Re: [PATCH 3/3] btf: require pahole 1.21+ for DEBUG_INFO_BTF with default DWARF version

[Nathan Chancellor]

On Wed, Sep 11, 2024 at 08:03:58PM +0900, Masahiro Yamada wrote:
> As described in commit 42d9b379e3e1 ("lib/Kconfig.debug: Allow BTF +
> DWARF5 with pahole 1.21+"), the combination of CONFIG_DEBUG_INFO_BTF
> and CONFIG_DEBUG_INFO_DWARF5 requires pahole 1.21+.
> 
> GCC 11+ and Clang 14+ default to DWARF 5 when the -g flag is passed.
> For the same reason, the combination of CONFIG_DEBUG_INFO_BTF and
> CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT is also likely to require
> pahole 1.21+. (At least, it is uncertain whether the requirement is
> pahole 1.16+ or 1.21+.)
> 
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>

Indeed, I think this is a safer, longterm dependency, until we bump the
minimum versions to the ones listed in the commit message, unless there
is DWARF6 by that point :)

Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>

> ---
> 
>  lib/Kconfig.debug | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index eff408a88dfd..011a7abc68a8 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -380,7 +380,7 @@ config DEBUG_INFO_BTF
>  	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
>  	depends on BPF_SYSCALL
>  	depends on PAHOLE_VERSION >= 116
> -	depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
> +	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
>  	# pahole uses elfutils, which does not have support for Hexagon relocations
>  	depends on !HEXAGON
>  	help
> -- 
> 2.43.0
>