Re: [PATCH v3 bpf] kbuild: fix dependencies for DEBUG_INFO_BTF

[Slava Bacherikov]

01.04.2020 17:20, Slava Bacherikov wrotes:
> Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
> enabled will produce invalid btf file, since gen_btf function in
> link-vmlinux.sh script doesn't handle *.dwo files.
> 
> Enabling DEBUG_INFO_REDUCED will also produce invalid btf file, and
> using GCC_PLUGIN_RANDSTRUCT with BTF makes no sense.
> 
> Signed-off-by: Slava Bacherikov <slava@xxxxxxxxxxxx>
> Reported-by: Jann Horn <jannh@xxxxxxxxxx>
> Reported-by: Liu Yiding <liuyd.fnst@xxxxxxxxxxxxxx>
> Acked-by: KP Singh <kpsingh@xxxxxxxxxx>
> Acked-by: Andrii Nakryiko <andriin@xxxxxx>
> Fixes: e83b9f55448a ("kbuild: add ability to generate BTF type info for vmlinux")
> ---
>  lib/Kconfig.debug | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index f61d834e02fe..b94227be2d62 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -222,7 +222,9 @@ config DEBUG_INFO_DWARF4
>  
>  config DEBUG_INFO_BTF
>  	bool "Generate BTF typeinfo"
> -	depends on DEBUG_INFO
> +	depends on DEBUG_INFO || COMPILE_TEST
I had to add this, since DEBUG_INFO which depends on:

	DEBUG_KERNEL && !COMPILE_TEST

would block DEBUG_INFO_BTF when COMPILE_TEST is turned on.

In that case allyesconfig will emit both:

CONFIG_DEBUG_INFO_BTF=y
CONFIG_GCC_PLUGIN_RANDSTRUCT=y



> +	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
> +	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
>  	help
>  	  Generate deduplicated BTF type information from DWARF debug info.
>  	  Turning this on expects presence of pahole tool, which will convert
>