libgcc/config/arc/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) 1995-2017 Free Software Foundation, Inc.
   5    Contributor: Joern Rennecke <joern.rennecke@embecosm.com>
   6                 on behalf of Synopsys Inc.
   7
   8 This file is part of GCC.
   9
  10 GCC is free software; you can redistribute it and/or modify
  11 it under the terms of the GNU General Public License as published by
  12 the Free Software Foundation; either version 3, or (at your option)
  13 any later version.
  14
  15 GCC is distributed in the hope that it will be useful,
  16 but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 GNU General Public License 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 /*  Declare a pointer to void function type.  */
  30 typedef void (*func_ptr) (void);
  31
  32 #ifdef CRT_INIT
  33
  34 /* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
  35    to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
  36    __DTOR_END__ } per root executable and also one set of these symbols
  37    per shared library.  So in any given whole process image, we may have
  38    multiple definitions of each of these symbols.  In order to prevent
  39    these definitions from conflicting with one another, and in order to
  40    ensure that the proper lists are used for the initialization/finalization
  41    of each individual shared library (respectively), we give these symbols
  42    only internal (i.e. `static') linkage, and we also make it a point to
  43    refer to only the __CTOR_END__ symbol in crtfini.o and the __DTOR_LIST__
  44    symbol in crtinit.o, where they are defined.  */
  45
  46 static func_ptr __CTOR_LIST__[1] __attribute__ ((section (".ctors")))
  47      = { (func_ptr) (-1) };
  48
  49 static func_ptr __DTOR_LIST__[1] __attribute__ ((section (".dtors")))
  50      = { (func_ptr) (-1) };
  51
  52 /* Run all the global destructors on exit from the program.  */
  53
  54 /* Some systems place the number of pointers in the first word of the
  55    table.  On SVR4 however, that word is -1.  In all cases, the table is
  56    null-terminated.  On SVR4, we start from the beginning of the list and
  57    invoke each per-compilation-unit destructor routine in order
  58    until we find that null.
  59
  60    Note that this function MUST be static.  There will be one of these
  61    functions in each root executable and one in each shared library, but
  62    although they all have the same code, each one is unique in that it
  63    refers to one particular associated `__DTOR_LIST__' which belongs to the
  64    same particular root executable or shared library file.  */
  65
  66 static void __do_global_dtors (void)
  67 asm ("__do_global_dtors") __attribute__ ((section (".text")));
  68
  69 static void
  70 __do_global_dtors (void)
  71 {
  72   func_ptr *p;
  73   for (p = __DTOR_LIST__ + 1; *p; p++)
  74     (*p) ();
  75 }
  76
  77 /* .init section start.
  78    This must appear at the start of the .init section.  */
  79
  80 asm ("\n\
  81         .section .init\n\
  82         .global init\n\
  83         .word 0\n\
  84 init:\n\
  85         st blink,[sp,4]\n\
  86         st fp,[sp]\n\
  87         mov fp,sp\n\
  88         sub sp,sp,16\n\
  89 ");
  90
  91 /* .fini section start.
  92    This must appear at the start of the .init section.  */
  93
  94 asm ("\n\
  95         .section .fini\n\
  96         .global fini\n\
  97         .word 0\n\
  98 fini:\n\
  99         st blink,[sp,4]\n\
 100         st fp,[sp]\n\
 101         mov fp,sp\n\
 102         sub sp,sp,16\n\
 103         bl.nd __do_global_dtors\n\
 104 ");
 105
 106 #endif /* CRT_INIT */
 107
 108 #ifdef CRT_FINI
 109
 110 /* Put a word containing zero at the end of each of our two lists of function
 111    addresses.  Note that the words defined here go into the .ctors and .dtors
 112    sections of the crtend.o file, and since that file is always linked in
 113    last, these words naturally end up at the very ends of the two lists
 114    contained in these two sections.  */
 115
 116 static func_ptr __CTOR_END__[1] __attribute__ ((section (".ctors")))
 117      = { (func_ptr) 0 };
 118
 119 static func_ptr __DTOR_END__[1] __attribute__ ((section (".dtors")))
 120      = { (func_ptr) 0 };
 121
 122 /* Run all global constructors for the program.
 123    Note that they are run in reverse order.  */
 124
 125 static void __do_global_ctors (void)
 126 asm ("__do_global_ctors") __attribute__ ((section (".text")));
 127
 128 static void
 129 __do_global_ctors (void)
 130 {
 131   func_ptr *p;
 132   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 133     (*p) ();
 134 }
 135
 136 /* .init section end.
 137    This must live at the end of the .init section.  */
 138
 139 asm ("\n\
 140         .section .init\n\
 141         bl.nd __do_global_ctors\n\
 142         ld blink,[fp,4]\n\
 143         j.d blink\n\
 144         ld.a fp,[sp,16]\n\
 145 ");
 146
 147 /* .fini section end.
 148    This must live at the end of the .fini section.  */
 149
 150 asm ("\n\
 151         .section .fini\n\
 152         ld blink,[fp,4]\n\
 153         j.d blink\n\
 154         ld.a fp,[sp,16]\n\
 155 ");
 156
 157 #endif /* CRT_FINI */