[aarch64-port-dev ] RFR: 8209413: AArch64: NPE in clhsdb jstack command

[Andrew Haley]

On 2/18/19 7:36 AM, Nick Gasson (Arm Technology China) wrote:
> http://cr.openjdk.java.net/~ngasson/8209413/webrev.03/
> 
> It contains your suggested change below, as well as an extra check in 
> the AARCH64Frame two-argument constructor that the PC from SP[-1] is 
> valid. Also changed SharedRuntime::generate_native_wrapper and 
> TemplateInterpreterGenerator::generate_native_entry to save an accurate 
> return PC in the frame anchor.

That looks right, thanks. OK.

> There's a FIXME in set_last_Java_frame like this:
> 
>    } else {
>      // FIXME: This is almost never correct.  We should delete all
>      // cases of set_last_Java_frame with last_java_pc=NULL and use the
>      // correct return address instead.
>      adr(scratch, pc());
>    }
> 
> Should we do this now? There's only two places I can see: 
> StubGenerator::generate_throw_exception and the set_last_Java_frame 
> overload that takes a Label.

I hate cruft like this, but it's not actually a bug, and any change in this
delicate area has a non-zero probability of breaking something. On the other
hand, it would be a very low-risk change.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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