[PATCH v2] lib/meson.build: allow build IGT with link time optimization

[Kamil Konieczny]

Hi Andrzej,
On 2025-01-09 at 17:26:30 +0100, Andrzej Hajda wrote:
> Some distributions use -flto gcc flag to build IGT. With this flag
> enabled variables declared with section attribute do not appear in
> correct section in .o files. Since iga64 assembly helper script relies
> on it we need to use -ffat-lto-objects in case of files containing
> iga64 assembly. According to documentation this option is effective
> only in case lto is in use, so it should not affect non-lto builds.
> 
> Closes: https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/issues/165
> Signed-off-by: Andrzej Hajda <andrzej.hajda at intel.com>

Reviewed-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>

> ---
> This patch 'fixes' building IGT with link-time-optimization. I am not
> sure it is or should be supported by IGT, but build scripts can be
> modified to allow it for testing.
> Grepping internet shows at least Gentoo and Arch Linux builds IGT with
> LTO, so I guess it is working for them.
> ---
> Changes in v2:
>  - added Closes tag
> - Link to v1: https://lore.kernel.org/r/20241216-fix-lto-v1-1-1280b17dc70f@intel.com
> ---
>  lib/meson.build | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/meson.build b/lib/meson.build
> index 1704ed1e1c17..9fffdd3c6218 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -240,7 +240,7 @@ foreach f: lib_sources
>  	    '-DIGT_DATADIR="@0@"'.format(join_paths(prefix, datadir)),
>  	    '-DIGT_SRCDIR="@0@"'.format(srcdir),
>  	    '-DIGT_LOG_DOMAIN="@0@"'.format(f.split('.')[0]),
> -	])
> +	] + (iga64_assembly_sources.contains(f) ? [ '-ffat-lto-objects' ] : []))
>  
>      lib_intermediates += lib
>      if iga64_assembly_sources.contains(f)
> 
> ---
> base-commit: ee7a3ac616f55f6ed1b959ff951237099bda86d8
> change-id: 20241216-fix-lto-8d3bc1488c6a
> 
> Best regards,
> -- 
> Andrzej Hajda <andrzej.hajda at intel.com>
>