fix handling of spurious accesses during retag
The `dereferenceable` attribute we emit for LLVM is checked during retag in Stacked Borrows.
However, we currently don't properly do that for retagging of `&mut !Unpin`, which this PR fixes.
Also this adjusts retagging to inform the data race model of the accesses as well.
Fixes https://github.com/rust-lang/miri/issues/2648.
Also fixes https://github.com/rust-lang/miri/issues/2693 since the same issue arose for retagging as well.
r? `@saethlin`
Separate lifetime ident from lifetime resolution in HIR
Drive-by: change how suggested generic args are computed.
Fixes https://github.com/rust-lang/rust/issues/103815
I recommend reviewing commit-by-commit.
Use `.wasm` extension when building for wasm in cargo-miri
WASM uses the `.wasm` file extension for its binaries (just like how windows uses `.exe`), so we need to set that as well.
I'm not sure whether gating this behind the wasm target is a good idea, maybe it makes more sense to always do it just like on windows.
Fix Dest Prop
Closes#82678, #79191 .
This was not originally a total re-write of the pass but is has gradually turned into one. Notable changes:
1. Significant improvements to documentation all around. The top of the file has been extended with a more precise argument for soundness. The code should be fairly readable, and I've done my best to add useful comments wherever possible. I would very much like for the bus factor to not be one on this code.
3. Improved handling of conflicts that are not visible in normal dataflow. This was the cause of #79191. Handling this correctly requires us to make decision about the semantics and specifically evaluation order of basically all MIR constructs (see specifically #68364#71117. The way this is implemented is based on my preferred resolution to these questions around the semantics of assignment statements.
4. Some re-architecting to improve performance. More details below.
5. Possible future improvements to this optimization are documented, and the code is written with the needs of those improvements in mind. The hope is that adding support for more precise analyses will not require a full re-write of this opt, but just localized changes.
### Regarding Performance
The previous approach had some performance issues; letting `l` be the number of locals and `s` be the number of statements/terminators, the runtime of the pass was `O(l^2 * s)`, both in theory and in practice. This version is smarter about not calculating unnecessary things and doing more caching. Our runtime is now dominated by one invocation of `MaybeLiveLocals` for each "round," and the number of rounds is less than 5 in over 90% of cases. This means it's linear-ish in practice.
r? `@oli-obk` who reviewed the last version of this, but review from anyone else would be more than welcome
This fixes a number of correctness issues from the previous version. Additionally, we use a new
strategy which has much better performance charactersitics and also finds more opportunities to
apply the optimization.
Revert "Don't set `is_preview` for clippy and rustfmt"
This reverts commit fb3e724d76, which broke `rustup update` for anyone with clippy or rustfmt installed.
Fixes https://github.com/rust-lang/rust/issues/104930.
r? `@Mark-Simulacrum`
`@bors` p=50 fixes nightly
Rollup of 7 pull requests
Successful merges:
- #104786 (Use the power of adding helper function to simplify code w/ `Mutability`)
- #104788 (Do not record unresolved const vars in generator interior)
- #104909 (Rename `normalize_opaque_types` to `reveal_opaque_types_in_bounds`)
- #104921 (Remove unnecessary binder from `get_impl_future_output_ty`)
- #104924 (jsondoclint: Accept trait alias is places where trait expected.)
- #104928 (rustdoc: use flexbox CSS to align sidebar button instead of position)
- #104943 (jsondoclint: Handle using enum variants and glob using enums.)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
jsondoclint: Handle using enum variants and glob using enums.
More work on jsondoclint for `core.json`
Closes#104942
r? `@GuillaumeGomez`
`@rustbot` modify labels: +A-testsuite
jsondoclint: Accept trait alias is places where trait expected.
More work to make `jsondoclint` work for `core.json`
Closes#104923
r? `@GuillaumeGomez`
`@rustbot` modify labels: +A-testsuite
Remove unnecessary binder from `get_impl_future_output_ty`
We never construct an `async fn` with a higher-ranked `impl Future` bound anyways, and basically all the call-sites already skip the binder.
Rename `normalize_opaque_types` to `reveal_opaque_types_in_bounds`
1. The query name is a bit misleading, since it doesn't do any associated type normalization, and
2. since it only takes a predicate list, it sounds a bit more powerful than it actually is.
Do not record unresolved const vars in generator interior
Don't record types in the generator interior when we see unresolved const variables.
We already do this for associated types -- this is important to avoid unresolved inference variables in the generator results during writeback, since the writeback results get stable hashed in incremental mode.
Fixes#104787
Track local frames incrementally during execution
https://github.com/rust-lang/miri/pull/2646 currently introduces a performance regression. This change removes that regression, and provides a minor perf improvement.
The existing lazy strategy for tracking the span we want to display is as efficient as it is only because we often create a `CurrentSpan` then never call `.get()`. Most of the calls to the `before_memory_read` and `before_memory_write` hooks do not create any event that we store in `AllocHistory`. But data races are totally different, any memory read or write may race, so every call to those hooks needs to access to the current local span.
So this changes to a strategy where we update some state in a `Thread` and `FrameExtra` incrementally, upon entering and existing each function call.
Before:
```
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/backtraces/Cargo.toml
Time (mean ± σ): 5.532 s ± 0.022 s [User: 5.444 s, System: 0.073 s]
Range (min … max): 5.516 s … 5.569 s 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/mse/Cargo.toml
Time (mean ± σ): 831.4 ms ± 3.0 ms [User: 783.8 ms, System: 46.7 ms]
Range (min … max): 828.7 ms … 836.1 ms 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/serde1/Cargo.toml
Time (mean ± σ): 1.975 s ± 0.021 s [User: 1.914 s, System: 0.059 s]
Range (min … max): 1.939 s … 1.990 s 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/serde2/Cargo.toml
Time (mean ± σ): 4.060 s ± 0.051 s [User: 3.983 s, System: 0.071 s]
Range (min … max): 3.972 s … 4.100 s 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/slice-get-unchecked/Cargo.toml
Time (mean ± σ): 784.9 ms ± 8.2 ms [User: 746.5 ms, System: 37.7 ms]
Range (min … max): 772.9 ms … 793.3 ms 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/unicode/Cargo.toml
Time (mean ± σ): 1.679 s ± 0.006 s [User: 1.623 s, System: 0.055 s]
Range (min … max): 1.673 s … 1.687 s 5 runs
```
After:
```
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/backtraces/Cargo.toml
Time (mean ± σ): 5.330 s ± 0.037 s [User: 5.232 s, System: 0.084 s]
Range (min … max): 5.280 s … 5.383 s 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/mse/Cargo.toml
Time (mean ± σ): 818.9 ms ± 3.7 ms [User: 776.8 ms, System: 41.3 ms]
Range (min … max): 813.5 ms … 822.5 ms 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/serde1/Cargo.toml
Time (mean ± σ): 1.927 s ± 0.011 s [User: 1.864 s, System: 0.061 s]
Range (min … max): 1.917 s … 1.945 s 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/serde2/Cargo.toml
Time (mean ± σ): 3.974 s ± 0.020 s [User: 3.893 s, System: 0.076 s]
Range (min … max): 3.956 s … 4.004 s 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/slice-get-unchecked/Cargo.toml
Time (mean ± σ): 780.0 ms ± 5.3 ms [User: 740.3 ms, System: 39.0 ms]
Range (min … max): 771.2 ms … 784.5 ms 5 runs
Benchmark 1: cargo +miri miri run --manifest-path /home/ben/miri/bench-cargo-miri/unicode/Cargo.toml
Time (mean ± σ): 1.643 s ± 0.007 s [User: 1.584 s, System: 0.058 s]
Range (min … max): 1.635 s … 1.654 s 5 runs
```
(This change is marginal, but the point is that it avoids a much more significant regression)
Remove AscribeUserTypeCx
r? ``@compiler-errors``
This basically inlines `AscribeUserTypeCx::relate_mir_and_user_ty` into `type_op_ascribe_user_type_with_span` which is the only place where it's used and makes direct use of `ObligationCtxt` API.
Unsupported query error now specifies if its unsupported for local or external crate
Fixes#101666.
I had to move `keys.rs` from `rustc_query_impl` to `rustc_middle`. I don't know if that is problematic. I couldn't think of any other way to get the needed information inside `rustc_middle`.
r? ```@jyn514```
Refine `instruction_set` MIR inline rules
Previously an exact match of the `instruction_set` attribute was required for an MIR inline to be considered. This change checks for an exact match *only* if the callee sets an `instruction_set` in the first place. When the callee does not declare an instruction set then it is considered to be platform agnostic code and it's allowed to be inline'd into the caller.
cc ``@oli-obk``
[Edit] Zulip Context: https://rust-lang.zulipchat.com/#narrow/stream/189540-t-compiler.2Fwg-mir-opt/topic/What.20exactly.20does.20the.20MIR.20optimizer.20do.3F
Manually implement PartialEq for Option<T> and specialize non-nullable types
This PR manually implements `PartialEq` and `StructuralPartialEq` for `Option`, which seems to produce slightly better codegen than the automatically derived implementation.
It also allows specializing on the `core::num::NonZero*` and `core::ptr::NonNull` types, taking advantage of the niche optimization by transmuting the `Option<T>` to `T` to be compared directly, which can be done in just two instructions.
A comparison of the original, new and specialized code generation is available [here](https://godbolt.org/z/dE4jxdYsa).
Ralf Jung