Re: [PATCH 3/3] powerpc: Fix powerpc64 strchrnul build with old gcc

[Carlos O'Donell <carlos@redhat.com>]

On 7/24/23 13:15, Adhemerval Zanella via Libc-alpha wrote:
> The compiler might not see that internal definition is an alias
> due the libc_ifunc macro, which redefines __strchrnul.  With
> gcc 6 it fails with:
> 
> In file included from <command-line>:0:0:
> ./../include/libc-symbols.h:472:33: error: ‘__EI___strchrnul’ aliased to
> undefined symbol ‘__GI___strchrnul’
>    extern thread __typeof (name) __EI_##name \
>                                  ^
> ./../include/libc-symbols.h:468:3: note: in expansion of macro
> ‘__hidden_ver2’
>    __hidden_ver2 (, local, internal, name)
>    ^~~~~~~~~~~~~
> ./../include/libc-symbols.h:476:29: note: in expansion of macro
> ‘__hidden_ver1’
>  #  define hidden_def(name)  __hidden_ver1(__GI_##name, name, name);
>                              ^~~~~~~~~~~~~
> ./../include/libc-symbols.h:557:32: note: in expansion of macro
> ‘hidden_def’
>  # define libc_hidden_def(name) hidden_def (name)
>                                 ^~~~~~~~~~
> ../sysdeps/powerpc/powerpc64/multiarch/strchrnul.c:38:1: note: in
> expansion of macro ‘libc_hidden_def’
>  libc_hidden_def (__strchrnul)
>  ^~~~~~~~~~~~~~~
> 
> Use libc_ifunc_hidden as stpcpy.  Checked on powerpc64 with
> gcc 6 and gcc 13.

Using the _hidden variant here is OK.

LGTM.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>


> ---
>  sysdeps/powerpc/powerpc64/multiarch/strchrnul.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c b/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c
> index 94873507a6..87dd41f72d 100644
> --- a/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c
> +++ b/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c
> @@ -27,13 +27,13 @@ extern __typeof (__strchrnul) __strchrnul_power8 attribute_hidden;
>  
>  /* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
>     ifunc symbol properly.  */
> -libc_ifunc (__strchrnul,
> -	    (hwcap2 & PPC_FEATURE2_ARCH_2_07
> -	     && hwcap & PPC_FEATURE_HAS_ALTIVEC)
> -	    ? __strchrnul_power8 :
> -	    (hwcap & PPC_FEATURE_ARCH_2_06)
> -            ? __strchrnul_power7
> -            : __strchrnul_ppc);
> +libc_ifunc_hidden (__strchrnul, __strchrnul,
> +		   (hwcap2 & PPC_FEATURE2_ARCH_2_07
> +		    && hwcap & PPC_FEATURE_HAS_ALTIVEC)
> +		   ? __strchrnul_power8 :
> +		   (hwcap & PPC_FEATURE_ARCH_2_06)
> +		   ? __strchrnul_power7
> +		   : __strchrnul_ppc);
>  
>  libc_hidden_def (__strchrnul)
>  weak_alias (__strchrnul, strchrnul)

-- 
Cheers,
Carlos.