Add a comment and some tests including the NULL byte.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182900 91177308-0d34-0410-b5e6-96231b3b80d8
Reformat comments here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182901 91177308-0d34-0410-b5e6-96231b3b80d8
Formatting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182902 91177308-0d34-0410-b5e6-96231b3b80d8
Rename variable to be more descriptive.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182903 91177308-0d34-0410-b5e6-96231b3b80d8