Add support for environments with the FPU disabled #25
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src/lib.rs
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| @@ -2,6 +2,7 @@ | |||
| #![feature(c_unwind)] | |||
| #![feature(naked_functions)] | |||
| #![feature(non_exhaustive_omitted_patterns_lint)] | |||
| #![feature(cfg_target_abi)] | |||
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Is there a way to achieve this without additional nightly features? I'd like to avoid adding extra ones.
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I think it might be doable with target_feature, but I'm not sure. Will do some testing and find out.
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Never mind, the counterparts in target_feature are still unstable. The other option would be a cargo feature, but that feels weird. Your choice I guess.
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cfg_target_abi has been stabilized in the recent nightly (rust-lang/rust#119590), so we can now remove this #![feature]
src/unwinder/arch/aarch64.rs
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| Register(64..=95) => &mut self.fp[(reg.0 - 64) as usize], | ||
| _ => unimplemented!(), | ||
| } | ||
| } | ||
| } | ||
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| #[naked] | ||
| #[cfg(target_abi = "softfloat")] | ||
| pub extern "C-unwind" fn save_context(f: extern "C" fn(&mut Context, *mut ()), ptr: *mut ()) { | ||
| // No need to save caller-saved registers here. |
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Could you extract the asm using macro to avoid duplication? See riscv for example
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Yeah sure, will do.
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Please take another look of riscv code to avoid code duplication
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As I said in my comments, I fixed these as much as I could. I need your input on the first one. |
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Not sure how I closed this. Anyways, it's finally done. Sorry for the long wait. Hopefully this is what you envisioned. |
src/unwinder/arch/aarch64.rs
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| unsafe { | ||
| #[cfg(target_feature = "fp-armv8")] |
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AFAIK there is no such a target feature in aarch64 (at least on the Rust side):
$ rustc +nightly --print cfg --target aarch64-unknown-linux-gnu | grep target_feature
target_feature="neon"
$ rustc +nightly --print cfg --target aarch64-unknown-none | grep target_feature
target_feature="neon"
$ rustc +nightly --print cfg --target aarch64-unknown-none-softfloat | grep target_featurearm has it though: https://github.com/rust-lang/rust/blob/b5b13568fb5da4ac988bde370008d6134d3dfe6c/compiler/rustc_target/src/target_features.rs#L62
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Oh, weird—the error when I tried to use unwinding mentioned fp-armv8 explicitly. I'll fix that.
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To be more clear: when I tried to use the current unwinding master branch on aarch64-unknown-none-softfloat, I got a compile error saying that the registers d[n] require target feature fp-armv8. This is likely a diagnostic issue, and I'll see if I can reproduce it to send that over to rustc.
`fp-armv8` is an arm feature, not an aarch64 feature.
Currently, the crate causes an exception on systems where the FPU is off/nonexistent, because of this code segment that saves floating-point registers. This PR removes that floating-point saving on
-softfloattargets.