Re: [PATCH 2/2] add example how to use derived sbuild chroots

[Henning Schild <henning.schild@siemens.com>]

Am Thu, 13 Apr 2023 07:00:26 +0000
schrieb "'Felix Moessbauer' via isar-users"
<isar-users@googlegroups.com>:

> This patch extends the samefile recipe to use a derived sbuild chroot
> to compile the tool using clang instead of gcc. While there are
> easier ways to achive this goal, it is still valuable to demonstrate
> how to use the infrastructure.
> 
> Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
> ---
>  meta-isar/recipes-app/samefile/samefile_2.14.bb       |  8 ++++++++
>  .../sbuild-chroot/sbuild-chroot-target-clang.bb       | 11
> +++++++++++ 2 files changed, 19 insertions(+)
>  create mode 100644
> meta-isar/recipes-devtools/sbuild-chroot/sbuild-chroot-target-clang.bb
> 
> diff --git a/meta-isar/recipes-app/samefile/samefile_2.14.bb
> b/meta-isar/recipes-app/samefile/samefile_2.14.bb index
> c53c9445..989e1983 100644 ---
> a/meta-isar/recipes-app/samefile/samefile_2.14.bb +++
> b/meta-isar/recipes-app/samefile/samefile_2.14.bb @@ -5,6 +5,9 @@
>  
>  inherit dpkg
>  
> +# for demo reasons, we compile with clang if not cross-compiling
> +SBUILD_FLAVOR = "${@ 'clang' if d.getVar('ISAR_CROSS_COMPILE') !=
> '1' else '' }" +
>  DEBIAN_DEPENDS = "\${misc:Depends}"
>  DESCRIPTION = "utility that finds files with identical contents"
>  
> @@ -42,4 +45,9 @@ EOF
>  
>      # We can also customize afterwards, in this case change the
> package section. sed -i -e 's/Section: misc/Section: utils/g'
> ${S}/debian/control +
> +    # use clang to compile (no cross support yet)
> +    if [ "${SBUILD_FLAVOR}" = "clang" ]; then
> +        sed -i -e 's/\(#\!.*\)/\1\nexport CC=clang/g'
> ${S}/debian/rules

This is going pretty far to demo the case. Even so far that
Build-Depends might be wrong and only satisfied with the magic.

You do not demo speed-ups by preinstalled build-deps, you demo hackery.

> +    fi
>  }
> diff --git
> a/meta-isar/recipes-devtools/sbuild-chroot/sbuild-chroot-target-clang.bb
> b/meta-isar/recipes-devtools/sbuild-chroot/sbuild-chroot-target-clang.bb
> new file mode 100644 index 00000000..3df16368 --- /dev/null
> +++
> b/meta-isar/recipes-devtools/sbuild-chroot/sbuild-chroot-target-clang.bb
> @@ -0,0 +1,11 @@ +# Root filesystem for packages building with clang
> +#
> +# This software is a part of ISAR.
> +# Copyright (C) 2023 Siemens AG
> +
> +DESCRIPTION = "Isar sbuild/schroot filesystem for target (clang
> variant)" +
> +require recipes-devtools/sbuild-chroot/sbuild-chroot-target.bb
> +
> +SBUILD_FLAVOR = "clang"
> +SBUILD_CHROOT_PREINSTALL_COMMON += "clang"

A bit unfortunate that the only one package name was also chosen as the
flavor name.

Maybe add some comments here, which one is a "name" and which one is a
"package list", or try to pick different strings as name.

Does that package benefit in any way from clang being preinstalled? I
guess only artificially because you patched in the CC=clang ...

Henning