diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 738f117ad0b..63a3214c174 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -41,6 +41,7 @@ class DIEAbbrev;
 class DIE;
 class DIEBlock;
 class DIEEntry;
+class DwarfDebug;
 
 //===----------------------------------------------------------------------===//
 /// \brief This class is used to record source line correspondence.