[analyzer] Ensure that the node NilReceiverBRVisitor is looking for is not reclaimed

The visitor should look for the PreStmt node as the receiver is nil in the PreStmt and this is the node. Also, tag the nil
receiver nodes with a special tag for consistency.

llvm-svn: 178152

1 files changed, 4 insertions, 3 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
index 37e203df8e8..75c7df8734f 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
@@ -397,6 +397,7 @@ void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C,
                                               ProgramStateRef state,
                                               const ObjCMethodCall &Msg) const {
   ASTContext &Ctx = C.getASTContext();
+  static SimpleProgramPointTag Tag("CallAndMessageChecker : NilReceiver");
 
   // Check the return type of the message expression.  A message to nil will
   // return different values depending on the return type and the architecture.
@@ -407,7 +408,7 @@ void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C,
   if (CanRetTy->isStructureOrClassType()) {
     // Structure returns are safe since the compiler zeroes them out.
     SVal V = C.getSValBuilder().makeZeroVal(RetTy);
-    C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V));
+    C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V), &Tag);
     return;
   }
 
@@ -425,7 +426,7 @@ void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C,
            Ctx.LongDoubleTy == CanRetTy ||
            Ctx.LongLongTy == CanRetTy ||
            Ctx.UnsignedLongLongTy == CanRetTy))) {
-      if (ExplodedNode *N = C.generateSink(state))
+      if (ExplodedNode *N = C.generateSink(state, 0 , &Tag))
         emitNilReceiverBug(C, Msg, N);
       return;
     }
@@ -444,7 +445,7 @@ void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C,
     // of this case unless we have *a lot* more knowledge.
     //
     SVal V = C.getSValBuilder().makeZeroVal(RetTy);
-    C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V));
+    C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V), &Tag);
     return;
   }