Turn ProjectionElem::Subtype into CastKind::Subtype
I noticed that drop elaboration can't, in general, handle `ProjectionElem::SubType`. It creates a disjoint move path that overlaps with other move paths. (`Subslice` does too, and I'm working on a different PR to make that special case less fragile.) If its skipped and treated as the same move path as its parent then `MovePath.place` has multiple possible projections. (It would probably make sense to remove all `Subtype` projections for the canonical place but it doesn't make sense to have this special case for a problem that doesn't actually occur in real MIR.)
The only reason this doesn't break is that `Subtype` is always the sole projection of the local its applied to. For the same reason, it works fine as a `CastKind` so I figured that makes more sense than documenting and validating this hidden invariant.
cc rust-lang/rust#112651, rust-lang/rust#133258
r? Icnr (bc you've been the main person dealing with `Subtype` it looks like)
Much of the compiler calls functions on Align projected from AbiAlign.
AbiAlign impls Deref to its inner Align, so we can simplify these away.
Also, it will minimize disruption when AbiAlign is removed.
For now, preserve usages that might resolve to PartialOrd or PartialEq,
as those have odd inference.
Clean up `ty::Dynamic`
1. As a follow-up to PR rust-lang/rust#143036, remove `DynKind` entirely.
2. Inside HIR ty lowering, consolidate modules `dyn_compatibility` and `lint` into `dyn_trait`
* `dyn_compatibility` wasn't about dyn compatibility itself, it's about lowering trait object types
* `lint` contained dyn-Trait-specific diagnostics+lints only
interpret: copy_provenance: avoid large intermediate buffer for large repeat counts
Copying provenance worked in this odd way where the "preparation" phase (which is supposed to just extract the necessary information from the source range) already did all the work of repeating the result N times for the target range. This was needed to use the existing `insert_presorted` function on `SortedMap`.
This PR generalizes `insert_presorted` so that we can avoid this odd structure on copy-provenance, and maybe even improve performance.
interpret: fix overlapping aggregate initialization
This fixes the problem pointed out by ````@saethlin```` in https://github.com/rust-lang/rust/issues/146383#issuecomment-3273224645.
Also clarify when exactly current de-facto MIR semantics allow overlap of the LHS and RHS in an assignment.
Implement `#[rustc_align_static(N)]` on `static`s
Tracking issue: https://github.com/rust-lang/rust/issues/146177
```rust
#![feature(static_align)]
#[rustc_align_static(64)]
static SO_ALIGNED: u64 = 0;
```
We need a different attribute than `rustc_align` because unstable attributes are tied to their feature (we can't have two unstable features use the same unstable attribute). Otherwise this uses all of the same infrastructure as `#[rustc_align]`.
r? `@traviscross`
We need a different attribute than `rustc_align` because unstable attributes are
tied to their feature (we can't have two unstable features use the same
unstable attribute). Otherwise this uses all of the same infrastructure
as `#[rustc_align]`.
rename erase_regions to erase_and_anonymize_regions
I find it consistently confusing that `erase_regions` does more than replacing regions with `'erased`. it also makes some code look real goofy to be writing manual folders to erase regions with a comment saying "we cant use erase regions" :> or code that re-calls erase_regions on types with regions already erased just to anonymize all the bound regions.
r? lcnr
idk how i feel about the name being almost twice as long now
const-eval: disable pointer fragment support
This fixes https://github.com/rust-lang/rust/issues/146291 by disabling pointer fragment support for const-eval. I want to properly fix this eventually, but won't get to it in the next few weeks, so this is an emergency patch to prevent the buggy implementation from landing on stable. The beta cutoff is on Sep 12th so if this PR lands after that, we'll need a backport.
a more general version of https://github.com/rust-lang/rust/pull/146080.
after a bit of hacking in [`fluent.rs`](https://github.com/rust-lang/rust/blob/master/compiler/rustc_fluent_macro/src/fluent.rs), i discovered that i'm not the only one that is bad at following guidelines 😅. this pr lowercases the first letter of all the error messages in the codebase.
(i did not change things that are traditionally uppercased such as _MIR_, _ABI_ or _C_)
i think it's reasonable to run a `@bors try` so all the test suite is checked, as i cannot run some of the tests on my machine. i double checked (and replaced manually) all the old error messages, but better be safe than sorry.
in the future i will try to add a check in `x test tidy` that errors if an error message starts with an uppercase letter.
This was done in #145740 and #145947. It is causing problems for people
using r-a on anything that uses the rustc-dev rustup package, e.g. Miri,
clippy.
This repository has lots of submodules and subtrees and various
different projects are carved out of pieces of it. It seems like
`[workspace.dependencies]` will just be more trouble than it's worth.
Implement some more checks in `ptr_guaranteed_cmp`.
* Pointers with different residues modulo their allocations' least common alignment are never equal.
* Pointers to the same static allocation are equal if and only if they have the same offset.
* Pointers to different non-zero-sized static allocations are unequal if both point within their allocation, and not on opposite ends.
Tracking issue for `const_raw_ptr_comparison`: <https://github.com/rust-lang/rust/issues/53020>
This should not affect `is_null`, the only usage of this intrinsic on stable.
Closes https://github.com/rust-lang/rust/issues/144584
Pointers with different residues modulo their least common allocation alignment are never equal.
Pointers to the same static allocation are equal if and only if they have the same offset.
Strictly in-bounds (in-bounds and not one-past-the-end) pointers to different static allocations are always unequal.
A pointer cannot be equal to an integer if `ptr-int` cannot be null.
Also adds more tests for `ptr_guaranteed_cmp`.
Co-authored-by: Ralf Jung <post@ralfj.de>
Pretty print the name of an future from calling async closure
Fixes https://github.com/rust-lang/rust/issues/145606 by introducing a way to customize the path rendering of async closures' futures in the pretty printer API.
Miri: fix handling of in-place argument and return place handling
This fixes two separate bugs (in two separate commits):
- If the return place is `_local` and not `*ptr`, we didn't always properly protect it if there were other pointers pointing to that return place.
- If two in-place arguments are *the same* local variable, we didn't always detect that aliasing.
Add tracing to various miscellaneous functions
This PR adds tracing to:
- `ty.fn_sig()`. There is only one place where `fn_sig` is called for real within `rustc_const_eval`. There are three other places where it's called, but one is inside `ConstCx::fn_sig` (which does not seem to be used anywhere), another is under `if cfg!(debug_assertions)`, and the last is within `call_main` and thus gets called only once.
- the two possible things `find_mir_or_eval_fn` can do: "emulate_foreign_item" and "load_mir"
- all calls to `Const.eval()` within the Miri or the `rustc_const_eval` codebase.
- a separate commit also fixes the style of some tracing macros
Those are all quite long-lived operations, that in total make up for 6-7% of the total time spent in the program. I found out about them by looking for long periods of time that were previously not traced at all, using this SQL query in ui.perfetto.dev:
```sql
with ordered as (select s1.*, row_number() over (order by s1.ts) as rn from slices as s1 where s1.parent_id is null and s1.dur > 0 and s1.name != "frame" and s1.name != "step" and s1.name != "backtrace") select a.ts+a.dur as ts, b.ts-a.ts-a.dur as dur, a.id, a.track_id, a.category, a.depth, a.stack_id, a.parent_stack_id, a.parent_id, a.arg_set_id, a.thread_ts, a.thread_instruction_count, a.thread_instruction_delta, a.cat, a.slice_id, "empty" as name from ordered as a inner join ordered as b on a.rn=b.rn-1 /*where b.ts-a.ts-a.dur > 5000*/ order by b.ts-a.ts-a.dur desc
```
<details>
<summary>How the table was obtained</summary>
The above image was obtained in ui.perfetto.dev with the following SQL query after obtaining a trace file by running Miri on the following Rust code with `n=100`.
```sql
select "TOTAL PROGRAM DURATION" as name, count(*), max(ts + dur) as "sum(dur)", 100.0 as "%", null as "min(dur)", null as "max(dur)", null as "avg(dur)", null as "stddev(dur)" from slices union select "TOTAL OVER ALL SPANS (excluding events)" as name, count(*), sum(dur), cast(cast(sum(dur) as float) / (select max(ts + dur) from slices) * 1000 as int) / 10.0 as "%", min(dur), max(dur), cast(avg(dur) as int) as "avg(dur)", cast(sqrt(avg(dur*dur)-avg(dur)*avg(dur)) as int) as "stddev(dur)" from slices where parent_id is null and name != "frame" and name != "step" and dur > 0 union select name, count(*), sum(dur), cast(cast(sum(dur) as float) / (select max(ts + dur) from slices) * 1000 as int) / 10.0 as "%", min(dur), max(dur), cast(avg(dur) as int) as "avg(dur)", cast(sqrt(avg(dur*dur)-avg(dur)*avg(dur)) as int) as "stddev(dur)" from slices where parent_id is null and name != "frame" and name != "step" group by name order by sum(dur) desc, count(*) desc
```
```rust
fn main() {
let n: usize = std::env::args().nth(1).unwrap().parse().unwrap();
let mut v = (0..n).into_iter().collect::<Vec<_>>();
for i in &mut v {
*i += 1;
}
}
```
</details>
<img width="1689" height="317" alt="image" src="https://github.com/user-attachments/assets/ee2c81f5-d74a-4da5-b4b6-ab2770175b14" />
