diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 047627a5ff6..b4bc61b7243 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -988,8 +988,11 @@ static StringRef getDIEStringAttr(DIE *Die, unsigned Attr) {
 /// a trailing NULL with the string.
 static void addStringToHash(MD5 &Hash, StringRef Str) {
   DEBUG(dbgs() << "Adding string " << Str << " to hash.\n");
-  Hash.update(Str);
-  Hash.update('\0');
+  HashValue SVal((const uint8_t *)Str.data(), Str.size());
+  const uint8_t NB = '\0';
+  HashValue NBVal((const uint8_t *)&NB, 1);
+  Hash.update(SVal);
+  Hash.update(NBVal);
 }
 
 // FIXME: These are copied and only slightly modified out of LEB128.h.