xref: /illumos-gate/usr/src/uts/common/sys/linker_set.h (revision 0250c53ad267726f2438e3c6556199a0bbf588a2)
1 /*
2  * Copyright (c) 1999 John D. Polstra
3  * Copyright (c) 1999,2001 Peter Wemm <peter@FreeBSD.org>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #ifndef _SYS_LINKER_SET_H_
29 #define	_SYS_LINKER_SET_H_
30 
31 #include <sys/ccompile.h>
32 
33 /*
34  * The following macros are used to declare global sets of objects, which
35  * are collected by the linker into a `linker_set' as defined below.
36  * For ELF, this is done by constructing a separate segment for each set.
37  */
38 
39 #define	__MAKE_SET_CONST const
40 
41 #define	__CONCAT1(x, y)	x ## y
42 #define	__CONCAT(x, y)	__CONCAT1(x, y)
43 
44 #define	__STRING(x)	#x		/* stringify without expanding x */
45 #define	__XSTRING(x)	__STRING(x)	/* expand x, then stringify */
46 
47 #define	__GLOBL(sym)	__asm__(".globl " __XSTRING(sym))
48 #define	__WEAK(sym)	__asm__(".weak " __XSTRING(sym))
49 /*
50  * Private macros, not to be used outside this header file.
51  */
52 #define	__MAKE_SET(set, sym)				\
53 	__WEAK(__CONCAT(__start_set_, set));		\
54 	__WEAK(__CONCAT(__stop_set_, set));		\
55 	static void const * __MAKE_SET_CONST		\
56 	__set_##set##_sym_##sym __section("set_" #set)	\
57 	__used = &(sym)
58 
59 /*
60  * Public macros.
61  */
62 #define	TEXT_SET(set, sym)	__MAKE_SET(set, sym)
63 #define	DATA_SET(set, sym)	__MAKE_SET(set, sym)
64 #define	BSS_SET(set, sym)	__MAKE_SET(set, sym)
65 #define	ABS_SET(set, sym)	__MAKE_SET(set, sym)
66 #define	SET_ENTRY(set, sym)	__MAKE_SET(set, sym)
67 
68 /*
69  * Initialize before referring to a given linker set.
70  */
71 #define	SET_DECLARE(set, ptype)						\
72 	extern ptype __weak_symbol *__CONCAT(__start_set_, set);	\
73 	extern ptype __weak_symbol *__CONCAT(__stop_set_, set)
74 
75 #define	SET_BEGIN(set)							\
76 	(&__CONCAT(__start_set_, set))
77 #define	SET_LIMIT(set)							\
78 	(&__CONCAT(__stop_set_, set))
79 
80 /*
81  * Iterate over all the elements of a set.
82  *
83  * Sets always contain addresses of things, and "pvar" points to words
84  * containing those addresses.  Thus is must be declared as "type **pvar",
85  * and the address of each set item is obtained inside the loop by "*pvar".
86  */
87 #define	SET_FOREACH(pvar, set)						\
88 	for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
89 
90 #define	SET_ITEM(set, i)						\
91 	((SET_BEGIN(set))[i])
92 
93 /*
94  * Provide a count of the items in a set.
95  */
96 #define	SET_COUNT(set)							\
97 	(SET_LIMIT(set) - SET_BEGIN(set))
98 
99 #endif	/* _SYS_LINKER_SET_H_ */
100