Index: include/lld/ReaderWriter/Utils.h
===================================================================
--- include/lld/ReaderWriter/Utils.h    (revision 0)
+++ include/lld/ReaderWriter/Utils.h    (working copy)
@@ -0,0 +1,14 @@
+#include "llvm/ADT/StringExtras.h"
+
+namespace lld {
+  struct StringRefMapInfo {
+    static StringRef getEmptyKey() { return StringRef(); }
+    static StringRef getTombstoneKey() { return StringRef(" ", 0); }
+    static unsigned getHashValue(StringRef const val) {
+      return llvm::HashString(val);
+    }
+    static bool isEqual(StringRef const lhs, StringRef const rhs) {
+      return lhs.equals(rhs);
+    }
+  };
+}
Index: lib/ReaderWriter/FileArchive.cpp
===================================================================
--- lib/ReaderWriter/FileArchive.cpp    (revision 232608)
+++ lib/ReaderWriter/FileArchive.cpp    (working copy)
@@ -11,6 +11,7 @@
 #include "lld/Core/LLVM.h"
 #include "lld/Core/LinkingContext.h"
 #include "lld/Core/Parallel.h"
+#include "lld/ReaderWriter/Utils.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Object/Archive.h"
@@ -243,7 +244,8 @@
     return std::error_code();
   }

-  typedef std::unordered_map<StringRef, Archive::child_iterator> MemberMap;
+  typedef llvm::DenseMap<StringRef, Archive::child_iterator,
+      StringRefMapInfo> MemberMap;
   typedef std::set<const char *> InstantiatedSet;

   std::shared_ptr<MemoryBuffer> _mb;