137 lines
3.2 KiB
C++
137 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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#if defined(LLVM_USE_RW_MUTEX_IMPL)
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using namespace llvm;
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using namespace sys;
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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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RWMutexImpl::RWMutexImpl() = default;
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RWMutexImpl::~RWMutexImpl() = default;
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bool RWMutexImpl::lock_shared() { return true; }
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bool RWMutexImpl::unlock_shared() { return true; }
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bool RWMutexImpl::lock() { return true; }
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bool RWMutexImpl::unlock() { 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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// 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::lock_shared()
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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::unlock_shared()
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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::lock()
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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::unlock()
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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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#else
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RWMutexImpl::RWMutexImpl() : data_(new MutexImpl(false)) { }
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RWMutexImpl::~RWMutexImpl() {
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delete static_cast<MutexImpl *>(data_);
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}
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bool RWMutexImpl::lock_shared() {
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return static_cast<MutexImpl *>(data_)->acquire();
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}
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bool RWMutexImpl::unlock_shared() {
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return static_cast<MutexImpl *>(data_)->release();
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}
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bool RWMutexImpl::lock() {
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return static_cast<MutexImpl *>(data_)->acquire();
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}
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bool RWMutexImpl::unlock() {
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return static_cast<MutexImpl *>(data_)->release();
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}
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#endif
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#endif
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#endif
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