[analyzer] Enhance the member expr tracking to account for references.

As per Jordan's suggestion. (Came out of code review for r163261.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163269 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 9 insertions, 2 deletions

diff --git a/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp b/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
index 45f40368ea..45d854b008 100644
--- a/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
@@ -130,7 +130,7 @@ void DereferenceChecker::reportBug(ProgramStateRef State, const Stmt *S,
   }
   case Stmt::MemberExprClass: {
     const MemberExpr *M = cast<MemberExpr>(S);
-    if (M->isArrow()) {
+    if (M->isArrow() || bugreporter::isDeclRefExprToReference(M->getBase())) {
       llvm::raw_svector_ostream os(buf);
       os << "Access to field '" << M->getMemberNameInfo()
          << "' results in a dereference of a null pointer";
diff --git a/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp b/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
index be90de1f34..d5fe1e0a45 100644
--- a/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -31,6 +31,13 @@ using namespace ento;
 // Utility functions.
 //===----------------------------------------------------------------------===//
 
+bool bugreporter::isDeclRefExprToReference(const Expr *E) {
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
+    return DRE->getDecl()->getType()->isReferenceType();
+  }
+  return false;
+}
+
 const Stmt *bugreporter::GetDerefExpr(const ExplodedNode *N) {
   // Pattern match for a few useful cases (do something smarter later):
   //   a[0], p->f, *p
@@ -54,7 +61,7 @@ const Stmt *bugreporter::GetDerefExpr(const ExplodedNode *N) {
         return U->getSubExpr()->IgnoreParenCasts();
     }
     else if (const MemberExpr *ME = dyn_cast<MemberExpr>(S)) {
-      if (ME->isArrow()) {
+      if (ME->isArrow() || isDeclRefExprToReference(ME->getBase())) {
         return ME->getBase()->IgnoreParenCasts();
       }
     }