 }