[PATCH] Add a new pass to compute DWARF path discriminators.

[Eric Christopher]

  One more split I think, the pass, the two helper functions, and table can be separate from the rest of it. It would be nice to see the patch without them using some discriminator information to make sure that we emit the right code.

http://llvm-reviews.chandlerc.com/D2691

BRANCH
  discriminator-pass

ARCANIST PROJECT
  llvm