gcc/config/m32r/initfini.c

   1 /* .init/.fini section handling + C++ global constructor/destructor handling.
   2    This file is based on crtstuff.c, sol2-crti.asm, sol2-crtn.asm.
   3
   4 Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 In addition to the permissions in the GNU General Public License, the
  14 Free Software Foundation gives you unlimited permission to link the
  15 compiled version of this file into combinations with other programs,
  16 and to distribute those combinations without any restriction coming
  17 from the use of this file.  (The General Public License restrictions
  18 do apply in other respects; for example, they cover modification of
  19 the file, and distribution when not linked into a combine
  20 executable.)
  21
  22 GCC is distributed in the hope that it will be useful,
  23 but WITHOUT ANY WARRANTY; without even the implied warranty of
  24 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25 GNU General Public License for more details.
  26
  27 You should have received a copy of the GNU General Public License
  28 along with GCC; see the file COPYING.  If not, write to
  29 the Free Software Foundation, 59 Temple Place - Suite 330,
  30 Boston, MA 02111-1307, USA.  */
  31
  32 /*  Declare a pointer to void function type.  */
  33 typedef void (*func_ptr) (void);
  34
  35 #ifdef CRT_INIT
  36
  37 /* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
  38    to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
  39    __DTOR_END__ } per root executable and also one set of these symbols
  40    per shared library.  So in any given whole process image, we may have
  41    multiple definitions of each of these symbols.  In order to prevent
  42    these definitions from conflicting with one another, and in order to
  43    ensure that the proper lists are used for the initialization/finalization
  44    of each individual shared library (respectively), we give these symbols
  45    only internal (i.e. `static') linkage, and we also make it a point to
  46    refer to only the __CTOR_END__ symbol in crtfini.o and the __DTOR_LIST__
  47    symbol in crtinit.o, where they are defined.  */
  48
  49 static func_ptr __CTOR_LIST__[1]
  50   __attribute__ ((used, section (".ctors")))
  51      = { (func_ptr) (-1) };
  52
  53 static func_ptr __DTOR_LIST__[1]
  54   __attribute__ ((used, section (".dtors")))
  55      = { (func_ptr) (-1) };
  56
  57 /* Run all the global destructors on exit from the program.  */
  58
  59 /* Some systems place the number of pointers in the first word of the
  60    table.  On SVR4 however, that word is -1.  In all cases, the table is
  61    null-terminated.  On SVR4, we start from the beginning of the list and
  62    invoke each per-compilation-unit destructor routine in order
  63    until we find that null.
  64
  65    Note that this function MUST be static.  There will be one of these
  66    functions in each root executable and one in each shared library, but
  67    although they all have the same code, each one is unique in that it
  68    refers to one particular associated `__DTOR_LIST__' which belongs to the
  69    same particular root executable or shared library file.  */
  70
  71 static void __do_global_dtors (void)
  72 asm ("__do_global_dtors") __attribute__ ((used, section (".text")));
  73
  74 static void
  75 __do_global_dtors ()
  76 {
  77   func_ptr *p;
  78
  79   for (p = __DTOR_LIST__ + 1; *p; p++)
  80     (*p) ();
  81 }
  82
  83 /* .init section start.
  84    This must appear at the start of the .init section.  */
  85
  86 asm ("\n\
  87         .section .init,\"ax\",@progbits\n\
  88         .balign 4\n\
  89         .global __init\n\
  90 __init:\n\
  91         push fp\n\
  92         push lr\n\
  93         mv fp,sp\n\
  94         seth r0, #shigh(__fini)\n\
  95         add3 r0, r0, #low(__fini)\n\
  96         bl atexit\n\
  97         .fillinsn\n\
  98 ");
  99
 100 /* .fini section start.
 101    This must appear at the start of the .init section.  */
 102
 103 asm ("\n\
 104         .section .fini,\"ax\",@progbits\n\
 105         .balign 4\n\
 106         .global __fini\n\
 107 __fini:\n\
 108         push fp\n\
 109         push lr\n\
 110         mv fp,sp\n\
 111         bl __do_global_dtors\n\
 112         .fillinsn\n\
 113 ");
 114
 115 #endif /* CRT_INIT */
 116
 117 #ifdef CRT_FINI
 118
 119 /* Put a word containing zero at the end of each of our two lists of function
 120    addresses.  Note that the words defined here go into the .ctors and .dtors
 121    sections of the crtend.o file, and since that file is always linked in
 122    last, these words naturally end up at the very ends of the two lists
 123    contained in these two sections.  */
 124
 125 static func_ptr __CTOR_END__[1]
 126   __attribute__ ((used, section (".ctors")))
 127      = { (func_ptr) 0 };
 128
 129 static func_ptr __DTOR_END__[1]
 130   __attribute__ ((used, section (".dtors")))
 131      = { (func_ptr) 0 };
 132
 133 /* Run all global constructors for the program.
 134    Note that they are run in reverse order.  */
 135
 136 static void __do_global_ctors (void)
 137 asm ("__do_global_ctors") __attribute__ ((used, section (".text")));
 138
 139 static void
 140 __do_global_ctors ()
 141 {
 142   func_ptr *p;
 143
 144   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 145     (*p) ();
 146 }
 147
 148 /* .init section end.
 149    This must live at the end of the .init section.  */
 150
 151 asm ("\n\
 152         .section .init,\"ax\",@progbits\n\
 153         bl __do_global_ctors\n\
 154         mv sp,fp\n\
 155         pop lr\n\
 156         pop fp\n\
 157         jmp lr\n\
 158         .fillinsn\n\
 159 ");
 160
 161 /* .fini section end.
 162    This must live at the end of the .fini section.  */
 163
 164 asm ("\n\
 165         .section .fini,\"ax\",@progbits\n\
 166         mv sp,fp\n\
 167         pop lr\n\
 168         pop fp\n\
 169         jmp lr\n\
 170         .fillinsn\n\
 171 ");
 172
 173 #endif /* CRT_FINI */