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| author | Noah Goldstein <goldstein.w.n@gmail.com> | 2021-10-21 15:54:57 -0500 |
|---|---|---|
| committer | Noah Goldstein <goldstein.w.n@gmail.com> | 2021-10-26 16:51:29 -0500 |
| commit | 44829b3ddb64e99e37343a0f25b2c082387d31a5 (patch) | |
| tree | ba9565215210f530296dd4456816fc69f593e542 /sysdeps/i386/i686 | |
| parent | 8438135d3481853e300e1043cfee3946dadb28b3 (diff) | |
| download | glibc-44829b3ddb64e99e37343a0f25b2c082387d31a5.tar.gz | |
String: Add support for __memcmpeq() ABI on all targets
No bug.
This commit adds support for __memcmpeq() as a new ABI for all
targets. In this commit __memcmpeq() is implemented only as an alias
to the corresponding targets memcmp() implementation. __memcmpeq() is
added as a new symbol starting with GLIBC_2.35 and defined in string.h
with comments explaining its behavior. Basic tests that it is callable
and works where added in string/tester.c
As discussed in the proposal "Add new ABI '__memcmpeq()' to libc"
__memcmpeq() is essentially a reserved namespace for bcmp(). The means
is shares the same specifications as memcmp() except the return value
for non-equal byte sequences is any non-zero value. This is less
strict than memcmp()'s return value specification and can be better
optimized when a boolean return is all that is needed.
__memcmpeq() is meant to only be called by compilers if they can prove
that the return value of a memcmp() call is only used for its boolean
value.
All tests in string/tester.c passed. As well build succeeds on
x86_64-linux-gnu target.
Diffstat (limited to 'sysdeps/i386/i686')
| -rw-r--r-- | sysdeps/i386/i686/memcmp.S | 2 | ||||
| -rw-r--r-- | sysdeps/i386/i686/multiarch/memcmp-ia32.S | 3 | ||||
| -rw-r--r-- | sysdeps/i386/i686/multiarch/memcmp.c | 1 |
3 files changed, 6 insertions, 0 deletions
diff --git a/sysdeps/i386/i686/memcmp.S b/sysdeps/i386/i686/memcmp.S index b26b124fad..90266d904b 100644 --- a/sysdeps/i386/i686/memcmp.S +++ b/sysdeps/i386/i686/memcmp.S @@ -405,4 +405,6 @@ L(table_32bytes) : #undef bcmp weak_alias (memcmp, bcmp) +#undef __memcmpeq +strong_alias (memcmp, __memcmpeq) libc_hidden_builtin_def (memcmp) diff --git a/sysdeps/i386/i686/multiarch/memcmp-ia32.S b/sysdeps/i386/i686/multiarch/memcmp-ia32.S index 5f6658b89a..a5b5c3d349 100644 --- a/sysdeps/i386/i686/multiarch/memcmp-ia32.S +++ b/sysdeps/i386/i686/multiarch/memcmp-ia32.S @@ -30,6 +30,9 @@ # undef weak_alias # define weak_alias(original, alias) + +# undef strong_alias +# define strong_alias(original, alias) #endif #include <sysdeps/i386/i686/memcmp.S> diff --git a/sysdeps/i386/i686/multiarch/memcmp.c b/sysdeps/i386/i686/multiarch/memcmp.c index 6e058a8857..3b2815edbc 100644 --- a/sysdeps/i386/i686/multiarch/memcmp.c +++ b/sysdeps/i386/i686/multiarch/memcmp.c @@ -29,4 +29,5 @@ libc_ifunc_redirected (__redirect_memcmp, memcmp, IFUNC_SELECTOR ()); weak_alias (memcmp, bcmp) +strong_alias (memcmp, __memcmpeq) #endif |