[PATCH v3 08/17] riscv: Add RVV strcat for multiarch and non-multiarch
Yao Zihong
zihong.plct@isrc.iscas.ac.cn
Tue Dec 30 15:30:35 GMT 2025
Co-authored-by: Hau Hsu <hau.hsu@sifive.com>
Co-authored-by: Jerry Shih <jerry.shih@sifive.com>
Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn>
---
sysdeps/riscv/multiarch/strcat-generic.c | 26 +++++++
sysdeps/riscv/multiarch/strcat-vector.S | 30 ++++++++
sysdeps/riscv/rvv/strcat.S | 75 +++++++++++++++++++
.../unix/sysv/linux/riscv/multiarch/Makefile | 3 +
.../linux/riscv/multiarch/ifunc-impl-list.c | 5 ++
.../unix/sysv/linux/riscv/multiarch/strcat.c | 56 ++++++++++++++
6 files changed, 195 insertions(+)
create mode 100644 sysdeps/riscv/multiarch/strcat-generic.c
create mode 100644 sysdeps/riscv/multiarch/strcat-vector.S
create mode 100644 sysdeps/riscv/rvv/strcat.S
create mode 100644 sysdeps/unix/sysv/linux/riscv/multiarch/strcat.c
diff --git a/sysdeps/riscv/multiarch/strcat-generic.c b/sysdeps/riscv/multiarch/strcat-generic.c
new file mode 100644
index 0000000000..60b4df8f8c
--- /dev/null
+++ b/sysdeps/riscv/multiarch/strcat-generic.c
@@ -0,0 +1,26 @@
+/* Re-include the default strcat implementation.
+ Copyright (C) 2025 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 STRCAT __strcat_generic
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(x)
+#endif
+#include <string/strcat.c>
diff --git a/sysdeps/riscv/multiarch/strcat-vector.S b/sysdeps/riscv/multiarch/strcat-vector.S
new file mode 100644
index 0000000000..c3efc2fd51
--- /dev/null
+++ b/sysdeps/riscv/multiarch/strcat-vector.S
@@ -0,0 +1,30 @@
+/* Re-include the RISC-V RVV based strcat implementation.
+ Copyright (C) 2025 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 IS_IN(libc)
+# define STRCAT __strcat_vector
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name)
+# undef libc_hidden_def
+# define libc_hidden_def(name)
+# undef weak_alias
+# define weak_alias(name, alias)
+# undef strong_alias
+# define strong_alias(name, alias)
+# include <sysdeps/riscv/rvv/strcat.S>
+#endif
diff --git a/sysdeps/riscv/rvv/strcat.S b/sysdeps/riscv/rvv/strcat.S
new file mode 100644
index 0000000000..a495c2cffa
--- /dev/null
+++ b/sysdeps/riscv/rvv/strcat.S
@@ -0,0 +1,75 @@
+/* RISC-V RVV based strcat.
+ Copyright (C) 2025 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/>. */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+
+#ifndef STRCAT
+# define STRCAT strcat
+#endif
+
+#define dst a0
+#define src a1
+#define dst_ptr a2
+
+#define ivl a3
+#define cur_vl a4
+#define active_elem_pos a5
+
+#define ELEM_LMUL_SETTING m1
+#define vmask1 v0
+#define vmask2 v1
+#define vstr1 v8
+#define vstr2 v16
+
+ENTRY (STRCAT)
+.option push
+.option arch, +v
+ mv dst_ptr, dst
+ /* Perform `strlen(dst)`. */
+L(strlen_loop):
+ vsetvli ivl, zero, e8, ELEM_LMUL_SETTING, ta, ma
+
+ vle8ff.v vstr1, (dst_ptr)
+ vmseq.vx vmask1, vstr1, zero
+ csrr cur_vl, vl
+ vfirst.m active_elem_pos, vmask1
+ add dst_ptr, dst_ptr, cur_vl
+ bltz active_elem_pos, L(strlen_loop)
+
+ sub dst_ptr, dst_ptr, cur_vl
+ add dst_ptr, dst_ptr, active_elem_pos
+
+ /* Perform `strcpy(dst, src)`. */
+L(strcpy_loop):
+ vsetvli ivl, zero, e8, ELEM_LMUL_SETTING, ta, ma
+
+ vle8ff.v vstr1, (src)
+ vmseq.vx vmask2, vstr1, zero
+ csrr cur_vl, vl
+ vfirst.m active_elem_pos, vmask2
+ vmsif.m vmask1, vmask2
+ add src, src, cur_vl
+ vse8.v vstr1, (dst_ptr), vmask1.t
+ add dst_ptr, dst_ptr, cur_vl
+ bltz active_elem_pos, L(strcpy_loop)
+
+ ret
+.option pop
+END (STRCAT)
+libc_hidden_builtin_def (strcat)
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
index 190e853e6e..b5449caf51 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
@@ -25,6 +25,9 @@ sysdep_routines += \
memset \
memset-generic \
memset-vector \
+ strcat \
+ strcat-generic \
+ strcat-vector \
# sysdep_routines
CFLAGS-memcpy_noalignment.c += -mno-strict-align
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c b/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
index d66025e10d..449dc39480 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
@@ -85,5 +85,10 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
__memrchr_vector)
IFUNC_IMPL_ADD (array, i, memrchr, 1, __memrchr_generic))
+ IFUNC_IMPL (i, name, strcat,
+ IFUNC_IMPL_ADD (array, i, strcat, rvv_enabled,
+ __strcat_vector)
+ IFUNC_IMPL_ADD (array, i, strcat, 1, __strcat_generic))
+
return 0;
}
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/strcat.c b/sysdeps/unix/sysv/linux/riscv/multiarch/strcat.c
new file mode 100644
index 0000000000..e4c3fdd8cf
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/strcat.c
@@ -0,0 +1,56 @@
+/* Multiple versions of strcat.
+ All versions must be listed in ifunc-impl-list.c.
+ Copyright (C) 2025 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 strcat so that the compiler won't complain about the type
+ mismatch with the IFUNC selector in strong_alias, below. */
+# undef strcat
+# define strcat __redirect_strcat
+# include <stdint.h>
+# include <string.h>
+# include <ifunc-init.h>
+# include <riscv-ifunc.h>
+# include <sys/hwprobe.h>
+
+extern __typeof (__redirect_strcat) __libc_strcat;
+
+extern __typeof (__redirect_strcat) __strcat_generic attribute_hidden;
+extern __typeof (__redirect_strcat) __strcat_vector attribute_hidden;
+
+static inline __typeof (__redirect_strcat) *
+select_strcat_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_IMA_V) == RISCV_HWPROBE_IMA_V)
+ return __strcat_vector;
+ return __strcat_generic;
+}
+
+riscv_libc_ifunc (__libc_strcat, select_strcat_ifunc);
+
+# undef strcat
+strong_alias (__libc_strcat, strcat);
+# ifdef SHARED
+__hidden_ver1 (strcat, __GI_strcat, __redirect_strcat)
+ __attribute__ ((visibility ("hidden"))) __attribute_copy__ (strcat);
+# endif
+#else
+# include <string/strcat.c>
+#endif
--
2.47.2
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