llvm-project/flang/runtime/lock.h

75 lines
1.6 KiB
C++

//===-- runtime/lock.h ------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// Wraps a mutex
#ifndef FORTRAN_RUNTIME_LOCK_H_
#define FORTRAN_RUNTIME_LOCK_H_
#include "terminator.h"
// Avoid <mutex> if possible to avoid introduction of C++ runtime
// library dependence.
#ifndef _WIN32
#define USE_PTHREADS 1
#else
#undef USE_PTHREADS
#endif
#if USE_PTHREADS
#include <pthread.h>
#else
#include <mutex>
#endif
namespace Fortran::runtime {
class Lock {
public:
#if USE_PTHREADS
Lock() { pthread_mutex_init(&mutex_, nullptr); }
~Lock() { pthread_mutex_destroy(&mutex_); }
void Take() {
while (pthread_mutex_lock(&mutex_)) {
}
}
bool Try() { return pthread_mutex_trylock(&mutex_) == 0; }
void Drop() { pthread_mutex_unlock(&mutex_); }
#else
void Take() { mutex_.lock(); }
bool Try() { return mutex_.try_lock(); }
void Drop() { mutex_.unlock(); }
#endif
void CheckLocked(const Terminator &terminator) {
if (Try()) {
Drop();
terminator.Crash("Lock::CheckLocked() failed");
}
}
private:
#if USE_PTHREADS
pthread_mutex_t mutex_{};
#else
std::mutex mutex_;
#endif
};
class CriticalSection {
public:
explicit CriticalSection(Lock &lock) : lock_{lock} { lock_.Take(); }
~CriticalSection() { lock_.Drop(); }
private:
Lock &lock_;
};
} // namespace Fortran::runtime
#endif // FORTRAN_RUNTIME_LOCK_H_