Move `std_detect` into stdlib
This PR moves the `std_detect` crate from `stdarch` to be a part of rust-lang/rust instead.
The first commit actually moves the whole directory from the stdarch Josh subtree, so that git blame history is kept intact. Then I had to make a few changes to appease `tidy`.
The most complex thing here is porting the tests. We can't have `std_detect` both in r-l/r and stdarch, because they could get desynchronized, so we have to perform the move more or less "atomically", which means that we also have to port all the existing `std_detect` tests from the `stdarch` repository.
The stdarch repo runs the following `std_detect` tests:
### Build
The `build-std-detect.sh` script (e2b6512aed/ci/build-std-detect.sh) builds `std_detect` using the nightly compiler for several targets. This will be subsumed by normal `x build library` on our Tier 1/2 targets. However, the stdarch repository also tests the following targets:
- aarch64-unknown-freebsd
- armv6-unknown-freebsd
- powerpc-unknown-freebsd
- powerpc64-unknown-freebsd
- aarch64-unknown-openbsd
Which we don't build/test on our CI currently. I think we have mostly two options here:
1) Ignore these targets
2) Create a special CI job that will build stage 1 rustc and then cross-compile std (or just the `std_detect` crate?) for these targets.
### Documentation
The `dox.sh` script (3fec5adcd5/ci/dox.sh) builds and documents `std_detect` for several targets. All of them are Tier 2/we have `dist-` jobs for them, so I think that we can just skip this and let our normal CI subsume it?
### Tests
The `run.sh` script (1b201cec2c/ci/run.sh) runs `cargo test` on `std_detect` with a bunch of variations of feature flags. This will be subsumed by `x test library` in our CI. The only problem is that `stdarch` runs these tests for a ludicrous number of targets:
```
- tuple: i686-unknown-linux-gnu
- tuple: x86_64-unknown-linux-gnu
- tuple: arm-unknown-linux-gnueabihf
- tuple: armv7-unknown-linux-gnueabihf
- tuple: aarch64-unknown-linux-gnu
- tuple: aarch64_be-unknown-linux-gnu
- tuple: riscv32gc-unknown-linux-gnu
- tuple: riscv64gc-unknown-linux-gnu
- tuple: powerpc-unknown-linux-gnu
- tuple: powerpc64-unknown-linux-gnu
- tuple: powerpc64le-unknown-linux-gnu
- tuple: s390x-unknown-linux-gnu
- tuple: i586-unknown-linux-gnu
- tuple: nvptx64-nvidia-cuda
- tuple: thumbv6m-none-eabi
- tuple: thumbv7m-none-eabi
- tuple: thumbv7em-none-eabi
- tuple: thumbv7em-none-eabihf
- tuple: loongarch64-unknown-linux-gnu
- tuple: wasm32-wasip1
- tuple: x86_64-apple-darwin
- tuple: x86_64-apple-ios-macabi
- tuple: aarch64-apple-darwin
- tuple: aarch64-apple-ios-macabi
- tuple: x86_64-pc-windows-msvc
- tuple: i686-pc-windows-msvc
- tuple: aarch64-pc-windows-msvc
- tuple: x86_64-pc-windows-gnu
- tuple: aarch64-unknown-linux-gnu
- tuple: aarch64_be-unknown-linux-gnu
- tuple: armv7-unknown-linux-gnueabihf
- tuple: loongarch64-unknown-linux-gnu
- tuple: powerpc-unknown-linux-gnu
- tuple: powerpc64-unknown-linux-gnu
- tuple: powerpc64le-unknown-linux-gnu
- tuple: riscv32gc-unknown-linux-gnu
- tuple: riscv64gc-unknown-linux-gnu
- tuple: s390x-unknown-linux-gnu
- tuple: x86_64-unknown-linux-gnu
- tuple: aarch64-apple-darwin
- tuple: aarch64-apple-ios-macabi
```
We definitely do not run *tests* for all of these targets on our CI.
# Outcome
We have decided to just subsume std_detect tests by our normal test suite for now, and not create a separate CI job. Therefore, this PR performs the following changes in target testing for `std_detect`:
The following T3 targets would go from "build" to "nothing":
```
aarch64-unknown-freebsd (T3)
armv6-unknown-freebsd (T3)
powerpc-unknown-freebsd (T3)
powerpc64-unknown-freebsd (T3)
aarch64-unknown-openbsd (T3)
```
The following T3 targets would go from "test" to "nothing":
```
aarch64_be-unknown-linux-gnu (T3)
riscv32gc-unknown-liux-gnu (T3)
```
The following T2 targets would go from "test" to "build":
```
arm-unknown-linux-gnueabihf (T2)
armv7-unknown-linux-gnueabihf (T2)
riscv64gc-unknown-linux-gnu (T2)
powerpc-unknown-linux-gnu (T2)
powerpc64-unknown-linux-gnu (T2)
powerpc64le-unknown-linux-gnu (T2)
s390x-unknown-linux-gnu (T2)
i586-unknown-linux-gnu (T2)
loongarch64-unknown-linux-gnu (T2)
wasm32-wasip1 (T2)
x86_64-apple-ios-macabi (T2)
aarch64-apple-ios-macabi (T2)
aarch64-pc-windows-msvc (T2)
armv7-unknown-linux-gnueabihf (T2)
loongarch64-unknown-linux-gnu (T2)
powerpc-unknown-linux-gnu (T2)
```
I have confirmed in https://github.com/rust-lang/stdarch/pull/1873 that the current version of this PR would pass stdarch's CI testsuite.
r? `@ghost`
try-job: armhf-gnu
try-job: arm-android
Rename `tests/{assembly,codegen}` into `tests/{assembly,codegen}-llvm` and ignore these testsuites if configured backend doesn't match
Follow-up of https://github.com/rust-lang/rust/pull/144125.
This PR changes `compiletest` so that `asm` tests are only run if they match the current codegen backend. To better reflect it, I renamed the `tests/ui/asm` folder into `tests/ui/asm-llvm`. Like that, we can add new asm tests for other backends if we want without needing to add extra code to `compiletest`.
Next step will be to use the new code annotations added in rust-lang/rust#144125 to ignore ui tests failing in cg_gcc until it's fixed on our side.
cc `@antoyo` `@oli-obk`
r? `@Kobzol`
flt2dec: replace for loop by iter_mut
Perf is explored in https://github.com/rust-lang/rust/issues/144118, which initially showed small losses, but then also showed significant gains. Both are real, but given the smallness of the losses, this seems a good change.
address clippy formatting nits
- int_log10.rs: change top level doc comments to outer
- collect.rs: remove empty line after doc comment
- clippy fix: markdown indentation for indented items after line break: a markdown list item continued over multiples lines, but those following lines which are part of the same item are not indented
- clippy fix: bound in one place: when there is a bound in angle brackets and another bound on the same variable in a where clause
Remove deprecated `MaybeUninit` slice methods
These were left in to make migration a bit easier, although they should be removed now since they were never stable.
fix Zip unsoundness (again)
Some history: The Zip TrustedRandomAccess specialization has tried to emulate the side-effects of the naive implementation for a long time, including backwards iteration. #82292 tried to fix unsoundness (#82291) in that side-effect-preservation code, but this introduced some panic-safety unsoundness (#86443), but the fix#86452 didn't fix it for nested Zip iterators (#137255).
Rather than piling yet another fix ontop of this heap of fixes this PR reduces the number of cases in which side-effects will be preserved; the necessary API guarantee change was approved in #83791 but we haven't made use of that so far.
fixes#137255
This alias was added in 9897bfb8a ("Fix memset arguments for MSP430
target"), which predates `core::ffi`. Now that it exists we can just use
`core::ffi::c_int`.
According to
https://discourse.llvm.org/t/rfc-volatile-access-to-non-dereferenceable-memory-may-be-well-defined/86303/4,
LLVM allows volatile operations on null and handles it correctly. This
should be allowed in Rust as well, because I/O memory may be hard-coded
to address 0 in some cases, like the AVR chip ATtiny1626.
A test case that ensured a failure when passing null to volatile was
removed, since it's now valid.
Due to the addition of `maybe_is_aligned` to `ub_checks`,
`maybe_is_aligned_and_not_null` was refactored to use it.
docs: revise restrictions on volatile operations
A distinction between usage on Rust memory vs. non-Rust memory was
introduced. Documentation was reworded to explain what that means, and
make explicit that:
- No trapping can occur from volatile operations;
- On Rust memory, all safety rules must be respected;
- On Rust memory, the primary difference from regular access is that
volatile always involves a memory dereference;
- On Rust memory, the only data affected by an operation is the one
pointed to in the argument(s) of the function;
- On Rust memory, provenance follows the same rules as non-volatile
access;
- On non-Rust memory, any address known to not contain Rust memory is
valid (including 0 and usize::MAX);
- On non-Rust memory, no Rust memory may be affected (it is implicit
that any other non-Rust memory may be affected, though, even if not
referenced by the pointer). This should be relevant when, for example,
reading register A causes a flag to change in register B, or writing
to A causes B to change in some way. Everything affected mustn't be
inside an allocation.
- On non-Rust memory, provenance is irrelevant and a pointer with none
can be used in a valid way.
fix: don't lint null as UB for volatile
Also remove a now-unneeded `allow` line.
fix: additional wording nits
Make slice comparisons const
This needed a fix for `derive_const`, too, as it wasn't usable in libcore anymore as trait impls need const stability attributes. I think we can't use the same system as normal trait impls while `const_trait_impl` is still unstable.
r? ```@fee1-dead```
cc rust-lang/rust#143800
docs(alloc::fmt): Make type optional, instead of matching empty string
Think this is clearer.
Noticed as I was implementing [`tree-sitter-rust-format-args`](https://github.com/nik-rev/tree-sitter-rust-format-args), and attempting to match the empty string results in an error.
