RFR: 8277652: SIGSEGV in ShenandoahBarrierC2Support::verify_raw_mem for malformed control flow graph

[Roman Kennke]

On Tue, 23 Nov 2021 15:59:00 GMT, Jie Fu <jiefu at openjdk.org> wrote:

> Hi all,
> 
> `ShenandoahBarrierC2Support::verify_raw_mem` crashes due to `u->unique_ctrl_out()` [1] returns NULL for malformed control flow graph.
> It can be reproduced by running `compiler/vectorapi/TestIntrinsicBailOut.java` with `-XX:+UseShenandoahGC`.
> It would be better to fix it.
> 
> Thanks.
> Best regards,
> Jie
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp#L1925

Thank you, Jie!
I am currently working on a change that would make LRB runtime call not consume or produce raw memory at all, and would obsolete your change. See #6526 .

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PR: https://git.openjdk.java.net/jdk/pull/6525