Index: include/llvm/ADT/StringRef.h
===================================================================
--- include/llvm/ADT/StringRef.h
+++ include/llvm/ADT/StringRef.h
@@ -40,6 +40,7 @@
   class StringRef {
   public:
     typedef const char *iterator;
+    typedef const unsigned char *uiterator;
     typedef const char *const_iterator;
     static const size_t npos = ~size_t(0);
     typedef size_t size_type;
@@ -88,8 +89,10 @@
     /// @{
 
     iterator begin() const { return Data; }
+    uiterator ubegin() const { return reinterpret_cast<uiterator>(begin()); }
 
     iterator end() const { return Data + Length; }
+    uiterator uend() const { return reinterpret_cast<uiterator>(end()); }
 
     /// @}
     /// @name String Operations
Index: include/llvm/IR/Metadata.h
===================================================================
--- include/llvm/IR/Metadata.h
+++ include/llvm/IR/Metadata.h
@@ -55,12 +55,15 @@
   unsigned getLength() const { return (unsigned)getName().size(); }
 
   typedef StringRef::iterator iterator;
+  typedef StringRef::uiterator uiterator;
 
   /// \brief Pointer to the first byte of the string.
   iterator begin() const { return getName().begin(); }
+  uiterator ubegin() const { return getName().ubegin(); }
 
   /// \brief Pointer to one byte past the end of the string.
   iterator end() const { return getName().end(); }
+  uiterator uend() const { return getName().uend(); }
 
   /// \brief Methods for support type inquiry through isa, cast, and dyn_cast.
   static bool classof(const Value *V) {