core: Record if a CU has a DW_TAG_unspecified_type

So that the BTF encoder can turn such functions into returning void
instead, as BTF doesn't have a representation for such tags.

First noticed with Linux circa v6.1 built with GNU AS 2.39.50, git
HEAD at the time building a .S file where the entry_ibpb assembly
"function" was encoded as DWARF with DW_TAG_unspecified_type as its
return type.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2 files changed