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[/] [openrisc/] [trunk/] [gnu-src/] [binutils-2.20.1/] [gold/] [gold-threads.cc] - Rev 447
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// gold-threads.cc -- thread support for gold // Copyright 2006, 2007, 2008 Free Software Foundation, Inc. // Written by Ian Lance Taylor <iant@google.com>. // This file is part of gold. // This program 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 3 of the License, or // (at your option) any later version. // This program 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 this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, // MA 02110-1301, USA. #include "gold.h" #include <cstring> #ifdef ENABLE_THREADS #include <pthread.h> #endif #include "options.h" #include "parameters.h" #include "gold-threads.h" namespace gold { class Condvar_impl_nothreads; // The non-threaded version of Lock_impl. class Lock_impl_nothreads : public Lock_impl { public: Lock_impl_nothreads() : acquired_(false) { } ~Lock_impl_nothreads() { gold_assert(!this->acquired_); } void acquire() { gold_assert(!this->acquired_); this->acquired_ = true; } void release() { gold_assert(this->acquired_); this->acquired_ = false; } private: friend class Condvar_impl_nothreads; bool acquired_; }; #ifdef ENABLE_THREADS class Condvar_impl_threads; // The threaded version of Lock_impl. class Lock_impl_threads : public Lock_impl { public: Lock_impl_threads(); ~Lock_impl_threads(); void acquire(); void release(); private: // This class can not be copied. Lock_impl_threads(const Lock_impl_threads&); Lock_impl_threads& operator=(const Lock_impl_threads&); friend class Condvar_impl_threads; pthread_mutex_t mutex_; }; Lock_impl_threads::Lock_impl_threads() { pthread_mutexattr_t attr; int err = pthread_mutexattr_init(&attr); if (err != 0) gold_fatal(_("pthead_mutextattr_init failed: %s"), strerror(err)); #ifdef PTHREAD_MUTEXT_ADAPTIVE_NP err = pthread_mutextattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP); if (err != 0) gold_fatal(_("pthread_mutextattr_settype failed: %s"), strerror(err)); #endif err = pthread_mutex_init (&this->mutex_, &attr); if (err != 0) gold_fatal(_("pthread_mutex_init failed: %s"), strerror(err)); err = pthread_mutexattr_destroy(&attr); if (err != 0) gold_fatal(_("pthread_mutexattr_destroy failed: %s"), strerror(err)); } Lock_impl_threads::~Lock_impl_threads() { int err = pthread_mutex_destroy(&this->mutex_); if (err != 0) gold_fatal(_("pthread_mutex_destroy failed: %s"), strerror(err)); } void Lock_impl_threads::acquire() { int err = pthread_mutex_lock(&this->mutex_); if (err != 0) gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err)); } void Lock_impl_threads::release() { int err = pthread_mutex_unlock(&this->mutex_); if (err != 0) gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err)); } #endif // defined(ENABLE_THREADS) // Class Lock. Lock::Lock() { if (!parameters->options().threads()) this->lock_ = new Lock_impl_nothreads; else { #ifdef ENABLE_THREADS this->lock_ = new Lock_impl_threads; #else gold_unreachable(); #endif } } Lock::~Lock() { delete this->lock_; } // The non-threaded version of Condvar_impl. class Condvar_impl_nothreads : public Condvar_impl { public: Condvar_impl_nothreads() { } ~Condvar_impl_nothreads() { } void wait(Lock_impl* li) { gold_assert(static_cast<Lock_impl_nothreads*>(li)->acquired_); } void signal() { } void broadcast() { } }; #ifdef ENABLE_THREADS // The threaded version of Condvar_impl. class Condvar_impl_threads : public Condvar_impl { public: Condvar_impl_threads(); ~Condvar_impl_threads(); void wait(Lock_impl*); void signal(); void broadcast(); private: // This class can not be copied. Condvar_impl_threads(const Condvar_impl_threads&); Condvar_impl_threads& operator=(const Condvar_impl_threads&); pthread_cond_t cond_; }; Condvar_impl_threads::Condvar_impl_threads() { int err = pthread_cond_init(&this->cond_, NULL); if (err != 0) gold_fatal(_("pthread_cond_init failed: %s"), strerror(err)); } Condvar_impl_threads::~Condvar_impl_threads() { int err = pthread_cond_destroy(&this->cond_); if (err != 0) gold_fatal(_("pthread_cond_destroy failed: %s"), strerror(err)); } void Condvar_impl_threads::wait(Lock_impl* li) { Lock_impl_threads* lit = static_cast<Lock_impl_threads*>(li); int err = pthread_cond_wait(&this->cond_, &lit->mutex_); if (err != 0) gold_fatal(_("pthread_cond_wait failed: %s"), strerror(err)); } void Condvar_impl_threads::signal() { int err = pthread_cond_signal(&this->cond_); if (err != 0) gold_fatal(_("pthread_cond_signal failed: %s"), strerror(err)); } void Condvar_impl_threads::broadcast() { int err = pthread_cond_broadcast(&this->cond_); if (err != 0) gold_fatal(_("pthread_cond_broadcast failed: %s"), strerror(err)); } #endif // defined(ENABLE_THREADS) // Methods for Condvar class. Condvar::Condvar(Lock& lock) : lock_(lock) { if (!parameters->options().threads()) this->condvar_ = new Condvar_impl_nothreads; else { #ifdef ENABLE_THREADS this->condvar_ = new Condvar_impl_threads; #else gold_unreachable(); #endif } } Condvar::~Condvar() { delete this->condvar_; } #ifdef ENABLE_THREADS // Class Initialize_lock_once. This exists to hold a pthread_once_t // structure for Initialize_lock. class Initialize_lock_once { public: Initialize_lock_once() : once_(PTHREAD_ONCE_INIT) { } // Return a pointer to the pthread_once_t variable. pthread_once_t* once_control() { return &this->once_; } private: pthread_once_t once_; }; #endif // !defined(ENABLE_THREADS) #ifdef ENABLE_THREADS // A single lock which controls access to initialize_lock_pointer. // This is used because we can't pass parameters to functions passed // to pthread_once. static pthread_mutex_t initialize_lock_control = PTHREAD_MUTEX_INITIALIZER; // A pointer to a pointer to the lock which we need to initialize // once. Access to this is controlled by initialize_lock_control. static Lock** initialize_lock_pointer; // A routine passed to pthread_once which initializes the lock which // initialize_lock_pointer points to. extern "C" { static void initialize_lock_once() { *initialize_lock_pointer = new Lock(); } } #endif // !defined(ENABLE_THREADS) // Class Initialize_lock. Initialize_lock::Initialize_lock(Lock** pplock) : pplock_(pplock) { #ifndef ENABLE_THREADS this->once_ = NULL; #else this->once_ = new Initialize_lock_once(); #endif } // Initialize the lock. bool Initialize_lock::initialize() { // If the lock has already been initialized, we don't need to do // anything. Note that this assumes that the pointer value will be // set completely or not at all. I hope this is always safe. We // want to do this for efficiency. if (*this->pplock_ != NULL) return true; // We can't initialize the lock until we have read the options. if (!parameters->options_valid()) return false; // If the user did not use --threads, then we can initialize // directly. if (!parameters->options().threads()) { *this->pplock_ = new Lock(); return true; } #ifndef ENABLE_THREADS // If there is no threads support, we don't need to use // pthread_once. *this->pplock_ = new Lock(); #else // !defined(ENABLE_THREADS) // Since we can't pass parameters to routines called by // pthread_once, we use a static variable: initialize_lock_pointer. // That in turns means that we need to use a mutex to control access // to initialize_lock_pointer. int err = pthread_mutex_lock(&initialize_lock_control); if (err != 0) gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err)); initialize_lock_pointer = this->pplock_; err = pthread_once(this->once_->once_control(), initialize_lock_once); if (err != 0) gold_fatal(_("pthread_once failed: %s"), strerror(err)); initialize_lock_pointer = NULL; err = pthread_mutex_unlock(&initialize_lock_control); if (err != 0) gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err)); gold_assert(*this->pplock_ != NULL); #endif // !defined(ENABLE_THREADS) return true; } } // End namespace gold.
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