On Tue, 22 Oct 2024 19:01:02 -0400 Andres Salomon <dilin...@queued.net> wrote:
Package: libclang-rt-19-dev
Version: 1:19.1.2-1
libclang-rt-19-dev currently isn't built for armhf, which is keeping
chromium (which recently switched away from clang 16) from migrating to
trixie. When I asked on IRC about why it wasn't built for armhf, I was
pointed to this commit, where libclang-rt-*dev stops being built for
32-bit architectures:
https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/commit/1a18aa1aa6e9fc698868fd22a99ea875f3efb20a
This was originally added to fix clang 18 FTBFS. The workaround has
since been removed from the 18 branch, but that hasn't been merged into
the 19 branch. I'd appreciate if someone could merge the removal into
the 19 branch so chromium's build-deps on armhf can be satisfied.
Please note: this is a bit more tricky that can be immediately seen
when considering backportin of llvm19 to bookworm. It is not a prob
just to (re-)enable this on trixie alone.
Namely, it needs a "t32 transition" when going from trixie to bookworm.
The problem is: current libllvm19 et al on trixie uses 64bit time_t
on 32bit platforms like armhf (I omit the i386 case here for brevity).
But when rebuilding this on bookworm, it'll use 32bit time_t.
Next, when one installs such libllvm19[-dev] with 32bit time_t on
bookworm system and builds something with it, it will use libllvm19
with 32bit time_t interface.
Now, when upgrading such system from bookworm to trixie, it will get
libllvm19 with 64bit time_t, which is incompatible with the programs
built on bookworm with 32bit time_t libllvm19.
So either current libllvm19 on trixie should have t64 suffix and this
suffix should be dropped when doing the backport; or when doing the
backport, all affected libs should have t32 suffix (and there's no
provision from dpkg to support ${t32:Provides}); or we just omit
the affected 32bit architectures such as armel.
It is definitely not enough to re-enable building stuff on 32bit
platforms to have the resulting package backportable.
Maybe it can be done by adding the t64 suffix to *current* libllvm19
et all on trixie *before* considering further actions, if we're to
think about back-porting it to bookworm.
Thanks,
/mjt
