linker_set.h

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/*-
 * Copyright (c) 1999 John D. Polstra
 * Copyright (c) 1999,2001 Peter Wemm <peter@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/sys/linker_set.h,v 1.13 2002/09/23 06:11:29 peter Exp $
 */

#ifndef _SYS_LINKER_SET_H_
#define _SYS_LINKER_SET_H_

/* FIXME: These macros should not be here
 * BSD has them macros in sys/cdefs.h
 * older rtems had them in rtems/bsd/sys/cdefs.h
 * newlib has some of them in sys/cdefs.h
 */

#if defined(__rtems__)
#ifndef __used
#define __used          __attribute__((__used__))
#endif
#ifndef __CONCAT
#define __CONCAT1(x,y)  x ## y
#define __CONCAT(x,y)   __CONCAT1(x,y)
#endif
#endif

/*
 * The following macros are used to declare global sets of objects, which
 * are collected by the linker into a `linker_set' as defined below.
 * For ELF, this is done by constructing a separate segment for each set.
 */

/*
 * Private macros, not to be used outside this header file.
 */
#ifdef __GNUC__
#define __MAKE_SET(set, sym)                                            \
        static void const * const __set_##set##_sym_##sym               \
        __attribute((section("set_" #set))) __used = &sym
#else /* !__GNUC__ */
#ifndef lint
#error "This file needs to be compiled by GCC or lint"
#endif /* lint */
#define __MAKE_SET(set, sym)    extern void const * const (__set_##set##_sym_##sym)
#endif /* __GNUC__ */

/*
 * Public macros.
 */
#define TEXT_SET(set, sym)      __MAKE_SET(set, sym)
#define DATA_SET(set, sym)      __MAKE_SET(set, sym)
#define BSS_SET(set, sym)       __MAKE_SET(set, sym)
#define ABS_SET(set, sym)       __MAKE_SET(set, sym)
#define SET_ENTRY(set, sym)     __MAKE_SET(set, sym)

/*
 * Initialize before referring to a give linker set
 */
#define SET_DECLARE(set, ptype)                                         \
        extern ptype *__CONCAT(__start_set_,set)[];                     \
        extern ptype *__CONCAT(__stop_set_,set)[]

#define SET_BEGIN(set)                                                  \
        (__CONCAT(__start_set_,set))
#define SET_LIMIT(set)                                                  \
        (__CONCAT(__stop_set_,set))

/*
 * Iterate over all the elements of a set.
 *
 * Sets always contain addresses of things, and "pvar" points to words
 * containing those addresses.  Thus is must be declared as "type **pvar",
 * and the address of each set item is obtained inside the loop by "*pvar".
 */
#define SET_FOREACH(pvar, set)                                          \
        for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)

#define SET_ITEM(set, i)                                                \
        ((SET_BEGIN(set))[i])

/*
 * Provide a count of the items in a set.
 */
#define SET_COUNT(set)                                                  \
        (SET_LIMIT(set) - SET_BEGIN(set))

#endif  /* _SYS_LINKER_SET_H_ */