Add support for targets without unwinding in `mir-opt`, and improve `--bless` for it
The main goal of this PR is to add support for targets without unwinding support in the `mir-opt` test suite, by adding the `EMIT_MIR_FOR_EACH_PANIC_STRATEGY` comment. Similarly to 32bit vs 64bit, when that comment is present, blessed output files will have the `.panic-unwind` or `.panic-abort` suffix, and the right one will be chosen depending on the target's panic strategy.
The `EMIT_MIR_FOR_EACH_PANIC_STRATEGY` comment replaced all the `ignore-wasm32` comments in the `mir-opt` test suite, as those comments were added due to `wasm32` being a target without unwinding support. The comment was also added on other tests that were only executed on x86 but were still panic strategy dependent.
The `mir-opt` suite was then blessed, which caused a ton of churn as most of the existing output files had to be renamed and (mostly) duplicated with the abort strategy.
---
After [asking on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/mir-opt.20tests.20and.20panic.3Dabort), the main concern about this change is it'd make blessing the `mir-opt` suite even harder, as you'd need to both bless it with an unwinding target and an aborting target. This exacerbated the current situation, where you'd need to bless it with a 32bit and a 64bit target already.
Because of that, this PR also makes significant enhancements to `--bless` for the `mir-opt` suite, where it will automatically bless the suite four times with different targets, while requiring minimal cross-compilation.
To handle the 32bit vs 64bit blessing, there is now an hardcoded list of target mapping between 32bit and 64bit. The goal of the list is to find a related target that will *probably* work without requiring additional cross-compilation toolchains on the system. If a mapping is found, bootstrap will bless the suite with both targets, otherwise just with the current target.
To handle the panic strategy blessing (abort vs unwind), I had to resort to what I call "synthetic targets". For each of the target we're blessing (so either the current one, or a 32bit and a 64bit depending on the previous paragraph), bootstrap will extract the JSON spec of the target and change it to include `"panic-strategy": "abort"`. It will then build the standard library with this synthetic target, and bless the `mir-opt` suite with it.
As a result of these changes, blessing the `mir-opt` suite will actually bless it two or four times with different targets, ensuring all possible variants are actually blessed.
---
This PR is best reviewed commit-by-commit.
r? `@jyn514`
cc `@saethlin` `@oli-obk`
Collect VTable stats & add `-Zprint-vtable-sizes`
This is a bit hacky/buggy, but I'm not entirely sure how to fix it, so I want to ask reviewers for help...
To try this, use either of those:
- `cargo clean && RUSTFLAGS="-Zprint-vtable-sizes" cargo +toolchain b`
- `cargo clean && cargo rustc +toolchain -Zprint-vtable-sizes`
- `rustc +toolchain -Zprint-vtable-sizes ./file.rs`
Safe Transmute: Enable handling references
This patch enables support for references in Safe Transmute, by generating nested obligations during trait selection. Specifically, when we call `confirm_transmutability_candidate(...)`, we now recursively traverse the `rustc_transmute::Answer` tree and create obligations for all the `Answer` variants, some of which include multiple nested `Answer`s.
rustdoc-search: search never type with `!`
This feature extends rustdoc to support the syntax that most users will naturally attempt to use to search for diverging functions. Part of #60485
It's already possible to do this search with `primitive:never`, but that's not what the Rust language itself uses, so nobody will try it if they aren't told or helped along.
fix(resolve): update shadowed_glob more precision
- Fixes#109153
- Fixes#109962
## Why does it panic?
We use #109153 as an illustration.
The process of `resolve_imports` is:
| Iter | resolve | resolution of **`(Mod(root), Ident(bar) in type ns)`** |
| - | - | - |
| 0 | `use foo::*` | `binding` -> foo::bar, `shallowed_glob` -> `None` |
| 1 | `use bar::bar` | `binding` -> foo::bar::bar, `shallowed_glob` -> foo::bar |
| 2 | `use bar::*` | `binding` -> foo::bar::bar, `shallowed_glob` -> foo::bar::bar::bar |
So during `finalize_import`, the `root::bar` in `use bar::bar` had been pointed to `foo::bar::bar::bar`, which is different from the `initial_module` valued of `foo::bar`, therefore, the panic had been triggered.
## Try to solve it
~I think #109153 should check-pass rather than throw an ambiguous error. Following this idea, there are two ways to solve this problem:~
~1. Give up the `initial_module` and update `import.imported_module` after each resolution update. However, I think this method may have too much impact.~
~2. Do not update the `shadowed_glob` when it is defined.~
~To be honest, I am not sure if this is the right way to solve this ICE. Perhaps there is a better resolution.~
Edit: we had made the `resolution.shadowed_glob` update more detailed.
r? `@petrochenkov`
Make struct layout not depend on unsizeable tail
fixes (after backport) https://github.com/rust-lang/rust/issues/112048
Since unsizing `Ptr<Foo<T>>` -> `Ptr<Foo<U>` just copies the pointer and adds the metadata, the layout of `Foo` must not depend on niches in and alignment of the tail `T`.
Nominating for beta 1.71, because it will have this issue: `@rustbot` label beta-nominated
Add MVP suggestion for `unsafe_op_in_unsafe_fn`
Rebase of https://github.com/rust-lang/rust/pull/99827
cc tracking issue https://github.com/rust-lang/rust/issues/71668
No real changes since the original PR, just migrated the new suggestion to use fluent messages and added a couple more testcases, AFAICT from the discussion there were no outstanding changes requested.
Adjust UI tests for `unit_bindings` lint
- Explicitly annotate `let x: () = expr;` where `x` has unit type, or remove the unit binding to leave only `expr;` instead.
- Use `let () = init;` or `let pat = ();` where appropriate.
- Fix disjoint-capture-in-same-closure test which wasn't actually testing a closure: `tests/ui/closures/2229_closure_analysis/run_pass/disjoint-capture-in-same-closure.rs`.
Note that unfortunately there's *a lot* of UI tests, there are a couple of places where I may have left something like `let (): ()` (this is not needed but is left over from an ealier version of the lint) which is bad style.
This PR is to help with the `unit_bindings` lint at #112380.
This feature extends rustdoc to support the syntax that most users will
naturally attempt to use to search for diverging functions.
Part of #60485
It's already possible to do this search with `primitive:never`, but
that's not what the Rust language itself uses, so nobody will try it if
they aren't told or helped along.
- Create `Answer` type that is not just a type alias of `Result`
- Remove a usage of `map_layouts` to make the code easier to read
- Don't hide errors related to Unknown Layout when computing transmutability
Suggest using `ptr::null_mut` when user provided `ptr::null` to a function expecting `ptr::null_mut`
```
error[E0308]: mismatched types
--> $DIR/ptr-null-mutability-suggestions.rs:9:24
|
LL | expecting_null_mut(ptr::null());
| ------------------ ^^^^^^^^^^^
| | |
| | types differ in mutability
| | help: consider using `core::ptr::null_mut` instead: `core::ptr::null_mut()`
| arguments to this function are incorrect
|
= note: expected raw pointer `*mut u8`
found raw pointer `*const _`
note: function defined here
--> $DIR/ptr-null-mutability-suggestions.rs:6:4
|
LL | fn expecting_null_mut(_: *mut u8) {}
| ^^^^^^^^^^^^^^^^^^ ----------
```
Closes#85184.
- Either explicitly annotate `let x: () = expr;` where `x` has unit
type, or remove the unit binding to leave only `expr;` instead.
- Fix disjoint-capture-in-same-closure test
To reproduce the changes in this commit locally:
- Run `./x test tidy` and remove all the output files not associated
with a test file anymore, as reported by tidy.
- Run `./x test tests/mir-opt --bless` to generate the new outputs.
