Implement MirrorUsed.targets for libraries

dart/sdk/lib/_internal/compiler/implementation/js_backend/backend.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 js_backend;
 
 class JavaScriptItemCompilationContext extends ItemCompilationContext {
   final Set<HInstruction> boundsChecked;
 
   JavaScriptItemCompilationContext()
@@ skipping 302 matching lines @@
   final List<Dependency> metadataInstantiatedTypes = <Dependency>[];
 
   /// List of elements used from metadata.  If metadata must be preserved,
   /// these elements must be compiled.
   final List<Element> metadataStaticUse = <Element>[];
 
   /// List of tear-off functions referenced from metadata.  If metadata must be
   /// preserved, these elements must be compiled.
   final List<FunctionElement> metadataGetOfStaticFunction = <FunctionElement>[];
 
+  /// List of symbols that the user has requested for reflection.
+  final Set<String> symbolsUsed = new Set<String>();
+
+  /// List of elements that the user has requested for reflection.
+  final Set<Element> targetsUsed = new Set<Element>();
+
+  /// List of annotations provided by user that indicate that the annotated
+  /// element must be retained.
+  final Set<Element> metaTargetsUsed = new Set<Element>();

[Johnni Winther, 2013/07/30 11:15:09]

Isn't this a list of the annotated elements and not of the annotations
themselves?

[ahe, 2013/07/30 12:05:45]

No. This is a list of classes that can be used as annotations. I think this
works best for the enqueuer.

+
   JavaScriptBackend(Compiler compiler, bool generateSourceMap, bool disableEval)
       : namer = determineNamer(compiler),
         oneShotInterceptors = new Map<String, Selector>(),
         interceptedElements = new Map<SourceString, Set<Element>>(),
         rti = new RuntimeTypes(compiler),
         specializedGetInterceptors = new Map<String, Set<ClassElement>>(),
         super(compiler, JAVA_SCRIPT_CONSTANT_SYSTEM) {
     emitter = disableEval
         ? new CodeEmitterNoEvalTask(compiler, namer, generateSourceMap)
         : new CodeEmitterTask(compiler, namer, generateSourceMap);
@@ skipping 1106 matching lines @@
     }
   }
 
   void registerMetadataGetOfStaticFunction(FunctionElement element) {
     if (mustRetainMetadata) {
       compiler.constantHandler.registerGetOfStaticFunction(element);
     } else {
       metadataGetOfStaticFunction.add(element);
     }
   }
+
+  void registerMirrorUsage(Set<String> symbols,
+                           Set<Element> targets,
+                           Set<Element> metaTargets) {
+    if (symbols != null) symbolsUsed.addAll(symbols);
+    if (targets != null) {
+      for (Element element in targets) {
+        // TODO(ahe): Implement finer granularity.
+        targetsUsed.add(element.getLibrary());
+      }
+    }
+    if (metaTargets != null) metaTargetsUsed.addAll(metaTargets);
+  }
+
+  bool isNeededForReflection(Element element) {
+    // TODO(ahe): Implement this.
+    if (!metaTargetsUsed.isEmpty) return true;
+    if (targetsUsed.contains(element.getLibrary())) return true;
+    return false;
+  }
 }
 
 /// Records that [type] is used by [user.element].
 class Dependency {
   final DartType type;
   final TreeElements user;
 
   const Dependency(this.type, this.user);
 }