6d6babf745
In r369018, Benjamin replaced the custom RWMutex implementation with their C++14 counterpart. Unfortunately, std::shared_timed_mutex is only available on macOS 10.12 and later. This prevents LLVM from compiling even on newer versions of the OS when you have an older deployment target. This patch reintroduced the old RWMutexImpl but guards it by the macOS availability macro. Differential revision: https://reviews.llvm.org/D66313 llvm-svn: 369064
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(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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