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

Slava Bacherikov
2020-04-01T14:38:10Z

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@bacher09.org>
> Reported-by: Jann Horn <jannh@google.com>
> Reported-by: Liu Yiding <liuyd.fnst@cn.fujitsu.com>
> Acked-by: KP Singh <kpsingh@google.com>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
> 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
>