rust/library
bors c3605f8c80 Auto merge of #95897 - AzureMarker:feature/horizon-std, r=nagisa
STD support for the Nintendo 3DS

Rustc already supports compiling for the Nintendo 3DS using the `armv6k-nintendo-3ds` target (Tier 3). Until now though, only `core` and `alloc` were supported. This PR adds standard library support for the Nintendo 3DS. A notable exclusion is `std::thread` support, which will come in a follow-up PR as it requires more complicated changes.

This has been a joint effort by `@Meziu,` `@ian-h-chamberlain,` myself, and prior work by `@rust3ds` members.

### Background

The Nintendo 3DS (Horizon OS) is a mostly-UNIX looking system, with the caveat that it does not come with a full libc implementation out of the box. On the homebrew side (I'm not under NDA), the libc interface is partially implemented by the [devkitPro](https://devkitpro.org/wiki/devkitPro_pacman) toolchain and a user library like [`libctru`](https://github.com/devkitPro/libctru). This is important because there are [some possible legal barriers](https://github.com/rust-lang/rust/pull/88529#issuecomment-919938396) to linking directly to a library that uses the underlying platform APIs, since they might be considered a trade secret or under NDA.

To get around this, the standard library impl for the 3DS does not directly depend on any platform-level APIs. Instead, it expects standard libc functions to be linked in. The implementation of these libc functions is left to the user. Some functions are provided by the devkitPro toolchain, but in our testing, we used the following to fill in the other functions:
- [`libctru`] - provides more basic APIs, such as `nanosleep`. Linked in by way of [`ctru-sys`](https://github.com/Meziu/ctru-rs/tree/master/ctru-sys).
- [`pthread-3ds`](https://github.com/Meziu/pthread-3ds) - provides pthread APIs for `std::thread`. Implemented using [`libctru`].
- [`linker-fix-3ds`](https://github.com/Meziu/rust-linker-fix-3ds) - fulfills some other missing libc APIs. Implemented using [`libctru`].

For more details, see the `src/doc/rustc/src/platform-support/armv6k-nintendo-3ds.md` file added in this PR.

### Notes
We've already upstreamed changes to the [`libc`] crate to support this PR, as well as the upcoming threading PR. These changes have all been released as of 0.2.121, so we bump the crate version in this PR.
Edit: After some rebases, the version bump has already been merged so it doesn't appear in this PR.

A lot of the changes in this PR are straightforward, and follow in the footsteps of the ESP-IDF target: https://github.com/rust-lang/rust/pull/87666.

The 3DS does not support user space process spawning, so these APIs are unimplemented (similar to ESP-IDF).

[`libctru`]: https://github.com/devkitPro/libctru
[`libc`]: https://github.com/rust-lang/libc
2022-06-15 14:21:28 +00:00
..
alloc Rollup merge of #97869 - ssomers:btree_comments, r=Dylan-DPC 2022-06-14 10:35:29 +02:00
backtrace@4e5a3f7292 update libbacktrace 2022-05-20 09:30:26 +02:00
core Horizon OS STD support 2022-06-13 20:44:39 -07:00
panic_abort Fully stabilize NLL 2022-06-03 17:16:41 -04:00
panic_unwind Add underscores to rust_eh_personality arguments to mark them as unused 2022-06-09 09:50:26 -07:00
portable-simd Finish bumping stage0 2022-05-27 07:36:17 -04:00
proc_macro proc_macro: bypass RandomState to remove ASLR-like effects. 2022-06-13 07:59:44 +00:00
profiler_builtins Fully stabilize NLL 2022-06-03 17:16:41 -04:00
rtstartup
rustc-std-workspace-alloc Switch all libraries to the 2021 edition 2021-12-23 19:03:47 +08:00
rustc-std-workspace-core Switch all libraries to the 2021 edition 2021-12-23 19:03:47 +08:00
rustc-std-workspace-std Switch all libraries to the 2021 edition 2021-12-23 19:03:47 +08:00
std Auto merge of #95897 - AzureMarker:feature/horizon-std, r=nagisa 2022-06-15 14:21:28 +00:00
stdarch@28335054b1 Also allow unused macro rules in stdarch 2022-05-10 19:53:22 +02:00
test Fully stabilize NLL 2022-06-03 17:16:41 -04:00
unwind Stabilize the bundle native library modifier 2022-06-09 23:12:58 +04:00