RFR: 8205923: ZGC: Verification applies load barriers before verification

[Per Liden]

Looks good!

/Per

On 2018-06-27 15:15, Stefan Karlsson wrote:
> Hi all,
> 
> Please review this patch to stop applying load barriers in the Mark End 
> verification.
> 
> http://cr.openjdk.java.net/~stefank/8205923/webrev.01/
> https://bugs.openjdk.java.net/browse/JDK-8205923
> 
> The recent IN_CONCURRENT_ROOT changes introduced load barriers to our 
> Mark End verification. These load barriers are unnecessary because all 
> roots should have been fixed at that point.
> 
> The object oop field verification applied a load barrier to be able to 
> load stale j.l.Reference::referents, and as an effect applied load 
> barriers to all fields. This patch skips visiting the referents and uses 
> RawAccess loads for all other fields.
> 
> This patch builds upon the JDK-8205922, which introduces the mechanism 
> to skip visiting referents in oop_iterate calls.
> 
> Thanks,
> StefanK