This trips over a few other limitations, but in the interests of incremental development I'm starting here & I'll look at the issues with -verify and filesystem checks (the fact that the behavior depends on the existence of a 'foo' directory even though it shouldn't need it), etc.
Reviewers: rsmith
Differential Revision: https://reviews.llvm.org/D61656
llvm-svn: 360195
David Blaikie