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Date:   Tue, 24 Nov 2020 11:46:13 -0600
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Arvind Sankar <nivedita@alum.mit.edu>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Jakub Jelinek <jakub@redhat.com>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-toolchains@vger.kernel.org,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Fangrui Song <maskray@google.com>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Dmitry Golovin <dima@golovin.in>,
        Alistair Delva <adelva@google.com>
Subject: Re: [PATCH v2 3/4] Kbuild: make DWARF version a choice
Message-ID: <20201124174613.GW2672@gate.crashing.org>
References: <CAK7LNAST0Ma4bGGOA_HATzYAmRhZG=x_X=8p_9dKGX7bYc2FMA@mail.gmail.com> <20201104005343.4192504-1-ndesaulniers@google.com> <20201104005343.4192504-4-ndesaulniers@google.com> <20201123232210.GA208735@rani.riverdale.lan> <20201124003357.GR2672@gate.crashing.org> <20201124165602.GA343230@rani.riverdale.lan>
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On Tue, Nov 24, 2020 at 11:56:02AM -0500, Arvind Sankar wrote:
> On Mon, Nov 23, 2020 at 06:33:57PM -0600, Segher Boessenkool wrote:
> > On Mon, Nov 23, 2020 at 06:22:10PM -0500, Arvind Sankar wrote:
> > > Btw, is -gsplit-dwarf at all useful for assembler files?
> > 
> > If you invoke the assembler via the compiler, with that flag it still
> > creates separate .o and .dwo files (via objcopy invocations as usual).
> > Whether that is useful depends on if you have any debug info that can
> > be split :-)
> 
> Right, the latter was what I was really asking :) We don't currently
> pass -gsplit-dwarf for assembler and I was wondering if that mattered.

If there is any debug info in the .s files, it will all end up in the .o
file, not a .dwo file.  That may matter aesthetically, and it can cost a
few bytes of disk space, but it doesn't matter functionally (GDB will
search in both places).


Segher