RFR: 8276927: [PPC64] Port shenandoahgc to linux on ppc64le

[Martin Doerr]

On Thu, 11 Nov 2021 11:32:49 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Port the Shenandoah garbage collector (JDK-8241457)[https://bugs.openjdk.java.net/browse/JDK-8241457] to linux on ppc64le.
>
> src/hotspot/cpu/ppc/gc/shenandoah/c1/shenandoahBarrierSetC1_ppc.cpp line 83:
> 
>> 81:     LIRGenerator* gen = access.gen();
>> 82: 
>> 83:     if (ShenandoahCASBarrier) {
> 
> I am not sure, but I almost think we should not even end up in the method with -ShenandoahCASBarrier. If anything, -ShenandoahCASBarrier should result in only calling super to emit regular CAS without any barriers.

We hit this case when running `jdk/bin/java -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive -version`. x86 and aarch64 check for ShenandoahCASBarrier, too. So, looks like these checks are needed and correct.

-------------

PR: https://git.openjdk.java.net/jdk/pull/6325