On Sat, Feb 6, 2021 at 1:05 PM Masahiro Yamada [off-list ref] wrote:

On Sat, Feb 6, 2021 at 6:00 AM Sedat Dilek [off-list ref] wrote:

quoted

On Fri, Feb 5, 2021 at 9:22 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 places the DWARF v5 sections explicitly in the kernel linker
script.
Patch 2 modifies Kconfig for DEBUG_INFO_DWARF4 to be used as a fallback.
Patch 3 adds an explicit Kconfig for DWARF v5 for clang and older GCC
where the implicit default DWARF version is not 5.

Changes from v8:
* Separate out the linker script changes (from v7 0002). Put those
  first. Carry Reviewed by and tested by tags.  Least contentious part
  of the series. Tagged for stable; otherwise users upgrading to GCC 11
  may find orphan section warnings from the implicit default DWARF
  version changing and generating the new debug info sections.
* Add CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT in 0002, make it the
  default rather than CONFIG_DEBUG_INFO_DWARF4, as per Mark, Jakub,
  Arvind.
* Drop reviewed by and tested by tags for 0002 and 0003; sorry
  reviewers/testers, but I view that as a big change. I will buy you
  beers if you're fatigued, AND for the help so far. I appreciate you.

All 3 patches NACKed - I drink no beer.

LoL.
Other than beer, I am fine with v9.

Personally, I thought v8 (no CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT)
was good too, but I do not have a strong opinion about
leaving the compiler's freedom to choose the dwarf version.

Unless somebody has an objection, I will pick up v9 for the next MW.


Meanwhile, if you want to give reviewed-by / tested-by
please do so.

Fine with me.

I have no opinion towards distro-handling of toolchain-default(s).

Feel free to add my:
Tested-by: Sedat Dilek <redacted> # LLVM/Clang v12.0.0-rc1 x86-64

Thanks to all involved people - I enjoyed the evolution of this patchset.

- Sedat -

P.S.: /me drinking right now an Earl Grey tea - drink whatever you prefer :-).