Re: [PATCH v3] Eclair: scan the last xen-syms linking pass on Arm

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2026-10-12 22:49, Dmytro Prokopchuk1 wrote:
> The hide pattern .xen-syms.[013] leaves pass 2 visible. On x86
> LAST_LINKING_PASS is 2, so that is the final link. On Arm
> LAST_LINKING_PASS is 3 and the final image is .xen-syms.3. Pass 2 is
> usually only a symlink, so Eclair saw no program link and reported 
> every
> translation unit as unreachable.
>
> During analysis preparation, read LAST_LINKING_PASS from the 
> architecture
> makefile and the pass numbers from the foreach list in
> xen/scripts/Makefile.link. Hide every pass except that one. An earlier
> pass that is a real link stays hidden. The generator runs from
> generate_ecl.sh, together with the other ECLAIR configuration scripts.
>
> Fixes: a401b5c9dc35 ("Eclair: re-enable scanning of the (almost) final 
> linking step")
> Signed-off-by: Dmytro Prokopchuk <dmytro_prokopchuk1@xxxxxxxx>
Acked-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>

Thanks for spotting and fixing this!

> ---
> Test CI pipeline: 
> https://gitlab.com/xen-project/people/dimaprkp4k/xen/-/pipelines/2940065908
> Changes in v3:
> - generate the hide pattern from generate_ecl.sh, which prepare.sh 
> already runs
> Link to v2:
> https://patchew.org/Xen/e73c282694e68083305d03219f983bf74a8bf494.1791392326.git.dmytro._5Fprokopchuk1@xxxxxxxx/
>
> Changes in v2:
> - update commit message
> - generate hide pattern before analysis
> - read LAST_LINKING_PASS from the arch Makefile and pass numbers from 
> the Makefile.link
> ---
>  .../eclair_analysis/ECLAIR/analysis.ecl       |  2 +-
>  .../ECLAIR/generate-xen-syms-passes.sh        | 20 +++++++++++++++++++
>  .../eclair_analysis/ECLAIR/generate_ecl.sh    |  3 +++
>  3 files changed, 24 insertions(+), 1 deletion(-)
>  create mode 100755 
> automation/eclair_analysis/ECLAIR/generate-xen-syms-passes.sh
> diff --git a/automation/eclair_analysis/ECLAIR/analysis.ecl 
> b/automation/eclair_analysis/ECLAIR/analysis.ecl
> index c6e1a7a95d..df1006bcaa 100644
> --- a/automation/eclair_analysis/ECLAIR/analysis.ecl
> +++ b/automation/eclair_analysis/ECLAIR/analysis.ecl
> @@ -37,7 +37,7 @@ their Standard Library equivalents."
>  -doc_begin="Do not analyze intermediate linking artifacts, as they do 
> not differ from their final
>  counterparts for the purposes of MISRA C static analysis."
>  -file_tag+={xen_efi_tmp, "^xen/\\.xen\\.efi\\.([01]|alt\\..*)$"}
> --file_tag+={xen_syms_tmp, "^xen/\\.xen-syms\\.[013]$"}
> +-eval_file=xen_syms_passes.ecl
>  -frames+={hide, "kind(program)&&target(xen_syms_tmp||xen_efi_tmp)"}
>  -doc_end
>
> diff --git 
> a/automation/eclair_analysis/ECLAIR/generate-xen-syms-passes.sh 
> b/automation/eclair_analysis/ECLAIR/generate-xen-syms-passes.sh
> new file mode 100755
> index 0000000000..e3795e8234
> --- /dev/null
> +++ b/automation/eclair_analysis/ECLAIR/generate-xen-syms-passes.sh
> @@ -0,0 +1,20 @@
> +#!/bin/bash
> +
> +# Hide every xen-syms linking pass except LAST_LINKING_PASS.
> +# The pass list is the foreach in xen/scripts/Makefile.link.
> +
> +set -e
> +
> +cd "$(dirname "$0")"
> +arch=$(echo "${XEN_TARGET_ARCH}" | sed -e 's/x86.*/x86/' -e 
> 's/arm.*/arm/')
> +last=$(sed -n 's/^LAST_LINKING_PASS *:= *\([0-9]\).*/\1/p' \
> +    "../../../xen/arch/${arch}/Makefile" | head -n 1)
> +passes=$(sed -n 's/.*foreach n,\([0-9 ]*\).*/\1/p' \
> +    ../../../xen/scripts/Makefile.link | head -n 1)
> +test -n "${last}"
> +test -n "${passes}"
> +hidden=$(printf '%s' "${passes}" | tr -d " ${last}")
> +
> +printf '%s\n' \
> +    "-file_tag+={xen_syms_tmp, 
> \"^xen/\\\\.xen-syms\\\\.[${hidden}]\$\"}" \
> +    >xen_syms_passes.ecl
> diff --git a/automation/eclair_analysis/ECLAIR/generate_ecl.sh 
> b/automation/eclair_analysis/ECLAIR/generate_ecl.sh
> index b955783904..b97fc55fd2 100755
> --- a/automation/eclair_analysis/ECLAIR/generate_ecl.sh
> +++ b/automation/eclair_analysis/ECLAIR/generate_ecl.sh
> @@ -20,3 +20,6 @@ 
> accepted_rst="${ECLAIR_PROJECT_ROOT}/docs/misra/rules.rst"
>  # Generate the list of linker-defined symbols (must be run after a Xen 
> build)
>  "${script_dir}/generate-linker-symbols.sh"
> +
> +# Hide every xen-syms linking pass except LAST_LINKING_PASS.
> +"${script_dir}/generate-xen-syms-passes.sh"
--
Nicola Vetrini, B.Sc.
Software Engineer
BUGSENG (https://bugseng.com)
LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253