new file mode 100644
@@ -0,0 +1,26 @@
+/* Re-include the default strncmp 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 STRNCMP __strncmp_generic
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(x)
+#endif
+#include <string/strncmp.c>
new file mode 100644
@@ -0,0 +1,25 @@
+/* Re-include the default strncmp 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/>. */
+
+/* Build with Zbb enabled. */
+#define __CODEGEN_ATTRIBUTES __attribute__((target("arch=+zbb")))
+#define USE_ZBB_ORCB 1
+#define STRNCMP __strncmp_zbb
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(x)
+#include <string/strncmp.c>
@@ -13,6 +13,8 @@ sysdep_routines += \
strcmp-generic \
strlen \
strlen-generic \
+ strncmp \
+ strncmp-generic \
# sysdep_routines
ifeq ($(have-fattribute-zbb-support),yes)
@@ -22,6 +24,7 @@ sysdep_routines += \
strchrnul-zbb \
strcmp-zbb \
strlen-zbb \
+ strncmp-zbb \
# Zbb sysdep_routines
endif
@@ -90,5 +90,11 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
#endif
IFUNC_IMPL_ADD (array, i, strlen, 1, __strlen_generic))
+ IFUNC_IMPL (i, name, strncmp,
+#if HAVE_RISCV_FATTRIBUTE_ZBB
+ IFUNC_IMPL_ADD (array, i, strncmp, has_zbb, __strncmp_zbb)
+#endif
+ IFUNC_IMPL_ADD (array, i, strncmp, 1, __strncmp_generic))
+
return 0;
}
new file mode 100644
@@ -0,0 +1,59 @@
+/* Multiple versions of strncmp.
+ 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 strncmp so that the compiler won't complain about the type
+ mismatch with the IFUNC selector in strong_alias, below. */
+# undef strncmp
+# define strncmp __redirect_strncmp
+# include <stdint.h>
+# include <string.h>
+# include <ifunc-init.h>
+# include <riscv-ifunc.h>
+# include <sys/hwprobe.h>
+
+extern __typeof (__redirect_strncmp) __libc_strncmp;
+
+extern __typeof (__redirect_strncmp) __strncmp_generic attribute_hidden;
+extern __typeof (__redirect_strncmp) __strncmp_zbb attribute_hidden;
+
+static inline __typeof (__redirect_strncmp) *
+select_strncmp_ifunc (uint64_t dl_hwcap, __riscv_hwprobe_t hwprobe_func)
+{
+#if HAVE_RISCV_FATTRIBUTE_ZBB
+ 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 __strncmp_zbb;
+#endif
+
+ return __strncmp_generic;
+}
+
+riscv_libc_ifunc (__libc_strncmp, select_strncmp_ifunc);
+
+# undef strncmp
+strong_alias (__libc_strncmp, strncmp);
+# ifdef SHARED
+__hidden_ver1 (strncmp, __GI_strncmp, __redirect_strncmp)
+ __attribute__ ((visibility ("hidden"))) __attribute_copy__ (strncmp);
+# endif
+#else
+# include <string/strncmp.c>
+#endif
When building with Zbb enabled, strncmp 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/strncmp-generic.c | 26 ++++++++ sysdeps/riscv/multiarch/strncmp-zbb.c | 25 ++++++++ .../unix/sysv/linux/riscv/multiarch/Makefile | 3 + .../linux/riscv/multiarch/ifunc-impl-list.c | 6 ++ .../unix/sysv/linux/riscv/multiarch/strncmp.c | 59 +++++++++++++++++++ 5 files changed, 119 insertions(+) create mode 100644 sysdeps/riscv/multiarch/strncmp-generic.c create mode 100644 sysdeps/riscv/multiarch/strncmp-zbb.c create mode 100644 sysdeps/unix/sysv/linux/riscv/multiarch/strncmp.c