[Bug debug/112656] btf: function prototypes generated with name

[ibhagat at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112656

--- Comment #7 from Indu Bhagat <ibhagat at gcc dot gnu.org> ---
Currently generating everything at finish () when -mco-re is in effect is
sufficient for BPF needs.  BTF is generated late for -mco-re because of CO-RE
relocations: these are strings which record indexes into the source-level data
structures, e.g. "0:4:2:3", and are stored int the .BTF string table.  CO-RE is
handled in the BPF backend during expand, which is after debug_early_finish ().

'Whether we should split BTF generation into two parts' is a larger question
not affecting the current PR at hand, I think. We should evaluate the overall
benefit of that approach (apart from the one we are seeing here - reproducible
BTF across targets), vs the implementation cost and complexity. If there is
interest.