Ensure `ptr::read` gets all the same LLVM `load` metadata that dereferencing does
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`. Trying to narrow it down, it seems that was because `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
The root cause is that `ptr::read` is currently implemented via the *untyped* `copy_nonoverlapping`, and thus the `load` doesn't get any type-aware metadata: no `noundef`, no `!range`. This PR solves that by lowering `ptr::read(p)` to `copy *p` in MIR, for which the backends already do the right thing.
Fortuitiously, this also improves the IR we give to LLVM for things like `mem::replace`, and fixes a couple of long-standing bugs where `ptr::read` on `Copy` types was worse than `*`ing them.
Zulip conversation: <https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Move.20array.3A.3AIntoIter.20to.20ManuallyDrop/near/341189936>
cc `@erikdesjardins` `@JakobDegen` `@workingjubilee` `@the8472`
Fixes#106369Fixes#73258
Remove `identity_future` indirection
This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.
Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]`annotation.
Fixes https://github.com/rust-lang/rust/issues/104826.
Allow binary files to go through the `FileLoader`
I'd like for `include_bytes!` to go through the `FileLoader` in an out-of-tree `rustc_driver` wrapper, and I can't find a reason it's not already done. It seems like most folks providing a custom `FileLoader` would want this too, so I added it.
I can solve my problem in other ways if there's a strong reason not to do it, but it seems simple and harmless.
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`.
Turned out to be a more general problem as `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
This PR lowers `ptr::read(p)` to `copy *p` in MIR, which fortuitiously also improves the IR we give to LLVM for things like `mem::replace`.
Make `unused_allocation` lint against `Box::new` too
Previously it only linted against `box` syntax, which likely won't ever be stabilized, which is pretty useless. Even now I'm not sure if it's a meaningful lint, but it's at least something 🤷
This means that code like the following will be linted against:
```rust
Box::new([1, 2, 3]).len();
f(&Box::new(1)); // where f : &i32 -> ()
```
The lint works by checking if a `Box::new` (or `box`) expression has an a borrow adjustment, meaning that the code that first stores the box in a variable won't be linted against:
```rust
let boxed = Box::new([1, 2, 3]); // no lint
boxed.len();
```
This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.
Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]` annotation.
Add `round_ties_even` to `f32` and `f64`
Tracking issue: #96710
Redux of #82273. See also #55107
Adds a new method, `round_ties_even`, to `f32` and `f64`, that rounds the float to the nearest integer , rounding halfway cases to the number with an even least significant bit. Uses the `roundeven` LLVM intrinsic to do this.
Of the five IEEE 754 rounding modes, this is the only one that doesn't already have a round-to-integer function exposed by Rust (others are `round`, `floor`, `ceil`, and `trunc`). Ties-to-even is also the rounding mode used for int-to-float and float-to-float `as` casts, as well as float arithmentic operations. So not having an explicit rounding method for it seems like an oversight.
Bikeshed: this PR currently uses `round_ties_even` for the name of the method. But maybe `round_ties_to_even` is better, or `round_even`, or `round_to_even`?
Desugaring of drop and replace at MIR build
This commit desugars the drop and replace deriving from an
assignment at MIR build, avoiding the construction of the
`DropAndReplace` terminator (which will be removed in a following PR).
In order to retain the same error messages for replaces a new
`DesugaringKind::Replace` variant is introduced.
The changes in the borrowck are also useful for future work in moving drop elaboration
before borrowck, as no `DropAndReplace` would be present there anymore.
Notes on test diffs:
* `tests/ui/borrowck/issue-58776-borrowck-scans-children`: the assignment deriving from the desugaring kills the borrow.
* `tests/ui/async-await/async-fn-size-uninit-locals.rs`, `tests/mir-opt/issue_41110.test.ElaborateDrops.after.mir`, `tests/mir-opt/issue_41888.main.ElaborateDrops.after.mir`: drop elaboration generates (or reads from) a useless drop flag due to an issue with the dataflow analysis. Will be fixed independently by https://github.com/rust-lang/rust/pull/106430.
See https://github.com/rust-lang/rust/pull/104488 for more context
This commit desugars the drop and replace deriving from an
assignment at MIR build, avoiding the construction of the
DropAndReplace terminator (which will be removed in a followign PR)
In order to retain the same error messages for replaces a new
DesugaringKind::Replace variant is introduced.
Remove `from` lang item
It was probably a leftover from the old `?` desugaring but anyways, it's unused now except for clippy, which can just use a diagnostics item.
Implement partial support for non-lifetime binders
This implements support for non-lifetime binders. It's pretty useless currently, but I wanted to put this up so the implementation can be discussed.
Specifically, this piggybacks off of the late-bound lifetime collection code in `rustc_hir_typeck::collect::lifetimes`. This seems like a necessary step given the fact we don't resolve late-bound regions until this point, and binders are sometimes merged.
Q: I'm not sure if I should go along this route, or try to modify the earlier nameres code to compute the right bound var indices for type and const binders eagerly... If so, I'll need to rename all these queries to something more appropriate (I've done this for `resolve_lifetime::Region` -> `resolve_lifetime::ResolvedArg`)
cc rust-lang/types-team#81
r? `@ghost`
Use associated items of `char` instead of freestanding items in `core::char`
The associated functions and constants on `char` have been stable since 1.52 and the freestanding items have soft-deprecated since 1.62 (https://github.com/rust-lang/rust/pull/95566). This PR ~~marks them as "deprecated in future", similar to the integer and floating point modules (`core::{i32, f32}` etc)~~ replaces all uses of `core::char::*` with `char::*` to prepare for future deprecation of `core::char::*`.
Enable new rlib in non stable cases
If bundled static library uses cfg (unstable) or whole-archive (wasn't supported) bundled libs are packed even without packed_bundled_libs.
r? `@petrochenkov`
Rename `PointerSized` to `PointerLike`
The old name was unnecessarily vague. This PR renames a nightly language feature that I added, so I don't think it needs any additional approval, though anyone can feel free to speak up if you dislike the rename.
It's still unsatisfying that we don't the user which of {size, alignment} is wrong, but this trait really is just a stepping stone for a more generalized mechanism to create `dyn*`, just meant for nightly testing, so I don't think it really deserves additional diagnostic machinery for now.
Fixes#107696, cc ``@RalfJung``
r? ``@eholk``
Move format_args!() into AST (and expand it during AST lowering)
Implements https://github.com/rust-lang/compiler-team/issues/541
This moves FormatArgs from rustc_builtin_macros to rustc_ast_lowering. For now, the end result is the same. But this allows for future changes to do smarter things with format_args!(). It also allows Clippy to directly access the ast::FormatArgs, making things a lot easier.
This change turns the format args types into lang items. The builtin macro used to refer to them by their path. After this change, the path is no longer relevant, making it easier to make changes in `core`.
This updates clippy to use the new language items, but this doesn't yet make clippy use the ast::FormatArgs structure that's now available. That should be done after this is merged.
Transform async `ResumeTy` in generator transform
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.
The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.
The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`.
Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors.
See <https://github.com/rust-lang/rust/issues/105501>.
The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
---
Fixes https://github.com/bjorn3/rustc_codegen_cranelift/issues/1330 CC `@bjorn3`
r? `@compiler-errors`
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.
The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.
The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.
Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <https://github.com/rust-lang/rust/issues/105501>.
The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
Various cleanups around pre-TyCtxt queries and functions
part of #105462
based on https://github.com/rust-lang/rust/pull/106776 (everything starting at [0e2b39f](0e2b39fd1f) is new in this PR)
r? `@petrochenkov`
I think this should be most of the uncontroversial part of #105462.
Remove duplicate sha-1 dependency
[`sha-1`](https://crates.io/crates/sha-1) is more or less a duplicate of [`sha1`](https://crates.io/crates/sha1). The `sha-1` is deprecated and no longer updated. This updates the dependencies to use the new name.
Some other dependencies that got updated as a consequence:
* The updated pest dependencies are currently only used by mdbook, and shouldn't have any issues.
* ucd-trie 0.1.3 to 0.1.5: No changelog, but looks like some tables were updated for new unicode versions: https://github.com/BurntSushi/ucd-generate/commits/master/ucd-trie. This is only used by pest (and thus mdbook).
* thiserror 1.33 to 1.38: Nothing significant in the notes at https://github.com/dtolnay/thiserror/releases.
