RFC: Use stable Rust #512
RFC: Use stable Rust #512
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The semantics of int-to-pointer casts under strict provenance has changed. Ideally, we would update our `From<usize> for Register` implementation to use the `sptr` crate, but `sptr` does not currently have a suitable license. There is a [PR](Gankra/sptr#14) to change that, but it hasn't gotten a response in 7 months, so I don't think we can use it. Instead, this copies the implementation of `core::ptr::invalid`. This also bumps our `thiserror` dependency, which forces Cargo to pick a newer version of `proc-macro2` that is compatible with recently nightly toolchains.
Only use nightly for miri.
| @@ -129,7 +117,7 @@ test: examples test-stable | |||
| LIBTOCK_PLATFORM=hifive1 cargo clippy $(EXCLUDE_STD) \ | |||
| --target=riscv32imac-unknown-none-elf --workspace | |||
| MIRIFLAGS="-Zmiri-strict-provenance -Zmiri-symbolic-alignment-check" \ | |||
| cargo miri test $(EXCLUDE_MIRI) --workspace | |||
| cargo +nightly miri test $(EXCLUDE_MIRI) --workspace | |||
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We need to pin to a particular nightly release, otherwise this will break randomly as new nightly toolchains come out.
It won't. |
I did some digging and found the reasoning here: rust-lang/rustup#3355. It seems the underlying issue is that because user-defined toolchain names exist, |
I'm not arguing with you, but these people built an entire programming language, they could figure out how to handle host-side testing needing a different compiler than a binary for an embedded system (if they wanted to). |
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Improved by #513 |
Opening this on top of #511 as an idea to switch to using stable rust. Since we don't have to chase specific nightly versions, it seems like a good idea to just use stable rust with a minimum version for specific features we want.
But, this toolchain selection seems very confusing because again rust seems like it doesn't really support cross-compiling. What we want are very separate ways to specify the toolchain for building for embedded targets from ways to specify the toolchain for running host-side tests. It remains perplexing to me that rust still doesn't really seem to take this seriously.
Specifically, I don't know how to tell cargo "use nightly, but use a nightly with miri available". Maybe it does this automatically since we are running a miri command? I don't know.