Move somewhat messy conditional out of line.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187843 91177308-0d34-0410-b5e6-96231b3b80d8
Add a way to grab a particular attribute out of a DIE.
Use it when we're looking for a string in particular. Update comments
as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187844 91177308-0d34-0410-b5e6-96231b3b80d8