Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 1 | //===--- PthreadLockChecker.h - Undefined arguments checker ----*- 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 defines PthreadLockChecker, a simple lock -> unlock checker. Eventually |
| 11 | // this shouldn't be registered with GRExprEngineInternalChecks. |
| 12 | // |
| 13 | //===----------------------------------------------------------------------===// |
| 14 | |
| 15 | #include "clang/Analysis/PathSensitive/CheckerVisitor.h" |
| 16 | #include "clang/Analysis/PathSensitive/BugReporter.h" |
| 17 | #include "clang/Analysis/PathSensitive/GRStateTrait.h" |
| 18 | #include "GRExprEngineExperimentalChecks.h" |
| 19 | #include "llvm/ADT/ImmutableSet.h" |
| 20 | |
| 21 | using namespace clang; |
| 22 | |
| 23 | namespace { |
Kovarththanan Rajaratnam | ba5fb5a | 2009-11-28 06:07:30 +0000 | [diff] [blame] | 24 | class PthreadLockChecker |
Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 25 | : public CheckerVisitor<PthreadLockChecker> { |
| 26 | BugType *BT; |
| 27 | public: |
| 28 | PthreadLockChecker() : BT(0) {} |
| 29 | static void *getTag() { |
| 30 | static int x = 0; |
| 31 | return &x; |
| 32 | } |
Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 33 | void PostVisitCallExpr(CheckerContext &C, const CallExpr *CE); |
| 34 | |
| 35 | void AcquireLock(CheckerContext &C, const CallExpr *CE, |
| 36 | SVal lock, bool isTryLock); |
| 37 | |
| 38 | void ReleaseLock(CheckerContext &C, const CallExpr *CE, |
| 39 | SVal lock); |
| 40 | |
| 41 | }; |
| 42 | } // end anonymous namespace |
| 43 | |
| 44 | // GDM Entry for tracking lock state. |
Kovarththanan Rajaratnam | ba5fb5a | 2009-11-28 06:07:30 +0000 | [diff] [blame] | 45 | namespace { class LockSet {}; } |
Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 46 | namespace clang { |
| 47 | template <> struct GRStateTrait<LockSet> : |
| 48 | public GRStatePartialTrait<llvm::ImmutableSet<const MemRegion*> > { |
| 49 | static void* GDMIndex() { return PthreadLockChecker::getTag(); } |
| 50 | }; |
| 51 | } // end clang namespace |
| 52 | |
| 53 | void clang::RegisterPthreadLockChecker(GRExprEngine &Eng) { |
| 54 | Eng.registerCheck(new PthreadLockChecker()); |
| 55 | } |
| 56 | |
Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 57 | |
| 58 | void PthreadLockChecker::PostVisitCallExpr(CheckerContext &C, |
| 59 | const CallExpr *CE) { |
| 60 | const GRState *state = C.getState(); |
| 61 | const Expr *Callee = CE->getCallee(); |
Ted Kremenek | eb1c7a0 | 2009-11-25 01:32:22 +0000 | [diff] [blame] | 62 | const FunctionTextRegion *R = |
| 63 | dyn_cast_or_null<FunctionTextRegion>(state->getSVal(Callee).getAsRegion()); |
Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 64 | |
| 65 | if (!R) |
| 66 | return; |
| 67 | |
| 68 | llvm::StringRef FName = R->getDecl()->getName(); |
| 69 | |
Ted Kremenek | fe37d04 | 2009-11-12 06:26:58 +0000 | [diff] [blame] | 70 | if (FName == "pthread_mutex_lock") { |
| 71 | if (CE->getNumArgs() != 1) |
| 72 | return; |
| 73 | AcquireLock(C, CE, state->getSVal(CE->getArg(0)), false); |
| 74 | } |
| 75 | else if (FName == "pthread_mutex_trylock") { |
| 76 | if (CE->getNumArgs() != 1) |
| 77 | return; |
| 78 | AcquireLock(C, CE, state->getSVal(CE->getArg(0)), true); |
| 79 | } |
| 80 | else if (FName == "pthread_mutex_unlock") { |
Ted Kremenek | ac9bea8 | 2009-11-12 06:17:47 +0000 | [diff] [blame] | 81 | if (CE->getNumArgs() != 1) |
| 82 | return; |
| 83 | ReleaseLock(C, CE, state->getSVal(CE->getArg(0))); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | void PthreadLockChecker::AcquireLock(CheckerContext &C, const CallExpr *CE, |
| 88 | SVal lock, bool isTryLock) { |
| 89 | |
| 90 | const MemRegion *lockR = lock.getAsRegion(); |
| 91 | if (!lockR) |
| 92 | return; |
| 93 | |
| 94 | const GRState *state = C.getState(); |
| 95 | |
| 96 | SVal X = state->getSVal(CE); |
| 97 | if (X.isUnknownOrUndef()) |
| 98 | return; |
| 99 | |
| 100 | DefinedSVal retVal = cast<DefinedSVal>(X); |
| 101 | const GRState *lockSucc = state; |
| 102 | |
| 103 | if (isTryLock) { |
| 104 | // Bifurcate the state, and allow a mode where the lock acquisition fails. |
| 105 | const GRState *lockFail; |
| 106 | llvm::tie(lockFail, lockSucc) = state->Assume(retVal); |
| 107 | assert(lockFail && lockSucc); |
| 108 | C.addTransition(C.GenerateNode(CE, lockFail)); |
| 109 | } |
| 110 | else { |
| 111 | // Assume that the return value was 0. |
| 112 | lockSucc = state->Assume(retVal, false); |
| 113 | assert(lockSucc); |
| 114 | } |
| 115 | |
| 116 | // Record that the lock was acquired. |
| 117 | lockSucc = lockSucc->add<LockSet>(lockR); |
| 118 | |
| 119 | C.addTransition(lockSucc != state ? C.GenerateNode(CE, lockSucc) : |
| 120 | C.getPredecessor()); |
| 121 | } |
| 122 | |
| 123 | void PthreadLockChecker::ReleaseLock(CheckerContext &C, const CallExpr *CE, |
| 124 | SVal lock) { |
| 125 | |
| 126 | const MemRegion *lockR = lock.getAsRegion(); |
| 127 | if (!lockR) |
| 128 | return; |
| 129 | |
| 130 | const GRState *state = C.getState(); |
| 131 | |
| 132 | // Record that the lock was released. |
| 133 | // FIXME: Handle unlocking locks that were never acquired. This may |
| 134 | // require IPA for wrappers. |
| 135 | const GRState *unlockState = state->remove<LockSet>(lockR); |
| 136 | |
| 137 | if (state == unlockState) |
| 138 | return; |
| 139 | |
| 140 | C.addTransition(C.GenerateNode(CE, unlockState)); |
| 141 | } |