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//===-- asan_lock.h ---------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// A wrapper for a simple lock.
//===----------------------------------------------------------------------===//
#ifndef ASAN_LOCK_H
#define ASAN_LOCK_H
#include "asan_internal.h"
// The locks in ASan are global objects and they are never destroyed to avoid
// at-exit races (that is, a lock is being used by other threads while the main
// thread is doing atexit destructors).
#ifdef __APPLE__
#include <pthread.h>
#include <libkern/OSAtomic.h>
namespace __asan {
class AsanLock {
public:
explicit AsanLock(LinkerInitialized) :
mu_(OS_SPINLOCK_INIT),
owner_(0),
is_locked_(false) {}
void Lock() {
CHECK(owner_ != pthread_self());
OSSpinLockLock(&mu_);
is_locked_ = true;
owner_ = pthread_self();
}
void Unlock() {
owner_ = 0;
is_locked_ = false;
OSSpinLockUnlock(&mu_);
}
bool IsLocked() {
// This is not atomic, e.g. one thread may get different values if another
// one is about to release the lock.
return is_locked_;
}
private:
OSSpinLock mu_;
volatile pthread_t owner_; // for debugging purposes
bool is_locked_; // for silly malloc_introspection_t interface
};
} // namespace __asan
#else // assume linux
#include <pthread.h>
namespace __asan {
class AsanLock {
public:
explicit AsanLock(LinkerInitialized) {
// We assume that pthread_mutex_t initialized to all zeroes is a valid
// unlocked mutex. We can not use PTHREAD_MUTEX_INITIALIZER as it triggers
// a gcc warning:
// extended initializer lists only available with -std=c++0x or -std=gnu++0x
}
void Lock() {
pthread_mutex_lock(&mu_);
// pthread_spin_lock(&mu_);
}
void Unlock() {
pthread_mutex_unlock(&mu_);
// pthread_spin_unlock(&mu_);
}
private:
pthread_mutex_t mu_;
// pthread_spinlock_t mu_;
};
} // namespace __asan
#endif
namespace __asan {
class ScopedLock {
public:
explicit ScopedLock(AsanLock *mu) : mu_(mu) {
mu_->Lock();
}
~ScopedLock() {
mu_->Unlock();
}
private:
AsanLock *mu_;
};
} // namespace __asan
#endif // ASAN_LOCK_H
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