dart2js: add isConstantsHolder to Holder class.

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.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.js_emitter.program_builder;
 
 import '../js_emitter.dart' show computeMixinClass, Emitter;
 import '../model.dart';
 
 import '../../common.dart';
@@ skipping 82 matching lines @@
     // to check that the library has been loaded.
     _compiler.deferredLoadTask.allOutputUnits.forEach(
         _registry.registerOutputUnit);
     collector.outputClassLists.forEach(_registry.registerElements);
     collector.outputStaticLists.forEach(_registry.registerElements);
     collector.outputConstantLists.forEach(_registerConstants);
     collector.outputStaticNonFinalFieldLists.forEach(
         _registry.registerElements);
 
     // We always add the current isolate holder.
-    _registry.registerHolder(
-        namer.staticStateHolder, isStaticStateHolder: true);
+    _registerStaticStateHolder();
 
     // We need to run the native-preparation before we build the output. The
     // preparation code, in turn needs the classes to be set up.
     // We thus build the classes before building their containers.
     collector.outputClassLists.forEach((OutputUnit _, List<ClassElement> classes) {
       classes.forEach(_buildClass);
     });
 
     // Resolve the superclass references after we've processed all the classes.
     _classes.forEach((ClassElement element, Class c) {
@@ skipping 129 matching lines @@
     return staticNonFinalFields
         .map(_buildStaticField)
         .toList(growable: false);
   }
 
   StaticField _buildStaticField(Element element) {
     JavaScriptConstantCompiler handler = backend.constants;
     ConstantValue initialValue = handler.getInitialValueFor(element);
     // TODO(zarah): The holder should not be registered during building of
     // a static field.
-    _registry.registerHolder(namer.globalObjectForConstant(initialValue));
+    _registry.registerHolder(
+        namer.globalObjectForConstant(initialValue), isConstantsHolder: true);
     js.Expression code = _task.emitter.constantReference(initialValue);
     js.Name name = namer.globalPropertyName(element);
     bool isFinal = false;
     bool isLazy = false;
 
     // TODO(floitsch): we shouldn't update the registry in the middle of
-    // building a static field. (Note that the $ holder is already registered
-    // earlier).
+    // building a static field. (Note that the static-state holder was
+    // already registered earlier, and that we just call the register to get
+    // the holder-instance.
     return new StaticField(element,
-                           name, _registry.registerHolder(r'$'), code,
+                           name, _registerStaticStateHolder(), code,
                            isFinal, isLazy);
   }
 
   List<StaticField> _buildStaticLazilyInitializedFields(
       LibrariesMap librariesMap) {
     // TODO(floitsch): lazy fields should just be in their respective
     // libraries.
     if (librariesMap != _registry.mainLibrariesMap) {
       return const <StaticField>[];
     }
@@ skipping 11 matching lines @@
     js.Expression code = backend.generatedCode[element];
     // The code is null if we ended up not needing the lazily
     // initialized field after all because of constant folding
     // before code generation.
     if (code == null) return null;
 
     js.Name name = namer.globalPropertyName(element);
     bool isFinal = element.isFinal;
     bool isLazy = true;
     // TODO(floitsch): we shouldn't update the registry in the middle of
-    // building a static field. (Note that the $ holder is already registered
-    // earlier).
+    // building a static field. (Note that the static-state holder was
+    // already registered earlier, and that we just call the register to get
+    // the holder-instance.
     return new StaticField(element,
-                           name, _registry.registerHolder(r'$'), code,
+                           name, _registerStaticStateHolder(), code,
                            isFinal, isLazy);
   }
 
   List<Library> _buildLibraries(LibrariesMap librariesMap) {
     List<Library> libraries = new List<Library>(librariesMap.length);
     int count = 0;
     librariesMap.forEach((LibraryElement library, List<Element> elements) {
       libraries[count++] = _buildLibrary(library, elements);
     });
     return libraries;
@@ skipping 476 matching lines @@
 
   void _registerConstants(OutputUnit outputUnit,
                           Iterable<ConstantValue> constantValues) {
     // `constantValues` is null if an outputUnit doesn't contain any constants.
     if (constantValues == null) return;
     for (ConstantValue constantValue in constantValues) {
       _registry.registerConstant(outputUnit, constantValue);
       assert(!_constants.containsKey(constantValue));
       js.Name name = namer.constantName(constantValue);
       String constantObject = namer.globalObjectForConstant(constantValue);
-      Holder holder = _registry.registerHolder(constantObject);
+      Holder holder =
+          _registry.registerHolder(constantObject, isConstantsHolder: true);
       Constant constant = new Constant(name, holder, constantValue);
       _constants[constantValue] = constant;
     }
   }
+
+  Holder _registerStaticStateHolder() {
+    return _registry.registerHolder(
+        namer.staticStateHolder, isStaticStateHolder: true);
+  }
 }