RFR: Fix ExtendedDTraceProbes with Shenandoah

[Zhengyu Gu]

On 09/19/2018 11:17 AM, Roland Westrelin wrote:
> 
>> http://cr.openjdk.java.net/~zgu/shenandoah/extended_dtrace_probes/webrev.00/
> 
> Can you give some more details? What destroys the base? Is this a
> ExtendedDTraceProbes fix?

This is an attempt to fix C1 crash with ExtendedDTraceProbes.

we are not sure about it is right fix (offline chat discussion).  This 
patch might just kill the symptom that described in attached "before fix 
LIR", since G1 generates similar LIR, but happens to use different 
register for loading 0x10 @146, so it does not destroy base.

Unfortunately, it is not the case for Shenandoah, load @146 destroys the 
base ... could it be register allocator's bug?

Thanks,

-Zhengyu


> 
> Roland.
>