RFR: 8329258: TailCall should not use frame pointer register for jump target [v4]

[Dean Long]

On Fri, 12 Apr 2024 13:23:46 GMT, Boris Ulasevich <bulasevich at openjdk.org> wrote:

> > I think other platforms are affected as well but I don't have the hardware to test there.
> > @bulasevich (ARM32), could you please have a look?
> 
> Hi. I checked ARM32. R11 (FP) is a common register that is not just dedicated solely to the frame pointer. And with a given test and patch I can not reproduce SIGSEGV on ARM32 platform. So I think ARM32 is not affected.

It looks like ARM32 is safe because the rules use specific, "bound" registers.  If they used something generic like iRegP, I think the callee-saved R11 would still be in danger of getting trashed.

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

PR Comment: https://git.openjdk.org/jdk/pull/18716#issuecomment-2052403066