[analyzer] teach ExprEngine about loads from static C++ class fields. Fixes <rdar://problem/9948787>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137760 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 35 insertions, 1 deletions

diff --git a/lib/StaticAnalyzer/Core/ExprEngine.cpp b/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 1ea90047fa..916734b4e7 100644
--- a/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -1380,7 +1380,14 @@ void ExprEngine::VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *A,
 void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
                                  ExplodedNodeSet &Dst) {
 
-  FieldDecl *field = dyn_cast<FieldDecl>(M->getMemberDecl());
+  Decl *member = M->getMemberDecl();
+  if (VarDecl *VD = dyn_cast<VarDecl>(member)) {
+    assert(M->isLValue());
+    VisitCommonDeclRefExpr(M, VD, Pred, Dst);
+    return;
+  }
+  
+  FieldDecl *field = dyn_cast<FieldDecl>(member);
   if (!field) // FIXME: skipping member expressions for non-fields
     return;
 
diff --git a/test/Analysis/misc-ps-region-store.cpp b/test/Analysis/misc-ps-region-store.cpp
index f27b910e1a..1d055d5968 100644
--- a/test/Analysis/misc-ps-region-store.cpp
+++ b/test/Analysis/misc-ps-region-store.cpp
@@ -414,3 +414,30 @@ void TestAssignIntoSymbolicOffset::test(int x, int y) {
   }
 }
 
+// Test loads from static fields.  This previously triggered an uninitialized
+// value warning.
+class ClassWithStatic {
+public:
+    static const unsigned value = 1;
+};
+
+int rdar9948787_negative() {
+    ClassWithStatic classWithStatic;
+    unsigned value = classWithStatic.value;
+    if (value == 1)
+      return 1;
+    int *p = 0;
+    *p = 0xDEADBEEF; // no-warning
+    return 0;
+}
+
+int rdar9948787_positive() {
+    ClassWithStatic classWithStatic;
+    unsigned value = classWithStatic.value;
+    if (value == 0)
+      return 1;
+    int *p = 0;
+    *p = 0xDEADBEEF; // expected-warning {{null}}
+    return 0;
+}
+