RFR: Fix Shenandoah build on ppc64

[Aleksey Shipilev]

On 08/23/2018 05:46 AM, Andrew Hughes wrote:
> Bug: https://icedtea.classpath.org/bugzilla/show_bug.cgi?id=3620
> Webrev: http://cr.openjdk.java.net/~andrew/shenandoah-8/pr3620/

Yes.

> A simple fix is needed to get Shenandoah building on ppc64{be,le}.
> That port is missing an implementation of shenandoahBarrierSet, as
> provided for aarch64, sparc, zero & x86:

Right. We actually have stubs for PPC in sh/jdk10:
  http://hg.openjdk.java.net/shenandoah/jdk10/rev/7a84366f5de1

...but I thought PPC support was not needed in 8u, since PPC port got integrated into 9.

I pushed your change to sh/jdk8:
  http://hg.openjdk.java.net/shenandoah/jdk8u/hotspot/rev/fd67793f57f6

You can cherry-pick it up to aarch64-port/shenandoah-8u, or wait for bulk integration.

Thanks,
-Aleksey