diff --git a/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp b/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp
--- a/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp
+++ b/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp
@@ -120,7 +120,9 @@
   initializeOutputStream(nullptr, nullptr, OS, 1024);
   this->output(OS, Flags);
   OS << '\0';
-  return {OS.getBuffer()};
+  std::string Owned(OS.getBuffer());
+  std::free(OS.getBuffer());
+  return Owned;
 }
 
 void PrimitiveTypeNode::outputPre(OutputStream &OS, OutputFlags Flags) const {