1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/* Threads compatibily routines for libgcc2. */
/* Compile this one with gcc. */
/* Copyright (C) 1999, 2000 Free Software Foundation, Inc.
Contributed by Mumit Khan <khan@xraylith.wisc.edu>.
This file is part of GNU CC.
GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* As a special exception, if you link this library with other files,
some of which are compiled with GCC, to produce an executable,
this library does not by itself cause the resulting executable
to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why
the executable file might be covered by the GNU General Public License. */
#ifndef __gthr_win32_h
#define __gthr_win32_h
/* Windows32 threads specific definitions. The windows32 threading model
does not map well into pthread-inspired gcc's threading model, and so
there are caveats one needs to be aware of.
1. The destructor supplied to __gthread_key_create is ignored for
generic x86-win32 ports. This will certainly cause memory leaks
due to unreclaimed eh contexts (sizeof (eh_context) is at least
24 bytes for x86 currently).
This memory leak may be significant for long-running applications
that make heavy use of C++ EH.
However, Mingw runtime (version 0.3 or newer) provides a mechanism
to emulate pthreads key dtors; the runtime provides a special DLL,
linked in if -mthreads option is specified, that runs the dtors in
the reverse order of registration when each thread exits. If
-mthreads option is not given, a stub is linked in instead of the
DLL, which results in memory leak. Other x86-win32 ports can use
the same technique of course to avoid the leak.
2. The error codes returned are non-POSIX like, and cast into ints.
This may cause incorrect error return due to truncation values on
hw where sizeof (DWORD) > sizeof (int).
3. We might consider using Critical Sections instead of Windows32
mutexes for better performance, but emulating __gthread_mutex_trylock
interface becomes more complicated (Win9x does not support
TryEnterCriticalSectioni, while NT does).
The basic framework should work well enough. In the long term, GCC
needs to use Structured Exception Handling on Windows32. */
#define __GTHREADS 1
#include <windows.h>
#include <errno.h>
#ifdef __MINGW32__
#include <_mingw.h>
#endif
typedef DWORD __gthread_key_t;
typedef struct {
int done;
long started;
} __gthread_once_t;
typedef HANDLE __gthread_mutex_t;
#define __GTHREAD_ONCE_INIT {FALSE, -1}
#define __GTHREAD_MUTEX_INIT_FUNCTION __gthread_mutex_init_function
#if __MINGW32_MAJOR_VERSION >= 1 || \
(__MINGW32_MAJOR_VERSION == 0 && __MINGW32_MINOR_VERSION > 2)
#define MINGW32_SUPPORTS_MT_EH 1
extern int __mingwthr_key_dtor PROTO((DWORD, void (*) (void *)));
/* Mingw runtime >= v0.3 provides a magic variable that is set to non-zero
if -mthreads option was specified, or 0 otherwise. This is to get around
the lack of weak symbols in PE-COFF. */
extern int _CRT_MT;
#endif
static inline int
__gthread_active_p ()
{
#ifdef MINGW32_SUPPORTS_MT_EH
return _CRT_MT;
#else
return 1;
#endif
}
static inline int
__gthread_once (__gthread_once_t *once, void (*func) ())
{
if (! __gthread_active_p ())
return -1;
else if (once == NULL || func == NULL)
return EINVAL;
if (! once->done)
{
if (InterlockedIncrement (&(once->started)) == 0)
{
(*func) ();
once->done = TRUE;
}
else
{
/* Another thread is currently executing the code, so wait for it
to finish; yield the CPU in the meantime. If performance
does become an issue, the solution is to use an Event that
we wait on here (and set above), but that implies a place to
create the event before this routine is called. */
while (! once->done)
Sleep (0);
}
}
return 0;
}
/* Windows32 thread local keys don't support destructors; this leads to
leaks, especially in threaded applications making extensive use of
C++ EH. Mingw uses a thread-support DLL to work-around this problem. */
static inline int
__gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
{
int status = 0;
DWORD tls_index = TlsAlloc ();
if (tls_index != 0xFFFFFFFF)
{
*key = tls_index;
#ifdef MINGW32_SUPPORTS_MT_EH
/* Mingw runtime will run the dtors in reverse order for each thread
when the thread exits. */
status = __mingwthr_key_dtor (*key, dtor);
#endif
}
else
status = (int) GetLastError ();
return status;
}
/* Currently, this routine is called only for Mingw runtime, and if
-mthreads option is chosen to link in the thread support DLL. */
static inline int
__gthread_key_dtor (__gthread_key_t key, void *ptr)
{
/* Nothing needed. */
return 0;
}
static inline int
__gthread_key_delete (__gthread_key_t key)
{
return (TlsFree (key) != 0) ? 0 : (int) GetLastError ();
}
static inline void *
__gthread_getspecific (__gthread_key_t key)
{
return TlsGetValue (key);
}
static inline int
__gthread_setspecific (__gthread_key_t key, const void *ptr)
{
return (TlsSetValue (key, (void*) ptr) != 0) ? 0 : (int) GetLastError ();
}
static inline void
__gthread_mutex_init_function (__gthread_mutex_t *mutex)
{
/* Create unnamed mutex with default security attr and no initial owner. */
*mutex = CreateMutex (NULL, 0, NULL);
}
static inline int
__gthread_mutex_lock (__gthread_mutex_t *mutex)
{
int status = 0;
if (__gthread_active_p ())
{
if (WaitForSingleObject (*mutex, INFINITE) == WAIT_OBJECT_0)
status = 0;
else
status = 1;
}
return status;
}
static inline int
__gthread_mutex_trylock (__gthread_mutex_t *mutex)
{
int status = 0;
if (__gthread_active_p ())
{
if (WaitForSingleObject (*mutex, 0) == WAIT_OBJECT_0)
status = 0;
else
status = 1;
}
return status;
}
static inline int
__gthread_mutex_unlock (__gthread_mutex_t *mutex)
{
if (__gthread_active_p ())
return (ReleaseMutex (*mutex) != 0) ? 0 : 1;
else
return 0;
}
#endif /* not __gthr_win32_h */
|
