RFR (XS): JDK-6563994 - assert(wf.check_method_context(ctxk, m), "proper context") failed

[Vladimir Kozlov]

Good.

Vladimir

On 5/19/14 8:42 AM, S. Bharadwaj Yadavalli wrote:
> I would like to get reviews for a small fix for the occasional nightly failures reported in
> https://bugs.openjdk.java.net/browse/JDK-6563994
>
> The assertion is observed to be triggered while looking up for a monomorphic call target. It happens in a rare
> situation, where the method holder class is redefined at safepoints *after* resolution of the target method's class (in
> find_monomorphic_target() - src/share/vm/ci/ciMethod.cpp:694) but *before* the call of find_unique_concrete_method() -
> src/share/vm/ci/ciMethod.cpp:733). This change returns NULL for a such a redefined method which would be marked as old,
> indicating that candidate call target may not be inlined, since all we have is a pointer to an old method that has been
> redefined. The subsequent assertion of check_method_context for old methods is not applicable and hence not done for
> such methods.
>
> Testing:
>
> Without the fix: Was able to trigger the assertion upon running the test nsk.jvmti.RetransformClasses.retransform001 a
> few hundred times.
>
> With the fix: Was able to run the test for over 3000 iterations continuously for more than 3 days without triggering the
> assertion.
>
> Ran JPRT tests successfully
>
> webrev: http://cr.openjdk.java.net/~bharadwaj/6563994/webrev_0/
> bug: https://bugs.openjdk.java.net/browse/JDK-6563994
>
> Thanks,
>
> Bharadwaj