[esnext] Fix various callsites to use is_resumable, not is_generator

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 39badb69362c7c68c50287dfd61a1854acf28b84..43d9c684a2bb4f168f3004fa78a2550d7090de80 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1298,6 +1298,9 @@ Handle<JSFunction> Factory::NewFunction(Handle<String> name, Handle<Code> code,
   ElementsKind elements_kind =
       type == JS_ARRAY_TYPE ? FAST_SMI_ELEMENTS : FAST_HOLEY_SMI_ELEMENTS;
   Handle<Map> initial_map = NewMap(type, instance_size, elements_kind);
+  // TODO(littledan): Why do we have this is_generator test when
+  // NewFunctionPrototype already handles finding an appropriately
+  // shared prototype?
   if (!function->shared()->is_generator()) {
     if (prototype->IsTheHole()) {
       prototype = NewFunctionPrototype(function);
@@ -1327,9 +1330,9 @@ Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
   // can be from a different context.
   Handle<Context> native_context(function->context()->native_context());
   Handle<Map> new_map;
-  if (function->shared()->is_generator()) {
-    // Generator prototypes can share maps since they don't have "constructor"
-    // properties.
+  if (function->shared()->is_resumable()) {

[caitp (gmail), 2016/05/20 13:35:56]

Based on how generator_object_prototype_map is created, this doesn't look
correct to me

```
  Handle<JSFunction> object_function(native_context()->object_function());
  Handle<Map> generator_object_prototype_map = Map::Create(isolate(), 0);
  Map::SetPrototype(generator_object_prototype_map, generator_object_prototype);
  native_context()->set_generator_object_prototype_map(
      *generator_object_prototype_map);
```

But I don't think this code gets reached without adding an API for creating
async functions, so I don't believe this can be verified yet

[Dan Ehrenberg, 2016/05/20 14:59:19]

Oh you're right, oops. The new patch asserts that we never get here for async
functions.

+    // Generator and async function prototypes can share maps since they don't
+    // have "constructor" properties.
     new_map = handle(native_context->generator_object_prototype_map());
   } else {
     // Each function prototype gets a fresh map to avoid unwanted sharing of
@@ -1342,7 +1345,7 @@ Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
   DCHECK(!new_map->is_prototype_map());
   Handle<JSObject> prototype = NewJSObjectFromMap(new_map);
 
-  if (!function->shared()->is_generator()) {
+  if (!function->shared()->is_resumable()) {
     JSObject::AddProperty(prototype, constructor_string(), function, DONT_ENUM);
   }
 
@@ -1676,7 +1679,7 @@ void Factory::NewJSArrayStorage(Handle<JSArray> array,
 
 Handle<JSGeneratorObject> Factory::NewJSGeneratorObject(
     Handle<JSFunction> function) {
-  DCHECK(function->shared()->is_resumable());
+  DCHECK(function->shared()->is_generator());
   JSFunction::EnsureHasInitialMap(function);
   Handle<Map> map(function->initial_map());
   DCHECK_EQ(JS_GENERATOR_OBJECT_TYPE, map->instance_type());