Fix passing/returning structs with the 64-bit SPARC ABI by beetrees · Pull Request #142680 · rust-lang/rust

beetrees · 2025-06-18T15:11:25Z

Fixes the 64-bit SPARC part of #115609 by replacing the current implementation with a new implementation modelled on the RISC-V calling convention code (SPARC ABI reference).

Pinging sparcv9-sun-solaris target maintainers: @psumbera @kulikjak
Fixes #115336
Fixes #115399
Fixes #122620
Fixes #147883
r? @workingjubilee

rustbot · 2025-06-18T15:11:29Z

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beetrees · 2025-06-18T15:13:23Z

r? @bjorn3

beetrees · 2025-06-18T18:49:07Z

Note that there are currently two places that Clang and GCC disagree AFAIK:

Clang fails to correctly align 16-byte structs when passing them as arguments, whereas GCC correctly aligns them. As the specification states that the structs must be aligned, I've filed an Clang bug at Clang: 64-bit SPARC doesn't align struct arguments as required by ABI llvm/llvm-project#144709.
Clang passes floating point fields in packed structs in floating point register if the field is aligned within the argument as a whole, whereas GCC always passes packed structs in integer registers. The specification doesn't consider the existence of packed structs, however in my opinion Clang's interpretation seems more correct so that's what I've implemented in this PR. Issues for Rust, Clang and GCC.

psumbera · 2025-06-19T14:58:27Z

Thank you for doing this! My knowledge in this area is rather limited.

I was able to build latest Rust sources with your fix on top on Solaris 11.4 SPARC. Then I used this version to build Firefox on Solaris. There was no problem. Firefox also worked as expected.

I also tested some problematic cases which I was handling few years ago (https://github.com/psumbera/rust-sparc64-abi-tests). All seemed to be ok.

bjorn3 · 2025-07-03T11:23:02Z

I don't have time to properly review this right now.

r? compiler

bors · 2025-07-06T14:13:49Z

☔ The latest upstream changes (presumably #143521) made this pull request unmergeable. Please resolve the merge conflicts.

beetrees · 2025-07-06T14:45:16Z

Rebased

bors · 2025-07-22T22:48:52Z

☔ The latest upstream changes (presumably #144249) made this pull request unmergeable. Please resolve the merge conflicts.

wesleywiser · 2025-08-28T14:48:36Z

Hi @workingjubilee, are you still interested in reviewing this? If not, we can reroll for a different reviewer. Thanks!

tgross35 · 2025-09-05T02:17:41Z

Looks like there is a Clang fix in llvm/llvm-project#155829

tests/assembly-llvm/sparc-struct-abi.rs

compiler/rustc_target/src/callconv/sparc64.rs

tests/assembly-llvm/sparc-struct-abi.rs

compiler/rustc_target/src/callconv/sparc64.rs

workingjubilee · 2025-09-10T04:26:47Z

Sorry about that, currently in catchup mode so I am going to delegate, yes.

r? @tgross35

rustbot · 2026-02-10T10:39:55Z

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.

tgross35

Awesome, lgtm

View changes since this review

Co-authored-by: beetrees <b@beetr.ee>

folkertdev · 2026-02-10T20:48:58Z

@bors r=tgross35

rust-bors · 2026-02-10T20:49:01Z

📌 Commit c9b5c93 has been approved by tgross35

It is now in the queue for this repository.

@psumbera

… r=tgross35 Fix passing/returning structs with the 64-bit SPARC ABI Fixes the 64-bit SPARC part of rust-lang#115609 by replacing the current implementation with a new implementation modelled on the RISC-V calling convention code ([SPARC ABI reference](https://sparc.org/wp-content/uploads/2014/01/SCD.2.4.1.pdf.gz)). Pinging `sparcv9-sun-solaris` target maintainers: @psumbera @kulikjak Fixes rust-lang#115336 Fixes rust-lang#115399 Fixes rust-lang#122620 Fixes rust-lang#147883 r? @workingjubilee

@psumbera

… r=tgross35 Fix passing/returning structs with the 64-bit SPARC ABI Fixes the 64-bit SPARC part of rust-lang#115609 by replacing the current implementation with a new implementation modelled on the RISC-V calling convention code ([SPARC ABI reference](https://sparc.org/wp-content/uploads/2014/01/SCD.2.4.1.pdf.gz)). Pinging `sparcv9-sun-solaris` target maintainers: @psumbera @kulikjak Fixes rust-lang#115336 Fixes rust-lang#115399 Fixes rust-lang#122620 Fixes rust-lang#147883 r? @workingjubilee

@psumbera

… r=tgross35 Fix passing/returning structs with the 64-bit SPARC ABI Fixes the 64-bit SPARC part of rust-lang#115609 by replacing the current implementation with a new implementation modelled on the RISC-V calling convention code ([SPARC ABI reference](https://sparc.org/wp-content/uploads/2014/01/SCD.2.4.1.pdf.gz)). Pinging `sparcv9-sun-solaris` target maintainers: @psumbera @kulikjak Fixes rust-lang#115336 Fixes rust-lang#115399 Fixes rust-lang#122620 Fixes rust-lang#147883 r? @workingjubilee

Rollup of 17 pull requests Successful merges: - #142415 (Add note when inherent impl for a alias type defined outside of the crate) - #142680 (Fix passing/returning structs with the 64-bit SPARC ABI) - #150768 (Don't compute FnAbi for LLVM intrinsics in backends) - #151152 (Add FCW for derive helper attributes that will conflict with built-in attributes) - #151814 (layout: handle rigid aliases without params) - #151863 (Borrowck: simplify diagnostics for placeholders) - #152159 (Add note for `?Sized` params in int-ptr casts diag) - #152434 (Clarify names of `QueryVTable` functions for "executing" a query) - #152478 (Remove tm_factory field from CodegenContext) - #152498 (Partially revert "resolve: Update `NameBindingData::vis` in place") - #152316 (fix: add continue) - #152394 (Correctly check if a macro call is actually a macro call in rustdoc highlighter) - #152425 (Port #![test_runner] to the attribute parser) - #152481 (Use cg_ssa's produce_final_output_artifacts in cg_clif) - #152485 (fix issue#152482) - #152495 (Clean up some subdiagnostics) - #152502 (Implement `BinaryHeap::from_raw_vec`)

@psumbera

Rollup merge of #142680 - beetrees:sparc64-float-struct-abi, r=tgross35 Fix passing/returning structs with the 64-bit SPARC ABI Fixes the 64-bit SPARC part of #115609 by replacing the current implementation with a new implementation modelled on the RISC-V calling convention code ([SPARC ABI reference](https://sparc.org/wp-content/uploads/2014/01/SCD.2.4.1.pdf.gz)). Pinging `sparcv9-sun-solaris` target maintainers: @psumbera @kulikjak Fixes #115336 Fixes #115399 Fixes #122620 Fixes #147883 r? @workingjubilee

@RalfJung

…at-test, r=RalfJung sparc64: enable abi compatibility test fixes rust-lang#115336 We can now remove the exceptions for sparc64 from the abi compatibility tests (since rust-lang#142680). I was also able to remove a cfg for mips64. The remaining (tested) issues seem to be around how `f64` is handled there. cc @RalfJung r? tgross35

@RalfJung

…at-test, r=RalfJung sparc64: enable abi compatibility test fixes rust-lang#115336 We can now remove the exceptions for sparc64 from the abi compatibility tests (since rust-lang#142680). I was also able to remove a cfg for mips64. The remaining (tested) issues seem to be around how `f64` is handled there. cc @RalfJung r? tgross35

rustbot assigned workingjubilee Jun 18, 2025

rustbot added 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 Jun 18, 2025

rustbot assigned bjorn3 and unassigned workingjubilee Jun 18, 2025

tgross35 mentioned this pull request Jun 19, 2025

The sparc64, riscv64, loongarch64 extern "C" fn ABIs are all wrong when aligned/packed structs are involved #115609

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rustbot assigned WaffleLapkin and unassigned bjorn3 Jul 3, 2025

workingjubilee self-assigned this Jul 4, 2025

beetrees force-pushed the sparc64-float-struct-abi branch from 4eb3ce5 to 9e4a7bc Compare July 6, 2025 14:45

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beetrees force-pushed the sparc64-float-struct-abi branch from 9e4a7bc to b7b3ed7 Compare July 27, 2025 08:50

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folkertdev force-pushed the sparc64-float-struct-abi branch from 7515aca to 9129b31 Compare February 10, 2026 10:39

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Fix passing/returning structs with the 64-bit SPARC ABI

c9b5c93

Co-authored-by: beetrees <b@beetr.ee>

folkertdev force-pushed the sparc64-float-struct-abi branch from 8ebba60 to c9b5c93 Compare February 10, 2026 11:40

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Feb 10, 2026

Zalathar mentioned this pull request Feb 11, 2026

[EXPERIMENT] Rollup of 9 pull requests #152476

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Zalathar mentioned this pull request Feb 11, 2026

[EXPERIMENT] Rollup of 8 pull requests #152479

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Zalathar mentioned this pull request Feb 12, 2026

[EXPERIMENT] Rollup of 18 pull requests #152513

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jhpratt mentioned this pull request Feb 12, 2026

Rollup of 17 pull requests #152517

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rust-bors bot merged commit b1b6533 into rust-lang:main Feb 12, 2026
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rustbot added this to the 1.95.0 milestone Feb 12, 2026

tgross35 mentioned this pull request Feb 12, 2026

rustc on SPARC miscompiled after LLVM 22 update #151813

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RalfJung mentioned this pull request Feb 12, 2026

extern "C" fn on sparc64 targets does not respect repr(transparent) #115336

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folkertdev mentioned this pull request Feb 12, 2026

sparc64: enable abi compatibility test #152529

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