gcc/config/i386/cygming-crtbegin.c

   1 /* crtbegin object for windows32 targets.
   2    Copyright (C) 2007, 2009, 2010  Free Software Foundation, Inc.
   3
   4    Contributed by Danny Smith <dannysmith@users.sourceforge.net>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 /* Target machine header files require this define. */
  28 #define IN_LIBGCC2
  29
  30 #include "auto-host.h"
  31 #include "tconfig.h"
  32 #include "tsystem.h"
  33 #include "coretypes.h"
  34 #include "tm.h"
  35 #include "unwind-dw2-fde.h"
  36
  37 #define WIN32_LEAN_AND_MEAN
  38 #include <windows.h>
  39
  40 #ifndef LIBGCC_SONAME
  41 #define LIBGCC_SONAME "libgcc_s.dll"
  42 #endif
  43
  44 #ifndef LIBGCJ_SONAME
  45 #define LIBGCJ_SONAME "libgcj_s.dll"
  46 #endif
  47
  48
  49 /* Make the declarations weak.  This is critical for
  50    _Jv_RegisterClasses because it lives in libgcj.a  */
  51 extern void __register_frame_info (const void *, struct object *)
  52                                    TARGET_ATTRIBUTE_WEAK;
  53 extern void *__deregister_frame_info (const void *)
  54                                       TARGET_ATTRIBUTE_WEAK;
  55 extern void _Jv_RegisterClasses (const void *) TARGET_ATTRIBUTE_WEAK;
  56
  57 #if defined(HAVE_LD_RO_RW_SECTION_MIXING)
  58 # define EH_FRAME_SECTION_CONST const
  59 #else
  60 # define EH_FRAME_SECTION_CONST
  61 #endif
  62
  63 /* Stick a label at the beginning of the frame unwind info so we can
  64    register/deregister it with the exception handling library code.  */
  65 #if DWARF2_UNWIND_INFO
  66 static EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
  67   __attribute__((used, section(EH_FRAME_SECTION_NAME), aligned(4)))
  68   = { };
  69
  70 static struct object obj;
  71 #endif
  72
  73 #if TARGET_USE_JCR_SECTION
  74 static void *__JCR_LIST__[]
  75   __attribute__ ((used, section(JCR_SECTION_NAME), aligned(4)))
  76   = { };
  77 #endif
  78
  79 /* Pull in references from libgcc.a(unwind-dw2-fde.o) in the
  80    startfile. These are referenced by a ctor and dtor in crtend.o.  */
  81 extern void __gcc_register_frame (void);
  82 extern void __gcc_deregister_frame (void);
  83
  84 void
  85 __gcc_register_frame (void)
  86 {
  87 #if DWARF2_UNWIND_INFO
  88 /* Weak undefined symbols won't be pulled in from dlls; hence
  89    we first test if the dll is already loaded and, if so,
  90    get the symbol's address at run-time.  If the dll is not loaded,
  91    fallback to weak linkage to static archive.  */
  92
  93   void (*register_frame_fn) (const void *, struct object *);
  94   HANDLE h = GetModuleHandle (LIBGCC_SONAME);
  95   if (h)
  96     register_frame_fn = (void (*) (const void *, struct object *))
  97                         GetProcAddress (h, "__register_frame_info");
  98   else
  99     register_frame_fn = __register_frame_info;
 100   if (register_frame_fn)
 101      register_frame_fn (__EH_FRAME_BEGIN__, &obj);
 102 #endif
 103
 104 #if TARGET_USE_JCR_SECTION
 105   if (__JCR_LIST__[0])
 106     {
 107       void (*register_class_fn) (const void *);
 108       HANDLE h = GetModuleHandle (LIBGCJ_SONAME);
 109       if (h)
 110         register_class_fn = (void (*) (const void *))
 111                              GetProcAddress (h, "_Jv_RegisterClasses");
 112       else
 113         register_class_fn = _Jv_RegisterClasses;
 114
 115       if (register_class_fn)
 116         register_class_fn (__JCR_LIST__);
 117     }
 118 #endif
 119 }
 120
 121 void
 122 __gcc_deregister_frame (void)
 123 {
 124 #if DWARF2_UNWIND_INFO
 125   void *  (*deregister_frame_fn) (const void *);
 126   HANDLE h = GetModuleHandle (LIBGCC_SONAME);
 127   if (h)
 128     deregister_frame_fn = (void* (*) (const void *))
 129                           GetProcAddress (h, "__deregister_frame_info");
 130   else
 131     deregister_frame_fn = __deregister_frame_info;
 132   if (deregister_frame_fn)
 133      deregister_frame_fn (__EH_FRAME_BEGIN__);
 134 #endif
 135 }