rustc-1.88.0 does not build using external LLVM due to missing rust-lld

When building using an external LLVM, the build fails due to a missing rust-lld even when lld is present in path.

Summary

Here is the end of the build log:

Dist rust-docs-1.88.0-x86_64-apple-darwin
	finished in 27.638 seconds
Installing stage2 docs (x86_64-apple-darwin)
install: creating uninstall script at /tmp/dst.rustc/usr/local/lib/rustlib/uninstall.sh
install: installing component 'rust-docs'

    rust docs installed.

Dist rust-std-1.88.0-x86_64-apple-darwin
	finished in 0.442 seconds
Installing stage2 std (x86_64-apple-darwin)
install: creating uninstall script at /tmp/dst.rustc/usr/local/lib/rustlib/uninstall.sh
install: installing component 'rust-std-x86_64-apple-darwin'

    rust std installed.


thread 'main' panicked at src/bootstrap/src/lib.rs:1779:24:
src.symlink_metadata() failed with No such file or directory (os error 2) ("src = /tera/tera/debo/Projects/rustc/rustc-1.88.0-src/build/x86_64-apple-darwin/stage2/lib/rustlib/x86_64-apple-darwin/bin/rust-lld")
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Panic was initiated from src/bootstrap/src/lib.rs:1779:24
Build completed unsuccessfully in 0:26:40

Command used

DESTDIR=/tmp/dst.rustc x.py install

Note the error from bootstrap in the log:

Warning: LLD is enabled when using external llvm-config. LLD will not be built and copied to the sysroot.

Expected behaviour

I expected it to build.

Actual behaviour

Failed to build. See above log snippet. Entire log is attached.

rustc-1.88-log.txt

Bootstrap configuration (bootstrap.toml)

I am using a system LLVM llvm-20.1.7:

llvm-config = "/usr/local/bin/llvm-config"

Operating system

macOS 10.12.6

HEAD

6b00bc3880198600130e1cf62b8f8a93494488cc

I was able to successfully complete the build by doing the following:

Copy ldd to build/x86_64-apple-darwin/stage2/lib/rustlib/x86_64-apple-darwin/bin/rust-lld

Create a directory build/x86_64-apple-darwin/stage2/lib/rustlib/x86_64-apple-darwin/bin/gcc-ld

Inside that directory, hardlink ld.lld, ld64.lld, lld-link, wasm-ld to rust-lld

The question is: If the build requires it, then why isn't the stage2 directory correctly populated?

Note that I also worked around the issue in #139400.

Note: issue is not Darwin specific, I see the same on Linux using system installed llvm.

In case it's useful here's full backtrace:

backtrace

thread 'main' panicked at src/bootstrap/src/lib.rs:1779:24:
src.symlink_metadata() failed with No such file or directory (os error 2) ("src = /home/users/builder/rpm/BUILD/rust-1.88.0-build/rustc-1.88.0-src/build/aarch64-unknown-linux-gnu/stage2/lib/rustlib/aarch64-unknown-linux-gnu/bin/rust-lld")
stack backtrace:
   0:     0xaaaab09917c8 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h887f38dba00b5b2a
   1:     0xaaaab09af59c - core::fmt::write::h2a34afd9df67012f
   2:     0xaaaab095d420 - std::io::Write::write_fmt::hffb2973b22859382
   3:     0xaaaab09916c4 - std::sys::backtrace::BacktraceLock::print::h9625458d31d2622b
   4:     0xaaaab0995c4c - std::panicking::default_hook::{{closure}}::h6a1a2410bed9bb2f
   5:     0xaaaab0995b44 - std::panicking::default_hook::h2781aa184b70a849
   6:     0xaaaab099618c - std::panicking::rust_panic_with_hook::h6924c0fb82d17bc5
   7:     0xaaaab0991bd4 - std::panicking::begin_panic_handler::{{closure}}::hdebafdaae531983f
   8:     0xaaaab0991a1c - std::sys::backtrace::__rust_end_short_backtrace::h9fd1b6471baf08f9
   9:     0xaaaab0995ce8 - __rustc[aaf4a02f2f9ab86b]::rust_begin_unwind
  10:     0xaaaaaff559b4 - core::panicking::panic_fmt::h60a77bb2c5cb27f3
  11:     0xaaaab01c5300 - bootstrap::Build::copy_link_internal::hdbdbd10eaa6bb9af
  12:     0xaaaab01c456c - bootstrap::Build::copy_link::h4d03dd04aad54a94
  13:     0xaaaab0200344 - <bootstrap::core::build_steps::dist::Rustc as bootstrap::core::builder::Step>::run::prepare_image::he9cfea7987feaea1
  14:     0xaaaab01ff6c4 - <bootstrap::core::build_steps::dist::Rustc as bootstrap::core::builder::Step>::run::h3031a9df80cf4512
  15:     0xaaaab00ce164 - bootstrap::core::builder::Builder::ensure::h85cf508fac3dfa57
  16:     0xaaaab01ff5b0 - <bootstrap::core::build_steps::dist::Rustc as bootstrap::core::builder::Step>::make_run::hd7eef2b4e3696bb5
  17:     0xaaaab04c3a34 - bootstrap::core::builder::StepDescription::maybe_run::h96f8253d4fbf8942
  18:     0xaaaab04c4658 - bootstrap::core::builder::StepDescription::run::h1d8ef1312383bc01
  19:     0xaaaab04c951c - bootstrap::core::builder::Builder::run_step_descriptions::hc5e4488356b98424
  20:     0xaaaab04c92dc - bootstrap::core::builder::Builder::execute_cli::hb6e5e1cdc3baf344
  21:     0xaaaab01be984 - bootstrap::Build::build::h046ecdaff4a19fca
  22:     0xaaaaaff5a530 - bootstrap::main::h06cef34dae0473b8
  23:     0xaaaaaff5d1b0 - core::ops::function::FnOnce::call_once::hf1a679c885cbfb5c
  24:     0xaaaaaff5ce58 - std::sys::backtrace::__rust_begin_short_backtrace::h28d569c780c0ed5d
  25:     0xaaaaaff5c0ec - std::rt::lang_start::{{closure}}::h4e3747e7ac742d62
  26:     0xaaaab0997ba4 - std::rt::lang_start_internal::h8706a62a5edce61c
  27:     0xaaaaaff5c0d4 - std::rt::lang_start::h4b13ebde88700676
  28:     0xaaaaaff5bab8 - main
  29:     0xffff969d2218 - <unknown>
  30:     0xffff969d22f4 - __libc_start_main
  31:     0xaaaaaff560f0 - _start

@Kobzol

#139853 might possibly be related (cc @Kobzol)

Auto merge of #143175 - Kobzol:bootstrap-lld-external-llvm-config, r=…

Thanks for the report, this is indeed a bootstrap bug. I'll try fixing it in #143175.

#143175 will solve this for the future. For 1.88.0, please set rust.lld = false in bootstrap.toml.

@Kobzol

@Kobzol I'm not sure if i follow linked PR but I suppose rust.lld = false will be required in later releases too, is that correct? If yes would it be possible to change rust.lld default to !system_llvm?

Rollup merge of rust-lang#143175 - Kobzol:bootstrap-lld-external-llvm…

Oh, good point, I didn't realize it's in fact enabled by default in dist. I'll change the default as you said.

#143255 should resolve the default.

Auto merge of #143255 - Kobzol:disable-lld-by-default, r=<try>

Unrolled build for #143175

Rollup merge of #143175 - Kobzol:bootstrap-lld-external-llvm-config, …

Rollup merge of rust-lang#143255 - Kobzol:disable-lld-by-default, r=j…

Unrolled build for #143255

rust-1.88: set rust.lld to false to fix FTBFS

up to 1.88.0

Rollup merge of #143175 - Kobzol:bootstrap-lld-external-llvm-config, …

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rustc-1.88.0 does not build using external LLVM due to missing rust-lld #143076

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Expected behaviour

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Operating system

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rustc-1.88.0 does not build using external LLVM due to missing rust-lld #143076

Description

Summary

Command used

Expected behaviour

Actual behaviour

Bootstrap configuration (bootstrap.toml)

Operating system

HEAD

Activity

debohman commented on Jun 27, 2025

debohman commented on Jun 27, 2025

jpalus commented on Jun 27, 2025

jpalus commented on Jun 27, 2025

jpalus commented on Jun 28, 2025

Kobzol commented on Jun 29, 2025

Kobzol commented on Jun 30, 2025

jpalus commented on Jun 30, 2025

Kobzol commented on Jun 30, 2025

Kobzol commented on Jun 30, 2025

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