Give a diagnostic when using non-POD types in a va_arg

llvm-svn: 132905

Author: majnemer

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -3933,6 +3933,9 @@ def warn_second_parameter_of_va_start_not_last_named_argument : Warning<
   "second parameter of 'va_start' not last named argument">;
 def err_first_argument_to_va_arg_not_of_type_va_list : Error<
   "first argument to 'va_arg' is of type %0 and not 'va_list'">;
+def warn_second_parameter_to_va_arg_not_pod : Warning<
+  "second argument to 'va_arg' is of non-POD type %0">,
+  InGroup<DiagGroup<"non-pod-varargs">>, DefaultError;
 
 def warn_return_missing_expr : Warning<
   "non-void %select{function|method}1 %0 should return a value">, DefaultError,

clang/lib/Sema/SemaExpr.cpp

@@ -9819,7 +9819,11 @@ ExprResult Sema::BuildVAArgExpr(SourceLocation BuiltinLoc,
   }
 
   // FIXME: Check that type is complete/non-abstract
-  // FIXME: Warn if a non-POD type is passed in.
+
+  if (!TInfo->getType()->isDependentType() && !TInfo->getType()->isPODType())
+    return ExprError(Diag(TInfo->getTypeLoc().getBeginLoc(),
+                         diag::warn_second_parameter_to_va_arg_not_pod)
+      << TInfo->getType() << TInfo->getTypeLoc().getSourceRange());
 
   QualType T = TInfo->getType().getNonLValueExprType(Context);
   return Owned(new (Context) VAArgExpr(BuiltinLoc, E, TInfo, RPLoc, T));

clang/test/SemaTemplate/instantiate-expr-3.cpp

@@ -117,3 +117,12 @@ struct VaArg1 {
 
 template struct VaArg1<__builtin_va_list, int>;
 template struct VaArg1<int, int>; // expected-note{{instantiation}}
+
+struct VaArg2 {
+  virtual void f(int n, ...) {
+    __builtin_va_list va;
+    __builtin_va_start(va, n);
+    (void)__builtin_va_arg(va, VaArg2); // expected-error {{second argument to 'va_arg' is of non-POD type 'VaArg2'}}
+    __builtin_va_end(va);
+  }
+};