[aarch64-port-dev ] RFR: Shenandoah import

[Aleksey Shipilev]

On 10/04/2017 02:36 PM, Roman Kennke wrote:
> Thanks for all the reviews so far.
> 
> In the meantime we've got two more changes that seem important to include. One is another
> improvement for Shenandoah isolation from Roland, and the other is a fix for a nasty deadlock (in
> Shenandoah) that only occurs in jdk8.
> 
> http://cr.openjdk.java.net/~rkennke/jdk8u-shenandoah-integration-2017-10-02/webrev.01/

+1 from me. Deadlock fix was tested multiple times already. LibraryCallKit change is tested briefly,
but should be evidently correct, and follows the usual suggestion for Shenandoah isolation. Complete
change against upstream looks like this:

-       Node* zlen_arg = load_array_length(z);
+       Node* zlen_arg = NULL;
+       if (UseShenandoahGC) {
+         Node *cast = new (C) CastPPNode(z, TypePtr::NOTNULL);
+         cast->init_req(0, control());
+         _gvn.set_type(cast, cast->bottom_type());
+         C->record_for_igvn(cast);
+         zlen_arg = load_array_length(cast);
+       } else {
+         zlen_arg = load_array_length(z);
+       }

-Aleksey