S390: Refactor wcsncat ifunc handling.

The ifunc handling for wcsncat 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.

ChangeLog:

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

7 files changed, 101 insertions, 19 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index f393a2b1ef..cb8dd2134f 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -89,5 +89,6 @@ sysdep_routines += wcslen wcslen-vx wcslen-c \
 		   wcpcpy wcpcpy-vx wcpcpy-c \
 		   wcsncpy wcsncpy-vx wcsncpy-c \
 		   wcpncpy wcpncpy-vx wcpncpy-c \
-		   wcscat wcscat-vx wcscat-c
+		   wcscat wcscat-vx wcscat-c \
+		   wcsncat wcsncat-vx wcsncat-c
 endif
diff --git a/sysdeps/s390/ifunc-wcsncat.h b/sysdeps/s390/ifunc-wcsncat.h
new file mode 100644
index 0000000000..99495e0e64
--- /dev/null
+++ b/sysdeps/s390/ifunc-wcsncat.h
@@ -0,0 +1,53 @@
+/* wcsncat 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_WCSNCAT_IFUNC	1
+#else
+# define HAVE_WCSNCAT_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_WCSNCAT_IFUNC_AND_VX_SUPPORT HAVE_WCSNCAT_IFUNC
+#else
+# define HAVE_WCSNCAT_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define WCSNCAT_DEFAULT	WCSNCAT_Z13
+/* The z13 ifunc variant is using the common code variant as fallback!  */
+# define HAVE_WCSNCAT_C		1
+# define HAVE_WCSNCAT_Z13	1
+#else
+# define WCSNCAT_DEFAULT	WCSNCAT_C
+# define HAVE_WCSNCAT_C		1
+# define HAVE_WCSNCAT_Z13	HAVE_WCSNCAT_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_WCSNCAT_C
+# define WCSNCAT_C		__wcsncat_c
+#else
+# define WCSNCAT_C		NULL
+#endif
+
+#if HAVE_WCSNCAT_Z13
+# define WCSNCAT_Z13		__wcsncat_vx
+#else
+# define WCSNCAT_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 617017496c..6cb75950c2 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),wcsmbs)
-sysdep_routines += wcsncat wcsncat-vx wcsncat-c \
-		   wcscmp wcscmp-vx wcscmp-c \
+sysdep_routines += wcscmp wcscmp-vx wcscmp-c \
 		   wcsncmp wcsncmp-vx wcsncmp-c \
 		   wcschr wcschr-vx wcschr-c \
 		   wcschrnul wcschrnul-vx wcschrnul-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index b05bd35fd8..7b7b1e7497 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -53,6 +53,7 @@
 #include <ifunc-wcsncpy.h>
 #include <ifunc-wcpncpy.h>
 #include <ifunc-wcscat.h>
+#include <ifunc-wcsncat.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -515,6 +516,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_WCSCAT_IFUNC  */
 
+#if HAVE_WCSNCAT_IFUNC
+    IFUNC_IMPL (i, name, wcsncat,
+# if HAVE_WCSNCAT_Z13
+		IFUNC_IMPL_ADD (array, i, wcsncat,
+				dl_hwcap & HWCAP_S390_VX, WCSNCAT_Z13)
+# endif
+# if HAVE_WCSNCAT_C
+		IFUNC_IMPL_ADD (array, i, wcsncat, 1, WCSNCAT_C)
+# endif
+		)
+#endif /* HAVE_WCSNCAT_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -523,8 +536,6 @@ __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 (wcsncat);
-
   IFUNC_VX_IMPL (wcscmp);
 
   IFUNC_VX_IMPL (wcsncmp);
diff --git a/sysdeps/s390/multiarch/wcsncat-c.c b/sysdeps/s390/wcsncat-c.c
index 2cf1a76385..5782d5cb28 100644
--- a/sysdeps/s390/multiarch/wcsncat-c.c
+++ b/sysdeps/s390/wcsncat-c.c
@@ -16,10 +16,12 @@
    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 WCSNCAT  __wcsncat_c
+#include <ifunc-wcsncat.h>
+
+#if HAVE_WCSNCAT_C
+# if HAVE_WCSNCAT_IFUNC || HAVE_WCSNCAT_Z13
+#  define WCSNCAT WCSNCAT_C
+# endif
 
-# include <wchar.h>
-extern __typeof (wcsncat) __wcsncat_c;
 # include <wcsmbs/wcsncat.c>
 #endif
diff --git a/sysdeps/s390/multiarch/wcsncat-vx.S b/sysdeps/s390/wcsncat-vx.S
index 1d3935690d..7c89d3d856 100644
--- a/sysdeps/s390/multiarch/wcsncat-vx.S
+++ b/sysdeps/s390/wcsncat-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-wcsncat.h>
+#if HAVE_WCSNCAT_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -40,7 +41,7 @@
    -v18=part of src
    -v31=register save area for r6, r7
 */
-ENTRY(__wcsncat_vx)
+ENTRY(WCSNCAT_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -260,6 +261,10 @@ ENTRY(__wcsncat_vx)
 	j	.Lcpy_lt64
 
 .Lfallback:
-	jg	__wcsncat_c
-END(__wcsncat_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+	jg	WCSNCAT_C
+END(WCSNCAT_Z13)
+
+# if ! HAVE_WCSNCAT_IFUNC
+strong_alias (WCSNCAT_Z13, wcsncat)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/wcsncat.c b/sysdeps/s390/wcsncat.c
index c49b8ff786..722429fd5b 100644
--- a/sysdeps/s390/multiarch/wcsncat.c
+++ b/sysdeps/s390/wcsncat.c
@@ -16,12 +16,23 @@
    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-wcsncat.h>
+
+#if HAVE_WCSNCAT_IFUNC
 # include <wchar.h>
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2 (__wcsncat, wcsncat)
+# if HAVE_WCSNCAT_C
+extern __typeof (wcsncat) WCSNCAT_C attribute_hidden;
+# endif
+
+# if HAVE_WCSNCAT_Z13
+extern __typeof (wcsncat) WCSNCAT_Z13 attribute_hidden;
+# endif
 
-#else
-# include <wcsmbs/wcsncat.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+s390_libc_ifunc_expr (wcsncat, wcsncat,
+		      (HAVE_WCSNCAT_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? WCSNCAT_Z13
+		      : WCSNCAT_DEFAULT
+		      )
+#endif