Improve documentation when adding a new target
https://github.com/rust-lang/rust/pull/133631#issuecomment-2607877936 shows that it can be a bit difficult process-wise to add a new target.
I've added a bit of text to the docs, suggesting that users add the target defintion/spec first, and later work on `std` support.
I also found that we have two places where we document how to add a new target. I've linked these for now, but they should probably be merged somehow in the future.
`@rustbot` label A-docs
r? compiler
CC `@workingjubilee` who's worked a lot on target specs IIRC.
Rollup of 7 pull requests
Successful merges:
- #133631 (Support QNX 7.1 with `io-sock`+libstd and QNX 8.0 (`no_std` only))
- #134358 (compiler: Set `target_abi = "ilp32e"` on all riscv32e targets)
- #135812 (Fix GDB `OsString` provider on Windows )
- #135842 (TRPL: more backward-compatible Edition changes)
- #135946 (Remove extra whitespace from rustdoc breadcrumbs for copypasting)
- #135953 (ci.py: check the return code in `run-local`)
- #136019 (Add an `unchecked_div` alias to the `Div<NonZero<_>>` impls)
r? `@ghost`
`@rustbot` modify labels: rollup
Support QNX 7.1 with `io-sock`+libstd and QNX 8.0 (`no_std` only)
Changes of this pull request:
1. Refactor code for qnx nto targets to share more code in file `nto_qnx.rs`
1. Add support for an additional network stack on nto qnx 7.1.
QNX 7.1 supports two network stacks:
1. `io-pkt`, which is default
2. `io-sock`, which is optional on 7.1 but default in QNX 8.0
As one can see in the [io-sock migration notes](https://www.qnx.com/developers/docs/7.1/index.html#com.qnx.doc.neutrino.io_sock/topic/migrate_app.html), this changes the libc API in a way similar to e.g. linux-gnu vs. linux-musl.
This change adds a new target which has a different value for `target_env`, so that e.g. libc can distinguish between both APIs.
2. Add initial support for QNX 8.0, thanks to AkhilTThomas. As it turned out, the problem with forking many processes still exists in QNX 8.0. Because if this, we are now using it for any QNX version (i.e. not check for `target_env` anymore).
Update emscripten std tests
This disables a bunch of emscripten tests that test things emscripten doesn't support and re-enables a whole bunch of tests which now work just fine on emscripten.
Tested with `EMCC_CFLAGS="-s MAXIMUM_MEMORY=2GB" ./x.py test library/ --target wasm32-unknown-emscripten`.
fix(libtest): Deprecate '--logfile'
rust-lang/testing-devex-team#9 proposed changing the behavior of `--logfile`. The given reasons were:
(1) Bazel can't programmatically process stdout. This seems like a limitation in Bazel and we recommend focusing on that. If we look at the wider Rust ecosystem, Rustc and Cargo don't support any such mechanism and the Cargo team rejected having one. Expecting this in libtest when its not supported elsewhere seems too specialized.
(2) Tests that leak out non-programmatic output that intermixes with programmatic output. We acknowledge this is a problem to be evaluated but we need to make sure we are stepping back and gathering requirements, rather than assuming `--logfile` will fit the needs.
Independent of the motive, regarding using or changing `--logfile`
(1) Most ways to do it would be a breaking change, like if we respect any stable `--format`. As suggested above, we could specialize this to new `--format` values but that would be confusing for some values to apply but not others.
(2) Other ways of solving this add new features to lib`test` when we are instead wanting to limit the feature set it has to minimize the compatibility surface that has to be maintained and the burden it would put on third party harnesses which are a focus area. Examples include `--format compact` or a `--log-format` flag
(3) The existence of `--logfile` dates back quite a ways (5cc050b265, rust-lang/rust#2127) and the history gives the
impression this more of slipped through rather than being an intended feature (see also
https://github.com/rust-lang/rust/pull/82350#discussion_r579732071). Deprecation would better match to how it has been treated. By deprecating this, we do not expect custom test harnesses (rust-lang/testing-devex-team#2) to implement this.
T-testing-devex held an FCP for deprecating in rust-lang/testing-devex-team#9 though according to
[RFC #3455](https://rust-lang.github.io/rfcs/3455-t-test.html), this is still subject to final approval from T-libs-api.
Closesrust-lang/testing-devex-team#9
Improve check-cfg expected names diagnostic
This PR improves the check-cfg `allow-same-level` test by ~~normalizing it's output and by~~ adding more context to the test.
It also filters the well known cfgs from the `expected names are` note, as to reduce the size of the diagnostic. Users can still find the full list on the [rustc book](https://doc.rust-lang.org/nightly/rustc/check-cfg.html#well-known-names-and-values), which is reinforced for Cargo users by adding a note in the Cargo check-cfg specific section.
Fixes https://github.com/rust-lang/rust/issues/135995
r? `@jieyouxu`
rust-lang/testing-devex-team#9 proposed changing the behavior of `--logfile`.
The given reasons were:
(1) Bazel can't programmatically process stdout. This seems like a
limitation in Bazel and we recommend focusing on that. If we look at
the wider Rust ecosystem, Rustc and Cargo don't support any such
mechanism and the Cargo team rejected having one. Expecting this in
libtest when its not supported elsewhere seems too specialized.
(2) Tests that leak out non-programmatic output that intermixes with
programmatic output. We acknowledge this is a problem to be evaluated
but we need to make sure we are stepping back and gathering
requirements, rather than assuming `--logfile` will fit the needs.
Independent of the motive, regarding using or changing `--logfile`
(1) Most ways to do it would be a breaking change, like if we respect
any stable `--format`. As suggested above, we could specialize this to
new `--format` values but that would be confusing for some values to
apply but not others.
(2) Other ways of solving this add new features to lib`test` when we are
instead wanting to limit the feature set it has to minimize the
compatibility surface that has to be maintained and the burden it would
put on third party harnesses which are a focus area. Examples include
`--format compact` or a `--log-format` flag
(3) The existence of `--logfile` dates back quite a ways
(5cc050b265,
rust-lang/rust#2127) and the history gives the
impression this more of slipped through rather than being an intended
feature (see also
https://github.com/rust-lang/rust/pull/82350#discussion_r579732071).
Deprecation would better match to how it has been treated.
By deprecating this, we do not expect custom test harnesses
(rust-lang/testing-devex-team#2) to implement this.
T-testing-devex held an FCP for deprecating in rust-lang/testing-devex-team#9
though according to
[RFC #3455](https://rust-lang.github.io/rfcs/3455-t-test.html),
this is still subject to final approval from T-libs-api.
QNX SDP 8.0 comes with newly renamed QNX OS 8.0, so update the page to talk about QNX, QNX Neutrino 7.0, QNX Neutrino 7.1 or QNX OS 8.0.
Also actually add a list of target triples.
Add NuttX support for AArch64 and ARMv7-A targets
This patch adds tier 3 support for AArch64 and ARMv7-A targets in NuttX, including:
- AArch64 target: aarch64-unknown-nuttx
- ARMv7-A target: armv7a-nuttx-eabi, armv7a-nuttx-eabihf
- Thumbv7-A target: thumbv7a-nuttx-eabi, thumbv7a-nuttx-eabihf
remove support for the (unstable) #[start] attribute
As explained by `@Noratrieb:`
`#[start]` should be deleted. It's nothing but an accidentally leaked implementation detail that's a not very useful mix between "portable" entrypoint logic and bad abstraction.
I think the way the stable user-facing entrypoint should work (and works today on stable) is pretty simple:
- `std`-using cross-platform programs should use `fn main()`. the compiler, together with `std`, will then ensure that code ends up at `main` (by having a platform-specific entrypoint that gets directed through `lang_start` in `std` to `main` - but that's just an implementation detail)
- `no_std` platform-specific programs should use `#![no_main]` and define their own platform-specific entrypoint symbol with `#[no_mangle]`, like `main`, `_start`, `WinMain` or `my_embedded_platform_wants_to_start_here`. most of them only support a single platform anyways, and need cfg for the different platform's ways of passing arguments or other things *anyways*
`#[start]` is in a super weird position of being neither of those two. It tries to pretend that it's cross-platform, but its signature is a total lie. Those arguments are just stubbed out to zero on ~~Windows~~ wasm, for example. It also only handles the platform-specific entrypoints for a few platforms that are supported by `std`, like Windows or Unix-likes. `my_embedded_platform_wants_to_start_here` can't use it, and neither could a libc-less Linux program.
So we have an attribute that only works in some cases anyways, that has a signature that's a total lie (and a signature that, as I might want to add, has changed recently, and that I definitely would not be comfortable giving *any* stability guarantees on), and where there's a pretty easy way to get things working without it in the first place.
Note that this feature has **not** been RFCed in the first place.
*This comment was posted [in May](https://github.com/rust-lang/rust/issues/29633#issuecomment-2088596042) and so far nobody spoke up in that issue with a usecase that would require keeping the attribute.*
Closes https://github.com/rust-lang/rust/issues/29633
try-job: x86_64-gnu-nopt
try-job: x86_64-msvc-1
try-job: x86_64-msvc-2
try-job: test-various
add m68k-unknown-none-elf target
r? `@workingjubilee`
The existing `m68k-unknown-linux-gnu` target builds `std` by default, requires atomics, and has a base cpu with an fpu. A smaller/more embedded target is desirable both to have a baseline target for the ISA, as well to make debugging easier for working on the llvm backend. Currently this target is using the `M68010` as the minimum CPU due, but as missing features are merged into the `M68k` llvm backend I am hoping to lower this further.
I have been able to build very small crates using a toolchain built against this target (together with a later version of `object`) using the configuration described in the target platform-support documentation, although getting anything of substantial complexity to build quickly hits errors in the llvm backend
Target: Add mips mti baremetal support
Do the same thing as gcc, which use the vendor `mti` to mark the toolchain as MIPS32r2 default.
We support both big endian and little endian flavor:
mips-mti-none-elf
mipsel-mti-none-elf
Add UWP (msvc) target support page
- Added Platform Support page for `x86_64-uwp-windows-msvc`, `i686-uwp-windows-msvc`, `thumbv7a-uwp-windows-msvc` and `aarch64-uwp-windows-msvc`
- Adding myself as a maintainer
- Removing the ticks for `thumbv7a-pc-windows-msvc` and `thumbv7a-uwp-windows-msvc` as they do not currently build due to #134565 and https://github.com/rust-lang/backtrace-rs/pull/685
- Fixed a few minor issues to let most of the UWP targets compile
- Happy new year to all!
r? jieyouxu
Do the same thing as gcc, which use the vendor `mti` to mark
the toolchain as MIPS32r2 default.
We support both big endian and little endian flavor:
mips-mti-none-elf
mipsel-mti-none-elf
Add illumos target documentation
Fixes https://github.com/rust-lang/rust/pull/130132#issuecomment-2339055221
`@jclulow` `@pfmooney` I'm adding you as requested.
The page is very barebones (as I do not know illumos well) and could use some improvements (for example in the "Cross-compilation toolchains and C code" section).
Feel free to suggest improvements (or rewrite it from scratch) if you find something.
Rollup of 4 pull requests
Successful merges:
- #134870 (Fix sentence fragment in `pin` module docs)
- #134884 (Fix typos)
- #134892 (Added codegen test for elidings bounds check when indexes are manually checked)
- #134894 (Document how to run the split Docker pipelines)
r? `@ghost`
`@rustbot` modify labels: rollup
Improve default target options for x86_64-unknown-linux-none
Without a standard library, we cannot unwind, so it should be panic=abort by default.
Additionally, it does not have std because while it is Linux, it cannot use libc, which std uses today for Linux.
Using PIE by default may be surprising to users, as shown in #134763, so I've documented it explicitly. I'm not sure if we want to count that as fixing the issue or not.
cc `@morr0ne,` as you added the target (and are the maintainer), and `@Noratrieb,` who reviewed that PR (:D).
