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[/] [open8_urisc/] [trunk/] [gnu/] [binutils/] [gold/] [workqueue-threads.cc] - Rev 241
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// workqueue-threads.cc -- the threaded workqueue for gold // Copyright 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. // This file holds the workqueue implementation which may be used when // using threads. #include "gold.h" #ifdef ENABLE_THREADS #include <cstring> #include <pthread.h> #include "debug.h" #include "gold-threads.h" #include "workqueue.h" #include "workqueue-internal.h" namespace gold { // Class Workqueue_thread represents a single thread. Creating an // instance of this spawns a new thread. class Workqueue_thread { public: Workqueue_thread(Workqueue_threader_threadpool*, int thread_number); ~Workqueue_thread(); private: // This class can not be copied. Workqueue_thread(const Workqueue_thread&); Workqueue_thread& operator=(const Workqueue_thread&); // Check for error from a pthread function. void check(const char* function, int err) const; // A function to pass to pthread_create. This is called with a // pointer to an instance of this object. static void* thread_body(void*); // A pointer to the threadpool that this thread is part of. Workqueue_threader_threadpool* threadpool_; // The thread number. int thread_number_; // The thread ID. pthread_t tid_; }; // Create the thread in the constructor. Workqueue_thread::Workqueue_thread(Workqueue_threader_threadpool* threadpool, int thread_number) : threadpool_(threadpool), thread_number_(thread_number) { pthread_attr_t attr; int err = pthread_attr_init(&attr); this->check("pthread_attr_init", err); err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); this->check("pthread_attr_setdetachstate", err); err = pthread_create(&this->tid_, &attr, &Workqueue_thread::thread_body, reinterpret_cast<void*>(this)); this->check("pthread_create", err); err = pthread_attr_destroy(&attr); this->check("pthread_attr_destroy", err); } // The destructor will be called when the thread is exiting. Workqueue_thread::~Workqueue_thread() { } // Check for an error. void Workqueue_thread::check(const char* function, int err) const { if (err != 0) gold_fatal(_("%s failed: %s"), function, strerror(err)); } // Passed to pthread_create. extern "C" void* Workqueue_thread::thread_body(void* arg) { Workqueue_thread* pwt = reinterpret_cast<Workqueue_thread*>(arg); pwt->threadpool_->process(pwt->thread_number_); // Delete the thread object as we exit. delete pwt; return NULL; } // Class Workqueue_threader_threadpool. // Constructor. Workqueue_threader_threadpool::Workqueue_threader_threadpool( Workqueue* workqueue) : Workqueue_threader(workqueue), check_thread_count_(0), lock_(), desired_thread_count_(1), threads_(1) { } // Destructor. Workqueue_threader_threadpool::~Workqueue_threader_threadpool() { // Tell the threads to exit. this->get_workqueue()->set_thread_count(0); } // Set the thread count. void Workqueue_threader_threadpool::set_thread_count(int thread_count) { int create; { Hold_lock hl(this->lock_); this->desired_thread_count_ = thread_count; create = this->desired_thread_count_ - this->threads_; if (create < 0) this->check_thread_count_ = 1; } if (create > 0) { for (int i = 0; i < create; ++i) { // Note that threads delete themselves when they exit, so we // don't keep pointers to them. new Workqueue_thread(this, this->threads_); ++this->threads_; } } } // Return whether the current thread should be cancelled. bool Workqueue_threader_threadpool::should_cancel_thread(int thread_number) { // Fast exit without taking a lock. if (!this->check_thread_count_) return false; { Hold_lock hl(this->lock_); if (thread_number > this->desired_thread_count_) { --this->threads_; if (this->threads_ <= this->desired_thread_count_) this->check_thread_count_ = 0; return true; } } return false; } } // End namespace gold. #endif // defined(ENABLE_THREADS)
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