S390: Refactor strchrnul ifunc handling.

The ifunc handling for strchrnul is adjusted in order to omit ifunc
variants if those will never be used as the minimum architecture level
already supports newer CPUs by default.

ChangeLog:

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

7 files changed, 106 insertions, 19 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index 59d6e845db..07ec5e969f 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -70,5 +70,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   strncat strncat-vx strncat-c \
 		   strcmp strcmp-vx strcmp-z900 \
 		   strncmp strncmp-vx strncmp-c \
-		   strchr strchr-vx strchr-c
+		   strchr strchr-vx strchr-c \
+		   strchrnul strchrnul-vx strchrnul-c
 endif
diff --git a/sysdeps/s390/ifunc-strchrnul.h b/sysdeps/s390/ifunc-strchrnul.h
new file mode 100644
index 0000000000..cac817e6f0
--- /dev/null
+++ b/sysdeps/s390/ifunc-strchrnul.h
@@ -0,0 +1,52 @@
+/* strchrnul 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_STRCHRNUL_IFUNC	1
+#else
+# define HAVE_STRCHRNUL_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STRCHRNUL_IFUNC_AND_VX_SUPPORT HAVE_STRCHRNUL_IFUNC
+#else
+# define HAVE_STRCHRNUL_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STRCHRNUL_DEFAULT	STRCHRNUL_Z13
+# define HAVE_STRCHRNUL_C	0
+# define HAVE_STRCHRNUL_Z13	1
+#else
+# define STRCHRNUL_DEFAULT	STRCHRNUL_C
+# define HAVE_STRCHRNUL_C	1
+# define HAVE_STRCHRNUL_Z13	HAVE_STRCHRNUL_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STRCHRNUL_C
+# define STRCHRNUL_C		__strchrnul_c
+#else
+# define STRCHRNUL_C		NULL
+#endif
+
+#if HAVE_STRCHRNUL_Z13
+# define STRCHRNUL_Z13		__strchrnul_vx
+#else
+# define STRCHRNUL_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index a8e9d0acd9..999a979fee 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += strchrnul strchrnul-vx strchrnul-c \
-		   strrchr strrchr-vx strrchr-c \
+sysdep_routines += strrchr strrchr-vx strrchr-c \
 		   strspn strspn-vx strspn-c \
 		   strpbrk strpbrk-vx strpbrk-c \
 		   strcspn strcspn-vx strcspn-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index e809ca3bac..0a47ffeac3 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -37,6 +37,7 @@
 #include <ifunc-strcmp.h>
 #include <ifunc-strncmp.h>
 #include <ifunc-strchr.h>
+#include <ifunc-strchrnul.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -307,6 +308,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STRCHR_IFUNC  */
 
+#if HAVE_STRCHRNUL_IFUNC
+    IFUNC_IMPL (i, name, strchrnul,
+# if HAVE_STRCHRNUL_Z13
+		IFUNC_IMPL_ADD (array, i, strchrnul,
+				dl_hwcap & HWCAP_S390_VX, STRCHRNUL_Z13)
+# endif
+# if HAVE_STRCHRNUL_C
+		IFUNC_IMPL_ADD (array, i, strchrnul, 1, STRCHRNUL_C)
+# endif
+		)
+#endif /* HAVE_STRCHRNUL_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -337,7 +350,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcschr);
 
-  IFUNC_VX_IMPL (strchrnul);
   IFUNC_VX_IMPL (wcschrnul);
 
   IFUNC_VX_IMPL (strrchr);
diff --git a/sysdeps/s390/multiarch/strchrnul-c.c b/sysdeps/s390/strchrnul-c.c
index 020cebcf3e..585273f5de 100644
--- a/sysdeps/s390/multiarch/strchrnul-c.c
+++ b/sysdeps/s390/strchrnul-c.c
@@ -16,11 +16,15 @@
    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 STRCHRNUL  __strchrnul_c
-# define __strchrnul STRCHRNUL
-# undef weak_alias
-# define weak_alias(name, alias)
+#include <ifunc-strchrnul.h>
+
+#if HAVE_STRCHRNUL_C
+# if HAVE_STRCHRNUL_IFUNC
+#  define STRCHRNUL STRCHRNUL_C
+#  define __strchrnul STRCHRNUL
+#  undef weak_alias
+#  define weak_alias(name, alias)
+# endif
 
 # include <string/strchrnul.c>
 #endif
diff --git a/sysdeps/s390/multiarch/strchrnul-vx.S b/sysdeps/s390/strchrnul-vx.S
index d561825e04..0cd587bc32 100644
--- a/sysdeps/s390/multiarch/strchrnul-vx.S
+++ b/sysdeps/s390/strchrnul-vx.S
@@ -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-strchrnul.h>
+
+#if HAVE_STRCHRNUL_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -35,7 +37,7 @@
    -v16=part of s
    -v18=vector with c replicated in every byte
 */
-ENTRY(__strchrnul_vx)
+ENTRY(STRCHRNUL_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -89,5 +91,11 @@ ENTRY(__strchrnul_vx)
 
 .Lend:
 	br	%r14
-END(__strchrnul_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(STRCHRNUL_Z13)
+
+# if ! HAVE_STRCHRNUL_IFUNC
+strong_alias (STRCHRNUL_Z13, __strchrnul)
+weak_alias (__strchrnul, strchrnul)
+# endif
+
+#endif /* HAVE_STRCHRNUL_Z13  */
diff --git a/sysdeps/s390/multiarch/strchrnul.c b/sysdeps/s390/strchrnul.c
index 62dfc6bd90..e9fefe1bdc 100644
--- a/sysdeps/s390/multiarch/strchrnul.c
+++ b/sysdeps/s390/strchrnul.c
@@ -16,13 +16,24 @@
    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-strchrnul.h>
+
+#if HAVE_STRCHRNUL_IFUNC
 # include <string.h>
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc (__strchrnul)
-weak_alias (__strchrnul, strchrnul)
+# if HAVE_STRCHRNUL_C
+extern __typeof (__strchrnul) STRCHRNUL_C attribute_hidden;
+# endif
 
-#else
-# include <string/strchrnul.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+# if HAVE_STRCHRNUL_Z13
+extern __typeof (__strchrnul) STRCHRNUL_Z13 attribute_hidden;
+# endif
+
+s390_libc_ifunc_expr (__strchrnul, __strchrnul,
+		      (HAVE_STRCHRNUL_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STRCHRNUL_Z13
+		      : STRCHRNUL_DEFAULT
+		      )
+weak_alias (__strchrnul, strchrnul)
+#endif /* HAVE_STRCHRNUL_IFUNC  */