Generators return boxed values

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 1edf5ceb9d319b27c694afebee819fe436fdeecf..615367f1ff19368fc5c92e20bc931df3ca23a01d 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1385,6 +1385,33 @@ void Genesis::InitializeExperimentalGlobal() {
         *generator_object_prototype);
     native_context()->set_generator_object_prototype_map(
         *generator_object_prototype_map);
+
+    // Create a map for iterator result objects.
+    ASSERT(object_map->inobject_properties() == 0);
+    STATIC_ASSERT(JSGeneratorObject::kResultPropertyCount == 2);
+    Handle<Map> iterator_result_map = factory()->CopyMap(object_map, 2);
+    ASSERT(iterator_result_map->inobject_properties() == 2);
+
+    Handle<DescriptorArray> descriptors = factory()->NewDescriptorArray(0, 2);
+    DescriptorArray::WhitenessWitness witness(*descriptors);
+    iterator_result_map->set_instance_descriptors(*descriptors);
+
+    STATIC_ASSERT(JSGeneratorObject::kResultValuePropertyIndex == 0);

[Michael Starzinger, 2013/05/06 11:22:32]

Is there a particular reason why cannot use the index constant in the calls
below instead of using static-asserts and hard-coded constants? Same applies for
the second index below and the count above.

+    Handle<String> value_string = factory()->InternalizeOneByteString(
+        STATIC_ASCII_VECTOR("value"));
+    FieldDescriptor value_descriptor(*value_string, 0, NONE,
+                                     Representation::Tagged());
+    iterator_result_map->AppendDescriptor(&value_descriptor, witness);
+
+    STATIC_ASSERT(JSGeneratorObject::kResultDonePropertyIndex == 1);
+    Handle<String> done_string = factory()->InternalizeOneByteString(
+        STATIC_ASCII_VECTOR("done"));
+    FieldDescriptor done_descriptor(*done_string, 1, NONE,
+                                    Representation::Tagged());
+    iterator_result_map->AppendDescriptor(&done_descriptor, witness);
+
+    iterator_result_map->set_unused_property_fields(0);
+    native_context()->set_iterator_result_map(*iterator_result_map);
   }
 }