utils/CmpDriver: add brief documentation to indicate what this does

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209268 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/utils/CmpDriver b/utils/CmpDriver
index 2533f547e973c6b905995bc2c9509e48cf4e5fa6..12ce7a3250f66b71d0c01b72cd58d2009b84c6ab 100755 (executable)
--- a/utils/CmpDriver
+++ b/utils/CmpDriver
@@ -1,5 +1,10 @@
 #!/usr/bin/env python
 
+"""
+A simple utility that compares tool invocations and exit codes issued by
+compiler drivers that support -### (e.g. gcc and clang).
+"""
+
 import subprocess
 
 def splitArgs(s):