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
|
// Copyright (C) 2002 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC 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.
// GCC 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 GCC; see the file COPYING. If not, write to
// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301, USA.
// As a special exception, you may use this file as part of a free software
// library without restriction. Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file 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.
// Written by Mark Mitchell, CodeSourcery LLC, <mark@codesourcery.com>
// Thread support written by Jason Merrill, Red Hat Inc. <jason@redhat.com>
#include <bits/c++config.h>
#include <cxxabi.h>
#include <exception>
#include <bits/gthr.h>
#include <bits/atomicity.h>
// The IA64/generic ABI uses the first byte of the guard variable.
// The ARM EABI uses the least significant bit.
// Thread-safe static local initialization support.
#ifdef __GTHREADS
namespace
{
// static_mutex is a single mutex controlling all static initializations.
// This is a static class--the need for a static initialization function
// to pass to __gthread_once precludes creating multiple instances, though
// I suppose you could achieve the same effect with a template.
class static_mutex
{
static __gthread_recursive_mutex_t mutex;
#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
static void init();
#endif
public:
static void lock();
static void unlock();
};
__gthread_recursive_mutex_t static_mutex::mutex
#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT
= __GTHREAD_RECURSIVE_MUTEX_INIT
#endif
;
#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
void static_mutex::init()
{
__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION (&mutex);
}
#endif
void static_mutex::lock()
{
#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
static __gthread_once_t once = __GTHREAD_ONCE_INIT;
__gthread_once (&once, init);
#endif
__gthread_recursive_mutex_lock (&mutex);
}
void static_mutex::unlock ()
{
__gthread_recursive_mutex_unlock (&mutex);
}
}
#ifndef _GLIBCXX_GUARD_TEST_AND_ACQUIRE
inline bool
__test_and_acquire (__cxxabiv1::__guard *g)
{
bool b = _GLIBCXX_GUARD_TEST (g);
_GLIBCXX_READ_MEM_BARRIER;
return b;
}
#define _GLIBCXX_GUARD_TEST_AND_ACQUIRE(G) __test_and_acquire (G)
#endif
#ifndef _GLIBCXX_GUARD_SET_AND_RELEASE
inline void
__set_and_release (__cxxabiv1::__guard *g)
{
_GLIBCXX_WRITE_MEM_BARRIER;
_GLIBCXX_GUARD_SET (g);
}
#define _GLIBCXX_GUARD_SET_AND_RELEASE(G) __set_and_release (G)
#endif
#else /* !__GTHREADS */
#undef _GLIBCXX_GUARD_TEST_AND_ACQUIRE
#undef _GLIBCXX_GUARD_SET_AND_RELEASE
#define _GLIBCXX_GUARD_SET_AND_RELEASE(G) _GLIBCXX_GUARD_SET (G)
#endif /* __GTHREADS */
namespace __gnu_cxx
{
// 6.7[stmt.dcl]/4: If control re-enters the declaration (recursively)
// while the object is being initialized, the behavior is undefined.
// Since we already have a library function to handle locking, we might
// as well check for this situation and throw an exception.
// We use the second byte of the guard variable to remember that we're
// in the middle of an initialization.
class recursive_init: public std::exception
{
public:
recursive_init() throw() { }
virtual ~recursive_init() throw ();
};
recursive_init::~recursive_init() throw() { }
}
namespace __cxxabiv1
{
static inline int
recursion_push (__guard* g)
{
return ((char *)g)[1]++;
}
static inline void
recursion_pop (__guard* g)
{
--((char *)g)[1];
}
static int
acquire_1 (__guard *g)
{
if (_GLIBCXX_GUARD_TEST (g))
return 0;
if (recursion_push (g))
{
#ifdef __EXCEPTIONS
throw __gnu_cxx::recursive_init();
#else
// Use __builtin_trap so we don't require abort().
__builtin_trap ();
#endif
}
return 1;
}
extern "C"
int __cxa_guard_acquire (__guard *g)
{
#ifdef __GTHREADS
// If the target can reorder loads, we need to insert a read memory
// barrier so that accesses to the guarded variable happen after the
// guard test.
if (_GLIBCXX_GUARD_TEST_AND_ACQUIRE (g))
return 0;
if (__gthread_active_p ())
{
// Simple wrapper for exception safety.
struct mutex_wrapper
{
bool unlock;
mutex_wrapper (): unlock(true)
{
static_mutex::lock ();
}
~mutex_wrapper ()
{
if (unlock)
static_mutex::unlock ();
}
} mw;
if (acquire_1 (g))
{
mw.unlock = false;
return 1;
}
return 0;
}
#endif
return acquire_1 (g);
}
extern "C"
void __cxa_guard_abort (__guard *g)
{
recursion_pop (g);
#ifdef __GTHREADS
if (__gthread_active_p ())
static_mutex::unlock ();
#endif
}
extern "C"
void __cxa_guard_release (__guard *g)
{
recursion_pop (g);
_GLIBCXX_GUARD_SET_AND_RELEASE (g);
#ifdef __GTHREADS
if (__gthread_active_p ())
static_mutex::unlock ();
#endif
}
}
|
