/*-
 * 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.
 *
 * $FreeBSD$
 */

#ifndef _SYS_LINKER_SET_H_
#define _SYS_LINKER_SET_H_

/*
 * 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.
 * For a.out, it is done automatically by the linker.
 */

#if defined(__ELF__)
/*
 * Private macros, not to be used outside this header file.
 */
/* this bit of h0h0magic brought to you by cpp */
#ifdef __GNUC__
#define	__GLOBL(sym)	__GLOBL2(sym)
#define	__GLOBL2(sym)	__asm(".globl " #sym)

#define __MAKE_SET(set, sym)						\
	__GLOBL(__CONCAT(__start_set_,set));				\
	__GLOBL(__CONCAT(__stop_set_,set));				\
	static void const * const __set_##set##_sym_##sym 		\
	__attribute__((__section__("set_" #set),__unused__)) = &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))

#else	/* __ELF__ */

/*
 * The old way.  This depends on GNU ld extensions that are not widely
 * available outside of the a.out format.
 *
 * NB: the constants defined below must match those defined in
 * ld/ld.h.  Since their calculation requires arithmetic, we
 * can't name them symbolically (e.g., 23 is N_SETT | N_EXT).
 *
 * In the __MAKE_SET macro below, the line:
 *   static void const * const __set_##set##_sym_##sym = &sym;
 * is present only to prevent the compiler from producing bogus
 * warnings about unused symbols.
 */
/* Private macros */
#ifdef __UNDERSCORES__
#define __MAKE_SET(set, sym, type) \
	static void const * const __set_##set##_sym_##sym = &sym;	\
	__asm(".stabs \"_" #set "\", " #type ", 0, 0, _" #sym)
#else
#define __MAKE_SET(set, sym, type) \
	static void const * const __set_##set##_sym_##sym = &sym;	\
	__asm(".stabs \"" #set "\", " #type ", 0, 0, " #sym)
#endif

/* Public Macros */
#define TEXT_SET(set, sym)	__MAKE_SET(set, sym, 23)
#define DATA_SET(set, sym)	__MAKE_SET(set, sym, 25)
#define BSS_SET(set, sym)	__MAKE_SET(set, sym, 27)
#define ABS_SET(set, sym)	__MAKE_SET(set, sym, 21)
#define SET_ENTRY(set, sym)	error error must provide text/data type

#define SET_DECLARE(set, ptype)						\
	extern struct  {						\
		int		ls_length;				\
		ptype		*ls_items[1];				\
	} set

#define SET_BEGIN(set)							\
	(&((set).ls_items[0]))
#define SET_LIMIT(set)							\
	(&((set).ls_items[(set).ls_length]))

#endif	/* __ELF__ */

/*
 * 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_ */