bsd/sys/linker_set.h

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*-
  31  * Copyright (c) 1999 John D. Polstra
  32  * All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  * 1. Redistributions of source code must retain the above copyright
  38  *    notice, this list of conditions and the following disclaimer.
  39  * 2. Redistributions in binary form must reproduce the above copyright
  40  *    notice, this list of conditions and the following disclaimer in the
  41  *    documentation and/or other materials provided with the distribution.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  *
  55  */
  56
  57 #ifndef _SYS_LINKER_SET_H_
  58 #define _SYS_LINKER_SET_H_
  59
  60 #include <sys/appleapiopts.h>
  61
  62 #if !defined(KERNEL) || defined(__APPLE_API_PRIVATE)
  63 /*
  64  * The following macros are used to declare global sets of objects, which
  65  * are collected by the linker into a `struct linker_set' as defined below.
  66  * For ELF, this is done by constructing a separate segment for each set.
  67  * For a.out, it is done automatically by the linker.
  68  */
  69
  70 #define __ELF__
  71 #ifdef __ELF__
  72
  73 #define MAKE_SET(seg, set, sym)                                         \
  74         static void const * const __set_##set##_sym_##sym = &sym;       \
  75         __asm(".section  seg, " #set "");       \
  76         __asm(".long " #sym);
  77
  78 /*      __asm(".previous") */
  79
  80
  81 #define TEXT_SET(set, sym) MAKE_SET(__TEXT, set, sym)
  82 #define DATA_SET(set, sym) MAKE_SET(__DATA, set, sym)
  83 #define BSS_SET(set, sym)  MAKE_SET(__BSS,  set, sym)
  84 #define ABS_SET(set, sym)  MAKE_SET(__ABS,  set, sym)
  85
  86 #else
  87
  88 /*
  89  * NB: the constants defined below must match those defined in
  90  * nlist.h.  Since their calculation requires arithmetic, we
  91  * can't name them symbolically (e.g., 7 is N_DATA | N_EXT).
  92  */
  93 #define MAKE_SET(set, sym, type) \
  94         static void const * const __set_##set##_sym_##sym = &sym; \
  95         __asm(".stabs \"_" #set "\", " #type ", 0, 0, _" #sym)
  96
  97 #define TEXT_SET(set, sym) MAKE_SET(set, sym, 5)
  98 #define DATA_SET(set, sym) MAKE_SET(set, sym, 7)
  99 #define BSS_SET(set, sym)  MAKE_SET(set, sym, 9)
 100 #define ABS_SET(set, sym)  MAKE_SET(set, sym, 3)
 101
 102 #endif
 103
 104 struct linker_set {
 105         int             ls_length;
 106         const void      *ls_items[1];           /* really ls_length of them,
 107                                                  * trailing NULL */
 108 };
 109 #endif /* !KERNEL || __APPLE_API_PRIVATE */
 110
 111 #endif /* _SYS_LINKER_SET_H_ */
 112