`#[naked]`: report incompatible attributes
tracking issue: https://github.com/rust-lang/rust/issues/90957
this is a re-implementation of https://github.com/rust-lang/rust/pull/93809 by ``@bstrie`` which was closed 2 years ago due to inactivity.
This PR takes some of the final comments into account, specifically providing a little more context in error messages, and using an allow list to determine which attributes are compatible with `#[naked]`.
Notable attributes that are incompatible with `#[naked]` are:
* `#[inline]`
* `#[track_caller]`
* ~~`#[target_feature]`~~ (this is now allowed, see PR discussion)
* `#[test]`, `#[ignore]`, `#[should_panic]`
These attributes just directly conflict with what `#[naked]` should do.
Naked functions are still important for systems programming, embedded, and operating systems, so I'd like to move them forward.
- merge error codes
- use attribute name that is incompatible in error message
- add test for conditional incompatible attribute
- add `linkage` to the allowlist
`#[naked]`: use an allowlist for allowed options on `asm!` in naked functions
tracking issue: https://github.com/rust-lang/rust/issues/90957
this is mostly just a refactor, but using an allowlist (rather than a denylist) for which asm options are allowed in naked functions is a little safer.
These options are disallowed because naked functions are effectively global asm, but defined using inline asm.
The link pointed to a closed issue. Create a new one and point the link
to it.
Also add a help message to hint what change the user could make.
Fixes: https://github.com/rust-lang/rust/issues/127821
In <https://github.com/rust-lang/rust/pull/126922>, the
`binary_asm_labels` lint was added which flags labels such as `0:` and
`1:`. Before that change, LLVM was giving a confusing error on
x86/x86_64 because of an incorrect interpretation.
However, targets other than x86 and x86_64 never had the error message
and have not been a problem. This means that the lint was causing code
that previously worked to start failing (e.g. `compiler_builtins`),
rather than only providing a more clear messages where there has always
been an error.
Adjust the lint to only fire on x86 and x86_64 assembly to avoid this
regression.
add lint for inline asm labels that look like binary
fixes#94426
Due to a bug/feature in LLVM, labels composed of only the digits `0` and `1` can sometimes be confused with binary literals, even if a binary literal would not be valid in that position.
This PR adds detection for such labels and also as a drive-by change, adds a note to cases such as `asm!(include_str!("file"))` that the label that it found came from an expansion of a macro, it wasn't found in the source code.
I expect this PR to upset some people that were using labels `0:` or `1:` without issue because they never hit the case where LLVM got it wrong, but adding a heuristic to the lint to prevent this is not feasible - it would involve writing a whole assembly parser for every target that we have assembly support for.
[zulip discussion](https://rust-lang.zulipchat.com/#narrow/stream/238009-t-compiler.2Fmeetings/topic/.5Bweekly.5D.202024-06-20/near/445870628)
r? ``@estebank``
There are a few tests that depend on some target features **not** being
enabled by default, and usually they are correct with the default x86-64
target CPU. However, in downstream builds we have modified the default
to fit our distros -- `x86-64-v2` in RHEL 9 and `x86-64-v3` in RHEL 10
-- and the latter especially trips tests that expect not to have AVX.
These cases are few enough that we can just set them back explicitly.
Tweak value suggestions in `borrowck` and `hir_analysis`
Unify the output of `suggest_assign_value` and `ty_kind_suggestion`.
Ideally we'd make these a single function, but doing so would likely require modify the crate dependency tree.
Mention Register Size in `#[warn(asm_sub_register)]`
Fixes#121593
Displays the register size information obtained from `suggest_modifier()` and `default_modifier()`.
A bit of an inelegant fix but given that the error is created only
after call to `const_eval_poly()` and that the calling function
cannot propagate the error anywhere else, the error has to be
explicitly handled inside `mono_item.rs`.
* The WASI targets deal with the `main` symbol a bit differently than
native so some `codegen` and `assembly` tests have been ignored.
* All `ignore-emscripten` directives have been updated to
`ignore-wasm32` to be more clear that all wasm targets are ignored and
it's not just Emscripten.
* Most `ignore-wasm32-bare` directives are now gone.
* Some ignore directives for wasm were switched to `needs-unwind`
instead.
* Many `ignore-wasm32*` directives are removed as the tests work with
WASI as opposed to `wasm32-unknown-unknown`.
Implicitly enable evex512 if avx512 is enabled
LLVM 18 requires the evex512 feature to allow use of zmm registers. LLVM automatically sets it when using a generic CPU, but not when `-C target-cpu` is specified. This will result either in backend legalization crashes, or code unexpectedly using ymm instead of zmm registers.
For now, make sure that `avx512*` features imply `evex512`. Long term we'll probably have to deal with the AVX10 mess somehow.
Fixes https://github.com/rust-lang/rust/issues/121081.
r? `@Amanieu`
LLVM 18 requires the evex512 feature to allow use of zmm registers.
LLVM automatically sets it when using a generic CPU, but not when
`-C target-cpu` is specified. This will result either in backend
legalization crashes, or code unexpectedly using ymm instead of
zmm registers.
For now, make sure that `avx512*` features imply `evex512`. Long
term we'll probably have to deal with the AVX10 mess somehow.
