xref: /dragonfly/sys/sys/linker_set.h (revision cfd1aba3)
1 /*-
2  * Copyright (c) 1999 John D. Polstra
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD: src/sys/sys/linker_set.h,v 1.4.2.1 2000/08/02 21:52:20 peter Exp $
27  * $DragonFly: src/sys/sys/linker_set.h,v 1.4 2004/08/27 12:08:41 joerg Exp $
28  */
29 
30 #ifndef _SYS_LINKER_SET_H_
31 #define _SYS_LINKER_SET_H_
32 
33 #ifndef _SYS_CDEFS_H_
34 #include <sys/cdefs.h>
35 #endif
36 
37 /*
38  * The following macros are used to declare global sets of objects, which
39  * are collected by the linker into a `struct linker_set' as defined below.
40  * For ELF, this is done by constructing a separate segment for each set.
41  *
42  * In the __MAKE_SET macros below, the lines:
43  *
44  *   static void const * const __set_##set##_sym_##sym = &sym;
45  *
46  * are present only to prevent the compiler from producing bogus
47  * warnings about unused symbols.
48  */
49 #ifndef __ELF__
50 #error only ELF is supported
51 #endif
52 
53 #if 0
54 
55 #define __MAKE_SET(set, sym)						\
56 	static void const * const __set_##set##_sym_##sym = &sym;	\
57 	__asm(".section set_" #set ",\"aw\"");				\
58 	__asm(".long " #sym);						\
59 	__asm(".previous")
60 
61 #endif
62 
63 #define __MAKE_SET(set, sym)						\
64 	__GLOBL(__CONCAT(__start_set_,set));				\
65 	__GLOBL(__CONCAT(__stop_set_,set));				\
66 	static void const * const __set_##set##_sym_##sym		\
67 	__section("set_" #set) __used = &sym
68 
69 #define TEXT_SET(set, sym) __MAKE_SET(set, sym)
70 #define DATA_SET(set, sym) __MAKE_SET(set, sym)
71 #define BSS_SET(set, sym) __MAKE_SET(set, sym)
72 #define ABS_SET(set, sym) __MAKE_SET(set, sym)
73 #define SET_ENTRY(set, sym) __MAKE_SET(set, sym)
74 
75 #define SET_DECLARE(set, ptype)				\
76 	extern ptype *__CONCAT(__start_set_,set);	\
77 	extern ptype *__CONCAT(__stop_set_,set)
78 
79 #define SET_BEGIN(set)		(&__CONCAT(__start_set_,set))
80 #define SET_LIMIT(set)		(&__CONCAT(__stop_set_,set))
81 
82 /*
83  * Iterate over all the elements of a set.
84  *
85  * Sets always contain addresses of things, and "pvar" points to words
86  * containing those addresses.  Thus is must be declared as "type **pvar",
87  * and the address of each set item is obtained inside the loop by "*pvar".
88  */
89 #define SET_FOREACH(pvar, set)				\
90 	for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
91 
92 #define SET_ITEM(set, i)				\
93 	((SET_BEGIN(set))[i])
94 
95 /*
96  * Provide a count of the items in a set.
97  */
98 #define SET_COUNT(set)					\
99 	(SET_LIMIT(set) - SET_BEGIN(set))
100 
101 #endif /* _SYS_LINKER_SET_H_ */
102