1 files changed, 15 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 51ba96fb1e8..9e3647548be 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -5685,6 +5685,21 @@ void Sema::checkClassLevelDLLAttribute(CXXRecordDecl *Class) {
           cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
       NewAttr->setInherited(true);
       Member->addAttr(NewAttr);
+
+      if (MD) {
+        // Propagate DLLAttr to friend re-declarations of MD that have already
+        // been constructed.
+        for (FunctionDecl *FD = MD->getMostRecentDecl(); FD;
+             FD = FD->getPreviousDecl()) {
+          if (FD->getFriendObjectKind() == Decl::FOK_None)
+            continue;
+          assert(!getDLLAttr(FD) &&
+                 "friend re-decl should not already have a DLLAttr");
+          NewAttr = cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
+          NewAttr->setInherited(true);
+          FD->addAttr(NewAttr);
+        }
+      }
     }
   }