llvm-mc: Clean up some handling of symbol/section association to be more correct
(external was really undefined and there wasn't an explicit representation for
absolute symbols).
 - This still needs some cleanup to how the absolute "pseudo" section is dealt
   with, but I haven't figured out the nicest approach yet.

llvm-svn: 79733
7 files changed
tree: 303c56cf9fc2f25ad601d6748f6e84a520fe9141
  1. clang/
  2. compiler-rt/
  3. llvm/