Bootstrap without creating a config.toml fails with missing rust-objcopy

[wesleywiser]

After cloning, I expected python3 x.py test --stage 1 tests/ui to succeed but instead I got many test failures like this one:

---- [ui] tests/ui/async-await/track-caller/panic-track-caller.rs#afn stdout ----

error in revision `afn`: test compilation failed although it shouldn't!
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/Users/wesley/Code/rust/build/aarch64-apple-darwin/stage1/bin/rustc" "/Users/wesley/Code/rust/tests/ui/async-await/track-caller/panic-track-caller.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/Users/wesley/.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/Users/wesley/Code/rust/vendor" "--sysroot" "/Users/wesley/Code/rust/build/aarch64-apple-darwin/stage1" "--target=aarch64-apple-darwin" "--cfg" "afn" "--check-cfg" "cfg(FALSE,afn,cls,nofeat)" "-O" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "-o" "/Users/wesley/Code/rust/build/aarch64-apple-darwin/test/ui/async-await/track-caller/panic-track-caller.afn/a" "-A" "internal_features" "-Crpath" "-Cdebuginfo=0" "-Lnative=/Users/wesley/Code/rust/build/aarch64-apple-darwin/native/rust-test-helpers" "--edition=2021"
stdout: none
--- stderr -------------------------------
error: unable to run `rust-objcopy`: No such file or directory (os error 2)

error: aborting due to 1 previous error
------------------------------------------

However, if I create a config.toml by cp config.example.toml config.toml, then the problem goes away.

I instrumented the code here with a println!() and I can see that when config.toml exists, this block runs but when config.toml does not exist, it does not run:

rust/src/bootstrap/src/core/build_steps/compile.rs

Lines 1980 to 1988 in b71fb5e

	// `llvm-strip` is used by rustc, which is actually just a symlink to `llvm-objcopy`, so
	// copy and rename `llvm-objcopy`.
	//
	// But only do so if llvm-tools are enabled, as bootstrap compiler might not contain any
	// LLVM tools, e.g. for cg_clif.
	// See <https://github.com./rust-lang/rust/issues/132719>.
	let src_exe = exe("llvm-objcopy", target_compiler.host);
	let dst_exe = exe("rust-objcopy", target_compiler.host);
	builder.copy_link(&libdir_bin.join(src_exe), &libdir_bin.join(dst_exe));

Possibly related to #132720 cc @jieyouxu

Meta

Cloned rust-lang/rust at b71fb5e

Host is aarch64-apple-darwin

[jieyouxu]

Only copy, rename and link llvm-objcopy if llvm tools are enabled #132720 fixes Shipping llvm-strip w/ a symlink breaks when bootstrap compiler doesn't contain any LLVM tools #132719 because cg_clif doesn't have llvm bin tools in the bootstrap compiler.

That was because bootstrap/codegen_ssa: ship llvm-strip and use it for -Cstrip #131405 was introduced to fix Hard-coded strip path breaks Linux -> Darwin builds #131206.

And strip was hard-coded before by Fix up setting strip = true in Cargo.toml makes build scripts fail in… #130781 because using a random strip from PATH on macOS can mean using a broken homebrew strip¹ as reported in Setting strip = true in Cargo.toml makes build scripts fail in release mode on MacOS #110536.

If you are using binutils strip to strip arm64 macOS binaries, it does not work fine. It produces broken binaries with invalid code signature. On arm64 macOS mandates the use of code signatures, so "unsigned" binaries use an ad-hoc code signature, but binutils seems to forget to update the ad-hoc code signature when modifying binaries. This is exactly the problem #130781 fixed by forcing XCode's strip to be used instead.
-- #131206 (comment)

Footnotes

1. AFAIK it's still broken ↩

[jieyouxu]

I'm not very sure what's the proper fix here... Default config.toml-less macOS builds to acquire CI llvm and llvm bin tools?
Zulip thread: https://rust-lang.zulipchat.com/#narrow/channel/326414-t-infra.2Fbootstrap/topic/Bootstrap.20w.2Fout.20config.2Etoml.20fails.20with.20missing.20rust-objcopy

[jieyouxu]

Right... because we hard code this to rust-objcopy in cg_ssa:

rust/compiler/rustc_codegen_ssa/src/back/link.rs

Lines 1106 to 1107 in e6c1e14

	if sess.target.is_like_osx {
	let stripcmd = "rust-objcopy";

[jieyouxu]

I instrumented the code here with a println!() and I can see that when config.toml exists, this block runs but when config.toml does not exist, it does not run

Apparently without a config.toml llvm_tools_enabled is false by default