RFR(S) 8224978: Shenandoah: Allows root verifier to verify some roots outside safepoints with proper locks

[Aleksey Shipilev]

On 5/29/19 6:01 PM, Zhengyu Gu wrote:
> Please review this patch that allows root verifier to verify CLDG and code roots outside safepoints,
> with proper locks.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8224978
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8224978/webrev.00/

*) Don't we want to demote those checks to "asserts"? Is there a reason to have these checks in
release bits (and make it pay on tiny root sets)?

*) Maybe it should be moved to shenandoahAsserts. I think these new definitions:

 shenandoah_assert_safepoint()
 shenandoah_assert_locked_or_safepoint(lock)

-Aleksey