[foreign-memaccess+abi] RFR: 8317324: Add an overload to bind a memory segment var handle at an offset

[Jorn Vernee]

On Fri, 29 Sep 2023 16:09:24 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> This PR adds an overload which binds a memory segment var handle offset coordinate to a provided constant value.
> 
> This is useful when the client knows that the accessed offset will be e.g. zero, or some other known constant value, thus reducing the number of coordinates that var handles clients will have to provide on each access.

Do we need an overload for `ValueLayout::varHandle` as well? That method allows accessing the var handle cache on a ValueLayout, but the overload would always have to create a new VarHandle with the bound coordinate (unless we want a specialized cache for `0` offset maybe...). So, I don't think having on overload there is super important.

-------------

Marked as reviewed by jvernee (Committer).

PR Review: https://git.openjdk.org/panama-foreign/pull/900#pullrequestreview-1651122276