1 // gold-threads.h -- thread support for gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 // gold can be configured to support threads. If threads are
24 // supported, the user can specify at runtime whether or not to
25 // support them. This provides an interface to manage locking
29 // A simple lock class.
31 #ifndef GOLD_THREADS_H
32 #define GOLD_THREADS_H
38 class Once_initialize
;
39 class Initialize_lock_once
;
41 // The interface for the implementation of a Lock.
60 // A simple lock class.
72 { this->lock_
->acquire(); }
77 { this->lock_
->release(); }
80 // This class can not be copied.
82 Lock
& operator=(const Lock
&);
87 { return this->lock_
; }
99 { this->lock_
.acquire(); }
102 { this->lock_
.release(); }
105 // This class can not be copied.
106 Hold_lock(const Hold_lock
&);
107 Hold_lock
& operator=(const Hold_lock
&);
112 class Hold_optional_lock
115 Hold_optional_lock(Lock
* lock
)
118 if (this->lock_
!= NULL
)
119 this->lock_
->acquire();
122 ~Hold_optional_lock()
124 if (this->lock_
!= NULL
)
125 this->lock_
->release();
129 Hold_optional_lock(const Hold_optional_lock
&);
130 Hold_optional_lock
& operator=(const Hold_optional_lock
&);
135 // The interface for the implementation of a condition variable.
148 wait(Lock_impl
*) = 0;
157 // A simple condition variable class. It is always associated with a
166 // Wait for the condition variable to be signalled. This should
167 // only be called when the lock is held.
170 { this->condvar_
->wait(this->lock_
.get_impl()); }
172 // Signal the condition variable--wake up at least one thread
173 // waiting on the condition variable. This should only be called
174 // when the lock is held.
177 { this->condvar_
->signal(); }
179 // Broadcast the condition variable--wake up all threads waiting on
180 // the condition variable. This should only be called when the lock
184 { this->condvar_
->broadcast(); }
187 // This class can not be copied.
188 Condvar(const Condvar
&);
189 Condvar
& operator=(const Condvar
&);
192 Condvar_impl
* condvar_
;
195 // A class used to do something once. This is an abstract parent
196 // class; any actual use will involve a child of this.
207 // Call this function to do whatever it is. We pass an argument
208 // even though you have to use a child class because in some uses
209 // setting the argument would itself require a Once class.
213 // This is an internal function, which must be public because it is
214 // run by an extern "C" function called via pthread_once.
216 internal_run(void* arg
);
219 // This must be implemented by the child class.
221 do_run_once(void* arg
) = 0;
224 // True if we have already run the function.
226 // Internal compare-and-swap lock on was_run_;
227 uint32_t was_run_lock_
;
228 // The lock to run the function only once.
229 Once_initialize
* once_
;
232 // A class used to initialize a lock exactly once, after the options
233 // have been read. This is needed because the implementation of locks
234 // depends on whether we've seen the --threads option. Before the
235 // options have been read, we know we are single-threaded, so we can
236 // get by without using a lock. This class should be an instance
237 // variable of the class which has a lock which needs to be
240 class Initialize_lock
: public Once
243 // The class which uses this will have a pointer to a lock. This
244 // must be constructed with a pointer to that pointer.
245 Initialize_lock(Lock
** pplock
)
249 // Initialize the lock. Return true if the lock is now initialized,
250 // false if it is not (because the options have not yet been read).
259 // A pointer to the lock pointer which must be initialized.
260 Lock
** const pplock_
;
263 } // End namespace gold.
265 #endif // !defined(GOLD_THREADS_H)
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