RFR: 8305880: Loom: Avoid putting stale object pointers in oops

[Stefan Karlsson]

On Wed, 12 Apr 2023 06:25:17 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> Generational ZGC has extra verification code for oops, which trigger asserts when it finds stale oops. We have cleaned away some usages of stale oops in the upstream repository (openjdk/jdk), but there are still a couple left in the Loom code. I propose that we rewrite the code, to pave the way for Generational ZGC.
> 
> I've tested this by running these patches on top of openjdk/fibers + ZGC. I've also tested this with Skynet + Generational ZGC, where these issues where first found.

Thanks for the reviews!

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PR Comment: https://git.openjdk.org/jdk/pull/13439#issuecomment-1515995129