RFR: Bulk backports to sh/jdk11 2020-04-20

[Zhengyu Gu]

No JDK-8237396?

-Zhengyu

On 4/20/20 9:10 AM, Roman Kennke wrote:
> This backports the following changes from jdk/jdk:
> 
>    8242316: Shenandoah: Turn NULL-check into assert in SATB slow-path entry
>    8242301: Shenandoah: Inline LRB runtime call
>    8242273: Shenandoah: accept either SATB or IU barriers, but not both
>    8242271: Shenandoah: add test to verify GC mode unlock
>    8242054: Shenandoah: New incremental-update mode
>    8242217: Shenandoah: Enable GC mode to be diagnostic/experimental and
> have a name
>    8242130: Shenandoah: Simplify arraycopy-barrier dispatching
>    8241700: Shenandoah: Fold ShenandoahKeepAliveBarrier flag into
> ShenandoahSATBBarrier
>    8241675: Shenandoah: assert(n->outcnt() > 0) at
> shenandoahSupport.cpp:2858 with
> java/util/Collections/FindSubList.java
> 
> 
> http://cr.openjdk.java.net/~rkennke/backport-shjdk11-2020-04-20/webrev.00/
> 
> Testing: hotspot_gc_shenandoah
> 
> Ok?
> 
> Roman
>