RFR: 8316694: Implement relocation of nmethod within CodeCache [v3]

[Vladimir Kozlov]

On Fri, 30 May 2025 00:50:31 GMT, Dean Long <dlong at openjdk.org> wrote:

>> The more I look on it the more I like Dean's idea. I am withdrawing my previous objection.
>> Let's have a  **NOT virtual** class similar to CodeBlob.
>> Consider moving associated `*_offset` fields from `nmethod` to new class.
>
> @vnkozlov , when I first proposed this [1], you had a concern about Leyden.  Is it still a concern?
> [1] https://github.com/openjdk/jdk/pull/21276#discussion_r1853211488

I still have that concern for **mutable**  data which includes relocations which accessed frequently.

I don't think accessing **immutable** is performance critical. They mostly accessed during deoptimization and from JVMTI.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23573#discussion_r2114974264