From: Segher Boessenkool <segher@kernel.crashing.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: "Fāng-ruì Sòng" <maskray@google.com>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"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>,
"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
Date: Tue, 1 Dec 2020 03:32:53 -0600 [thread overview]
Message-ID: <20201201093253.GJ2672@gate.crashing.org> (raw)
In-Reply-To: <CAK7LNAS_hxevOS7hKxepyCBVU-4j87Yf5Y8DB6mFq+4xuaz3AA@mail.gmail.com>
On Tue, Dec 01, 2020 at 12:38:16PM +0900, Masahiro Yamada wrote:
> > We can bump -Wa,-gdwarf-2 to -Wa,-gdwarf-3 since GNU actually emits
> > DWARF v3 DW_AT_ranges (see
> > https://sourceware.org/bugzilla/show_bug.cgi?id=26850 )
> > This can avoid the `warning: DWARF2 only supports one section per
> > compilation unit` warning for Clang.
That warning should be "there can be only one section with executable
code per translation unit", or similar.
> I am not a DWARF spec expert.
Neither am I.
> Please teach me.
>
> In my understanding, "DWARF2 only supports one section ..."
> is warned only when building .S files with LLVM_IAS=1
.S files are simply run through the C preprocessor first, and then given
to the assembler. The only difference there should be wrt debug info is
you could have some macros that expand to assembler debug statements.
> If this is due to the limitation of DWARF v2, why is it OK to
> build .c files with LLVM_IAS?
The compiler can of course make sure not to use certain constructs in
its generated assembler code, while the assembler will have to swallow
whatever the user wrote.
Segher
next prev parent reply other threads:[~2020-12-01 9:39 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 [this message]
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
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