Don't try to evaluate const blocks during constant promotion
As of https://github.com/rust-lang/rust/pull/138499, trying to evaluate a const block in anything depended on by borrow-checking will result in a query cycle. Since that could happen in constant promotion, this PR adds a check for const blocks there to stop them from being evaluated.
Admittedly, this is a hack. See https://github.com/rust-lang/rust/issues/124328 for discussion of a more principled fix: removing cases like this from constant promotion altogether. To simplify the conditions under which promotion can occur, we probably shouldn't be implicitly promoting division or array indexing at all if possible. That would likely require a FCW and migration period, so I figure we may as well patch up the cycle now and simplify later.
Fixesrust-lang/rust#150464
I'll also lang-nominate this for visibility. I'm not sure there's much to discuss about this PR specifically, but it does represent a change in semantics. In Rust 1.87, the code below compiled. In Rust 1.88, it became a query cycle error. After this PR, it fails to borrow-check because the temporaries can no longer be promoted.
```rust
let (x, y, z);
// We only promote array indexing if the index is known to be in-bounds.
x = &([0][const { 0 }] & 0);
// We only promote integer division if the divisor is known not to be zero.
y = &(1 / const { 1 });
// Furthermore, if the divisor is `-1`, we only promote if the dividend is
// known not to be `int::MIN`.
z = &(const { 1 } / -1);
// The borrowed temporaries can't be promoted, so they were dropped at the ends
// of their respective statements.
(x, y, z);
```
std: move time implementations to `sys`
This is probably the most complex step of rust-lang/rust#117276 so far. Unfortunately, quite some of the internal time logic defined in the PAL is also used in other places like the filesystem code, so this isn't just a series of simple moves. I've left all that logic inside the PAL and only moved the actual `SystemTime`/`Instant` implementations.
While there are no functional changes, this PR also contains some slight code cleanups on Windows and Hermit, these are explained in the relevant commits.
For additional details see the individual commits, I've tried to make the messages as helpful as possible about what's going on.
compiletest: Add `CompilerKind` to distinguish between rustc and rustdoc
This PR slightly improves `TestCx::make_compile_args` by using `CompilerKind` to explicitly distinguish between rustc and rustdoc.
The resulting code could still use more attention, but I think this is a good incremental improvement.
There *should* (hopefully) be no change to overall compiletest behaviour.
Last on the list: Hermit. Since I anticipate that Hermit will share the UNIX
implementation in the future, I've left `Timespec` in the PAL to maintain a
similar structure. Also, I noticed that some public `Instant` methods were
redefined on the internal `Instant`. But the networking code can just use the
public `Instant`, so I've removed them.
WASI and TEEOS share the UNIX implementation. Since `Timespec` lives in the
PAL, this means that the `#[path]` imports of `unix/time.rs` still remain for
these two, unfortunately. Maybe we'll solve that in the future by always
including the UNIX PAL for these remotely UNIXy platforms. But that's a story
for another time...
Now for UNIX: `Timespec` is also used for things like futex or `Condvar`
timeouts, so it stays in the PAL along with some related definitions.
Everything else is `SystemTime`- and `Instant`-specific, and is thus moved to
`sys::time`.
Windows has a similar problem as UEFI: some internals are also used for
implementing other things. Thus I've left everything except for the actual
`Instant` and `SystemTime` implementations inside the PAL.
I've also taken the liberty of improving the code clarity a bit: there were a
number of manual `SystemTime` conversions (including one that masked an `i64`
to 32-bits before casting to `u32`, yikes) that now just call `from_intervals`.
Also, defining a `PerformanceCounterInstant` just to convert it to a regular
`Instant` immediately doesn't really make sense to me. I've thus changed the
`perf_counter` module to contain only free functions that wrap system
functionality. The actual conversion now happens in `Instant::now`.
Next up: UEFI. Unfortunately the time conversion internals are also required by
the filesystem code, so I've left them in the PAL. The `Instant` internals
however are only used for the `Instant` implementation, so I've moved them to
`sys` (for now).
On SOLID, the conversion functions are also used to implement helpers for
timeout conversion, so these stay in the PAL. The `Instant` (µITRON) and
`SystemTime` (SOLID-specific) implementations are merged into one. While it was
nice to have the µITRON parts in a separate module, there really isn't a need
for this currently, as there is no other µITRON target. Let's not worry about
this until such a target gets added...
Note that I've extracted the `get_tim` call from `Instant` into a wrapper
function in the PAL to avoid the need to make the inner `Instant` field public
for use in the PAL.
Now that the `unsupported` module exists, we can use it for VEX. VEX actually
supports `Instant` though, so the implementation-select needs to combine that
with the `unsupported` module.
Let's start with the easy ones:
* Motor just reexports its platform library
* The SGX code is just a trivial move
* Trusty, WASM and ZKVM are unsupported, this is very trivial. And we can get
rid of some `#[path = ...]`s, yay!
Use an associated type default for `Key::Cache`.
They currently aren't used because r-a didn't support them, but r-a support was recently merged in
https://github.com/rust-lang/rust-analyzer/pull/21243.
r? @Noratrieb
Reintroduce `QueryStackFrame` split.
I tried removing it in rust-lang/rust#151203, to replace it with something simpler. But a couple of fuzzing failures have come up and I don't have a clear picture on how to fix them. So I'm reverting the main part of rust-lang/rust#151203.
This commit also adds the two fuzzing tests.
Fixesrust-lang/rust#151226, rust-lang/rust#151358.
r? @oli-obk
slice/ascii: Optimize `eq_ignore_ascii_case` with auto-vectorization
- Refactor the current functionality into a helper function
- Use `as_chunks` to encourage auto-vectorization in the optimized chunk processing function
- Add a codegen test checking for vectorization and no panicking
- Add benches for `eq_ignore_ascii_case`
---
The optimized function is initially only enabled for x86_64 which has `sse2` as part of its baseline, but none of the code is platform specific. Other platforms with SIMD instructions may also benefit from this implementation.
Performance improvements only manifest for slices of 16 bytes or longer, so the optimized path is gated behind a length check for greater than or equal to 16.
Benchmarks - Cases below 16 bytes are unaffected, cases above all show sizeable improvements.
```
before:
str::eq_ignore_ascii_case::bench_large_str_eq 4942.30ns/iter +/- 48.20
str::eq_ignore_ascii_case::bench_medium_str_eq 632.01ns/iter +/- 16.87
str::eq_ignore_ascii_case::bench_str_17_bytes_eq 16.28ns/iter +/- 0.45
str::eq_ignore_ascii_case::bench_str_31_bytes_eq 35.23ns/iter +/- 2.28
str::eq_ignore_ascii_case::bench_str_of_8_bytes_eq 7.56ns/iter +/- 0.22
str::eq_ignore_ascii_case::bench_str_under_8_bytes_eq 2.64ns/iter +/- 0.06
after:
str::eq_ignore_ascii_case::bench_large_str_eq 611.63ns/iter +/- 28.29
str::eq_ignore_ascii_case::bench_medium_str_eq 77.10ns/iter +/- 19.76
str::eq_ignore_ascii_case::bench_str_17_bytes_eq 3.49ns/iter +/- 0.39
str::eq_ignore_ascii_case::bench_str_31_bytes_eq 3.50ns/iter +/- 0.27
str::eq_ignore_ascii_case::bench_str_of_8_bytes_eq 7.27ns/iter +/- 0.09
str::eq_ignore_ascii_case::bench_str_under_8_bytes_eq 2.60ns/iter +/- 0.05
```
Try to reduce rustdoc GUI tests flakyness
Should help with https://github.com/rust-lang/rust/issues/93784.
I replaced a use of `puppeteer.wait` function with a loop instead (like the rest of `browser-ui-test`).
r? @jieyouxu
Fix broken Xtensa installation link
### Location (URL)
https://doc.rust-lang.org/rustc/platform-support/xtensa.html
<img width="800" alt="image" src="https://github.com/user-attachments/assets/dbf1fea5-e65f-4bb2-beea-bf3267b12aff" />
### Summary
The Xtensa platform documentation currently links to an outdated Rust on ESP Book installation page that no longer exists.
The Rust on ESP Book has been reorganized, and the installation instructions previously referenced under `/book/installation/` are now located under the Getting Started section.
The link is updated to reference the current Toolchain Installation page, which contains the up-to-date instructions for building Xtensa targets.
lint: Use rustc_apfloat for `overflowing_literals`, add f16 and f128
Switch to parsing float literals for overflow checks using `rustc_apfloat` rather than host floats. This avoids small variations in platform support and makes it possible to start checking `f16` and `f128` as well.
Using APFloat matches what we try to do elsewhere to avoid platform inconsistencies.
remove `#[deprecated]` from unstable & internal `SipHasher13` and `24` types
These types are unstable and `doc(hidden)` (under the internal feature `hashmap_internals`). Deprecating them only adds noise (`#[allow(deprecated)]`) to all places where they are used, so this PR removes the deprecation attributes from them.
It also includes a few other small cleanups in separate commits, including one I overlooked in rust-lang/rust#151228.
Don't expose redundant information in `rustc_public`'s `LayoutShape`
Enum variant layouts don't need to store a full `LayoutShape`; just storing the fields offsets is enough and all other information can be inferred from the parent layout:
- size, align and ABI don't make much sense for individual variants and should generally be taken from the parent layout instead;
- variants always have `fields: FieldsShape::Arbitrary { .. }` and `variant: VariantShape::Single { .. }`.
In principle, the same refactor could be done on `rustc_abi::Layout` (see [this comment](https://github.com/rust-lang/rust/issues/113988#issuecomment-1646982272)) but I prefer starting with this smaller change first.
Adds two new Tier 3 targets - `aarch64v8r-unknown-none{,-softfloat}`
## New Tier 3 targets - `aarch64v8r-unknown-none` and `aarch64v8r-unknown-none-softfloat`
This PR adds two new Tier 3 targets - `aarch64v8r-unknown-none` and `aarch64v8r-unknown-none-softfloat`.
The existing `aarch64-unknown-none` target assumes Armv8.0-A as a baseline. However, Arm recently released the Arm Cortex-R82 processor which is the first to implement the Armv8-R AArch64 mode architecture. This architecture is similar to Armv8-A AArch64, however it has a different set of mandatory features, and is based off of Armv8.4. It is largely unrelated to the existing Armv8-R architecture target (`armv8r-none-eabihf`), which only operates in AArch32 mode.
The second `aarch64v8r-unknown-none-softfloat` target allows for possible Armv8-R AArch64 CPUs with no FPU, or for use-cases where FPU register stacking is not desired. As with the existing `aarch64-unknown-none` target we have coupled FPU support and Neon support together - there is no 'has FPU but does not have NEON' target proposed even though the architecture technically allows for it.
These targets are in support of firmware development on upcoming systems using the Arm Cortex-R82, particularly safety-critical firmware development. For now, it can be tested using the Arm's Armv8-R AArch64 Fixed Virtual Platform emulator, which we have used to test this target. We are also in the process of testing this target with the full compiler test suite as part of Ferrocene, in the same way we test `aarch64-unknown-none` to a safety-qualified standard. We have not identified any issues as yet, but if we do, we will send the fixes upstream to you.
## Ownership
This PR was developed by Ferrous Systems on behalf of Arm. Arm is the owner of these changes.
## Tier 3 Policy Notes
To cover off the Tier 3 requirements:
> A tier 3 target must have a designated developer or developers
Arm will maintain this target, and I have presumed the Embedded Devices Working Group will also take an interest, as they maintain the existing Arm bare-metal targets.
> Targets must use naming consistent with any existing targets
We prefix this target with `aarch64` because it generates A64 machine code (like `arm*` generates A32 and `thumb*` generates T32). In an ideal world I'd get to rename the existing target `aarch64v8a-unknown-none` but that's basically impossible at this point. You can assume `v6` for any `arm*` target where unspecified, and you can assume `v8a` for any `aarch64*` target where not specified.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
It works just like the existing AArch64 bare-metal target.
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
Noted.
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate.
It's a bare-metal target, offering libcore and liballoc.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible.
Done
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target.
AArch64 is a Tier 1 architecture, so I don't expect this target to cause any issues.
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
Noted.
> Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target.
It's AArch64 and so works with LLVM.
Update backtrace and windows-bindgen
Supersedes the backtrace bump in rust-lang/rust#151659
This is mostly just renaming `windows_targets` to `windows_link` but it needs to be done in tandem with the backtrace submodule update. The reason for doing this is that backtrace is both copy/pasted into std (via being a submodule) and published as an independent crate.
checksum-freshness: Fix invalid checksum calculation for binary files
Admittedly this is not the cleanest way to achieve this, but SourceMap is quite intertwined with source files being represented as Strings.
Tracking issue: https://github.com/rust-lang/cargo/issues/14136Closes: rust-lang/rust#151090
Stabilize ppc inline assembly
This stabilizes inline assembly for PowerPC and PowerPC64.
Corresponding reference PR: rust-lang/reference#2056
---
From the requirements of stabilization mentioned in https://github.com/rust-lang/rust/issues/93335
> Each architecture needs to be reviewed before stabilization:
> * It must have clobber_abi.
Done in https://github.com/rust-lang/rust/pull/146949.
> * It must be possible to clobber every register that is normally clobbered by a function call.
Done in https://github.com/rust-lang/rust/pull/131341
Similarly, `preserves_flags` is also implemented by this PR. Likewise, there is a non-code change to `preserve_flags` expectations that floating point and vector status and sticky bits are preserved. The reference manual update has more details.
> * Generally review that the exposed register classes make sense.
The followings can be used as input/output:
* reg (`r0`, `r[3-12]`, `r[14-r28]`): Any usable general-purpose register
* reg_nonzero (`r[3-12]`, `r[14-r28]`): General-purpose registers, but excludes `r0`. This is needed for instructions which define `r0` to be the value 0, such as register + immediate memory operations.
* reg/reg_nonzero `r29` on PowerPC64 targets.
* freg (`f[0-31]`): 64 bit floating pointer registers
The following are clobber-only:
* `ctr`, `lr`, `xer`: commonly clobbered special-purpose registers used in inline asm
* `cr` (`cr[0-7]`, `cr`): the condition register fields, or the entire condition register.
* `vreg` (`v[0-31]`): altivec/vmx register
* `vsreg` (`vs[0-63]`): vector-scalar register
* `spe_acc`: SPE accumulator, only available for PowerPC SPE targets.
The vreg and vsreg registers technically accept `#[repr(simd)]` types, but require the experimental `altivec` or `vsx` target features to be enabled. That work seems to be tracked here, rust-lang/rust#42743.
The following cannot be used as operands for inline asm:
* `r2`: the TOC pointer, required for most PIC code.
* `r13`: the TLS pointer
* `r[29]`: Reserved for internal usage by LLVM on PowerPC
* `r[30]`: Reserved for internal usage by LLVM on PowerPC and PowerPC64
* `r31`: the frame pointer
* `vrsave`: this is effectively an unused special-purpose register.
The `preserves_flags` behavior is updated with the following behavior (Note, this is not enforceable today due to LLVM restrictions):
* All status and sticky bits of `fpscr`, `spefscr`, and `vscr` are preserved.
The following registers are unavailable:
* `mma[0-7]`: These are new "registers" available on Power10, they are 512b registers which overlay 4x vsx registers. If needed, users can mark such clobbers as vsN*4, vsN*4+1,...,vsN*4+3.
* `ap`: This is actually a pseudo-register in gcc/llvm.
* `mq`: This register is only available on Power1 and Power2, and is not supported by llvm.
---
cc @taiki-e
r? @Amanieu
@rustbot label +A-inline-assembly
Switch to parsing float literals for overflow checks using
`rustc_apfloat` rather than host floats. This avoids small variations in
platform support and makes it possible to start checking `f16` and
`f128` as well.
Using APFloat matches what we try to do elsewhere to avoid platform
inconsistencies.
I tried removing it in #151203, to replace it with something simpler.
But a couple of fuzzing failures have come up and I don't have a clear
picture on how to fix them. So I'm reverting the main part of #151203.
This commit also adds the two fuzzing tests.
Fixes#151226, #151358.
