allow TimeRegion to take a potentially-null pointer to a

timer for clang.

llvm-svn: 64874

include/llvm/Support/Timer.h

@@ -113,14 +113,19 @@ private:
 /// the relevant timer.  This makes it easy to time a region of code.
 ///
 class TimeRegion {
-  Timer &T;
+  Timer *T;
   TimeRegion(const TimeRegion &); // DO NOT IMPLEMENT
 public:
-  explicit TimeRegion(Timer &t) : T(t) {
-    T.startTimer();
+  explicit TimeRegion(Timer &t) : T(&t) {
+    T->startTimer();
+  }
+  explicit TimeRegion(Timer *t) : T(t) {
+    if (T)
+      T->startTimer();
   }
   ~TimeRegion() {
-    T.stopTimer();
+    if (T)
+      T->stopTimer();
   }
 };