RFR(sh/jdk8): [backport] 8228369: Shenandoah: Refactor LRB C1 stubs

[Roman Kennke]

It turns out that the aarch64 parts have been incorrect. Please review 
this webrev instead:

http://cr.openjdk.java.net/~rkennke/JDK-8228369-jdk8/webrev.01/

Testing: hotspot_gc_shenandoah, specjvm, both on x86 and aarch64, also 
with upcoming SFX barriers change.

Ok?

Thanks,
Roman

On 23/11/2020 20:25, Roman Kennke wrote:
> This backports the following issue to jdk8:
> 
> https://bugs.openjdk.java.net/browse/JDK-8228369
> 
> This is in preparation for the SFX barrier backport.
> 
> Due to missing GC interfaces, I had to put some code in c1_Runtime*, it 
> is following the same pattern as other GC runtime stubs.
> 
> http://cr.openjdk.java.net/~rkennke/JDK-8228369-jdk8/webrev.00/
> 
> Let's also include a follow-ups:
> 
> https://bugs.openjdk.java.net/browse/JDK-8229709
> http://cr.openjdk.java.net/~rkennke/JDK-8229709-jdk8/webrev.00/
> 
> The other two follow-ups ( JDK-8229470 and JDK-8229977) don't apply to 
> jdk8 because of different implementations.
> 
> Can I please get a review?
> 
> Thanks,
> Roman