Implement type argument access and reification of runtime types.

pkg/compiler/lib/src/js_backend/codegen/glue.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 code_generator_dependencies;
 
 import '../js_backend.dart';
 import '../../dart2jslib.dart';
 import '../../js_emitter/js_emitter.dart';
 import '../../js/js.dart' as js;
 import '../../constants/values.dart';
 import '../../elements/elements.dart';
 import '../../constants/expressions.dart';
+import '../../dart_types.dart' show TypeVariableType;
 
 /// Encapsulates the dependencies of the function-compiler to the compiler,
 /// backend and emitter.
 // TODO(sigurdm): Should be refactored when we have a better feeling for the
 // interface.
 class Glue {
   final Compiler _compiler;
 
   JavaScriptBackend get _backend => _compiler.backend;
 
@@ skipping 84 matching lines @@
 
 
   String getInterceptorName(Set<ClassElement> interceptedClasses) {
     return _backend.namer.nameForGetInterceptor(interceptedClasses);
   }
 
   js.Expression getInterceptorLibrary() {
     return new js.VariableUse(
         _backend.namer.globalObjectFor(_backend.interceptorsLibrary));
   }
+
+  FunctionElement getCreateRuntimeType() {
+    return _backend.getCreateRuntimeType();
+  }
+
+  FunctionElement getRuntimeTypeToString() {
+    return _backend.getRuntimeTypeToString();
+  }
+
+  FunctionElement getTypeArgumentWithSubstitution() {
+    return _backend.getGetRuntimeTypeArgument();
+  }
+
+  FunctionElement getTypeArgumentByIndex() {
+    return _backend.getGetTypeArgumentByIndex();
+  }
+
+  js.Expression getSubstitutionName(ClassElement cls) {
+    return js.string(_namer.substitutionName(cls));
+  }
+
+  int getTypeVariableIndex(TypeVariableType variable) {
+    return RuntimeTypes.getTypeVariableIndex(variable.element);
+  }
+
+  bool needsSubstitutionForTypeVariableAccess(ClassElement cls) {
+    ClassWorld classWorld = _compiler.world;
+    if (classWorld.isUsedAsMixin(cls)) return true;
+
+    Iterable<ClassElement> subclasses = _compiler.world.strictSubclassesOf(cls);
+    return subclasses.any((ClassElement subclass) {
+      return !_backend.rti.isTrivialSubstitution(subclass, cls);
+    });
+  }
 }