1 files changed, 28 insertions, 32 deletions

diff --git a/include/llvm/ADT/StringSwitch.h b/include/llvm/ADT/StringSwitch.h
index 6562d57..7dd5647 100644
--- a/include/llvm/ADT/StringSwitch.h
+++ b/include/llvm/ADT/StringSwitch.h
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===/
 //
 //  This file implements the StringSwitch template, which mimics a switch()
-//  statements whose cases are string literals.
+//  statement whose cases are string literals.
 //
 //===----------------------------------------------------------------------===/
 #ifndef LLVM_ADT_STRINGSWITCH_H
@@ -18,7 +18,7 @@
 #include <cstring>
 
 namespace llvm {
-  
+
 /// \brief A switch()-like statement whose cases are string literals.
 ///
 /// The StringSwitch class is a simple form of a switch() statement that
@@ -35,48 +35,44 @@ namespace llvm {
 ///   .Case("green", Green)
 ///   .Case("blue", Blue)
 ///   .Case("indigo", Indigo)
-///   .Case("violet", Violet)
+///   .Cases("violet", "purple", Violet)
 ///   .Default(UnknownColor);
 /// \endcode
-template<typename T>
+template<typename T, typename R = T>
 class StringSwitch {
   /// \brief The string we are matching.
   StringRef Str;
-  
-  /// \brief The result of this switch statement, once known.
-  T Result;
-  
-  /// \brief Set true when the result of this switch is already known; in this
-  /// case, Result is valid.
-  bool ResultKnown;
-  
+
+  /// \brief The pointer to the result of this switch statement, once known,
+  /// null before that.
+  const T *Result;
+
 public:
-  explicit StringSwitch(StringRef Str) 
-  : Str(Str), ResultKnown(false) { }
-  
+  explicit StringSwitch(StringRef Str)
+  : Str(Str), Result(0) { }
+
   template<unsigned N>
   StringSwitch& Case(const char (&S)[N], const T& Value) {
-    if (!ResultKnown && N-1 == Str.size() && 
+    if (!Result && N-1 == Str.size() &&
         (std::memcmp(S, Str.data(), N-1) == 0)) {
-      Result = Value;
-      ResultKnown = true;
+      Result = &Value;
     }
-    
+
     return *this;
   }
-  
+
   template<unsigned N0, unsigned N1>
   StringSwitch& Cases(const char (&S0)[N0], const char (&S1)[N1],
                       const T& Value) {
     return Case(S0, Value).Case(S1, Value);
   }
-  
+
   template<unsigned N0, unsigned N1, unsigned N2>
   StringSwitch& Cases(const char (&S0)[N0], const char (&S1)[N1],
                       const char (&S2)[N2], const T& Value) {
     return Case(S0, Value).Case(S1, Value).Case(S2, Value);
   }
-  
+
   template<unsigned N0, unsigned N1, unsigned N2, unsigned N3>
   StringSwitch& Cases(const char (&S0)[N0], const char (&S1)[N1],
                       const char (&S2)[N2], const char (&S3)[N3],
@@ -87,21 +83,21 @@ public:
   template<unsigned N0, unsigned N1, unsigned N2, unsigned N3, unsigned N4>
   StringSwitch& Cases(const char (&S0)[N0], const char (&S1)[N1],
                       const char (&S2)[N2], const char (&S3)[N3],
-                       const char (&S4)[N4], const T& Value) {
+                      const char (&S4)[N4], const T& Value) {
     return Case(S0, Value).Case(S1, Value).Case(S2, Value).Case(S3, Value)
       .Case(S4, Value);
   }
-  
-  T Default(const T& Value) {
-    if (ResultKnown)
-      return Result;
-    
+
+  R Default(const T& Value) const {
+    if (Result)
+      return *Result;
+
     return Value;
   }
-  
-  operator T() {
-    assert(ResultKnown && "Fell off the end of a string-switch");
-    return Result;
+
+  operator R() const {
+    assert(Result && "Fell off the end of a string-switch");
+    return *Result;
   }
 };