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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-05-13 09:33:30 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-05-16 09:36:06 -0300 |
| commit | 9403b71ae97e3f1a91c796ddcbb4e6f044434734 (patch) | |
| tree | 7a36c6a109815737ff5700d55125042bd2d0951e /sysdeps/x86_64/memset.S | |
| parent | 7b1cfba79ee54221ffa7d7879433b7ee1728cd76 (diff) | |
| download | glibc-9403b71ae97e3f1a91c796ddcbb4e6f044434734.tar.gz glibc-9403b71ae97e3f1a91c796ddcbb4e6f044434734.tar.xz glibc-9403b71ae97e3f1a91c796ddcbb4e6f044434734.zip | |
x86_64: Remove bzero optimization
Both symbols are marked as legacy in POSIX.1-2001 and removed on
POSIX.1-2008, although the prototypes are defined for _GNU_SOURCE
or _DEFAULT_SOURCE.
GCC also replaces bcopy with a memmove and bzero with memset on default
configuration (to actually get a bzero libc call the code requires
to omit string.h inclusion and built with -fno-builtin), so it is
highly unlikely programs are actually calling libc bzero symbol.
On a recent Linux distro (Ubuntu 22.04), there is no bzero calls
by the installed binaries.
$ cat count_bstring.sh
#!/bin/bash
files=`IFS=':';for i in $PATH; do test -d "$i" && find "$i" -maxdepth 1 -executable -type f; done`
total=0
for file in $files; do
symbols=`objdump -R $file 2>&1`
if [ $? -eq 0 ]; then
ncalls=`echo $symbols | grep -w $1 | wc -l`
((total=total+ncalls))
if [ $ncalls -gt 0 ]; then
echo "$file: $ncalls"
fi
fi
done
echo "TOTAL=$total"
$ ./count_bstring.sh bzero
TOTAL=0
Checked on x86_64-linux-gnu.
Diffstat (limited to 'sysdeps/x86_64/memset.S')
| -rw-r--r-- | sysdeps/x86_64/memset.S | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/sysdeps/x86_64/memset.S b/sysdeps/x86_64/memset.S index af26e9cedc..a6eea61a4d 100644 --- a/sysdeps/x86_64/memset.S +++ b/sysdeps/x86_64/memset.S @@ -1,4 +1,4 @@ -/* memset/bzero -- set memory area to CH/0 +/* memset -- set memory area to CH/0 Optimized version for x86-64. Copyright (C) 2002-2022 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -35,9 +35,6 @@ punpcklwd %xmm0, %xmm0; \ pshufd $0, %xmm0, %xmm0 -# define BZERO_ZERO_VEC0() \ - pxor %xmm0, %xmm0 - # define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \ movd d, %xmm0; \ pshufd $0, %xmm0, %xmm0; \ @@ -56,10 +53,6 @@ # define MEMSET_SYMBOL(p,s) memset #endif -#ifndef BZERO_SYMBOL -# define BZERO_SYMBOL(p,s) __bzero -#endif - #ifndef WMEMSET_SYMBOL # define WMEMSET_CHK_SYMBOL(p,s) p # define WMEMSET_SYMBOL(p,s) __wmemset @@ -70,7 +63,6 @@ libc_hidden_builtin_def (memset) #if IS_IN (libc) -weak_alias (__bzero, bzero) libc_hidden_def (__wmemset) weak_alias (__wmemset, wmemset) libc_hidden_weak (wmemset) |