Make assertion message more helpful in a case that might happen...


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7975 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/Support/CommandLine.h b/include/Support/CommandLine.h
index 4103617..dcd3b5b 100644
--- a/include/Support/CommandLine.h
+++ b/include/Support/CommandLine.h
@@ -642,7 +642,8 @@
 
   void check() {
     assert(Location != 0 && "cl::location(...) not specified for a command "
-           "line option with external storage!");
+           "line option with external storage, "
+           "or cl::init specified before cl::location()!!");
   }
 public:
   opt_storage() : Location(0) {}