[aarch64-port-dev ] jdk8: random null pointer exceptions from javac

[Andrew Dinn]

On 05/11/15 10:56, Edward Nevill wrote:
> On Thu, 2015-11-05 at 09:25 +0000, Andrew Dinn wrote:
>> On 04/11/15 17:18, Edward Nevill wrote:
>> 
> . . .
>> 
>> Is there a disparity in the GC behaviour which means this works on
>> jdk9?
> 
> Yes. Its a different GC. I only observe the problem with ParallelGC.
> This does not mean that the problem is not there with G1GG, it is a
> random, infrequent bug so it may be sitting there waiting with G1GC.

Ok, that is all clear now.

So, your patch purports to fix a symptom rather than resolve the root
(oh, please!) cause. i.e. that the GC fails to scan oops saved in the
frame pointer register.

Much as the fix is nice to have adopting it makes it unlikely that we
will find out whether (and if so, why) the GC is broken. I'd very much
like to have this fix now. So perhaps we need to commit it and also
raise the rfp oop checking issue with gc devs in order to see whether we
can revert to using rfp for oop spills at some later date.

regards,


Andrew Dinn
-----------