diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp
index 8f9058b..321af98 100644
--- a/lib/Target/TargetLoweringObjectFile.cpp
+++ b/lib/Target/TargetLoweringObjectFile.cpp
@@ -511,7 +511,7 @@
 
 
 const MCSection *TargetLoweringObjectFileMachO::
-getMachOSection(StringRef Segment, StringRef Section,
+getMachOSection(const StringRef &Segment, const StringRef &Section,
                 unsigned TypeAndAttributes,
                 unsigned Reserved2, SectionKind Kind) const {
   // FIXME: UNIQUE HERE.