Avoid reparsing metadata expressions

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 '../../constants/values.dart' show ConstantValue, FunctionConstantValue;
 import '../../dart2jslib.dart' show Compiler;
 import '../../dart_types.dart' show DartType;
 import '../../elements/elements.dart' show ClassElement, FunctionElement;
@@ skipping 116 matching lines @@
   int emitProgram(Program program) {
     List<Fragment> fragments = program.fragments;
     MainFragment mainFragment = fragments.first;
 
     int totalSize = 0;
 
     // We have to emit the deferred fragments first, since we need their
     // deferred hash (which depends on the output) when emitting the main
     // fragment.
     fragments.skip(1).forEach((DeferredFragment deferredUnit) {
-      List<String> types = program.metadataTypes[deferredUnit.outputUnit];
+      List<js.Expression> types =
+          program.metadataTypes[deferredUnit.outputUnit];
       js.Expression ast = emitDeferredFragment(types, deferredUnit,
                                                program.holders);
       String code = js.prettyPrint(ast, compiler).getText();
       totalSize += code.length;
       compiler.outputProvider(deferredUnit.outputFileName, deferredExtension)
           ..add(code)
           ..close();
     });
 
     js.Statement mainAst = emitMainFragment(program);
@@ skipping 262 matching lines @@
 
   js.Property emitGetTypeFromName() {
     js.Expression function =
         js.js( """function(name) {
                     return holdersMap[name][name].ensureResolved();
                   }""");
     return new js.Property(js.string(GET_TYPE_FROM_NAME), function);
   }
 
   List<js.Property> emitMetadata(Program program) {
-
     List<js.Property> metadataGlobals = <js.Property>[];
-
-    js.Property createGlobal(List<String> list, String global) {
-      String listAsString = "[${list.join(",")}]";
-      js.Expression metadata =
-                js.js.uncachedExpressionTemplate(listAsString).instantiate([]);
-      return new js.Property(js.string(global), metadata);
-    }
-
-    metadataGlobals.add(createGlobal(program.metadata, METADATA));
-    List<String> types =
+    metadataGlobals.add(new js.Property(
+        js.string(METADATA), new js.ArrayInitializer(program.metadata)));
+    List<js.Expression> types =
         program.metadataTypes[program.fragments.first.outputUnit];
-    if (types == null) types = <String>[];
-    metadataGlobals.add(createGlobal(types, TYPES));
+    if (types == null) types = <js.Expression>[];
+    metadataGlobals.add(new js.Property(
+        js.string(TYPES), new js.ArrayInitializer(types)));
 
     return metadataGlobals;
   }
 
-  js.Expression emitDeferredFragment(List<String> types,
+  js.Expression emitDeferredFragment(List<js.Expression> types,
                                      DeferredFragment fragment,
                                      List<Holder> holders) {
     // TODO(floitsch): initialize eager classes.
     // TODO(floitsch): the hash must depend on the output.
     int hash = fragment.hashCode;
 
     List<js.Expression> deferredCode =
         fragment.libraries.map(emitLibrary).toList();
 
     deferredCode.add(
         emitLazilyInitializedStatics(fragment.staticLazilyInitializedFields));
 
     deferredCode.add(emitConstants(fragment.constants));
 
     js.ArrayInitializer deferredArray = new js.ArrayInitializer(deferredCode);
 
     // This is the code that must be evaluated after all deferred classes have
     // been setup.
     js.Statement immediateCode =
         emitEagerClassInitializations(fragment.libraries);
 
     js.LiteralString immediateString = unparse(compiler, immediateCode);
 
     js.Expression deferredTypes = types == null
         ? js.string("[]")
-        : js.string("[${types.join(",")}]");
+        : unparse(compiler, new js.ArrayInitializer(types));
 
     js.ArrayInitializer hunk =
         new js.ArrayInitializer([deferredArray, immediateString,
                                  deferredTypes]);
 
     return js.js("$deferredInitializersGlobal[$hash] = #", hunk);
   }
 
   // This string should be referenced wherever JavaScript code makes assumptions
   // on the constants format.
@@ skipping 700 matching lines @@
 
   var end = Date.now();
   // print('Setup: ' + (end - start) + ' ms.');
 
   #invokeMain;  // Start main.
 
 }(Date.now(), #code)
 }""";
 
 }