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[analyzer] PthreadLock: Fix return value modeling for XNU lock functions. 

Differential Revision: https://reviews.llvm.org/D37806
This commit is contained in:
Artem Dergachev 2020-01-24 17:52:41 +03:00
parent 3fd5d1c6e7
commit 80fd37f9d6
2 changed files with 31 additions and 25 deletions
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48
clang/lib/StaticAnalyzer/Checkers/PthreadLockChecker.cpp
View File

@ -226,12 +226,6 @@ void PthreadLockChecker::AcquireLock(CheckerContext &C, const CallExpr *CE,
if (sym)
state = resolvePossiblyDestroyedMutex(state, lockR, sym);
SVal X = C.getSVal(CE);
if (X.isUnknownOrUndef())
return;
DefinedSVal retVal = X.castAs<DefinedSVal>();
if (const LockState *LState = state->get<LockMap>(lockR)) {
if (LState->isLocked()) {
if (!BT_doublelock)
@ -254,25 +248,35 @@ void PthreadLockChecker::AcquireLock(CheckerContext &C, const CallExpr *CE,
ProgramStateRef lockSucc = state;
if (isTryLock) {
// Bifurcate the state, and allow a mode where the lock acquisition fails.
ProgramStateRef lockFail;
switch (semantics) {
case PthreadSemantics:
std::tie(lockFail, lockSucc) = state->assume(retVal);
break;
case XNUSemantics:
std::tie(lockSucc, lockFail) = state->assume(retVal);
break;
default:
llvm_unreachable("Unknown tryLock locking semantics");
SVal RetVal = state->getSVal(CE, C.getLocationContext());
if (auto DefinedRetVal = RetVal.getAs<DefinedSVal>()) {
ProgramStateRef lockFail;
switch (semantics) {
case PthreadSemantics:
std::tie(lockFail, lockSucc) = state->assume(*DefinedRetVal);
break;
case XNUSemantics:
std::tie(lockSucc, lockFail) = state->assume(*DefinedRetVal);
break;
default:
llvm_unreachable("Unknown tryLock locking semantics");
}
assert(lockFail && lockSucc);
C.addTransition(lockFail);
}
assert(lockFail && lockSucc);
C.addTransition(lockFail);
// We might want to handle the case when the mutex lock function was inlined
// and returned an Unknown or Undefined value.
} else if (semantics == PthreadSemantics) {
// Assume that the return value was 0.
lockSucc = state->assume(retVal, false);
assert(lockSucc);
SVal RetVal = state->getSVal(CE, C.getLocationContext());
if (auto DefinedRetVal = RetVal.getAs<DefinedSVal>()) {
// FIXME: If the lock function was inlined and returned true,
// we need to behave sanely - at least generate sink.
lockSucc = state->assume(*DefinedRetVal, false);
assert(lockSucc);
}
// We might want to handle the case when the mutex lock function was inlined
// and returned an Unknown or Undefined value.
} else {
// XNU locking semantics return void on non-try locks
assert((semantics == XNUSemantics) && "Unknown locking semantics");

8
clang/test/Analysis/Inputs/system-header-simulator-for-pthread-lock.h
View File

@ -22,7 +22,9 @@ extern int pthread_mutex_unlock(pthread_mutex_t *);
extern int pthread_mutex_trylock(pthread_mutex_t *);
extern int pthread_mutex_destroy(pthread_mutex_t *);
extern int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *mutexattr);
extern int lck_mtx_lock(lck_mtx_t *);
extern int lck_mtx_unlock(lck_mtx_t *);
extern int lck_mtx_try_lock(lck_mtx_t *);
typedef int boolean_t;
extern void lck_mtx_lock(lck_mtx_t *);
extern void lck_mtx_unlock(lck_mtx_t *);
extern boolean_t lck_mtx_try_lock(lck_mtx_t *);
extern void lck_mtx_destroy(lck_mtx_t *lck, lck_grp_t *grp);