Skip to content

linker: Remove special case for rust-lld in detect_self_contained_mingw #149590

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
bors merged 1 commit into from
Dec 3, 2025
Merged

linker: Remove special case for rust-lld in detect_self_contained_mingw #149590

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 0 additions & 4 deletions compiler/rustc_codegen_ssa/src/back/link.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1763,10 +1763,6 @@ fn link_output_kind(sess: &Session, crate_type: CrateType) -> LinkOutputKind {

// Returns true if linker is located within sysroot
fn detect_self_contained_mingw(sess: &Session, linker: &Path) -> bool {
// Assume `-C linker=rust-lld` as self-contained mode
if linker == Path::new("rust-lld") {
return true;
}

@bjorn3 bjorn3 Dec 3, 2025

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Below only the sysroot from which we get the standard library is checked, not the fallback sysroot that rustc itself is contained in. rust-lld is likely to be contained only in the latter if the former is overriden.

@mati865 mati865 Dec 3, 2025

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm fairly sure from my tests the sysroot would point at ~/.rustup/toolchains/<toolchain>.

If I read

rust/compiler/rustc_session/src/filesearch.rs

Line 190 in 8202d11

fn default_from_rustc_driver_dll() -> Result<PathBuf, String> {
right, it would indeed stirp all the subdirectories.

@bjorn3 bjorn3 Dec 3, 2025 •
edited
Loading

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The code below only strips sess.opts.sysroot.path(), which only returns the value explicitly passed to --sysroot if passed, only returning the fallback sysroot when it isn't passed.

rust/compiler/rustc_session/src/config.rs

Lines 1345 to 1348 in 8202d11

/// Return explicit sysroot if it was passed with `--sysroot`, or default sysroot otherwise.
pub fn path(&self) -> &Path {
self.explicit.as_deref().unwrap_or(&self.default)
}
You need sess.opts.sysroot.all_paths() to check both.

@mati865 mati865 Dec 3, 2025

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good point, but is --sysroot ever passed to rustc when building natively (host == target)?

@bjorn3 bjorn3 Dec 3, 2025

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

There are legitimate reasons to pass it when building natively. For example miri does for it's copy of the standard library that contains MIR for all functions (though it doesn't need a linker). cargo build -Zbuild-std doesn't use --sysroot currently, but I think it should pass --sysroot /dev/null or something like that to prevent accidentally picking up libraries from the sysroot. The only thing that leads to is lang item conflicts. --sysroot /dev/null would give nicer error messages.

@mati865 mati865 Dec 3, 2025

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

--sysroot /dev/null would break all cases of implicit self-contained detection, not just rust-lld. I mean, there is no obvious issue caused by this PR, not that there is no general issue with implicit self-contained detection.

@bjorn3 bjorn3 Dec 3, 2025

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Right. The self-contained components are themself only looked up in --sysroot. Didn't think of that.

let linker_with_extension = if cfg!(windows) && linker.extension().is_none() {
linker.with_extension("exe")
} else {
Expand Down
Loading