[v2,14/15] RISC-V: Add Zbb optimized strlen as ifunc

Message ID 20240527111900.1060546-15-christoph.muellner@vrull.eu
State New
Headers
Series RISC-V: Add Zbb-optimized string routines as ifuncs |

Checks

Context Check Description
redhat-pt-bot/TryBot-apply_patch success Patch applied to master at the time it was sent
linaro-tcwg-bot/tcwg_glibc_build--master-arm success Testing passed
linaro-tcwg-bot/tcwg_glibc_check--master-arm success Testing passed
linaro-tcwg-bot/tcwg_glibc_build--master-aarch64 success Testing passed
linaro-tcwg-bot/tcwg_glibc_check--master-aarch64 success Testing passed

Commit Message

Christoph Müllner May 27, 2024, 11:18 a.m. UTC
  When building with Zbb enabled, strlen 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/strlen-generic.c      | 24 ++++++++
 sysdeps/riscv/multiarch/strlen-zbb.c          | 23 ++++++++
 .../unix/sysv/linux/riscv/multiarch/Makefile  |  3 +
 .../linux/riscv/multiarch/ifunc-impl-list.c   |  6 ++
 .../unix/sysv/linux/riscv/multiarch/strlen.c  | 59 +++++++++++++++++++
 5 files changed, 115 insertions(+)
 create mode 100644 sysdeps/riscv/multiarch/strlen-generic.c
 create mode 100644 sysdeps/riscv/multiarch/strlen-zbb.c
 create mode 100644 sysdeps/unix/sysv/linux/riscv/multiarch/strlen.c
  

Patch

diff --git a/sysdeps/riscv/multiarch/strlen-generic.c b/sysdeps/riscv/multiarch/strlen-generic.c
new file mode 100644
index 0000000000..e2d59bd4ef
--- /dev/null
+++ b/sysdeps/riscv/multiarch/strlen-generic.c
@@ -0,0 +1,24 @@ 
+/* Re-include the default strlen 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 STRLEN __strlen_generic
+#endif
+#include <string/strlen.c>
diff --git a/sysdeps/riscv/multiarch/strlen-zbb.c b/sysdeps/riscv/multiarch/strlen-zbb.c
new file mode 100644
index 0000000000..3be9e78556
--- /dev/null
+++ b/sysdeps/riscv/multiarch/strlen-zbb.c
@@ -0,0 +1,23 @@ 
+/* Re-include the default strlen 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 STRLEN __strlen_zbb
+#include <string/strlen.c>
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
index 69c4dd2d07..e48ca11149 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
@@ -11,6 +11,8 @@  sysdep_routines += \
   strchrnul-generic \
   strcmp \
   strcmp-generic \
+  strlen \
+  strlen-generic \
   # sysdep_routines
 
 ifeq ($(have-fattribute-zbb-support),yes)
@@ -19,6 +21,7 @@  sysdep_routines += \
   memrchr-zbb \
   strchrnul-zbb \
   strcmp-zbb \
+  strlen-zbb \
   # Zbb sysdep_routines
 endif
 
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 c761807a7a..9b4ae40941 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
@@ -84,5 +84,11 @@  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 #endif
 	      IFUNC_IMPL_ADD (array, i, strcmp, 1, __strcmp_generic))
 
+  IFUNC_IMPL (i, name, strlen,
+#if HAVE_RISCV_FATTRIBUTE_ZBB
+	      IFUNC_IMPL_ADD (array, i, strlen, has_zbb, __strlen_zbb)
+#endif
+	      IFUNC_IMPL_ADD (array, i, strlen, 1, __strlen_generic))
+
   return 0;
 }
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/strlen.c b/sysdeps/unix/sysv/linux/riscv/multiarch/strlen.c
new file mode 100644
index 0000000000..dec274af18
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/strlen.c
@@ -0,0 +1,59 @@ 
+/* Multiple versions of strlen.
+   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 strlen so that the compiler won't complain about the type
+   mismatch with the IFUNC selector in strong_alias, below.  */
+# undef strlen
+# define strlen __redirect_strlen
+# include <stdint.h>
+# include <string.h>
+# include <ifunc-init.h>
+# include <riscv-ifunc.h>
+# include <sys/hwprobe.h>
+
+extern __typeof (__redirect_strlen) __libc_strlen;
+
+extern __typeof (__redirect_strlen) __strlen_generic attribute_hidden;
+extern __typeof (__redirect_strlen) __strlen_zbb attribute_hidden;
+
+static inline __typeof (__redirect_strlen) *
+select_strlen_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 __strlen_zbb;
+#endif
+
+  return __strlen_generic;
+}
+
+riscv_libc_ifunc (__libc_strlen, select_strlen_ifunc);
+
+# undef strlen
+strong_alias (__libc_strlen, strlen);
+# ifdef SHARED
+__hidden_ver1 (strlen, __GI_strlen, __redirect_strlen)
+  __attribute__ ((visibility ("hidden"))) __attribute_copy__ (strlen);
+# endif
+#else
+# include <string/strlen.c>
+#endif