RFR: JDK-8221766: Load-reference barriers for Shenandoah

[Roman Kennke]

>> - we need enter()/leave() around the barrier because this is now called in some places that don't
>> have a proper frame, yet.
> 
> Is it better to put enter/leave we actually call LRB from?

Naaa, this would be too cumbersome and introduce stuff into shared code 
that is only related to the actual LRB.

Roman


> I don't know the full implications of
> this, though.
> 
>> Incremental:
>> http://cr.openjdk.java.net/~rkennke/JDK-8221766/webrev.02.diff/
>> Full:
>> http://cr.openjdk.java.net/~rkennke/JDK-8221766/webrev.02/
> 
> Looks okay to me. Andrew needs to take a look at aarch64 code. This patch fixes AArch64 problems for me.
> 
> -Aleksey
>