Re: [PATCH 2/3] aarch64: libgcc: add prototypes in cpuinfo

[Christophe Lyon]

On Fri, 4 Oct 2024 at 10:00, Kyrylo Tkachov <ktkac...@nvidia.com> wrote:
>
>
>
> > On 3 Oct 2024, at 21:44, Christophe Lyon <christophe.l...@linaro.org> wrote:
> >
> > External email: Use caution opening links or attachments
> >
> >
> > Add prototypes for __init_cpu_features_resolver and
> > __init_cpu_features to avoid warnings due to -Wmissing-prototypes.
> >
> >        libgcc/
> >        * config/aarch64/cpuinfo.c (__init_cpu_features_resolver): Add
> >        prototype.
> >        (__init_cpu_features): Likewise.
> > ---
> > libgcc/config/aarch64/cpuinfo.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/libgcc/config/aarch64/cpuinfo.c 
> > b/libgcc/config/aarch64/cpuinfo.c
> > index 4b94fca8695..c62a7453e8e 100644
> > --- a/libgcc/config/aarch64/cpuinfo.c
> > +++ b/libgcc/config/aarch64/cpuinfo.c
> > @@ -418,6 +418,7 @@ __init_cpu_features_constructor(unsigned long hwcap,
> >   setCPUFeature(FEAT_INIT);
> > }
> >
> > +void __init_cpu_features_resolver(unsigned long, const __ifunc_arg_t *);
> > void
> > __init_cpu_features_resolver(unsigned long hwcap, const __ifunc_arg_t *arg) 
> > {
> >   if (__aarch64_cpu_features.features)
> > @@ -425,6 +426,7 @@ __init_cpu_features_resolver(unsigned long hwcap, const 
> > __ifunc_arg_t *arg) {
> >   __init_cpu_features_constructor(hwcap, arg);
> > }
> >
> > +void __init_cpu_features(void);
> > void __attribute__ ((constructor))
> > __init_cpu_features(void) {
> >   unsigned long hwcap;
>
> I thought the intent of the missing-prototypes warning is to warn about 
> missing prototypes in a header file primarily.

Indeed, that's my understanding too....

> Should these prototypes go into gcc/common/config/aarch64/cpuinfo.h instead?
In that case, compilation of gcc/config/aarch64/aarch64.c fails because:
gcc/common/config/aarch64/cpuinfo.h:96:56: error: ‘__ifunc_arg_t’ does
not name a type
and it does not seem obvious to expose this type in aarch64.c

IIUC, these functions never have their prototypes exposed/used, and
I'm not even sure how __init_cpu_features is called: in
dispatch_function_versions(), I only see a reference to
__init_cpu_features_resolver?

(But I'm not at all familiar with this code)

Thanks,

Christophe


> Thanks,
> Kyrill
>
> > --
> > 2.34.1
> >
>