1 /* crtbegin object for windows32 targets. 2 Copyright (C) 2007-2022 Free Software Foundation, Inc. 3 4 Contributed by Danny Smith <dannysmith (at) 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 #if DWARF2_UNWIND_INFO 46 /* Make the declarations weak. This is critical for 47 _Jv_RegisterClasses because it lives in libgcj.a */ 48 extern void __register_frame_info (__attribute__((unused)) const void *, 49 __attribute__((unused)) struct object *) 50 TARGET_ATTRIBUTE_WEAK; 51 extern void *__deregister_frame_info (__attribute__((unused)) const void *) 52 TARGET_ATTRIBUTE_WEAK; 53 54 /* Work around for current cygwin32 build problems (Bug gas/16858). 55 Compile weak default functions only for 64-bit systems, 56 when absolutely necessary. */ 57 #ifdef __x86_64__ 58 TARGET_ATTRIBUTE_WEAK void 59 __register_frame_info (__attribute__((unused)) const void *p, 60 __attribute__((unused)) struct object *o) 61 { 62 } 63 64 TARGET_ATTRIBUTE_WEAK void * 65 __deregister_frame_info (__attribute__((unused)) const void *p) 66 { 67 return (void*) 0; 68 } 69 #endif 70 #endif /* DWARF2_UNWIND_INFO */ 71 72 #if defined(HAVE_LD_RO_RW_SECTION_MIXING) 73 # define EH_FRAME_SECTION_CONST const 74 #else 75 # define EH_FRAME_SECTION_CONST 76 #endif 77 78 /* Stick a label at the beginning of the frame unwind info so we can 79 register/deregister it with the exception handling library code. */ 80 #if DWARF2_UNWIND_INFO 81 static EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[] 82 __attribute__((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4))) 83 = { }; 84 85 static struct object obj; 86 87 /* Handle of libgcc's DLL reference. */ 88 HANDLE hmod_libgcc; 89 static void * (*deregister_frame_fn) (const void *) = NULL; 90 #endif 91 92 #ifdef __CYGWIN__ 93 /* Declare the __dso_handle variable. It should have a unique value 94 in every shared-object; in a main program its value is zero. The 95 object should in any case be protected. This means the instance 96 in one DSO or the main program is not used in another object. The 97 dynamic linker takes care of this. */ 98 99 #ifdef CRTSTUFFS_O 100 extern void *__ImageBase; 101 void *__dso_handle = &__ImageBase; 102 #else 103 void *__dso_handle = 0; 104 #endif 105 106 #endif /* __CYGWIN__ */ 107 108 109 /* Pull in references from libgcc.a(unwind-dw2-fde.o) in the 110 startfile. These are referenced by a ctor and dtor in crtend.o. */ 111 extern void __gcc_register_frame (void); 112 extern void __gcc_deregister_frame (void); 113 114 void 115 __gcc_register_frame (void) 116 { 117 #if DWARF2_UNWIND_INFO 118 /* Weak undefined symbols won't be pulled in from dlls; hence 119 we first test if the dll is already loaded and, if so, 120 get the symbol's address at run-time. If the dll is not loaded, 121 fallback to weak linkage to static archive. */ 122 123 void (*register_frame_fn) (const void *, struct object *); 124 HANDLE h = GetModuleHandle (LIBGCC_SONAME); 125 126 if (h) 127 { 128 /* Increasing the load-count of LIBGCC_SONAME DLL. */ 129 hmod_libgcc = LoadLibrary (LIBGCC_SONAME); 130 register_frame_fn = (void (*) (const void *, struct object *)) 131 GetProcAddress (h, "__register_frame_info"); 132 deregister_frame_fn = (void* (*) (const void *)) 133 GetProcAddress (h, "__deregister_frame_info"); 134 } 135 else 136 { 137 register_frame_fn = __register_frame_info; 138 deregister_frame_fn = __deregister_frame_info; 139 } 140 if (register_frame_fn) 141 register_frame_fn (__EH_FRAME_BEGIN__, &obj); 142 #endif 143 144 #if DEFAULT_USE_CXA_ATEXIT 145 /* If we use the __cxa_atexit method to register C++ dtors 146 at object construction, also use atexit to register eh frame 147 info cleanup. */ 148 atexit(__gcc_deregister_frame); 149 #endif /* DEFAULT_USE_CXA_ATEXIT */ 150 } 151 152 void 153 __gcc_deregister_frame (void) 154 { 155 #if DWARF2_UNWIND_INFO 156 if (deregister_frame_fn) 157 deregister_frame_fn (__EH_FRAME_BEGIN__); 158 if (hmod_libgcc) 159 FreeLibrary (hmod_libgcc); 160 #endif 161 } 162
Indexes created Sat Feb 28 05:31:39 UTC 2026