RFR: 8256011: Shenandoah: Don't resurrect finalizably reachable objects [v2]

[Zhengyu Gu]

On Sun, 8 Nov 2020 10:03:07 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> In the weak-LRB we currently return referents when it is 'marked', that is when it's either reachable strongly or through a finalizable object. This means a finalizable object can be resurrected by Reference.get(), which is wrong. Only truly strongly reachable objects should be returned by Reference.get() during weak-reference-processing. 
>> 
>> Testing: hotspot_gc_shenandoah, tier1 & tier2 with -XX:+UseShenandoahGC
>
> Roman Kennke has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Simplify condition, don't resurrect finalizably reachable objects even on phantom access

Looks good.

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Marked as reviewed by zgu (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1109