>> > Yep - unless someone has significant objections my plan is currently: >> > >> > Emit a v5 index with extension/non-standard extra column indexes >> > (specifically: DW_SECT_LOC and 9 and DW_SECT_MACINFO at 10). I hope those >> > can at least be reserved (like DW_SECT value 2 (originally DW_SECT_TYPES) >> > was in DWARFv5) in DWARFv6. & maybe open up an extension space in the >> > future. >> >> That sounds good to me. When I saw that number 2 (debug_types in the >> fission extension) was reserved, I originally assumed this was what >> had already happened.
The pre-v5 dwp format was just a prototype, accessed via --experimental GCC flags, and I don't think we ever intended to support mixing pre-v5 dwo files with standard v5 dwo files. I'd recommend your original option #1 (invalid/unsupported). Thus, you shouldn't need DW_SECT_LOC or DW_SECT_MACINFO. The .debug_types sections were moved back into .debug_info sections at the very last minute, so we just removed DW_SECT_TYPES without renumbering the later values. As best I recall, that was just a nod towards some compatibility with the prototype format, but it wasn't intended to provide for complete compatibility. I don't believe we ever supported .debug_macinfo in the prototype, so I wasn't concerned with the renumbering around DW_SECT_MACRO and DW_SECT_MACINFO. I agree that we should have reserved an extension range for DW_SECT values. It's probably safe to pick some arbitrarily large values if you need to extend this. For DWARF-64 support, I truly hoped that we wouldn't ever need it, but if it was ever necessary, the mechanism I had in mind was to simply replace .debug_cu_index sections with .debug_cu_index_64 sections (and likewise for .debug_tu_index). Maybe DWARF v6 will address this. Keep in mind that the .dwp can be an ELFCLASS64 object file, and its total size can grow larger than 4GB, even if .debug_cu_index can't support any section offsets larger than 4GB. -cary _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
