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9cd30491dd
These macros are used to implement ifunc selection in C. To implement
an ifunc function, foo, which returns the address of __foo_sse2 or
__foo_avx2:
__foo_avx2:
#define foo __redirect_foo
#define __foo __redirect___foo
#include <foo.h>
#undef foo
#undef __foo
#define SYMBOL_NAME foo
#include <init-arch.h>
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
static inline void *
foo_selector (void)
{
if (use AVX2)
return OPTIMIZE (avx2);
return OPTIMIZE (sse2);
}
libc_ifunc_redirected (__redirect_foo, foo, foo_selector ());
* sysdeps/x86/init-arch.h (PASTER1): New.
(EVALUATOR1): Likewise.
(PASTER2): Likewise.
(EVALUATOR2): Likewise.
(REDIRECT_NAME): Likewise.
(OPTIMIZE): Likewise.
(IFUNC_SELECTOR): Likewise.
76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/* This file is part of the GNU C Library.
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Copyright (C) 2008-2017 Free Software Foundation, Inc.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifdef __ASSEMBLER__
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# include <cpu-features.h>
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#else
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# include <ldsodefs.h>
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#endif
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/* These macros are used to implement ifunc selection in C. To implement
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an ifunc function, foo, which returns the address of __foo_sse2 or
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__foo_avx2:
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#define foo __redirect_foo
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#define __foo __redirect___foo
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#include <foo.h>
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#undef foo
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#undef __foo
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#define SYMBOL_NAME foo
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#include <init-arch.h>
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extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
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extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
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static inline void *
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foo_selector (void)
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{
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if (use AVX2)
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return OPTIMIZE (avx2);
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return OPTIMIZE (sse2);
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}
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libc_ifunc_redirected (__redirect_foo, foo, foo_selector ());
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*/
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#define PASTER1(x,y) x##_##y
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#define EVALUATOR1(x,y) PASTER1 (x,y)
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#define PASTER2(x,y) __##x##_##y
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#define EVALUATOR2(x,y) PASTER2 (x,y)
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/* Basically set '__redirect_<symbol>' to use as type definition,
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'__<symbol>_<variant>' as the optimized implementation and
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'<symbol>_ifunc_selector' as the IFUNC selector. */
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#define REDIRECT_NAME EVALUATOR1 (__redirect, SYMBOL_NAME)
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#define OPTIMIZE(name) EVALUATOR2 (SYMBOL_NAME, name)
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#define IFUNC_SELECTOR EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
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#ifndef __x86_64__
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/* Due to the reordering and the other nifty extensions in i686, it is
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not really good to use heavily i586 optimized code on an i686. It's
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better to use i486 code if it isn't an i586. */
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# if MINIMUM_ISA == 686
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# define USE_I586 0
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# define USE_I686 1
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# else
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# define USE_I586 (HAS_ARCH_FEATURE (I586) && !HAS_ARCH_FEATURE (I686))
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# define USE_I686 HAS_ARCH_FEATURE (I686)
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# endif
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#endif
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