This patch started as an attempt to rebase Greg's differential (D32821).
The result is both quite similar and different at the same time. It adds
the following checks:
- Verify that all address ranges in a DIE are valid.
- Verify that no ranges within the DIE overlap.
- Verify that no ranges overlap with the ranges of a sibling.
- Verify that children are completely contained in its (direct)
parent's address range. (unless both are subprograms)
Differential revision: https://reviews.llvm.org/D37696
llvm-svn: 313255