Show-ing GHC internal data structures

I'm working with a friend on a project that involves hacking at the GHC internals. We'd like to be able to print some of the large data structures involved -- specifically a TcGblEnv. TcGblEnv is a record with a number of fields of different types, and it would be silly to go through the source adding "deriving Show" to the end of each type definition. It seems like Show instances for internal data structures would be useful for the GHC developers (for debugging purposes -- perhaps they were left out of the GHC distribution to keep the compiled code small?), and we were wondering if anyone had the relevant instance declarations lying around. Thanks, David