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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/x86_64 | |
| parent | 8438135d3481853e300e1043cfee3946dadb28b3 (diff) | |
| download | glibc-44829b3ddb64e99e37343a0f25b2c082387d31a5.zip glibc-44829b3ddb64e99e37343a0f25b2c082387d31a5.tar.gz glibc-44829b3ddb64e99e37343a0f25b2c082387d31a5.tar.bz2 | |
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/x86_64')
| -rw-r--r-- | sysdeps/x86_64/memcmp.S | 2 | ||||
| -rw-r--r-- | sysdeps/x86_64/multiarch/memcmp-sse2.S | 3 | ||||
| -rw-r--r-- | sysdeps/x86_64/multiarch/memcmp.c | 2 |
3 files changed, 7 insertions, 0 deletions
diff --git a/sysdeps/x86_64/memcmp.S b/sysdeps/x86_64/memcmp.S index 870e15c..1b351ee 100644 --- a/sysdeps/x86_64/memcmp.S +++ b/sysdeps/x86_64/memcmp.S @@ -358,4 +358,6 @@ END(memcmp) #undef bcmp weak_alias (memcmp, bcmp) +#undef __memcmpeq +strong_alias (memcmp, __memcmpeq) libc_hidden_builtin_def (memcmp) diff --git a/sysdeps/x86_64/multiarch/memcmp-sse2.S b/sysdeps/x86_64/multiarch/memcmp-sse2.S index b135fa2..af737c5 100644 --- a/sysdeps/x86_64/multiarch/memcmp-sse2.S +++ b/sysdeps/x86_64/multiarch/memcmp-sse2.S @@ -26,6 +26,9 @@ # undef weak_alias # define weak_alias(ignored1, ignored2) + +# undef strong_alias +# define strong_alias(ignored1, ignored2) #endif #include <sysdeps/x86_64/memcmp.S> diff --git a/sysdeps/x86_64/multiarch/memcmp.c b/sysdeps/x86_64/multiarch/memcmp.c index fe725f3..4a3aad2 100644 --- a/sysdeps/x86_64/multiarch/memcmp.c +++ b/sysdeps/x86_64/multiarch/memcmp.c @@ -29,6 +29,8 @@ libc_ifunc_redirected (__redirect_memcmp, memcmp, IFUNC_SELECTOR ()); # undef bcmp weak_alias (memcmp, bcmp) +# undef __memcmpeq +strong_alias (memcmp, __memcmpeq) # ifdef SHARED __hidden_ver1 (memcmp, __GI_memcmp, __redirect_memcmp) |