On Fri, Jan 29, 2021 at 4:46 PM 'Nick Desaulniers' via Clang Built
Linux [off-list ref] wrote:

On Fri, Jan 29, 2021 at 4:08 PM Sedat Dilek [off-list ref] wrote:

quoted

On Fri, Jan 29, 2021 at 8:43 PM Nick Desaulniers
[off-list ref] wrote:

quoted

DWARF v5 is the latest standard of the DWARF debug info format.

DWARF5 wins significantly in terms of size and especially so when mixed
with compression (CONFIG_DEBUG_INFO_COMPRESSED).

Link: http://www.dwarfstd.org/doc/DWARF5.pdf

Patch 1 is a cleanup that lays the ground work and isn't DWARF
v5 specific.
Patch 2 implements Kconfig and Kbuild support for DWARFv5.

When you will do a v7...

Can you look also at places where we have hardcoded DWARF-2 handling...

Ah, sorry, I just saw this now, after sending v7.  Can we wait to
purge DWARF v2 until after we have DWARF v5?

In fact, if they are orthogonal like I suspect, why don't you send
some patches and I will help you test them?
--
Thanks,
~Nick Desaulniers

Basically the distinction is just between DWARF v2 .debug_line and
DWARF v5 .debug_line .
(-gdwarf-4 adds an extra maximum_operations_per_instruction (constant
1) compared with -gdwarf-2 but that can mostly be ignored).

Refinement among -gdwarf-[234] just clarifies things and is not going
to affect debugging experience in any case.
So I agree with Nick that it can be done separately.
Note: such clarification can make things a bit ugly because binutils
before 2020 does not recognize -gdwarf-[345].



-- 
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