From: Tsukasa OI <research_trasio@irq.a4lg.com>
To: Tsukasa OI <research_trasio@irq.a4lg.com>,
Ian Lance Taylor <iant@google.com>,
Cary Coutant <ccoutant@gmail.com>
Cc: binutils@sourceware.org
Subject: [PATCH 0/1] gold: Suppress "unused" variable warning on Clang
Date: Mon, 26 Sep 2022 10:35:39 +0000 [thread overview]
Message-ID: <cover.1664188522.git.research_trasio@irq.a4lg.com> (raw)
Hello,
[Background]
When we build Binutils and GDB with Clang, it causes a build failure due to
warnings generated by Clang and the default -Werror configuration.
I MOSTLY managed to make ALL ARCHITECTURE ENABLED Binutils and GDB
-Werror-free on Clang 15.0.0 (note that this does not necessarily mean
warning-free) and this patchset is a part of it (GNU gold).
- It still requires -Wno-implicit-function-declaration
on the LatticeMicro32 and M32R simulators. Except them, all Binutils /
GDB components can be built with Clang by default with my tree.
Full Clang 15.0.0 -Werror-free branch in development is available at:
<https://github.com/a4lg/binutils-gdb/tree/clang-nowarn-dev>
Tested configuration:
- Ubuntu 22.04.1 LTS (x86_64)
- LLVM / Clang 15.0.0 (built from source)
- Configuration examples:
$srcdir/configure \
--enable-targets=all \
--enable-multilib --enable-ld --enable-gold --enable-nls \
CC=clang CXX=clang++ CCLD=clang CXXLD=clang++ \
CFLAGS=' -O2 -g -Wno-implicit-function-declaration' \
CXXFLAGS='-O2 -g -Wno-implicit-function-declaration'
$srcdir/configure \
--target=riscv64-unknown-linux-gnu \
--enable-multilib --enable-ld --enable-gold --enable-nls \
CC=clang CXX=clang++ CCLD=clang CXXLD=clang++ \
CFLAGS='-O2 -g' CXXFLAGS='-O2 -g'
[About this Patch]
Clang generates a warning if there is a variable that is set but not used
otherwise ("-Wunused-but-set-variable"). On the default configuration, it
causes a build failure (unless "--disable-werror" is specified).
Because the cause of this error is in the Bison-generated code
($(binutils)/gold/yyscript.y -> $(srcdir)/gold/yyscript.c),
this commit suppresses this warning ("-Wunused-but-set-variable") by placing
DIAGNOSTIC_IGNORE_UNUSED_BUT_SET_VARIABLE macro at the end of user
prologue on yyscript.y.
Thanks,
Tsukasa
Tsukasa OI (1):
gold: Suppress "unused" variable warning on Clang
gold/yyscript.y | 3 +++
1 file changed, 3 insertions(+)
base-commit: c21736aed1d4877e090df60362413669dbdc391d
--
2.34.1
next reply other threads:[~2022-09-26 10:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-26 10:35 Tsukasa OI [this message]
2022-09-26 10:35 ` [PATCH 1/1] " Tsukasa OI
2022-09-27 1:05 ` Alan Modra
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