sys/sys/linker_set.h

   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         static void const * const __set_##set##_sym_##sym               \
  65         __section("set_" #set) __used = &sym
  66
  67 #define TEXT_SET(set, sym) __MAKE_SET(set, sym)
  68 #define DATA_SET(set, sym) __MAKE_SET(set, sym)
  69 #define BSS_SET(set, sym) __MAKE_SET(set, sym)
  70 #define ABS_SET(set, sym) __MAKE_SET(set, sym)
  71 #define SET_ENTRY(set, sym) __MAKE_SET(set, sym)
  72
  73 #define SET_DECLARE(set, ptype)                         \
  74         extern ptype *__CONCAT(__start_set_,set);       \
  75         extern ptype *__CONCAT(__stop_set_,set)
  76
  77 #define SET_BEGIN(set)          (&__CONCAT(__start_set_,set))
  78 #define SET_LIMIT(set)          (&__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_ */