dart2js: store typeVariableReader stubs in the model.

pkg/compiler/lib/src/js_emitter/class_stub_generator.dart

Index: pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart b/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
index 01e745555f47d9618ac835f20cdda4cb918e010b..50f3fe3b97b66d548e74591d1227fa3ddd6b655f 100644
--- a/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
@@ -186,6 +186,51 @@ class ClassStubGenerator {
     }
     return new StubMethod(name, function);
   }
+
+  List<StubMethod> generateTypeVariableReaderStubs(ClassElement classElement) {

[floitsch, 2015/02/10 13:19:36]

An alternative location would be in the type_test_generator.

We could rename it to runtime_type_generator.dart.

[zarah, 2015/02/10 13:34:39]

Done.

+    List<StubMethod> stubs = <StubMethod>[];
+    List typeVariables = [];
+    ClassElement superclass = classElement;
+    while (superclass != null) {
+        for (TypeVariableType parameter in superclass.typeVariables) {
+          if (backend.emitter.readTypeVariables.contains(parameter.element)) {
+            stubs.add(

[zarah, 2015/02/10 12:50:30]

This method is copied from class_emitter. This line is different as well as the
return at the end of the method.

+                _generateTypeVariableReader(classElement, parameter.element));
+          }
+        }
+        superclass = superclass.superclass;
+      }
+
+    return stubs;
+  }
+
+  StubMethod _generateTypeVariableReader(ClassElement cls,
+                                         TypeVariableElement element) {
+    String name = namer.readTypeVariableName(element);
+    int index = RuntimeTypes.getTypeVariableIndex(element);
+    jsAst.Expression computeTypeVariable;
+
+    Substitution substitution =
+        backend.rti.computeSubstitution(
+            cls, element.typeDeclaration, alwaysGenerateFunction: true);
+    if (substitution != null) {
+      computeTypeVariable =
+          js(r'#.apply(null, this.$builtinTypeInfo)',
+             substitution.getCodeForVariable(index, backend.rti));
+    } else {
+      // TODO(ahe): These can be generated dynamically.
+      computeTypeVariable =
+          js(r'this.$builtinTypeInfo && this.$builtinTypeInfo[#]',
+              js.number(index));
+    }
+    jsAst.Expression convertRtiToRuntimeType = backend.emitter
+         .staticFunctionAccess(backend.findHelper('convertRtiToRuntimeType'));
+
+    return new StubMethod(name,

[zarah, 2015/02/10 12:50:30]

This method is copied from class_emitter. It differs from this line and below.

+                          js('function () { return #(#) }',
+                             [convertRtiToRuntimeType, computeTypeVariable]));
+  }
+
 }
 
 /// Creates two JavaScript functions: `tearOffGetter` and `tearOff`.