[PATCH 21/56] S390: Refactor stpncpy ifunc handling.

[Stefan Liebler <stli at linux dot ibm dot com>]

The ifunc handling for stpncpy 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 stpncpy variants.
	* sysdeps/s390/Makefile (sysdep_routines): Add stpncpy variants.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Refactor ifunc handling for stpncpy.
	* sysdeps/s390/multiarch/stpncpy-c.c: Move to ...
	* sysdeps/s390/stpncpy-c.c: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/stpncpy-vx.S: Move to ...
	* sysdeps/s390/stpncpy-vx.S: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/stpncpy.c: Move to ...
	* sysdeps/s390/stpncpy.c: ... here and adjust ifunc handling.
	* sysdeps/s390/ifunc-stpncpy.h: New file.
---
 sysdeps/s390/Makefile                     |  3 +-
 sysdeps/s390/ifunc-stpncpy.h              | 52 +++++++++++++++++++++++
 sysdeps/s390/multiarch/Makefile           |  3 +-
 sysdeps/s390/multiarch/ifunc-impl-list.c  | 14 +++++-
 sysdeps/s390/{multiarch => }/stpncpy-c.c  | 21 +++++----
 sysdeps/s390/{multiarch => }/stpncpy-vx.S | 19 +++++++--
 sysdeps/s390/{multiarch => }/stpncpy.c    | 23 +++++++---
 7 files changed, 113 insertions(+), 22 deletions(-)
 create mode 100644 sysdeps/s390/ifunc-stpncpy.h
 rename sysdeps/s390/{multiarch => }/stpncpy-c.c (74%)
 rename sysdeps/s390/{multiarch => }/stpncpy-vx.S (95%)
 rename sysdeps/s390/{multiarch => }/stpncpy.c (70%)

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index 7cadf7ceba..f02afd4d02 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -64,5 +64,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   strnlen strnlen-vx strnlen-c \
 		   strcpy strcpy-vx strcpy-z900 \
 		   stpcpy stpcpy-vx stpcpy-c \
-		   strncpy strncpy-vx strncpy-z900
+		   strncpy strncpy-vx strncpy-z900 \
+		   stpncpy stpncpy-vx stpncpy-c
 endif
diff --git a/sysdeps/s390/ifunc-stpncpy.h b/sysdeps/s390/ifunc-stpncpy.h
new file mode 100644
index 0000000000..46e57334e8
--- /dev/null
+++ b/sysdeps/s390/ifunc-stpncpy.h
@@ -0,0 +1,52 @@
+/* stpncpy 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_STPNCPY_IFUNC	1
+#else
+# define HAVE_STPNCPY_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STPNCPY_IFUNC_AND_VX_SUPPORT HAVE_STPNCPY_IFUNC
+#else
+# define HAVE_STPNCPY_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STPNCPY_DEFAULT	STPNCPY_Z13
+# define HAVE_STPNCPY_C		0
+# define HAVE_STPNCPY_Z13	1
+#else
+# define STPNCPY_DEFAULT	STPNCPY_C
+# define HAVE_STPNCPY_C		1
+# define HAVE_STPNCPY_Z13	HAVE_STPNCPY_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STPNCPY_C
+# define STPNCPY_C		__stpncpy_c
+#else
+# define STPNCPY_C		NULL
+#endif
+
+#if HAVE_STPNCPY_Z13
+# define STPNCPY_Z13		__stpncpy_vx
+#else
+# define STPNCPY_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index c5189b556c..3d97d21da1 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += stpncpy stpncpy-vx stpncpy-c \
-		   strcat strcat-vx strcat-c \
+sysdep_routines += strcat strcat-vx strcat-c \
 		   strncat strncat-vx strncat-c \
 		   strcmp strcmp-vx \
 		   strncmp strncmp-vx strncmp-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index d598fc5c22..021e9f247f 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -31,6 +31,7 @@
 #include <ifunc-strcpy.h>
 #include <ifunc-stpcpy.h>
 #include <ifunc-strncpy.h>
+#include <ifunc-stpncpy.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -229,6 +230,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STRNCPY_IFUNC  */
 
+#if HAVE_STPNCPY_IFUNC
+    IFUNC_IMPL (i, name, stpncpy,
+# if HAVE_STPNCPY_Z13
+		IFUNC_IMPL_ADD (array, i, stpncpy,
+				dl_hwcap & HWCAP_S390_VX, STPNCPY_Z13)
+# endif
+# if HAVE_STPNCPY_C
+		IFUNC_IMPL_ADD (array, i, stpncpy, 1, STPNCPY_C)
+# endif
+		)
+#endif /* HAVE_STPNCPY_IFUNC  */
+
 
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
@@ -248,7 +261,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcsncpy);
 
-  IFUNC_VX_IMPL (stpncpy);
   IFUNC_VX_IMPL (wcpncpy);
 
   IFUNC_VX_IMPL (strcat);
diff --git a/sysdeps/s390/multiarch/stpncpy-c.c b/sysdeps/s390/stpncpy-c.c
similarity index 74%
rename from sysdeps/s390/multiarch/stpncpy-c.c
rename to sysdeps/s390/stpncpy-c.c
index 45e50aa9e7..e5d1ae8675 100644
--- a/sysdeps/s390/multiarch/stpncpy-c.c
+++ b/sysdeps/s390/stpncpy-c.c
@@ -16,13 +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 STPNCPY  __stpncpy_c
-# ifdef SHARED
-#  undef libc_hidden_def
-#  define libc_hidden_def(name)  \
-     __hidden_ver1 (__stpncpy_c, __GI___stpncpy, __stpncpy_c);
-# endif /* SHARED */
+#include <ifunc-stpncpy.h>
+
+#if HAVE_STPNCPY_C
+# if HAVE_STPNCPY_IFUNC
+#  define STPNCPY STPNCPY_C
+
+#  if defined SHARED && IS_IN (libc)
+#   undef libc_hidden_def
+#   define libc_hidden_def(name)				\
+  __hidden_ver1 (__stpncpy_c, __GI___stpncpy, __stpncpy_c);
+#  endif
+# endif
 
 # include <string/stpncpy.c>
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+#endif
diff --git a/sysdeps/s390/multiarch/stpncpy-vx.S b/sysdeps/s390/stpncpy-vx.S
similarity index 95%
rename from sysdeps/s390/multiarch/stpncpy-vx.S
rename to sysdeps/s390/stpncpy-vx.S
index 922bd7a355..3dccc10be3 100644
--- a/sysdeps/s390/multiarch/stpncpy-vx.S
+++ b/sysdeps/s390/stpncpy-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-stpncpy.h>
+
+#if HAVE_STPNCPY_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -38,7 +40,7 @@
    -%r6 = loaded bytes
    -%r7 = border, tmp
 */
-ENTRY(__stpncpy_vx)
+ENTRY(STPNCPY_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -196,5 +198,14 @@ ENTRY(__stpncpy_vx)
 
 	vl	%v16,0(%r5,%r3)	/* Load s.  */
 	j	.Llt64
-END(__stpncpy_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(STPNCPY_Z13)
+
+# if ! HAVE_STPNCPY_IFUNC
+strong_alias (STPNCPY_Z13, __stpncpy)
+weak_alias (__stpncpy, stpncpy)
+# endif
+
+# if ! HAVE_STPNCPY_C && defined SHARED && IS_IN (libc)
+strong_alias (STPNCPY_Z13, __GI___stpncpy)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/stpncpy.c b/sysdeps/s390/stpncpy.c
similarity index 70%
rename from sysdeps/s390/multiarch/stpncpy.c
rename to sysdeps/s390/stpncpy.c
index f7f9d51a50..250dc68ed1 100644
--- a/sysdeps/s390/multiarch/stpncpy.c
+++ b/sysdeps/s390/stpncpy.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-stpncpy.h>
+
+#if HAVE_STPNCPY_IFUNC
 # define stpncpy __redirect_stpncpy
 # define __stpncpy __redirect___stpncpy
 # include <string.h>
@@ -24,9 +26,18 @@
 # undef __stpncpy
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc_redirected (__redirect___stpncpy, __stpncpy)
-weak_alias (__stpncpy, stpncpy)
+# if HAVE_STPNCPY_C
+extern __typeof (__redirect_stpncpy) STPNCPY_C attribute_hidden;
+# endif
 
-#else
-# include <string/stpncpy.c>
-#endif  /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+# if HAVE_STPNCPY_Z13
+extern __typeof (__redirect_stpncpy) STPNCPY_Z13 attribute_hidden;
+# endif
+
+s390_libc_ifunc_expr (__redirect___stpncpy, __stpncpy,
+		      (HAVE_STPNCPY_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STPNCPY_Z13
+		      : STPNCPY_DEFAULT
+		      )
+weak_alias (__stpncpy, stpncpy)
+#endif
-- 
2.17.0