RFR: 8215708: ZGC: Add missing LoadBarrierNode::size_of()

[Erik Österlund]

Hi Per,

Looks good.

Thanks,
/Erik

On 2019-01-08 15:32, Per Liden wrote:
> LoadBarrierNode should implement size_of(). Otherwise cloning of such 
> nodes is broken since only part of the object will be copied. This 
> caused incorrect load barriers to be used in random places. For 
> example, we could generate a weak barrier instead of a strong barrier, 
> because the _weak member was not properly initialized when cloned.
>
> This patch also implements three other methods (cmp, adr_type and 
> match_edge) with an immediate call to ShouldNotReachHere(). This is a 
> pure safety net to catch any misuse of these. These should never be 
> called, but if they are called today we might not notice and instead 
> silently do the wrong thing.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8215708
> Webrev: http://cr.openjdk.java.net/~pliden/8215708/webrev.0
>
> Testing: tier{1,6,7}
>
> /Per