transmute: Mark edges by byte sets, not byte values
This leads to drastic performance improvements. For example, on the author's 2024 MacBook Pro, the time to convert the `Tree` representation of a `u64` to its equivalent DFA representation drops from ~8.5ms to ~1us, a reduction of ~8,500x. See `bench_dfa_from_tree`.
Similarly, the time to execute a transmutability query from `u64` to `u64` drops from ~35us to ~1.7us, a reduction of ~20x. See `bench_transmute`.
r? `@jswrenn`
make abi_unsupported_vector_types a hard error
Fixes https://github.com/rust-lang/rust/issues/116558 by completing the transition; see that issue for context. The lint was introduced with Rust 1.84 and this has been shown in cargo's future breakage reports since Rust 1.85, released 6 weeks ago, and so far we got 0 complaints by users. There's not even a backlink on the tracking issue. We did a [crater run](https://github.com/rust-lang/rust/pull/127731#issuecomment-2286736295) when the lint was originally added and found no breakage. So I don't think we need another crater run now, but I can do one if the team prefers that.
https://github.com/rust-lang/rust/issues/131800 is done, so for most current targets (in particular, all tier 1 and tier 2 targets) we have the information to implement this check (modulo the targets where we don't properly support SIMD vectors yet, see the sub-issues of https://github.com/rust-lang/rust/issues/116558). If a new target gets added in the future, it will default to reject all SIMD vector types until proper information is added, which is the default we want.
This will need approval by for `@rust-lang/lang.` Cc `@workingjubilee` `@veluca93`
try-job: test-various
try-job: armhf-gnu
try-job: dist-i586-gnu-i586-i686-musl
In the `Tree` and `Dfa` representations of a type's layout, store byte
ranges rather than needing to separately store each byte value. This
permits us to, for example, represent a `u8` using a single 0..=255 edge
in the DFA rather than using 256 separate edges.
This leads to drastic performance improvements. For example, on the
author's 2024 MacBook Pro, the time to convert the `Tree` representation
of a `u64` to its equivalent DFA representation drops from ~8.5ms to
~1us, a reduction of ~8,500x. See `bench_dfa_from_tree`.
Similarly, the time to execute a transmutability query from `u64` to
`u64` drops from ~35us to ~1.7us, a reduction of ~20x. See
`bench_transmute`.
Clippy subtree update
r? `@Manishearth`
Cargo.lock update due to the Clippy version bump and because Clippy moved from rinja (unmaintained) to askama.
Last sync was skipped due to the askama issue and me not getting to fixing this in time.
compiletest: Use the new non-libtest executor by default
The new executor was implemented in #139660, but required a manual opt-in. This PR activates the new executor by default, but leaves the old libtest-based executor in place (temporarily) to make reverting easier if something unexpectedly goes horribly wrong.
Currently the new executor can be explicitly disabled by passing the `-N` flag to compiletest (e.g. `./x test ui -- -N`), but eventually that flag will be removed, alongside the removal of the libtest dependency. The flag is mostly there to make manual comparative testing easier if something does go wrong.
As before, there *should* be no user-visible difference between the old executor and the new executor.
---
I didn't get much of a response to my [call for testing thread on Zulip](https://rust-lang.zulipchat.com/#narrow/channel/122651-general/topic/Call.20for.20testing.3A.20New.20test.20executor.20for.20compiletest/with/512452105), and the reports I did get (along with my own usage) indicate that there aren't any problems. So I think it's reasonable to move forward with making this the default, in the hopes of being able to remove the libtest dependency relatively soon.
When the libtest dependency is removed, it should be reasonable to build compiletest against pre-built stage0 std by default, even after the stage0 redesign. (Though we should probably have at least one CI job using in-tree stage1 std instead, to guard against the possibility of the `#![feature(internal_output_capture)]` API actually changing.)
Refactor git change detection in bootstrap
While working on https://github.com/rust-lang/rust/pull/138395, I finally found the courage to delve into the insides of git path change detection in bootstrap, which is used (amongst other things) to detect if we should rebuilt od download `[llvm|rustc|gcc]`. I found it a bit hard to understand, and given that this code was historically quite fragile, I thought that it would be better to rebuild it from scratch.
The previous approach had a bunch of limitations:
- It separated the computation of "are there local changes?" and "what upstream SHA should we use?" even though these two things are intertwined.
- It used hacks to work around what happens on CI.
- It had special cases for CI scattered throughout the codebase, rather than centralized in one place.
- It wasn't documented enough and didn't have tests for the git behavior.
The current approach should hopefully resolve all of that. I implemented a single entrypoint called `check_path_modifications` (naming bikeshed pending, half of the time I spend on this PR was thinking about names, as it's quite tricky here..) that explicitly receives a mode of operation (in CI or outside CI), and accordingly figures out that upstream SHA that we should use for downloading artifacts and it also figures out if there are any local changes. Users of this function can then use this unified output to implement `download-ci-X` and other functionality. Notably, this change detection no longer uses `git merge-base`, which makes it easier to use and doesn't require setting up remotes.
I also added a bunch of integration tests that literally spawn a git repository on disk and then check that the function can deal with various situations (PR CI, auto/try CI, local builds).
After I built this inner layer, I used it for downloading GCC, LLVM and rustc. The latter two (and especially rustc) were using the `last_modified_commit` function before, but in all cases but one this function was actually only used to check if there are any local changes, which was IMO confusing. The LLVM handling would deserve a bit of refactoring, but that's a larger change that can be done as a follow-up.
I hope that the implementation is now clear and easy to understand, so that in combination with the tests we can have more confidence that it does what we want. I tried to include a lot of documentation in the code, so I won't be repeating the actual implementation details here, if there are any questions, I'll add the answers to the documentation too :)
The new approach explicitly supports three scenarios:
- Running on PR CI, where we have one upstream bors parent commit and one PR merge commit made by GitHub.
- Running on try/auto CI, where we have one upstream bors parent commit and one PR merge commit made by bors.
- Running locally, where we assume that we have at least one upstream bors parent commit in our git history.
I removed the handling of upstreams on CI, as I think that it shouldn't be needed and I considered it to be a hack. However, it's possible that there are other use-cases that I haven't considered, so I want to ask around if people have other situations than the three use-cases described above. If there are other such use-cases, I would like to include them in the new centralized implementation and add them to the git test suite, rather than going back to the old ways :)
In particular, the code before relied on `git merge-base`, but I don't see why we can't just lookup the most recent bors commit and assume that is a merge commit that is also upstream? I might be running into Chesterton's Fence here :)
CC `@pietroalbini` To make sure that this won't break downstream users of Rust's CI.
Best reviewed commit by commit.
Companion PRs:
- For testing beta: https://github.com/rust-lang/rust/pull/138597
r? `@onur-ozkan`
Fixes: https://github.com/rust-lang/rust/issues/101907
try-job: x86_64-gnu-aux
try-job: aarch64-gnu
try-job: dist-x86_64-apple
Dynamic libraries on AIX have the ".a" extension. The c-link-to-rust-dylib
run-make test checks for the extension explicitly, so the extension for AIX
is also added to accommodate the test case on AIX.
Currently the new executor can be explicitly disabled by passing the `-N` flag
to compiletest (e.g. `./x test ui -- -N`), but eventually that flag will be
removed, alongside the removal of the libtest dependency.
`rc""` more clear error message
here is small fix that provides better error message when user is trying to use `rc""` the same way it was made for `rb""`
example of it's work
```rust
|
2 | rc"\n";
| ^^ unknown prefix
|
= note: prefixed identifiers and literals are reserved since Rust 2021
help: use `cr` for a raw C-string
|
2 - rc"\n";
2 + cr"\n";
|
```
**related issue**
fixes#140170
cc `@cyrgani` (issue author)
Validate extension in `PathBuf::add_extension`
The extension is validated in `PathBuf::set_extension`, but not `add_extension`. Fix that. Check for both `/` and `\` path separators on Windows, even when the path is verbatim, since this is logically like `PathBuf::push` which normalizes separators (i.e., keeping the current behavior).
`PathBuf::add_extension` is tracked in #127292.
r? `@ChrisDenton`
Use `is_lang_item` and `as_lang_item` instead of handrolling their logic
Various cleanups and deduplication. Most notably `if is_lang_item(foo, bar) {} else if is_lang_item...` chains are turned into matches. No behaviour changes intended beyond turning ICEs into fatal "lang item not found" errors
Clean: rename `open_braces` to `open_delimiters` in lexer and move `make_unclosed_delims_error` into `diagnostics.rs`.
Clean code prepared for resolving #138401. To avoid having too many extraneous changes in one PR, I cleaned up some of the naming and method placement in lexer in this PR.
1. For the make_unclosed_delims_error function defined in mod.rs is only used in lexer, so moved into lexer, which enhances encapsulation.
2. For open_braces in TokenTreeDiagInfo the naming is not canonical, as Brace refers to `{...} ` and this variable can store all kinds of different Delimiters. so I named it open_delimiters.
r? `@chenyukang`
Rollup of 8 pull requests
Successful merges:
- #139617 (Use posix_spawn on cygwin)
- #139921 (improve diagnostic for raw pointer field access with ->)
- #140031 (compiletest: Fix deadline bugs in new executor)
- #140072 (handle function alignment in miri)
- #140104 (Fix auto diff failing on inherent impl blocks)
- #140124 (Update books)
- #140144 (Handle another negated literal in `eat_token_lit`.)
- #140149 (test_nan: ensure the NAN contant is quiet)
r? `@ghost`
`@rustbot` modify labels: rollup
Handle another negated literal in `eat_token_lit`.
Extends the change from #139653, which was on expressions, to literals.
Fixes#140098.
r? ``@petrochenkov``
Update books
## rust-lang/nomicon
1 commits in 0c10c30cc54736c5c194ce98c50e2de84eeb6e79..c76a20f0d987145dcedf05c5c073ce8d91f2e82a
2025-04-15 20:54:57 UTC to 2025-04-15 20:54:57 UTC
- Say that dereferencing a pointer to a ZST is no longer undefined (rust-lang/nomicon#467)
## rust-lang/reference
7 commits in 3340922df189bddcbaad17dc3927d51a76bcd5ed..3bf3402aea982b876eb56c87da17b0685c6461d5
2025-04-18 13:44:45 UTC to 2025-04-17 17:27:01 UTC
- Use `cfg(false)` instead of `cfg(FALSE)` (rust-lang/reference#1763)
- Add `cfg(true)` and `cfg(false)` to conditional compilation (RFC 3695) (rust-lang/reference#1762)
- Refactor rendering with `RenderCtx` (rust-lang/reference#1796)
- attributes/codegen: update aarch64 features (rust-lang/reference#1791)
- Simplify GenericParams grammar (rust-lang/reference#1795)
- Add rule identifiers for the ABI chapter (rust-lang/reference#1793)
- Remove broken footnote links from grammar summary (rust-lang/reference#1794)
compiletest: Fix deadline bugs in new executor
The experimental new executor for compiletest (#139660) was found to have two major bugs in deadline handling for detecting slow tests:
- The comparison between `now` and test deadlines was reversed, causing no timeouts to ever be recognised.
- After fixing that bug, it was found that the existing code would issue timeouts for any test that had started more than 60 seconds ago, even if the test had finished long before its deadline was reached.
This PR fixes those bugs.
(The new executor is not yet enabled by default, so this PR has no immediate effect on contributors.)
---
I noted in https://github.com/rust-lang/rust/pull/139998#issuecomment-2815127046 that I hoped to have some unit tests to accompany these fixes. Unfortunately that turned out to be infeasible, because `DeadlineQueue` is tightly coupled to concrete `mpsc::Receiver` APIs (in addition to `Instant::now`), and trying to mock all of those would make the code much more complicated.
I did, however, add a few assertions that would have caught the failure to remove tests from the queue after their deadline.
r? jieyouxu
improve diagnostic for raw pointer field access with ->
This PR enhances the error messages emitted by the Rust compiler when users attempt to use the `->` operator for field access on raw pointers or when dereferencing is needed. The changes aim to provide clearer guidance, by suggesting the correct use of the `.` operator and explicit dereferencing.
**Before:**
```
help: `xs` is a raw pointer; try dereferencing it
|
LL | (*xs)->count += 1;
| ++ +
```
**Now:**
```
help: use `.` on a dereferenced raw pointer instead
|
LL - xs->count += 1;
LL + (*xs).count += 1;
|
```
I added extra clarification in the message. Since this error occurs in the parser, we can't be certain that the type is a raw pointer. That's why the message includes only a small note in brackets. (In contrast, the message above is emitted in HIR, where we *can* check whether it's a raw pointer.)
**Before:**
```
--> main.rs:11:11
|
11 | xs->count += 1;
| ^^
|
= help: the . operator will dereference the value if needed
```
**After:**
```
--> main.rs:11:11
|
11 | xs->count += 1;
| ^^
|
= help: the `.` operator will automatically dereference the value, except if the value is a raw pointer
```
