Functions can be lvalues in C++, but not modifiable lvalues

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57941 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index d957e33..4fd8a24 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -422,7 +422,13 @@
   isLvalueResult lvalResult = isLvalue(Ctx);
     
   switch (lvalResult) {
-  case LV_Valid: break;
+  case LV_Valid: 
+    // C++ 3.10p11: Functions cannot be modified, but pointers to
+    // functions can be modifiable.
+    if (Ctx.getLangOptions().CPlusPlus && TR->isFunctionType())
+      return MLV_NotObjectType;
+    break;
+
   case LV_NotObjectType: return MLV_NotObjectType;
   case LV_IncompleteVoidType: return MLV_IncompleteVoidType;
   case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;