Optimize large array creation in const-eval
This changes repeated memcpy's to a memset for the case that we're propagating a single byte into a region of memory. It also optimizes the element-by-element copies to have a tighter loop; I'm pretty sure the old code was actually doing a multiply within each loop iteration.
For an 8GB array (`static SLICE: [u8; SIZE] = [0u8; 1 << 33];`) this takes us from ~23 seconds to ~6 seconds locally, which is spent roughly 50/50 in (a) memset to zero and (b) memcpy of the original place into a new place, when popping stack frame. The latter seems hard to avoid but is a big memcpy (since we're copying the type rather than initializing a region, so it's pretty fast), and the first is as good as it's going to get without special casing constant-valued arrays.
Closes https://github.com/rust-lang/rust/issues/55795. (That issue's references to lint checking don't appear true anymore, but I think this closes that case as something that is slow due to *time* pretty fully. An 8GB array taking only 6 seconds feels reasonable enough to not merit further tracking).
Get rid of the hir_owner query.
This query was meant as a firewall between `hir_owner_nodes` which is supposed to change often, and the queries that only depend on the item signature. That firewall was inefficient, leaking the contents of the HIR body through `HirId`s.
`hir_owner` incurs a significant cost, as we need to hash HIR twice in multiple modes. This PR proposes to remove it, and simplify the hashing scheme.
For the future, `def_kind`, `def_span`... are much more efficient for incremental decoupling, and should be preferred.
[rustc_data_structures] Use partition_point to find slice range end.
This PR uses approach introduced in https://github.com/rust-lang/rust/pull/114152 to find
the end of the range. It's much easier to understand and reason about invariants of such
implementation.
Technically it's possible to make it even shorter by returning `&[start..end]` unconditionally
because even if searched item is not present in the slice, `start` and `end` would point at
the same index, so the range would be empty. The reason I decided not to use this shorter
implementation is because it would involve more comparisons in case there are no elements
in the slice with key equal to `key`.
Also, not that it matters much, but this implementation also improves perf according to the
benchmark below:
https://gist.github.com/ttsugriy/63c0ed39ae132b131931fa1f8a3dea55
The results on my M1 macbook air are:
```
Running benches/bin_search_slice_benchmark.rs (target/release/deps/bin_search_slice_benchmark-90fa6d68c3bd1298)
Benchmarking multiply add/binary_search_slice: Collecting 100 samples in estimated 5.0002 s (1
multiply add/binary_search_slice
time: [44.719 ns 44.918 ns 45.158 ns]
No change in performance detected.
Found 3 outliers among 100 measurements (3.00%)
1 (1.00%) high mild
2 (2.00%) high severe
Benchmarking multiply add/binary_search_slice_new: Collecting 100 samples in estimated 5.0001
multiply add/binary_search_slice_new
time: [36.955 ns 37.060 ns 37.221 ns]
No change in performance detected.
Found 7 outliers among 100 measurements (7.00%)
3 (3.00%) high mild
4 (4.00%) high severe
```
Rollup of 8 pull requests
Successful merges:
- #119172 (Detect `NulInCStr` error earlier.)
- #119833 (Make tcx optional from StableMIR run macro and extend it to accept closures)
- #119967 (Add `PatKind::Err` to AST/HIR)
- #119978 (Move async closure parameters into the resultant closure's future eagerly)
- #120021 (don't store const var origins for known vars)
- #120038 (Don't create a separate "basename" when naming and opening a MIR dump file)
- #120057 (Don't ICE when deducing future output if other errors already occurred)
- #120073 (Remove spastorino from users_on_vacation)
r? `@ghost`
`@rustbot` modify labels: rollup
Add a new config to allow renaming of non-local defs
With #15656 we started disallowing renaming of non-local items. Although this makes sense there are some false positives that impacted users' workflows. So this config aims to mitigate this by giving users the liberty to disable this feature.
The reason why this is a draft is that I saw one of the tests fail and I am not sure if the "got" result even syntactically makes sense
Test case is :
```rust
check(
"Baz",
r#"
//- /lib.rs crate:lib new_source_root:library
pub struct S;
//- /main.rs crate:main deps:lib new_source_root:local
use lib::S$0;
"#,
"use lib::Baz;"
);
```
```
Left:
use lib::Baz;
Right:
use lib::Baz;Baz
Diff:
use lib::Baz;Baz
```
The first one succeeds because the functionality is already implemented.
The second one fails and represents the functionality to be implemented
in this PR.
Don't ICE when deducing future output if other errors already occurred
The situation can't really happen outside of erroneous code. What was interesting is that it ICEd before emitting any other diagnostics. This was because the other errors were silenced due to cycle_delay_bug cycle errors.
r? ```@compiler-errors```
fixes#119890
Don't create a separate "basename" when naming and opening a MIR dump file
These functions were split up by #77080, in order to support passing the dump file's “basename” (filename without extension) to the implementation of `-Zdump-mir-spanview`, so that it could be used as a page title.
That flag has since been removed (#119566), so now there's no particular reason for this code to handle the basename separately from the filename or full path.
This PR therefore restores things to (roughly) how they were before #77080.
Move async closure parameters into the resultant closure's future eagerly
Move async closure parameters into the closure's resultant future eagerly.
Before, we used to desugar `async |p1, p2, ..| { body }` as `|p1, p2, ..| { || async { body } }`. Now, we desugar the above like `|p1, p2, ..| { async move { let p1 = p1; let p2 = p2; ... body } }`. This mirrors the same desugaring that `async fn` does with its parameter types, and the compiler literally uses the same code via a shared helper function.
This removes the necessity for E0708, since now expressions like `async |x: i32| { x }` will not give you confusing borrow errors.
This does *not* fix the case where async closures have self-borrows. This will come with a general implementation of async closures, which is still in the works.
r? oli-obk
Make tcx optional from StableMIR run macro and extend it to accept closures
Change `run` macro to avoid sometimes unnecessary dependency on `TyCtxt`, and introduce `run_with_tcx` to capture use cases where `tcx` is required. Additionally, extend both macros to accept closures that may capture variables.
I've also modified the `internal()` method to make it safer, by accepting the type context to force the `'tcx` lifetime to match the context lifetime.
These are non-backward compatible changes, but they only affect internal APIs which are provided today as helper functions until we have a stable API to start the compiler.
Detect `NulInCStr` error earlier.
By making it an `EscapeError` instead of a `LitError`. This makes it like the other errors produced when checking string literals contents, e.g. for invalid escape sequences or bare CR chars.
NOTE: this means these errors are issued earlier, before expansion, which changes behaviour. It will be possible to move the check back to the later point if desired. If that happens, it's likely that all the string literal contents checks will be delayed together.
One nice thing about this: the old approach had some code in `report_lit_error` to calculate the span of the nul char from a range. This code used a hardwired `+2` to account for the `c"` at the start of a C string literal, but this should have changed to a `+3` for raw C string literals to account for the `cr"`, which meant that the caret in `cr"` nul error messages was one short of where it should have been. The new approach doesn't need any of this and avoids the off-by-one error.
r? ```@fee1-dead```
With #15656 we started disallowing renaming of non-local items.
Although this makes sense there are some false positives that
impacted users' workflows. So this config aims to mitigate this
by giving users the liberty to disable this feature.
Add way to express that no values are expected with check-cfg
This PR adds way to express no-values (no values expected) with `--check-cfg` by making empty `values()` no longer mean `values(none())` (internal: `&[None]`) and now be an empty list (internal: `&[]`).
### Context
Currently `--check-cfg` has a way to express that _any value is expected_ with `values(any())`, but has no way to do the inverse and say that _no value is expected_.
This would be particularly useful for build systems that control a config name and it's values as they could always declare a config name as expected and if in the current state they have values pass them and if not pass an empty list.
To give a more concrete example, Cargo `--check-cfg` currently needs to generate:
- `--check-cfg=cfg(feature, values(...))` for the case with declared features
- and `--check-cfg=cfg()` for the case without any features declared
This means that when there are no features declared, users will get an `unexpected config name` but from the point of view of Cargo the config name `feature` is expected, it's just that for now there aren't any values for it.
See [Cargo `check_cfg_args` function](92395d9010/src/cargo/core/compiler/mod.rs (L1263-L1281)) for more details.
### De-specializing *empty* `values()`
To solve this issue I propose that we "de-specialize" empty `values()` to no longer mean `values(none())` but to actually mean empty set/list. This is one of the last source of confusion for my-self and others with the `--check-cfg` syntax.
> The confusing part here is that an empty `values()` currently means the same as `values(none())`, i.e. an expected list of values with the _none_ variant (as in `#[cfg(name)]` where the value is none) instead of meaning an empty set.
Before the new `cfg()` syntax, defining the _none_ variant was only possible under certain circumstances, so in https://github.com/rust-lang/rust/pull/111068 I decided to make `values()` to mean the _none_ variant, but it is no longer necessary since https://github.com/rust-lang/rust/pull/119473 which introduced the `none()` syntax.
A simplified representation of the proposed "de-specialization" would be:
| Syntax | List/set of expected values |
|-----------------------------------------|-----------------------------|
| `cfg(name)`/`cfg(name, values(none()))` | `&[None]` |
| `cfg(name, values())` | `&[]` |
Note that I have my-self made the mistake of using an empty `values()` as meaning empty set, see https://github.com/rust-lang/cargo/pull/13011.
`@rustbot` label +F-check-cfg
r? `@petrochenkov`
cc `@epage`
`macro_rules` as macro name
This PR makes RA parse `macro_rules! {}` (note the missing identifier) as a `MACRO_CALL` instead of `MACRO_RULES`.
Fixes#15969.
