/// \brief Run checkers for evaluating a call.
/// Only one checker will evaluate the call.
void CheckerManager::runCheckersForEvalCall(ExplodedNodeSet &Dst,
const ExplodedNodeSet &Src,
const CallEvent &Call,
ExprEngine &Eng) {
const CallExpr *CE = cast<CallExpr>(Call.getOriginExpr());
for (ExplodedNodeSet::iterator
NI = Src.begin(), NE = Src.end(); NI != NE; ++NI) {
ExplodedNode *Pred = *NI;
bool anyEvaluated = false;
ExplodedNodeSet checkDst;
NodeBuilder B(Pred, checkDst, Eng.getBuilderContext());
// Check if any of the EvalCall callbacks can evaluate the call.
for (std::vector<EvalCallFunc>::iterator
EI = EvalCallCheckers.begin(), EE = EvalCallCheckers.end();
EI != EE; ++EI) {
ProgramPoint::Kind K = ProgramPoint::PostStmtKind;
const ProgramPoint &L = ProgramPoint::getProgramPoint(CE, K,
Pred->getLocationContext(), EI->Checker);
bool evaluated = false;
{ // CheckerContext generates transitions(populates checkDest) on
// destruction, so introduce the scope to make sure it gets properly
// populated.
CheckerContext C(B, Eng, Pred, L);
evaluated = (*EI)(CE, C);
}
assert(!(evaluated && anyEvaluated)
&& "There are more than one checkers evaluating the call");
if (evaluated) {
anyEvaluated = true;
Dst.insert(checkDst);
#ifdef NDEBUG
break; // on release don't check that no other checker also evals.
#endif
}
}
// If none of the checkers evaluated the call, ask ExprEngine to handle it.
if (!anyEvaluated) {
NodeBuilder B(Pred, Dst, Eng.getBuilderContext());
Eng.defaultEvalCall(B, Pred, Call);
}
}
}
bool OSAtomicChecker::evalOSAtomicCompareAndSwap(const CallExpr *CE,
ExprEngine &Eng,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) const {
// Not enough arguments to match OSAtomicCompareAndSwap?
if (CE->getNumArgs() != 3)
return false;
ASTContext &Ctx = Eng.getContext();
const Expr *oldValueExpr = CE->getArg(0);
QualType oldValueType = Ctx.getCanonicalType(oldValueExpr->getType());
const Expr *newValueExpr = CE->getArg(1);
QualType newValueType = Ctx.getCanonicalType(newValueExpr->getType());
// Do the types of 'oldValue' and 'newValue' match?
if (oldValueType != newValueType)
return false;
const Expr *theValueExpr = CE->getArg(2);
const PointerType *theValueType=theValueExpr->getType()->getAs<PointerType>();
// theValueType not a pointer?
if (!theValueType)
return false;
QualType theValueTypePointee =
Ctx.getCanonicalType(theValueType->getPointeeType()).getUnqualifiedType();
// The pointee must match newValueType and oldValueType.
if (theValueTypePointee != newValueType)
return false;
static SimpleProgramPointTag OSAtomicLoadTag("OSAtomicChecker : Load");
static SimpleProgramPointTag OSAtomicStoreTag("OSAtomicChecker : Store");
// Load 'theValue'.
ProgramStateRef state = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
ExplodedNodeSet Tmp;
SVal location = state->getSVal(theValueExpr, LCtx);
// Here we should use the value type of the region as the load type, because
// we are simulating the semantics of the function, not the semantics of
// passing argument. So the type of theValue expr is not we are loading.
// But usually the type of the varregion is not the type we want either,
// we still need to do a CastRetrievedVal in store manager. So actually this
// LoadTy specifying can be omitted. But we put it here to emphasize the
// semantics.
QualType LoadTy;
if (const TypedValueRegion *TR =
dyn_cast_or_null<TypedValueRegion>(location.getAsRegion())) {
LoadTy = TR->getValueType();
}
Eng.evalLoad(Tmp, CE, theValueExpr, Pred,
state, location, &OSAtomicLoadTag, LoadTy);
if (Tmp.empty()) {
// If no nodes were generated, other checkers must have generated sinks.
// We return an empty Dst.
return true;
}
for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end();
I != E; ++I) {
ExplodedNode *N = *I;
ProgramStateRef stateLoad = N->getState();
// Use direct bindings from the environment since we are forcing a load
// from a location that the Environment would typically not be used
// to bind a value.
SVal theValueVal_untested = stateLoad->getSVal(theValueExpr, LCtx, true);
SVal oldValueVal_untested = stateLoad->getSVal(oldValueExpr, LCtx);
// FIXME: Issue an error.
if (theValueVal_untested.isUndef() || oldValueVal_untested.isUndef()) {
return false;
}
DefinedOrUnknownSVal theValueVal =
cast<DefinedOrUnknownSVal>(theValueVal_untested);
DefinedOrUnknownSVal oldValueVal =
cast<DefinedOrUnknownSVal>(oldValueVal_untested);
SValBuilder &svalBuilder = Eng.getSValBuilder();
// Perform the comparison.
DefinedOrUnknownSVal Cmp =
svalBuilder.evalEQ(stateLoad,theValueVal,oldValueVal);
ProgramStateRef stateEqual = stateLoad->assume(Cmp, true);
// Were they equal?
if (stateEqual) {
// Perform the store.
ExplodedNodeSet TmpStore;
SVal val = stateEqual->getSVal(newValueExpr, LCtx);
// Handle implicit value casts.
if (const TypedValueRegion *R =
dyn_cast_or_null<TypedValueRegion>(location.getAsRegion())) {
val = svalBuilder.evalCast(val,R->getValueType(), newValueExpr->getType());
}
Eng.evalStore(TmpStore, CE, theValueExpr, N,
stateEqual, location, val, &OSAtomicStoreTag);
if (TmpStore.empty()) {
// If no nodes were generated, other checkers must have generated sinks.
// We return an empty Dst.
return true;
}
StmtNodeBuilder B(TmpStore, Dst, Eng.getBuilderContext());
// Now bind the result of the comparison.
for (ExplodedNodeSet::iterator I2 = TmpStore.begin(),
E2 = TmpStore.end(); I2 != E2; ++I2) {
ExplodedNode *predNew = *I2;
ProgramStateRef stateNew = predNew->getState();
// Check for 'void' return type if we have a bogus function prototype.
SVal Res = UnknownVal();
QualType T = CE->getType();
if (!T->isVoidType())
Res = Eng.getSValBuilder().makeTruthVal(true, T);
B.generateNode(CE, predNew, stateNew->BindExpr(CE, LCtx, Res), this);
}
}
// Were they not equal?
if (ProgramStateRef stateNotEqual = stateLoad->assume(Cmp, false)) {
// Check for 'void' return type if we have a bogus function prototype.
SVal Res = UnknownVal();
QualType T = CE->getType();
if (!T->isVoidType())
Res = Eng.getSValBuilder().makeTruthVal(false, CE->getType());
StmtNodeBuilder B(N, Dst, Eng.getBuilderContext());
B.generateNode(CE, N, stateNotEqual->BindExpr(CE, LCtx, Res), this);
}
}
return true;
}
