Add comments for two CleanupKinds.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@230459 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/EHScopeStack.h

@@ -75,8 +75,14 @@ template <class T> struct DominatingPointer<T,false> : InvariantValue<T*> {};
 template <class T> struct DominatingValue<T*> : DominatingPointer<T> {};
 
 enum CleanupKind : unsigned {
+  /// Denotes a cleanup that should run when a scope is exited using exceptional
+  /// control flow (a throw statement leading to stack unwinding, ).
   EHCleanup = 0x1,
+
+  /// Denotes a cleanup that should run when a scope is exited using normal
+  /// control flow (falling off the end of the scope, return, goto, ...).
   NormalCleanup = 0x2,
+
   NormalAndEHCleanup = EHCleanup | NormalCleanup,
 
   InactiveCleanup = 0x4,