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From: Tsukasa OI <>
To: Tsukasa OI <>,
	Ian Lance Taylor <>,
	Cary Coutant <>
Subject: [PATCH 0/1] gold: Suppress "unused" variable warning on Clang
Date: Mon, 26 Sep 2022 10:35:39 +0000	[thread overview]
Message-ID: <> (raw)



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:

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
prologue on yyscript.y.


Tsukasa OI (1):
  gold: Suppress "unused" variable warning on Clang

 gold/yyscript.y | 3 +++
 1 file changed, 3 insertions(+)

base-commit: c21736aed1d4877e090df60362413669dbdc391d

             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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