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  */
  28
  29 #ifndef _SYS_LINKER_SET_H_
  30 #define _SYS_LINKER_SET_H_
  31
  32 #ifndef _SYS_CDEFS_H_
  33 #include <sys/cdefs.h>
  34 #endif
  35
  36 /*
  37  * The following macros are used to declare global sets of objects, which
  38  * are collected by the linker into a `struct linker_set' as defined below.
  39  * For ELF, this is done by constructing a separate segment for each set.
  40  *
  41  * In the __MAKE_SET macros below, the lines:
  42  *
  43  *   static void const * const __set_##set##_sym_##sym = &sym;
  44  *
  45  * are present only to prevent the compiler from producing bogus
  46  * warnings about unused symbols.
  47  */
  48 #ifndef __ELF__
  49 #error only ELF is supported
  50 #endif
  51
  52 #if 0
  53
  54 #define __MAKE_SET(set, sym)                                            \
  55         static void const * const __set_##set##_sym_##sym = &sym;       \
  56         __asm(".section set_" #set ",\"aw\"");                          \
  57         __asm(".long " #sym);                                           \
  58         __asm(".previous")
  59
  60 #endif
  61
  62 #define __MAKE_SET(set, sym)                                            \
  63         __GLOBL(__CONCAT(__start_set_,set));                            \
  64         __GLOBL(__CONCAT(__stop_set_,set));                             \
  65         static void const * const __set_##set##_sym_##sym               \
  66         __section("set_" #set) __used = &(sym)
  67
  68 #define TEXT_SET(set, sym) __MAKE_SET(set, sym)
  69 #define DATA_SET(set, sym) __MAKE_SET(set, sym)
  70 #define BSS_SET(set, sym) __MAKE_SET(set, sym)
  71 #define ABS_SET(set, sym) __MAKE_SET(set, sym)
  72 #define SET_ENTRY(set, sym) __MAKE_SET(set, sym)
  73
  74 #define SET_DECLARE(set, ptype)                         \
  75         extern ptype *__CONCAT(__start_set_,set);       \
  76         extern ptype *__CONCAT(__stop_set_,set)
  77 #define SET_DECLARE_WEAK(set, ptype)                            \
  78         extern ptype __weak_symbol *__CONCAT(__start_set_,set); \
  79         extern ptype __weak_symbol *__CONCAT(__stop_set_,set)
  80
  81 #define SET_BEGIN(set)          (&__CONCAT(__start_set_,set))
  82 #define SET_LIMIT(set)          (&__CONCAT(__stop_set_,set))
  83
  84 /*
  85  * Iterate over all the elements of a set.
  86  *
  87  * Sets always contain addresses of things, and "pvar" points to words
  88  * containing those addresses.  Thus is must be declared as "type **pvar",
  89  * and the address of each set item is obtained inside the loop by "*pvar".
  90  */
  91 #define SET_FOREACH(pvar, set)                          \
  92         for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
  93
  94 #define SET_ITEM(set, i)                                \
  95         ((SET_BEGIN(set))[i])
  96
  97 /*
  98  * Provide a count of the items in a set.
  99  */
 100 #define SET_COUNT(set)                                  \
 101         (SET_LIMIT(set) - SET_BEGIN(set))
 102
 103 #endif /* _SYS_LINKER_SET_H_ */