RFR: 8347396: Efficient TypeFunc creations [v2]

[Dean Long]

On Mon, 27 Oct 2025 05:11:47 GMT, Harshit470250 <duke at openjdk.org> wrote:

>> This PR do similar changes done by [JDK-8330851](https://bugs.openjdk.org/browse/JDK-8330851) on the GC TypeFunc creation as suggested by [JDK-8347396](https://bugs.openjdk.org/browse/JDK-8347396). As discussed in [https://github.com/openjdk/jdk/pull/21782#discussion_r1906535686,](https://github.com/openjdk/jdk/pull/21782#discussion_r1906535686) I have put guard on the shenandoah gc specific part of the code.
>
> Harshit470250 has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:
> 
>  - Merge master
>  - update make_barrier_type
>  - Merge branch 'openjdk:master' into new_pr
>  - Merge branch 'openjdk:master' into new_pr
>  - My chages

Yes, bring it over, as it's an improvement.  However, I was wondering if there was a way we can get rid of the remaining `#if INCLUDE_SHENANDOAHGC` in shared c2 code.  The first idea that I came up with is for the GC init to reference a callback function for C2, but I'm not sure if the complexity is worth it.

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PR Comment: https://git.openjdk.org/jdk/pull/27279#issuecomment-3600260250