stap translator: tolerate NULLs coming from some elfutils string lookups
It was reported on the mailing list, and privately experienced, that
stap pass-2 crashes could occur due to NULL dwarf_diename or
dwarf_decl_file's being propagated rather far within stap. This
commit adds protections (of the form ?: "foo") to eliminate the
problem in a few spots. There may be others; we should not store
so many raw char*'s.
git://sourceware.org / systemtap.git / commit