Unable to build on platforms without atomic types

[alistair23]

Some platforms (such as RV32IMC) don't have the atomic types. When trying to build radium for those platforms this error is seen:

error[E0432]: unresolved imports `core::sync::atomic::AtomicBool`, `core::sync::atomic::AtomicI16`, `core::sync::atomic::AtomicI32`, `core::sync::atomic::AtomicI8`, `core::sync::atomic::AtomicIsize`, `core::sync::atomic::AtomicPtr`, `core::sync::atomic::AtomicU16`, `core::sync::atomic::AtomicU32`, `core::sync::atomic::AtomicU8`, `core::sync::atomic::AtomicUsize`
  --> /home/alistair/.cargo/registry/src/github.jparrowsec.cn-1ecc6299db9ec823/radium-0.3.0/src/lib.rs:29:11
   |
29 |     self, AtomicBool, AtomicI16, AtomicI32, AtomicI8, AtomicIsize, AtomicPtr, AtomicU16, AtomicU32,
   |           ^^^^^^^^^^  ^^^^^^^^^  ^^^^^^^^^  ^^^^^^^^  ^^^^^^^^^^^  ^^^^^^^^^  ^^^^^^^^^  ^^^^^^^^^ no `AtomicU32` in `sync::atomic`
   |           |           |          |          |         |            |          |
   |           |           |          |          |         |            |          no `AtomicU16` in `sync::atomic`
   |           |           |          |          |         |            no `AtomicPtr` in `sync::atomic`
   |           |           |          |          |         no `AtomicIsize` in `sync::atomic`
   |           |           |          |          no `AtomicI8` in `sync::atomic`
   |           |           |          no `AtomicI32` in `sync::atomic`
   |           |           no `AtomicI16` in `sync::atomic`
   |           no `AtomicBool` in `sync::atomic`
30 |     AtomicU8, AtomicUsize, Ordering,
   |     ^^^^^^^^  ^^^^^^^^^^^ no `AtomicUsize` in `sync::atomic`
   |     |
   |     no `AtomicU8` in `sync::atomic`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0432`.
error: could not compile `radium`.

To learn more, run the command again with --verbose.
make: *** [Makefile:141: flash-opentitan] Error 101

Something like this: rust-embedded/heapless#123 should hopefully fix the problem.

[myrrlyn]

The WIP branch to resolve this is feature/3. I have just pushed commit 1fd54d1, which adds a build script to detect the target architecture and set our own equivalents of the Rust-internal cfg(target_has_atomic) gates.

Please patch your manifest to use

[dependencies.radium]
git = "https://github.com/mystor/radium
rev = "feature/3"

and test your project. The expected results are for radium to successfully compile, and for bitvec to fail.

You can sidestep the bitvec failure temporarily by setting

[dependencies.bitvec]
default-features = false

If these patches work, I will release a new radium that uses the build script, and a new bitvec that uses the new radium, and let you know when they are available.

Thank you for this issue.

[alistair23]

Hey, thanks so much for this. I just checked the feature/3 branch and it builds for riscv32imc. I haven't had a chance to test it in my project as it's a few dependency levels deep. This at least allows it to build so that's a great start.

[tarcieri]

@alistair23 you should be able to test it by adding:

[patch.crates-io]
radium = { git = "https://github.com/mystor/radium.git", branch = "feature/3" }

...directive in your toplevel Cargo.toml

[alistair23]

Ah awesome.

Radium builds, bitvec doesn't though:

error[E0277]: the trait bound `core::cell::Cell<u8>: radium::Radium<u8>` is not satisfied
   --> /home/alistair/.cargo/registry/src/github.jparrowsec.cn-1ecc6299db9ec823/bitvec-0.18.3/src/store.rs:128:8
    |
85  |   pub trait BitStore: seal::Sealed + Sized + Debug {
    |             -------- required by a bound in this
...
105 |           + Radium<<Self::Alias as BitStore>::Mem>;
    |             -------------------------------------- required by this bound in `store::BitStore`
...
128 |           impl BitStore for $t {
    |                ^^^^^^^^ the trait `radium::Radium<u8>` is not implemented for `core::cell::Cell<u8>`
...
179 | / bitstore!(
180 | |     u8 => atomic::AtomicU8,
181 | |     u16 => atomic::AtomicU16,
182 | |     u32 => atomic::AtomicU32,
183 | |     usize => atomic::AtomicUsize,
184 | | );
    | |__- in this macro invocation
    |
    = help: the following implementations were found:
              <core::cell::Cell<*mut T> as radium::Radium<*mut T>>
              <core::cell::Cell<bool> as radium::Radium<bool>>
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

[myrrlyn]

I forgot how our codegen macros worked, and accidentally disabled Radium production entirely. Pushed the fix.

[alistair23]

Perfect! It works now!

[myrrlyn]

mystor/4 is now merged, and published as radium 0.4, closing this issue. bitvec 0.19.1 is now published to depend on it.

[myrrlyn]

This is already covered by building with --no-default-features, as riscv32imc-unknown-none-elf does not have std, but you must not enable --features atomic on this target, or the compilation will fail. This is a problem that I will fix when the compiler makes it convenient.

[alistair23]

Thanks!