When building with Zbb enabled, strcmp benefits from using orc.b in
find_zero_all(). This patch changes the build system such, that a
non-Zbb version as well as a Zbb version of this routine is built.
Further, a ifunc resolver is provided that selects the right routine
based on the outcome of extension probing via hwprobe().
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
---
sysdeps/riscv/multiarch/strcmp-generic.c | 26 +++++++++
sysdeps/riscv/multiarch/strcmp-zbb.c | 30 ++++++++++
.../unix/sysv/linux/riscv/multiarch/Makefile | 3 +
.../linux/riscv/multiarch/ifunc-impl-list.c | 4 ++
.../unix/sysv/linux/riscv/multiarch/strcmp.c | 57 +++++++++++++++++++
5 files changed, 120 insertions(+)
create mode 100644 sysdeps/riscv/multiarch/strcmp-generic.c
create mode 100644 sysdeps/riscv/multiarch/strcmp-zbb.c
create mode 100644 sysdeps/unix/sysv/linux/riscv/multiarch/strcmp.c
new file mode 100644
@@ -0,0 +1,26 @@
+/* Re-include the default strcmp implementation.
+ Copyright (C) 2024 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <string.h>
+
+#if IS_IN(libc)
+# define STRCMP __strcmp_generic
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(x)
+#endif
+#include <string/strcmp.c>
new file mode 100644
@@ -0,0 +1,30 @@
+/* Re-include the default strcmp implementation for Zbb.
+ Copyright (C) 2024 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <string.h>
+
+#if IS_IN(libc)
+# define STRCMP __strcmp_zbb
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(x)
+#endif
+/* Convince preprocessor to have Zbb instructions. */
+#ifndef __riscv_zbb
+# define __riscv_zbb
+#endif
+#include <string/strcmp.c>
@@ -12,6 +12,9 @@ sysdep_routines += \
strchrnul \
strchrnul-generic \
strchrnul-zbb \
+ strcmp \
+ strcmp-generic \
+ strcmp-zbb \
# sysdep_routines
CFLAGS-memcpy_noalignment.c += -mno-strict-align
@@ -68,5 +68,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_IMPL_ADD (array, i, strchrnul, has_zbb, __strchrnul_zbb)
IFUNC_IMPL_ADD (array, i, strchrnul, 1, __strchrnul_generic))
+ IFUNC_IMPL (i, name, strcmp,
+ IFUNC_IMPL_ADD (array, i, strcmp, has_zbb, __strcmp_zbb)
+ IFUNC_IMPL_ADD (array, i, strcmp, 1, __strcmp_generic))
+
return 0;
}
new file mode 100644
@@ -0,0 +1,57 @@
+/* Multiple versions of strcmp.
+ All versions must be listed in ifunc-impl-list.c.
+ Copyright (C) 2017-2024 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
+ <https://www.gnu.org/licenses/>. */
+
+#if IS_IN (libc)
+/* Redefine strcmp so that the compiler won't complain about the type
+ mismatch with the IFUNC selector in strong_alias, below. */
+# undef strcmp
+# define strcmp __redirect_strcmp
+# include <stdint.h>
+# include <string.h>
+# include <ifunc-init.h>
+# include <riscv-ifunc.h>
+# include <sys/hwprobe.h>
+
+extern __typeof (__redirect_strcmp) __libc_strcmp;
+
+extern __typeof (__redirect_strcmp) __strcmp_generic attribute_hidden;
+extern __typeof (__redirect_strcmp) __strcmp_zbb attribute_hidden;
+
+static inline __typeof (__redirect_strcmp) *
+select_strcmp_ifunc (uint64_t dl_hwcap, __riscv_hwprobe_t hwprobe_func)
+{
+ unsigned long long int v;
+ if (__riscv_hwprobe_one (hwprobe_func, RISCV_HWPROBE_KEY_IMA_EXT_0, &v) == 0
+ && (v & RISCV_HWPROBE_EXT_ZBB))
+ return __strcmp_zbb;
+
+ return __strcmp_generic;
+}
+
+riscv_libc_ifunc (__libc_strcmp, select_strcmp_ifunc);
+
+# undef strcmp
+strong_alias (__libc_strcmp, strcmp);
+# ifdef SHARED
+__hidden_ver1 (strcmp, __GI_strcmp, __redirect_strcmp)
+ __attribute__ ((visibility ("hidden"))) __attribute_copy__ (strcmp);
+# endif
+#else
+# include <string/strcmp.c>
+#endif