[PATCH 24/56] S390: Refactor strcmp ifunc handling.

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

The ifunc handling for strcmp 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.

Note: The fallback s390-32/s390-64 ifunc variants with clst instruction
are now moved to the unified strcmp-z900.S file which can be used for
31/64bit. The s390-32/s390-64 files multiarch/strcmp.c and strcmp.S
are deleted.

ChangeLog:

	* sysdeps/s390/multiarch/Makefile
	(sysdep_routines): Remove strcmp variants.
	* sysdeps/s390/Makefile (sysdep_routines): Add strcmp variants.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Refactor ifunc handling for strcmp.
	* sysdeps/s390/multiarch/strcmp-vx.S: Move to ...
	* sysdeps/s390/strcmp-vx.S: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/strcmp.c: Move to ...
	* sysdeps/s390/strcmp.c: ... here and adjust ifunc handling.
	* sysdeps/s390/ifunc-strcmp.h: New file.
	* sysdeps/s390/s390-64/strcmp.S: Move to ...
	* sysdeps/s390/strcmp-z900.S: ... here and adjust to be usable
	for 31/64bit and ifunc handling.
	* sysdeps/s390/s390-32/multiarch/strcmp.c: Delete file.
	* sysdeps/s390/s390-64/multiarch/strcmp.c: Likewise.
	* sysdeps/s390/s390-32/strcmp.S: Likewise.
---
 sysdeps/s390/Makefile                         |  3 +-
 sysdeps/s390/ifunc-strcmp.h                   | 52 +++++++++++++++++++
 sysdeps/s390/multiarch/Makefile               |  3 +-
 sysdeps/s390/multiarch/ifunc-impl-list.c      | 14 ++++-
 sysdeps/s390/s390-32/multiarch/strcmp.c       | 21 --------
 sysdeps/s390/s390-32/strcmp.S                 | 41 ---------------
 sysdeps/s390/s390-64/multiarch/strcmp.c       | 21 --------
 sysdeps/s390/{multiarch => }/strcmp-vx.S      | 19 ++++---
 .../s390/{s390-64/strcmp.S => strcmp-z900.S}  | 32 +++++++++---
 sysdeps/s390/{multiarch => }/strcmp.c         | 17 +++++-
 10 files changed, 119 insertions(+), 104 deletions(-)
 create mode 100644 sysdeps/s390/ifunc-strcmp.h
 delete mode 100644 sysdeps/s390/s390-32/multiarch/strcmp.c
 delete mode 100644 sysdeps/s390/s390-32/strcmp.S
 delete mode 100644 sysdeps/s390/s390-64/multiarch/strcmp.c
 rename sysdeps/s390/{multiarch => }/strcmp-vx.S (90%)
 rename sysdeps/s390/{s390-64/strcmp.S => strcmp-z900.S} (70%)
 rename sysdeps/s390/{multiarch => }/strcmp.c (71%)

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index ec0fb8c2ad..9e7d5625c9 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -67,5 +67,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   strncpy strncpy-vx strncpy-z900 \
 		   stpncpy stpncpy-vx stpncpy-c \
 		   strcat strcat-vx strcat-c \
-		   strncat strncat-vx strncat-c
+		   strncat strncat-vx strncat-c \
+		   strcmp strcmp-vx strcmp-z900
 endif
diff --git a/sysdeps/s390/ifunc-strcmp.h b/sysdeps/s390/ifunc-strcmp.h
new file mode 100644
index 0000000000..86ffe686ad
--- /dev/null
+++ b/sysdeps/s390/ifunc-strcmp.h
@@ -0,0 +1,52 @@
+/* strcmp 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_STRCMP_IFUNC	1
+#else
+# define HAVE_STRCMP_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STRCMP_IFUNC_AND_VX_SUPPORT HAVE_STRCMP_IFUNC
+#else
+# define HAVE_STRCMP_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STRCMP_DEFAULT		STRCMP_Z13
+# define HAVE_STRCMP_Z900_G5	0
+# define HAVE_STRCMP_Z13	1
+#else
+# define STRCMP_DEFAULT		STRCMP_Z900_G5
+# define HAVE_STRCMP_Z900_G5	1
+# define HAVE_STRCMP_Z13	HAVE_STRCMP_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STRCMP_Z900_G5
+# define STRCMP_Z900_G5		__strcmp_default
+#else
+# define STRCMP_Z900_G5		NULL
+#endif
+
+#if HAVE_STRCMP_Z13
+# define STRCMP_Z13		__strcmp_vx
+#else
+# define STRCMP_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 24be3eac51..97421a4996 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += strcmp strcmp-vx \
-		   strncmp strncmp-vx strncmp-c \
+sysdep_routines += strncmp strncmp-vx strncmp-c \
 		   strchr strchr-vx strchr-c \
 		   strchrnul strchrnul-vx strchrnul-c \
 		   strrchr strrchr-vx strrchr-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 3abcaf08e0..44637c431b 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -34,6 +34,7 @@
 #include <ifunc-stpncpy.h>
 #include <ifunc-strcat.h>
 #include <ifunc-strncat.h>
+#include <ifunc-strcmp.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -268,6 +269,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STRNCAT_IFUNC  */
 
+#if HAVE_STRCMP_IFUNC
+    IFUNC_IMPL (i, name, strcmp,
+# if HAVE_STRCMP_Z13
+		IFUNC_IMPL_ADD (array, i, strcmp,
+				dl_hwcap & HWCAP_S390_VX, STRCMP_Z13)
+# endif
+# if HAVE_STRCMP_Z900_G5
+		IFUNC_IMPL_ADD (array, i, strcmp, 1, STRCMP_Z900_G5)
+# endif
+		)
+#endif /* HAVE_STRCMP_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -292,7 +305,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcsncat);
 
-  IFUNC_VX_IMPL (strcmp);
   IFUNC_VX_IMPL (wcscmp);
 
   IFUNC_VX_IMPL (strncmp);
diff --git a/sysdeps/s390/s390-32/multiarch/strcmp.c b/sysdeps/s390/s390-32/multiarch/strcmp.c
deleted file mode 100644
index d06b0f3436..0000000000
--- a/sysdeps/s390/s390-32/multiarch/strcmp.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/* Multiple versions of strcmp.
-   Copyright (C) 2015-2018 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/>.  */
-
-/* This wrapper-file is needed, because otherwise file
-   sysdeps/s390/s390-[32|64]/strcmp.S will be used.  */
-#include <sysdeps/s390/multiarch/strcmp.c>
diff --git a/sysdeps/s390/s390-32/strcmp.S b/sysdeps/s390/s390-32/strcmp.S
deleted file mode 100644
index 3cf3f239fd..0000000000
--- a/sysdeps/s390/s390-32/strcmp.S
+++ /dev/null
@@ -1,41 +0,0 @@
-/* strcmp - compare two string.  S/390 version.
-   This file is part of the GNU C Library.
-   Copyright (C) 2001-2018 Free Software Foundation, Inc.
-   Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
-
-   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/>.  */
-
-/* INPUT PARAMETERS
-     %r2 = address of string 1
-     %r3 = address of string 2.  */
-
-#include "sysdep.h"
-#include "asm-syntax.h"
-
-	.text
-ENTRY(strcmp)
-        slr   %r0,%r0
-0:	clst  %r2,%r3
-	jo    0b
-	jp    1f
-	jm    2f
-	slr   %r2,%r2
-	br    %r14
-1:	lhi   %r2,1
-	br    %r14
-2:	lhi   %r2,-1
-	br    %r14
-END(strcmp)
-libc_hidden_builtin_def (strcmp)
diff --git a/sysdeps/s390/s390-64/multiarch/strcmp.c b/sysdeps/s390/s390-64/multiarch/strcmp.c
deleted file mode 100644
index d06b0f3436..0000000000
--- a/sysdeps/s390/s390-64/multiarch/strcmp.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/* Multiple versions of strcmp.
-   Copyright (C) 2015-2018 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/>.  */
-
-/* This wrapper-file is needed, because otherwise file
-   sysdeps/s390/s390-[32|64]/strcmp.S will be used.  */
-#include <sysdeps/s390/multiarch/strcmp.c>
diff --git a/sysdeps/s390/multiarch/strcmp-vx.S b/sysdeps/s390/strcmp-vx.S
similarity index 90%
rename from sysdeps/s390/multiarch/strcmp-vx.S
rename to sysdeps/s390/strcmp-vx.S
index bcaeb564d4..801ad9d32b 100644
--- a/sysdeps/s390/multiarch/strcmp-vx.S
+++ b/sysdeps/s390/strcmp-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-strcmp.h>
+#if HAVE_STRCMP_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -36,7 +37,7 @@
    -v17=part of s2
    -v18=index of unequal
 */
-ENTRY(__strcmp_vx)
+ENTRY(STRCMP_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -106,11 +107,13 @@ ENTRY(__strcmp_vx)
 .Lend_equal:
 	lghi	%r2,0
 	br	%r14
-END(__strcmp_vx)
+END(STRCMP_Z13)
 
-# define strcmp __strcmp_c
-# undef libc_hidden_builtin_def
-# define libc_hidden_builtin_def(name) strong_alias(__strcmp_c, __GI_strcmp)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+# if ! HAVE_STRCMP_IFUNC
+strong_alias (STRCMP_Z13, strcmp)
+# endif
 
-#include <strcmp.S>
+# if ! HAVE_STRCMP_Z900_G5 && defined SHARED && IS_IN (libc)
+strong_alias (STRCMP_Z13, __GI_strcmp)
+# endif
+#endif
diff --git a/sysdeps/s390/s390-64/strcmp.S b/sysdeps/s390/strcmp-z900.S
similarity index 70%
rename from sysdeps/s390/s390-64/strcmp.S
rename to sysdeps/s390/strcmp-z900.S
index 6cf1addd8b..67b3c8b2e5 100644
--- a/sysdeps/s390/s390-64/strcmp.S
+++ b/sysdeps/s390/strcmp-z900.S
@@ -21,21 +21,39 @@
      %r2 = address of string 1
      %r3 = address of string 2.  */
 
+#include <ifunc-strcmp.h>
 #include "sysdep.h"
 #include "asm-syntax.h"
 
+#if HAVE_STRCMP_Z900_G5
+# if defined __s390x__
+#  define SLGR	slgr
+#  define LGHI	lghi
+# else
+#  define SLGR	slr
+#  define LGHI	lhi
+# endif /* ! defined __s390x__  */
+
 	.text
-ENTRY(strcmp)
-        slr   %r0,%r0
+ENTRY(STRCMP_Z900_G5)
+	SLGR   %r0,%r0
 0:	clst  %r2,%r3
 	jo    0b
 	jp    1f
 	jm    2f
-	slgr  %r2,%r2
+	SLGR  %r2,%r2
 	br    %r14
-1:	lghi  %r2,1
+1:	LGHI  %r2,1
 	br    %r14
-2:	lghi  %r2,-1
+2:	LGHI  %r2,-1
 	br    %r14
-END(strcmp)
-libc_hidden_builtin_def (strcmp)
+END(STRCMP_Z900_G5)
+
+# if ! HAVE_STRCMP_IFUNC
+strong_alias (STRCMP_Z900_G5, strcmp)
+# endif
+
+# if defined SHARED && IS_IN (libc)
+strong_alias (STRCMP_Z900_G5, __GI_strcmp)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/strcmp.c b/sysdeps/s390/strcmp.c
similarity index 71%
rename from sysdeps/s390/multiarch/strcmp.c
rename to sysdeps/s390/strcmp.c
index 7c8b17b304..9efa30acaf 100644
--- a/sysdeps/s390/multiarch/strcmp.c
+++ b/sysdeps/s390/strcmp.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-strcmp.h>
+
+#if HAVE_STRCMP_IFUNC
 # define strcmp __redirect_strcmp
 /* Omit the strcmp inline definitions because it would redefine strcmp.  */
 # define __NO_STRING_INLINES
@@ -24,6 +26,17 @@
 # include <ifunc-resolve.h>
 # undef strcmp
 
-s390_vx_libc_ifunc2_redirected (__redirect_strcmp, __strcmp, strcmp)
+# if HAVE_STRCMP_Z900_G5
+extern __typeof (__redirect_strcmp) STRCMP_Z900_G5 attribute_hidden;
+# endif
+
+# if HAVE_STRCMP_Z13
+extern __typeof (__redirect_strcmp) STRCMP_Z13 attribute_hidden;
+# endif
 
+s390_libc_ifunc_expr (__redirect_strcmp, strcmp,
+		      (HAVE_STRCMP_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STRCMP_Z13
+		      : STRCMP_DEFAULT
+		      )
 #endif
-- 
2.17.0