SIGSEGV in C2 Node::unique_ctrl_out on 11.0.4

[Vitaly Davidovich]

On Thu, Sep 19, 2019 at 8:04 AM Roland Westrelin <rwestrel at redhat.com>
wrote:

>
> > So assuming I have one, how would I go about using it? Try running the
> > program and specify the replay file to be used to replay compilations? I
> > know you guys introduced this thing a while back, but I’ve never actually
> > used it :).
>
> Replay compilation only replays the compilation and is run with:
>
> java <same vm options the crashing vm had> -cp .... -XX:+ReplayCompiles
> -XX:ReplayDataFile=replay_pidxxx.log -XX:+ReplayIgnoreInitErrors
>
> Assuming the classpath is set correctly and there's no generated methods
> that c2 can't find in the classpath (from lambdas for instance), the
> crash should reproduce.
>
> Roland.

Thanks Roland! I’ll see if I can make some progress on this.

I briefly examined the disassembly and register info from the coredump and
am reasonably certain it’s the `this` ptr that’s null (ie we’re calling
unique_ctrl_out on a NULL Node).  That’s not super useful to figure out the
root issue, of course.

It also looks like it’s compiling some Scala generated bytecode (ie scalac
output).  Perhaps it’s producing something peculiar, not seen with Java
compilers.

>
> --
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