869735 - Fixes to ParallelArray compilation to support generational GC

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Terrence Cole [:terrence]]

Attachment: v0

This includes 3 fixes: the first two hunks ensure that two allocation sites that flow into CompilerRoots are correctly tenured. The third hunk is to keep us from accessing the arena header of arbitrary objects that flow into parallel code: nursery things have no arena header.

Comment 1

[Niko Matsakis [:nmatsakis]]

Comment on attachment 746696 [details] [diff] [review]
v0

Review of attachment 746696 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/builtin/ParallelArray.cpp
@@ -115,5 @@
>  /*static*/ JSObject *
>  ParallelArrayObject::newInstance(JSContext *cx)
>  {
>      gc::AllocKind kind = gc::GetGCObjectKind(NumFixedSlots);
> -    RootedObject result(cx, NewBuiltinClassInstance(cx, &class_, kind));

Actually I had a comment about this change: I believe this will cause *all* parallel arrays to be pre-tenured, which doesn't seem like the right thing to do. I imagine we should pass in the Tenured state to newInstance() as a parameter.

Comment 2

[Terrence Cole [:terrence]]

Green try at:
https://tbpl.mozilla.org/?tree=Try&rev=ab2edeb50f5f

Pushed at:
https://hg.mozilla.org/integration/mozilla-inbound/rev/c61c7b28bace

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

https://hg.mozilla.org/mozilla-central/rev/c61c7b28bace