[analyzer] Fix a crash in RetainCountChecker - we should not rely on CallEnter::getCallExpr to return non-NULL

We get a CallEnter with a null expression, when processing a destructor. All other users of
CallEnter::getCallExpr work fine with null as return value.

(Addresses PR15832, Thanks to Jordan for reducing the test case!)

llvm-svn: 180234

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
index 824ce34ab33..0d256006e1c 100644
--- a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
@@ -2192,7 +2192,7 @@ GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N,
     if (!InitMethodContext)
       if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) {
         const Stmt *CE = CEP->getCallExpr();
-        if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(CE)) {
+        if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) {
           const Stmt *RecExpr = ME->getInstanceReceiver();
           if (RecExpr) {
             SVal RecV = St->getSVal(RecExpr, NContext);