Add a bit of explanation for FrontendActionFactory.

Also use the more common "derive from" in place of "extend" in another
comment.

llvm-svn: 188440

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/include/clang/Tooling/Tooling.h b/clang/include/clang/Tooling/Tooling.h
index 9b3572a0fed..7e2be8a8ed3 100644
--- a/clang/include/clang/Tooling/Tooling.h
+++ b/clang/include/clang/Tooling/Tooling.h
@@ -54,6 +54,9 @@ class FrontendAction;
 namespace tooling {
 
 /// \brief Interface to generate clang::FrontendActions.
+///
+/// Having a factory interface allows, for example, a new FrontendAction to be
+/// created for each translation unit processed by ClangTool.
 class FrontendActionFactory {
 public:
   virtual ~FrontendActionFactory();
@@ -66,7 +69,7 @@ public:
 
 /// \brief Returns a new FrontendActionFactory for a given type.
 ///
-/// T must extend clang::FrontendAction.
+/// T must derive from clang::FrontendAction.
 ///
 /// Example:
 /// FrontendActionFactory *Factory =