Fix panic with closure inside array len
I was working on #15947 and found out that we panic on this test:
```
fn main() {
let x = [(); &(&'static: loop { |x| {}; }) as *const _ as usize]
}
```
This PR fixes the panic. Closures in array len are still broken, but closure in const eval is not stable anyway.
Avoid adding builtin functions to `symbols.o`
We found performance regressions in #113923. The problem seems to be that `--gc-sections` does not remove these symbols. I tested that lld removes these symbols, but ld and gold do not.
I found that `used` adds symbols to `symbols.o` at 3e202ead60/compiler/rustc_codegen_ssa/src/back/linker.rs (L1786-L1791).
The PR removes builtin functions.
Note that under LTO, ld still preserves these symbols. (lld will still remove them.)
The first commit also fixes#118559. But I think the second commit also makes sense.
compile-time evaluation: detect writes through immutable pointers
This has two motivations:
- it unblocks https://github.com/rust-lang/rust/pull/116745 (and therefore takes a big step towards `const_mut_refs` stabilization), because we can now detect if the memory that we find in `const` can be interned as "immutable"
- it would detect the UB that was uncovered in https://github.com/rust-lang/rust/pull/117905, which was caused by accidental stabilization of `copy` functions in `const` that can only be called with UB
When UB is detected, we emit a future-compat warn-by-default lint. This is not a breaking change, so completely in line with [the const-UB RFC](https://rust-lang.github.io/rfcs/3016-const-ub.html), meaning we don't need t-lang FCP here. I made the lint immediately show up for dependencies since it is nearly impossible to even trigger this lint without `const_mut_refs` -- the accidentally stabilized `copy` functions are the only way this can happen, so the crates that popped up in #117905 are the only causes of such UB (in the code that crater covers), and the three cases of UB that we know about have all been fixed in their respective crates already.
The way this is implemented is by making use of the fact that our interpreter is already generic over the notion of provenance. For CTFE we now use the new `CtfeProvenance` type which is conceptually an `AllocId` plus a boolean `immutable` flag (but packed for a more efficient representation). This means we can mark a pointer as immutable when it is created as a shared reference. The flag will be propagated to all pointers derived from this one. We can then check the immutable flag on each write to reject writes through immutable pointers.
I just hope perf works out.
Fix WideChar offsets calculation in `line-index`
Fix#15981. This PR addresses the issue with the WideChar's offset calculation, ensuring accurate line-specific positions during text analysis in the `lib/line-index` module.
## Changes Made
- Corrected the calculation for `WideChar` offsets, ensuring they reflect positions within respective lines.
- Added tests to verify the accuracy of `WideChar` offset calculations, and correct existing tests.
Re-enable `rustc_codegen_gcc` tests in CI
When #117947 dropped llvm-15 from CI, we neglected to copy #117313's changes to enable `rustc_codegen_gcc` testing to the new base llvm-16. This is now restored, as well as copying the setup to llvm-17 as well so we hopefully won't miss it next time.
In addition, due to case mismatch in `$extra_env` updates in `docker/run.sh`, I think it wasn't actually getting enabled before, but this should now be fixed. I also avoided the linker hack for `libgccjit.so` that was present before, because that's not needed if the version matches the base `gcc` used for linking.
r? GuillaumeGomez
Remove `#[rustc_host]`, use internal desugaring
Also removed a way for users to explicitly specify the host param since that isn't particularly useful. This should eliminate any pain with encoding attributes across crates and etc.
r? `@compiler-errors`
make ParamLoweringMode accessible
In `hir-ty`, the `TyLoweringContext` has functions `pub fn with_impl_trait_mode` and `pub fn with_type_param_mode`, which can be used to fine-tune certain lowering properties.
Each of these takes one enum (either `pub enum ImplTraitLoweringMode`, or `pub enum ParamLoweringMode`), which encodes the possible configuration options.
To then make this usable for other crates, `TyLoweringContext` and `ImplTraitLoweringMode` are exported. Unfortuntely, `ParamLoweringMode` is not. This means that while the method can be called, there are no useful values to call it with.
Presumably this is an oversight. It would be great if this was made actually public.
coverage: Be more strict about what counts as a "visible macro"
This is a follow-up to the workaround in #117827, and I believe it now properly fixes#117788.
The old code treats a span as having a “visible macro” if it is part of a macro-expansion, and its parent callsite's context is the same as the body span's context. But if the body span is itself part of an expansion, the macro in question might not actually be visible from the body span. That results in the macro name's length being meaningless as a span offset.
We now only consider spans whose parent callsite is the same as the source callsite, i.e. the parent has no parent.
---
I've also included some related cleanup for the code added by #117827. That code was more complicated than normal, because I wanted it to be easy to backport to stable/beta.
feat: Allow navigation targets to be duplicated when the focus range lies in the macro definition site
Basically if a name of an item originates from the macro definition we now point to that as well as the creating macro call.
Big diff because I also made `FileId`s field private due to some debugging I had to do (having a searchable constructor makes things easier).
Added shadowed hint for overlapping associated types
Previously, when you tried to set an associated type that is shadowed by an associated type in a subtrait, like this:
```rust
trait A {
type X;
}
trait B: A {
type X; // note: this is legal
}
impl<Y> Clone for Box<dyn B<X=Y, X=Y>> {
fn clone(&self) -> Self {
todo!()
}
}
you got a confusing error message, that says nothing about the shadowing:
error[E0719]: the value of the associated type `X` (from trait `B`) is already specified
--> test.rs:9:34
|
9 | impl<Y> Clone for Box<dyn B<X=Y, X=Y>> {
| --- ^^^ re-bound here
| |
| `X` bound here first
error[E0191]: the value of the associated type `X` (from trait `A`) must be specified
--> test.rs:9:27
|
2 | type X;
| ------ `X` defined here
...
9 | impl<Y> Clone for Box<dyn B<X=Y, X=Y>> {
| ^^^^^^^^^^^ help: specify the associated type: `B<X=Y, X=Y, X = Type>`
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0191, E0719.
For more information about an error, try `rustc --explain E0191`.
```
Now instead, the error shows that the associated type is shadowed, and suggests renaming as a potential fix.
```rust
error[E0719]: the value of the associated type `X` in trait `B` is already specified
--> test.rs:9:34
|
9 | impl<Y> Clone for Box<dyn B<X=Y, X=Y>> {
| --- ^^^ re-bound here
| |
| `X` bound here first
error[E0191]: the value of the associated type `X` in `A` must be specified
--> test.rs:9:27
|
2 | type X;
| ------ `A::X` defined here
...
6 | type X; // note: this is legal
| ------ `A::X` shadowed here
...
9 | impl<Y> Clone for Box<dyn B<X=Y, X=Y>> {
| ^^^^^^^^^^^ associated type `X` must be specified
|
help: consider renaming this associated type
--> test.rs:2:5
|
2 | type X;
| ^^^^^^
help: consider renaming this associated type
--> test.rs:6:5
|
6 | type X; // note: this is legal
| ^^^^^^
```
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0191, E0719.
For more information about an error, try `rustc --explain E0191`.
The rename help message is only emitted when the trait is local. This is true both for the supertrait as for the subtrait.
There might be cases where you can use the fully qualified path (for instance, in a where clause), but this PR currently does not deal with that.
fixes#100109
(continues from #117642, because I didn't know renaming the branch would close the PR)
Use `unwinding` crate for unwinding on Xous platform
This patch adds support for using [unwinding](https://github.com/nbdd0121/unwinding) on platforms where libunwinding isn't viable. An example of such a platform is `riscv32imac-unknown-xous-elf`.
### Background
The Rust project maintains a fork of llvm at [llvm-project](https://github.com/rust-lang/llvm-project/) where it applies patches on top of the llvm project. This mostly seems to be to get unwinding support for the SGX project, and there may be other patches that I'm unaware of.
There is a lot of machinery in the build system to support compiling `libunwind` on other platforms, and I needed to add additional patches to llvm in order to add support for Xous.
Rather than continuing down this path, it seemed much easier to use a Rust-based library. The `unwinding` crate by `@nbdd0121` fits this description perfectly.
### Future work
This could potentially replace the custom patches for `libunwind` on other platforms such as SGX, and could enable unwinding support on many more exotic platforms.
### Anti-goals
This is not designed to replace `libunwind` on tier-one platforms or those where unwinding support already exists. There is already a well-established approach for unwinding there. Instead, this aims to enable unwinding on new platforms where C++ code may be difficult to compile.
std: Invert logic for inclusion of `sys_common::net`
The `library/std/src/sys_common/net.rs` module is intended to define common implementations of networking-related APIs across a variety of platforms that share similar APIs (e.g. Berkeley-style sockets and all). This module is not included for more fringe targets however such as UEFI or "unknown" targets to libstd (those classified as `restricted-std`). Previously the `sys_common/net.rs` file was set up such that an allow-list indicated it shouldn't be used. This commit inverts the logic to have an allow-list of when it should be used instead.
The goal of this commit is to make it a bit easier to experiment with a new Rust target. Currently more esoteric targets are required to get an exception in this `cfg_if` block to use `crate::sys::net` such as for unsupported targets. With this inversion of logic only targets which actually support networking will be listed, where most of those are lumped under `cfg(unix)`.
Given that this change is likely to cause some breakage for some target by accident I've attempted to be somewhat robust with this by following these steps to defining the new predicate for inverted logic.
1. Take all supported targets and filter out all `cfg(unix)` ones as these should all support `sys_common/net.rs`.
2. Take remaining targets and filter out `cfg(windows)` ones.
3. The remaining dozen-or-so targets were all audited by hand. Mostly this included `target_os = "hermit"` and `target_os = "solid_asp3"` which required an allow-list entry, but remaining targets were all already excluded (didn't use `sys_common/net.rs` so they were left out.
If this causes breakage it should be relatively easy to fix and I'd be happy to follow-up with any PRs necessary.
Split `Vec::dedup_by` into 2 cycles
First cycle runs until we found 2 same elements, second runs after if there any found in the first one. This allows to avoid any memory writes until we found an item which we want to remove.
This leads to significant performance gains if all `Vec` items are kept: -40% on my benchmark with unique integers.
Results of benchmarks before implementation (including new benchmark where nothing needs to be removed):
* vec::bench_dedup_all_100 74.00ns/iter +/- 13.00ns
* vec::bench_dedup_all_1000 572.00ns/iter +/- 272.00ns
* vec::bench_dedup_all_100000 64.42µs/iter +/- 19.47µs
* __vec::bench_dedup_none_100 67.00ns/iter +/- 17.00ns__
* __vec::bench_dedup_none_1000 662.00ns/iter +/- 86.00ns__
* __vec::bench_dedup_none_10000 9.16µs/iter +/- 2.71µs__
* __vec::bench_dedup_none_100000 91.25µs/iter +/- 1.82µs__
* vec::bench_dedup_random_100 105.00ns/iter +/- 11.00ns
* vec::bench_dedup_random_1000 781.00ns/iter +/- 10.00ns
* vec::bench_dedup_random_10000 9.00µs/iter +/- 5.62µs
* vec::bench_dedup_random_100000 449.81µs/iter +/- 74.99µs
* vec::bench_dedup_slice_truncate_100 105.00ns/iter +/- 16.00ns
* vec::bench_dedup_slice_truncate_1000 2.65µs/iter +/- 481.00ns
* vec::bench_dedup_slice_truncate_10000 18.33µs/iter +/- 5.23µs
* vec::bench_dedup_slice_truncate_100000 501.12µs/iter +/- 46.97µs
Results after implementation:
* vec::bench_dedup_all_100 75.00ns/iter +/- 9.00ns
* vec::bench_dedup_all_1000 494.00ns/iter +/- 117.00ns
* vec::bench_dedup_all_100000 58.13µs/iter +/- 8.78µs
* __vec::bench_dedup_none_100 52.00ns/iter +/- 22.00ns__
* __vec::bench_dedup_none_1000 417.00ns/iter +/- 116.00ns__
* __vec::bench_dedup_none_10000 4.11µs/iter +/- 546.00ns__
* __vec::bench_dedup_none_100000 40.47µs/iter +/- 5.36µs__
* vec::bench_dedup_random_100 77.00ns/iter +/- 15.00ns
* vec::bench_dedup_random_1000 681.00ns/iter +/- 86.00ns
* vec::bench_dedup_random_10000 11.66µs/iter +/- 2.22µs
* vec::bench_dedup_random_100000 469.35µs/iter +/- 20.53µs
* vec::bench_dedup_slice_truncate_100 100.00ns/iter +/- 5.00ns
* vec::bench_dedup_slice_truncate_1000 2.55µs/iter +/- 224.00ns
* vec::bench_dedup_slice_truncate_10000 18.95µs/iter +/- 2.59µs
* vec::bench_dedup_slice_truncate_100000 492.85µs/iter +/- 72.84µs
Resolves#77772
P.S. Note that this is same PR as #92104 I just missed review then forgot about it.
Also, I cannot reopen that pull request so I am creating a new one.
I responded to remaining questions directly by adding commentaries to my code.
bootstrap(builder.rs): Don't explicitly warn against `semicolon_in_expressions_from_macros`
This already wasn't passed in bootstrap.py and the lint itself already warns-by-default for 2 years now and has already been added to the future-incompat group in Rust 1.68.
See https://github.com/rust-lang/rust/issues/79813 for the tracking issue.
Use OnceCell in cell module documentation
The spanning tree example in the std cell module implementation was created before `OnceCell` was added to Rust so it uses `RefCell`. However, in this case using `OnceCell` seems more appropriate and produces simpler code. As a bonus, this also means that all three cell types are presented in the examples of std cell module.
Add `deeply_normalize_for_diagnostics`, use it in coherence
r? lcnr
Normalize trait refs used for coherence error reporting with `-Ztrait-solver=next-coherence`.
Two things:
1. I said before that we can't add this to `TyErrCtxt` because we compute `OverlapResult`s even if there are no diagnostics being emitted, e.g. for a reservation impl.
2. I didn't want to add this to an `InferCtxtExt` trait because I felt it was unnecessary. I don't particularly care about the API though.
Pretty print `Fn<(..., ...)>` trait refs with parentheses (almost) always
It's almost always better, at least in diagnostics, to print `Fn(i32, u32)` instead of `Fn<(i32, u32)>`.
Related to but doesn't fix#118225. That needs a separate fix.
Add support for making lib features internal
We have the notion of an "internal" lang feature: a feature that is never intended to be stabilized, and using which can cause ICEs and other issues without that being considered a bug.
This extends that idea to lib features as well. It is an alternative to https://github.com/rust-lang/rust/pull/115623: instead of using an attribute to declare lib features internal, we simply do this based on the name. Everything ending in `_internals` or `_internal` is considered internal.
Then we rename `core_intrinsics` to `core_intrinsics_internal`, which fixes https://github.com/rust-lang/rust/issues/115597.
