https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65798
--- Comment #2 from Ian Lance Taylor <ian at airs dot com> --- I don't see it as a good idea to ignore an empty file name, but I'm fine with ignoring a 0 PC, so that is what I will implement. Though I am definitely curious how they got a 0 PC from runtime.Caller.
