[aarch64-port-dev ] [8u-aarch64] RFR/RFC 8186325: AArch64: jtreg test hotspot/test/gc/g1/TestJNIWeakG1/TestJNIWeakG1.java SEGV

[Aleksey Shipilev]

Recent backport of JNI Weak handling in G1:
  https://bugs.openjdk.java.net/browse/JDK-8176100

...brought the problem, which we detected when doing Shenandoah testing. We have the
gc/shenandoah/jni/TestJNIGlobalRefs.sh test that breaks on AArch64 with the attempted fix of JNI
Weak there:
  https://mail.openjdk.java.net/pipermail/shenandoah-dev/2019-May/009770.html

The trouble is already fixed in 10+:
  https://bugs.openjdk.java.net/browse/JDK-8186325
  https://hg.openjdk.java.net/jdk10/jdk10/hotspot/rev/3a8e8737cb36

...and we need to backport it. The fix is aarch64-specific, and so does not apply to 8u upstream.
This is not Shenandoah-specific failure: G1 should fail the same way, but only Shenandoah tests
capture it. The fix does not apply cleanly, because there are Shenandoah changes nearby.

Webrev for aarch64-port/jdk8u-shenandoah/hotspot:
  https://cr.openjdk.java.net/~shade/8186325/webrev.8u-aarch64.01/

Testing: hotspot_gc_shenandoah on aarch64 (used to fail, now it passes)

-- 
Thanks,
-Aleksey