Rewrite miri script in rust
This is a sketch of a rewrite of miri script in Rust. It does not include changes made in https://github.com/rust-lang/miri/pull/2908 yet. Environment variables are not properly propagated yet, which is something I plan to address.
This PR is mostly a heads-up about the ongoing effort and it's state.
It's definitely not the cleanest code I've seen in my life, but my first goal was feature/interface parity. I will iterate on it a bit before marking it as ready.
I wonder though how this should be integrated/tested. Are you aware of anyone using `./miri` in their scripts?
I guess we should keep existing `miri` script in place and let it run miri-script package directly?
CI should probably `cargo check` this package as well.
Fixes#2883
TB: Redefine trigger condition for protectors
The Coq formalization revealed that as currently implemented, read accesses did not always commute.
Indeed starting from a lazily initialized `Active` protected tag, applying a foreign read then a child read produces `Frozen`, but child read then foreign read triggers UB (because the child read initializes _before_ the `Active -> Frozen`).
This reformulation of when protectors trigger fixes that issue:
- instead of `Active + foreign read -> Frozen` and `Active -> Frozen` when protected is UB
- we do `Active + foreign read -> if protected { Disabled } else { Frozen }`
There is already precedent for transitions being dependent on the presence of a protector (`Reserved + foreign read -> if protected { Frozen } else { Reserved }`), and this has the nice side-effect of simplifying the protector trigger condition to just an equality check against `Disabled` since now there is protector UB iff a protected tag becomes `Disabled`.
In order not to introduce an extra `if`, it was decided that `Disabled -> Disabled` would be UB when protected, which was not the case previously. This is merely a theoretical for now because a protected `Disabled` is unreachable in the first place.
The extra test is not directly related to this modification, but also checks things related to protectors and lazy initialization.
Update the minimum external LLVM to 15
With this change, we'll have stable support for LLVM 15 through 17 (pending release).
For reference, the previous increase to LLVM 14 was #107573.
Change LLVM BOLT flags
I talked to the BOLT maintainers about the binary size effect of BOLT. Currently, BOLTing LLVM increases its binary size from ~120 MiB to ~170 MiB, which is not ideal. Now we can track both runtime performance and (rustc, LLVM, ...) artifact sizes in perf.RLO, so I'd like to try experimenting with changing the flags to reduce `libLLVM.so` size without regressing the performance gains of BOLT too much.
r? `@ghost`
Rename and allow `cast_ref_to_mut` lint
This PR is a small subset of https://github.com/rust-lang/rust/pull/112431, that is the renaming of the lint (`cast_ref_to_mut` -> `invalid_reference_casting`).
BUT also temporarily change the default level of the lint from deny-by-default to allow-by-default until https://github.com/rust-lang/rust/pull/112431 is merged.
r? `@Nilstrieb`
Rollup of 7 pull requests
Successful merges:
- #113773 (Don't attempt to compute layout of type referencing error)
- #114107 (Prevent people from assigning me as a PR reviewer)
- #114124 (tests/ui/proc-macro/*: Migrate FIXMEs to check-pass)
- #114171 (Fix switch-stdout test for none unix/windows platforms)
- #114172 (Fix issue_15149 test for the SGX target)
- #114173 (btree/map.rs: remove "Basic usage" text)
- #114174 (doc: replace wrong punctuation mark)
r? `@ghost`
`@rustbot` modify labels: rollup
ci: update ubuntu:20.04 builders to 22.04
This is mostly just maintenance to avoid bitrotting, but 22.04 also updates to cmake 3.22, so they don't need the manual builds from #113714 anymore.
Diagnostic namespace
This PR implements the basic infrastructure for accepting the `#[diagnostic]` attribute tool namespace as specified in https://github.com/rust-lang/rfcs/pull/3368. Note: This RFC is not merged yet, but it seems like it will be accepted soon. I open this PR early on to get feedback on the actual implementation as soon as possible. This hopefully enables getting at least the diagnostic namespace to stable rust "soon", so that crates do not need to bump their MSRV if we stabilize actual attributes in this namespace.
This PR only adds infrastructure accept attributes from this namespace, it does not add any specific attribute. Therefore the compiler will emit a lint warning for each attribute that's actually used. This namespace is added behind a feature flag, so it will be only available on a nightly compiler for now.
cc `@estebank` as they've supported me in planing, specifying and implementing this feature.
style-guide: don't flatten match arms with macro call
This pulls forward the gist of the text that was added to the style guide in https://github.com/rust-lang/style-team/pull/159 to account for needing to tweak/soften rustfmt's behavior based on the style guide prescriptions.
There were a few options I considered, noted below, and although I don't particularly love any of them, I felt this was the lesser of the evils.
r? `@joshtriplett`
Less `TokenTree` cloning
`TokenTreeCursor` has this comment on it:
```
// FIXME: Many uses of this can be replaced with by-reference iterator to avoid clones.
```
This PR completes that FIXME. It doesn't have much perf effect, but at least we now know that.
r? `@petrochenkov`
Revert "add tidy check that forbids issue ui test filenames"
This reverts commit 13e2abf6b3.
Reverting because an MCP was requested and it turned out there was a lack of a consensus on what to do in this area.
Build the first LLVM without LTO in try builds
Currently, we perform three LLVM builds in the Linux x64 dist builder, which is used for `try` builds:
1) "Normal" LLVM - takes ~5s to compile thanks to `sccache`, but ~8 minutes to link because of ThinLTO
2) PGO instrumented LLVM - same timings as 1)
3) PGO optimized LLVM - takes about 20 minutes to build
When I tried to disable LTO for build 1), it suddenly takes only about a minute to build, because the linking step is much faster. The first LLVM doesn't really need LTO all that much. Without it, it will be a bit slower to build `rustc` in two subsequent steps, but it seems that the ~7 minutes saved on linking it do win that back.
Btw, we can't use the host LLVM for build 1), because this LLVM then builds `rustc` in PGO instrumented mode, and we need the same compiler when later PGO optimizing `rustc`. And we want to use our in-house LLVM for that I think.
[rustdoc] If re-export is private, get the next item until a public one is found or expose the private item directly
Fixes#81141.
If we have:
```rust
use Private as Something;
pub fn foo() -> Something {}
```
Then `Something` will be replaced by `Private`.
r? `@notriddle`
rustdoc: fix cross-crate `impl Sized` & `impl ?Sized`
Previously, cross-crate impl-Trait (APIT, RPIT, etc.) that only consists of a single `Sized` bound (modulo outlives-bounds) and ones that are `?Sized` were incorrectly rendered. To give you a taste (before vs. after):
```diff
- fn sized(x: impl ) -> impl
+ fn sized(x: impl Sized) -> impl Sized
- fn sized_outlives<'a>(x: impl 'a) -> impl 'a
+ fn sized_outlives<'a>(x: impl Sized + 'a) -> impl Sized + 'a
- fn maybe_sized(x: &impl ) -> &impl
+ fn maybe_sized(x: &impl ?Sized) -> &impl ?Sized
- fn debug_maybe_sized(x: &impl Debug) -> &impl ?Sized + Debug
+ fn debug_maybe_sized(x: &(impl Debug + ?Sized)) -> &(impl Debug + ?Sized)
```
Moreover, we now surround impl-Trait that has multiple bounds with parentheses if they're the pointee of a reference or raw pointer type. This affects both local and cross-crate docs. The current output isn't correct (rustc would emit the error *ambiguous `+` in a type* if we fed the rendered code back to it).
---
Best reviewed commit by commit :)
`@rustbot` label A-cross-crate-reexports
