compiler/autoinit/initexitsets.c

   1 /*
   2     Copyright © 2009-2016, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: autoinit library - handle init and exit symolsets
   6 */
   7 #include <aros/startup.h>
   8 #include <aros/symbolsets.h>
   9 #include <setjmp.h>
  10
  11 #define DEBUG 0
  12 #include <aros/debug.h>
  13
  14 int __noinitexitsets __attribute__((weak)) = 0;
  15 extern void *__eh_frame_start;
  16
  17 /*
  18  * These two functions could have been overriden by libgcc's Dwarf2 unwinder code.
  19  * (used for example for C++ exception handling).
  20  * We do this trick in order to avoid linking in the whole unwinder just by referencing
  21  * these functions. This helps to keep C executables smaller.
  22  * Note that we call them when libraries are already open because __register_frame()
  23  * internally uses malloc(). See unwind-dw2-fde.c in gcc source code.
  24  *
  25  * TODO: Calling these functions from here means that only plain executables register their
  26  * exception frames. This means that:
  27  * a) C++ exceptions won't work inside shared libraries.
  28  * This can be easily fixed in libraries' startup code. But libraries are separate executables, and
  29  * this would mean that they register their own frames in their own copy of libgcc runtime. As a
  30  * consequence:
  31  * b) C++ exceptions can't be thrown outside of shared libraries using this approach.
  32  * (b) is more difficult to fix. When some program opens the library, it should be able to register
  33  * its frames and actually process exceptions using program's runtime. This can be implemented
  34  * in a number of ways, all of them involving development of some ABI standard.
  35  */
  36 void __attribute__((weak)) __register_frame(void *begin) {}
  37 void __attribute__((weak)) __deregister_frame(void *begin) {}
  38
  39 THIS_PROGRAM_HANDLES_SYMBOLSET(LIBS)
  40 THIS_PROGRAM_HANDLES_SYMBOLSET(CTORS)
  41 THIS_PROGRAM_HANDLES_SYMBOLSET(DTORS)
  42 THIS_PROGRAM_HANDLES_SYMBOLSET(INIT_ARRAY)
  43 THIS_PROGRAM_HANDLES_SYMBOLSET(FINI_ARRAY)
  44 THIS_PROGRAM_HANDLES_SYMBOLSET(INIT)
  45 THIS_PROGRAM_HANDLES_SYMBOLSET(EXIT)
  46 DEFINESET(CTORS);
  47 DEFINESET(DTORS);
  48 DEFINESET(INIT_ARRAY);
  49 DEFINESET(FINI_ARRAY);
  50 DEFINESET(INIT);
  51 DEFINESET(EXIT);
  52
  53 static void __startup_initexit(struct ExecBase *SysBase)
  54 {
  55     D(bug("Entering __startup_initexit\n"));
  56
  57     if (set_open_libraries())
  58     {
  59         __register_frame(&__eh_frame_start);
  60
  61         if (set_call_funcs(SETNAME(INIT), 1, 1))
  62         {
  63             /* ctors/dtors get called in inverse order than init funcs */
  64             set_call_funcs(SETNAME(CTORS), -1, 0);
  65
  66             set_call_funcs(SETNAME(INIT_ARRAY), 1, 0);
  67
  68             __startup_entries_next();
  69
  70             set_call_funcs(SETNAME(FINI_ARRAY), -1, 0);
  71
  72             set_call_funcs(SETNAME(DTORS), 1, 0);
  73         }
  74         set_call_funcs(SETNAME(EXIT), -1, 0);
  75
  76         __deregister_frame(&__eh_frame_start);
  77     }
  78     set_close_libraries();
  79
  80     D(bug("Leaving __startup_initexit\n"));
  81 }
  82
  83 ADD2SET(__startup_initexit, PROGRAM_ENTRIES, -20);