RFR: JDK-8283326: Implement SafeFetch statically

[Thomas Stuefe]

On Mon, 11 Apr 2022 06:24:05 GMT, David Holmes <dholmes at openjdk.org> wrote:

> Hi Thomas,
> 
> This looks really good! Definite approval in principle. I can't comment on the details of the .S files. A few nits and comments. Main is comment is that SAFEFETCH_METHOD_x defines don't seem to actually be needed ??
> 
> Thanks, David

Thank you David!

SAFEFETCH_METHOD_xx was supposed to be a clean separation between safefetch method and platform, since there is no clear 1:1 relation and you can, and may need to, mix and match. Examples: 
- On Posix platforms you can use either static assembly or setjmp, and need to exclude one of them from compilation - either build safefetch_xx_xx.S, or build safefetch_sigjmp.cpp.
- On Windows, we use SEH, but I don't know yet if that works for Windows aarch64, and we still may need to switch to static assembly for this platform. I hope to avoid this though since MASM is a pain.

Therefore I'd like to keep the separation between SafeFetch method and platform, at least for now. Makes it easer to switch back and forth, and I find it actually cleaner.

Cheers Thomas

-------------

PR: https://git.openjdk.java.net/jdk/pull/7865