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//===-- sanitizer_mutex.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 ThreadSanitizer/AddressSanitizer runtime.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_MUTEX_H
#define SANITIZER_MUTEX_H
#include "sanitizer_atomic.h"
#include "sanitizer_internal_defs.h"
#include "sanitizer_libc.h"
namespace __sanitizer {
class StaticSpinMutex {
public:
void Init() {
atomic_store(&state_, 0, memory_order_relaxed);
}
void Lock() {
if (TryLock())
return;
LockSlow();
}
bool TryLock() {
return atomic_exchange(&state_, 1, memory_order_acquire) == 0;
}
void Unlock() {
atomic_store(&state_, 0, memory_order_release);
}
private:
atomic_uint8_t state_;
void NOINLINE LockSlow() {
for (int i = 0;; i++) {
if (i < 10)
proc_yield(10);
else
internal_sched_yield();
if (atomic_load(&state_, memory_order_relaxed) == 0
&& atomic_exchange(&state_, 1, memory_order_acquire) == 0)
return;
}
}
};
class SpinMutex : public StaticSpinMutex {
public:
SpinMutex() {
Init();
}
private:
SpinMutex(const SpinMutex&);
void operator=(const SpinMutex&);
};
class BlockingMutex {
public:
explicit BlockingMutex(LinkerInitialized);
void Lock();
void Unlock();
private:
uptr opaque_storage_[10];
};
template<typename MutexType>
class GenericScopedLock {
public:
explicit GenericScopedLock(MutexType *mu)
: mu_(mu) {
mu_->Lock();
}
~GenericScopedLock() {
mu_->Unlock();
}
private:
MutexType *mu_;
GenericScopedLock(const GenericScopedLock&);
void operator=(const GenericScopedLock&);
};
template<typename MutexType>
class GenericScopedReadLock {
public:
explicit GenericScopedReadLock(MutexType *mu)
: mu_(mu) {
mu_->ReadLock();
}
~GenericScopedReadLock() {
mu_->ReadUnlock();
}
private:
MutexType *mu_;
GenericScopedReadLock(const GenericScopedReadLock&);
void operator=(const GenericScopedReadLock&);
};
typedef GenericScopedLock<StaticSpinMutex> SpinMutexLock;
typedef GenericScopedLock<BlockingMutex> BlockingMutexLock;
} // namespace __sanitizer
#endif // SANITIZER_MUTEX_H
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