RFR: Verify marked objects

[Zhengyu Gu]

Good to me.

-Zhengyu

On 06/27/2017 08:27 AM, Aleksey Shipilev wrote:
> Our previous bug hunt identified a white spot in Verifier.
>
> Current Verifier only checks reachable objects, but there are objects that GC
> scans even though they are not reachable, because the marking data may be
> imprecise -- for example objects allocated past TAMS. This change adds the
> additional pass over marked objects to Verifier:
>   http://cr.openjdk.java.net/~shade/shenandoah/verifier-marked/webrev.01/
>
> It also moves the "After Partial" verification after the region recycling,
> because it would expectedly fail when scanning the "marked" objects in
> non-recycled CSet otherwise.
>
> Testing: hotspot_gc_shenandoah, specjbb
>
> Thanks,
> -Aleksey
>
>