RFR (S): 8191567: Refactor ciInstanceKlass G1 keep alive barrier to use Access API.

[David Holmes]

Hi Erik,

Does "phantom" here have any relationship to PhantomReference?

Meta-question on access API: if

RootAccess<IN_CONCURRENT_ROOT | ON_PHANTOM_OOP_REF>::oop_load(addr);

keeps the value alive, what can cause the value to be allowed to go dead 
again?

Thanks,
David

On 25/11/2017 2:22 AM, Erik Österlund wrote:
> Hi,
> 
> When creating a ciInstanceKlass handle, G1 might need a SATB barrier to 
> keep "peeked" weak klass pointers alive during marking.
> This should now be done with the Access API instead of manual calls to 
> the G1 SATB barrier.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8191567
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8191567/webrev.00/
> 
> Thanks,
> /Erik