bsd/sys/linker_set.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*-
  23  * Copyright (c) 1999 John D. Polstra
  24  * All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  *
  35  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  36  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  37  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  38  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  39  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  40  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  41  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  42  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  43  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  44  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  45  * SUCH DAMAGE.
  46  *
  47  */
  48
  49 #ifndef _SYS_LINKER_SET_H_
  50 #define _SYS_LINKER_SET_H_
  51
  52 /*
  53  * The following macros are used to declare global sets of objects, which
  54  * are collected by the linker into a `struct linker_set' as defined below.
  55  * For ELF, this is done by constructing a separate segment for each set.
  56  * For a.out, it is done automatically by the linker.
  57  */
  58
  59 #define __ELF__
  60 #ifdef __ELF__
  61
  62 #define MAKE_SET(seg, set, sym)                                         \
  63         static void const * const __set_##set##_sym_##sym = &sym;       \
  64         __asm(".section  seg, " #set "");       \
  65         __asm(".long " #sym);
  66
  67 /*      __asm(".previous") */
  68
  69
  70 #define TEXT_SET(set, sym) MAKE_SET(__TEXT, set, sym)
  71 #define DATA_SET(set, sym) MAKE_SET(__DATA, set, sym)
  72 #define BSS_SET(set, sym)  MAKE_SET(__BSS,  set, sym)
  73 #define ABS_SET(set, sym)  MAKE_SET(__ABS,  set, sym)
  74
  75 #else
  76
  77 /*
  78  * NB: the constants defined below must match those defined in
  79  * nlist.h.  Since their calculation requires arithmetic, we
  80  * can't name them symbolically (e.g., 7 is N_DATA | N_EXT).
  81  */
  82 #define MAKE_SET(set, sym, type) \
  83         static void const * const __set_##set##_sym_##sym = &sym; \
  84         __asm(".stabs \"_" #set "\", " #type ", 0, 0, _" #sym)
  85
  86 #define TEXT_SET(set, sym) MAKE_SET(set, sym, 5)
  87 #define DATA_SET(set, sym) MAKE_SET(set, sym, 7)
  88 #define BSS_SET(set, sym)  MAKE_SET(set, sym, 9)
  89 #define ABS_SET(set, sym)  MAKE_SET(set, sym, 3)
  90
  91 #endif
  92
  93 struct linker_set {
  94         int             ls_length;
  95         const void      *ls_items[1];           /* really ls_length of them,
  96                                                  * trailing NULL */
  97 };
  98
  99 #endif /* _SYS_LINKER_SET_H_ */
 100