1/* This file is part of the GNU C Library.
2 Copyright (C) 2008-2017 Free Software Foundation, Inc.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18#ifdef __ASSEMBLER__
19# include <cpu-features.h>
20#else
21# include <ldsodefs.h>
22#endif
23
24/* These macros are used to implement ifunc selection in C. To implement
25 an ifunc function, foo, which returns the address of __foo_sse2 or
26 __foo_avx2:
27
28 #define foo __redirect_foo
29 #define __foo __redirect___foo
30 #include <foo.h>
31 #undef foo
32 #undef __foo
33 #define SYMBOL_NAME foo
34 #include <init-arch.h>
35
36 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
37 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
38
39 static inline void *
40 foo_selector (void)
41 {
42 if (use AVX2)
43 return OPTIMIZE (avx2);
44
45 return OPTIMIZE (sse2);
46 }
47
48 libc_ifunc_redirected (__redirect_foo, foo, foo_selector ());
49
50*/
51
52#define PASTER1(x,y) x##_##y
53#define EVALUATOR1(x,y) PASTER1 (x,y)
54#define PASTER2(x,y) __##x##_##y
55#define EVALUATOR2(x,y) PASTER2 (x,y)
56
57/* Basically set '__redirect_<symbol>' to use as type definition,
58 '__<symbol>_<variant>' as the optimized implementation and
59 '<symbol>_ifunc_selector' as the IFUNC selector. */
60#define REDIRECT_NAME EVALUATOR1 (__redirect, SYMBOL_NAME)
61#define OPTIMIZE(name) EVALUATOR2 (SYMBOL_NAME, name)
62#define IFUNC_SELECTOR EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
63
64#ifndef __x86_64__
65/* Due to the reordering and the other nifty extensions in i686, it is
66 not really good to use heavily i586 optimized code on an i686. It's
67 better to use i486 code if it isn't an i586. */
68# if MINIMUM_ISA == 686
69# define USE_I586 0
70# define USE_I686 1
71# else
72# define USE_I586 (HAS_ARCH_FEATURE (I586) && !HAS_ARCH_FEATURE (I686))
73# define USE_I686 HAS_ARCH_FEATURE (I686)
74# endif
75#endif
76