`zig cc`: unsupported linker args (`--as-needed`, `-Bstatic`, `-Bdynamic`, and more)

[philipahlberg]

Zig Version

0.9.0-dev.1444+e2a2e6c14

Steps to Reproduce

In a nutshell:

$ CC=zig-cc; cargo install ripgrep --target aarch64-unknown-linux-gnu

zig-cc:

#! /bin/sh
zig cc -target aarch64-linux-gnu $@

The list of unsupported linker args is:

• --as-needed
• -Bstatic
• -Bdynamic
• -znoexecstack
• -zrelro
• -znow

See philipahlberg/rust-zig-cc-docker for exact steps to reproduce.

Expected Behavior

It compiles succesfully, installing the binary onto the machine.

Actual Behavior

error: linking with `zig-cc` failed: exit status: 1
  |
  = note: "zig-cc" "-m64" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.0.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.1.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.10.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.11.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.12.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.13.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.14.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.15.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.2.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.3.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.4.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.5.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.6.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.7.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.8.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.rg.06b2166d-cgu.9.rcgu.o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01.3zb7x5h83gps4ewl.rcgu.o" "-Wl,--as-needed" "-L" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps" "-L" "/tmp/cargo-installnriGM3/release/deps" "-L" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libnum_cpus-36e4020310cff317.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libgrep-d44cdc2a83b6f418.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libgrep_regex-d3e18b4a1f63be0a.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libgrep_printer-40ab05ecd46c3ff5.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libbase64-29cc4e04355e990f.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libserde_json-c6b34b534a688d52.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libryu-79e8a334f9d41d46.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libitoa-3ea878dd6c3f39ef.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libserde-2d356b4c07cc2654.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libgrep_searcher-a66c46bc63e18545.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libmemmap2-695259d505f60861.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libencoding_rs_io-05f12fb3fe3540d1.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libencoding_rs-4f1d034d1dfea496.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libbytecount-c6aba2f4e9097a9f.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libgrep_matcher-f2de09a669ddc60b.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libgrep_cli-09f0a207944dc72c.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libatty-6c32e73a59db6c45.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/liblibc-deb81cd183bf489b.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libtermcolor-54eec0f2c345eb5e.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libclap-5740de3b7c246e71.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libtextwrap-76be0833b16f4ded.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libunicode_width-61ed1d1c4af228f1.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libstrsim-87afea28899fb881.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libbitflags-346b928a6373e84f.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libignore-a48e2e9b2c1b9c37.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libcrossbeam_utils-0d4890e416d4cc48.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libwalkdir-041010beb3f43ac9.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libsame_file-e06f8f37e672ac4e.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libthread_local-fe1e38e113f0cc37.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libonce_cell-6bc255586f692b5c.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libglobset-f0dd44c472a216b8.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libfnv-f7ba8d2c0d18870a.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/liblog-d62c0c501a4c0277.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libcfg_if-bce0c30997effda1.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libregex-2cb84b6b69f0a69c.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libregex_syntax-6d75059dd0b825d0.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libbstr-e68ccf328a38811c.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/liblazy_static-9adf3f02eb04fff8.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libregex_automata-17697a180156e98d.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libaho_corasick-b2524b2f2f5c9e50.rlib" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/libmemchr-1304c82c3851ad91.rlib" "-Wl,--start-group" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-8adcca4f1427867b.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-8e7e86a00adbd98f.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libminiz_oxide-b69fd8507c8409af.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libadler-2dff396b99681a6b.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libobject-a78bd5aa183c7115.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libmemchr-846c64d5a2fbc5ee.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libaddr2line-24c09062b6dc787b.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgimli-ce93f351ca41a57b.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd_detect-6db383740f17d227.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-514cb174319eb6d4.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libhashbrown-37c1534c42bc4f8c.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-06d0f7780fda2fd9.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-a847e4fa8cfb7240.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcfg_if-88bb1ba4dd271224.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-08dbb7feabf67599.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-0b5a376b429677a6.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-2a6a2797f7a73818.rlib" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-0e3656b1fda5fd7b.rlib" "-Wl,--end-group" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-eecefd843a0dbc02.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-znoexecstack" "-L" "/usr/local/rustup/toolchains/nightly-aarch64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/tmp/cargo-installnriGM3/x86_64-unknown-linux-gnu/release/deps/rg-963575bbbc333e01" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs"
  = note: warning: unsupported linker arg: --as-needed
          warning: unsupported linker arg: -Bstatic
          warning: unsupported linker arg: -Bdynamic
          warning: unsupported linker arg: -znoexecstack
          warning: unsupported linker arg: -zrelro
          warning: unsupported linker arg: -znow
          ld.lld: error: unable to find library -lgcc_s


error: failed to compile `ripgrep v13.0.0`, intermediate artifacts can be found at `/tmp/cargo-installnriGM3`

Caused by:
  could not compile `ripgrep` due to previous error

Note: the error message is with an aarch64 host targeting x86_64. The description swaps these arround, assuming that is the more common case.

[leecannon]

It looks like cargo is passing gcc linker flags, im not 100% sure how to tell it to pass lld ones but i have found rust-lang/rust#40018 which might let you do it.

[srccde]

LLD supports these arguments just fine, although I'm not sure why it's telling you they were unsupported.
Anyway, those are only warnings. The error here is that the linker cannot find libgcc_s.

[philipahlberg]

The error here is that the linker cannot find libgcc_s.

I see. Do you know how I can fix this?

[nitsky]

Hi @philipahlberg there are two workarounds I am aware of:

1. Write a linker wrapper that swaps out -lgcc_s for -lunwind.
2. Use the unstable build-std feature in cargo to force the standard library to link to a linker-provided libunwind with build-std-features=system-llvm-libunwind.

The second option is much better but requires nightly.

[matpow2]

We are considering using zig cc as a cross-compiler for our games, and we also ran into the issue where --as-needed doesn't work as a linker flag currently. Should we create a new issue for this or does this issue cover it?

[andrewrk]

--as-needed landed in 4e5a88b.
-Bdynamic / -Bstatic landed in eec825c.
-zrelro, -znow, -znoexecstack landed in 2cdffc9.

for ld.lld: error: unable to find library -lgcc_s you'll have to figure out how to omit -lgcc_s from the command line; this argument should not be passed to zig cc. Although I would consider a proposal to make zig cc simply ignore this argument, since zig will always provide compiler_rt and libunwind as needed, fulfilling the same dependency thath -lgcc_s is intended to provide.