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.

7 files changed, 126 insertions, 32 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index a9058047a9..17aabf328b 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -98,5 +98,6 @@ sysdep_routines += wcslen wcslen-vx wcslen-c \
 		   wcsrchr wcsrchr-vx wcsrchr-c \
 		   wcsspn wcsspn-vx wcsspn-c \
 		   wcspbrk wcspbrk-vx wcspbrk-c \
-		   wcscspn wcscspn-vx wcscspn-c
+		   wcscspn wcscspn-vx wcscspn-c \
+		   wmemchr wmemchr-vx wmemchr-c
 endif
diff --git a/sysdeps/s390/ifunc-wmemchr.h b/sysdeps/s390/ifunc-wmemchr.h
new file mode 100644
index 0000000000..0610cfb5d4
--- /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
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 5be6355423..92e28dc45d 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),wcsmbs)
-sysdep_routines += wmemchr wmemchr-vx wmemchr-c \
-		   wmemset wmemset-vx wmemset-c \
+sysdep_routines += wmemset wmemset-vx wmemset-c \
 		   wmemcmp wmemcmp-vx wmemcmp-c
 endif
 
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 7d8031a069..b5f55deb7f 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -62,6 +62,7 @@
 #include <ifunc-wcsspn.h>
 #include <ifunc-wcspbrk.h>
 #include <ifunc-wcscspn.h>
+#include <ifunc-wmemchr.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -632,6 +633,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_WCSCSPN_IFUNC  */
 
+#if HAVE_WMEMCHR_IFUNC
+    IFUNC_IMPL (i, name, wmemchr,
+# if HAVE_WMEMCHR_Z13
+		IFUNC_IMPL_ADD (array, i, wmemchr,
+				dl_hwcap & HWCAP_S390_VX, WMEMCHR_Z13)
+# endif
+# if HAVE_WMEMCHR_C
+		IFUNC_IMPL_ADD (array, i, wmemchr, 1, WMEMCHR_C)
+# endif
+		)
+#endif /* HAVE_WMEMCHR_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -640,8 +653,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			      __##FUNC##_vx)				\
 	      IFUNC_IMPL_ADD (array, i, FUNC, 1, __##FUNC##_c))
 
-  IFUNC_VX_IMPL (wmemchr);
-
   IFUNC_VX_IMPL (wmemset);
 
   IFUNC_VX_IMPL (wmemcmp);
diff --git a/sysdeps/s390/multiarch/wmemchr-c.c b/sysdeps/s390/wmemchr-c.c
index 089392b512..bb2526e76c 100644
--- a/sysdeps/s390/multiarch/wmemchr-c.c
+++ b/sysdeps/s390/wmemchr-c.c
@@ -16,22 +16,29 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
-# define WMEMCHR  __wmemchr_c
-
-# include <wchar.h>
-extern __typeof (wmemchr) __wmemchr_c;
-# undef weak_alias
-# define weak_alias(name, alias)
-# ifdef SHARED
-#  undef libc_hidden_def
-#  define libc_hidden_def(name)			\
-  __hidden_ver1 (__wmemchr_c, __GI___wmemchr, __wmemchr_c);
-#  undef libc_hidden_weak
-#  define libc_hidden_weak(name)					\
+#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);
-# endif /* SHARED */
+  __hidden_ver1 (__wmemchr_c_1, __GI___wmemchr, __wmemchr_c_1);
+#   else
+#    define libc_hidden_def(name)
+#   endif
+#  endif
+# endif
 
 # include <wcsmbs/wmemchr.c>
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+#endif
diff --git a/sysdeps/s390/multiarch/wmemchr-vx.S b/sysdeps/s390/wmemchr-vx.S
index db057b579a..72e9ef59af 100644
--- a/sysdeps/s390/multiarch/wmemchr-vx.S
+++ b/sysdeps/s390/wmemchr-vx.S
@@ -16,7 +16,8 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+#include <ifunc-wmemchr.h>
+#if HAVE_WMEMCHR_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -38,7 +39,7 @@
    -v17=index of found c
    -v18=c replicated
 */
-ENTRY(__wmemchr_vx)
+ENTRY(WMEMCHR_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -161,6 +162,17 @@ ENTRY(__wmemchr_vx)
 
 	j	.Llt64
 .Lfallback:
-	jg	__wmemchr_c
-END(__wmemchr_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+	jg	WMEMCHR_C
+END(WMEMCHR_Z13)
+
+# if ! HAVE_WMEMCHR_IFUNC
+strong_alias (WMEMCHR_Z13, __wmemchr)
+weak_alias (__wmemchr, wmemchr)
+# endif
+
+# if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT \
+	&& defined SHARED && IS_IN (libc)
+strong_alias (WMEMCHR_Z13, __GI___wmemchr)
+weak_alias (WMEMCHR_Z13, __GI_wmemchr)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/wmemchr.c b/sysdeps/s390/wmemchr.c
index 6b55c1d7fa..0d2fbb22c6 100644
--- a/sysdeps/s390/multiarch/wmemchr.c
+++ b/sysdeps/s390/wmemchr.c
@@ -16,7 +16,9 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+#include <ifunc-wmemchr.h>
+
+#if HAVE_WMEMCHR_IFUNC
 # define wmemchr __redirect_wmemchr
 # define __wmemchr __redirect___wmemchr
 # include <wchar.h>
@@ -24,9 +26,18 @@
 # undef __wmemchr
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc_redirected (__redirect___wmemchr, __wmemchr)
-weak_alias (__wmemchr, wmemchr)
+# if HAVE_WMEMCHR_C
+extern __typeof (__redirect___wmemchr) WMEMCHR_C attribute_hidden;
+# endif
 
-#else
-# include <wcsmbs/wmemchr.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+# if HAVE_WMEMCHR_Z13
+extern __typeof (__redirect___wmemchr) WMEMCHR_Z13 attribute_hidden;
+# endif
+
+s390_libc_ifunc_expr (__redirect___wmemchr, __wmemchr,
+		      (HAVE_WMEMCHR_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? WMEMCHR_Z13
+		      : WMEMCHR_DEFAULT
+		      )
+weak_alias (__wmemchr, wmemchr)
+#endif