Errors compiling `libc` using rust 1.73.0 on `riscv64/ubuntu:focal` docker image - works with 1.72.1

[emlowe]

h/w device: Starfive VisionFive2 SoC board
docker image : riscv64/ubuntu:focal - (LTS Ubuntu 20)
Docker version 20.10.21

The issue also appears using QEMU.
The issue also appears using rust 1.75.0-nightly
The issue also appears compiling libc 0.2.148

Note - the issue DOES NOT appear

• using image riscv64/ubuntu:jammy - (LTS Ubuntu 22)
• using rust 1.72.1

Target = stable-riscv64gc-unknown-linux-gnu

empty project with libc dependency:

[package]
name = "test_crate"
version = "0.1.0"
edition = "2021"

[dependencies]
libc = "0.2.149"

root@000f3594006f:/ws# cargo clean && cargo build --verbose --verbose
   Compiling libc v0.2.149
     Running `CARGO=/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/bin/cargo CARGO_CRATE_NAME=build_script_build CARGO_MANIFEST_DIR=/root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libc-0.2.149 CARGO_PKG_AUTHORS='The Rust Project Developers' CARGO_PKG_DESCRIPTION='Raw FFI bindings to platform libraries like libc.
' CARGO_PKG_HOMEPAGE='https://github.com/rust-lang/libc' CARGO_PKG_LICENSE='MIT OR Apache-2.0' CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=libc CARGO_PKG_README=README.md CARGO_PKG_REPOSITORY='https://github.com/rust-lang/libc' CARGO_PKG_RUST_VERSION='' CARGO_PKG_VERSION=0.2.149 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=2 CARGO_PKG_VERSION_PATCH=149 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/ws/target/debug/deps:/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib:/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib' /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/bin/rustc --crate-name build_script_build /root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libc-0.2.149/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=204 --crate-type bin --emit=dep-info,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="std"' -C metadata=96e5e627a3abf8c8 -C extra-filename=-96e5e627a3abf8c8 --out-dir /ws/target/debug/build/libc-96e5e627a3abf8c8 -L dependency=/ws/target/debug/deps --cap-lints warn`
error: linking with `cc` failed: exit status: 1
  |
  = note: LC_ALL="C" PATH="/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/bin:/root/.cargo/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" VSLANG="1033" "cc" "/tmp/rustcCVctF1/symbols.o" "/ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.0.rcgu.o" "/ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.1.rcgu.o" "/ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.2.rcgu.o" "/ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.3.rcgu.o" "/ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.2gwogyquwaava3wi.rcgu.o" "-Wl,--as-needed" "-L" "/ws/target/debug/deps" "-L" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libstd-7c20a79be40626d5.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libpanic_unwind-0828025c99efa306.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libobject-cad77585ea5b2597.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libmemchr-819221be8f9a39ca.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libaddr2line-27305f678c78b7e8.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libgimli-d6dc5edd95c10e8b.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_demangle-0d40f94f5bf49047.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libstd_detect-400d9ad6f69566ef.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libhashbrown-efe127239291790f.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_std_workspace_alloc-b2b1393aaa45cbdc.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libminiz_oxide-3f8d7ae12780bb8a.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libadler-9fd99aca5a91830a.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libunwind-130742698a3dada1.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcfg_if-61c4490aa3cd5617.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/liblibc-11b24d104e4a6819.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/liballoc-edf623dacc1b8376.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_std_workspace_core-f7351a9898cc3f1f.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcore-8c347cbe3d348ef5.rlib" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcompiler_builtins-83534430d5ebaab4.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib" "-o" "/ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs"
  = note: /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.1.rcgu.o
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.2.rcgu.o
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.build_script_build.78bae1900acaa159-cgu.3.rcgu.o
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /ws/target/debug/build/libc-96e5e627a3abf8c8/build_script_build-96e5e627a3abf8c8.2gwogyquwaava3wi.rcgu.o
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libstd-7c20a79be40626d5.rlib(std-7c20a79be40626d5.std.bf3dc212422480e-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libpanic_unwind-0828025c99efa306.rlib(panic_unwind-0828025c99efa306.panic_unwind.7653168454a35d11-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libobject-cad77585ea5b2597.rlib(object-cad77585ea5b2597.object.df09169ba80752fc-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libmemchr-819221be8f9a39ca.rlib(memchr-819221be8f9a39ca.memchr.9319e8ba93f7c543-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libaddr2line-27305f678c78b7e8.rlib(addr2line-27305f678c78b7e8.addr2line.1dbb935f6e696ff5-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libgimli-d6dc5edd95c10e8b.rlib(gimli-d6dc5edd95c10e8b.gimli.c09175a2afb04107-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_demangle-0d40f94f5bf49047.rlib(rustc_demangle-0d40f94f5bf49047.rustc_demangle.63400a85a5bf63f4-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libminiz_oxide-3f8d7ae12780bb8a.rlib(miniz_oxide-3f8d7ae12780bb8a.miniz_oxide.9d43bb9f04dbfc00-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libadler-9fd99aca5a91830a.rlib(adler-9fd99aca5a91830a.adler.84d4be1594b06e2c-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/liblibc-11b24d104e4a6819.rlib(libc-11b24d104e4a6819.libc.3c82556467890d0-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/liballoc-edf623dacc1b8376.rlib(alloc-edf623dacc1b8376.alloc.d475226557833bf6-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcore-8c347cbe3d348ef5.rlib(core-8c347cbe3d348ef5.core.2983b1ded1f05c41-cgu.0.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcompiler_builtins-83534430d5ebaab4.rlib(compiler_builtins-83534430d5ebaab4.compiler_builtins.d269826ba1c73e2b-cgu.044.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcompiler_builtins-83534430d5ebaab4.rlib(compiler_builtins-83534430d5ebaab4.compiler_builtins.d269826ba1c73e2b-cgu.090.rcgu.o)
          /usr/bin/ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0: unsupported ISA subset `z'
          /usr/bin/ld: failed to merge target specific data of file /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcompiler_builtins-83534430d5ebaab4.rlib(compiler_builtins-83534430d5ebaab4.compiler_builtins.d269826ba1c73e2b-cgu.006.rcgu.o)
          collect2: error: ld returned 1 exit status
          

error: could not compile `libc` (build script) due to previous error

Caused by:
  process didn't exit successfully: `CARGO=/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/bin/cargo CARGO_CRATE_NAME=build_script_build CARGO_MANIFEST_DIR=/root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libc-0.2.149 CARGO_PKG_AUTHORS='The Rust Project Developers' CARGO_PKG_DESCRIPTION='Raw FFI bindings to platform libraries like libc.
  ' CARGO_PKG_HOMEPAGE='https://github.com/rust-lang/libc' CARGO_PKG_LICENSE='MIT OR Apache-2.0' CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=libc CARGO_PKG_README=README.md CARGO_PKG_REPOSITORY='https://github.com/rust-lang/libc' CARGO_PKG_RUST_VERSION='' CARGO_PKG_VERSION=0.2.149 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=2 CARGO_PKG_VERSION_PATCH=149 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/ws/target/debug/deps:/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib:/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/lib' /root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/bin/rustc --crate-name build_script_build /root/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libc-0.2.149/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=204 --crate-type bin --emit=dep-info,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="std"' -C metadata=96e5e627a3abf8c8 -C extra-filename=-96e5e627a3abf8c8 --out-dir /ws/target/debug/build/libc-96e5e627a3abf8c8 -L dependency=/ws/target/debug/deps --cap-lints warn` (exit status: 1)

[apiraino]

WG-prioritization assigning priority (Zulip discussion).

@rustbot label -I-prioritize +P-high T-compiler

[emlowe]

This works correctly in the riscv64/ubuntu:focal if you update ld to 2.41 - since it also works in Ubuntu 22, I'm guessing ld 2.38 is ok as well (that is the provided version in jammy)

So the problem seems limited to ld 2.34 which is the default provided in Ubuntu LTS 20.04. It's not that easy to update ld on a ubuntu distro as there don't seem to be an provided binary packages so one has to compile binutils locally

[Amanieu]

This was caused by the update to LLVM 17: it adds additional attributes to the object file which indicate which ISA extensions are used. These are parsed by cc and turned into a -march parameter passed to ld. However it seems that older versions of ld don't understand the new target feature attributes added by LLVM 17.