| //===- ThreadSafety.h ------------------------------------------*- C++ --*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // |
| // A intra-procedural analysis for thread safety (e.g. deadlocks and race |
| // conditions), based off of an annotation system. |
| // |
| // See http://clang.llvm.org/docs/LanguageExtensions.html#threadsafety for more |
| // information. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_THREADSAFETY_H |
| #define LLVM_CLANG_THREADSAFETY_H |
| |
| #include "clang/Analysis/AnalysisContext.h" |
| #include "clang/Basic/SourceLocation.h" |
| #include "llvm/ADT/StringRef.h" |
| |
| namespace clang { |
| namespace thread_safety { |
| |
| /// This enum distinguishes between different kinds of operations that may |
| /// need to be protected by locks. We use this enum in error handling. |
| enum ProtectedOperationKind { |
| POK_VarDereference, /// Dereferencing a variable (e.g. p in *p = 5;) |
| POK_VarAccess, /// Reading or writing a variable (e.g. x in x = 5;) |
| POK_FunctionCall /// Making a function call (e.g. fool()) |
| }; |
| |
| /// This enum distinguishes between different kinds of lock actions. For |
| /// example, it is an error to write a variable protected by shared version of a |
| /// mutex. |
| enum LockKind { |
| LK_Shared, /// Shared/reader lock of a mutex |
| LK_Exclusive /// Exclusive/writer lock of a mutex |
| }; |
| |
| /// This enum distinguishes between different ways to access (read or write) a |
| /// variable. |
| enum AccessKind { |
| AK_Read, /// Reading a variable |
| AK_Written /// Writing a variable |
| }; |
| |
| /// This enum distinguishes between different situations where we warn due to |
| /// inconsistent locking. |
| /// \enum SK_LockedSomeLoopIterations -- a mutex is locked for some but not all |
| /// loop iterations. |
| /// \enum SK_LockedSomePredecessors -- a mutex is locked in some but not all |
| /// predecessors of a CFGBlock. |
| /// \enum SK_LockedAtEndOfFunction -- a mutex is still locked at the end of a |
| /// function. |
| enum LockErrorKind { |
| LEK_LockedSomeLoopIterations, |
| LEK_LockedSomePredecessors, |
| LEK_LockedAtEndOfFunction |
| }; |
| |
| /// Handler class for thread safety warnings. |
| class ThreadSafetyHandler { |
| public: |
| typedef llvm::StringRef Name; |
| virtual ~ThreadSafetyHandler(); |
| |
| /// Warn about lock expressions which fail to resolve to lockable objects. |
| /// \param Loc -- the SourceLocation of the unresolved expression. |
| virtual void handleInvalidLockExp(SourceLocation Loc) {} |
| |
| /// Warn about unlock function calls that do not have a prior matching lock |
| /// expression. |
| /// \param LockName -- A StringRef name for the lock expression, to be printed |
| /// in the error message. |
| /// \param Loc -- The SourceLocation of the Unlock |
| virtual void handleUnmatchedUnlock(Name LockName, SourceLocation Loc) {} |
| |
| /// Warn about lock function calls for locks which are already held. |
| /// \param LockName -- A StringRef name for the lock expression, to be printed |
| /// in the error message. |
| /// \param Loc -- The location of the second lock expression. |
| virtual void handleDoubleLock(Name LockName, SourceLocation Loc) {} |
| |
| /// Warn about situations where a mutex is sometimes held and sometimes not. |
| /// The three situations are: |
| /// 1. a mutex is locked on an "if" branch but not the "else" branch, |
| /// 2, or a mutex is only held at the start of some loop iterations, |
| /// 3. or when a mutex is locked but not unlocked inside a function. |
| /// \param LockName -- A StringRef name for the lock expression, to be printed |
| /// in the error message. |
| /// \param LocLocked -- The location of the lock expression where the mutex is |
| /// locked |
| /// \param LocEndOfScope -- The location of the end of the scope where the |
| /// mutex is no longer held |
| /// \param LEK -- which of the three above cases we should warn for |
| virtual void handleMutexHeldEndOfScope(Name LockName, |
| SourceLocation LocLocked, |
| SourceLocation LocEndOfScope, |
| LockErrorKind LEK){} |
| |
| /// Warn when a mutex is held exclusively and shared at the same point. For |
| /// example, if a mutex is locked exclusively during an if branch and shared |
| /// during the else branch. |
| /// \param LockName -- A StringRef name for the lock expression, to be printed |
| /// in the error message. |
| /// \param Loc1 -- The location of the first lock expression. |
| /// \param Loc2 -- The location of the second lock expression. |
| virtual void handleExclusiveAndShared(Name LockName, SourceLocation Loc1, |
| SourceLocation Loc2) {} |
| |
| /// Warn when a protected operation occurs while no locks are held. |
| /// \param D -- The decl for the protected variable or function |
| /// \param POK -- The kind of protected operation (e.g. variable access) |
| /// \param AK -- The kind of access (i.e. read or write) that occurred |
| /// \param Loc -- The location of the protected operation. |
| virtual void handleNoMutexHeld(const NamedDecl *D, ProtectedOperationKind POK, |
| AccessKind AK, SourceLocation Loc) {} |
| |
| /// Warn when a protected operation occurs while the specific mutex protecting |
| /// the operation is not locked. |
| /// \param D -- The decl for the protected variable or function |
| /// \param POK -- The kind of protected operation (e.g. variable access) |
| /// \param LockName -- A StringRef name for the lock expression, to be printed |
| /// in the error message. |
| /// \param LK -- The kind of access (i.e. read or write) that occurred |
| /// \param Loc -- The location of the protected operation. |
| virtual void handleMutexNotHeld(const NamedDecl *D, |
| ProtectedOperationKind POK, Name LockName, |
| LockKind LK, SourceLocation Loc) {} |
| |
| /// Warn when a function is called while an excluded mutex is locked. For |
| /// example, the mutex may be locked inside the function. |
| /// \param FunName -- The name of the function |
| /// \param LockName -- A StringRef name for the lock expression, to be printed |
| /// in the error message. |
| /// \param Loc -- The location of the function call. |
| virtual void handleFunExcludesLock(Name FunName, Name LockName, |
| SourceLocation Loc) {} |
| }; |
| |
| /// \brief Check a function's CFG for thread-safety violations. |
| /// |
| /// We traverse the blocks in the CFG, compute the set of mutexes that are held |
| /// at the end of each block, and issue warnings for thread safety violations. |
| /// Each block in the CFG is traversed exactly once. |
| void runThreadSafetyAnalysis(AnalysisDeclContext &AC, |
| ThreadSafetyHandler &Handler); |
| |
| /// \brief Helper function that returns a LockKind required for the given level |
| /// of access. |
| LockKind getLockKindFromAccessKind(AccessKind AK); |
| |
| }} // end namespace clang::thread_safety |
| #endif |