Index: include/llvm/ADT/Twine.h
===================================================================
--- include/llvm/ADT/Twine.h
+++ include/llvm/ADT/Twine.h
@@ -7,12 +7,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_ADT_TWINE_H
-#define LLVM_ADT_TWINE_H
-
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Support/DataTypes.h"
-#include "llvm/Support/ErrorHandling.h"
+#ifndef LLVM_ADT_TWINE_H
+#define LLVM_ADT_TWINE_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cassert>
 #include <string>
 
@@ -97,12 +98,15 @@
       /// A pointer to an std::string instance.
       StdStringKind,
 
-      /// A pointer to a StringRef instance.
-      StringRefKind,
-
-      /// A char value reinterpreted as a pointer, to render as a character.
-      CharKind,
-
+      /// A pointer to a StringRef instance.
+      StringRefKind,
+
+      /// A pointer to a SmallString instance.
+      SmallStringKind,
+
+      /// A char value reinterpreted as a pointer, to render as a character.
+      CharKind,
+
       /// An unsigned int value reinterpreted as a pointer, to render as an
       /// unsigned decimal integer.
       DecUIKind,
@@ -133,12 +137,13 @@
     union Child
     {
       const Twine *twine;
-      const char *cString;
-      const std::string *stdString;
-      const StringRef *stringRef;
-      char character;
-      unsigned int decUI;
-      int decI;
+      const char *cString;
+      const std::string *stdString;
+      const StringRef *stringRef;
+      const SmallVectorImpl<char> *smallString;
+      char character;
+      unsigned int decUI;
+      int decI;
       const unsigned long *decUL;
       const long *decL;
       const unsigned long long *decULL;
@@ -286,12 +291,19 @@
     /*implicit*/ Twine(const StringRef &Str)
       : LHSKind(StringRefKind), RHSKind(EmptyKind) {
       LHS.stringRef = &Str;
-      assert(isValid() && "Invalid twine!");
-    }
-
-    /// Construct from a char.
-    explicit Twine(char Val)
-      : LHSKind(CharKind), RHSKind(EmptyKind) {
+      assert(isValid() && "Invalid twine!");
+    }
+
+    /// Construct from a SmallString.
+    /*implicit*/ Twine(const SmallVectorImpl<char> &Str)
+      : LHSKind(SmallStringKind), RHSKind(EmptyKind) {
+      LHS.smallString = &Str;
+      assert(isValid() && "Invalid twine!");
+    }
+
+    /// Construct from a char.
+    explicit Twine(char Val)
+      : LHSKind(CharKind), RHSKind(EmptyKind) {
       LHS.character = Val;
     }
 
@@ -399,12 +411,13 @@
 
       switch (getLHSKind()) {
       case EmptyKind:
-      case CStringKind:
-      case StdStringKind:
-      case StringRefKind:
-        return true;
-      default:
-        return false;
+      case CStringKind:
+      case StdStringKind:
+      case StringRefKind:
+      case SmallStringKind:
+        return true;
+      default:
+        return false;
       }
     }
 
@@ -432,12 +445,12 @@
       switch (getLHSKind()) {
       default: llvm_unreachable("Out of sync with isSingleStringRef");
       case EmptyKind:      return StringRef();
-      case CStringKind:    return StringRef(LHS.cString);
-      case StdStringKind:  return StringRef(*LHS.stdString);
-      case StringRefKind:  return *LHS.stringRef;
-      }
-    }
-
+      case CStringKind:    return StringRef(LHS.cString);
+      case StdStringKind:  return StringRef(*LHS.stdString);
+      case StringRefKind:  return *LHS.stringRef;
+      case SmallStringKind:return StringRef(LHS.smallString->data(),LHS.smallString->size());
+      }
+    }
     /// toStringRef - This returns the twine as a single StringRef if it can be
     /// represented as such. Otherwise the twine is written into the given
     /// SmallVector and a StringRef to the SmallVector's data is returned.
Index: include/llvm/Support/raw_ostream.h
===================================================================
--- include/llvm/Support/raw_ostream.h
+++ include/llvm/Support/raw_ostream.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_SUPPORT_RAW_OSTREAM_H
 #define LLVM_SUPPORT_RAW_OSTREAM_H
 
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
@@ -185,6 +186,10 @@
     return write(Str.data(), Str.length());
   }
 
+  raw_ostream &operator<<(const llvm::SmallVectorImpl<char> &Str) {
+    return write(Str.data(), Str.size());
+  }
+
   raw_ostream &operator<<(unsigned long N);
   raw_ostream &operator<<(long N);
   raw_ostream &operator<<(unsigned long long N);
Index: lib/Support/Twine.cpp
===================================================================
--- lib/Support/Twine.cpp
+++ lib/Support/Twine.cpp
@@ -69,12 +69,15 @@
   case Twine::StdStringKind:
     OS << *Ptr.stdString;
     break;
-  case Twine::StringRefKind:
-    OS << *Ptr.stringRef;
-    break;
-  case Twine::CharKind:
-    OS << Ptr.character;
-    break;
+  case Twine::StringRefKind:
+    OS << *Ptr.stringRef;
+    break;
+  case Twine::SmallStringKind:
+    OS << *Ptr.smallString;
+    break;
+  case Twine::CharKind:
+    OS << Ptr.character;
+    break;
   case Twine::DecUIKind:
     OS << Ptr.decUI;
     break;
@@ -119,12 +122,16 @@
        << Ptr.stdString << "\"";
     break;
   case Twine::StringRefKind:
-    OS << "stringref:\""
-       << Ptr.stringRef << "\"";
-    break;
-  case Twine::CharKind:
-    OS << "char:\"" << Ptr.character << "\"";
-    break;
+    OS << "stringref:\""
+       << Ptr.stringRef << "\"";
+    break;
+  case Twine::SmallStringKind:
+    OS << "smallstring:\""
+       << Ptr.smallString << "\"";
+    break;
+  case Twine::CharKind:
+    OS << "char:\"" << Ptr.character << "\"";
+    break;
   case Twine::DecUIKind:
     OS << "decUI:\"" << Ptr.decUI << "\"";
     break;