TableGen: More helpful error messages

Change-Id: Ic78afd0cd765fdb4cf1b7ecfb6bba22653ce6d29

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327118 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed