-Clink-arg=-fuse-ld=lld reports 'cannot find ld'

[jyn514]

What it actually means is 'cannot find lld', which is different - you can have one installed but not the other.

$ rustc -Clink-arg=-fuse-ld=lld build.rs 
error: linking with `cc` failed: exit code: 1
  |
  = note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m64" "-Wl,--eh-frame-hdr" "-L" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "build.build.7rcbfp3g-cgu.0.rcgu.o" "build.build.7rcbfp3g-cgu.1.rcgu.o" "build.build.7rcbfp3g-cgu.10.rcgu.o" "build.build.7rcbfp3g-cgu.11.rcgu.o" "build.build.7rcbfp3g-cgu.12.rcgu.o" "build.build.7rcbfp3g-cgu.13.rcgu.o" "build.build.7rcbfp3g-cgu.14.rcgu.o" "build.build.7rcbfp3g-cgu.15.rcgu.o" "build.build.7rcbfp3g-cgu.2.rcgu.o" "build.build.7rcbfp3g-cgu.3.rcgu.o" "build.build.7rcbfp3g-cgu.4.rcgu.o" "build.build.7rcbfp3g-cgu.5.rcgu.o" "build.build.7rcbfp3g-cgu.6.rcgu.o" "build.build.7rcbfp3g-cgu.7.rcgu.o" "build.build.7rcbfp3g-cgu.8.rcgu.o" "build.build.7rcbfp3g-cgu.9.rcgu.o" "-o" "build" "build.3o9xbt4o0msgng42.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs" "-L" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-6f5658153d127ddd.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-b69e89b2ef7e009e.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libminiz_oxide-fe971cf9622d0c47.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libadler-9ff49e5df977573d.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libobject-323dea4ee1c9a010.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libaddr2line-f12d17a047776008.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgimli-3d968aa3120f6a27.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-22cd238a7814521c.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libhashbrown-f2c707309e5edc5c.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-6b6b4b2bc151fc5a.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-32b57ee4d7c8dc07.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcfg_if-d9f2cb19c79e847e.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-3ccc4a4f3013e9ef.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-aa547327a7679d28.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-90996f4879673567.rlib" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-9ea09a899c3eda46.rlib" "-Wl,--end-group" "/home/joshua/.local/lib/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-ea377e9224b11a8a.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-fuse-ld=lld"
  = note: collect2: fatal error: cannot find 'ld'
          compilation terminated.

This comes from gcc, so you could make a reasonable case for this being an upstream bug.

[nagisa]

Does gcc support using lld as a linker?

-fuse-ld= does not tell the gcc (or clang) to use the specified value as a linker executable. It tells it to use the certain family of linkers as a linker. e.g. -fuse-ld=gold will end up invoking ld.gold. Its a lot like the -Clinker-flavor argument of rustc.

upstream bug

Yeah I don't think there's anything rustc can do about the linker having ungreat diagnostics, accepting flags it does not expect or ignoring what it does not understand.

[jyn514]

Does gcc support using lld as a linker?

It does - the issue was I didn't have lld installed.

Ok, I'll open an upstream issue.

[mati865]

-fuse-ld= does not tell the gcc (or clang) to use the specified value as a linker executable.

With Clang one can use LLD command like that -fuse-ld=lld-11 to use specific version, you can even provide the path to LLD.
GCC accepts only linker name (without version).

This issue is not actionable by Rust.

[jyn514]

This issue is not actionable by Rust.

I opened https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99878 and https://bugs.llvm.org/show_bug.cgi?id=49814.