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

[Chad Rakoczy]

On Fri, 30 May 2025 23:21:41 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> I have created a RFE to move the immutable data from the nmethod to a separate class. [JDK-8358213](https://bugs.openjdk.org/browse/JDK-8358213)
>
> Thanks.  Let's keep current changes as it is with small comment:
>  IMMUTABLE_DATA_REFERENCES is used with `sizeof()` in all places - consider using instead 
>  ```
>  #define IMMUTABLE_DATA_REFERENCES_SIZE sizeof(int)
>  ```

I updated it to hold the size based on @vnkozlov suggestion ([source](https://github.com/chadrako/jdk/blob/b0dad6659047553ebee1387939e54ea817b31cb1/src/hotspot/share/code/nmethod.hpp#L172))

@dean-long Are you good with this change and moving the immutable data to a separate class in a seperate issue ([JDK-8358213](https://bugs.openjdk.org/browse/JDK-8358213))?

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PR Review Comment: https://git.openjdk.org/jdk/pull/23573#discussion_r2122223999