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From: Maxime Devos <maximedevos@telenet.be>
To: Tobias Kortkamp <tobias.kortkamp@gmail.com>, 55541@debbugs.gnu.org
Subject: [bug#55541] [PATCH] gnu: Add azpainter.
Date: Fri, 20 May 2022 18:00:22 +0200	[thread overview]
Message-ID: <ad892524dd4d37ff3e0544fbd56fdcc37fef3690.camel@telenet.be> (raw)
In-Reply-To: <6d31ff958ec0c75cbba8324a275315d195a54902.1653045472.git.tobias.kortkamp@gmail.com>

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Tobias Kortkamp schreef op vr 20-05-2022 om 13:18 [+0200]:
> +    (build-system gnu-build-system) ;actually a home grown build system
> +    (arguments
> +     (list #:tests? #f
> +           #:phases
> +           #~(modify-phases %standard-phases
> +               (replace 'configure
> +                 (lambda _
> +                   (invoke "./configure"
> +                           (string-append "--prefix="
> +                                          #$output))))

As-is, this home-grown build system is broken when cross-compiling:

  * When cross-compiling, TARGET-gcc needs to be used instead of gcc.
    Maybe do (setenv "CC" #$(cc-for-target)) first?

  * Likewise, TARGET-pkg-config instead of pkg-config (not 100% sure)

  * It tries to run binaries during ./configure.  When cross-compiling,
    ./conftest will always fail (unless using emulation) and hence
    always detect ‘little endian’ but this is incorrect when
    cross-compiling for big-endian architectures.

(Needs some fixes or work-arounds.)  You can test with "guix build
azpainter --target=aarch64-linux-gnu" or such.

Also, some other problems.  From mlk_studio.c

int mFILEreadBE32(FILE *fp,void *buf)
{
	uint8_t v[4];

	if(fread(v, 1, 4, fp) < 4)
		return 1;
	else
	{
		*((uint32_t *)buf) = ((uint32_t)v[0] << 24) | (v[1] <<
16) | (v[2] << 8) | v[3];
		return 0;
	}
}

looks like a potential strict-aliasing violation to me, resulting in
undefined behaviour -- what if buf is a pointer to an array of, say,
doubles?  Also a potential alignment problem, though maybe it's only
called for sufficiently aligned 'buf'.  The strict-aliasing problem
can be worked around with -fno-strict-aliasing or maybe just -fno-ipa-
strict-aliasing , though I don't know if that's sufficient.

Greetings,
Maxime.

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  reply	other threads:[~2022-05-20 16:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-20 11:18 [bug#55541] [PATCH] gnu: Add azpainter Tobias Kortkamp
2022-05-20 16:00 ` Maxime Devos [this message]
2022-06-24 20:56 ` bug#55541: " Ludovic Courtès
2022-06-24 21:41   ` [bug#55541] " Maxime Devos

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