Port rustc codegen attrs #151336

Bryntet · 2026-01-18T19:42:25Z

Tracking issue: #131229

two more quick ones

r? @JonathanBrouwer

rustbot · 2026-01-18T19:42:28Z

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_hir/src/attrs

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann, @JonathanBrouwer

JonathanBrouwer · 2026-01-18T19:55:06Z

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

+impl<S: Stage> NoArgsAttributeParser<S> for RustcOffloadKernelParser {
+    const PATH: &[Symbol] = &[sym::rustc_offload_kernel];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::ForeignFn)]);


From #147936 it seems like Target::Fn should also be allowed. I don't think ForeignFn should be allowed. Note that an extern fn { ... } is still just a Target::Fn

This attribute does not seem to have a single test or usage in rustc which is fascinating

@Sa4dUs As the implementer of this attribute, what should the correct target list be? Only functions?

This attribute does not seem to have a single test or usage in rustc which is fascinating

I also found this fascinating, I thought that extern fn would be Target::ForeignFn

Rust has two related concepts:

A normal function that is exported with an abi:

extern "ABI" fn thing { }

A foreign function:

extern "ABI" { fn thing(); }

yes, accepting only Target:Function should be the way to go. this attribute is currently used to adjust functions written in rust to be compatible with offload.

we'll add some tests using this attr soon :)

cc @ZuseZ4 in case you have in mind any case where we might want to mark a ForeignFn

For this intrinsic it doesn't really make sense to support ForeignFn. It is there to run Rust code on a GPU.

Our other intrinsic, offload_args however only realy makes sense in combination with a ForeignFn. See e.g. https://github.com/rust-lang/rust/pull/150683/changes#diff-e92c562c10044d53fd41b1b06ef59a43087a6434e09fa8e667dea5b729d07726
However, I would expect that in most cases, people offload a safe wrapper around the ForeignFn (like I'm doing it in my test case there), instead of directly offloading the ForeignFn. So I think it should be fine to not allow ForeignFn at the moment, and only discuss it if users complain.

JonathanBrouwer

r=me after solving conflicts
@bors rollup d+

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JonathanBrouwer · 2026-01-19T07:38:50Z

@bors delegate

rust-bors · 2026-01-19T07:38:52Z

✌️ @Bryntet, you can now approve this pull request!

If @JonathanBrouwer told you to "r=me" after making some further change, then please make that change and post @bors r=JonathanBrouwer.

rustbot · 2026-01-19T09:41:07Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

Bryntet · 2026-01-19T09:41:13Z

@bors r=JonathanBrouwer

rust-bors · 2026-01-19T09:41:16Z

📌 Commit 3e731f7 has been approved by JonathanBrouwer

It is now in the queue for this repository.

@ghost

…uwer Rollup of 2 pull requests Successful merges: - #151336 (Port rustc codegen attrs) - #151359 (compiler: Temporarily re-export `assert_matches!` to reduce stabilization churn) r? @ghost

@JonathanBrouwer

Rollup merge of #151336 - port_rustc_codegen_attrs, r=JonathanBrouwer Port rustc codegen attrs Tracking issue: #131229 two more quick ones r? @JonathanBrouwer

…onathanBrouwer Port `#[patchable_function_entry]` to attr parser This is the last codegen attr (see rust-lang#151335 and rust-lang#151336)! Tracking issue: rust-lang#131229 currently this PR is rebased on rust-lang#151336 to make CI pass for the last commit to see the actual changes in this PR you can look [here](https://github.com/rust-lang/rust/pull/151340/changes/3e731f7e84301a898a36e46ee5e4845ff9bda98a..55111fb468808b733e97170a841217a67666ac33)

Rollup merge of #151340 - port_patchable_function_entry, r=JonathanBrouwer Port `#[patchable_function_entry]` to attr parser This is the last codegen attr (see #151335 and #151336)! Tracking issue: #131229 currently this PR is rebased on #151336 to make CI pass for the last commit to see the actual changes in this PR you can look [here](https://github.com/rust-lang/rust/pull/151340/changes/3e731f7e84301a898a36e46ee5e4845ff9bda98a..55111fb468808b733e97170a841217a67666ac33)

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jan 18, 2026

rustbot assigned JonathanBrouwer Jan 18, 2026

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Tracking issue: Attribute refactor #131229

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Port #[patchable_function_entry] to attr parser #151340

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Bryntet force-pushed the port_rustc_codegen_attrs branch 3 times, most recently from ecc0410 to b52ecfe Compare January 18, 2026 22:16

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Bryntet added 2 commits January 19, 2026 10:40

Port #[rustc_nounwind] to attr parser

03b8b68

Port #[rustc_offload_kernel] to attr parser

3e731f7

Bryntet force-pushed the port_rustc_codegen_attrs branch from b52ecfe to 3e731f7 Compare January 19, 2026 09:41

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 19, 2026

JonathanBrouwer mentioned this pull request Jan 19, 2026

Rollup of 2 pull requests #151363

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rust-bors bot merged commit a77d6b8 into rust-lang:main Jan 19, 2026
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rustbot added this to the 1.95.0 milestone Jan 19, 2026

rust-timer added a commit that referenced this pull request Jan 19, 2026

Unrolled build for #151336

f78dde6

Rollup merge of #151336 - port_rustc_codegen_attrs, r=JonathanBrouwer Port rustc codegen attrs Tracking issue: #131229 two more quick ones r? @JonathanBrouwer

Bryntet deleted the port_rustc_codegen_attrs branch January 19, 2026 16:35

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Port rustc codegen attrs #151336

Port rustc codegen attrs #151336

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