On profiles like default/linux/amd64/17.1/systemd/clang/merged-usr (exp) `glibc`+`clang` provide incomplete set of libraries to be able to link simple executables using printf(). Minimal reproducer: good: # echo -e '#include <stdio.h>\nint main() { printf("printf_address = %p\\n", &printf); }' | clang -x c - -o a && ./a printf_address = 0x7eff78a06420 bad: # echo -e '#include <stdio.h>\nint main() { printf("printf_address = %p\\n", &printf); }' | clang -x c - -o a -static && ./a ld.lld: error: undefined symbol: __unordtf2 >>> referenced by printf_fphex.o:(__printf_fphex) in archive /usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../lib64/libc.a ... I think this happens because `glibc` is built by `gcc`. `gcc` assumes presence of TF (long double) types and provides external helpers via `libgcc.a`. Looks like `clang` does not provide a substitute in any form in it's runtime. So far I'm stubbing those out as https://github.com/trofi/nix-guix-gentoo/blob/master/sys-apps/busybox-nix-sandbox-shell/files/libgcc-TF-stubs.c. But I think the toolchain should provide something that just works. Be it `glibc` without unsatisfiable symbols, or a `clang` driver` without enough runtime libraries or whatever works. Example of ::gentoo packages that suffers the same is busybox: # USE='-pam static' emerge -v1 busybox Output of: clang -O2 -pipe -fdiagnostics-show-option -frecord-gcc-switches -fno-strict-aliasing -Wall -Wshadow -Wwrite-strings -Wundef -Wstrict-prototypes -Wunused -Wunused-parameter -Wunused-function -Wunused-value -Wmissing-prototypes -Wmissing-declarations -Wno-format-security -Wdeclaration-after-statement -Wold-style-definition -fno-builtin-strlen -ffunction-sections -fdata-sections -funsigned-char -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-builtin-printf -Wno-string-plus-int -Wno-constant-logical-operand -static -Wl,-O1 -Wl,--as-needed -fuse-ld=lld -rtlib=compiler-rt -unwindlib=libunwind -Wl,--as-needed -Wl,--hash-style=gnu -o busybox_unstripped -Wl,--start-group applets/built-in.o archival/lib.a archival/libarchive/lib.a console-tools/lib.a coreutils/lib.a coreutils/libcoreutils/lib.a debianutils/lib.a klibc-utils/lib.a e2fsprogs/lib.a editors/lib.a findutils/lib.a init/lib.a libbb/lib.a libpwdgrp/lib.a loginutils/lib.a mailutils/lib.a miscutils/lib.a modutils/lib.a networking/lib.a networking/libiproute/lib.a networking/udhcp/lib.a printutils/lib.a procps/lib.a runit/lib.a selinux/lib.a shell/lib.a sysklogd/lib.a util-linux/lib.a util-linux/volume_id/lib.a archival/built-in.o archival/libarchive/built-in.o console-tools/built-in.o coreutils/built-in.o coreutils/libcoreutils/built-in.o debianutils/built-in.o klibc-utils/built-in.o e2fsprogs/built-in.o editors/built-in.o findutils/built-in.o init/built-in.o libbb/built-in.o libpwdgrp/built-in.o loginutils/built-in.o mailutils/built-in.o miscutils/built-in.o modutils/built-in.o networking/built-in.o networking/libiproute/built-in.o networking/udhcp/built-in.o printutils/built-in.o procps/built-in.o runit/built-in.o selinux/built-in.o shell/built-in.o sysklogd/built-in.o util-linux/built-in.o util-linux/volume_id/built-in.o -Wl,--end-group -Wl,--start-group -lcrypt -lm -lresolv -lrt -Wl,--end-group ========== ld.lld: error: undefined symbol: __multf3 >>> referenced by strtof128_l.o:(round_and_return) in archive /usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../lib64/libc.a
# emerge --info Portage 3.0.45.2 (python 3.10.10-final-0, default/linux/amd64/17.1/systemd/clang/merged-usr, gcc-12, glibc-2.36-r7, 6.2.1 x86_64) ================================================================= System uname: Linux-6.2.1-x86_64-AMD_Ryzen_9_5950X_16-Core_Processor-with-glibc2.36 KiB Mem: 131859788 total, 22959376 free KiB Swap: 197789180 total, 197789180 free Timestamp of repository gentoo: Sat, 04 Mar 2023 08:30:01 +0000 Head commit of repository gentoo: c260eeeeb3aa68a135e099dbc3e60f8788016c3e sh bash 5.2_p15-r2 ld GNU ld (Gentoo 2.40 p2) 2.40.0 app-misc/pax-utils: 1.3.7::gentoo app-shells/bash: 5.2_p15-r2::gentoo dev-lang/perl: 5.36.0-r2::gentoo dev-lang/python: 3.10.10_p2::gentoo, 3.11.2_p1::gentoo dev-lang/rust: 1.67.0::gentoo dev-util/cmake: 3.25.2::gentoo dev-util/meson: 1.0.0::gentoo sys-apps/baselayout: 2.13-r1::gentoo sys-apps/sandbox: 2.30-r1::gentoo sys-apps/systemd: 253.1::gentoo sys-devel/autoconf: 2.71-r5::gentoo sys-devel/automake: 1.16.5::gentoo sys-devel/binutils: 2.40-r2::gentoo sys-devel/binutils-config: 5.5::gentoo sys-devel/clang: 15.0.7-r1::gentoo sys-devel/gcc: 12.2.1_p20230121-r1::gentoo sys-devel/gcc-config: 2.10::gentoo sys-devel/libtool: 2.4.7-r1::gentoo sys-devel/lld: 15.0.7::gentoo sys-devel/llvm: 15.0.7::gentoo sys-devel/make: 4.4.1::gentoo sys-kernel/linux-headers: 6.2::gentoo (virtual/os-headers) sys-libs/glibc: 2.36-r7::gentoo Repositories: gentoo location: /bound/portage sync-type: rsync sync-uri: rsync://rsync.gentoo.org/gentoo-portage priority: -1000 volatile: True sync-rsync-extra-opts: sync-rsync-verify-max-age: 24 sync-rsync-verify-jobs: 1 sync-rsync-verify-metamanifest: yes slyfox location: /bound/slyfox-gentoo masters: gentoo priority: 0 volatile: True nix-guix location: /bound/nix-guix-gentoo masters: gentoo priority: 1 volatile: True ACCEPT_KEYWORDS="amd64 ~amd64" ACCEPT_LICENSE="@FREE" ADDR2LINE="llvm-addr2line" AR="llvm-ar" AS="clang -c" CBUILD="x86_64-pc-linux-gnu" CC="clang" CFLAGS="-O2 -pipe -fdiagnostics-show-option -frecord-gcc-switches" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/gconf /etc/gentoo-release /etc/sandbox.d" CPP="clang-cpp" CXX="clang++" CXXFLAGS="-O2 -pipe" DISTDIR="/bound/distfiles" ENV_UNSET="CARGO_HOME DBUS_SESSION_BUS_ADDRESS DISPLAY GDK_PIXBUF_MODULE_FILE GOBIN GOPATH PERL5LIB PERL5OPT PERLPREFIX PERL_CORE PERL_MB_OPT PERL_MM_OPT XAUTHORITY XDG_CACHE_HOME XDG_CONFIG_HOME XDG_DATA_HOME XDG_RUNTIME_DIR XDG_STATE_HOME" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs binpkg-multi-instance buildpkg-live config-protect-if-modified distlocks ebuild-locks fail-clean fixlafiles ipc-sandbox merge-sync multilib-strict network-sandbox news parallel-fetch pid-sandbox preserve-libs protect-owned qa-unresolved-soname-deps sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr" FFLAGS="-O2 -pipe" GENTOO_MIRRORS="http://distfiles.gentoo.org" LANG="C.UTF8" LD="ld.lld" LDFLAGS="-Wl,-O1 -Wl,--as-needed -fuse-ld=lld -rtlib=compiler-rt -unwindlib=libunwind -Wl,--as-needed -Wl,--hash-style=gnu" LEX="flex" MAKEOPTS="-j17 -l17" NM="llvm-nm" OBJCOPY="llvm-objcopy" OBJDUMP="llvm-objdump" PKGDIR="/var/cache/binpkgs" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --exclude=/.git" PORTAGE_TMPDIR="/dev/shm" RANLIB="llvm-ranlib" READELF="llvm-readelf" SHELL="/bin/bash" STRINGS="llvm-strings" STRIP="llvm-strip" USE="acl amd64 bzip2 clang cli crypt dri fortran gdbm iconv ipv6 libglvnd libtirpc llvm-libunwind multilib ncurses nls nptl openmp pam pcre readline seccomp ssl systemd test-rust udev unicode xattr zlib" ABI_X86="64" ADA_TARGET="gnat_2021" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="karbon sheets words" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="mmx mmxext sse sse2" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock greis isync itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="libinput" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LUA_SINGLE_TARGET="lua5-1" LUA_TARGETS="lua5-1" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php7-4 php8-0" POSTGRES_TARGETS="postgres12 postgres13" PYTHON_SINGLE_TARGET="python3_10" PYTHON_TARGETS="python3_10" RUBY_TARGETS="ruby27 ruby30" USERLAND="GNU" VIDEO_CARDS="amdgpu fbdev intel nouveau radeon radeonsi vesa dummy v4l" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq proto steal rawnat logmark ipmark dhcpmac delude chaos account" Unset: ARFLAGS, ASFLAGS, CCLD, CONFIG_SHELL, CPPFLAGS, CTARGET, CXXFILT, ELFEDIT, EMERGE_DEFAULT_OPTS, EXTRA_ECONF, F77FLAGS, FC, GCOV, GPROF, INSTALL_MASK, LC_ALL, LFLAGS, LIBTOOL, LINGUAS, MAKE, MAKEFLAGS, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, RUSTFLAGS, SIZE, YACC, YFLAGS
Thanks, this is a good spot. catcream mentioned this last night but I didn't have a chance to look into it yet. Another thing we can explore is llvm's libgcc set of shims which is quite new.
* https://discourse.llvm.org/t/compiler-rt-with-soft-float-support/4936 * https://discourse.llvm.org/t/static-linking-with-compiler-rt-and-libc-2-31-does-not-work/4960 * https://reviews.llvm.org/D53608
