diff --git a/llvm/include/llvm/Support/LineIterator.h b/llvm/include/llvm/Support/LineIterator.h
index fc6871baf99a6..fe484c1940816 100644
--- a/llvm/include/llvm/Support/LineIterator.h
+++ b/llvm/include/llvm/Support/LineIterator.h
@@ -10,6 +10,7 @@
 #define LLVM_SUPPORT_LINEITERATOR_H
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/MemoryBufferRef.h"
 #include <iterator>
@@ -30,7 +31,7 @@ class MemoryBuffer;
 /// character.
 ///
 /// Note that this iterator requires the buffer to be nul terminated.
-class line_iterator {
+class LLVM_ABI line_iterator {
   std::optional<MemoryBufferRef> Buffer;
   char CommentMarker = '\0';
   bool SkipBlanks = true;