Introduce extras export object.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 55b5b3141e1b723f72ce1c5fad5c7ebfd1b38b62..c86e7aa6ae53e78dacf20ad5404540868065387e 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1467,7 +1467,7 @@ bool Genesis::CompileExtraBuiltin(Isolate* isolate, int index) {
   Handle<String> source_code =
       isolate->bootstrapper()->SourceLookup<ExtraNatives>(index);
   Handle<Object> global = isolate->global_object();
-  Handle<Object> exports = isolate->builtin_exports_object();
+  Handle<Object> exports = isolate->extras_exports_object();
   Handle<Object> args[] = {global, exports};
   return CompileNative(isolate, name, source_code, arraysize(args), args);

[domenic, 2015/05/18 17:41:39]

I think removing the access to the buildin_exports_object prevents extras code
from using InternalPackedArray.

[Yang, 2015/05/18 18:30:55]

This is correct and intentional. I want to have 
- a "shared" container for all normal natives that are included in the snapshot.
After running the internal scripts, this container will be thrown away.
- a "builtin exports" container to export and keep stuff required for
experimental natives, since those are not part of the snapshot, and need to stay
alive after creating the snapshot.
- a "extras exports" container for sharing things between C++ and JS for extra
scripts
- an "api exports" container to export things from normal natives to extra
natives, for example InternalPackedArrays.

The latter is not implemented yet, and I'm not entirely sure whether extra
exports and api exports should be the same object. It would be simpler if they
are, but the api exports can die after the extra scripts have been executed,
where as the extra exports need to stay alive for its purpose.

 }
@@ -1918,12 +1918,19 @@ bool Genesis::InstallNatives() {
       factory()->NewJSObject(isolate()->object_function());
   JSObject::NormalizeProperties(shared, CLEAR_INOBJECT_PROPERTIES, 16,
                                 "container to share between native scripts");
+
   Handle<JSObject> builtin_exports =
       factory()->NewJSObject(isolate()->object_function());
   JSObject::NormalizeProperties(builtin_exports, CLEAR_INOBJECT_PROPERTIES, 16,
                                 "container to export to experimental natives");
   native_context()->set_builtin_exports_object(*builtin_exports);
 
+  Handle<JSObject> extras_exports =
+      factory()->NewJSObject(isolate()->object_function());
+  JSObject::NormalizeProperties(builtin_exports, CLEAR_INOBJECT_PROPERTIES, 2,

[domenic, 2015/05/18 16:43:11]

copypasta: builtin_exports should be extras_exports

[Yang, 2015/05/18 18:30:56]

Yup. Thanks for catching this. Will fix.

+                                "container to export to extra natives");
+  native_context()->set_extras_exports_object(*extras_exports);
+
   if (FLAG_expose_natives_as != NULL) {
     Handle<String> shared_key = factory()->NewStringFromAsciiChecked("shared");
     JSObject::AddProperty(builtins, shared_key, shared, NONE);