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x86: Fix strstr ifunc on clang

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Work around the clang limitation wrt inline function and attribute
definition, where it does not allow to 'add' new attribute if a
function is already defined:

Buildint with clang triggers multiple issue on how ifunc macro are
used:

  ../sysdeps/x86_64/multiarch/strstr.c:38:54: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
     38 | extern __typeof (__redirect_strstr) __strstr_generic attribute_hidden;
        |                                                      ^
  ./../include/libc-symbols.h:356:43: note: expanded from macro 'attribute_hidden'
    356 | # define attribute_hidden __attribute__ ((visibility ("hidden")))
        |                                           ^
  ../string/strstr.c:76:1: note: previous definition is here
     76 | STRSTR (const char *haystack, const char *needle)
        | ^
  ../sysdeps/x86_64/multiarch/strstr.c:27:16: note: expanded from macro 'STRSTR'
     27 | #define STRSTR __strstr_generic
        |                ^
  ../sysdeps/x86_64/multiarch/strstr.c:65:43: error: redefinition of '__libc_strstr'
     65 | libc_ifunc_redirected (__redirect_strstr, __libc_strstr, IFUNC_SELECTOR ());
        |                                           ^

And

  ../sysdeps/x86_64/multiarch/strstr.c:65:43: error: redefinition of '__libc_strstr'
     65 | libc_ifunc_redirected (__redirect_strstr, __libc_strstr, IFUNC_SELECTOR ());
        |                                           ^
  ../sysdeps/x86_64/multiarch/strstr.c:59:13: note: previous definition is here
     59 | libc_ifunc (__libc_strstr,
        |             ^

Refactor to use a auxiliary function like other selection (for instance,
x86_64/multiarch/strcmp.c).
This commit is contained in:
Adhemerval Zanella
2025-11-10 10:28:59 -03:00
parent edd4dc7dc8
commit 53ad1eae0f
1 changed files with 14 additions and 9 deletions
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23
sysdeps/x86_64/multiarch/strstr.c
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@@ -31,19 +31,24 @@
__hidden_ver1 (__strstr_generic, __GI_strstr, __strstr_generic);
#endif
#include "string/strstr.c"
extern __typeof (__redirect_strstr) __strstr_sse2_unaligned attribute_hidden;
extern __typeof (__redirect_strstr) __strstr_generic attribute_hidden;
#include "string/strstr.c"
#include "init-arch.h"
/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
ifunc symbol properly. */
extern __typeof (__redirect_strstr) __libc_strstr;
libc_ifunc (__libc_strstr,
HAS_ARCH_FEATURE (Fast_Unaligned_Load)
? __strstr_sse2_unaligned
: __strstr_generic)
static inline void *
IFUNC_SELECTOR (void)
{
const struct cpu_features *cpu_features = __get_cpu_features ();
if (CPU_FEATURES_ARCH_P (cpu_features, Fast_Unaligned_Load))
return __strstr_sse2_unaligned;
return __strstr_generic;
}
libc_ifunc_redirected (__redirect_strstr, __libc_strstr, IFUNC_SELECTOR ());
#undef strstr
strong_alias (__libc_strstr, strstr)