+/// Represents a range in source code.
+///
+/// SMRange is implemented using a half-open range, as is the convention in C++.
+/// In the string "abc", the range (1,3] represents the substring "bc", and the
+/// range (2,2] represents an empty range between the characters "b" and "c".
+class SMRange {
+public:
+ SMLoc Start, End;
+
+ SMRange() {}
+ SMRange(SMLoc St, SMLoc En) : Start(St), End(En) {
+ assert(Start.isValid() == End.isValid() &&
+ "Start and end should either both be valid or both be invalid!");
+ }
+
+ bool isValid() const { return Start.isValid(); }
+};
+
+} // end namespace llvm