There exist optimized memcpy functions on s390, but no optimized mempcpy.
This patch adds mempcpy entry points in memcpy.S files, which
use the memcpy implementation. Now mempcpy itself is also an IFUNC function
as memcpy is and the variants are listed in ifunc-impl-list.c.
The s390 string.h does not define _HAVE_STRING_ARCH_mempcpy.
Instead mempcpy string/string.h inlines memcpy() + n.
If n is constant and small enough, GCC emits instructions like mvi or mvc
and avoids the function call to memcpy.
If n is not constant, then memcpy is called and n is added afterwards.
If _HAVE_STRING_ARCH_mempcpy would be defined, mempcpy would be called in
every case.
According to PR70140 "Inefficient expansion of __builtin_mempcpy"
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70140) GCC should handle a
call to mempcpy in the same way as memcpy. Then either the mempcpy macro
in string/string.h has to be removed or _HAVE_STRING_ARCH_mempcpy has to
be defined for S390.
ChangeLog:
[BZ #19765]
* sysdeps/s390/mempcpy.S: New File.
* sysdeps/s390/multiarch/mempcpy.c: Likewise.
* sysdeps/s390/multiarch/Makefile (sysdep_routines): Add mempcpy.
* sysdeps/s390/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list):
Add mempcpy variants.
* sysdeps/s390/s390-32/memcpy.S: Add mempcpy entry point.
(memcpy): Adjust to be usable from mempcpy entry point.
(__memcpy_mvcle): Likewise.
* sysdeps/s390/s390-64/memcpy.S: Likewise.
* sysdeps/s390/s390-32/multiarch/memcpy-s390.S: Add entry points
____mempcpy_z196, ____mempcpy_z10 and add __GI_ symbols for mempcpy.
(__memcpy_z196): Adjust to be usable from mempcpy entry point.
(__memcpy_z10): Likewise.
* sysdeps/s390/s390-64/multiarch/memcpy-s390x.S: Likewise.
On s390, the memcpy, memcmp, memset functions are IFUNC symbols,
which are created with s390_libc_ifunc-macro.
This macro creates a __GI_ symbol which is set to the
ifunced symbol. Thus calls within libc.so to e.g. memcpy
result in a call to *ABS*+0x954c0@plt stub and afterwards
to the resolved memcpy-ifunc-variant.
This patch sets the __GI_ symbol to the default-ifunc-variant
to avoid the plt call. The __GI_ symbols are now created at the
default variant of ifunced function.
ChangeLog:
* sysdeps/s390/multiarch/ifunc-resolve.h (s390_libc_ifunc):
Remove __GI_ symbol.
* sysdeps/s390/s390-32/multiarch/memcmp-s390.S: Add __GI_memcmp symbol.
* sysdeps/s390/s390-64/multiarch/memcmp-s390x.S: Likewise.
* sysdeps/s390/s390-32/multiarch/memcpy-s390.S: Add __GI_memcpy symbol.
* sysdeps/s390/s390-64/multiarch/memcpy-s390x.S: Likewise.
* sysdeps/s390/s390-32/multiarch/memset-s390.S: Add __GI_memset symbol.
* sysdeps/s390/s390-64/multiarch/memset-s390x.S: Likewise.
On s390 all ifunc resolvers were implemented in multiarch/ifunc-resolve.c.
The resulting single object files has undefined references to all ifunc-functions.
This patch introduces one multiarch/<func>.c file for each of memcpy, memcmp
and memset with the function specific ifunc resolver. The different function
implementations are now implemented in multiarch/<func>-s390x.S
(moved from multiarch/<func>.S).
The new multiarch/ifunc-resolve.h file contains the ifunc-resolver macro
and other helper-macros. They are merged and are now used in common for
32/64bit. Therefore the __<func>_g5/__<func>_z900 functions were renamed to
__<func>_default.
This patch also enables testing the ifunc implementations by implementing
the function __libc_ifunc_impl_list. It uses the helper-macros of ifunc-resolve.h.
ChangeLog:
* sysdeps/s390/s390-32/multiarch/Makefile (sysdep_routines):
Remove ifunc-resolve, add memset-s390, memcpy-s390, memcmp-s390.
* sysdeps/s390/s390-32/multiarch/ifunc-resolve.c: Delete File.
* sysdeps/s390/s390-32/multiarch/memcmp.S: Move to ...
* sysdeps/s390/s390-32/multiarch/memcmp-s390.S: ... here.
(memcmp, bcmp): Use __memcmp_default as alias source.
* sysdeps/s390/s390-32/multiarch/memcmp.c: New File.
* sysdeps/s390/s390-32/memcmp.S (__memcmp_g5):
Rename to __memcmp_default.
* sysdeps/s390/s390-32/multiarch/memcpy.S: Move to ...
* sysdeps/s390/s390-32/multiarch/memcpy-s390.S: ... here.
(memcpy): Use __memcpy_default as alias source.
* sysdeps/s390/s390-32/multiarch/memcpy.c: New File.
* sysdeps/s390/s390-32/memcpy.S (__memcpy_g5):
Rename to __memcpy_default.
* sysdeps/s390/s390-32/multiarch/memset.S: Move to ...
* sysdeps/s390/s390-32/multiarch/memset-s390.S: ... here.
(memset): Use __memset_default as alias source.
* sysdeps/s390/s390-32/multiarch/memset.c: New File.
* sysdeps/s390/s390-32/memset.S (__memset_g5):
Rename to __memset_default.
* sysdeps/s390/s390-64/multiarch/Makefile (sysdep_routines):
Remove ifunc-resolve, add memset-s390x, memcpy-s390x, memcmp-s390x.
* sysdeps/s390/s390-64/multiarch/ifunc-resolve.c: Delete File.
* sysdeps/s390/s390-64/multiarch/memcmp.S: Move to ...
* sysdeps/s390/s390-64/multiarch/memcmp-s390x.S: ... here.
(memcmp, bcmp): Use __memcmp_default as alias source.
* sysdeps/s390/s390-64/multiarch/memcmp.c: New File.
* sysdeps/s390/s390-64/memcmp.S (__memcmp_z900):
Rename to __memcmp_default.
* sysdeps/s390/s390-64/multiarch/memcpy.S: Move to ...
* sysdeps/s390/s390-64/multiarch/memcpy-s390x.S: ... here.
(memcpy): Use __memcpy_default as alias source.
* sysdeps/s390/s390-64/multiarch/memcpy.c: New File.
* sysdeps/s390/s390-64/memcpy.S (__memcpy_z900):
Rename to __memcpy_default.
* sysdeps/s390/s390-64/multiarch/memset.S: Move to ...
* sysdeps/s390/s390-64/multiarch/memset-s390x.S: ... here.
(memset): Use __memset_default as alias source.
* sysdeps/s390/s390-64/multiarch/memset.c: New File.
* sysdeps/s390/s390-64/memset.S (__memset_z900):
Rename to __memset_default.
* sysdeps/s390/multiarch/ifunc-resolve.h: New File.
* sysdeps/s390/multiarch/ifunc-impl-list.c: New File.
