Skip to content

Fix .type directive syntax for ARM targets#168

Closed
walruscraft wants to merge 1 commit intosunfishcode:mainfrom
walruscraft:fix-arm-function-type-syntax
Closed

Fix .type directive syntax for ARM targets#168
walruscraft wants to merge 1 commit intosunfishcode:mainfrom
walruscraft:fix-arm-function-type-syntax

Conversation

@walruscraft
Copy link
Contributor

@walruscraft walruscraft commented Jan 11, 2026

ARM GNU assembler uses %function instead of @function for the .type directive. The @function syntax causes build failures on arm-unknown-linux-gnueabihf:

error: expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '%<type>' or "<type>"
 --> <inline asm>:2:15
  |
2 | .type _start, @function
  |               ^

This adds an ARM-specific variant of the naked_fn! macro that uses the correct syntax.

Tested with cargo build --target arm-unknown-linux-gnueabihf.

@walruscraft
Fix .type directive syntax for ARM targets
92400cc 
ARM GNU assembler uses %function instead of @function for the .type
directive. This was causing build failures on arm-unknown-linux-gnueabihf.
bjorn3
bjorn3 reviewed Jan 11, 2026
View reviewed changes
src/naked.rs
@@ -54,7 +54,10 @@ macro_rules! naked_fn {
/// `#[naked]` is nightly-only. We use it when we can, and fall back to
/// `global_asm` otherwise. This macro supports a limited subset of the
/// features of `#[naked]`.
Copy link
Contributor

@bjorn3 bjorn3 Jan 11, 2026

Choose a reason for hiding this comment

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

#[naked] is now available on stable.

@walruscraft
Copy link
Contributor Author

walruscraft commented Jan 12, 2026

Thanks for the pointer! Unfortunately the nightly feature forces the unwinding crate which conflicts with panic="abort" builds. The global_asm fallback path is still needed for minimal no_std binaries that don't want unwinding overhead.

@bjorn3
Copy link
Contributor

bjorn3 commented Jan 12, 2026

I don't mean that you should enable the nightly feature. Rather I think you can change origin to use #[naked] rather than global_asm!() even the nightly feature is disabled.

@walruscraft
Copy link
Contributor Author

walruscraft commented Jan 12, 2026

Ah, you're right - I was confusing the nightly feature with #[naked] itself. Makes sense that stable #[naked] would handle the platform-specific asm syntax internally, avoiding this whole %function vs @function mess.

Happy to look into refactoring naked_fn! to use #[naked] directly if that's the way to go. Want me to update this PR or open a fresh one?

@bjorn3
Copy link
Contributor

bjorn3 commented Jan 12, 2026

A new PR probably makes sense.

@walruscraft walruscraft mentioned this pull request Jan 12, 2026
Merged
@walruscraft
Copy link
Contributor Author

walruscraft commented Jan 12, 2026

Closing in favor of #169 which takes the cleaner approach of using stable #[naked] directly.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

1 more reviewer

@bjorn3 bjorn3 bjorn3 left review comments

Reviewers whose approvals may not affect merge requirements

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

2 participants

@walruscraft @bjorn3