Implement `core::arch::return_address` and tests by chorman0773 · Pull Request #154972 · rust-lang/rust

chorman0773 · 2026-04-07T23:25:45Z

Tracking issue: #154966

Implements libs-team#768

rustbot · 2026-04-07T23:25:49Z

Some changes occurred to the intrinsics. Make sure the CTFE / Miri interpreter
gets adapted for the changes, if necessary.

cc @rust-lang/miri, @RalfJung, @oli-obk, @lcnr

rustbot · 2026-04-07T23:25:51Z

r? @Mark-Simulacrum

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chorman0773 · 2026-04-11T03:34:41Z

Helpful comment, thanks rustbot 😐

Mark-Simulacrum

I'm not a huge fan of the doc comment's language. Could you try iterating on it a bit?

I think adding the cranelift implementation in this PR would also make sense (and maybe a gcc backend implementation -- not sure how easy that is?).

r=me with at least the comment fixed.

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rustbot · 2026-04-11T16:12:37Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

rustbot · 2026-04-13T18:48:34Z

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

chorman0773 · 2026-04-13T18:50:24Z

I've changed the wording of the comment arround a bit, in part to make it more clear than returning null is something the compiler tries to do if it can't return a useful value for some reason, but doesn't guarantee. I've also added a cranelift impl. I'll figure out gcc/miri in a future PR.

r=@Mark-Simulacrum

@rustbot ready

Mark-Simulacrum · 2026-04-18T20:15:27Z

r=me with commits squashed

r? me

Fix typo Apply suggestions from code review Wording/docs changes. Co-authored-by: Ralf Jung <post@ralfj.de> Change signature according to Ralf's comment Fix call to `core::intrinsics::return_address()` according to the new signature Add cranelift implementation for intrinsic Change wording on `return_address!()` to be clear that returning a null pointer is best-effort. Fix formatting of doc comment Fix mistake in cranelift codegen

…-Simulacrum Implement `core::arch::return_address` and tests Tracking issue: rust-lang#154966 Implements libs-team#768

Rollup of 9 pull requests Successful merges: - #155370 (Add regression test for dead code elimination with drop + panic) - #154823 (Replace the spdx-rs dependency with a minimal in-tree SPDX tag-value parser) - #154972 (Implement `core::arch::return_address` and tests) - #155294 (Add test for coalescing of diagnostic attribute duplicates) - #155352 (triagebot.toml: Sync `assign.owners` with `autolabel."T-compiler"`) - #155431 (Add temporary scope to assert_matches) - #152995 (ACP Implementation of PermissionsExt for Windows ) - #153873 (deprecate `std::char` constants and functions) - #154865 (libtest: use binary search for --exact test filtering)

jhpratt · 2026-04-19T08:14:53Z

@bors r-

#155506 (comment)

rust-bors · 2026-04-19T08:14:59Z

This pull request was unapproved.

This PR was contained in a rollup (#155506), which was unapproved.

chorman0773 · 2026-04-19T13:14:33Z

Oh ok. lang-ref forgets to mention that the intrinsic doesn't work on some targets (wasm).

chorman0773 · 2026-04-19T15:38:46Z

@rustbot ready

Mark-Simulacrum · 2026-04-19T16:12:30Z

@bors r+ rollup=iffy

rust-bors · 2026-04-19T16:12:32Z

📌 Commit 592e9c0 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

Implement `core::arch::return_address` and tests Tracking issue: #154966 Implements libs-team#768

rust-bors · 2026-04-20T00:32:39Z

💔 Test for ec8f768 failed: CI. Failed job:

auto - x86_64-gnu-aux (web logs, enhanced plaintext logs)

RalfJung · 2026-04-22T06:26:58Z

 ///
 /// ## Example
 /// ```
+/// # #![cfg(not(miri))] // FIXME: Figure out how to make miri work before stabilizing this macro


Miri should probably just pick an arbitrary 64bit integer and return that? Or is that too adversarial and we should return null?

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It probably should (though I see it doing either). Right now, I'd like something landed though. My plan is to figure out miri (and codegen_gcc) before stabilization.

(I suppose we could briefly discuss whether it is "fine" to return just null tomorrow)

That's more of a Miri thing than an opsem thing so I'd prefer to discuss that in the PR which implements it.

Fair. In any case, the main thing a random implementation would detect is someone doing a null test, then some form of stupid shenanigans like transmuting to a function pointer and calling it (or .read()ing it). Raw .read() or transmute/call would be detected since null pointer would trip anyways.

chorman0773 · 2026-04-23T01:30:47Z

@rustbot ready

rustbot assigned Mark-Simulacrum Apr 7, 2026

chorman0773 mentioned this pull request Apr 7, 2026

Tracking Issue for core::arch::return_address #154966

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Rollup merge of rust-lang#154972 - chorman0773:return_address, r=Mark…

e7705cf

…-Simulacrum Implement `core::arch::return_address` and tests Tracking issue: rust-lang#154966 Implements libs-team#768

jhpratt mentioned this pull request Apr 19, 2026

Rollup of 9 pull requests #155506

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Do not generate llvm.returnaddress on wasm

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Auto merge of #154972 - chorman0773:return_address, r=Mark-Simulacrum

ec8f768

Implement `core::arch::return_address` and tests Tracking issue: #154966 Implements libs-team#768

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Supress return_address test on miri

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