RFR: Bulk integration from jdk/jdk 2018-04-23

[Aleksey Shipilev]

On 04/23/2018 06:48 PM, Roman Kennke wrote:
> This merges latest upstream changes, based on:
> 
> changeset:   50053:69d7398038c5
> user:        rehn
> date:        Wed Apr 18 09:25:51 2018 +0200
> summary:     8195099: Concurrent safe-memory-reclamation mechanism
> 
> It brings lots of goodies, the top 3 being:
> 
> - thread local GC data (replacing our gcstate, satb queue and
> oom_during_evac, possibly in the future the gclab)
> - runtime object equals barriers
> - interpreter/assembler GC code generator
> 
> The complete list of changes:
> http://cr.openjdk.java.net/~rkennke/merge-2018-04-23/changesets
> 
> Diff of Shenandoah changes:
> http://cr.openjdk.java.net/~rkennke/merge-2018-04-23/shenandoah-changes.patch

Looks good. We better push this soon to see how it holds water. Ugh, I expect so many weird issues
from this, and it moves Shenandoah code apart from backports. But, there is nothing we can do.

I have only one question: what is CompressedOops::is_null and friends? Is is a newfangled way to
deal with compressed oops? Does it work on non-coops paths?

Thanks,
-Aleksey