-Wuninitialized: warn about uninitialized values resulting from ?: that evaluate to lvalues (in C++).

llvm-svn: 172875

clang/lib/Analysis/UninitializedValues.cpp

@@ -358,6 +358,16 @@ static const DeclRefExpr *getSelfInitExpr(VarDecl *VD) {
 }
 
 void ClassifyRefs::classify(const Expr *E, Class C) {
+  // The result of a ?: could also be an lvalue.
+  E = E->IgnoreParens();
+  if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
+    const Expr *TrueExpr = CO->getTrueExpr();
+    if (!isa<OpaqueValueExpr>(TrueExpr))
+      classify(TrueExpr, C);
+    classify(CO->getFalseExpr(), C);
+    return;
+  }
+
   FindVarResult Var = findVar(E, DC);
   if (const DeclRefExpr *DRE = Var.getDeclRefExpr())
     Classification[DRE] = std::max(Classification[DRE], C);

clang/test/SemaCXX/uninitialized.cpp

@@ -41,8 +41,8 @@ void test_stuff () {
   int j = far(j);
   int k = __alignof__(k);
 
-  int l = k ? l : l;  // FIXME: warn here
-  int m = 1 + (k ? m : m);  // FIXME: warn here
+  int l = k ? l : l;  // expected-warning {{variable 'l' is uninitialized when used within its own initialization}}
+  int m = 1 + (k ? m : m);  // expected-warning {{'m' is uninitialized when used within its own initialization}}
   int n = -n;  // expected-warning {{variable 'n' is uninitialized when used within its own initialization}}
 
   for (;;) {
@@ -61,8 +61,8 @@ void test_stuff () {
     int j = far(j);
     int k = __alignof__(k);
 
-    int l = k ? l : l;  // FIXME: warn here
-    int m = 1 + (k ? m : m);  // FIXME: warn here
+    int l = k ? l : l;  // expected-warning {{variable 'l' is uninitialized when used within its own initialization}}
+    int m = 1 + (k ? m : m);  // expected-warning {{'m' is uninitialized when used within its own initialization}}
     int n = -n;  // expected-warning {{variable 'n' is uninitialized when used within its own initialization}}
   }
 }