WIP: Stable rust support #19
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The `extern "c-unwind"` ABI was stabilized in 1.71: https://blog.rust-lang.org/2023/07/13/Rust-1.71.0.html#c-unwind-abi There is still a nightly feature flag for this which covers the rest of that feature, that being the guarantee that unwinding out of an `extern "C"` function safely aborts. But this crate does not need that, so it's fine to remove the feature flag.
…` crate instead. That crate provides an implementation of naked functions using `global_asm!` that works on stable. It has a couple of limitations, which means a few changes to the code are required to make it work: - The naked functions have to be `unsafe`, which `save_context` wasn't. I marked it unsafe and from looking at it that looks like the right idea to me anyway. After all, it takes a raw pointer and will write to it. - The proc macro does not work well with interior `#[cfg]` attrs, so I had to put those on the entire items. This duplicates the functions signature and admittedly makes the code slightly uglier. - Since `global_asm` doesn't support options(noreturn), I had to delete it. This could be a slight pessimization for codegen.
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The c_unwind shouldn't be removed until the final c_unwind stabilisation completes. One issue with the naked function macro is that it will export additional symbols, where built-in naked function will not. |
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This is my attempt at making this crate (at least with default features) work on stable rust.
Mostly just putting this up to see what you think, so it's a draft PR for now.
It adds a proc macro dependency and makes the code uglier, so I understand if you think this is not worth the trouble.