unsupported linker arg: `-exported_symbols_list`

[guw]

Zig Version

0.12.0

Steps to Reproduce and Observed Behavior

I am using a toolchain in Bazel which uses Zig to compile Rust. I am running into a problem on MacOS Arm64 only. It works fine on Linux.

This is because Rust only adds that option on Darwin like systems:
https://github.com/rust-lang/rust/blob/c23f07d8c56c51b5e634bda55daca2b073306340/compiler/rustc_codegen_ssa/src/back/linker.rs#L811

From inspecting the command line generated by Bazel for the Rust compilation, these options are passed to Zig:

  "-Wl,-exported_symbols_list" 
  "-Wl,/path/to/list" 

Zig fails with the following error:

  = note: error: unsupported linker arg: -exported_symbols_list

I checked main.zig and indeed it looks like the support for this option is missing.

Expected Behavior

Zig works without failing

[henderkes]

It also doesn't seem to support -Wl,--dynamic-list=/path/to/file on Linux. ld.lld installed from LLVM appears to support it (albeit with warnings that local symbols can't be turned global).

[ArchangelX360]

Hello people, we are in the exact same use case where we use a toolchain in Bazel which uses Zig to compile Rust. Did you manage to workaround it @guw?

[guw]

@ArchangelX360 I disabled Zig (hermetic_cc_toolchain) on MacOS. We are using the Bazel default there (non-hermetic).

[henderkes]

I use a zig-ld.lld wrapper that replaces the flag with -Wl,--export-dynamic.

It's not great, because it just bloats the resulting binary unnecessarily by turning every symbol dynamic.

[ArchangelX360]

Ok, thank you both! I hope the support for it will happen soon 🤞🏼

[anttiharju]

Using zig cc for Rust cross-compiling like suggested at https://actually.fyi/posts/zig-makes-rust-cross-compilation-just-work/ seemed too good to be true.

Encountered the error with https://github.com/anttiharju/compare-changes/tree/2cb94de6c18ada42a33a8f1426d352dc57a83ad5 when trying to

cargo add clap --features derive

followed by

TARGET=aarch64-apple-darwin CC="./.release/zcc.sh" cargo build --target "$TARGET"

but interestingly

cargo add clap

appears to be fine.

error output

  Compiling proc-macro2 v1.0.103
  Compiling unicode-ident v1.0.22
  Compiling quote v1.0.42
  Compiling heck v0.5.0
  Compiling syn v2.0.111
  Compiling clap_derive v4.5.49
error: linking with `/Users/antti/anttiharju/compare-changes/./.release/zcc.sh` failed: exit status: 1
  |
  = note:  "/Users/antti/anttiharju/compare-changes/./.release/zcc.sh" "-Wl,-exported_symbols_list" "-Wl,/var/folders/cs/w139gbxx41n01gt_j2w3g52r0000gn/T/rustcWUmtiL/list" "/var/folders/cs/w139gbxx41n01gt_j2w3g52r0000gn/T/rustcWUmtiL/symbols.o" "<16 object files omitted>" "/var/folders/cs/w139gbxx41n01gt_j2w3g52r0000gn/T/rustcWUmtiL/rmeta.o" "<1 object files omitted>" "/Users/antti/anttiharju/compare-changes/target/debug/deps/{libheck-b604e8bf463e779e,libsyn-15ddb0e80a0d3a0b,libquote-0b952226778a52fa,libproc_macro2-64f84243080c59a5,libunicode_ident-a509f239f93a2f1f}.rlib" "<sysroot>/lib/rustlib/aarch64-apple-darwin/lib/{libproc_macro-*,librustc_literal_escaper-*,librustc_std_workspace_std-*,libstd-*,libpanic_unwind-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,libcfg_if-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*,liblibc-*,librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-lSystem" "-lc" "-lm" "-arch" "arm64" "-mmacosx-version-min=11.3.0" "-o" "/Users/antti/anttiharju/compare-changes/target/debug/deps/libclap_derive-87d62b7bd9a4bf8f.dylib" "-Wl,-dead_strip" "-dynamiclib" "-nodefaultlibs"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: error: unsupported linker arg: -exported_symbols_list


error: could not compile `clap_derive` (lib) due to 1 previous error

$ zig version
0.14.1

[anttiharju]

@guw may be worth adding labels os-macos and zig cc for issue discoverability