gcc-4_8-branch/libgcc/config/i386/cygming-crtbegin.c

   1 /* crtbegin object for windows32 targets.
   2    Copyright (C) 2007-2013 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 "libgcc_tm.h"
  36 #include "unwind-dw2-fde.h"
  37
  38 #define WIN32_LEAN_AND_MEAN
  39 #include <windows.h>
  40
  41 #ifndef LIBGCC_SONAME
  42 #define LIBGCC_SONAME "libgcc_s.dll"
  43 #endif
  44
  45 #ifndef LIBGCJ_SONAME
  46 #define LIBGCJ_SONAME "libgcj_s.dll"
  47 #endif
  48
  49
  50 /* Make the declarations weak.  This is critical for
  51    _Jv_RegisterClasses because it lives in libgcj.a  */
  52 extern void __register_frame_info (const void *, struct object *)
  53                                    TARGET_ATTRIBUTE_WEAK;
  54 extern void *__deregister_frame_info (const void *)
  55                                       TARGET_ATTRIBUTE_WEAK;
  56 extern void _Jv_RegisterClasses (const void *) TARGET_ATTRIBUTE_WEAK;
  57
  58 #if defined(HAVE_LD_RO_RW_SECTION_MIXING)
  59 # define EH_FRAME_SECTION_CONST const
  60 #else
  61 # define EH_FRAME_SECTION_CONST
  62 #endif
  63
  64 /* Stick a label at the beginning of the frame unwind info so we can
  65    register/deregister it with the exception handling library code.  */
  66 #if DWARF2_UNWIND_INFO
  67 static EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
  68   __attribute__((used, section(EH_FRAME_SECTION_NAME), aligned(4)))
  69   = { };
  70
  71 static struct object obj;
  72
  73 /* Handle of libgcc's DLL reference.  */
  74 HANDLE hmod_libgcc;
  75 #endif
  76
  77 #if TARGET_USE_JCR_SECTION
  78 static void *__JCR_LIST__[]
  79   __attribute__ ((used, section(JCR_SECTION_NAME), aligned(4)))
  80   = { };
  81 #endif
  82
  83 /* Pull in references from libgcc.a(unwind-dw2-fde.o) in the
  84    startfile. These are referenced by a ctor and dtor in crtend.o.  */
  85 extern void __gcc_register_frame (void);
  86 extern void __gcc_deregister_frame (void);
  87
  88 void
  89 __gcc_register_frame (void)
  90 {
  91 #if DWARF2_UNWIND_INFO
  92 /* Weak undefined symbols won't be pulled in from dlls; hence
  93    we first test if the dll is already loaded and, if so,
  94    get the symbol's address at run-time.  If the dll is not loaded,
  95    fallback to weak linkage to static archive.  */
  96
  97   void (*register_frame_fn) (const void *, struct object *);
  98   HANDLE h = GetModuleHandle (LIBGCC_SONAME);
  99
 100   if (h)
 101     {
 102       /* Increasing the load-count of LIBGCC_SONAME DLL.  */
 103       hmod_libgcc = LoadLibrary (LIBGCC_SONAME);
 104       register_frame_fn = (void (*) (const void *, struct object *))
 105                           GetProcAddress (h, "__register_frame_info");
 106     }
 107   else
 108     register_frame_fn = __register_frame_info;
 109   if (register_frame_fn)
 110      register_frame_fn (__EH_FRAME_BEGIN__, &obj);
 111 #endif
 112
 113 #if TARGET_USE_JCR_SECTION
 114   if (__JCR_LIST__[0])
 115     {
 116       void (*register_class_fn) (const void *);
 117       HANDLE h = GetModuleHandle (LIBGCJ_SONAME);
 118       if (h)
 119         register_class_fn = (void (*) (const void *))
 120                              GetProcAddress (h, "_Jv_RegisterClasses");
 121       else
 122         register_class_fn = _Jv_RegisterClasses;
 123
 124       if (register_class_fn)
 125         register_class_fn (__JCR_LIST__);
 126     }
 127 #endif
 128 }
 129
 130 void
 131 __gcc_deregister_frame (void)
 132 {
 133 #if DWARF2_UNWIND_INFO
 134   void *  (*deregister_frame_fn) (const void *);
 135   HANDLE h = GetModuleHandle (LIBGCC_SONAME);
 136   if (h)
 137     deregister_frame_fn = (void* (*) (const void *))
 138                           GetProcAddress (h, "__deregister_frame_info");
 139   else
 140     deregister_frame_fn = __deregister_frame_info;
 141   if (deregister_frame_fn)
 142      deregister_frame_fn (__EH_FRAME_BEGIN__);
 143   if (hmod_libgcc)
 144     FreeLibrary (hmod_libgcc);
 145 #endif
 146 }