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# 1 : : // Copyright (c) 2009-2010 Satoshi Nakamoto # 2 : : // Copyright (c) 2009-2020 The Bitcoin Core developers # 3 : : // Distributed under the MIT software license, see the accompanying # 4 : : // file COPYING or http://www.opensource.org/licenses/mit-license.php. # 5 : : # 6 : : #ifndef BITCOIN_THREADSAFETY_H # 7 : : #define BITCOIN_THREADSAFETY_H # 8 : : # 9 : : #include <mutex> # 10 : : # 11 : : #ifdef __clang__ # 12 : : // TL;DR Add GUARDED_BY(mutex) to member variables. The others are # 13 : : // rarely necessary. Ex: int nFoo GUARDED_BY(cs_foo); # 14 : : // # 15 : : // See https://clang.llvm.org/docs/ThreadSafetyAnalysis.html # 16 : : // for documentation. The clang compiler can do advanced static analysis # 17 : : // of locking when given the -Wthread-safety option. # 18 : : #define LOCKABLE __attribute__((lockable)) # 19 : : #define SCOPED_LOCKABLE __attribute__((scoped_lockable)) # 20 : : #define GUARDED_BY(x) __attribute__((guarded_by(x))) # 21 : : #define PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x))) # 22 : : #define ACQUIRED_AFTER(...) __attribute__((acquired_after(__VA_ARGS__))) # 23 : : #define ACQUIRED_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__))) # 24 : : #define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__))) # 25 : : #define SHARED_LOCK_FUNCTION(...) __attribute__((shared_lock_function(__VA_ARGS__))) # 26 : : #define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((exclusive_trylock_function(__VA_ARGS__))) # 27 : : #define SHARED_TRYLOCK_FUNCTION(...) __attribute__((shared_trylock_function(__VA_ARGS__))) # 28 : : #define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__))) # 29 : : #define LOCK_RETURNED(x) __attribute__((lock_returned(x))) # 30 : : #define LOCKS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__))) # 31 : : #define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__))) # 32 : : #define SHARED_LOCKS_REQUIRED(...) __attribute__((shared_locks_required(__VA_ARGS__))) # 33 : : #define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis)) # 34 : : #define ASSERT_EXCLUSIVE_LOCK(...) __attribute__((assert_exclusive_lock(__VA_ARGS__))) # 35 : : #else # 36 : : #define LOCKABLE # 37 : : #define SCOPED_LOCKABLE # 38 : : #define GUARDED_BY(x) # 39 : : #define PT_GUARDED_BY(x) # 40 : : #define ACQUIRED_AFTER(...) # 41 : : #define ACQUIRED_BEFORE(...) # 42 : : #define EXCLUSIVE_LOCK_FUNCTION(...) # 43 : : #define SHARED_LOCK_FUNCTION(...) # 44 : : #define EXCLUSIVE_TRYLOCK_FUNCTION(...) # 45 : : #define SHARED_TRYLOCK_FUNCTION(...) # 46 : : #define UNLOCK_FUNCTION(...) # 47 : : #define LOCK_RETURNED(x) # 48 : : #define LOCKS_EXCLUDED(...) # 49 : : #define EXCLUSIVE_LOCKS_REQUIRED(...) # 50 : : #define SHARED_LOCKS_REQUIRED(...) # 51 : : #define NO_THREAD_SAFETY_ANALYSIS # 52 : : #define ASSERT_EXCLUSIVE_LOCK(...) # 53 : : #endif // __GNUC__ # 54 : : # 55 : : // StdMutex provides an annotated version of std::mutex for us, # 56 : : // and should only be used when sync.h Mutex/LOCK/etc are not usable. # 57 : : class LOCKABLE StdMutex : public std::mutex # 58 : : { # 59 : : public: # 60 : : #ifdef __clang__ # 61 : : //! For negative capabilities in the Clang Thread Safety Analysis. # 62 : : //! A negative requirement uses the EXCLUSIVE_LOCKS_REQUIRED attribute, in conjunction # 63 : : //! with the ! operator, to indicate that a mutex should not be held. # 64 : 0 : const StdMutex& operator!() const { return *this; } # 65 : : #endif // __clang__ # 66 : : }; # 67 : : # 68 : : // StdLockGuard provides an annotated version of std::lock_guard for us, # 69 : : // and should only be used when sync.h Mutex/LOCK/etc are not usable. # 70 : : class SCOPED_LOCKABLE StdLockGuard : public std::lock_guard<StdMutex> # 71 : : { # 72 : : public: # 73 : 5500707 : explicit StdLockGuard(StdMutex& cs) EXCLUSIVE_LOCK_FUNCTION(cs) : std::lock_guard<StdMutex>(cs) {} # 74 : 5500999 : ~StdLockGuard() UNLOCK_FUNCTION() {} # 75 : : }; # 76 : : # 77 : : #endif // BITCOIN_THREADSAFETY_H