In VirtualCallChecker, handle indirect calls

Summary:
In VirtualCallChecker, handle indirect calls.

getDirectCallee() can be nullptr, and dyn_cast(nullptr) is UB

Reviewers: bkramer

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D29303

llvm-svn: 293604

clang/lib/StaticAnalyzer/Checkers/VirtualCallChecker.cpp

@@ -179,7 +179,8 @@ void WalkAST::VisitCXXMemberCallExpr(CallExpr *CE) {
   }
 
   // Get the callee.
-  const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CE->getDirectCallee());
+  const CXXMethodDecl *MD =
+      dyn_cast_or_null<CXXMethodDecl>(CE->getDirectCallee());
   if (MD && MD->isVirtual() && !callIsNonVirtual && !MD->hasAttr<FinalAttr>() &&
       !MD->getParent()->hasAttr<FinalAttr>())
     ReportVirtualCall(CE, MD->isPure());

clang/test/Analysis/virtualcall.cpp

@@ -115,12 +115,23 @@ class E final : public B {
   int foo() override;
 };
 
+// Regression test: don't crash when there's no direct callee.
+class F {
+public:
+  F() {
+    void (F::* ptr)() = &F::foo;
+    (this->*ptr)();
+  }
+  void foo();
+};
+
 int main() {
   A *a;
   B *b;
   C *c;
   D *d;
   E *e;
+  F *f;
 }
 
 #include "virtualcall.h"