dart2js: Use frequency of occurence to sort metadata indices.

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 120 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<js.Expression> types =
-          program.metadataTypes[deferredUnit.outputUnit];
+      js.Expression types =
+          program.metadataTypesForOutputUnit(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 32 matching lines @@
     return '// Generated by dart2js, the Dart to JavaScript compiler$suffix.\n';
   }
 
   js.Statement emitMainFragment(Program program) {
     MainFragment fragment = program.fragments.first;
     List<js.Expression> elements = fragment.libraries.map(emitLibrary).toList();
     elements.add(
         emitLazilyInitializedStatics(fragment.staticLazilyInitializedFields));
     elements.add(emitConstants(fragment.constants));
 
-
     js.Expression code = new js.ArrayInitializer(elements);
 
     Map<String, dynamic> holes =
       {'deferredInitializer': emitDeferredInitializerGlobal(program.loadMap),
        'holders': emitHolders(program.holders),
        'tearOff': buildTearOffCode(backend),
        'parseFunctionDescriptor':
            js.js.statement(parseFunctionDescriptorBoilerplate,
                {'argumentCount': js.string(namer.requiredParameterField),
                 'defaultArgumentValues': js.string(namer.defaultValuesField),
@@ skipping 279 matching lines @@
     js.ArrayInitializer unparseExpressions(List<js.Expression> expressions) {
       if (expressions == null) expressions = <js.Expression>[];
       List<js.LiteralString> unparsedExpressions = expressions
           .map((expr) => unparse(compiler, expr, protectForEval: false))
           .toList();
       return new js.ArrayInitializer(unparsedExpressions);
     }
 
     List<js.Property> metadataGlobals = <js.Property>[];
 
-    js.ArrayInitializer unparsedMetadata = unparseExpressions(program.metadata);
-    metadataGlobals.add(new js.Property(js.string(lazyMetadataName),
-                                        unparsedMetadata));
-    metadataGlobals.add(new js.Property(js.string(METADATA),
-                                        new js.ArrayInitializer([])));
+    js.Property createGlobal(js.Expression metadata, String global) {
+      return new js.Property(js.string(global), metadata);
+    }
 
-    List<js.Expression> types =
-        program.metadataTypes[program.fragments.first.outputUnit];
-    metadataGlobals.add(new js.Property(js.string(TYPES),
-                                        unparseExpressions(types)));
+    metadataGlobals.add(createGlobal(program.metadata, METADATA));
+    js.Expression types =
+        program.metadataTypesForOutputUnit(program.mainFragment.outputUnit);
+    metadataGlobals.add(createGlobal(types, TYPES));
 
     return metadataGlobals;
   }
 
-  js.Expression emitDeferredFragment(List<js.Expression> types,
+  js.Expression emitDeferredFragment(js.Expression deferredTypes,
                                      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 = new js.Block([
         emitStaticNonFinalFields(fragment.staticNonFinalFields),
         emitEagerClassInitializations(fragment.libraries)]);
 
 
     js.LiteralString immediateString = unparse(compiler, immediateCode);
 
-    js.Expression deferredTypes = (types == null)
-        ? js.string("[]")
-        : 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.
   static final String constantsDescription =
@@ skipping 706 matching lines @@
 
   var end = Date.now();
   // print('Setup: ' + (end - start) + ' ms.');
 
   #invokeMain;  // Start main.
 
 }(Date.now(), #code)
 }""";
 
 }