RFR (XXS): 8026376: assert(false) failed: DEBUG MESSAGE: exception pc already set

[Vladimir Kozlov]

Don't read exception pc since it is not needed. You may trash a value in 
that register.

Thanks,
Vladimir

On 10/14/13 11:19 AM, Christian Thalinger wrote:
> https://bugs.openjdk.java.net/browse/JDK-8026376
> http://cr.openjdk.java.net/~twisti/8026376/webrev.00/
>
> 8026376: assert(false) failed: DEBUG MESSAGE: exception pc already set
> Reviewed-by:
>
> It made me suspicious that only the second assert fired (the exception pc check) and not the first one (the exception oop check). I checked all the places where JavaThread::exception_oop_offset() was used to clear the exception oop to see if we also clear the exception pc.
>
> In the deopt blob we have such a case. On x86 we clear both but on SPARC we don't.
>
> Added the missing null-store instruction makes the test case pass.
>
> Reading the exception pc is not really required but I've added it for completeness.
>