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-rw-r--r--sysdeps/aarch64/multiarch/Makefile3
-rw-r--r--sysdeps/aarch64/multiarch/ifunc-impl-list.c4
-rw-r--r--sysdeps/aarch64/multiarch/strlen.c41
-rw-r--r--sysdeps/aarch64/multiarch/strlen_asimd.S168
-rw-r--r--sysdeps/aarch64/multiarch/strlen_generic.S39
-rw-r--r--sysdeps/aarch64/strlen.S10
6 files changed, 261 insertions, 4 deletions
diff --git a/sysdeps/aarch64/multiarch/Makefile b/sysdeps/aarch64/multiarch/Makefile
index 57ffdf7238..b1a5f59fcd 100644
--- a/sysdeps/aarch64/multiarch/Makefile
+++ b/sysdeps/aarch64/multiarch/Makefile
@@ -1,4 +1,5 @@
 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
diff --git a/sysdeps/aarch64/multiarch/ifunc-impl-list.c b/sysdeps/aarch64/multiarch/ifunc-impl-list.c
index e55be80103..af446650a6 100644
--- a/sysdeps/aarch64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/aarch64/multiarch/ifunc-impl-list.c
@@ -53,5 +53,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      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;
 }
diff --git a/sysdeps/aarch64/multiarch/strlen.c b/sysdeps/aarch64/multiarch/strlen.c
new file mode 100644
index 0000000000..6c62d684c8
--- /dev/null
+++ b/sysdeps/aarch64/multiarch/strlen.c
@@ -0,0 +1,41 @@
+/* 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
diff --git a/sysdeps/aarch64/multiarch/strlen_asimd.S b/sysdeps/aarch64/multiarch/strlen_asimd.S
new file mode 100644
index 0000000000..ca37b931cb
--- /dev/null
+++ b/sysdeps/aarch64/multiarch/strlen_asimd.S
@@ -0,0 +1,168 @@
+/* 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)
diff --git a/sysdeps/aarch64/multiarch/strlen_generic.S b/sysdeps/aarch64/multiarch/strlen_generic.S
new file mode 100644
index 0000000000..4234948eba
--- /dev/null
+++ b/sysdeps/aarch64/multiarch/strlen_generic.S
@@ -0,0 +1,39 @@
+/* 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"
diff --git a/sysdeps/aarch64/strlen.S b/sysdeps/aarch64/strlen.S
index eb773ef532..521ebc3b75 100644
--- a/sysdeps/aarch64/strlen.S
+++ b/sysdeps/aarch64/strlen.S
@@ -23,6 +23,10 @@
  * 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.  */
@@ -84,7 +88,7 @@
 	   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
@@ -215,6 +219,6 @@ L(page_cross):
 	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)
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-07-16 15:36:10 +0000