Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Support/MutexGuard.h
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//===-- Support/MutexGuard.h - Acquire/Release Mutex In Scope ---*- 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 defines a guard for a block of code that ensures a Mutex is locked
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// upon construction and released upon destruction.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_MUTEXGUARD_H
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#define LLVM_SUPPORT_MUTEXGUARD_H
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#include "llvm/Support/Mutex.h"
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namespace llvm {
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  /// Instances of this class acquire a given Mutex Lock when constructed and
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  /// hold that lock until destruction. The intention is to instantiate one of
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  /// these on the stack at the top of some scope to be assured that C++
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  /// destruction of the object will always release the Mutex and thus avoid
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  /// a host of nasty multi-threading problems in the face of exceptions, etc.
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  /// Guard a section of code with a Mutex.
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  class MutexGuard {
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    sys::Mutex &M;
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    MutexGuard(const MutexGuard &) = delete;
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    void operator=(const MutexGuard &) = delete;
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  public:
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    MutexGuard(sys::Mutex &m) : M(m) { M.lock(); }
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    ~MutexGuard() { M.unlock(); }
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    /// holds - Returns true if this locker instance holds the specified lock.
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    /// This is mostly used in assertions to validate that the correct mutex
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    /// is held.
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    bool holds(const sys::Mutex& lock) const { return &M == &lock; }
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  };
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}
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#endif // LLVM_SUPPORT_MUTEXGUARD_H