RFR: 8318609: Upcall stubs should be smaller

[Feilong Jiang]

On Fri, 20 Oct 2023 16:17:17 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> We can use `resolve_global_jobject` (introduced by [JDK-8299089](https://bugs.openjdk.org/browse/JDK-8299089)) because we know that the handle is created by `JNIHandles::make_global` in `UL_MakeUpcallStub`. That creates much shorter code.
> 
> Size reduced from 1360 bytes to 648 bytes on x64 for a trivial upcall using G1.

As I remember it was measured before: https://github.com/openjdk/jdk/pull/12908#issuecomment-1461390976

I would take another look.

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PR Comment: https://git.openjdk.org/jdk/pull/16290#issuecomment-1773083080