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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Joe Perches' <joe@perches.com>,
        Matthew Maurer <mmaurer@google.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        "Wedson Almeida Filho" <wedsonaf@gmail.com>
CC:     Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?iso-8859-1?Q?Bj=F6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Benno Lossin <benno.lossin@proton.me>,
        Andreas Hindborg <a.hindborg@samsung.com>,
        "Alice Ryhl" <aliceryhl@google.com>,
        "rust-for-linux@vger.kernel.org" <rust-for-linux@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] rust: Use awk instead of recent xargs
Thread-Topic: [PATCH] rust: Use awk instead of recent xargs
Thread-Index: AQHZ8kr/VXhkUs4M10WbSSTh7+OPhLAyVEjw
Date:   Fri, 29 Sep 2023 21:36:06 +0000
Message-ID: <be10d55a785d4d9b983b2dae6ed65942@AcuMS.aculab.com>
References: <20230928202116.2298150-1-mmaurer@google.com>
 <106c8bdb960da1568d0b3879efa76cd2acec032e.camel@perches.com>
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From: Joe Perches
> Sent: 28 September 2023 21:33
> 
> On Thu, 2023-09-28 at 20:21 +0000, Matthew Maurer wrote:
> > `awk` is already required by the kernel build, and the `xargs` feature
> > used in current Rust detection is not present in all `xargs` (notably,
> > toybox based xargs, used in the Android kernel build).
> []
> > diff --git a/rust/Makefile b/rust/Makefile
> []
> > @@ -365,8 +365,7 @@ quiet_cmd_exports = EXPORTS $@
> >        cmd_exports = \
> >  	$(NM) -p --defined-only $< \
> >  		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
> > -		| xargs -Isymbol \
> > -		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
> > +		| awk 'NF {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$0}' > $@
> 
> Perhaps remove the cut as well and use $$3 instead of $$0 ?
> Maybe integrate the grep as well.

Or keep the grep and use a shell loop?
	grep -E ' (T|R|D) ' | while read val flag symbol; do \
		echo "EXPORT_SYMBOL_RUST_GPL($symbol);"; done

(The grep is typically much faster than a shell conditional.)

	David

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