- use correct code block markers
- add missing title
- rustfmt can now use edition setting in its config
... and this is set in Rust repo
- reduce visual noise
- needless repetition
- convention is to start sentence with upper case
- sembr
- whitespace
- semi-heading not adding much value
- fix grammar
1. added two new parts: Bootstrapping and Supporting Infrastructure;
2. touched up names of pre-existing parts, to match actual names in sidebar;
3. syntactic nits (start description of Analysis with a capital letter); and
4. make numbered list use only 1.
Co-authored-by: Tshepang Mbambo <tshepang@gmail.com>
Add `*_value` methods to proc_macro lib
This is the (re-)implementation of https://github.com/rust-lang/libs-team/issues/459.
It allows to get the actual value (unescaped) of the different string literals.
It was originally done in https://github.com/rust-lang/rust/pull/136355 but it broke the artifacts build so we decided to move the crate to crates.io to go around this limitation.
Part of https://github.com/rust-lang/rust/issues/136652.
Considering this is a copy-paste of the originally approved PR, no need to go through the whole process again. \o/
r? `@Urgau`
Only build `rust_test_helpers` for `{incremental,ui}` test suites
Only build `rust_test_helpers` for `{incremental,ui}` test suites.
Context: Trying to see what test suites actually need `rust_test_helpers`, because this was causing unnecessary local failures when trying to run `./x test tests/run-make --target=wasm32-unknown-unknown` when `run-make` tests don't need `rust_test_helpers` at all.
r? `@ghost`
try-job: armhf-gnu
try-job: test-various
try-job: x86_64-apple-1
try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: i686-msvc-1
try-job: x86_64-mingw-1
try-job: i686-mingw-1
tidy: Fix paths to `coretests` and `alloctests`
Following `#135937` and `#136642`, tests for core and alloc are in coretests and alloctests. Fix tidy to lint for the new paths. Also, update comments referring to the old locations.
Some context for changes which don't match that pattern:
- `library/std/src/thread/local/dynamic_tests.rs` and `library/std/src/sync/mpsc/sync_tests.rs` were moved under `library/std/tests/` in 332fb7e6f1 (Move std::thread_local unit tests to integration tests, 2025-01-17) and b8ae372e48 (Move std::sync unit tests to integration tests, 2025-01-17), respectively, so are no longer special cases.
- There never was a `library/core/tests/fmt.rs` file. That comment previously referred to `src/test/ui/ifmt.rs`, which was folded into `library/alloc/tests/fmt.rs` in 949c96660c (move format! interface tests, 2020-09-08).
Now, the only matches for `(alloc|core)/tests` are in `compiler/rustc_codegen_{cranelift,gcc}/patches`. I don't know why CI hasn't broken because those patches can't apply. Or maybe they somehow still can apply?
r? `@bjorn3`
Following `#135937` and `#136642`, tests for core and alloc are in
coretests and alloctests. Fix tidy to lint for the new paths. Also,
update comments referring to the old locations.
Some context for changes which don't match that pattern:
* library/std/src/thread/local/dynamic_tests.rs and
library/std/src/sync/mpsc/sync_tests.rs were moved under
library/std/tests/ in 332fb7e6f1 (Move std::thread_local unit tests
to integration tests, 2025-01-17) and b8ae372e48 (Move std::sync unit
tests to integration tests, 2025-01-17), respectively, so are no
longer special cases.
* There never was a library/core/tests/fmt.rs file. That comment
previously referred to src/test/ui/ifmt.rs, which was folded into
library/alloc/tests/fmt.rs in 949c96660c (move format! interface
tests, 2020-09-08).
Move `fd` into `std::sys`
Move platform definitions of `fd` into `std::sys`, as part of https://github.com/rust-lang/rust/issues/117276.
Unlike other modules directly under `std::sys`, this is only available on some platforms and I have not provided a fallback abstraction for unsupported platforms. That is similar to how `std::os::fd` is gated to only supported platforms.
Also, fix the `unsafe_op_in_unsafe_fn` lint, which was allowed for the Unix fd impl. Since macro expansions from `std::sys::pal::unix::weak` trigger this lint, fix it there too.
cc `@joboet,` `@ChrisDenton`
try-job: x86_64-gnu-aux
Rustdoc: typecheck settings.js
This makes the file fully typechecked with no instances of ``````@ts-expect-error`````` and no type casts.
r? `````@notriddle`````
Expose algebraic floating point intrinsics
# Problem
A stable Rust implementation of a simple dot product is 8x slower than C++ on modern x86-64 CPUs. The root cause is an inability to let the compiler reorder floating point operations for better vectorization.
See https://github.com/calder/dot-bench for benchmarks. Measurements below were performed on a i7-10875H.
### C++: 10us ✅
With Clang 18.1.3 and `-O2 -march=haswell`:
<table>
<tr>
<th>C++</th>
<th>Assembly</th>
</tr>
<tr>
<td>
<pre lang="cc">
float dot(float *a, float *b, size_t len) {
#pragma clang fp reassociate(on)
float sum = 0.0;
for (size_t i = 0; i < len; ++i) {
sum += a[i] * b[i];
}
return sum;
}
</pre>
</td>
<td>
<img src="https://github.com/user-attachments/assets/739573c0-380a-4d84-9fd9-141343ce7e68" />
</td>
</tr>
</table>
### Nightly Rust: 10us ✅
With rustc 1.86.0-nightly (8239a37f9) and `-C opt-level=3 -C target-feature=+avx2,+fma`:
<table>
<tr>
<th>Rust</th>
<th>Assembly</th>
</tr>
<tr>
<td>
<pre lang="rust">
fn dot(a: &[f32], b: &[f32]) -> f32 {
let mut sum = 0.0;
for i in 0..a.len() {
sum = fadd_algebraic(sum, fmul_algebraic(a[i], b[i]));
}
sum
}
</pre>
</td>
<td>
<img src="https://github.com/user-attachments/assets/9dcf953a-2cd7-42f3-bc34-7117de4c5fb9" />
</td>
</tr>
</table>
### Stable Rust: 84us ❌
With rustc 1.84.1 (e71f9a9a9) and `-C opt-level=3 -C target-feature=+avx2,+fma`:
<table>
<tr>
<th>Rust</th>
<th>Assembly</th>
</tr>
<tr>
<td>
<pre lang="rust">
fn dot(a: &[f32], b: &[f32]) -> f32 {
let mut sum = 0.0;
for i in 0..a.len() {
sum += a[i] * b[i];
}
sum
}
</pre>
</td>
<td>
<img src="https://github.com/user-attachments/assets/936a1f7e-33e4-4ff8-a732-c3cdfe068dca" />
</td>
</tr>
</table>
# Proposed Change
Add `core::intrinsics::f*_algebraic` wrappers to `f16`, `f32`, `f64`, and `f128` gated on a new `float_algebraic` feature.
# Alternatives Considered
https://github.com/rust-lang/rust/issues/21690 has a lot of good discussion of various options for supporting fast math in Rust, but is still open a decade later because any choice that opts in more than individual operations is ultimately contrary to Rust's design principles.
In the mean time, processors have evolved and we're leaving major performance on the table by not supporting vectorization. We shouldn't make users choose between an unstable compiler and an 8x performance hit.
# References
* https://github.com/rust-lang/rust/issues/21690
* https://github.com/rust-lang/libs-team/issues/532
* https://github.com/rust-lang/rust/issues/136469
* https://github.com/calder/dot-bench
* https://www.felixcloutier.com/x86/vfmadd132ps:vfmadd213ps:vfmadd231ps
try-job: x86_64-gnu-nopt
try-job: x86_64-gnu-aux
