libgcc/gbl-ctors.h

   1 /* Definitions relating to the special __do_global_init function used
   2    for getting g++ file-scope static objects constructed.  This file
   3    will get included either by libgcc2.c (for systems that don't support
   4    a .init section) or by crtstuff.c (for those that do).
   5    Copyright (C) 1991-2023 Free Software Foundation, Inc.
   6    Contributed by Ron Guilmette (rfg@segfault.us.com)
   7
   8 This file is part of GCC.
   9
  10 GCC is free software; you can redistribute it and/or modify it under
  11 the terms of the GNU General Public License as published by the Free
  12 Software Foundation; either version 3, or (at your option) any later
  13 version.
  14
  15 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18 for more details.
  19
  20 Under Section 7 of GPL version 3, you are granted additional
  21 permissions described in the GCC Runtime Library Exception, version
  22 3.1, as published by the Free Software Foundation.
  23
  24 You should have received a copy of the GNU General Public License and
  25 a copy of the GCC Runtime Library Exception along with this program;
  26 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  27 <http://www.gnu.org/licenses/>.  */
  28
  29 /*      This file contains definitions and declarations of things
  30         relating to the normal start-up-time invocation of C++
  31         file-scope static object constructors.  These declarations
  32         and definitions are used by *both* libgcc2.c and by crtstuff.c.
  33
  34         Note that this file should only be compiled with GCC.
  35 */
  36
  37 #ifndef GCC_GBL_CTORS_H
  38 #define GCC_GBL_CTORS_H
  39
  40 /*  Declare a pointer to void function type.  */
  41
  42 typedef void (*func_ptr) (void);
  43
  44 /* Declare the set of symbols use as begin and end markers for the lists
  45    of global object constructors and global object destructors.  */
  46
  47 extern func_ptr __CTOR_LIST__[];
  48 extern func_ptr __DTOR_LIST__[];
  49
  50 /* Declare the routine which needs to get invoked at program start time.  */
  51
  52 extern void __do_global_ctors (void);
  53
  54 /* Declare the routine which needs to get invoked at program exit time.  */
  55
  56 extern void __do_global_dtors (void);
  57
  58 /* Define a macro with the code which needs to be executed at program
  59    start-up time.  This macro is used in two places in crtstuff.c (for
  60    systems which support a .init section) and in one place in libgcc2.c
  61    (for those system which do *not* support a .init section).  For all
  62    three places where this code might appear, it must be identical, so
  63    we define it once here as a macro to avoid various instances getting
  64    out-of-sync with one another.  */
  65
  66 /* Some systems place the number of pointers
  67    in the first word of the table.
  68    On other systems, that word is -1.
  69    In all cases, the table is null-terminated.
  70    If the length is not recorded, count up to the null.  */
  71
  72 /* Some systems use a different strategy for finding the ctors.
  73    For example, svr3.  */
  74 #ifndef DO_GLOBAL_CTORS_BODY
  75 #define DO_GLOBAL_CTORS_BODY                                            \
  76 do {                                                                    \
  77   __SIZE_TYPE__ nptrs = (__SIZE_TYPE__) __CTOR_LIST__[0];               \
  78   unsigned i;                                                           \
  79   if (nptrs == (__SIZE_TYPE__)-1)                                       \
  80     for (nptrs = 0; __CTOR_LIST__[nptrs + 1] != 0; nptrs++);            \
  81   for (i = nptrs; i >= 1; i--)                                          \
  82     __CTOR_LIST__[i] ();                                                \
  83 } while (0)
  84 #endif
  85
  86 #endif /* GCC_GBL_CTORS_H */