1/* Copyright (C) 1999-2015 Free Software Foundation, Inc.
2
3   NOTE: This source is derived from an old version taken from the GNU C
4   Library (glibc).
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 3, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16for more details.
17
18Under Section 7 of GPL version 3, you are granted additional
19permissions described in the GCC Runtime Library Exception, version
203.1, as published by the Free Software Foundation.
21
22You should have received a copy of the GNU General Public License and
23a copy of the GCC Runtime Library Exception along with this program;
24see 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
36int
37attribute_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.  */
61int
62__cxa_atexit (void (*func) (void *), void *arg, void *d)
63{
64  return __internal_atexit (func, arg, d, &__exit_funcs);
65}
66INTDEF(__cxa_atexit)
67
68
69static struct exit_function_list initial;
70struct exit_function_list *__exit_funcs = &initial;
71uint64_t __new_exitfn_called;
72
73struct 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