From: Nick Desaulniers <ndesaulniers@google.com>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
linux-toolchains@vger.kernel.org
Subject: Re: [PATCH] Kbuild: implement support for DWARF5
Date: Thu, 3 Dec 2020 16:17:36 -0800 [thread overview]
Message-ID: <CAKwvOd=m9+CxsBuG_DLSx1gaMmOmpm05xeU353As_tPKUij2qA@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOd=U1mxfgep3KyoAJ3WBcsywdx9_wfVgLcgAhd-+kFfZhA@mail.gmail.com>
On Thu, Dec 3, 2020 at 2:56 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> On Tue, Nov 3, 2020 at 4:17 PM Arvind Sankar <nivedita@alum.mit.edu> wrote:
> >
> > On Tue, Nov 03, 2020 at 04:05:36PM -0800, Nick Desaulniers wrote:
> > > On Tue, Nov 3, 2020 at 4:00 PM Arvind Sankar <nivedita@alum.mit.edu> wrote:
> > > >
> > > > On Wed, Oct 21, 2020 at 06:21:06PM -0700, Nick Desaulniers wrote:
> > > > > Further -gdwarf-X where X is an unsupported value doesn't
> > > > > produce an error in $(CC).
> > > >
> > > > Do you have more details here? On godbolt.org, gcc does report an error
> > > > for unsupported dwarf versions.
> > > >
> > > > https://godbolt.org/z/G35798
> > > >
> > > > gcc does not seem to pass the -gdwarf-* options to the assembler when
> > > > compiling C source. For assembler, gcc will pass an appropriate option
> > > > depending on the version of binutils it was configured with: if the
> > > > assembler doesn't support dwarf-5 it can call it with --gdwarf2 for eg.
> > > >
> > > > If the user is using a properly configured toolchain it doesn't look
> > > > like it should be an issue to just use cc-option?
> > >
> > > I wrote the base patch back in May, and didn't revisit until recently.
> > > I could have sworn the cc-option silently failed for the check
> > > cc-option does, which is /dev/null input. I need to recheck that, but
> > > it doesn't hurt to simply include it for now, which I've done in a v2
> > > I'm about to send.
> > > --
> > > Thanks,
> > > ~Nick Desaulniers
> >
> > This is giving me deja vu about the -gz=zlib option.
> >
> > Didn't Masahiro fix the cc-option issue with
> > 4d0831e8a029 ("kconfig: unify cc-option and as-option")
> >
> > The existing -Wa,-gdwarf-2 in the Makefile seems bogus, btw. GCC 4.9.0
> > at least appears to pass on --gdwarf2 automatically.
>
> It looks like we don't need -Wa,-gdwarf-2 when -gdwarf-2 is set. So I
> can probably drop
> +DEBUG_CFLAGS += $(dwarf-aflag)
> from v2. Will retest though.
That's needed for non LLVM_IAS=1 builds so that clang informs GAS to
assembler using DWARF Version 5; otherwise every translation unit
fails to assemble with an error from GAS.
--
Thanks,
~Nick Desaulniers
prev parent reply other threads:[~2020-12-04 0:18 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 1:21 [PATCH] Kbuild: implement support for DWARF5 Nick Desaulniers
2020-10-22 1:44 ` Fangrui Song
2020-11-03 22:27 ` Nick Desaulniers
2020-10-28 18:18 ` Nick Desaulniers
2020-11-02 2:20 ` Masahiro Yamada
2020-11-02 8:18 ` Jakub Jelinek
2020-11-03 22:21 ` Nick Desaulniers
2020-11-04 12:19 ` Jakub Jelinek
2020-11-03 22:13 ` Nick Desaulniers
2020-11-04 0:53 ` [PATCH v2 0/4] Kbuild: DWARF v5 support Nick Desaulniers
2020-11-04 0:53 ` [PATCH v2 1/4] x86_64: Change .weak to SYM_FUNC_START_WEAK for arch/x86/lib/mem*_64.S Nick Desaulniers
2020-11-04 0:53 ` [PATCH v2 2/4] Kbuild: do not emit debug info for assembly with LLVM_IAS=1 Nick Desaulniers
2020-11-05 6:58 ` Nathan Chancellor
2020-11-05 7:26 ` Fangrui Song
2020-11-09 18:28 ` Nick Desaulniers
2020-11-09 18:35 ` [PATCH v3] " Nick Desaulniers
2020-11-16 23:41 ` Nick Desaulniers
[not found] ` <CA+SOCLJTg6U+Ddop_5O-baVR42va3vGAvMQ62o9H6rd+10aKrw@mail.gmail.com>
2020-11-23 18:42 ` Nick Desaulniers
2020-11-24 18:44 ` Masahiro Yamada
2020-11-04 0:53 ` [PATCH v2 3/4] Kbuild: make DWARF version a choice Nick Desaulniers
2020-11-05 5:58 ` kernel test robot
2020-11-23 23:22 ` Arvind Sankar
2020-11-24 0:33 ` Segher Boessenkool
2020-11-24 16:56 ` Arvind Sankar
2020-11-24 17:46 ` Segher Boessenkool
2020-11-30 18:04 ` Masahiro Yamada
2020-11-30 20:27 ` Fāng-ruì Sòng
2020-12-01 3:38 ` Masahiro Yamada
2020-12-01 9:32 ` Segher Boessenkool
2020-12-02 1:08 ` Fāng-ruì Sòng
2020-11-30 20:45 ` Nick Desaulniers
2020-12-01 4:17 ` Masahiro Yamada
2020-11-04 0:53 ` [PATCH v2 4/4] Kbuild: implement support for DWARF v5 Nick Desaulniers
2020-11-24 17:28 ` Arvind Sankar
2020-12-03 23:22 ` Nick Desaulniers
2020-12-03 23:28 ` Nick Desaulniers
2020-12-04 17:06 ` Arvind Sankar
2020-12-10 23:18 ` Nick Desaulniers
2020-12-11 0:29 ` Arvind Sankar
2020-12-01 1:56 ` Masahiro Yamada
2020-11-04 0:00 ` [PATCH] Kbuild: implement support for DWARF5 Arvind Sankar
2020-11-04 0:05 ` Nick Desaulniers
2020-11-04 0:17 ` Arvind Sankar
2020-12-03 22:56 ` Nick Desaulniers
2020-12-04 0:17 ` Nick Desaulniers [this message]
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