[analyzer] Add a simple check for initializing reference variables with null.

There's still more work to be done here; this doesn't catch reference
parameters or return values. But it's a step in the right direction.

Part of <rdar://problem/11212286>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161214 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 0 deletions

diff --git a/test/Analysis/reference.cpp b/test/Analysis/reference.cpp
index a12e0bd41c..c9bfadced7 100644
--- a/test/Analysis/reference.cpp
+++ b/test/Analysis/reference.cpp
@@ -90,3 +90,29 @@ namespace PR13440 {
     clang_analyzer_eval(s2.x[0] == 42); // expected-warning{{TRUE}}
   }
 }
+
+void testRef() {
+  int *x = 0;
+  int &y = *x; // expected-warning{{Dereference of null pointer}}
+  y = 5;
+}
+
+
+// ------------------------------------
+// False negatives
+// ------------------------------------
+
+namespace rdar11212286 {
+  class B{};
+
+  B test() {
+    B *x = 0;
+    return *x; // should warn here!
+  }
+
+  B &testRef() {
+    B *x = 0;
+    return *x; // should warn here!
+  }
+
+}