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From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: 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>,
	Nick Desaulniers <ndesaulniers@google.com>,
	stable@vger.kernel.org
Subject: [PATCH v3] Kbuild: do not emit debug info for assembly with LLVM_IAS=1
Date: Mon,  9 Nov 2020 10:35:28 -0800	[thread overview]
Message-ID: <20201109183528.1391885-1-ndesaulniers@google.com> (raw)
In-Reply-To: <CAKwvOd=9iqLgdtAWe2h-9n=KUWm_rjCCJJYeop8PS6F+AA0VtA@mail.gmail.com>

Clang's integrated assembler produces the warning for assembly files:

warning: DWARF2 only supports one section per compilation unit

If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for
assembly sources (it is still emitted for C sources).  This will be
re-enabled for newer DWARF versions in a follow up patch.

Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with
LLVM=1 LLVM_IAS=1 for x86_64 and arm64.

Cc: <stable@vger.kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/716
Reported-by: Dmitry Golovin <dima@golovin.in>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Dmitry Golovin <dima@golovin.in>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Makefile b/Makefile
index f353886dbf44..7e899d356902 100644
--- a/Makefile
+++ b/Makefile
@@ -826,7 +826,9 @@ else
 DEBUG_CFLAGS	+= -g
 endif
 
+ifneq ($(LLVM_IAS),1)
 KBUILD_AFLAGS	+= -Wa,-gdwarf-2
+endif
 
 ifdef CONFIG_DEBUG_INFO_DWARF4
 DEBUG_CFLAGS	+= -gdwarf-4
-- 
2.29.2.222.g5d2a92d10f8-goog


  reply	other threads:[~2020-11-09 18:35 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           ` Nick Desaulniers [this message]
2020-11-16 23:41             ` [PATCH v3] " 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

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