Improve assembly test for CMSE ABIs
Tracking issues: #75835#81391
This ensures the code-gen for these ABIs does not change silently. There is a small chance that this code-gen might change, however even GCC (https://godbolt.org/z/16arxab5x and https://godbolt.org/z/16arxab5x) generates almost the same assembly for these ABIs. I hope the notes in the comments should help fix the tests if it ever breaks.
improve compile errors for invalid ptr-to-ptr casts with trait objects
This is a follow-up to https://github.com/rust-lang/rust/pull/120248 to improve some of its error messages.
1. Make the borrowcheck error for "type annotation requires that x must outlive y" actually point at the type annotation, i.e. the type `T` in a `x as T` cast. This makes the error more consistent with other errors caused by type annotation in other places, such as
```text
error: lifetime may not live long enough
--> src/lib.rs:4:12
|
3 | fn bar(a: &i32) {
| - let's call the lifetime of this reference `'1`
4 | let b: &'static i32 = a;
| ^^^^^^^^^^^^ type annotation requires that `'1` must outlive `'static`
```
2. Don't say "cast" when we actually mean "coercion" and give borrowcheck errors from actual casts (which is currently just the check added in https://github.com/rust-lang/rust/pull/120248) a higher priority than ones from coercions. This can improve the errors for ptr-to-ptr cast between trait objects because they are are lowered as an upcast "unsizing" coercion if possible (which may be the identity upcast) followed by the actual cast.
3. Bring back the old "casting X as Y is invalid" message for type mismatch in the principals and reword the "vtable kinds may not match" message to more accurately describe the pointer metadata and not refer to "vtables" if the metadata is unknown.
fixes https://github.com/rust-lang/rust/issues/130030
r? `@WaffleLapkin` but feel free to reassign
This changes the remaining span for the cast, because the new `Cast`
category has a higher priority (lower `Ord`) than the old `Coercion`
category, so we no longer report the region error for the "unsizing"
coercion from `*const Trait` to itself.
Add `optimize_for_size` variants for stable and unstable sort as well as select_nth_unstable
- Stable sort uses a simple merge-sort that re-uses the existing - rather gnarly - merge function.
- Unstable sort jumps directly to the branchless heapsort fallback.
- select_nth_unstable jumps directly to the median_of_medians fallback, which is augmented with a custom tiny smallsort and partition impl.
Some code is duplicated but de-duplication would bring it's own problems. For example `swap_if_less` is critical for performance, if the sorting networks don't inline it perf drops drastically, however `#[inline(always)]` is also a poor fit, if the provided comparison function is huge, it gives the compiler an out to only instantiate `swap_if_less` once and call it. Another aspect that would suffer when making `swap_if_less` pub, is having to cfg out dozens of functions in in smallsort module.
Part of https://github.com/rust-lang/rust/issues/125612
r? `@Kobzol`
Revert "Apply EarlyOtherwiseBranch to scalar value #129047"
This reverts PR #129047, commit a772336fb3, reversing changes made to 702987f75b.
cc `@DianQK` and `@cjgillot` as the PR author and reviewer of #129047 respectively.
It seems [Apply EarlyOtherwiseBranch to scalar value #129047](https://github.com/rust-lang/rust/pull/129047) may have lead to several nightly regressions:
- https://github.com/rust-lang/rust/issues/130769
- https://github.com/rust-lang/rust/issues/130774
- https://github.com/rust-lang/rust/issues/130771
Example test that would ICE with changes in #129047 (this test is included in this PR):
```rs
//@ compile-flags: -C opt-level=3
//@ check-pass
use std::task::Poll;
pub fn poll(val: Poll<Result<Option<Vec<u8>>, u8>>) {
match val {
Poll::Ready(Ok(Some(_trailers))) => {}
Poll::Ready(Err(_err)) => {}
Poll::Ready(Ok(None)) => {}
Poll::Pending => {}
}
}
```
Since this is a mir-opt ICE that seems to quite easy to trigger with real-world crates being affected, let's revert for now and reland the mir-opt after these are fixed.
llvm: replace some deprecated functions
`LLVMMDStringInContext` and `LLVMMDNodeInContext` are deprecated, replace them with `LLVMMDStringInContext2` and `LLVMMDNodeInContext2`.
Also replace `Value` with `Metadata` in some function signatures for better consistency.
Mark `make_ascii_uppercase` and `make_ascii_lowercase` in `[u8]` and `str` as const.
Relevant tracking issue: #130698
This PR extends #130697 and #130713 to the similar methods in byte slices (`[u8]`) and string slices (`str`).
For the `str` methods, this simply requires adding the `const` specifier to the function signatures. The `[u8]` methods, however, require (at least a temporary) reimplementation due to the use of iterators and `for` loops.
Revert "Add recursion limit to FFI safety lint"
It's not necessarily clear if warning when we hit the recursion limit is the right thing to do, first of all.
**More importantly**, this PR was implemented incorrectly in the first place; it was not decrementing the recursion limit when stepping out of a type, so it would trigger when a ctype has more than RECURSION_LIMIT fields *anywhere* in the type's set of recursively reachable fields.
Reverts #130598Reopens#130310Fixes#130757
Check vtable projections for validity in miri
Currently, miri does not catch when we transmute `dyn Trait<Assoc = A>` to `dyn Trait<Assoc = B>`. This PR implements such a check, and fixes https://github.com/rust-lang/miri/issues/3905.
To do this, we modify `GlobalAlloc::VTable` to contain the *whole* list of `PolyExistentialPredicate`, and then modify `check_vtable_for_type` to validate the `PolyExistentialProjection`s of the vtable, along with the principal trait that was already being validated.
cc ``@RalfJung``
r? ``@lcnr`` or types
I also tweaked the diagnostics a bit.
---
**Open question:** We don't validate the auto traits. You can transmute `dyn Foo` into `dyn Foo + Send`. Should we check that? We currently have a test that *exercises* this as not being UB:
6c6d210089/src/tools/miri/tests/pass/dyn-upcast.rs (L14-L20)
I'm not actually sure if we ever decided that's actually UB or not 🤔
We could perhaps still check that the underlying type of the object (i.e. the concrete type that was unsized) implements the auto traits, to catch UB like:
```rust
fn main() {
let x: &dyn Trait = &std::ptr::null_mut::<()>();
let _: &(dyn Trait + Send) = std::mem::transmute(x);
//~^ this vtable is not allocated for a type that is `Send`!
}
```
Skip query in get_parent_item when possible.
For HirIds with a non-zero item local id, `self.parent_owner_iter(hir_id).next()` just returns the same HirId with the item local id set to 0, but also does a query to retrieve the Node which is ignored here, which seems wasteful.
Rework `non_local_definitions` lint to only use a syntactic heuristic
This PR reworks the `non_local_definitions` lint to only use a syntactic heuristic, i.e. not use a type-system logic for whenever an `impl` is local or not.
Instead the new logic wanted by T-lang in https://github.com/rust-lang/rust/issues/126768#issuecomment-2192634762, which is to consider every paths in `Self` and `Trait` and to no longer use the type-system inference trick.
`@rustbot` labels +L-non_local_definitions
Fixes#126768
add unqualified_local_imports lint
This lint helps deal with https://github.com/rust-lang/rustfmt/issues/4709 by having the compiler detect imports of local items that are not syntactically distinguishable from imports from other cates. Making them syntactically distinguishable ensures rustfmt can consistently apply the desired import grouping.
Rollup of 7 pull requests
Successful merges:
- #129201 (std: implement the `random` feature (alternative version))
- #130536 (bootstrap: Set the dylib path when building books with rustdoc)
- #130551 (Fix `break_last_token`.)
- #130657 (Remove x86_64-fuchsia and aarch64-fuchsia target aliases)
- #130721 (Add more test cases for block-no-opening-brace)
- #130736 (Add rustfmt 2024 reformatting to git blame ignore)
- #130746 (readd `@tgross35` and `@joboet` to the review rotation)
r? `@ghost`
`@rustbot` modify labels: rollup
Add rustfmt 2024 reformatting to git blame ignore
https://github.com/rust-lang/rust/pull/130724 essentially reformatted the world, so we should add it to the git blame ignore list.
Tested with `git blame compiler/rustc_abi/src/lib.rs -L1137,1146`. I first thought that I have to ignore the merge commit, but it seems like the actual commit that did the reformatting should be ignored instead.
r? ``@compiler-errors``
Fix `break_last_token`.
It currently doesn't handle the three-char tokens `>>=` and `<<=` correctly. These can be broken twice, resulting in three individual tokens. This is a latent bug that currently doesn't cause any problems, but does cause problems for #124141, because that PR increases the usage of lazy token streams.
r? `@petrochenkov`
bootstrap: Set the dylib path when building books with rustdoc
The library path is needed when the toolchain has been configured with
`[rust] rpath = false`. Otherwise, building the reference book will get
an error when it tries to run rustdoc, like:
rustdoc: error while loading shared libraries: librustc_driver-2ec457c3b8826b72.so
std: implement the `random` feature (alternative version)
Implements the ACP rust-lang/libs-team#393.
This PR is an alternative version of #129120 that replaces `getentropy` with `CCRandomGenerateBytes` (on macOS) and `arc4random_buf` (other BSDs), since that function is not suited for generating large amounts of data and should only be used to seed other CPRNGs. `CCRandomGenerateBytes`/`arc4random_buf` on the other hand is (on modern platforms) just as secure and uses its own, very strong CPRNG (ChaCha20 on the BSDs, AES on macOS) periodically seeded with `getentropy`.
Subtree sync for rustc_codegen_cranelift
The main highlight this time is a fix for a miscompilation of RwLock on macOS. Also a Cranelift update and a couple of extra vendor intrinsics on arm64.
r? `@ghost`
`@rustbot` label +A-codegen +A-cranelift +T-compiler
