RFR: 8305896: Alternative full GC forwarding [v12]

[Roman Kennke]

On Thu, 4 May 2023 10:57:07 GMT, Erik Österlund <eosterlund at openjdk.org> wrote:

>> Ok that is great stuff! Maybe it'd be useful to move it to a central place with this PR (alternative full GC fwding), because we're going to need it for other purposes, too (other GC tables, i-hash, faster type checking, maybe more?)
>> 
>> Oh and that code is using __int128 type, how/where do I get that outside of GCC?
>
> Yes - great idea. Maybe somewhere in utilities. We might swap to it with ZGC as well when things settle down there.

Ok, I pushed a change that uses @rose00's better hashing. I added/changed the 128-bit multiplication to (hopefully) make it portable. Let's see what GHA has to say about this ;-)

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PR Review Comment: https://git.openjdk.org/jdk/pull/13582#discussion_r1184882541