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

[Per Liden]

Thanks Nils!

/Per

On 01/08/2019 06:04 PM, Nils Eliasson wrote:
> Looks good!
> 
> // Nils
> 
> 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