1 // Copyright (C) 2012-2013 Free Software Foundation, Inc.
2 //
3 // This file is part of GCC.
4 //
5 // GCC is free software; you can redistribute it and/or modify
6 // it under the terms of the GNU General Public License as published by
7 // the Free Software Foundation; either version 3, or (at your option)
8 // any later version.
9
10 // GCC is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 // GNU General Public License for more details.
14
15 // Under Section 7 of GPL version 3, you are granted additional
16 // permissions described in the GCC Runtime Library Exception, version
17 // 3.1, as published by the Free Software Foundation.
18
19 // You should have received a copy of the GNU General Public License and
20 // a copy of the GCC Runtime Library Exception along with this program;
21 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
22 // <http://www.gnu.org/licenses/>.
23
24 #include <cxxabi.h>
25 #include <cstdlib>
26 #include <new>
27 #include "bits/gthr.h"
28
29 #if HAVE___CXA_THREAD_ATEXIT_IMPL
30
31 extern "C" int __cxa_thread_atexit_impl (void (*func) (void *),
32 void *arg, void *d);
33 extern "C" int
__cxa_thread_atexit(void (* dtor)(void *),void * obj,void * dso_handle)34 __cxxabiv1::__cxa_thread_atexit (void (*dtor)(void *),
35 void *obj, void *dso_handle)
36 _GLIBCXX_NOTHROW
37 {
38 return __cxa_thread_atexit_impl (dtor, obj, dso_handle);
39 }
40
41 #else /* HAVE___CXA_THREAD_ATEXIT_IMPL */
42
43 namespace {
44 // One element in a singly-linked stack of cleanups.
45 struct elt
46 {
47 void (*destructor)(void *);
48 void *object;
49 elt *next;
50 };
51
52 // Keep a per-thread list of cleanups in gthread_key storage.
53 __gthread_key_t key;
54 // But also support non-threaded mode.
55 elt *single_thread;
56
57 // Run the specified stack of cleanups.
run(void * p)58 void run (void *p)
59 {
60 elt *e = static_cast<elt*>(p);
61 for (; e; e = e->next)
62 e->destructor (e->object);
63 }
64
65 // Run the stack of cleanups for the current thread.
run()66 void run ()
67 {
68 void *e;
69 if (__gthread_active_p ())
70 e = __gthread_getspecific (key);
71 else
72 e = single_thread;
73 run (e);
74 }
75
76 // Initialize the key for the cleanup stack. We use a static local for
77 // key init/delete rather than atexit so that delete is run on dlclose.
key_init()78 void key_init() {
79 struct key_s {
80 key_s() { __gthread_key_create (&key, run); }
81 ~key_s() { __gthread_key_delete (key); }
82 };
83 static key_s ks;
84 // Also make sure the destructors are run by std::exit.
85 // FIXME TLS cleanups should run before static cleanups and atexit
86 // cleanups.
87 std::atexit (run);
88 }
89 }
90
91 extern "C" int
__cxa_thread_atexit(void (* dtor)(void *),void * obj,void *)92 __cxxabiv1::__cxa_thread_atexit (void (*dtor)(void *), void *obj, void */*dso_handle*/)
93 _GLIBCXX_NOTHROW
94 {
95 // Do this initialization once.
96 if (__gthread_active_p ())
97 {
98 // When threads are active use __gthread_once.
99 static __gthread_once_t once = __GTHREAD_ONCE_INIT;
100 __gthread_once (&once, key_init);
101 }
102 else
103 {
104 // And when threads aren't active use a static local guard.
105 static bool queued;
106 if (!queued)
107 {
108 queued = true;
109 std::atexit (run);
110 }
111 }
112
113 elt *first;
114 if (__gthread_active_p ())
115 first = static_cast<elt*>(__gthread_getspecific (key));
116 else
117 first = single_thread;
118
119 elt *new_elt = new (std::nothrow) elt;
120 if (!new_elt)
121 return -1;
122 new_elt->destructor = dtor;
123 new_elt->object = obj;
124 new_elt->next = first;
125
126 if (__gthread_active_p ())
127 __gthread_setspecific (key, new_elt);
128 else
129 single_thread = new_elt;
130
131 return 0;
132 }
133
134 #endif /* HAVE___CXA_THREAD_ATEXIT_IMPL */
135