Major reorganization and extension of the code. The diff on this will be a

Major reorganization and extension of the code. The diff on this will be a
mess as functions were moved around into a better ordering. The code was
extended to provide various -gen-* options to better control what the
generated output should be. Currently it is possible to generate entire
modules (three different ways), functions, global variables, and types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28589 91177308-0d34-0410-b5e6-96231b3b80d8