Re: [tip:x86/seves] BUILD SUCCESS WITH WARNING e6eb15c9ba3165698488ae5c34920eea20eaa38e

Nick Desaulniers
2020-09-15T22:03:04Z

On Tue, Sep 15, 2020 at 2:50 PM Arvind Sankar <nivedita@alum.mit.edu> wrote:
>
> On Tue, Sep 15, 2020 at 10:49:12PM +0200, Borislav Petkov wrote:
> >
> > (Btw, clang doesn't need to add that "xor %eax,%eax" - panic() should not be
> > returning, ever. :-))
> >
>
> I think this is because panic() is varargs, and clang doesn't support
> gcc's -mskip-rax-setup. The normal ABI requires the caller to set RAX to
> the number of arguments in vector registers.
>
> https://patchwork.ozlabs.org/project/gcc/patch/20141218131150.GA32638@intel.com/

Thanks for the report. Filed
https://bugs.llvm.org/show_bug.cgi?id=47538. Do you have an account
there Arvind so that I can CC you on them?

Yikes, it looks like gcc 5.0 supports that. We'd better get to
implementing that lest someone try to remove the cc-option on it soon.
--
Thanks,
~Nick Desaulniers