dart2js: add type lookup in the new emitter.

pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.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.
 
 library dart2js.new_js_emitter.model_emitter;
 
 import '../../dart2jslib.dart' show Compiler;
 import '../../js/js.dart' as js;
 import '../../js_backend/js_backend.dart' show
     JavaScriptBackend,
     Namer,
     ConstantEmitter;
 
 import 'package:_internal/compiler/js_lib/shared/embedded_names.dart' show
     DEFERRED_LIBRARY_URIS,
     DEFERRED_LIBRARY_HASHES,
     INITIALIZE_LOADED_HUNK,
     IS_HUNK_INITIALIZED,
-    IS_HUNK_LOADED;
+    IS_HUNK_LOADED,
+    GET_TYPE_FROM_NAME;
 
 import '../js_emitter.dart' show NativeGenerator;
 import '../model.dart';
 
 class ModelEmitter {
   final Compiler compiler;
   final Namer namer;
   final ConstantEmitter constantEmitter;
 
   JavaScriptBackend get backend => compiler.backend;
@@ skipping 98 matching lines @@
     // that covers the entire program.
 
     List<js.Statement> statements = [
         new js.ExpressionStatement(
             new js.VariableDeclarationList(holders.map((e) =>
                 new js.VariableInitialization(
                     new js.VariableDeclaration(e.name, allowRename: false),
                     new js.ObjectInitializer(const []))).toList())),
         js.js.statement('var holders = #', new js.ArrayInitializer(
             holders.map((e) => new js.VariableUse(e.name))
-                   .toList(growable: false)))
+                   .toList(growable: false))),
+        js.js.statement('var holdersMap = {}')
     ];
     return new js.Block(statements);
   }
 
   static js.Template get makeConstantListTemplate {
     // TODO(floitsch): remove hard-coded name.
     // TODO(floitsch): there is no harm in caching the template.
     return js.js.uncachedExpressionTemplate('makeConstList(#)');
   }
 
   js.Block emitEmbeddedGlobals(Map<String, List<Fragment>> loadMap) {
     List<js.Property> globals = <js.Property>[];
 
     if (loadMap.isNotEmpty) {
       globals.addAll(emitLoadUrisAndHashes(loadMap));
       globals.add(emitIsHunkLoadedFunction());
       globals.add(emitInitializeLoadedHunk());
     }
 
+    globals.add(emitGetTypeFromName());
     js.ObjectInitializer globalsObject = new js.ObjectInitializer(globals);
 
     List<js.Statement> statements =
         [new js.ExpressionStatement(
             new js.VariableDeclarationList(
                 [new js.VariableInitialization(
                     new js.VariableDeclaration("init", allowRename: false),
                     globalsObject)]))];
     return new js.Block(statements);
   }
@@ skipping 41 matching lines @@
         js.js("function(hash) { return !!$deferredInitializersGlobal[hash]; }");
     return new js.Property(js.string(IS_HUNK_LOADED), function);
   }
 
   js.Property emitInitializeLoadedHunk() {
     js.Expression function =
         js.js("function(hash) { eval($deferredInitializersGlobal[hash]); }");
     return new js.Property(js.string(INITIALIZE_LOADED_HUNK), function);
   }
 
+  js.Property emitGetTypeFromName() {
+    js.Expression function =
+            js.js( """function(name) {
+                        var holder = holders[holdersMap[name]];
+                        return holder[name];
+                      }""");
+    return new js.Property(js.string(GET_TYPE_FROM_NAME), function);
+  }
+
   js.Expression emitDeferredFragment(DeferredFragment fragment,
                                      List<Holder> holders) {
     // TODO(floitsch): initialize eager classes.
     // TODO(floitsch): the hash must depend on the output.
     int hash = this.hashCode;
     if (fragment.constants.isNotEmpty) {
       throw new UnimplementedError("constants in deferred units");
     }
     js.ArrayInitializer content =
         new js.ArrayInitializer(fragment.libraries.map(emitLibrary)
@@ skipping 179 matching lines @@
   function setupLibrary(library) {
     var statics = library[0];
     for (var i = 0; i < statics.length; i += 3) {
       var holderIndex = statics[i + 1];
       setupStatic(statics[i], holders[holderIndex], statics[i + 2]);
     }
 
     var classes = library[1];
     for (var i = 0; i < classes.length; i += 3) {
       var holderIndex = classes[i + 1];
+      holdersMap[classes[i]] = holderIndex;

[floitsch, 2015/01/23 10:46:31]

You can directly store the holder in the map.
That is: holdersMap[classes[i]] = holders[holderIndex]
Also makes the code above easier:

function(name) { return holdersMap[name][name]; }

[zarah, 2015/01/23 12:22:18]

Done.

       setupClass(classes[i], holders[holderIndex], classes[i + 2]);
     }
   }
 
   function setupLazyStatics(statics) {
     for (var i = 0; i < statics.length; i += 4) {
       var name = statics[i];
       var getterName = statics[i + 1];
       var holderIndex = statics[i + 2];
       var initializer = statics[i + 3];
@@ skipping 146 matching lines @@
 
   var end = Date.now();
   print('Setup: ' + (end - start) + ' ms.');
 
   #main();  // Start main.
 
 }(Date.now(), #code)
 }""";
 
 }