diff --git a/lldb/include/lldb/Utility/StringList.h b/lldb/include/lldb/Utility/StringList.h
--- a/lldb/include/lldb/Utility/StringList.h
+++ b/lldb/include/lldb/Utility/StringList.h
@@ -10,6 +10,7 @@
 #define LLDB_UTILITY_STRINGLIST_H
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
 
 #include <cstddef>
 #include <string>
@@ -44,6 +45,8 @@
 
   void AppendString(llvm::StringRef str);
 
+  void AppendString(const llvm::Twine &str);
+
   void AppendList(const char **strv, int strc);
 
   void AppendList(StringList strings);
diff --git a/lldb/source/Utility/StringList.cpp b/lldb/source/Utility/StringList.cpp
--- a/lldb/source/Utility/StringList.cpp
+++ b/lldb/source/Utility/StringList.cpp
@@ -55,6 +55,10 @@
   m_strings.push_back(str.str());
 }
 
+void StringList::AppendString(const llvm::Twine &str) {
+  m_strings.push_back(str.str());
+}
+
 void StringList::AppendList(const char **strv, int strc) {
   for (int i = 0; i < strc; ++i) {
     if (strv[i])