and expose the necessary hooks in the API directly.
This makes it much cleaner for example to log the usage of a pass
manager from a library. It also makes it more obvious that this
functionality isn't "optional" or "asserts-only" for the pass manager.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225841 91177308-0d34-0410-b5e6-96231b3b80d8