Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Support/Mutex.h
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//===- llvm/Support/Mutex.h - Mutex Operating System Concept -----*- 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 declares the llvm::sys::Mutex class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_MUTEX_H
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#define LLVM_SUPPORT_MUTEX_H
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#include "llvm/Config/llvm-config.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Threading.h"
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#include <cassert>
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namespace llvm
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{
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  namespace sys
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  {
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    /// Platform agnostic Mutex class.
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    class MutexImpl
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    {
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    /// @name Constructors
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    /// @{
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    public:
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      /// Initializes the lock but doesn't acquire it. if \p recursive is set
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      /// to false, the lock will not be recursive which makes it cheaper but
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      /// also more likely to deadlock (same thread can't acquire more than
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      /// once).
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      /// Default Constructor.
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      explicit MutexImpl(bool recursive = true);
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      /// Releases and removes the lock
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      /// Destructor
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      ~MutexImpl();
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    /// @}
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    /// @name Methods
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    /// @{
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    public:
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      /// Attempts to unconditionally acquire the lock. If the lock is held by
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      /// another thread, this method will wait until it can acquire the lock.
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      /// @returns false if any kind of error occurs, true otherwise.
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      /// Unconditionally acquire the lock.
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      bool acquire();
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      /// Attempts to release the lock. If the lock is held by the current
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      /// thread, the lock is released allowing other threads to acquire the
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      /// lock.
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      /// @returns false if any kind of error occurs, true otherwise.
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      /// Unconditionally release the lock.
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      bool release();
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      /// Attempts to acquire the lock without blocking. If the lock is not
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      /// available, this function returns false quickly (without blocking). If
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      /// the lock is available, it is acquired.
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      /// @returns false if any kind of error occurs or the lock is not
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      /// available, true otherwise.
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      /// Try to acquire the lock.
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      bool tryacquire();
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    //@}
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    /// @name Platform Dependent Data
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    /// @{
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    private:
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#if defined(LLVM_ENABLE_THREADS) && LLVM_ENABLE_THREADS != 0
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      void* data_; ///< We don't know what the data will be
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#endif
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    /// @}
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    /// @name Do Not Implement
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    /// @{
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    private:
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      MutexImpl(const MutexImpl &) = delete;
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      void operator=(const MutexImpl &) = delete;
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    /// @}
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    };
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    /// SmartMutex - A mutex with a compile time constant parameter that
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    /// indicates whether this mutex should become a no-op when we're not
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    /// running in multithreaded mode.
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    template<bool mt_only>
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    class SmartMutex {
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      MutexImpl impl;
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      unsigned acquired;
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      bool recursive;
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    public:
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      explicit SmartMutex(bool rec = true) :
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        impl(rec), acquired(0), recursive(rec) { }
llvm::sys::SmartMutex<false>::SmartMutex(bool)
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        impl(rec), acquired(0), recursive(rec) { }
llvm::sys::SmartMutex<true>::SmartMutex(bool)
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        impl(rec), acquired(0), recursive(rec) { }
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      bool lock() {
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        if (!mt_only || 
llvm_is_multithreaded()664k
) {
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          return impl.acquire();
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        } else {
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          // Single-threaded debugging code.  This would be racy in
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          // multithreaded mode, but provides not sanity checks in single
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          // threaded mode.
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          assert((recursive || acquired == 0) && "Lock already acquired!!");
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          ++acquired;
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          return true;
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        }
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      }
llvm::sys::SmartMutex<false>::lock()
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      bool lock() {
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        if (!mt_only || 
llvm_is_multithreaded()0
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          return impl.acquire();
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        } else {
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          // Single-threaded debugging code.  This would be racy in
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          // multithreaded mode, but provides not sanity checks in single
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          // threaded mode.
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          assert((recursive || acquired == 0) && "Lock already acquired!!");
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          ++acquired;
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          return true;
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        }
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      }
llvm::sys::SmartMutex<true>::lock()
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      bool lock() {
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        if (!mt_only || llvm_is_multithreaded()) {
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          return impl.acquire();
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        } else {
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          // Single-threaded debugging code.  This would be racy in
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          // multithreaded mode, but provides not sanity checks in single
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          // threaded mode.
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          assert((recursive || acquired == 0) && "Lock already acquired!!");
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          ++acquired;
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          return true;
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        }
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      }
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      bool unlock() {
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        if (!mt_only || 
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) {
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          return impl.release();
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        } else {
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          // Single-threaded debugging code.  This would be racy in
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          // multithreaded mode, but provides not sanity checks in single
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          // threaded mode.
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          assert(((recursive && acquired) || (acquired == 1)) &&
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                 "Lock not acquired before release!");
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          --acquired;
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          return true;
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        }
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      }
llvm::sys::SmartMutex<false>::unlock()
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      bool unlock() {
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        if (!mt_only || 
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          return impl.release();
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        } else {
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          // Single-threaded debugging code.  This would be racy in
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          // multithreaded mode, but provides not sanity checks in single
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          // threaded mode.
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          assert(((recursive && acquired) || (acquired == 1)) &&
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                 "Lock not acquired before release!");
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          --acquired;
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          return true;
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        }
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      }
llvm::sys::SmartMutex<true>::unlock()
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      bool unlock() {
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        if (!mt_only || llvm_is_multithreaded()) {
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          return impl.release();
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        } else {
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          // Single-threaded debugging code.  This would be racy in
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          // multithreaded mode, but provides not sanity checks in single
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          // threaded mode.
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          assert(((recursive && acquired) || (acquired == 1)) &&
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                 "Lock not acquired before release!");
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          --acquired;
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          return true;
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        }
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      }
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      bool try_lock() {
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        if (!mt_only || llvm_is_multithreaded())
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          return impl.tryacquire();
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        else return true;
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      }
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      private:
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        SmartMutex(const SmartMutex<mt_only> & original);
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        void operator=(const SmartMutex<mt_only> &);
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    };
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    /// Mutex - A standard, always enforced mutex.
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    typedef SmartMutex<false> Mutex;
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    template<bool mt_only>
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    class SmartScopedLock  {
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      SmartMutex<mt_only>& mtx;
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    public:
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      SmartScopedLock(SmartMutex<mt_only>& m) : mtx(m) {
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        mtx.lock();
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      }
llvm::sys::SmartScopedLock<true>::SmartScopedLock(llvm::sys::SmartMutex<true>&)
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      SmartScopedLock(SmartMutex<mt_only>& m) : mtx(m) {
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        mtx.lock();
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      }
llvm::sys::SmartScopedLock<false>::SmartScopedLock(llvm::sys::SmartMutex<false>&)
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      SmartScopedLock(SmartMutex<mt_only>& m) : mtx(m) {
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        mtx.lock();
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      }
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      ~SmartScopedLock() {
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        mtx.unlock();
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      }
llvm::sys::SmartScopedLock<true>::~SmartScopedLock()
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      ~SmartScopedLock() {
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        mtx.unlock();
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      }
llvm::sys::SmartScopedLock<false>::~SmartScopedLock()
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      ~SmartScopedLock() {
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        mtx.unlock();
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      }
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    };
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    typedef SmartScopedLock<false> ScopedLock;
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  }
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}
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#endif