RFR: Factor out keep-alive barrier

[Roman Kennke]

Am 06.09.2017 um 16:35 schrieb Aleksey Shipilev:
> On 09/06/2017 03:58 PM, Roman Kennke wrote:
>> OK, I will put it back in. It will all change with the GC interface anyway...
>>
>>> *) ShenandoahSATBBarrier should be handled in
>>> ShenandoahBarrierSet::keep_alive_barrier?
> 
> Seems fine with me. ShenandoahSATBBarrier can be just renamed for this, right?
> 
> -Aleksey
> 

How about this:

http://cr.openjdk.java.net/~rkennke/keepalivebarrier/webrev.01/

?

Roman