+2018-08-15 Siddhesh Poyarekar <siddhesh@sourceware.org>
+
+ * sysdeps/aarch64/strlen.S (__strlen): Rename to STRLEN.
+ [!STRLEN](STRLEN): Set to __strlen.
+ * sysdeps/aarch64/multiarch/strlen.c: New file.
+ * sysdeps/aarch64/multiarch/strlen_generic.S: Likewise.
+ * sysdeps/aarch64/multiarch/strlen_asimd.S: Likewise.
+ * sysdeps/aarch64/multiarch/ifunc-impl-list.c
+ (__libc_ifunc_impl_list): Add strlen.
+ * sysdeps/aarch64/multiarch/Makefile (sysdep_routines): Add
+ strlen_generic and strlen_asimd.
+
2018-08-15 Wilco Dijkstra <wdijkstr@arm.com>
* sysdeps/ieee754/flt-32/e_lgammaf_r.c (sin_pif): Use __sinf/__cosf.
ifeq ($(subdir),string)
sysdep_routines += memcpy_generic memcpy_thunderx memcpy_thunderx2 \
- memcpy_falkor memmove_falkor memset_generic memset_falkor
+ memcpy_falkor memmove_falkor memset_generic memset_falkor \
+ strlen_generic strlen_asimd
endif
IFUNC_IMPL_ADD (array, i, memset, (zva_size == 64), __memset_falkor)
IFUNC_IMPL_ADD (array, i, memset, 1, __memset_generic))
+ IFUNC_IMPL (i, name, strlen,
+ IFUNC_IMPL_ADD (array, i, strlen, 1, __strlen_asimd)
+ IFUNC_IMPL_ADD (array, i, strlen, 1, __strlen_generic))
+
return i;
}
--- /dev/null
+/* Multiple versions of strlen. AARCH64 version.
+ Copyright (C) 2018 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/>. */
+
+/* Define multiple versions only for the definition in libc. */
+
+#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 <string.h>
+# include <init-arch.h>
+
+#define USE_ASIMD_STRLEN() IS_FALKOR (midr)
+
+extern __typeof (__redirect_strlen) __strlen;
+
+extern __typeof (__redirect_strlen) __strlen_generic attribute_hidden;
+extern __typeof (__redirect_strlen) __strlen_asimd attribute_hidden;
+
+libc_ifunc (__strlen,
+ (USE_ASIMD_STRLEN () ? __strlen_asimd : __strlen_generic));
+
+# undef strlen
+strong_alias (__strlen, strlen);
+#endif
--- /dev/null
+/* Strlen implementation that uses ASIMD instructions for load and NULL checks.
+ Copyright (C) 2018 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>
+
+/* Assumptions:
+
+ ARMv8-a, AArch64, ASIMD, unaligned accesses, min page size 4k. */
+
+/* To test the page crossing code path more thoroughly, compile with
+ -DTEST_PAGE_CROSS - this will force all calls through the slower
+ entry path. This option is not intended for production use. */
+
+/* Arguments and results. */
+#define srcin x0
+#define len x0
+
+/* Locals and temporaries. */
+#define src x1
+#define data1 x2
+#define data2 x3
+#define has_nul1 x4
+#define has_nul2 x5
+#define tmp1 x4
+#define tmp2 x5
+#define tmp3 x6
+#define tmp4 x7
+#define zeroones x8
+#define dataq q2
+#define datav v2
+#define datab2 b3
+#define dataq2 q3
+#define datav2 v3
+
+#ifdef TEST_PAGE_CROSS
+# define MIN_PAGE_SIZE 16
+#else
+# define MIN_PAGE_SIZE 4096
+#endif
+
+ /* Since strings are short on average, we check the first 16 bytes
+ of the string for a NUL character. In order to do an unaligned load
+ safely we have to do a page cross check first. If there is a NUL
+ byte we calculate the length from the 2 8-byte words using
+ conditional select to reduce branch mispredictions (it is unlikely
+ strlen_asimd will be repeatedly called on strings with the same
+ length).
+
+ If the string is longer than 16 bytes, we align src so don't need
+ further page cross checks, and process 16 bytes per iteration.
+
+ If the page cross check fails, we read 16 bytes from an aligned
+ address, remove any characters before the string, and continue
+ in the main loop using aligned loads. Since strings crossing a
+ page in the first 16 bytes are rare (probability of
+ 16/MIN_PAGE_SIZE ~= 0.4%), this case does not need to be optimized.
+
+ AArch64 systems have a minimum page size of 4k. We don't bother
+ checking for larger page sizes - the cost of setting up the correct
+ page size is just not worth the extra gain from a small reduction in
+ the cases taking the slow path. Note that we only care about
+ whether the first fetch, which may be misaligned, crosses a page
+ boundary. */
+
+ENTRY_ALIGN (__strlen_asimd, 6)
+ DELOUSE (0)
+ DELOUSE (1)
+ and tmp1, srcin, MIN_PAGE_SIZE - 1
+ cmp tmp1, MIN_PAGE_SIZE - 16
+ b.gt L(page_cross)
+ ldr dataq, [srcin]
+#ifdef __AARCH64EB__
+ rev64 datav.16b, datav.16b
+#endif
+
+ /* Get the minimum value and keep going if it is not zero. */
+ uminv datab2, datav.16b
+ mov tmp1, datav2.d[0]
+ cbnz tmp1, L(main_loop_entry)
+
+ cmeq datav.16b, datav.16b, #0
+ mov data1, datav.d[0]
+ mov data2, datav.d[1]
+ cmp data1, 0
+ csel data1, data1, data2, ne
+ mov len, 8
+ rev data1, data1
+ clz tmp1, data1
+ csel len, xzr, len, ne
+ add len, len, tmp1, lsr 3
+ ret
+
+L(main_loop_entry):
+ bic src, srcin, 15
+
+L(main_loop):
+ ldr dataq, [src, 16]!
+L(page_cross_entry):
+ /* Get the minimum value and keep going if it is not zero. */
+ uminv datab2, datav.16b
+ mov tmp1, datav2.d[0]
+ cbnz tmp1, L(main_loop)
+
+L(tail):
+#ifdef __AARCH64EB__
+ rev64 datav.16b, datav.16b
+#endif
+ /* Set te NULL byte as 0xff and the rest as 0x00, move the data into a
+ pair of scalars and then compute the length from the earliest NULL
+ byte. */
+ cmeq datav.16b, datav.16b, #0
+ mov data1, datav.d[0]
+ mov data2, datav.d[1]
+ cmp data1, 0
+ csel data1, data1, data2, ne
+ sub len, src, srcin
+ rev data1, data1
+ add tmp2, len, 8
+ clz tmp1, data1
+ csel len, len, tmp2, ne
+ add len, len, tmp1, lsr 3
+ ret
+
+ /* Load 16 bytes from [srcin & ~15] and force the bytes that precede
+ srcin to 0xff, so we ignore any NUL bytes before the string.
+ Then continue in the aligned loop. */
+L(page_cross):
+ mov tmp3, 63
+ bic src, srcin, 15
+ and tmp1, srcin, 7
+ ands tmp2, srcin, 8
+ ldr dataq, [src]
+ lsl tmp1, tmp1, 3
+ csel tmp2, tmp2, tmp1, eq
+ csel tmp1, tmp1, tmp3, eq
+ mov tmp4, -1
+#ifdef __AARCH64EB__
+ /* Big-endian. Early bytes are at MSB. */
+ lsr tmp1, tmp4, tmp1
+ lsr tmp2, tmp4, tmp2
+#else
+ /* Little-endian. Early bytes are at LSB. */
+ lsl tmp1, tmp4, tmp1
+ lsl tmp2, tmp4, tmp2
+#endif
+ mov datav2.d[0], tmp1
+ mov datav2.d[1], tmp2
+ orn datav.16b, datav.16b, datav2.16b
+ b L(page_cross_entry)
+END (__strlen_asimd)
+weak_alias (__strlen_asimd, strlen_asimd)
+libc_hidden_builtin_def (strlen_asimd)
--- /dev/null
+/* A Generic Optimized strlen implementation for AARCH64.
+ Copyright (C) 2018 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/>. */
+
+/* The actual strlen code is in ../strlen.S. If we are building libc this file
+ defines __strlen_generic. Otherwise the include of ../strlen.S will define
+ the normal __strlen entry points. */
+
+#include <sysdep.h>
+
+#if IS_IN (libc)
+
+# define STRLEN __strlen_generic
+
+/* Do not hide the generic version of strlen, we use it internally. */
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name)
+
+# ifdef SHARED
+/* It doesn't make sense to send libc-internal strlen calls through a PLT. */
+ .globl __GI_strlen; __GI_strlen = __strlen_generic
+# endif
+#endif
+
+#include "../strlen.S"
* ARMv8-a, AArch64, unaligned accesses, min page size 4k.
*/
+#ifndef STRLEN
+# define STRLEN __strlen
+#endif
+
/* To test the page crossing code path more thoroughly, compile with
-DTEST_PAGE_CROSS - this will force all calls through the slower
entry path. This option is not intended for production use. */
whether the first fetch, which may be misaligned, crosses a page
boundary. */
-ENTRY_ALIGN (__strlen, 6)
+ENTRY_ALIGN (STRLEN, 6)
DELOUSE (0)
DELOUSE (1)
and tmp1, srcin, MIN_PAGE_SIZE - 1
csel data1, data1, tmp4, eq
csel data2, data2, tmp2, eq
b L(page_cross_entry)
-END (__strlen)
-weak_alias (__strlen, strlen)
+END (STRLEN)
+weak_alias (STRLEN, strlen)
libc_hidden_builtin_def (strlen)
projects / thirdparty / glibc.git / commitdiff
