Issue 221203.1: Remove suggestion that DW_FORM_sec_offset may not be used for lists in splitunit

Author:	David Blaikie
Champion:	David Blaikie
Date submitted:	2022-12-03
Date revised:	2025-03-17
Date closed:	2024-05-13
Type:	Error
Status:	Accepted
DWARF version:	6

Section 7.28,7.29, pg 242,244

Both 7.28 (Range List Table) and 7.29 (Location List Table) mention, in a non-normative comment:

"[use of rnglistx] is necessary in split units and may be more compact than using DW_FORM_sec_offset in non-split units"

But figure B.2 (page 278, explained on page 280) says that DW_FORM_sec_offset may be used to reference .debug_rnglists.dwo from .debug_info.dwo.

I think the latter is correct & the former non-normative comments should be removed/amended.

In addition, we should clarify what DW_FORM_sec_offset means in Split Units.

• Remove DW_AT_rnglists_base and DW_AT_str_offsets_base from the list on page 68 of attributes inherited by the split full unit from the skeleton unit. (we might've already done this in the DWARFv6 draft for other reasons - neither should be inherited, they were sort of implied zero instead, but let's remove the implication and have them explicit)

• Table F.1 should include a checkmark in the split full column for DW_AT_loclists_base, DW_AT_rnglists_base, and DW_AT_str_offsets_base

• At the end of 3.1.3, page 68, note that:

  Use of DW_FORM_sec_offset and other equivalent encodings (eg: the abbrev offset in a compilation unit header) are resolved relative to the beginning of the contribution of the relevant section within the dwo or dwp file and cannot be used for sharing content between multiple compilation units. DW_FORM_sec_offset may not be used to when a reference to content in the skeleton unit is required (as the value present in the dwo file could not be relocated during linking of the skeleton units), such as for the addrptr class.

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2023-10-13: Revised to disallow the form.

2023-10-30: Revisited original proposal. Perhaps the form should be allowed, but add wording explaining how it applies in a .dwo and .dwp file.

2023-12-11: Revised based on original proposal. Added clarifications for split units.

2024-05-13: Accepted.

2025-03-17: Partially rescinded by 250311.1. In Table F.1, there should be no checkmark for DW_AT_loclists_base, DW_AT_rnglists_base, or DW_AT_str_offsets_base (now DW_AT_str_offsets) in the "Skeleton" column.