RFR(XXS): 8165018: Missing memory barrier for PPC64 in Unsafe_GetObjectVolatile

[Doerr, Martin]

Hi,

we found that a memory barrier for PPC64 is missing in the current Unsafe implementation. get_volatile already contains the memory barrier for "support_IRIW_for_not_multiple_copy_atomic_cpu". The same is needed in Unsafe_GetObjectVolatile.

Here's my webrev:
http://cr.openjdk.java.net/~mdoerr/8165018_UnsafePPC64/webrev.00/

And while looking at it I wonder why Unsafe_GetObjectVolatile does not contain a G1 barrier like Unsafe_GetObject. Is it not possible to use the Volatile version to access the referent field of a Reference?

Please review. As it is shared code, I will need a sponsor, please.

Best regards,
Martin