On Tue, 15 Apr 2025 at 09:48, Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Thu, Apr 10, 2025 at 2:27 PM Ard Biesheuvel <ardb+...@google.com> wrote:
> >
> > From: Ard Biesheuvel <a...@kernel.org>
> >
> > Commit bde21de1205 ("i386: Honour -mdirect-extern-access when calling
> > __fentry__") updated the logic that emits mcount() / __fentry__() calls
> > into function prologues when profiling is enabled, to avoid GOT-based
> > indirect calls when a direct call would suffice.
> >
> > There are two problems with that change:
> > - it relies on -mdirect-extern-access rather than -fno-plt to decide
> > whether or not a direct [PLT based] call is appropriate;
> > - for the PLT case, it falls through to x86_print_call_or_nop(), which
> > does not emit the @PLT suffix, resulting in the wrong relocation to be
> > used (R_X86_64_PC32 instead of R_X86_64_PLT32)
> >
> > Fix this by testing flag_plt instead of ix86_direct_extern_access, and
> > updating x86_print_call_or_nop() to take flag_pic and flag_plt into
> > account. This also ensures that -mnop-mcount works as expected when
> > emitting the PLT based profiling calls.
> >
> > While at it, fix the 32-bit logic as well, and issue a PLT call unless
> > PLTs are explicitly disabled.
> >
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119386
> >
> > Signed-off-by: Ard Biesheuvel <a...@kernel.org>
> >
> > gcc/ChangeLog:
> >
> > PR target/119386
> > * config/i386/i386.cc (x86_print_call_or_nop): Add @PLT suffix
> > where appropriate.
> > (x86_function_profiler): Fall through to x86_print_call_or_nop()
> > for PIC codegen when flag_plt is set.
> >
> > gcc/testsuite/ChangeLog:
> >
> > PR target/119386
> > * gcc.target/i386/pr119386-1.c: New test.
> > * gcc.target/i386/pr119386-2.c: New test.
>
> OK if there are no further comments in the next day or two.
>
Thanks
> BTW: Do you have commit rights?
>
No I do not.
