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[/] [open8_urisc/] [trunk/] [gnu/] [binutils/] [gold/] [gold-threads.cc] - Blame information for rev 53

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// gold-threads.cc -- thread support for gold
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// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#include <cstring>
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#ifdef ENABLE_THREADS
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#include <pthread.h>
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#endif
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#include "options.h"
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#include "parameters.h"
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#include "gold-threads.h"
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namespace gold
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{
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class Condvar_impl_nothreads;
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// The non-threaded version of Lock_impl.
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class Lock_impl_nothreads : public Lock_impl
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{
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 public:
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  Lock_impl_nothreads()
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    : acquired_(false)
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  { }
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  ~Lock_impl_nothreads()
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  { gold_assert(!this->acquired_); }
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  void
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  acquire()
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  {
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    gold_assert(!this->acquired_);
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    this->acquired_ = true;
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  }
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  void
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  release()
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  {
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    gold_assert(this->acquired_);
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    this->acquired_ = false;
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  }
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 private:
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  friend class Condvar_impl_nothreads;
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  bool acquired_;
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};
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#ifdef ENABLE_THREADS
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class Condvar_impl_threads;
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// The threaded version of Lock_impl.
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class Lock_impl_threads : public Lock_impl
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{
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 public:
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  Lock_impl_threads();
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  ~Lock_impl_threads();
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  void acquire();
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  void release();
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private:
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  // This class can not be copied.
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  Lock_impl_threads(const Lock_impl_threads&);
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  Lock_impl_threads& operator=(const Lock_impl_threads&);
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  friend class Condvar_impl_threads;
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  pthread_mutex_t mutex_;
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};
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Lock_impl_threads::Lock_impl_threads()
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{
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  pthread_mutexattr_t attr;
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  int err = pthread_mutexattr_init(&attr);
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  if (err != 0)
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    gold_fatal(_("pthead_mutextattr_init failed: %s"), strerror(err));
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#ifdef PTHREAD_MUTEX_ADAPTIVE_NP
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  err = pthread_mutextattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
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  if (err != 0)
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    gold_fatal(_("pthread_mutextattr_settype failed: %s"), strerror(err));
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#endif
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  err = pthread_mutex_init(&this->mutex_, &attr);
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  if (err != 0)
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    gold_fatal(_("pthread_mutex_init failed: %s"), strerror(err));
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  err = pthread_mutexattr_destroy(&attr);
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  if (err != 0)
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    gold_fatal(_("pthread_mutexattr_destroy failed: %s"), strerror(err));
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}
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119
Lock_impl_threads::~Lock_impl_threads()
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{
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  int err = pthread_mutex_destroy(&this->mutex_);
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  if (err != 0)
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    gold_fatal(_("pthread_mutex_destroy failed: %s"), strerror(err));
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}
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void
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Lock_impl_threads::acquire()
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{
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  int err = pthread_mutex_lock(&this->mutex_);
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  if (err != 0)
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    gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err));
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}
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void
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Lock_impl_threads::release()
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{
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  int err = pthread_mutex_unlock(&this->mutex_);
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  if (err != 0)
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    gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err));
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}
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#endif // defined(ENABLE_THREADS)
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// Class Lock.
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Lock::Lock()
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{
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  if (!parameters->options().threads())
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    this->lock_ = new Lock_impl_nothreads;
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  else
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    {
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#ifdef ENABLE_THREADS
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      this->lock_ = new Lock_impl_threads;
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#else
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      gold_unreachable();
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#endif
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    }
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}
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160
Lock::~Lock()
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{
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  delete this->lock_;
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}
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165
// The non-threaded version of Condvar_impl.
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class Condvar_impl_nothreads : public Condvar_impl
168
{
169
 public:
170
  Condvar_impl_nothreads()
171
  { }
172
 
173
  ~Condvar_impl_nothreads()
174
  { }
175
 
176
  void
177
  wait(Lock_impl* li)
178
  { gold_assert(static_cast<Lock_impl_nothreads*>(li)->acquired_); }
179
 
180
  void
181
  signal()
182
  { }
183
 
184
  void
185
  broadcast()
186
  { }
187
};
188
 
189
#ifdef ENABLE_THREADS
190
 
191
// The threaded version of Condvar_impl.
192
 
193
class Condvar_impl_threads : public Condvar_impl
194
{
195
 public:
196
  Condvar_impl_threads();
197
  ~Condvar_impl_threads();
198
 
199
  void
200
  wait(Lock_impl*);
201
 
202
  void
203
  signal();
204
 
205
  void
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  broadcast();
207
 
208
 private:
209
  // This class can not be copied.
210
  Condvar_impl_threads(const Condvar_impl_threads&);
211
  Condvar_impl_threads& operator=(const Condvar_impl_threads&);
212
 
213
  pthread_cond_t cond_;
214
};
215
 
216
Condvar_impl_threads::Condvar_impl_threads()
217
{
218
  int err = pthread_cond_init(&this->cond_, NULL);
219
  if (err != 0)
220
    gold_fatal(_("pthread_cond_init failed: %s"), strerror(err));
221
}
222
 
223
Condvar_impl_threads::~Condvar_impl_threads()
224
{
225
  int err = pthread_cond_destroy(&this->cond_);
226
  if (err != 0)
227
    gold_fatal(_("pthread_cond_destroy failed: %s"), strerror(err));
228
}
229
 
230
void
231
Condvar_impl_threads::wait(Lock_impl* li)
232
{
233
  Lock_impl_threads* lit = static_cast<Lock_impl_threads*>(li);
234
  int err = pthread_cond_wait(&this->cond_, &lit->mutex_);
235
  if (err != 0)
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    gold_fatal(_("pthread_cond_wait failed: %s"), strerror(err));
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}
238
 
239
void
240
Condvar_impl_threads::signal()
241
{
242
  int err = pthread_cond_signal(&this->cond_);
243
  if (err != 0)
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    gold_fatal(_("pthread_cond_signal failed: %s"), strerror(err));
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}
246
 
247
void
248
Condvar_impl_threads::broadcast()
249
{
250
  int err = pthread_cond_broadcast(&this->cond_);
251
  if (err != 0)
252
    gold_fatal(_("pthread_cond_broadcast failed: %s"), strerror(err));
253
}
254
 
255
#endif // defined(ENABLE_THREADS)
256
 
257
// Methods for Condvar class.
258
 
259
Condvar::Condvar(Lock& lock)
260
  : lock_(lock)
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{
262
  if (!parameters->options().threads())
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    this->condvar_ = new Condvar_impl_nothreads;
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  else
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    {
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#ifdef ENABLE_THREADS
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      this->condvar_ = new Condvar_impl_threads;
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#else
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      gold_unreachable();
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#endif
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    }
272
}
273
 
274
Condvar::~Condvar()
275
{
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  delete this->condvar_;
277
}
278
 
279
#ifdef ENABLE_THREADS
280
 
281
// Class Once_initialize.  This exists to hold a pthread_once_t
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// structure for Once.
283
 
284
class Once_initialize
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{
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 public:
287
  Once_initialize()
288
    : once_(PTHREAD_ONCE_INIT)
289
  { }
290
 
291
  // Return a pointer to the pthread_once_t variable.
292
  pthread_once_t*
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  once_control()
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  { return &this->once_; }
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296
 private:
297
  pthread_once_t once_;
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};
299
 
300
#endif // defined(ENABLE_THREADS)
301
 
302
#ifdef ENABLE_THREADS
303
 
304
// A single lock which controls access to once_pointer.  This is used
305
// because we can't pass parameters to functions passed to
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// pthread_once.
307
 
308
static pthread_mutex_t once_pointer_control = PTHREAD_MUTEX_INITIALIZER;
309
 
310
// A pointer to Once structure we want to run.  Access to this is
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// controlled by once_pointer_control.
312
 
313
static Once* once_pointer;
314
 
315
// The argument to pass to the Once structure.  Access to this is
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// controlled by once_pointer_control.
317
 
318
static void* once_arg;
319
 
320
// A routine passed to pthread_once which runs the Once pointer.
321
 
322
extern "C"
323
{
324
 
325
static void
326
c_run_once(void)
327
{
328
  once_pointer->internal_run(once_arg);
329
}
330
 
331
}
332
 
333
#endif // defined(ENABLE_THREADS)
334
 
335
// Class Once.
336
 
337
Once::Once()
338
  : was_run_(false), was_run_lock_(0)
339
{
340
#ifndef ENABLE_THREADS
341
  this->once_ = NULL;
342
#else
343
  this->once_ = new Once_initialize();
344
#endif
345
}
346
 
347
// Run the function once.
348
 
349
void
350
Once::run_once(void* arg)
351
{
352
#ifndef ENABLE_THREADS
353
 
354
  // If there is no threads support, we don't need to use pthread_once.
355
  if (!this->was_run_)
356
    this->internal_run(arg);
357
 
358
#else // defined(ENABLE_THREADS)
359
 
360
  if (parameters->options_valid() && !parameters->options().threads())
361
    {
362
      // If we are not using threads, we don't need to lock.
363
      if (!this->was_run_)
364
        this->internal_run(arg);
365
      return;
366
    }
367
 
368
  // If we have the sync builtins, use them to skip the lock if the
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  // value has already been initialized.
370
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
371
  while (true)
372
    {
373
      if (__sync_bool_compare_and_swap(&this->was_run_lock_, 0, 1))
374
        break;
375
    }
376
  bool was_run = this->was_run_;
377
  while (true)
378
    {
379
      if (__sync_bool_compare_and_swap(&this->was_run_lock_, 1, 0))
380
        break;
381
    }
382
  if (was_run)
383
    return;
384
#endif
385
 
386
  // Since we can't pass parameters to routines called by
387
  // pthread_once, we use a static variable: once_pointer.  This in
388
  // turns means that we need to use a mutex to control access to
389
  // once_pointer.
390
 
391
  int err = pthread_mutex_lock(&once_pointer_control);
392
  if (err != 0)
393
    gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err));
394
 
395
  once_pointer = this;
396
  once_arg = arg;
397
 
398
  err = pthread_once(this->once_->once_control(), c_run_once);
399
  if (err != 0)
400
    gold_fatal(_("pthread_once failed: %s"), strerror(err));
401
 
402
  once_pointer = NULL;
403
  once_arg = NULL;
404
 
405
  err = pthread_mutex_unlock(&once_pointer_control);
406
  if (err != 0)
407
    gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err));
408
 
409
#endif // defined(ENABLE_THREADS)
410
}
411
 
412
// Actually run the function in the child class.  This function will
413
// be run only once.
414
 
415
void
416
Once::internal_run(void* arg)
417
{
418
  this->do_run_once(arg);
419
  this->was_run_ = true;
420
}
421
 
422
// Class Initialize_lock.
423
 
424
// Initialize the lock.
425
 
426
bool
427
Initialize_lock::initialize()
428
{
429
  // We can't initialize the lock until we have read the options.
430
  if (!parameters->options_valid())
431
    return false;
432
  else
433
    {
434
      this->run_once(NULL);
435
      return true;
436
    }
437
}
438
 
439
// Initialize the lock exactly once.
440
 
441
void
442
Initialize_lock::do_run_once(void*)
443
{
444
  *this->pplock_ = new Lock();
445
}
446
 
447
} // End namespace gold.

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