Use proper return type for attribute index.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173638 91177308-0d34-0410-b5e6-96231b3b80d8
Use proper return type for attribute index.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173639 91177308-0d34-0410-b5e6-96231b3b80d8
Improve the debug output a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173640 91177308-0d34-0410-b5e6-96231b3b80d8