linker_set.h revision 71766 
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: head/sys/sys/linker_set.h 71766 2001-01-29 01:46:50Z marcel $
27 */
28
29#ifndef _SYS_LINKER_SET_H_
30#define _SYS_LINKER_SET_H_
31
32/*
33 * The following macros are used to declare global sets of objects, which
34 * are collected by the linker into a `struct linker_set' as defined below.
35 * For ELF, this is done by constructing a separate segment for each set.
36 * For a.out, it is done automatically by the linker.
37 *
38 * In the MAKE_SET macros below, the lines:
39 *
40 *   static void const * const __set_##set##_sym_##sym = &sym;
41 *
42 * are present only to prevent the compiler from producing bogus
43 * warnings about unused symbols.
44 */
45#ifdef __ELF__
46
47#if defined(__alpha__) || defined(__ia64__)
48#define MAKE_SET(set, sym)						\
49	static void const * const __set_##set##_sym_##sym = &sym;	\
50	__asm(".section .set." #set ",\"aw\"");				\
51	__asm(".p2align 3");						\
52	__asm(".quad " #sym);						\
53	__asm(".previous")
54#else
55#define MAKE_SET(set, sym)						\
56	static void const * const __set_##set##_sym_##sym = &sym;	\
57	__asm(".section .set." #set ",\"aw\"");				\
58	__asm(".p2align 2");						\
59	__asm(".long " #sym);						\
60	__asm(".previous")
61#endif
62#define TEXT_SET(set, sym) MAKE_SET(set, sym)
63#define DATA_SET(set, sym) MAKE_SET(set, sym)
64
65#else
66
67/*
68 * NB: the constants defined below must match those defined in
69 * ld/ld.h.  Since their calculation requires arithmetic, we
70 * can't name them symbolically (e.g., 23 is N_SETT | N_EXT).
71 */
72#define MAKE_SET(set, sym, type) \
73	static void const * const __set_##set##_sym_##sym = &sym; \
74	__asm(".stabs \"_" #set "\", " #type ", 0, 0, _" #sym)
75#define TEXT_SET(set, sym) MAKE_SET(set, sym, 23)
76#define DATA_SET(set, sym) MAKE_SET(set, sym, 25)
77
78#endif
79
80struct linker_set {
81	int	ls_length;
82	void	*ls_items[1];		/* really ls_length of them,
83						 * trailing NULL */
84};
85
86#endif /* _SYS_LINKER_SET_H_ */
87