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Date:   Fri, 26 Aug 2022 11:10:32 -0700
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Message-ID: <20220826181035.859042-1-ndesaulniers@google.com>
Subject: [PATCH 0/3] fix debug info for asm and DEBUG_INFO_SPLIT
From:   Nick Desaulniers <ndesaulniers@google.com>
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     Michal Marek <michal.lkml@markovi.net>,
        Nathan Chancellor <nathan@kernel.org>,
        Tom Rix <trix@redhat.com>, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev, x86@kernel.org,
        Dmitrii Bundin <dmitrii.bundin.a@gmail.com>,
        Fangrui Song <maskray@google.com>,
        Alexey Alexandrov <aalexand@google.com>,
        Bill Wendling <morbo@google.com>,
        Greg Thelen <gthelen@google.com>,
        Nick Desaulniers <ndesaulniers@google.com>
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Alexey reported that the fraction of unknown filename instances in
kallsyms grew from ~0.3% to ~10% recently; Bill and Greg tracked it down
to assembler defined symbols, which regressed as a result of:

commit b8a9092330da ("Kbuild: do not emit debug info for assembly with LLVM_IAS=1")

In that commit, I allude to restoring debug info for assembler defined
symbols in a follow up patch, but it seems I forgot to do so in

commit a66049e2cf0e ("Kbuild: make DWARF version a choice")

Do so requires a fixup for as-option, which seems to be failing when
used in scripts/Makefile.debug.

Also includes a fix for DEBUG_INFO_SPLIT while I'm here.  Dmitrii
reports that this has been broken since gcc-11+ & clang-12+. I'm
guessing no one uses this .config option...since no one else has
reported it being broken yet...

Nick Desaulniers (3):
  Makefile.compiler: s/KBUILD_CFLAGS/KBUILD_AFLAGS/ for as-option
  Makefile.debug: re-enable debug info for .S files
  Makefile.debug: set -g unconditional on CONFIG_DEBUG_INFO_SPLIT

 arch/x86/boot/compressed/Makefile |  5 +++--
 scripts/Makefile.compiler         |  6 +++---
 scripts/Makefile.debug            | 26 +++++++++++++++++++-------
 3 files changed, 25 insertions(+), 12 deletions(-)

-- 
2.37.2.672.g94769d06f0-goog