[driver] Refactor a bit to enable a few fixes when generating diagnostics.  No functional change intended.

llvm-svn: 137524
2 files changed
tree: 22637cfade0ec69c9edd0215e0b5670da0378295
  1. clang/
  2. compiler-rt/
  3. debuginfo-tests/
  4. libcxx/
  5. libcxxabi/
  6. lldb/
  7. llvm/
  8. polly/