Calling a generator function returns a generator object

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 76f0a3c9a86e052add7782f4600217d317fc5a44..826d241e74ea636ca38ad5a7e21fb519a8b0c286 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -4089,9 +4089,8 @@ MaybeObject* Heap::AllocateInitialMap(JSFunction* fun) {
   int instance_size;
   int in_object_properties;
   if (fun->shared()->is_generator()) {
-    // TODO(wingo): Replace with JS_GENERATOR_OBJECT_TYPE.
-    instance_type = JS_OBJECT_TYPE;
-    instance_size = JSObject::kHeaderSize;
+    instance_type = JS_GENERATOR_OBJECT_TYPE;
+    instance_size = JSGeneratorObject::kSize;
     in_object_properties = 0;
   } else {
     instance_type = JS_OBJECT_TYPE;
@@ -4340,6 +4339,22 @@ MaybeObject* Heap::AllocateJSObjectWithAllocationSite(JSFunction* constructor,
 }
 
 
+MaybeObject* Heap::AllocateJSGeneratorObject(JSFunction *function) {
+  ASSERT(function->shared()->is_generator());
+  Map *map;
+  if (function->has_initial_map()) {
+    map = function->initial_map();
+  } else {
+    // Allocate the initial map if absent.
+    MaybeObject* maybe_map = AllocateInitialMap(function);
+    if (!maybe_map->To(&map)) return maybe_map;
+    function->set_initial_map(map);
+  }
+  ASSERT(map->instance_type() == JS_GENERATOR_OBJECT_TYPE);
+  return AllocateJSObjectFromMap(map);
+}
+
+
 MaybeObject* Heap::AllocateJSModule(Context* context, ScopeInfo* scope_info) {
   // Allocate a fresh map. Modules do not have a prototype.
   Map* map;