S390: Refactor strchr ifunc handling.

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

7 files changed, 113 insertions, 22 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index 3aaf5a0d40..59d6e845db 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -69,5 +69,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   strcat strcat-vx strcat-c \
 		   strncat strncat-vx strncat-c \
 		   strcmp strcmp-vx strcmp-z900 \
-		   strncmp strncmp-vx strncmp-c
+		   strncmp strncmp-vx strncmp-c \
+		   strchr strchr-vx strchr-c
 endif
diff --git a/sysdeps/s390/ifunc-strchr.h b/sysdeps/s390/ifunc-strchr.h
new file mode 100644
index 0000000000..cfeb00eeda
--- /dev/null
+++ b/sysdeps/s390/ifunc-strchr.h
@@ -0,0 +1,52 @@
+/* strchr 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_STRCHR_IFUNC	1
+#else
+# define HAVE_STRCHR_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STRCHR_IFUNC_AND_VX_SUPPORT HAVE_STRCHR_IFUNC
+#else
+# define HAVE_STRCHR_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STRCHR_DEFAULT		STRCHR_Z13
+# define HAVE_STRCHR_C		0
+# define HAVE_STRCHR_Z13	1
+#else
+# define STRCHR_DEFAULT		STRCHR_C
+# define HAVE_STRCHR_C		1
+# define HAVE_STRCHR_Z13	HAVE_STRCHR_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STRCHR_C
+# define STRCHR_C		__strchr_c
+#else
+# define STRCHR_C		NULL
+#endif
+
+#if HAVE_STRCHR_Z13
+# define STRCHR_Z13		__strchr_vx
+#else
+# define STRCHR_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 381376bf9f..a8e9d0acd9 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += strchr strchr-vx strchr-c \
-		   strchrnul strchrnul-vx strchrnul-c \
+sysdep_routines += strchrnul strchrnul-vx strchrnul-c \
 		   strrchr strrchr-vx strrchr-c \
 		   strspn strspn-vx strspn-c \
 		   strpbrk strpbrk-vx strpbrk-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index d982de5788..e809ca3bac 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -36,6 +36,7 @@
 #include <ifunc-strncat.h>
 #include <ifunc-strcmp.h>
 #include <ifunc-strncmp.h>
+#include <ifunc-strchr.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -294,6 +295,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STRNCMP_IFUNC  */
 
+#if HAVE_STRCHR_IFUNC
+    IFUNC_IMPL (i, name, strchr,
+# if HAVE_STRCHR_Z13
+		IFUNC_IMPL_ADD (array, i, strchr,
+				dl_hwcap & HWCAP_S390_VX, STRCHR_Z13)
+# endif
+# if HAVE_STRCHR_C
+		IFUNC_IMPL_ADD (array, i, strchr, 1, STRCHR_C)
+# endif
+		)
+#endif /* HAVE_STRCHR_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -322,7 +335,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcsncmp);
 
-  IFUNC_VX_IMPL (strchr);
   IFUNC_VX_IMPL (wcschr);
 
   IFUNC_VX_IMPL (strchrnul);
diff --git a/sysdeps/s390/multiarch/strchr-c.c b/sysdeps/s390/strchr-c.c
index 606cb56788..3d3579a1d3 100644
--- a/sysdeps/s390/multiarch/strchr-c.c
+++ b/sysdeps/s390/strchr-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 STRCHR  __strchr_c
-# undef weak_alias
-# ifdef SHARED
-#  undef libc_hidden_builtin_def
-#  define libc_hidden_builtin_def(name)				\
+#include <ifunc-strchr.h>
+
+#if HAVE_STRCHR_C
+# if HAVE_STRCHR_IFUNC
+#  define STRCHR STRCHR_C
+#  undef weak_alias
+#  if defined SHARED && IS_IN (libc)
+#   undef libc_hidden_builtin_def
+#   define libc_hidden_builtin_def(name)			\
      __hidden_ver1 (__strchr_c, __GI_strchr, __strchr_c);
-# endif /* SHARED */
+#  endif
+# endif
 
 # include <string/strchr.c>
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+#endif
diff --git a/sysdeps/s390/multiarch/strchr-vx.S b/sysdeps/s390/strchr-vx.S
index 6e744fb82f..6ffa06f78c 100644
--- a/sysdeps/s390/multiarch/strchr-vx.S
+++ b/sysdeps/s390/strchr-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-strchr.h>
+
+#if HAVE_STRCHR_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -36,7 +38,7 @@
    -v17=index of unequal
    -v18=replicated c
 */
-ENTRY(__strchr_vx)
+ENTRY(STRCHR_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -96,5 +98,15 @@ ENTRY(__strchr_vx)
 	clije	%r3,0,.Lcharacter /* Found zero and c is zero.  */
 	lghi	%r2,0		/* Return null if character not found.  */
 	br	%r14
-END(__strchr_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(STRCHR_Z13)
+
+# if ! HAVE_STRCHR_IFUNC
+strong_alias (STRCHR_Z13, strchr)
+weak_alias (strchr, index)
+# endif
+
+# if ! HAVE_STRCHR_C && defined SHARED && IS_IN (libc)
+strong_alias (STRCHR_Z13, __GI_strchr)
+# endif
+
+#endif /* HAVE_STRCHR_Z13  */
diff --git a/sysdeps/s390/multiarch/strchr.c b/sysdeps/s390/strchr.c
index 8aa33a51cc..a106c6106d 100644
--- a/sysdeps/s390/multiarch/strchr.c
+++ b/sysdeps/s390/strchr.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-strchr.h>
+
+#if HAVE_STRCHR_IFUNC
 # define strchr __redirect_strchr
 /* Omit the strchr inline definitions because it would redefine strchr.  */
 # define __NO_STRING_INLINES
@@ -24,9 +26,18 @@
 # undef strchr
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2_redirected (__redirect_strchr, __strchr, strchr)
-weak_alias (strchr, index)
+# if HAVE_STRCHR_C
+extern __typeof (__redirect_strchr) STRCHR_C attribute_hidden;
+# endif
 
-#else
-# include <string/strchr.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+# if HAVE_STRCHR_Z13
+extern __typeof (__redirect_strchr) STRCHR_Z13 attribute_hidden;
+# endif
+
+s390_libc_ifunc_expr (__redirect_strchr, strchr,
+		      (HAVE_STRCHR_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STRCHR_Z13
+		      : STRCHR_DEFAULT
+		      )
+weak_alias (strchr, index)
+#endif /* HAVE_STRCHR_IFUNC  */