RFR: Make sure selective barriers enabling/disabling works

[Roman Kennke]

Am 23.11.2017 um 09:30 schrieb Aleksey Shipilev:
> On 11/22/2017 09:17 PM, Aleksey Shipilev wrote:
>> http://cr.openjdk.java.net/~shade/shenandoah/barrier-disable-asserts/webrev.01/
>>
>> This adds asserts and fixes up some of the barrier selection flags to make sure they work correctly.
>> All asserts are validated with new test that walks through interpreter, C1 and C2 with all
>> combinations of barrier flags. (It takes a while, around 400s for the test in fastdebug mode). This
>> code would be more interesting in sh/jdk8u, which lacks some of the flag guards.
>>
>> This allows us to make sure our performance experiments around barriers are correct, as well as
>> check that "passive" mode indeed has no barriers enabled.
>>
>> Testing: hotspot_gc_shenandoah {fastdebug|release}
> 
> Added a few checks for ShenandoahCloneBarrier in barrier set slowpaths:
>    http://cr.openjdk.java.net/~shade/shenandoah/barrier-disable-asserts/webrev.02/
> 
> -Aleksey
> 
> 

Looks good.

Roman