RFR: 8349088: De-virtualize Codeblob and nmethod [v9]

[Vladimir Kozlov]

On Sat, 15 Feb 2025 06:13:57 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:
> 
>   Address comments

I removed `_v` from `CodeBlob::print*_on(st)` methods to reduce scope of VM changes.  But I have to add `_impl` suffix to these methods in CodeBlob subclasses.

I renamed `nmethod::print_on(st, msg);` to `print_on_with_msg(at, msg) to avoid naming conflict C++ complains about. It cased change in `dependencyContext.cpp`.

I made `CodeBlob::Vptr` class abstract as suggested.

I added empty `Vptr` class to `RuntimeBlob` because it is referenced in subclasses and corrected extensions in sublcasses to avoid mistakes @xmas92 pointed.

I also did some arguments renaming in SA in `CodeCache.java` as requested.

Tier1-5 testing passed.

Ready for new round of reviews.

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PR Comment: https://git.openjdk.org/jdk/pull/23533#issuecomment-2660770028