1 /* .init/.fini section handling + C++ global constructor/destructor 2 handling of Andes NDS32 cpu for GNU compiler. 3 This file is based on crtstuff.c, sol2-crti.asm, sol2-crtn.asm. 4 Copyright (C) 2012-2019 Free Software Foundation, Inc. 5 Contributed by Andes Technology Corporation. 6 7 This file is part of GCC. 8 9 GCC is free software; you can redistribute it and/or modify it 10 under the terms of the GNU General Public License as published 11 by the Free Software Foundation; either version 3, or (at your 12 option) any later version. 13 14 GCC is distributed in the hope that it will be useful, but WITHOUT 15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 17 License for more details. 18 19 Under Section 7 of GPL version 3, you are granted additional 20 permissions described in the GCC Runtime Library Exception, version 21 3.1, as published by the Free Software Foundation. 22 23 You should have received a copy of the GNU General Public License and 24 a copy of the GCC Runtime Library Exception along with this program; 25 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 26 <http://www.gnu.org/licenses/>. */ 27 28 #include <stddef.h> 29 /* Need header file for `struct object' type. */ 30 #include "../libgcc/unwind-dw2-fde.h" 31 32 /* Declare a pointer to void function type. */ 33 typedef void (*func_ptr) (void); 34 35 #ifdef CRT_BEGIN 36 37 /* NOTE: In order to be able to support SVR4 shared libraries, we arrange 38 to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__, 39 __DTOR_END__ } per root executable and also one set of these symbols 40 per shared library. So in any given whole process image, we may have 41 multiple definitions of each of these symbols. In order to prevent 42 these definitions from conflicting with one another, and in order to 43 ensure that the proper lists are used for the initialization/finalization 44 of each individual shared library (respectively), we give these symbols 45 only internal (i.e. `static') linkage, and we also make it a point to 46 refer to only the __CTOR_END__ symbol in crtfini.o and the __DTOR_LIST__ 47 symbol in crtinit.o, where they are defined. */ 48 49 static func_ptr __CTOR_LIST__[1] __attribute__ ((section (".ctors"), used)) 50 = { (func_ptr) 0 }; 51 52 static func_ptr __DTOR_LIST__[1] __attribute__ ((section (".dtors"), used)) 53 = { (func_ptr) 0 }; 54 55 56 #ifdef SUPPORT_UNWINDING_DWARF2 57 /* Preparation of exception handling with dwar2 mechanism registration. */ 58 59 asm ("\n\ 60 .section .eh_frame,\"aw\",@progbits\n\ 61 .global __EH_FRAME_BEGIN__\n\ 62 .type __EH_FRAME_BEGIN__, @object\n\ 63 .align 2\n\ 64 __EH_FRAME_BEGIN__:\n\ 65 ! Beginning location of eh_frame section\n\ 66 .previous\n\ 67 "); 68 69 extern func_ptr __EH_FRAME_BEGIN__[]; 70 71 72 /* Note that the following two functions are going to be chained into 73 constructor and destructor list, repectively. So these two declarations 74 must be placed after __CTOR_LIST__ and __DTOR_LIST. */ 75 extern void __nds32_register_eh(void) __attribute__((constructor, used)); 76 extern void __nds32_deregister_eh(void) __attribute__((destructor, used)); 77 78 /* Register the exception handling table as the first constructor. */ 79 void 80 __nds32_register_eh (void) 81 { 82 static struct object object; 83 if (__register_frame_info) 84 __register_frame_info (__EH_FRAME_BEGIN__, &object); 85 } 86 87 /* Unregister the exception handling table as a deconstructor. */ 88 void 89 __nds32_deregister_eh (void) 90 { 91 static int completed = 0; 92 93 if (completed) 94 return; 95 96 if (__deregister_frame_info) 97 __deregister_frame_info (__EH_FRAME_BEGIN__); 98 99 completed = 1; 100 } 101 #endif 102 103 /* Run all the global destructors on exit from the program. */ 104 105 /* Some systems place the number of pointers in the first word of the 106 table. On SVR4 however, that word is -1. In all cases, the table is 107 null-terminated. On SVR4, we start from the beginning of the list and 108 invoke each per-compilation-unit destructor routine in order 109 until we find that null. 110 111 Note that this function MUST be static. There will be one of these 112 functions in each root executable and one in each shared library, but 113 although they all have the same code, each one is unique in that it 114 refers to one particular associated `__DTOR_LIST__' which belongs to the 115 same particular root executable or shared library file. */ 116 117 static void __do_global_dtors (void) 118 asm ("__do_global_dtors") __attribute__ ((section (".text"), used)); 119 120 static void 121 __do_global_dtors (void) 122 { 123 func_ptr *p; 124 for (p = __DTOR_LIST__ + 1; *p; p++) 125 (*p) (); 126 } 127 128 /* .init section start. 129 This must appear at the start of the .init section. */ 130 131 asm ("\n\ 132 .section .init\n\ 133 .global _init\n\ 134 .type _init, @function\n\ 135 _init:\n\ 136 ! 1. store $fp\n\ 137 ! 2. adjust $fp by $sp\n\ 138 ! 3. adjust $sp\n\ 139 "); 140 141 /* .fini section start. 142 This must appear at the start of the .fini section. */ 143 144 asm ("\n\ 145 .section .fini\n\ 146 .global _fini\n\ 147 .type _fini, @function\n\ 148 _fini:\n\ 149 ! 1. store $fp\n\ 150 ! 2. adjust $fp by $sp\n\ 151 ! 3. adjust $sp\n\ 152 ! 4. call __do_global_dtors\n\ 153 j __do_global_dtors\n\ 154 "); 155 156 #endif /* CRT_BEGIN */ 157 158 #ifdef CRT_END 159 160 /* Define __dso_handle which would be needed for C++ library. 161 Since our elf-toolchain only builds programs with static link, 162 we can directly define 'void *__dso_handle = 0'. */ 163 void *__dso_handle = 0; 164 165 /* Put a word containing zero at the end of each of our two lists of function 166 addresses. Note that the words defined here go into the .ctors and .dtors 167 sections of the crtend.o file, and since that file is always linked in 168 last, these words naturally end up at the very ends of the two lists 169 contained in these two sections. */ 170 171 static func_ptr __CTOR_END__[1] __attribute__ ((section (".ctors"), used)) 172 = { (func_ptr) 0 }; 173 174 static func_ptr __DTOR_END__[1] __attribute__ ((section (".dtors"), used)) 175 = { (func_ptr) 0 }; 176 177 #ifdef SUPPORT_UNWINDING_DWARF2 178 /* ZERO terminator in .eh_frame section. */ 179 asm ("\n\ 180 .section .eh_frame,\"aw\",@progbits\n\ 181 .global __EH_FRAME_END__\n\ 182 .type __EH_FRAME_END__, @object\n\ 183 .align 2\n\ 184 __EH_FRAME_END__:\n\ 185 ! End location of eh_frame section with ZERO terminator\n\ 186 .word 0\n\ 187 .previous\n\ 188 "); 189 #endif 190 191 /* Run all global constructors for the program. 192 Note that they are run in reverse order. */ 193 194 static void __do_global_ctors (void) 195 asm ("__do_global_ctors") __attribute__ ((section (".text"), used)); 196 197 static void 198 __do_global_ctors (void) 199 { 200 func_ptr *p; 201 for (p = __CTOR_END__ - 1; *p; p--) 202 (*p) (); 203 } 204 205 /* .init section end. 206 This must live at the end of the .init section. */ 207 208 asm ("\n\ 209 .section .init\n\ 210 ! 1. call __do_global_ctors\n\ 211 ! 2. adjust back $sp\n\ 212 ! 3. restore $fp\n\ 213 j __do_global_ctors\n\ 214 "); 215 216 /* .fini section end. 217 This must live at the end of the .fini section. */ 218 219 asm ("\n\ 220 .section .fini\n\ 221 ! 1. adjust back $sp\n\ 222 ! 2. restore $fp\n\ 223 "); 224 225 #endif /* CRT_END */ 226