Fail to build llvm-toolchain-11 1:11.0.1-2 on Debian Bullseye using pbuilder

[Nykau]

Hi,

I fail to build llvm-toolchain-11_11.0.1-2 on a Debian Bullseye machine
using pbuilder. The long build eventually fails with the trace:

nykau at bullseye:~/tmp/libllvm11$ ls
control.patch  llvm-toolchain-11-11.0.1  llvm-toolchain-11_11.0.1-2.debian.tar.xz  llvm-toolchain-11_11.0.1-2.dsc  llvm-toolchain-11_11.0.1.orig.tar.xz
nykau at bullseye:~/tmp/libllvm11$ sudo pbuilder build --configfile ~/.pbuilderrc llvm-toolchain-11_11.0.1-2.dsc
....
LOTS of build traces, no suspicious output
....
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/llvm-11-tools/usr/lib/llvm-11/bin/not debian/llvm-11-tools/usr/lib/llvm-11/bin/FileCheck debian/llvm-11-tools/usr/lib/llvm-11/bin/yaml-bench were not linked against libdl.so.2 (they use none of the library's symbols)
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/llvm-11-tools/usr/lib/llvm-11/bin/not debian/llvm-11-tools/usr/lib/llvm-11/bin/FileCheck debian/llvm-11-tools/usr/lib/llvm-11/bin/yaml-bench were not linked against libz3.so.4 (they use none of the library's symbols)
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/llvm-11-tools/usr/lib/llvm-11/bin/not debian/llvm-11-tools/usr/lib/llvm-11/bin/FileCheck debian/llvm-11-tools/usr/lib/llvm-11/bin/yaml-bench were not linked against librt.so.1 (they use none of the library's symbols)
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/llvm-11-tools/usr/lib/llvm-11/bin/not debian/llvm-11-tools/usr/lib/llvm-11/bin/FileCheck debian/llvm-11-tools/usr/lib/llvm-11/bin/yaml-bench were not linked against libz.so.1 (they use none of the library's symbols)
dpkg-shlibdeps: warning: debian/libc++1-11/usr/lib/llvm-11/lib/libc++.so.1.0 contains an unresolvable reference to symbol _Unwind_Resume: it's probably a plugin
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/libc++1-11/usr/lib/llvm-11/lib/libc++.so.1.0 was not linked against libm.so.6 (it uses none of the library's symbols)
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/libc++1-11/usr/lib/llvm-11/lib/libc++.so.1.0 was not linked against librt.so.1 (it uses none of the library's symbols)
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/libc++1-11/usr/lib/llvm-11/lib/libc++.so.1.0 was not linked against libatomic.so.1 (it uses none of the library's symbols)
dpkg-shlibdeps: error: no dependency information found for /build/llvm-toolchain-11-11.0.1/debian/tmp/usr/lib/llvm-11/lib/libclang-cpp.so.11 (used by debian/clang-11/usr/lib/llvm-11/bin/clang)
Hint: check if the library actually comes from a package.
dh_shlibdeps: error: dpkg-shlibdeps -Tdebian/clang-11.substvars -tudeb -l/build/llvm-toolchain-11-11.0.1/debian/tmp//usr/lib/llvm-11/lib/ debian/clang-11/usr/lib/llvm-11/bin/clang returned exit code 255
dpkg-shlibdeps: warning: debian/libc++abi1-11/usr/lib/llvm-11/lib/libc++abi.so.1.0 contains an unresolvable reference to symbol _Unwind_RaiseException: it's probably a plugin
dpkg-shlibdeps: warning: 7 other similar warnings have been skipped (use -v to see them all)
dpkg-shlibdeps: error: no dependency information found for /build/llvm-toolchain-11-11.0.1/debian/tmp/usr/lib/llvm-11/lib/libLLVM-11.so.1 (used by debian/lld-11/usr/lib/llvm-11/bin/lld)
Hint: check if the library actually comes from a package.
dh_shlibdeps: error: dpkg-shlibdeps -Tdebian/lld-11.substvars -tudeb -l/build/llvm-toolchain-11-11.0.1/debian/tmp//usr/lib/llvm-11/lib/ debian/lld-11/usr/lib/llvm-11/bin/lld returned exit code 255
dpkg-shlibdeps: error: no dependency information found for /build/llvm-toolchain-11-11.0.1/debian/tmp/usr/lib/llvm-11/lib/libLLVM-11.so.1 (used by debian/libclang-cpp11/usr/lib/llvm-11/lib/libclang-cpp.so.11)
Hint: check if the library actually comes from a package.
dh_shlibdeps: error: dpkg-shlibdeps -Tdebian/libclang-cpp11.substvars -tudeb -l/build/llvm-toolchain-11-11.0.1/debian/tmp//usr/lib/llvm-11/lib/ debian/libclang-cpp11/usr/lib/llvm-11/lib/libclang-cpp.so.11 returned exit code 255
dh_shlibdeps: error: Aborting due to earlier error
make[1]: *** [debian/rules:731: override_dh_shlibdeps] Error 2
make[1]: Leaving directory '/build/llvm-toolchain-11-11.0.1'
make: *** [debian/rules:299: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2
I: copying local configuration
E: Failed autobuilding of package
I: unmounting dev/ptmx filesystem
I: unmounting dev/pts filesystem
I: unmounting dev/shm filesystem
I: unmounting proc filesystem
I: unmounting sys filesystem
I: cleaning the build env
I: removing directory /dev/shm/pbuilder/build/1201501 and its subdirectories
nykau at bullseye:~/tmp/libllvm11$

(Full output available on request)

Here is the content of ~/.pbuilderrc

AUTO_DEBSIGN=${AUTO_DEBSIGN:-no}
HOME=/home/AD.HOUSEALPACA.COM/nykau
#BASEDIR=${HOME}/.local/var/cache/pbuilder
BASEDIR=/dev/shm/pbuilder
#BASEDIR=/media/host/home/nicmel/tmp/pbuilder
APTCACHE=${BASEDIR}/aptcache
HOOKDIR=${BASEDIR}/hooks
APTCACHEHARDLINK=no
BUILDPLACE=${BASEDIR}/build
BUILDPLACE=/dev/shm/pbuilder/build
#BUILDRESULT=${BASEDIR}/result
#CCACHEDIR=${BASEDIR}/ccache
BASEPATH=${BASEDIR}/base.cow
APTCONFDIR=/etc/apt
DISTRIBUTION=bullseye

There is nothing in /etc/apt out of the ordinary, except a steam repository
cat /etc/apt/sources.list.d/steam.list
deb [arch=amd64,i386] https://repo.steampowered.com/steam/ stable steam
deb-src [arch=amd64,i386] https://repo.steampowered.com/steam/ stable steam

I don't know what happens that prevent pbuilder from building llvm-
toolchain-11 correctly. I tried compiling it without pbuilder, using
dpkg-buildpackage (fakeroot dpkg-buildpackage -us -uc -nc -j1) but I
eventually get the same result; with many failure in between.

I believe pbuilder only reads the .dsc file, i.e., it ignores the
content of directory llvm-toolchain-11-11.0.1 and other .tar.xz files
next to it, doesn't it? If it does use these other files, it may be
worth to know that I modified llvm-toolchain-11-11.0.1/debian/control
so that all packages generated as udebs instead of debs, but I did not
change anything else.

Thanks for your help,

Nicolas