Author: dcoughlin
Date: Tue Apr 12 19:41:54 2016
New Revision: 266157
URL: http://llvm.org/viewvc/llvm-project?rev=266157&view=rev
Log:
[analyzer] Nullability: Treat nil _Nonnull ivar as invariant violation.
Treat a _Nonnull ivar that is nil as an invariant violation in a similar
fashion to how a nil _Nonnull parameter is treated as a precondition violation.
This avoids warning on defensive returns of nil on defensive internal
checks, such as the following common idiom:
@class InternalImplementation
@interface PublicClass {
InternalImplementation * _Nonnull _internal;
}
-(id _Nonnull)foo;
@end
@implementation PublicClass
-(id _Nonnull)foo {
if (!_internal)
return nil; // no-warning
return [_internal foo];
}
@end
rdar://problem/24485171
Modified:
cfe/trunk/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp
cfe/trunk/test/Analysis/nullability.mm
Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp?rev=266157&r1=266156&r2=266157&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp Tue Apr 12
19:41:54 2016
@@ -356,29 +356,70 @@ static Nullability getNullabilityAnnotat
return Nullability::Unspecified;
}
-template <typename ParamVarDeclRange>
+/// Returns true when the value stored at the given location is null
+/// and the passed in type is nonnnull.
+static bool checkValueAtLValForInvariantViolation(ProgramStateRef State,
+ SVal LV, QualType T) {
+ if (getNullabilityAnnotation(T) != Nullability::Nonnull)
+ return false;
+
+ auto RegionVal = LV.getAs<loc::MemRegionVal>();
+ if (!RegionVal)
+ return false;
+
+ auto StoredVal =
+ State->getSVal(RegionVal->getRegion()).getAs<DefinedOrUnknownSVal>();
+ if (!StoredVal)
+ return false;
+
+ if (getNullConstraint(*StoredVal, State) == NullConstraint::IsNull)
+ return true;
+
+ return false;
+}
+
static bool
-checkParamsForPreconditionViolation(const ParamVarDeclRange &Params,
+checkParamsForPreconditionViolation(ArrayRef<ParmVarDecl *> Params,
ProgramStateRef State,
const LocationContext *LocCtxt) {
for (const auto *ParamDecl : Params) {
if (ParamDecl->isParameterPack())
break;
- if (getNullabilityAnnotation(ParamDecl->getType()) != Nullability::Nonnull)
- continue;
+ SVal LV = State->getLValue(ParamDecl, LocCtxt);
+ if (checkValueAtLValForInvariantViolation(State, LV,
+ ParamDecl->getType())) {
+ return true;
+ }
+ }
+ return false;
+}
+
+static bool
+checkSelfIvarsForInvariantViolation(ProgramStateRef State,
+ const LocationContext *LocCtxt) {
+ auto *MD = dyn_cast<ObjCMethodDecl>(LocCtxt->getDecl());
+ if (!MD || !MD->isInstanceMethod())
+ return false;
- auto RegVal = State->getLValue(ParamDecl, LocCtxt)
- .template getAs<loc::MemRegionVal>();
- if (!RegVal)
- continue;
-
- auto ParamValue = State->getSVal(RegVal->getRegion())
- .template getAs<DefinedOrUnknownSVal>();
- if (!ParamValue)
- continue;
+ const ImplicitParamDecl *SelfDecl = LocCtxt->getSelfDecl();
+ if (!SelfDecl)
+ return false;
+
+ SVal SelfVal = State->getSVal(State->getRegion(SelfDecl, LocCtxt));
+
+ const ObjCObjectPointerType *SelfType =
+ dyn_cast<ObjCObjectPointerType>(SelfDecl->getType());
+ if (!SelfType)
+ return false;
+
+ const ObjCInterfaceDecl *ID = SelfType->getInterfaceDecl();
+ if (!ID)
+ return false;
- if (getNullConstraint(*ParamValue, State) == NullConstraint::IsNull) {
+ for (const auto *IvarDecl : ID->ivars()) {
+ SVal LV = State->getLValue(IvarDecl, SelfVal);
+ if (checkValueAtLValForInvariantViolation(State, LV, IvarDecl->getType()))
{
return true;
}
}
@@ -405,7 +446,8 @@ static bool checkInvariantViolation(Prog
else
return false;
- if (checkParamsForPreconditionViolation(Params, State, LocCtxt)) {
+ if (checkParamsForPreconditionViolation(Params, State, LocCtxt) ||
+ checkSelfIvarsForInvariantViolation(State, LocCtxt)) {
if (!N->isSink())
C.addTransition(State->set<InvariantViolated>(true), N);
return true;
Modified: cfe/trunk/test/Analysis/nullability.mm
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/nullability.mm?rev=266157&r1=266156&r2=266157&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/nullability.mm (original)
+++ cfe/trunk/test/Analysis/nullability.mm Tue Apr 12 19:41:54 2016
@@ -444,3 +444,45 @@ void callMethodInSystemHeader() {
// expected-warning@-2{{Nullable pointer is passed to a callee that requires
a non-null 1st parameter}}
#endif
}
+
+// Test to make sure the analyzer doesn't warn when an a nullability invariant
+// has already been found to be violated on an instance variable.
+
+@class MyInternalClass;
+@interface MyClass : NSObject {
+ MyInternalClass * _Nonnull _internal;
+}
+@end
+
+@interface MyInternalClass : NSObject {
+ @public
+ id _someIvar;
+}
+-(id _Nonnull)methodWithInternalImplementation;
+@end
+
+@interface MyClass () {
+ MyInternalClass * _Nonnull _nilledOutInternal;
+}
+@end
+
+@implementation MyClass
+-(id _Nonnull)methodWithInternalImplementation {
+ if (!_internal)
+ return nil; // no-warning
+
+ return [_internal methodWithInternalImplementation];
+}
+
+- (id _Nonnull)methodReturningIvarInImplementation; {
+ return _internal == 0 ? nil : _internal->_someIvar; // no-warning
+}
+
+-(id _Nonnull)methodWithNilledOutInternal {
+ // The cast below should (but does not yet) suppress the warning on the
+ // assignment.
+ _nilledOutInternal = (id _Nonnull)nil; // expected-warning {{Null is
assigned to a pointer which is expected to have non-null value}}
+
+ return nil; // no-warning
+}
+@end
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