Hi, I have been pondering the various aranges proposals and how they interact with the change to merge the units proposal. It looks like the intent of two proposals is diminished by two other proposals.
To make it possible to quickly see whether an address (range) is covered by an ELF file containing DWARF information two proposals were made: aranges does not have debug info length http://dwarfstd.org/ShowIssue.php?issue=100430.1 debug_aranges and address-less CUs http://dwarfstd.org/ShowIssue.php?issue=100430.2 Together when adopted makes life for a debugger much easier. You would scan the .debug_aranges section, note the addresses, see whether all CUs from the .debug_info section are covered and then don't need to load any other information if no address match is found. Given that the main .debug_info/.debug_abbrev sections are often huge and that some programs contain lots of modules not having to map them all in is a great benefit. But then there are also the following proposals: Type Unit Merge http://dwarfstd.org/ShowIssue.php?issue=130526.1 Ambiguity in DWARF4 of debug_info_offset in .debug_aranges http://dwarfstd.org/ShowIssue.php?issue=100816.1 Together these proposals counter the first two proposals. Since when adopted the first would introduce type units in the main .debug_info section and then the second would remove .debug_aranges for those units. Which would bring us back to the original situation that you cannot just scan the .debug_aranges for an address and check whether all units in .debug_info are covered. So you will again need to load and scan them too when trying to match an address. Is there a way to reconcile these proposals so they keep the benefit of both (quick/complete address scan without having to load/parse bulk data and simplifying the DWARF data structures by combining various units in one section)? One way might be to reverse the last proposal. Instead of removing the aranges for type units (which did indeed not make much sense in the split .debug_info/.debug_type approach), add an empty aranges header if a type unit appears in .debug_info in the way of the second proposal for address-less CUs. Thanks, Mark _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
