ringbuf: Remove unused #[used] we weren't using
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This commit removes one more instance of the `#[used]` attribute in `ringbuf` that we don't actually need --- in the macro that generates `counted_ringbuf!`s when counters are enabled but the actual ringbuf isn't. I had somehow forgotten this in #2167, my bad!
mkeeter
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Jul 23, 2025
hawkw
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Aug 13, 2025
Currently, Hubris' Rust toolchain is pinned to `nightly-2024-09-17`, which is from 10 months ago. This is kind of unfortunate, especially because that nightly is too old to support the Rust 2024 edition, which means we cannot update our dependencies on any crates where the latest version is built with Rust 2024. Beyond just updating the toolchain, there were some noteworthy changes: - Naked functions are now stable (yay!), but the attribute changed to `#[unsafe(naked)]`. Inline assembly in naked functions must now use `core::arch::naked_asm!` rather than normal `asm!`. As far as I can tell, the only difference between this and regular `asm!` is that it does not support `options(noreturn)`, as I believe the `naked_asm!` block kind of implies at least some of the codegen differences for `noreturn`. - New warnings on creation of temporary shared references to mutable statics showed up in `stm32h7-update-server`, where we were using `[T]::as_ptr()` on zero-sized slices in mutable statics that were used to get linker-generated addresses. `[T]::as_ptr()` takes an `&self` receiver, so this was generating a temporary shared reference to the mutable static. I changed this to use `&raw const`, which takes the address of the static without creating a shared reference. - There was a substantial regression in flash and RAM usage on the new toolchain due to [a change in the behavior of the `#[used]` attribute][1] which revealed [an underlying issue where ringbufs were not zero initialized][2]. These issues were resolved separately in #2167, #2168, #2170, and oxidecomputer/idolatry#65. In addition, there were a variety of unremarkable linting changes, including slightly better dead code detection (which detected some new dead code), and some annoying clippy nonsense. Note that this branch requires oxidecomputer/idolatry#65, which updates `idol` to generate code that doesn't emit warnings with the new toolchain, and fixes some of the flash/RAM size regression in code generated by `idol`. Fixes #2165 [1]: #2165 (comment) [2]: #2165 (comment)
rusty1968
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Sep 15, 2025
This commit removes one more instance of the `#[used]` attribute in `ringbuf` that we don't actually need --- in the macro that generates `counted_ringbuf!`s when counters are enabled but the actual ringbuf isn't. I had somehow forgotten this in oxidecomputer#2167, my bad!
rusty1968
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to rusty1968/hubris
that referenced
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Sep 17, 2025
Currently, Hubris' Rust toolchain is pinned to `nightly-2024-09-17`, which is from 10 months ago. This is kind of unfortunate, especially because that nightly is too old to support the Rust 2024 edition, which means we cannot update our dependencies on any crates where the latest version is built with Rust 2024. Beyond just updating the toolchain, there were some noteworthy changes: - Naked functions are now stable (yay!), but the attribute changed to `#[unsafe(naked)]`. Inline assembly in naked functions must now use `core::arch::naked_asm!` rather than normal `asm!`. As far as I can tell, the only difference between this and regular `asm!` is that it does not support `options(noreturn)`, as I believe the `naked_asm!` block kind of implies at least some of the codegen differences for `noreturn`. - New warnings on creation of temporary shared references to mutable statics showed up in `stm32h7-update-server`, where we were using `[T]::as_ptr()` on zero-sized slices in mutable statics that were used to get linker-generated addresses. `[T]::as_ptr()` takes an `&self` receiver, so this was generating a temporary shared reference to the mutable static. I changed this to use `&raw const`, which takes the address of the static without creating a shared reference. - There was a substantial regression in flash and RAM usage on the new toolchain due to [a change in the behavior of the `#[used]` attribute][1] which revealed [an underlying issue where ringbufs were not zero initialized][2]. These issues were resolved separately in oxidecomputer#2167, oxidecomputer#2168, oxidecomputer#2170, and oxidecomputer/idolatry#65. In addition, there were a variety of unremarkable linting changes, including slightly better dead code detection (which detected some new dead code), and some annoying clippy nonsense. Note that this branch requires oxidecomputer/idolatry#65, which updates `idol` to generate code that doesn't emit warnings with the new toolchain, and fixes some of the flash/RAM size regression in code generated by `idol`. Fixes oxidecomputer#2165 [1]: oxidecomputer#2165 (comment) [2]: oxidecomputer#2165 (comment)
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This commit removes one more instance of the
#[used]attribute inringbufthat we don't actually need --- in the macro that generatescounted_ringbuf!s when counters are enabled but the actual ringbuf isn't. I had somehow forgotten this in #2167, my bad!