Use IFUNC on x86-64 memset

1 files changed, 74 insertions, 0 deletions

diff --git a/sysdeps/x86_64/multiarch/memset.S b/sysdeps/x86_64/multiarch/memset.S
new file mode 100644
index 0000000000..a8d0e9ea22
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memset.S
@@ -0,0 +1,74 @@
+/* Multiple versions of memset
+   Copyright (C) 2010 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+#include <init-arch.h>
+
+/* Define multiple versions only for the definition in lib.  */
+#ifndef NOT_IN_libc
+ENTRY(memset)
+	.type	memset, @gnu_indirect_function
+	cmpl	$0, __cpu_features+KIND_OFFSET(%rip)
+	jne	1f
+	call	__init_cpu_features
+1:	leaq	__memset_x86_64(%rip), %rax
+	testl	$bit_Prefer_SSE_for_memop, __cpu_features+FEATURE_OFFSET+index_Prefer_SSE_for_memop(%rip)
+	jz	2f
+	leaq	__memset_sse2(%rip), %rax
+2:	ret
+END(memset)
+
+# define USE_SSE2 1
+
+# undef ENTRY
+# define ENTRY(name) \
+	.type __memset_sse2, @function; \
+	.globl __memset_sse2; \
+	.p2align 4; \
+	__memset_sse2: cfi_startproc; \
+	CALL_MCOUNT
+# undef END
+# define END(name) \
+	cfi_endproc; .size __memset_sse2, .-__memset_sse2
+
+# undef ENTRY_CHK
+# define ENTRY_CHK(name) \
+	.type __memset_chk_sse2, @function; \
+	.globl __memset_chk_sse2; \
+	.p2align 4; \
+	__memset_chk_sse2: cfi_startproc; \
+	CALL_MCOUNT
+# undef END_CHK
+# define END_CHK(name) \
+	cfi_endproc; .size __memset_chk_sse2, .-__memset_chk_sse2
+
+# ifdef SHARED
+#  undef libc_hidden_builtin_def
+/* It doesn't make sense to send libc-internal memset calls through a PLT.
+   The speedup we get from using GPR instruction is likely eaten away
+   by the indirect call in the PLT.  */
+#  define libc_hidden_builtin_def(name) \
+	.globl __GI_memset; __GI_memset = __memset_sse2
+# endif
+
+# undef strong_alias
+# define strong_alias(original, alias)
+#endif
+
+#include "../memset.S"