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Re: [PATCH] i686: Add missing IS_IN (libc) guards to vectorized strcspn


On 06/14/2017 02:19 AM, Florian Weimer wrote:
> Since commit d957c4d3fa48d685ff2726c605c988127ef99395 (i386: Compile
> rtld-*.os with -mno-sse -mno-mmx -mfpmath=387), vector intrinsics can
> no longer be used in ld.so, even if the compiled code never makes it
> into the final ld.so link.  This commit adds the missing IS_IN (libc)
> guard to the SSE 4.2 strcspn implementation, so that it can be used from
> ld.so in the future.
> 
> 2017-06-14  Florian Weimer  <fweimer@redhat.com>
> 
> 	* sysdeps/i386/i686/multiarch/strcspn-c.c: Add IS_IN (libc) guard.
> 	* sysdeps/i386/i686/multiarch/varshift.c: Likewise.

This looks good to me.

We have struggled with these issues for years. I wish there was a more
automatic way to enable new functions for use in ld.so, but there isn't.

Out of curiosity, if you don't apply this patch, and use strcspn, does
the tst-ld-sse-use.sh test fail?
 
> diff --git a/sysdeps/i386/i686/multiarch/strcspn-c.c b/sysdeps/i386/i686/multiarch/strcspn-c.c
> index 6d61e19..ec230fb 100644
> --- a/sysdeps/i386/i686/multiarch/strcspn-c.c
> +++ b/sysdeps/i386/i686/multiarch/strcspn-c.c
> @@ -1,2 +1,4 @@
> -#define __strcspn_sse2 __strcspn_ia32
> -#include <sysdeps/x86_64/multiarch/strcspn-c.c>
> +#if IS_IN (libc)
> +# define __strcspn_sse2 __strcspn_ia32
> +# include <sysdeps/x86_64/multiarch/strcspn-c.c>
> +#endif
> diff --git a/sysdeps/i386/i686/multiarch/varshift.c b/sysdeps/i386/i686/multiarch/varshift.c
> index 7760b96..6742a35 100644
> --- a/sysdeps/i386/i686/multiarch/varshift.c
> +++ b/sysdeps/i386/i686/multiarch/varshift.c
> @@ -1 +1,3 @@
> -#include <sysdeps/x86_64/multiarch/varshift.c>
> +#if IS_IN (libc)
> +# include <sysdeps/x86_64/multiarch/varshift.c>
> +#endif
> 


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