Implement Symbol correctly in dart2js.

dart/sdk/lib/_internal/compiler/implementation/compiler.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.
 
 part of dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 288 matching lines @@
   ClassElement boolClass;
   ClassElement numClass;
   ClassElement intClass;
   ClassElement doubleClass;
   ClassElement stringClass;
   ClassElement functionClass;
   ClassElement nullClass;
   ClassElement listClass;
   ClassElement typeClass;
   ClassElement mapClass;
+  ClassElement symbolClass;
+
+  // Initialized after mirrorSystemClass has been resolved.
+  FunctionElement symbolConstructor;
+
+  // Initialized when dart:mirrors is loaded.
+  ClassElement mirrorSystemClass;
+
+  // Initialized after mirrorSystemClass has been resolved.
+  FunctionElement mirrorSystemGetNameFunction;
+
+  // Initialized when dart:_collection-dev is loaded.
+  ClassElement symbolImplementationClass;
+
+  // Initialized when symbolImplementationClass has been resolved.
+  FunctionElement symbolValidatedConstructor;
+
   ClassElement jsInvocationMirrorClass;
   /// Document class from dart:mirrors.
   ClassElement documentClass;
   Element assertMethod;
   Element identicalFunction;
   Element functionApplyMethod;
   Element invokeOnMethod;
   Element createInvocationMirrorElement;
 
   Element get currentElement => _currentElement;
@@ skipping 59 matching lines @@
       const SourceString('startRootIsolate');
 
   final Selector iteratorSelector =
       new Selector.getter(const SourceString('iterator'), null);
   final Selector currentSelector =
       new Selector.getter(const SourceString('current'), null);
   final Selector moveNextSelector =
       new Selector.call(const SourceString('moveNext'), null, 0);
   final Selector noSuchMethodSelector = new Selector.call(
       Compiler.NO_SUCH_METHOD, null, Compiler.NO_SUCH_METHOD_ARG_COUNT);
+  final Selector symbolValidatedConstructorSelector = new Selector.call(
+      const SourceString('validated'), null, 1);
 
   bool enabledNoSuchMethod = false;
   bool enabledRuntimeType = false;
   bool enabledFunctionApply = false;
   bool enabledInvokeOn = false;
 
   Stopwatch progress;
 
   static const int PHASE_SCANNING = 0;
   static const int PHASE_RESOLVING = 1;
@@ skipping 211 matching lines @@
    */
   void onLibraryScanned(LibraryElement library, Uri uri) {
     if (dynamicClass != null) {
       // When loading the built-in libraries, dynamicClass is null. We
       // take advantage of this as core imports js_helper and sees [dynamic]
       // this way.
       withCurrentElement(dynamicClass, () {
         library.addToScope(dynamicClass, this);
       });
     }
+    if (uri == Uri.parse('dart:mirrors')) {
+      mirrorSystemClass = library.find(const SourceString('MirrorSystem'));
+    } else if (uri == Uri.parse('dart:_collection-dev')) {
+      symbolImplementationClass = library.find(const SourceString('Symbol'));
+    }
+  }
+
+  void onClassResolved(ClassElement cls) {
+    if (mirrorSystemClass == cls) {
+      mirrorSystemGetNameFunction =
+        cls.lookupLocalMember(const SourceString('getName'));
+    } else if (symbolClass == cls) {
+      symbolConstructor = cls.constructors.head;
+    } else if (symbolImplementationClass == cls) {
+      symbolValidatedConstructor = symbolImplementationClass.lookupConstructor(
+          symbolValidatedConstructorSelector);
+    }
   }
 
   LibraryElement scanBuiltinLibrary(String filename);
 
   void initializeSpecialClasses() {
     final List missingCoreClasses = [];
     ClassElement lookupCoreClass(String name) {
       ClassElement result = coreLibrary.find(new SourceString(name));
       if (result == null) {
         missingCoreClasses.add(name);
       }
       return result;
     }
     objectClass = lookupCoreClass('Object');
     boolClass = lookupCoreClass('bool');
     numClass = lookupCoreClass('num');
     intClass = lookupCoreClass('int');
     doubleClass = lookupCoreClass('double');
     stringClass = lookupCoreClass('String');
     functionClass = lookupCoreClass('Function');
     listClass = lookupCoreClass('List');
     typeClass = lookupCoreClass('Type');
     mapClass = lookupCoreClass('Map');
     if (!missingCoreClasses.isEmpty) {
       internalErrorOnElement(coreLibrary,
           'dart:core library does not contain required classes: '
           '$missingCoreClasses');
     }
 
+    // The Symbol class may not exist during unit testing.
+    // TODO(ahe): It is possible that we have to require the presence
+    // of Symbol as we change how we implement noSuchMethod.
+    symbolClass = lookupCoreClass('Symbol');
+
     final List missingHelperClasses = [];
     ClassElement lookupHelperClass(String name) {
       ClassElement result = jsHelperLibrary.find(new SourceString(name));
       if (result == null) {
         missingHelperClasses.add(name);
       }
       return result;
     }
     jsInvocationMirrorClass = lookupHelperClass('JSInvocationMirror');
     closureClass = lookupHelperClass('Closure');
@@ skipping 348 matching lines @@
   }
 
   // TODO(ahe): Rename to reportError when that method has been removed.
   void reportErrorCode(Spannable node, MessageKind errorCode,
                        [Map arguments = const {}]) {
     reportMessage(spanFromSpannable(node),
                   errorCode.error(arguments),
                   api.Diagnostic.ERROR);
   }
 
+  // TODO(ahe): Rename to reportWarning when that method has been removed.
+  void reportWarningCode(Spannable node, MessageKind errorCode,
+                         [Map arguments = const {}]) {
+    reportMessage(spanFromSpannable(node),
+                  errorCode.error(arguments),
+                  api.Diagnostic.WARNING);
+  }
+
   void reportMessage(SourceSpan span, Diagnostic message, api.Diagnostic kind) {
     // TODO(ahe): The names Diagnostic and api.Diagnostic are in
     // conflict. Fix it.
     reportDiagnostic(span, "$message", kind);
   }
 
   /// Returns true if a diagnostic was emitted.
   bool onDeprecatedFeature(Spannable span, String feature) {
     if (currentElement == null)
       throw new SpannableAssertionFailure(span, feature);
@@ skipping 253 matching lines @@
 
   void close() {}
 
   toString() => name;
 
   /// Convenience method for getting an [api.CompilerOutputProvider].
   static NullSink outputProvider(String name, String extension) {
     return new NullSink('$name.$extension');
   }
 }