[Dwarf-Discuss] Split Dwarf vs. CU DW_AT_ranges / DW_AT_low_pc placement

[Jakub Jelinek]

On Thu, Mar 11, 2021 at 11:30:05AM -0800, David Blaikie wrote:
> Thanks! - is this proposed as a DWARF extension? I thought I remembered it

170427.1 I think.  Note, what is emitted is different from what is being
proposed, the problem with DW_LLE_* and DW_RLE_* is that they aren't easily
extensible (in a way that would allow consumers that don't know about the
extension skip it and parse just the standard ones; because when seeing
an unknown opcode, the consumer doesn't know what arguments if any it has).
E.g. in the way .debug_macro allows producers to define what arguments
extension opcodes have (how many and what DW_FORM_* each has).
So I think what GCC currently produces puts the stuff before the location
sequences such that if a consumer can't handle those, it can skip those.
The only thing that doesn't really work well for consumer unaware about that
extension is walking the whole .debug_rnglists and dumping everything that
it contains.

	Jakub