Add check for UnknownVals for mutexes in ObjCAtSyncChecker. Fixes crash reported in PR 8458.

llvm-svn: 117300

clang/lib/Checker/ObjCAtSyncChecker.cpp

@@ -57,6 +57,9 @@ void ObjCAtSyncChecker::PreVisitObjCAtSynchronizedStmt(CheckerContext &C,
     return;
   }
 
+  if (V.isUnknown())
+    return;
+
   // Check for null mutexes.
   const GRState *notNullState, *nullState;
   llvm::tie(notNullState, nullState) = state->Assume(cast<DefinedSVal>(V));

clang/test/Analysis/misc-ps.m

@@ -1149,3 +1149,13 @@ void pr8149(void) {
   for (; ({ do { } while (0); 0; });) { }
 }
 
+// PR 8458 - Make sure @synchronized doesn't crash with properties.
+@interface PR8458 {}
+@property(readonly) id lock;
+@end
+
+static
+void __PR8458(PR8458 *x) {
+  @synchronized(x.lock) {} // no-warning
+}
+