1 /* Copyright (C) 1999-2020 Free Software Foundation, Inc. 2 3 NOTE: This source is derived from an old version taken from the GNU C 4 Library (glibc). 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 #include <assert.h> 28 #include <stdlib.h> 29 30 #include "exit.h" 31 32 #undef __cxa_atexit 33 34 #define atomic_write_barrier() __asm__ ("eieio" ::: "memory") 35 36 int 37 attribute_hidden 38 __internal_atexit (void (*func) (void *), void *arg, void *d, 39 struct exit_function_list **listp) 40 { 41 struct exit_function *new = __new_exitfn (listp); 42 43 if (new == NULL) 44 return -1; 45 46 #ifdef PTR_MANGLE 47 PTR_MANGLE (func); 48 #endif 49 new->func.cxa.fn = (void (*) (void *, int)) func; 50 new->func.cxa.arg = arg; 51 new->func.cxa.dso_handle = d; 52 atomic_write_barrier (); 53 new->flavor = ef_cxa; 54 return 0; 55 } 56 57 58 /* Register a function to be called by exit or when a shared library 59 is unloaded. This function is only called from code generated by 60 the C++ compiler. */ 61 int 62 __cxa_atexit (void (*func) (void *), void *arg, void *d) 63 { 64 return __internal_atexit (func, arg, d, &__exit_funcs); 65 } 66 INTDEF(__cxa_atexit) 67 68 69 static struct exit_function_list initial; 70 struct exit_function_list *__exit_funcs = &initial; 71 uint64_t __new_exitfn_called; 72 73 struct exit_function * 74 __new_exitfn (struct exit_function_list **listp) 75 { 76 struct exit_function_list *p = NULL; 77 struct exit_function_list *l; 78 struct exit_function *r = NULL; 79 size_t i = 0; 80 81 for (l = *listp; l != NULL; p = l, l = l->next) 82 { 83 for (i = l->idx; i > 0; --i) 84 if (l->fns[i - 1].flavor != ef_free) 85 break; 86 87 if (i > 0) 88 break; 89 90 /* This block is completely unused. */ 91 l->idx = 0; 92 } 93 94 if (l == NULL || i == sizeof (l->fns) / sizeof (l->fns[0])) 95 { 96 /* The last entry in a block is used. Use the first entry in 97 the previous block if it exists. Otherwise create a new one. */ 98 if (p == NULL) 99 { 100 assert (l != NULL); 101 p = (struct exit_function_list *) 102 calloc (1, sizeof (struct exit_function_list)); 103 if (p != NULL) 104 { 105 p->next = *listp; 106 *listp = p; 107 } 108 } 109 110 if (p != NULL) 111 { 112 r = &p->fns[0]; 113 p->idx = 1; 114 } 115 } 116 else 117 { 118 /* There is more room in the block. */ 119 r = &l->fns[i]; 120 l->idx = i + 1; 121 } 122 123 /* Mark entry as used, but we don't know the flavor now. */ 124 if (r != NULL) 125 { 126 r->flavor = ef_us; 127 ++__new_exitfn_called; 128 } 129 130 return r; 131 } 132