Re: [Buildroot] [PATCH] package/libpcap: fix m68k-cf compile issue

From: Thomas Petazzoni via buildroot <buildroot@buildroot.org>
To: Waldemar Brodkorb <wbx@openadk.org>
Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>,
	buildroot@buildroot.org
Subject: Re: [Buildroot] [PATCH] package/libpcap: fix m68k-cf compile issue
Date: Wed, 14 Aug 2024 19:57:17 +0200	[thread overview]
Message-ID: <20240814195717.43707f3f@windsurf> (raw)
In-Reply-To: <ZrysgCNIRtUzTjbG@waldemar-brodkorb.de>

Hello Waldemar,

On Wed, 14 Aug 2024 15:09:20 +0200
Waldemar Brodkorb <wbx@openadk.org> wrote:

> Compilation with -Os triggers this assembler problem.
> 
> Fixes:
>  - http://autobuild.buildroot.net/results/db5/db58215fb3c7f30b6c0f0764a84271010346edfb
> 
> Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>

[...]

> diff --git a/package/libpcap/libpcap.mk b/package/libpcap/libpcap.mk
> index a4523f2218..257ec77e08 100644
> --- a/package/libpcap/libpcap.mk
> +++ b/package/libpcap/libpcap.mk
> @@ -57,5 +57,11 @@ ifeq ($(BR2_microblaze)$(BR2_sparc)$(BR2_sparc64),y)
>  LIBPCAP_CFLAGS += -fPIC
>  endif
>  
> +# Enable default optimizations to not run into "Error: value -602 out of range"
> +# assembler issues. -Os triggers the issue.
> +ifeq ($(BR2_m68k_cf),y)
> +LIBPCAP_CFLAGS += -O2
> +endif

Thanks for the patch, but this is not how we handle gcc or binutils
bugs. Instead, we report the bug upstream, and once the bug is
reported, we add a BR2_TOOLCHAIN_HAS_GCC_BUG_12345 or
BR2_TOOLCHAIN_HAS_BINUTILS_BUG_12345 (depending on which component is
affected), this option is enabled on a per-architecture basis, and
sometimes per-gcc version basis, and then the workaround in the package
is made conditional on this option. This allows us to track to which
GCC/binutils bug a workaround is related, and from to time check if the
issue has been fixed in newer versions of gcc/binutils.

See toolchain/Config.in for a lot of examples. Giulio in Cc can also
help with this, he is our resident expert in BR2_TOOLCHAIN_HAS_xyz_BUG
workarounds :-)

Your bug seems somewhat similar to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104028,
for which we already have BR2_TOOLCHAIN_HAS_GCC_BUG_104028 in
Buildroot. Not sure it is exactly the same bug.

Best regards,

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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