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, 53 insertions, 0 deletions

diff --git a/sysdeps/s390/ifunc-wmemchr.h b/sysdeps/s390/ifunc-wmemchr.h
new file mode 100644
index 0000000..0610cfb
--- /dev/null
+++ b/sysdeps/s390/ifunc-wmemchr.h
@@ -0,0 +1,53 @@
+/* wmemchr variant information on S/390 version.
+   Copyright (C) 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/>.  */
+
+#if defined USE_MULTIARCH && IS_IN (libc)		\
+  && ! defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define HAVE_WMEMCHR_IFUNC	1
+#else
+# define HAVE_WMEMCHR_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_WMEMCHR_IFUNC_AND_VX_SUPPORT HAVE_WMEMCHR_IFUNC
+#else
+# define HAVE_WMEMCHR_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define WMEMCHR_DEFAULT	WMEMCHR_Z13
+/* The z13 ifunc variant is using the common code variant as fallback!  */
+# define HAVE_WMEMCHR_C		1
+# define HAVE_WMEMCHR_Z13	1
+#else
+# define WMEMCHR_DEFAULT	WMEMCHR_C
+# define HAVE_WMEMCHR_C		1
+# define HAVE_WMEMCHR_Z13	HAVE_WMEMCHR_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_WMEMCHR_C
+# define WMEMCHR_C		__wmemchr_c
+#else
+# define WMEMCHR_C		NULL
+#endif
+
+#if HAVE_WMEMCHR_Z13
+# define WMEMCHR_Z13		__wmemchr_vx
+#else
+# define WMEMCHR_Z13		NULL
+#endif