[v2,13/15] RISC-V: Add Zbb optimized strcmp as ifunc

Message ID 20240527111900.1060546-14-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, 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      | 24 ++++++++
 sysdeps/riscv/multiarch/strcmp-zbb.c          | 23 ++++++++
 .../unix/sysv/linux/riscv/multiarch/Makefile  |  3 +
 .../linux/riscv/multiarch/ifunc-impl-list.c   |  6 ++
 .../unix/sysv/linux/riscv/multiarch/strcmp.c  | 59 +++++++++++++++++++
 5 files changed, 115 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
  

Patch

diff --git a/sysdeps/riscv/multiarch/strcmp-generic.c b/sysdeps/riscv/multiarch/strcmp-generic.c
new file mode 100644
index 0000000000..ef9fb9eb46
--- /dev/null
+++ b/sysdeps/riscv/multiarch/strcmp-generic.c
@@ -0,0 +1,24 @@ 
+/* 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
+#endif
+#include <string/strcmp.c>
diff --git a/sysdeps/riscv/multiarch/strcmp-zbb.c b/sysdeps/riscv/multiarch/strcmp-zbb.c
new file mode 100644
index 0000000000..86a2996358
--- /dev/null
+++ b/sysdeps/riscv/multiarch/strcmp-zbb.c
@@ -0,0 +1,23 @@ 
+/* 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/>.  */
+
+/* Build with Zbb enabled.  */
+#define __CODEGEN_ATTRIBUTES __attribute__((target("arch=+zbb")))
+#define USE_ZBB_ORCB 1
+#define STRCMP __strcmp_zbb
+#include <string/strcmp.c>
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
index 5a442905b5..69c4dd2d07 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
@@ -9,6 +9,8 @@  sysdep_routines += \
   memrchr-generic \
   strchrnul \
   strchrnul-generic \
+  strcmp \
+  strcmp-generic \
   # sysdep_routines
 
 ifeq ($(have-fattribute-zbb-support),yes)
@@ -16,6 +18,7 @@  sysdep_routines += \
   memchr-zbb \
   memrchr-zbb \
   strchrnul-zbb \
+  strcmp-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 7a769122ec..c761807a7a 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
@@ -78,5 +78,11 @@  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 #endif
 	      IFUNC_IMPL_ADD (array, i, strchrnul, 1, __strchrnul_generic))
 
+  IFUNC_IMPL (i, name, strcmp,
+#if HAVE_RISCV_FATTRIBUTE_ZBB
+	      IFUNC_IMPL_ADD (array, i, strcmp, has_zbb, __strcmp_zbb)
+#endif
+	      IFUNC_IMPL_ADD (array, i, strcmp, 1, __strcmp_generic))
+
   return 0;
 }
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/strcmp.c b/sysdeps/unix/sysv/linux/riscv/multiarch/strcmp.c
new file mode 100644
index 0000000000..f32f87a8e9
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/strcmp.c
@@ -0,0 +1,59 @@ 
+/* 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)
+{
+#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 __strcmp_zbb;
+#endif
+
+  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