RFR(sh/jdk8): [backport] 8232992: Shenandoah: Implement self-fixing interpreter LRB

[Aleksey Shipilev]

On 11/26/20 9:00 PM, Roman Kennke wrote:
> This backports the issue:
> https://bugs.openjdk.java.net/browse/JDK-8257180

More like
   https://bugs.openjdk.java.net/browse/JDK-8232992

> http://cr.openjdk.java.net/~rkennke/JDK-8232992-jdk8/webrev.01/

*) src/cpu/x86/vm/macroAssembler_x86.cpp

Why do you need these?

5790   Register result_dst = dst;

5810   Register result_dst = dst;

*) src/cpu/x86/vm/shenandoahBarrierSetAssembler_x86.cpp

save/restore_xmm_registers are cherry-picked from some other changeset? I ask because it would break 
x86_32 without UseSSE=2 (which I am fixing upstream now, and would backport). It is important to 
record that we backported this change, so that we known it affects 8-shenandoah after this lands.

Otherwise looks fine.

-- 
Thanks,
-Aleksey