Bug 28574 - Reduce the size of struct line_state and Dwarf_Line_s
Summary: Reduce the size of struct line_state and Dwarf_Line_s
Status: NEW
Alias: None
Product: elfutils
Classification: Unclassified
Component: libdw (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
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Reported: 2021-11-10 09:27 UTC by Mark Wielaard
Modified: 2021-11-10 09:27 UTC (History)
1 user (show)

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Description Mark Wielaard 2021-11-10 09:27:15 UTC 
struct line_state and Dwarf_Line_s contain various fields which are often never used. op_index, isa, discriminator and for the linemap extensions context and functionname. On the other hand it doesn't contain some of the DWARF5 additions like the md5sum.

For DWARF5 we should be able to just have the fields that are actually defined. For DWARF4 and below we should at least try to get away with just the most used fields and only use extended records for the lesser (never) used fields.

See also the discussion here:
https://sourceware.org/pipermail/elfutils-devel/2021q3/004198.html

Note that there is a DWARF6 proposal to have "optional" records in file name tables:
https://dwarfstd.org/ShowIssue.php?issue=211108.2