Re: [PATCH 5.10] scripts/lld-version.sh: Rewrite based on upstream ld-version.sh

Nick Desaulniers
2021-11-15T17:50:14Z

On Mon, Nov 15, 2021 at 8:46 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> This patch is for linux-5.10.y only.
>
> When scripts/lld-version.sh was initially written, it did not account
> for the LLD_VENDOR cmake flag, which changes the output of ld.lld's
> --version flag slightly.
>
> Without LLD_VENDOR:
>
> $ ld.lld --version
> LLD 14.0.0 (compatible with GNU linkers)
>
> With LLD_VENDOR:
>
> $ ld.lld --version
> Debian LLD 14.0.0 (compatible with GNU linkers)
>
> As a result, CONFIG_LLD_VERSION is messed up and configuration values
> that are dependent on it cannot be selected:
>
> scripts/lld-version.sh: 20: printf: LLD: expected numeric value
> scripts/lld-version.sh: 20: printf: LLD: expected numeric value
> scripts/lld-version.sh: 20: printf: LLD: expected numeric value
> init/Kconfig:52:warning: 'LLD_VERSION': number is invalid
> .config:11:warning: symbol value '00000' invalid for LLD_VERSION
> .config:8800:warning: override: CPU_BIG_ENDIAN changes choice state
>
> This was fixed upstream by commit 1f09af062556 ("kbuild: Fix
> ld-version.sh script if LLD was built with LLD_VENDOR") in 5.12 but that
> was done to ld-version.sh after it was massively rewritten in
> commit 02aff8592204 ("kbuild: check the minimum linker version in
> Kconfig").
>
> To avoid bringing in that change plus its prerequisites and fixes, just
> modify lld-version.sh to make it similar to the upstream ld-version.sh,
> which handles ld.lld with or without LLD_VENDOR and ld.bfd without any
> errors.
>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Thanks for the fix.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>
> Our CI caught this error with newer versions of Debian's ld.lld, which
> added LLD_VENDOR it seems:
>
> https://github.com/ClangBuiltLinux/continuous-integration2/runs/4206343929?check_suite_focus=true
>
> A similar change was done by me for Android, where it has seen no
> issues:
>
> https://android-review.googlesource.com/c/kernel/common/+/1744324
>
> I believe this is a safer change than backporting the fixes from
> upstream but if you guys feel otherwise, I can do so. This is only
> needed in 5.10 as CONFIG_LLD_VERSION does not exist in 5.4 and it was
> fixed in 5.12 upstream.
>
> scripts/lld-version.sh | 35 ++++++++++++++++++++++++++---------
> 1 file changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/scripts/lld-version.sh b/scripts/lld-version.sh
> index d70edb4d8a4f..f1eeee450a23 100755
> --- a/scripts/lld-version.sh
> +++ b/scripts/lld-version.sh
> @@ -6,15 +6,32 @@
> # Print the linker version of `ld.lld' in a 5 or 6-digit form
> # such as `100001' for ld.lld 10.0.1 etc.
>
> -linker_string="$($* --version)"
> +set -e
>
> -if ! ( echo $linker_string | grep -q LLD ); then
> +# Convert the version string x.y.z to a canonical 5 or 6-digit form.
> +get_canonical_version()
> +{
> + IFS=.
> + set -- $1
> +
> + # If the 2nd or 3rd field is missing, fill it with a zero.
> + echo $((10000 * $1 + 100 * ${2:-0} + ${3:-0}))
> +}
> +
> +# Get the first line of the --version output.
> +IFS='
> +'
> +set -- $(LC_ALL=C "$@" --version)
> +
> +# Split the line on spaces.
> +IFS=' '
> +set -- $1
> +
> +while [ $# -gt 1 -a "$1" != "LLD" ]; do
> + shift
> +done
> +if [ "$1" = LLD ]; then
> + echo $(get_canonical_version ${2%-*})
> +else
> echo 0
> - exit 1
> fi
> -
> -VERSION=$(echo $linker_string | cut -d ' ' -f 2)
> -MAJOR=$(echo $VERSION | cut -d . -f 1)
> -MINOR=$(echo $VERSION | cut -d . -f 2)
> -PATCHLEVEL=$(echo $VERSION | cut -d . -f 3)
> -printf "%d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL
>
> base-commit: bd816c278316f20a5575debc64dde4422229a880
> --
> 2.34.0.rc0
>

--
Thanks,
~Nick Desaulniers