//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Reid Spencer and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#ifndef LLVM_SYSTEM_MUTEX_H
#define LLVM_SYSTEM_MUTEX_H
+#include "llvm/System/Threading.h"
+#include <cassert>
+
namespace llvm
{
namespace sys
{
/// @brief Platform agnostic Mutex class.
- class Mutex
+ class MutexImpl
{
/// @name Constructors
/// @{
/// also more likely to deadlock (same thread can't acquire more than
/// once).
/// @brief Default Constructor.
- Mutex ( bool recursive = true );
+ explicit MutexImpl(bool recursive = true);
/// Releases and removes the lock
/// @brief Destructor
- ~Mutex ( void );
+ ~MutexImpl();
/// @}
/// @name Methods
/// lock.
/// @returns false if any kind of error occurs, true otherwise.
/// @brief Unconditionally release the lock.
- bool release(void);
+ bool release();
/// Attempts to acquire the lock without blocking. If the lock is not
/// available, this function returns false quickly (without blocking). If
/// @name Platform Dependent Data
/// @{
private:
-#ifdef ENABLE_THREADS
void* data_; ///< We don't know what the data will be
-#endif
/// @}
/// @name Do Not Implement
/// @{
private:
- Mutex(const Mutex & original);
- void operator=(const Mutex &);
+ MutexImpl(const MutexImpl & original);
+ void operator=(const MutexImpl &);
/// @}
};
+
+
+ /// SmartMutex - A mutex with a compile time constant parameter that
+ /// indicates whether this mutex should become a no-op when we're not
+ /// running in multithreaded mode.
+ template<bool mt_only>
+ class SmartMutex : public MutexImpl {
+ unsigned acquired;
+ bool recursive;
+ public:
+ explicit SmartMutex(bool rec = true) :
+ MutexImpl(rec), acquired(0), recursive(rec) { }
+
+ bool acquire() {
+ if (!mt_only || llvm_is_multithreaded())
+ return MutexImpl::acquire();
+
+ // Single-threaded debugging code. This would be racy in multithreaded
+ // mode, but provides not sanity checks in single threaded mode.
+ assert((recursive || acquired == 0) && "Lock already acquired!!");
+ ++acquired;
+ return true;
+ }
+
+ bool release() {
+ if (!mt_only || llvm_is_multithreaded())
+ return MutexImpl::release();
+
+ // Single-threaded debugging code. This would be racy in multithreaded
+ // mode, but provides not sanity checks in single threaded mode.
+ assert(((recursive && acquired) || (acquired == 1)) &&
+ "Lock not acquired before release!");
+ --acquired;
+ return true;
+ }
+
+ bool tryacquire() {
+ if (!mt_only || llvm_is_multithreaded())
+ return MutexImpl::tryacquire();
+ return true;
+ }
+
+ private:
+ SmartMutex(const SmartMutex<mt_only> & original);
+ void operator=(const SmartMutex<mt_only> &);
+ };
+
+ /// Mutex - A standard, always enforced mutex.
+ typedef SmartMutex<false> Mutex;
+
+ template<bool mt_only>
+ class SmartScopedLock {
+ SmartMutex<mt_only>* mtx;
+
+ public:
+ SmartScopedLock(SmartMutex<mt_only>* m) : mtx(m) {
+ mtx->acquire();
+ }
+
+ ~SmartScopedLock() {
+ mtx->release();
+ }
+ };
+
+ typedef SmartScopedLock<false> ScopedLock;
}
}