Re: [PATCH v9 0/3] Kbuild: DWARF v5 support

From: Masahiro Yamada <masahiroy@kernel.org>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Jakub Jelinek <jakub@redhat.com>,
	Fangrui Song <maskray@google.com>,
	Caroline Tice <cmtice@google.com>,
	Nick Clifton <nickc@redhat.com>, Yonghong Song <yhs@fb.com>,
	Jiri Olsa <jolsa@kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Arvind Sankar <nivedita@alum.mit.edu>,
	Chris Murphy <bugzilla@colorremedies.com>,
	Mark Wielaard <mark@klomp.org>
Subject: Re: [PATCH v9 0/3] Kbuild: DWARF v5 support
Date: Sat, 6 Feb 2021 21:04:16 +0900	[thread overview]
Message-ID: <CAK7LNAT8rjo=MdLqpjRXR2fnJ8XSeoA=uD633Pj1ENs5JOciXQ@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUW3sg_PkbmKSFMs6EqwQV7=hvKuAgZSsbg=Qr6gTs7RbQ@mail.gmail.com>

On Sat, Feb 6, 2021 at 6:00 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> On Fri, Feb 5, 2021 at 9:22 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
> >
> > 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.

-- 
Best Regards
Masahiro Yamada