Re: [PATCH 3/3] powerpc: Use default st{r,p}cpy optimization for POWER7

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 29/11/2016 12:46, Andreas Schwab wrote:
> On Jul 29 2015, Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> 
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/stpcpy-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/stpcpy-ppc64.c
>> new file mode 100644
>> index 0000000..6e437fb
>> --- /dev/null
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/stpcpy-ppc64.c
>> @@ -0,0 +1,39 @@
>> +/* Multiarch stpcpy for PPC64.
>> +   Copyright (C) 2015 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <string.h>
>> +
>> +extern __typeof (memcpy) __memcpy_ppc attribute_hidden;
>> +extern __typeof (strlen) __strlen_ppc attribute_hidden;
>> +extern __typeof (stpcpy) __stpcpy_ppc attribute_hidden;
>> +
>> +#define STPCPY __stpcpy_ppc
>> +#define memcpy __memcpy_ppc
>> +#define strlen __strlen_ppc
>> +
>> +#undef weak_alias
>> +#define weak_alias(name, aliasname) \
>> +  extern __typeof (__stpcpy_ppc) aliasname \
>> +    __attribute__ ((weak, alias ("__stpcpy_ppc")));
> 
> This creates a __GI_stpcpy alias that clashes with the IFUNC symbol in
> stpcpy.os.
> 
> Andreas.

Indeed there is not need to define the default version for internal version,
since ifunc should work for powerpc64.  I will fix it upstream by removing
the alias redefine.

Also unfortunately it seems mostly binutils do not warn for this potential
issue.  Did you find it thought a tool or reviewing the code?