l4/pkg/crtn/lib/src/construction.c

   1 /*
   2  * (c) 2008-2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
   3  *               Alexander Warg <warg@os.inf.tu-dresden.de>
   4  *     economic rights: Technische Universität Dresden (Germany)
   5  * This file is part of TUD:OS and distributed under the terms of the
   6  * GNU Lesser General Public License 2.1.
   7  * Please see the COPYING-LGPL-2.1 file for details.
   8  */
   9 #include <l4/crtn/crt0.h>
  10
  11 //#define DEBUG
  12
  13 #ifdef DEBUG
  14 #include <l4/sys/kdebug.h>
  15 #endif
  16
  17 int __cxa_atexit(void (*function)(void*), void *arg, void *dso_handle);
  18
  19 #define BEG             { (crt0_hook) ~1UL }
  20 #define END             { (crt0_hook)  0UL }
  21
  22 // make sure that unused symbols are not discarded
  23 #if (__GNUC__ == 3 && __GNUC_MINOR__ >= 3) || __GNUC__ >= 4
  24 #define SECTION(x)      __attribute__((used, section( x )))
  25 #else
  26 #define SECTION(x)      __attribute__((section( x )))
  27 #endif
  28
  29 typedef void (*const crt0_hook)(void);
  30
  31 static crt0_hook const __CTOR_BEG__[1]   SECTION(".mark_beg_ctors")   = BEG;
  32 static crt0_hook const __CTOR_END__[1]   SECTION(".mark_end_ctors")   = END;
  33 static crt0_hook const __C_CTOR_BEG__[1] SECTION(".mark_beg_c_ctors") = BEG;
  34 static crt0_hook const __C_CTOR_END__[1] SECTION(".mark_end_c_ctors") = END;
  35 static crt0_hook const __DTOR_BEG__[1]   SECTION(".mark_beg_dtors")   = BEG;
  36 static crt0_hook const __DTOR_END__[1]   SECTION(".mark_end_dtors")   = END;
  37 static crt0_hook const __C_DTOR_BEG__[1] SECTION(".mark_beg_c_dtors") = BEG;
  38 static crt0_hook const __C_DTOR_END__[1] SECTION(".mark_end_c_dtors") = END;
  39
  40
  41 static void
  42 run_hooks_forward(crt0_hook *list, const char *name)
  43 {
  44   (void)name;
  45 #ifdef DEBUG
  46   outstring("list (forward) ");
  47   outstring(name);
  48   outstring(" @ ");
  49   outhex32((unsigned)list);
  50   outchar('\n');
  51 #endif
  52   list++;
  53   while (*list)
  54     {
  55 #ifdef DEBUG
  56       outstring("  calling ");
  57       outhex32((unsigned)*list);
  58       outchar('\n');
  59 #endif
  60       (**list)();
  61       list++;
  62     }
  63 }
  64
  65 static void
  66 run_hooks_backward(crt0_hook *list, const char *name)
  67 {
  68   (void)name;
  69 #ifdef DEBUG
  70   outstring("list (backward) ");
  71   outstring(name);
  72   outstring(" @ ");
  73   outhex32((unsigned)list);
  74   outchar('\n');
  75 #endif
  76   list--;
  77   while (*list != (crt0_hook)~1UL)
  78     {
  79 #ifdef DEBUG
  80       outstring("  calling ");
  81       outhex32((unsigned)*list);
  82       outchar('\n');
  83 #endif
  84       (**list)();
  85       list--;
  86     }
  87 }
  88
  89 static void
  90 static_construction(void)
  91 {
  92   /* call constructors made with L4_C_CTOR */
  93   run_hooks_forward(__C_CTOR_BEG__, "__C_CTOR_BEG__");
  94
  95   /* call constructors made with __attribute__((constructor))
  96    * and static C++ constructors */
  97   run_hooks_backward(__CTOR_END__, "__CTOR_END__");
  98 }
  99
 100 static void
 101 static_destruction(void)
 102 {
 103   /* call destructors made with __attribute__((destructor))
 104    * and static C++ destructors */
 105   run_hooks_forward(__DTOR_BEG__, "__DTOR_BEG__");
 106
 107   /* call destructors made with L4_C_DTOR except system destructors */
 108   run_hooks_backward(__C_DTOR_END__, "__C_DTOR_END__");
 109 }
 110
 111 extern void *__dso_handle __attribute__((weak));
 112
 113 /* is called by crt0 immediately before calling __main() */
 114 void
 115 crt0_construction(void)
 116 {
 117   static_construction();
 118   __cxa_atexit((void (*)(void*))&static_destruction, 0,
 119       &__dso_handle == 0 ? 0 : __dso_handle);
 120 }
 121
 122 asm (".hidden _init");
 123
 124 /* this special function is called for initializing static libraries */
 125 void _init(void) __attribute__((section(".init")));
 126 void
 127 _init(void)
 128 {
 129   static_construction();
 130 }