S390: Refactor wmemchr ifunc handling.

The ifunc handling for wmemchr is adjusted in order to omit ifunc
if the minimum architecture level already supports newer CPUs by default.
Unfortunately the c ifunc variant can't be omitted at all as it is used
by the z13 ifunc variant as fallback if the pointers are not 4-byte aligned.
Glibc internal calls will use the "newer" ifunc variant.

ChangeLog:

	* sysdeps/s390/multiarch/Makefile
	(sysdep_routines): Remove wmemchr variants.
	* sysdeps/s390/Makefile (sysdep_routines): Add wmemchr variants.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Refactor ifunc handling for wmemchr.
	* sysdeps/s390/multiarch/wmemchr-c.c: Move to ...
	* sysdeps/s390/wmemchr-c.c: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/wmemchr-vx.S: Move to ...
	* sysdeps/s390/wmemchr-vx.S: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/wmemchr.c: Move to ...
	* sysdeps/s390/wmemchr.c: ... here and adjust ifunc handling.
	* sysdeps/s390/ifunc-wmemchr.h: New file.

1 files changed, 44 insertions, 0 deletions

diff --git a/sysdeps/s390/wmemchr-c.c b/sysdeps/s390/wmemchr-c.c
new file mode 100644
index 0000000000..bb2526e76c
--- /dev/null
+++ b/sysdeps/s390/wmemchr-c.c
@@ -0,0 +1,44 @@
+/* Default wmemchr implementation for S/390.
+   Copyright (C) 2015-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <ifunc-wmemchr.h>
+
+#if HAVE_WMEMCHR_C
+# if HAVE_WMEMCHR_IFUNC || HAVE_WMEMCHR_Z13
+#  define WMEMCHR WMEMCHR_C
+
+#  undef weak_alias
+#  define weak_alias(name, alias)
+
+#  if defined SHARED && IS_IN (libc)
+#   undef libc_hidden_weak
+#   define libc_hidden_weak(name)
+#   undef libc_hidden_def
+#   if ! defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+#    define libc_hidden_def(name)					\
+  __hidden_ver1 (__wmemchr_c, __GI_wmemchr, __wmemchr_c)  __attribute__((weak)); \
+  strong_alias (__wmemchr_c, __wmemchr_c_1);				\
+  __hidden_ver1 (__wmemchr_c_1, __GI___wmemchr, __wmemchr_c_1);
+#   else
+#    define libc_hidden_def(name)
+#   endif
+#  endif
+# endif
+
+# include <wcsmbs/wmemchr.c>
+#endif