1 // Copyright (C) 2012-2015 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 #ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
29 #define WIN32_LEAN_AND_MEAN
30 #include <windows.h>
31 #endif
32
33 #if _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL
34
35 extern "C" int __cxa_thread_atexit_impl (void (*func) (void *),
36 void *arg, void *d);
37 extern "C" int
__cxa_thread_atexit(void (* dtor)(void *),void * obj,void * dso_handle)38 __cxxabiv1::__cxa_thread_atexit (void (*dtor)(void *),
39 void *obj, void *dso_handle)
40 _GLIBCXX_NOTHROW
41 {
42 return __cxa_thread_atexit_impl (dtor, obj, dso_handle);
43 }
44
45 #else /* _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL */
46
47 namespace {
48 // One element in a singly-linked stack of cleanups.
49 struct elt
50 {
51 void (*destructor)(void *);
52 void *object;
53 elt *next;
54 #ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
55 HMODULE dll;
56 #endif
57 };
58
59 // Keep a per-thread list of cleanups in gthread_key storage.
60 __gthread_key_t key;
61 // But also support non-threaded mode.
62 elt *single_thread;
63
64 // Run the specified stack of cleanups.
run(void * p)65 void run (void *p)
66 {
67 elt *e = static_cast<elt*>(p);
68 while (e)
69 {
70 elt *old_e = e;
71 e->destructor (e->object);
72 #ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
73 /* Decrement DLL count */
74 if (e->dll)
75 FreeLibrary (e->dll);
76 #endif
77 e = e->next;
78 delete (old_e);
79 }
80 }
81
82 // Run the stack of cleanups for the current thread.
run()83 void run ()
84 {
85 void *e;
86 if (__gthread_active_p ())
87 {
88 e = __gthread_getspecific (key);
89 __gthread_setspecific (key, NULL);
90 }
91 else
92 {
93 e = single_thread;
94 single_thread = NULL;
95 }
96 run (e);
97 }
98
99 // Initialize the key for the cleanup stack. We use a static local for
100 // key init/delete rather than atexit so that delete is run on dlclose.
key_init()101 void key_init() {
102 struct key_s {
103 key_s() { __gthread_key_create (&key, run); }
104 ~key_s() { __gthread_key_delete (key); }
105 };
106 static key_s ks;
107 // Also make sure the destructors are run by std::exit.
108 // FIXME TLS cleanups should run before static cleanups and atexit
109 // cleanups.
110 std::atexit (run);
111 }
112 }
113
114 extern "C" int
__cxa_thread_atexit(void (* dtor)(void *),void * obj,void *)115 __cxxabiv1::__cxa_thread_atexit (void (*dtor)(void *), void *obj, void */*dso_handle*/)
116 _GLIBCXX_NOTHROW
117 {
118 // Do this initialization once.
119 if (__gthread_active_p ())
120 {
121 // When threads are active use __gthread_once.
122 static __gthread_once_t once = __GTHREAD_ONCE_INIT;
123 __gthread_once (&once, key_init);
124 }
125 else
126 {
127 // And when threads aren't active use a static local guard.
128 static bool queued;
129 if (!queued)
130 {
131 queued = true;
132 std::atexit (run);
133 }
134 }
135
136 elt *first;
137 if (__gthread_active_p ())
138 first = static_cast<elt*>(__gthread_getspecific (key));
139 else
140 first = single_thread;
141
142 elt *new_elt = new (std::nothrow) elt;
143 if (!new_elt)
144 return -1;
145 new_elt->destructor = dtor;
146 new_elt->object = obj;
147 new_elt->next = first;
148 #ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
149 /* Store the DLL address for a later call to FreeLibrary in new_elt and
150 increment DLL load count. This blocks the unloading of the DLL
151 before the thread-local dtors have been called. This does NOT help
152 if FreeLibrary/dlclose is called in excess. */
153 GetModuleHandleExW (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
154 (LPCWSTR) dtor, &new_elt->dll);
155 #endif
156
157 if (__gthread_active_p ())
158 __gthread_setspecific (key, new_elt);
159 else
160 single_thread = new_elt;
161
162 return 0;
163 }
164
165 #endif /* _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL */
166