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b25bb36a | 1 | /* Implementation of W32-specific threads compatibility routines for |
43f3a59d | 2 | libgcc2. */ |
b25bb36a | 3 | |
8d9254fc | 4 | /* Copyright (C) 1999-2020 Free Software Foundation, Inc. |
b25bb36a DS |
5 | Contributed by Mumit Khan <khan@xraylith.wisc.edu>. |
6 | Modified and moved to separate file by Danny Smith | |
7 | <dannysmith@users.sourceforge.net>. | |
8 | ||
9 | This file is part of GCC. | |
10 | ||
11 | GCC is free software; you can redistribute it and/or modify it under | |
12 | the terms of the GNU General Public License as published by the Free | |
748086b7 | 13 | Software Foundation; either version 3, or (at your option) any later |
b25bb36a DS |
14 | version. |
15 | ||
16 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
17 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
18 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
19 | for more details. | |
20 | ||
748086b7 JJ |
21 | Under Section 7 of GPL version 3, you are granted additional |
22 | permissions described in the GCC Runtime Library Exception, version | |
23 | 3.1, as published by the Free Software Foundation. | |
b25bb36a | 24 | |
748086b7 JJ |
25 | You should have received a copy of the GNU General Public License and |
26 | a copy of the GCC Runtime Library Exception along with this program; | |
27 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
28 | <http://www.gnu.org/licenses/>. */ | |
b25bb36a | 29 | |
42dfcf84 | 30 | #include <windows.h> |
b25bb36a | 31 | #ifndef __GTHREAD_HIDE_WIN32API |
4fab535e | 32 | # define __GTHREAD_HIDE_WIN32API 1 |
b25bb36a | 33 | #endif |
42dfcf84 WY |
34 | #undef __GTHREAD_I486_INLINE_LOCK_PRIMITIVES |
35 | #define __GTHREAD_I486_INLINE_LOCK_PRIMITIVES | |
5d1c8e77 | 36 | #include "gthr-win32.h" |
b25bb36a DS |
37 | |
38 | /* Windows32 threads specific definitions. The windows32 threading model | |
39 | does not map well into pthread-inspired gcc's threading model, and so | |
40 | there are caveats one needs to be aware of. | |
41 | ||
42 | 1. The destructor supplied to __gthread_key_create is ignored for | |
43 | generic x86-win32 ports. This will certainly cause memory leaks | |
44 | due to unreclaimed eh contexts (sizeof (eh_context) is at least | |
45 | 24 bytes for x86 currently). | |
46 | ||
47 | This memory leak may be significant for long-running applications | |
48 | that make heavy use of C++ EH. | |
49 | ||
50 | However, Mingw runtime (version 0.3 or newer) provides a mechanism | |
51 | to emulate pthreads key dtors; the runtime provides a special DLL, | |
52 | linked in if -mthreads option is specified, that runs the dtors in | |
53 | the reverse order of registration when each thread exits. If | |
54 | -mthreads option is not given, a stub is linked in instead of the | |
55 | DLL, which results in memory leak. Other x86-win32 ports can use | |
56 | the same technique of course to avoid the leak. | |
57 | ||
58 | 2. The error codes returned are non-POSIX like, and cast into ints. | |
59 | This may cause incorrect error return due to truncation values on | |
60 | hw where sizeof (DWORD) > sizeof (int). | |
61 | ||
80408cac WY |
62 | 3. We are currently using a special mutex instead of the Critical |
63 | Sections, since Win9x does not support TryEnterCriticalSection | |
64 | (while NT does). | |
b25bb36a DS |
65 | |
66 | The basic framework should work well enough. In the long term, GCC | |
67 | needs to use Structured Exception Handling on Windows32. */ | |
68 | ||
69 | int | |
70 | __gthr_win32_once (__gthread_once_t *once, void (*func) (void)) | |
71 | { | |
72 | if (once == NULL || func == NULL) | |
73 | return EINVAL; | |
74 | ||
75 | if (! once->done) | |
76 | { | |
77 | if (InterlockedIncrement (&(once->started)) == 0) | |
78 | { | |
79 | (*func) (); | |
80 | once->done = TRUE; | |
81 | } | |
82 | else | |
83 | { | |
84 | /* Another thread is currently executing the code, so wait for it | |
85 | to finish; yield the CPU in the meantime. If performance | |
86 | does become an issue, the solution is to use an Event that | |
87 | we wait on here (and set above), but that implies a place to | |
88 | create the event before this routine is called. */ | |
89 | while (! once->done) | |
90 | Sleep (0); | |
91 | } | |
92 | } | |
93 | return 0; | |
94 | } | |
95 | ||
96 | /* Windows32 thread local keys don't support destructors; this leads to | |
97 | leaks, especially in threaded applications making extensive use of | |
98 | C++ EH. Mingw uses a thread-support DLL to work-around this problem. */ | |
99 | ||
100 | int | |
ccf8e764 RH |
101 | __gthr_win32_key_create (__gthread_key_t *key, |
102 | void (*dtor) (void *) __attribute__((unused))) | |
b25bb36a DS |
103 | { |
104 | int status = 0; | |
105 | DWORD tls_index = TlsAlloc (); | |
106 | if (tls_index != 0xFFFFFFFF) | |
107 | { | |
108 | *key = tls_index; | |
109 | #ifdef MINGW32_SUPPORTS_MT_EH | |
110 | /* Mingw runtime will run the dtors in reverse order for each thread | |
111 | when the thread exits. */ | |
112 | status = __mingwthr_key_dtor (*key, dtor); | |
113 | #endif | |
114 | } | |
115 | else | |
116 | status = (int) GetLastError (); | |
117 | return status; | |
118 | } | |
119 | ||
120 | int | |
121 | __gthr_win32_key_delete (__gthread_key_t key) | |
122 | { | |
123 | return (TlsFree (key) != 0) ? 0 : (int) GetLastError (); | |
124 | } | |
125 | ||
126 | void * | |
127 | __gthr_win32_getspecific (__gthread_key_t key) | |
128 | { | |
129 | DWORD lasterror; | |
130 | void *ptr; | |
131 | lasterror = GetLastError(); | |
132 | ptr = TlsGetValue(key); | |
133 | SetLastError( lasterror ); | |
134 | return ptr; | |
135 | } | |
136 | ||
137 | int | |
138 | __gthr_win32_setspecific (__gthread_key_t key, const void *ptr) | |
139 | { | |
9e2af376 AL |
140 | if (TlsSetValue (key, CONST_CAST2(void *, const void *, ptr)) != 0) |
141 | return 0; | |
142 | else | |
143 | return GetLastError (); | |
b25bb36a DS |
144 | } |
145 | ||
146 | void | |
147 | __gthr_win32_mutex_init_function (__gthread_mutex_t *mutex) | |
148 | { | |
42dfcf84 | 149 | mutex->counter = -1; |
dff717d2 | 150 | mutex->sema = CreateSemaphoreW (NULL, 0, 65535, NULL); |
b25bb36a DS |
151 | } |
152 | ||
c262f705 DS |
153 | void |
154 | __gthr_win32_mutex_destroy (__gthread_mutex_t *mutex) | |
155 | { | |
156 | CloseHandle ((HANDLE) mutex->sema); | |
157 | } | |
158 | ||
b25bb36a DS |
159 | int |
160 | __gthr_win32_mutex_lock (__gthread_mutex_t *mutex) | |
161 | { | |
42dfcf84 | 162 | if (InterlockedIncrement (&mutex->counter) == 0 || |
80408cac | 163 | WaitForSingleObject (mutex->sema, INFINITE) == WAIT_OBJECT_0) |
b25bb36a DS |
164 | return 0; |
165 | else | |
80408cac | 166 | { |
42dfcf84 WY |
167 | /* WaitForSingleObject returns WAIT_FAILED, and we can only do |
168 | some best-effort cleanup here. */ | |
80408cac WY |
169 | InterlockedDecrement (&mutex->counter); |
170 | return 1; | |
171 | } | |
b25bb36a DS |
172 | } |
173 | ||
174 | int | |
175 | __gthr_win32_mutex_trylock (__gthread_mutex_t *mutex) | |
176 | { | |
42dfcf84 | 177 | if (__GTHR_W32_InterlockedCompareExchange (&mutex->counter, 0, -1) < 0) |
b25bb36a DS |
178 | return 0; |
179 | else | |
180 | return 1; | |
181 | } | |
182 | ||
183 | int | |
184 | __gthr_win32_mutex_unlock (__gthread_mutex_t *mutex) | |
185 | { | |
42dfcf84 | 186 | if (InterlockedDecrement (&mutex->counter) >= 0) |
80408cac WY |
187 | return ReleaseSemaphore (mutex->sema, 1, NULL) ? 0 : 1; |
188 | else | |
189 | return 0; | |
b25bb36a | 190 | } |
40aac948 JM |
191 | |
192 | void | |
193 | __gthr_win32_recursive_mutex_init_function (__gthread_recursive_mutex_t *mutex) | |
194 | { | |
195 | mutex->counter = -1; | |
196 | mutex->depth = 0; | |
197 | mutex->owner = 0; | |
dff717d2 | 198 | mutex->sema = CreateSemaphoreW (NULL, 0, 65535, NULL); |
40aac948 JM |
199 | } |
200 | ||
201 | int | |
202 | __gthr_win32_recursive_mutex_lock (__gthread_recursive_mutex_t *mutex) | |
203 | { | |
204 | DWORD me = GetCurrentThreadId(); | |
205 | if (InterlockedIncrement (&mutex->counter) == 0) | |
206 | { | |
207 | mutex->depth = 1; | |
208 | mutex->owner = me; | |
209 | } | |
210 | else if (mutex->owner == me) | |
211 | { | |
40219f96 | 212 | InterlockedDecrement (&mutex->counter); |
40aac948 JM |
213 | ++(mutex->depth); |
214 | } | |
215 | else if (WaitForSingleObject (mutex->sema, INFINITE) == WAIT_OBJECT_0) | |
216 | { | |
217 | mutex->depth = 1; | |
218 | mutex->owner = me; | |
219 | } | |
220 | else | |
221 | { | |
222 | /* WaitForSingleObject returns WAIT_FAILED, and we can only do | |
223 | some best-effort cleanup here. */ | |
224 | InterlockedDecrement (&mutex->counter); | |
225 | return 1; | |
226 | } | |
227 | return 0; | |
228 | } | |
229 | ||
230 | int | |
231 | __gthr_win32_recursive_mutex_trylock (__gthread_recursive_mutex_t *mutex) | |
232 | { | |
233 | DWORD me = GetCurrentThreadId(); | |
234 | if (__GTHR_W32_InterlockedCompareExchange (&mutex->counter, 0, -1) < 0) | |
235 | { | |
236 | mutex->depth = 1; | |
237 | mutex->owner = me; | |
238 | } | |
239 | else if (mutex->owner == me) | |
240 | ++(mutex->depth); | |
241 | else | |
242 | return 1; | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
247 | int | |
248 | __gthr_win32_recursive_mutex_unlock (__gthread_recursive_mutex_t *mutex) | |
249 | { | |
250 | --(mutex->depth); | |
251 | if (mutex->depth == 0) | |
252 | { | |
253 | mutex->owner = 0; | |
254 | ||
255 | if (InterlockedDecrement (&mutex->counter) >= 0) | |
256 | return ReleaseSemaphore (mutex->sema, 1, NULL) ? 0 : 1; | |
257 | } | |
258 | ||
259 | return 0; | |
260 | } | |
1504e3e1 JW |
261 | |
262 | int | |
263 | __gthr_win32_recursive_mutex_destroy (__gthread_recursive_mutex_t *mutex) | |
264 | { | |
265 | CloseHandle ((HANDLE) mutex->sema); | |
266 | return 0; | |
267 | } |