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to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
125 lines
3.2 KiB
C++
125 lines
3.2 KiB
C++
//===- RWMutex.cpp - Reader/Writer Mutual Exclusion Lock --------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the llvm::sys::RWMutex class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/RWMutex.h"
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#include "llvm/Config/config.h"
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only TRULY operating system
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//=== independent code.
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//===----------------------------------------------------------------------===//
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#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0
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// Define all methods as no-ops if threading is explicitly disabled
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using namespace llvm;
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using namespace sys;
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RWMutexImpl::RWMutexImpl() = default;
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RWMutexImpl::~RWMutexImpl() = default;
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bool RWMutexImpl::reader_acquire() { return true; }
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bool RWMutexImpl::reader_release() { return true; }
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bool RWMutexImpl::writer_acquire() { return true; }
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bool RWMutexImpl::writer_release() { return true; }
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#else
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#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_RWLOCK_INIT)
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#include <cassert>
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#include <cstdlib>
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#include <pthread.h>
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using namespace llvm;
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using namespace sys;
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// Construct a RWMutex using pthread calls
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RWMutexImpl::RWMutexImpl()
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{
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// Declare the pthread_rwlock data structures
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pthread_rwlock_t* rwlock =
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static_cast<pthread_rwlock_t*>(safe_malloc(sizeof(pthread_rwlock_t)));
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#ifdef __APPLE__
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// Workaround a bug/mis-feature in Darwin's pthread_rwlock_init.
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bzero(rwlock, sizeof(pthread_rwlock_t));
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#endif
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// Initialize the rwlock
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int errorcode = pthread_rwlock_init(rwlock, nullptr);
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(void)errorcode;
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assert(errorcode == 0);
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// Assign the data member
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data_ = rwlock;
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}
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// Destruct a RWMutex
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RWMutexImpl::~RWMutexImpl()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != nullptr);
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pthread_rwlock_destroy(rwlock);
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free(rwlock);
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}
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bool
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RWMutexImpl::reader_acquire()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != nullptr);
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int errorcode = pthread_rwlock_rdlock(rwlock);
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return errorcode == 0;
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}
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bool
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RWMutexImpl::reader_release()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != nullptr);
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int errorcode = pthread_rwlock_unlock(rwlock);
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return errorcode == 0;
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}
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bool
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RWMutexImpl::writer_acquire()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != nullptr);
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int errorcode = pthread_rwlock_wrlock(rwlock);
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return errorcode == 0;
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}
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bool
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RWMutexImpl::writer_release()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != nullptr);
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int errorcode = pthread_rwlock_unlock(rwlock);
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return errorcode == 0;
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}
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#elif defined(LLVM_ON_UNIX)
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#include "Unix/RWMutex.inc"
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#elif defined( _WIN32)
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#include "Windows/RWMutex.inc"
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#else
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#warning Neither LLVM_ON_UNIX nor _WIN32 was set in Support/Mutex.cpp
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#endif
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#endif
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