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Horrible hack to make codegen backends "work" during check

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Jakub Beránek 2025-07-05 12:42:47 +02:00
parent 775c970aae
commit 18768f0888
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GPG key ID: 909CD0D26483516B
1 changed files with 32 additions and 11 deletions
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43
src/bootstrap/src/core/build_steps/compile.rs
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@ -1741,17 +1741,19 @@ fn copy_codegen_backends_to_sysroot(
}
let stamp = build_stamp::codegen_backend_stamp(builder, compiler, target, backend);
let dylib = t!(fs::read_to_string(stamp.path()));
let file = Path::new(&dylib);
let filename = file.file_name().unwrap().to_str().unwrap();
// change `librustc_codegen_cranelift-xxxxxx.so` to
// `librustc_codegen_cranelift-release.so`
let target_filename = {
let dash = filename.find('-').unwrap();
let dot = filename.find('.').unwrap();
format!("{}-{}{}", &filename[..dash], builder.rust_release(), &filename[dot..])
};
builder.copy_link(file, &dst.join(target_filename), FileType::NativeLibrary);
if stamp.path().exists() {
let dylib = t!(fs::read_to_string(stamp.path()));
let file = Path::new(&dylib);
let filename = file.file_name().unwrap().to_str().unwrap();
// change `librustc_codegen_cranelift-xxxxxx.so` to
// `librustc_codegen_cranelift-release.so`
let target_filename = {
let dash = filename.find('-').unwrap();
let dot = filename.find('.').unwrap();
format!("{}-{}{}", &filename[..dash], builder.rust_release(), &filename[dot..])
};
builder.copy_link(file, &dst.join(target_filename), FileType::NativeLibrary);
}
}
}
@ -2162,6 +2164,25 @@ impl Step for Assemble {
continue; // Already built as part of rustc
}
// FIXME: this is a horrible hack used to make `x check` work when other codegen
// backends are enabled.
// `x check` will check stage 1 rustc, which copies its rmetas to the stage0 sysroot.
// Then it checks codegen backends, which correctly use these rmetas.
// Then it needs to check std, but for that it needs to build stage 1 rustc.
// This copies the build rmetas into the stage0 sysroot, effectively poisoning it,
// because we then have both check and build rmetas in the same sysroot.
// That would be fine on its own. However, when another codegen backend is enabled,
// then building stage 1 rustc implies also building stage 1 codegen backend (even if
// it isn't used for anything). And since that tries to use the poisoned
// rmetas, it fails to build.
// We don't actually need to build rustc-private codegen backends for checking std,
// so instead we skip that.
// Note: this would be also an issue for other rustc-private tools, but that is "solved"
// by check::Std being last in the list of checked things (see
// `Builder::get_step_descriptions`).
if builder.kind == Kind::Check && builder.top_stage == 1 {
continue;
}
builder.ensure(CodegenBackend {
compiler: build_compiler,
target: target_compiler.host,