initfini.c revision 1.1.1.4
1/* .init/.fini section handling + C++ global constructor/destructor handling. 2 This file is based on crtstuff.c, sol2-crti.asm, sol2-crtn.asm. 3 4 Copyright (C) 1995-2018 Free Software Foundation, Inc. 5 Contributor: Joern Rennecke <joern.rennecke@embecosm.com> 6 on behalf of Synopsys Inc. 7 8This file is part of GCC. 9 10GCC is free software; you can redistribute it and/or modify 11it under the terms of the GNU General Public License as published by 12the Free Software Foundation; either version 3, or (at your option) 13any later version. 14 15GCC is distributed in the hope that it will be useful, 16but WITHOUT ANY WARRANTY; without even the implied warranty of 17MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18GNU General Public License for more details. 19 20Under Section 7 of GPL version 3, you are granted additional 21permissions described in the GCC Runtime Library Exception, version 223.1, as published by the Free Software Foundation. 23 24You should have received a copy of the GNU General Public License and 25a copy of the GCC Runtime Library Exception along with this program; 26see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 27<http://www.gnu.org/licenses/>. */ 28 29/* Declare a pointer to void function type. */ 30typedef void (*func_ptr) (void); 31 32#ifdef CRT_INIT 33 34/* NOTE: In order to be able to support SVR4 shared libraries, we arrange 35 to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__, 36 __DTOR_END__ } per root executable and also one set of these symbols 37 per shared library. So in any given whole process image, we may have 38 multiple definitions of each of these symbols. In order to prevent 39 these definitions from conflicting with one another, and in order to 40 ensure that the proper lists are used for the initialization/finalization 41 of each individual shared library (respectively), we give these symbols 42 only internal (i.e. `static') linkage, and we also make it a point to 43 refer to only the __CTOR_END__ symbol in crtfini.o and the __DTOR_LIST__ 44 symbol in crtinit.o, where they are defined. */ 45 46static func_ptr __CTOR_LIST__[1] __attribute__ ((section (".ctors"))) 47 = { (func_ptr) (-1) }; 48 49static func_ptr __DTOR_LIST__[1] __attribute__ ((section (".dtors"))) 50 = { (func_ptr) (-1) }; 51 52/* Run all the global destructors on exit from the program. */ 53 54/* Some systems place the number of pointers in the first word of the 55 table. On SVR4 however, that word is -1. In all cases, the table is 56 null-terminated. On SVR4, we start from the beginning of the list and 57 invoke each per-compilation-unit destructor routine in order 58 until we find that null. 59 60 Note that this function MUST be static. There will be one of these 61 functions in each root executable and one in each shared library, but 62 although they all have the same code, each one is unique in that it 63 refers to one particular associated `__DTOR_LIST__' which belongs to the 64 same particular root executable or shared library file. */ 65 66static void __do_global_dtors (void) 67asm ("__do_global_dtors") __attribute__ ((section (".text"))); 68 69static void 70__do_global_dtors (void) 71{ 72 func_ptr *p; 73 for (p = __DTOR_LIST__ + 1; *p; p++) 74 (*p) (); 75} 76 77/* .init section start. 78 This must appear at the start of the .init section. */ 79 80asm ("\n\ 81 .section .init\n\ 82 .global init\n\ 83 .word 0\n\ 84init:\n\ 85 st blink,[sp,4]\n\ 86 st fp,[sp]\n\ 87 mov fp,sp\n\ 88 sub sp,sp,16\n\ 89"); 90 91/* .fini section start. 92 This must appear at the start of the .init section. */ 93 94asm ("\n\ 95 .section .fini\n\ 96 .global fini\n\ 97 .word 0\n\ 98fini:\n\ 99 st blink,[sp,4]\n\ 100 st fp,[sp]\n\ 101 mov fp,sp\n\ 102 sub sp,sp,16\n\ 103 bl.nd __do_global_dtors\n\ 104"); 105 106#endif /* CRT_INIT */ 107 108#ifdef CRT_FINI 109 110/* Put a word containing zero at the end of each of our two lists of function 111 addresses. Note that the words defined here go into the .ctors and .dtors 112 sections of the crtend.o file, and since that file is always linked in 113 last, these words naturally end up at the very ends of the two lists 114 contained in these two sections. */ 115 116static func_ptr __CTOR_END__[1] __attribute__ ((section (".ctors"))) 117 = { (func_ptr) 0 }; 118 119static func_ptr __DTOR_END__[1] __attribute__ ((section (".dtors"))) 120 = { (func_ptr) 0 }; 121 122/* Run all global constructors for the program. 123 Note that they are run in reverse order. */ 124 125static void __do_global_ctors (void) 126asm ("__do_global_ctors") __attribute__ ((section (".text"))); 127 128static void 129__do_global_ctors (void) 130{ 131 func_ptr *p; 132 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 133 (*p) (); 134} 135 136/* .init section end. 137 This must live at the end of the .init section. */ 138 139asm ("\n\ 140 .section .init\n\ 141 bl.nd __do_global_ctors\n\ 142 ld blink,[fp,4]\n\ 143 j.d blink\n\ 144 ld.a fp,[sp,16]\n\ 145"); 146 147/* .fini section end. 148 This must live at the end of the .fini section. */ 149 150asm ("\n\ 151 .section .fini\n\ 152 ld blink,[fp,4]\n\ 153 j.d blink\n\ 154 ld.a fp,[sp,16]\n\ 155"); 156 157#endif /* CRT_FINI */ 158