and take care of standard bookkeeping that applies to every pass.
The theory of operation is that each pass defines a structure that
-represents everything we need to know about that pass --- when it
+represents everything we need to know about that pass---when it
should be run, how it should be run, what intermediate language
form or on-the-side data structures it needs. We register the pass
to be run in some particular order, and the pass manager arranges