1 //===-- Support/MutexGuard.h - Acquire/Release Mutex In Scope ---*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines a guard for a block of code that ensures a Mutex is locked 11 // upon construction and released upon destruction. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_SUPPORT_MUTEXGUARD_H 16 #define LLVM_SUPPORT_MUTEXGUARD_H 17 18 #include "llvm/Support/Mutex.h" 19 20 namespace llvm { 21 /// Instances of this class acquire a given Mutex Lock when constructed and 22 /// hold that lock until destruction. The intention is to instantiate one of 23 /// these on the stack at the top of some scope to be assured that C++ 24 /// destruction of the object will always release the Mutex and thus avoid 25 /// a host of nasty multi-threading problems in the face of exceptions, etc. 26 /// @brief Guard a section of code with a Mutex. 27 class MutexGuard { 28 sys::Mutex &M; 29 MutexGuard(const MutexGuard &); // DO NOT IMPLEMENT 30 void operator=(const MutexGuard &); // DO NOT IMPLEMENT 31 public: 32 MutexGuard(sys::Mutex &m) : M(m) { M.acquire(); } 33 ~MutexGuard() { M.release(); } 34 /// holds - Returns true if this locker instance holds the specified lock. 35 /// This is mostly used in assertions to validate that the correct mutex 36 /// is held. 37 bool holds(const sys::Mutex& lock) const { return &M == &lock; } 38 }; 39 } 40 41 #endif // LLVM_SUPPORT_MUTEXGUARD_H 42
