These diagnostics aren't perfect - in the case of merging several dwos
into dwps and those dwps into more dwps - just getting the message about
the original source file name might not be much help (since it's the
same in both dwos, by definition - but doesn't tell you which chain of
dwps to backtrack)
It might be worth adding the DW_AT_dwo_id to the split debug info to
improve the diagnostic experience - might help track down the duplicates
better.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261988 91177308-0d34-0410-b5e6-96231b3b80d8