Enhance analyzer reasoning about sending messages to nil. A nil receiver returns 0 for scalars of size <= sizeof(void*).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68629 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/GRExprEngine.cpp b/lib/Analysis/GRExprEngine.cpp
index 06d61cc..b2dfe68 100644
--- a/lib/Analysis/GRExprEngine.cpp
+++ b/lib/Analysis/GRExprEngine.cpp
@@ -1682,7 +1682,7 @@
// "Assume" that the receiver is not NULL.
bool isFeasibleNotNull = false;
- Assume(state, L, true, isFeasibleNotNull);
+ const GRState *StNotNull = Assume(state, L, true, isFeasibleNotNull);
// "Assume" that the receiver is NULL.
bool isFeasibleNull = false;
@@ -1724,8 +1724,21 @@
NilReceiverLargerThanVoidPtrRetExplicit.insert(N);
}
}
+ else {
+ // Handle the safe cases where the return value is 0 if the receiver
+ // is nil.
+ SVal V = SVal::MakeZero(getBasicVals(), ME->getType());
+ MakeNode(Dst, ME, Pred, BindExpr(StNull, ME, V));
+ }
}
}
+
+ // We have handled the cases where the receiver is nil. The remainder
+ // of this method should assume that the receiver is not nil.
+ if (!isFeasibleNotNull)
+ return;
+
+ state = StNotNull;
}
// Check if the "raise" message was sent.
@@ -2445,7 +2458,7 @@
// transfer functions as "0 == E".
if (isa<Loc>(V)) {
- loc::ConcreteInt X(getBasicVals().getZeroWithPtrWidth());
+ Loc X = Loc::MakeNull(getBasicVals());
SVal Result = EvalBinOp(BinaryOperator::EQ, cast<Loc>(V), X,
U->getType());
state = BindExpr(state, U, Result);
diff --git a/lib/Analysis/SVals.cpp b/lib/Analysis/SVals.cpp
index b642857..c5900b3 100644
--- a/lib/Analysis/SVals.cpp
+++ b/lib/Analysis/SVals.cpp
@@ -202,6 +202,22 @@
}
//===----------------------------------------------------------------------===//
+// Utility methods for constructing SVals.
+//===----------------------------------------------------------------------===//
+
+SVal SVal::MakeZero(BasicValueFactory &BasicVals, QualType T) {
+ if (Loc::IsLocType(T))
+ return Loc::MakeNull(BasicVals);
+
+ if (T->isIntegerType())
+ return NonLoc::MakeVal(BasicVals, 0, T);
+
+ // FIXME: Handle floats.
+ // FIXME: Handle structs.
+ return UnknownVal();
+}
+
+//===----------------------------------------------------------------------===//
// Utility methods for constructing Non-Locs.
//===----------------------------------------------------------------------===//
@@ -314,6 +330,10 @@
Loc Loc::MakeVal(SymbolRef sym) { return loc::SymbolVal(sym); }
+Loc Loc::MakeNull(BasicValueFactory &BasicVals) {
+ return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
+}
+
//===----------------------------------------------------------------------===//
// Pretty-Printing.
//===----------------------------------------------------------------------===//