S390: Refactor strcat ifunc handling.

The ifunc handling for strcat 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.
Glibc internal calls will then also use the "newer" ifunc variant.

ChangeLog:

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

7 files changed, 108 insertions, 21 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index f02afd4d02..3783f44252 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -65,5 +65,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   strcpy strcpy-vx strcpy-z900 \
 		   stpcpy stpcpy-vx stpcpy-c \
 		   strncpy strncpy-vx strncpy-z900 \
-		   stpncpy stpncpy-vx stpncpy-c
+		   stpncpy stpncpy-vx stpncpy-c \
+		   strcat strcat-vx strcat-c
 endif
diff --git a/sysdeps/s390/ifunc-strcat.h b/sysdeps/s390/ifunc-strcat.h
new file mode 100644
index 0000000000..6fd2f7dd31
--- /dev/null
+++ b/sysdeps/s390/ifunc-strcat.h
@@ -0,0 +1,52 @@
+/* strcat 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_STRCAT_IFUNC	1
+#else
+# define HAVE_STRCAT_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STRCAT_IFUNC_AND_VX_SUPPORT HAVE_STRCAT_IFUNC
+#else
+# define HAVE_STRCAT_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STRCAT_DEFAULT		STRCAT_Z13
+# define HAVE_STRCAT_C		0
+# define HAVE_STRCAT_Z13	1
+#else
+# define STRCAT_DEFAULT		STRCAT_C
+# define HAVE_STRCAT_C		1
+# define HAVE_STRCAT_Z13	HAVE_STRCAT_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STRCAT_C
+# define STRCAT_C		__strcat_c
+#else
+# define STRCAT_C		NULL
+#endif
+
+#if HAVE_STRCAT_Z13
+# define STRCAT_Z13		__strcat_vx
+#else
+# define STRCAT_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 3d97d21da1..9b66237aaf 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += strcat strcat-vx strcat-c \
-		   strncat strncat-vx strncat-c \
+sysdep_routines += strncat strncat-vx strncat-c \
 		   strcmp strcmp-vx \
 		   strncmp strncmp-vx strncmp-c \
 		   strchr strchr-vx strchr-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 021e9f247f..1b7f3df3a3 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -32,6 +32,7 @@
 #include <ifunc-stpcpy.h>
 #include <ifunc-strncpy.h>
 #include <ifunc-stpncpy.h>
+#include <ifunc-strcat.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -242,6 +243,17 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STPNCPY_IFUNC  */
 
+#if HAVE_STRCAT_IFUNC
+    IFUNC_IMPL (i, name, strcat,
+# if HAVE_STRCAT_Z13
+		IFUNC_IMPL_ADD (array, i, strcat,
+				dl_hwcap & HWCAP_S390_VX, STRCAT_Z13)
+# endif
+# if HAVE_STRCAT_C
+		IFUNC_IMPL_ADD (array, i, strcat, 1, STRCAT_C)
+# endif
+		)
+#endif /* HAVE_STRCAT_IFUNC  */
 
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
@@ -263,7 +275,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcpncpy);
 
-  IFUNC_VX_IMPL (strcat);
   IFUNC_VX_IMPL (wcscat);
 
   IFUNC_VX_IMPL (strncat);
diff --git a/sysdeps/s390/multiarch/strcat-c.c b/sysdeps/s390/strcat-c.c
index f871faa7b5..7accc6c7ef 100644
--- a/sysdeps/s390/multiarch/strcat-c.c
+++ b/sysdeps/s390/strcat-c.c
@@ -16,13 +16,17 @@
    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 STRCAT  __strcat_c
-# ifdef SHARED
-#  undef libc_hidden_builtin_def
-#  define libc_hidden_builtin_def(name)				\
-     __hidden_ver1 (__strcat_c, __GI_strcat, __strcat_c);
-# endif /* SHARED */
+#include <ifunc-strcat.h>
+
+#if HAVE_STRCAT_C
+# if HAVE_STRCAT_IFUNC
+# define STRCAT STRCAT_C
+#  if defined SHARED && IS_IN (libc)
+#   undef libc_hidden_builtin_def
+#   define libc_hidden_builtin_def(name)		\
+  __hidden_ver1 (__strcat_c, __GI_strcat, __strcat_c);
+#  endif
+# endif
 
 # include <string/strcat.c>
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+#endif
diff --git a/sysdeps/s390/multiarch/strcat-vx.S b/sysdeps/s390/strcat-vx.S
index 3abbbccced..218e301f10 100644
--- a/sysdeps/s390/multiarch/strcat-vx.S
+++ b/sysdeps/s390/strcat-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-strcat.h>
+#if HAVE_STRCAT_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -37,7 +38,7 @@
    -v17=index of zero
    -v18=part of src
 */
-ENTRY(__strcat_vx)
+ENTRY(STRCAT_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -157,5 +158,13 @@ ENTRY(__strcat_vx)
 	vstl	%v16,%r5,0(%r2)	/* Copy characters including zero.  */
 	lgr	%r2,%r0		/* Load saved dest-ptr.  */
 	br	%r14
-END(__strcat_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(STRCAT_Z13)
+
+# if ! HAVE_STRCAT_IFUNC
+strong_alias (STRCAT_Z13, strcat)
+# endif
+
+# if ! HAVE_STRCAT_C && defined SHARED && IS_IN (libc)
+strong_alias (STRCAT_Z13, __GI_strcat)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/strcat.c b/sysdeps/s390/strcat.c
index 7d4126b44f..d378519c8a 100644
--- a/sysdeps/s390/multiarch/strcat.c
+++ b/sysdeps/s390/strcat.c
@@ -16,14 +16,25 @@
    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-strcat.h>
+
+#if HAVE_STRCAT_IFUNC
 # define strcat __redirect_strcat
 # include <string.h>
 # undef strcat
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2_redirected (__redirect_strcat, __strcat, strcat)
+# if HAVE_STRCAT_C
+extern __typeof (__redirect_strcat) STRCAT_C attribute_hidden;
+# endif
+
+# if HAVE_STRCAT_Z13
+extern __typeof (__redirect_strcat) STRCAT_Z13 attribute_hidden;
+# endif
 
-#else
-# include <string/strcat.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+s390_libc_ifunc_expr (__redirect_strcat, strcat,
+		      (HAVE_STRCAT_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STRCAT_Z13
+		      : STRCAT_DEFAULT
+		      )
+#endif