RFR: 8349088: De-virtualize Codeblob and nmethod [v2]

[Vladimir Kozlov]

On Sun, 9 Feb 2025 19:43:29 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Remove virtual methods from CodeBlob and nmethod to simplify saving/restoring in Leyden AOT cache. It avoids the need to patch hidden VPTR pointer to class's virtual table.
>> 
>> Added C++ static asserts to make sure no virtual methods are added in a future.
>> 
>> Fixed/cleaned SA code which process CodeBlob and its subclasses. Use `CodeBlob::_kind` field value to determine the type of blob.
>> 
>> Tested tier1-5, hs-tier6-rt (for JFR testing), stress, xcomp
>
> Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix Zero and Minimal VM builds

I adopted Stefan's suggestion. I agree that it is more "future-proof".

I also remove underscore `_` from `CodeBlobKind` names.

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PR Comment: https://git.openjdk.org/jdk/pull/23533#issuecomment-2652333587
PR Comment: https://git.openjdk.org/jdk/pull/23533#issuecomment-2652335723