S390: Refactor strrchr ifunc handling.

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

7 files changed, 113 insertions, 22 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index 07ec5e969f..c423c80a43 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -71,5 +71,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   strcmp strcmp-vx strcmp-z900 \
 		   strncmp strncmp-vx strncmp-c \
 		   strchr strchr-vx strchr-c \
-		   strchrnul strchrnul-vx strchrnul-c
+		   strchrnul strchrnul-vx strchrnul-c \
+		   strrchr strrchr-vx strrchr-c
 endif
diff --git a/sysdeps/s390/ifunc-strrchr.h b/sysdeps/s390/ifunc-strrchr.h
new file mode 100644
index 0000000000..7185fc3260
--- /dev/null
+++ b/sysdeps/s390/ifunc-strrchr.h
@@ -0,0 +1,52 @@
+/* strrchr 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_STRRCHR_IFUNC	1
+#else
+# define HAVE_STRRCHR_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STRRCHR_IFUNC_AND_VX_SUPPORT HAVE_STRRCHR_IFUNC
+#else
+# define HAVE_STRRCHR_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STRRCHR_DEFAULT	STRRCHR_Z13
+# define HAVE_STRRCHR_C		0
+# define HAVE_STRRCHR_Z13	1
+#else
+# define STRRCHR_DEFAULT	STRRCHR_C
+# define HAVE_STRRCHR_C		1
+# define HAVE_STRRCHR_Z13	HAVE_STRRCHR_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STRRCHR_C
+# define STRRCHR_C		__strrchr_c
+#else
+# define STRRCHR_C		NULL
+#endif
+
+#if HAVE_STRRCHR_Z13
+# define STRRCHR_Z13		__strrchr_vx
+#else
+# define STRRCHR_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 999a979fee..c826755558 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += strrchr strrchr-vx strrchr-c \
-		   strspn strspn-vx strspn-c \
+sysdep_routines += strspn strspn-vx strspn-c \
 		   strpbrk strpbrk-vx strpbrk-c \
 		   strcspn strcspn-vx strcspn-c \
 		   memchr memchr-vx \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 0a47ffeac3..60cd705ffa 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -38,6 +38,7 @@
 #include <ifunc-strncmp.h>
 #include <ifunc-strchr.h>
 #include <ifunc-strchrnul.h>
+#include <ifunc-strrchr.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -320,6 +321,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STRCHRNUL_IFUNC  */
 
+#if HAVE_STRRCHR_IFUNC
+    IFUNC_IMPL (i, name, strrchr,
+# if HAVE_STRRCHR_Z13
+		IFUNC_IMPL_ADD (array, i, strrchr,
+				dl_hwcap & HWCAP_S390_VX, STRRCHR_Z13)
+# endif
+# if HAVE_STRRCHR_C
+		IFUNC_IMPL_ADD (array, i, strrchr, 1, STRRCHR_C)
+# endif
+		)
+#endif /* HAVE_STRRCHR_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -352,7 +365,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcschrnul);
 
-  IFUNC_VX_IMPL (strrchr);
   IFUNC_VX_IMPL (wcsrchr);
 
   IFUNC_VX_IMPL (strspn);
diff --git a/sysdeps/s390/multiarch/strrchr-c.c b/sysdeps/s390/strrchr-c.c
index 53ceb8086f..615f16da7d 100644
--- a/sysdeps/s390/multiarch/strrchr-c.c
+++ b/sysdeps/s390/strrchr-c.c
@@ -16,14 +16,18 @@
    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 STRRCHR  __strrchr_c
-# undef weak_alias
-# ifdef SHARED
-#  undef libc_hidden_builtin_def
-#  define libc_hidden_builtin_def(name)				\
+#include <ifunc-strrchr.h>
+
+#if HAVE_STRRCHR_C
+# if HAVE_STRRCHR_IFUNC
+#  define STRRCHR STRRCHR_C
+#  undef weak_alias
+#  if defined SHARED && IS_IN (libc)
+#   undef libc_hidden_builtin_def
+#   define libc_hidden_builtin_def(name)			\
      __hidden_ver1 (__strrchr_c, __GI_strrchr, __strrchr_c);
-# endif /* SHARED */
+#  endif
+# endif
 
 # include <string/strrchr.c>
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+#endif
diff --git a/sysdeps/s390/multiarch/strrchr-vx.S b/sysdeps/s390/strrchr-vx.S
index 8b3b989631..5f4ac14ee3 100644
--- a/sysdeps/s390/multiarch/strrchr-vx.S
+++ b/sysdeps/s390/strrchr-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-strrchr.h>
+
+#if HAVE_STRRCHR_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -39,7 +41,7 @@
    -v19=part of s with last occurence of c.
    -v20=permute pattern
 */
-ENTRY(__strrchr_vx)
+ENTRY(STRRCHR_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -176,5 +178,15 @@ ENTRY(__strrchr_vx)
 .Lpermute_mask:
 	.byte	0x0F,0x0E,0x0D,0x0C,0x0B,0x0A,0x09,0x08
 	.byte	0x07,0x06,0x05,0x04,0x03,0x02,0x01,0x00
-END(__strrchr_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(STRRCHR_Z13)
+
+# if ! HAVE_STRRCHR_IFUNC
+strong_alias (STRRCHR_Z13, strrchr)
+weak_alias (strrchr, rindex)
+# endif
+
+# if ! HAVE_STRRCHR_C && defined SHARED && IS_IN (libc)
+strong_alias (STRRCHR_Z13, __GI_strrchr)
+# endif
+
+#endif /* HAVE_STRRCHR_Z13  */
diff --git a/sysdeps/s390/multiarch/strrchr.c b/sysdeps/s390/strrchr.c
index e00e25a3a4..9a8cecff0b 100644
--- a/sysdeps/s390/multiarch/strrchr.c
+++ b/sysdeps/s390/strrchr.c
@@ -16,15 +16,26 @@
    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-strrchr.h>
+
+#if HAVE_STRRCHR_IFUNC
 # define strrchr __redirect_strrchr
 # include <string.h>
 # undef strrchr
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2_redirected (__redirect_strrchr, __strrchr, strrchr)
-weak_alias (strrchr, rindex);
+# if HAVE_STRRCHR_C
+extern __typeof (__redirect_strrchr) STRRCHR_C attribute_hidden;
+# endif
+
+# if HAVE_STRRCHR_Z13
+extern __typeof (__redirect_strrchr) STRRCHR_Z13 attribute_hidden;
+# endif
 
-#else
-# include <string/strrchr.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+s390_libc_ifunc_expr (__redirect_strrchr, strrchr,
+		      (HAVE_STRRCHR_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STRRCHR_Z13
+		      : STRRCHR_DEFAULT
+		      )
+weak_alias (strrchr, rindex)
+#endif /* HAVE_STRRCHR_IFUNC  */