Emit declarations for typedefs that are needed by reflection.

sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
index b1dbdc374d49a83732eab23b100552a4eb277118..41b74735eeacf7362c9511096c590b4d34d35930 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
@@ -55,6 +55,8 @@ class CodeEmitterTask extends CompilerTask {
   // TODO(ngeoffray): remove this field.
   Set<ClassElement> instantiatedClasses;
 
+  List<TypedefElement> typedefsNeededForReflection;
+
   JavaScriptBackend get backend => compiler.backend;
   TypeVariableHandler get typeVariableHandler => backend.typeVariableHandler;
 
@@ -63,9 +65,12 @@ class CodeEmitterTask extends CompilerTask {
   String get n => compiler.enableMinification ? "" : "\n";
   String get N => compiler.enableMinification ? "\n" : ";\n";
 
+  CodeBuffer getBuffer(OutputUnit outputUnit) {
+    return outputBuffers.putIfAbsent(outputUnit, () => new CodeBuffer());
+  }
+
   CodeBuffer get mainBuffer {
-    return outputBuffers.putIfAbsent(compiler.deferredLoadTask.mainOutputUnit,
-        () => new CodeBuffer());
+    return getBuffer(compiler.deferredLoadTask.mainOutputUnit);
   }
 
   /**
@@ -752,6 +757,8 @@ class CodeEmitterTask extends CompilerTask {
       ClassElement cls = element;
       if (cls.isUnnamedMixinApplication) return null;
       return cls.name;
+    } else if (element.isTypedef) {
+      return element.name;
     }
     throw compiler.internalError(element,
         'Do not know how to reflect on this $element.');
@@ -861,7 +868,7 @@ class CodeEmitterTask extends CompilerTask {
     for (Element element in Elements.sortedByPosition(elements)) {
       ClassBuilder builder = new ClassBuilder(element, namer);
       containerBuilder.addMember(element, builder);
-      getElementDecriptor(element).properties.addAll(builder.properties);
+      getElementDescriptor(element).properties.addAll(builder.properties);
     }
   }
 
@@ -1149,10 +1156,15 @@ class CodeEmitterTask extends CompilerTask {
     }
   }
 
-  /**
-   * Compute all the classes that must be emitted.
-   */
-  void computeNeededClasses() {
+  /// Compute all the classes and typedefs that must be emitted.
+  void computeNeededDeclarations() {
+    // Compute needed typedefs.
+    typedefsNeededForReflection = Elements.sortedByPosition(
+        compiler.world.allTypedefs
+            .where(backend.isAccessibleByReflection)
+            .toList());
+
+    // Compute needed classes.
     instantiatedClasses =
         compiler.codegenWorld.instantiatedClasses.where(computeClassFilter())
             .toSet();
@@ -1311,26 +1323,21 @@ class CodeEmitterTask extends CompilerTask {
         uri = relativize(compiler.outputUri, library.canonicalUri, false);
       }
     }
+    Map<OutputUnit, ClassBuilder> descriptors = elementDescriptors[library];
     String libraryName =
         (!compiler.enableMinification || backend.mustRetainLibraryNames) ?
         library.getLibraryName() :
         "";
-    Map<OutputUnit, ClassBuilder> descriptors =
-        elementDescriptors[library];
 
     for (OutputUnit outputUnit in compiler.deferredLoadTask.allOutputUnits) {
-      ClassBuilder descriptor =
-          descriptors.putIfAbsent(outputUnit,
-                                  () => new ClassBuilder(library, namer));
-      if (descriptor.properties.isEmpty) continue;
-      bool isDeferred =
-          outputUnit != compiler.deferredLoadTask.mainOutputUnit;
+      if (!descriptors.containsKey(outputUnit)) continue;
+
+      ClassBuilder descriptor = descriptors[outputUnit];
       jsAst.Fun metadata = metadataEmitter.buildMetadataFunction(library);
 
-      jsAst.ObjectInitializer initializers =
-          descriptor.toObjectInitializer();
-      CodeBuffer outputBuffer =
-          outputBuffers.putIfAbsent(outputUnit, () => new CodeBuffer());
+      jsAst.ObjectInitializer initializers = descriptor.toObjectInitializer();
+      CodeBuffer outputBuffer = getBuffer(outputUnit);
+
       int sizeBefore = outputBuffer.length;
       compiler.dumpInfoTask.registerElementAst(library, metadata);
       compiler.dumpInfoTask.registerElementAst(library, initializers);
@@ -1352,6 +1359,30 @@ class CodeEmitterTask extends CompilerTask {
     }
   }
 
+  void emitPrecompiledConstructor(String constructorName,
+                                  jsAst.Expression constructorAst) {
+    precompiledFunction.add(
+        new jsAst.FunctionDeclaration(
+            new jsAst.VariableDeclaration(constructorName), constructorAst));
+    precompiledFunction.add(
+   js.statement(r'''{
+          #.builtin$cls = #;
+          if (!"name" in #)
+              #.name = #;
+          $desc=$collectedClasses.#;
+          if ($desc instanceof Array) $desc = $desc[1];
+          #.prototype = $desc;
+        }''',
+        [   constructorName, js.string(constructorName),
+            constructorName,
+            constructorName, js.string(constructorName),
+            constructorName,
+            constructorName
+         ]));
+
+    precompiledConstructorNames.add(js('#', constructorName));
+  }
+
   String assembleProgram() {
     measure(() {
       invalidateCaches();
@@ -1360,7 +1391,7 @@ class CodeEmitterTask extends CompilerTask {
       // 'is$' method.
       typeTestEmitter.computeRequiredTypeChecks();
 
-      computeNeededClasses();
+      computeNeededDeclarations();
 
       mainBuffer.add(buildGeneratedBy());
       addComment(HOOKS_API_USAGE, mainBuffer);
@@ -1395,7 +1426,8 @@ class CodeEmitterTask extends CompilerTask {
       // Only output the classesCollector if we actually have any classes.
       if (!(nativeClasses.isEmpty &&
             compiler.codegenWorld.staticFunctionsNeedingGetter.isEmpty &&
-          outputClassLists.values.every((classList) => classList.isEmpty))) {
+          outputClassLists.values.every((classList) => classList.isEmpty) &&
+          typedefsNeededForReflection.isEmpty)) {
         // Shorten the code by using "$$" as temporary.
         classesCollector = r"$$";
         mainBuffer.add('var $classesCollector$_=$_{}$N$n');
@@ -1419,7 +1451,7 @@ class CodeEmitterTask extends CompilerTask {
       // Might create methodClosures.
       for (List<ClassElement> outputClassList in outputClassLists.values) {
         for (ClassElement element in outputClassList) {
-          generateClass(element, getElementDecriptor(element));
+          generateClass(element, getElementDescriptor(element));
         }
       }
 
@@ -1439,6 +1471,8 @@ class CodeEmitterTask extends CompilerTask {
           mainBuffer.write(';');
         }
 
+        // TODO(karlklose): document what kinds of fields this loop adds to the
+        // library class builder.
         for (Element element in elementDescriptors.keys) {
           // TODO(ahe): Should iterate over all libraries.  Otherwise, we will
           // not see libraries that only have fields.
@@ -1458,6 +1492,32 @@ class CodeEmitterTask extends CompilerTask {
           }
         }
 
+        // Emit all required typedef declarations into the main output unit.
+        // TODO(karlklose): unify required classes and typedefs to declarations
+        // and have builders for each kind.
+        for (TypedefElement typedef in typedefsNeededForReflection) {
+          OutputUnit mainUnit = compiler.deferredLoadTask.mainOutputUnit;
+          LibraryElement library = typedef.library;
+          // TODO(karlklose): add a TypedefBuilder and move this code there.
+          DartType type = typedef.alias;
+          int typeIndex = metadataEmitter.reifyType(type);
+          String typeReference =
+              encoding.encodeTypedefFieldDescriptor(typeIndex);
+          jsAst.Property descriptor = new jsAst.Property(
+              js.string(namer.classDescriptorProperty),
+              js.string(typeReference));
+          jsAst.Node declaration = new jsAst.ObjectInitializer([descriptor]);
+          String mangledName = namer.getNameX(typedef);
+          String reflectionName = getReflectionName(typedef, mangledName);
+          getElementDescriptorForOutputUnit(library, mainUnit)
+              ..addProperty(mangledName, declaration)
+              ..addProperty("+$reflectionName", js.string(''));
+          // Also emit a trivial constructor for CSP mode.
+          String constructorName = mangledName;
+          jsAst.Expression constructorAst = js('function() {}');
+          emitPrecompiledConstructor(constructorName, constructorAst);
+        }
+
         if (!mangledFieldNames.isEmpty) {
           var keys = mangledFieldNames.keys.toList();
           keys.sort();
@@ -1714,7 +1774,7 @@ class CodeEmitterTask extends CompilerTask {
         () => new ClassBuilder(element, namer));
   }
 
-  ClassBuilder getElementDecriptor(Element element) {
+  ClassBuilder getElementDescriptor(Element element) {
     Element owner = element.library;
     if (!element.isTopLevel && !element.isNative) {
       // For static (not top level) elements, record their code in a buffer