Merge `PatParam`/`PatWithOr`, and `Expr`/`Expr2021`, for a few reasons.
- It's conceptually nice, because the two pattern kinds and the two
expression kinds are very similar.
- With expressions in particular, there are several places where both
expression kinds get the same treatment.
- It removes one unreachable match arm.
- Most importantly, for #124141 I will need to introduce a new type
`MetaVarKind` that is very similar to `NonterminalKind`, but records a
couple of extra fields for expression metavars. It's nicer to have a
single `MetaVarKind::Expr` expression variant to hold those extra
fields instead of duplicating them across two variants
`MetaVarKind::{Expr,Expr2021}`. And then it makes sense for patterns
to be treated the same way, and for `NonterminalKind` to also be
treated the same way.
I also clarified the comments, because I have long found them a little
hard to understand.
rustdoc: Add support for `missing_unsafe_on_extern` feature
Follow-up of https://github.com/rust-lang/rust/pull/124482.
Not sure if the `safe` keyword is supposed to be displayed or not though? For now I didn't add it in the generated doc, only `unsafe` as usual.
cc `@spastorino`
r? `@fmease`
Rollup of 3 pull requests
Successful merges:
- #126140 (Rename `std::fs::try_exists` to `std::fs::exists` and stabilize fs_try_exists)
- #126318 (Add a `x perf` command for integrating bootstrap with `rustc-perf`)
- #126552 (Remove use of const traits (and `feature(effects)`) from stdlib)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove use of const traits (and `feature(effects)`) from stdlib
The current uses are already unsound because they are using non-const impls in const contexts. We can reintroduce them by reverting the commit in this PR, after #120639 lands.
Also, make `effects` an incomplete feature.
cc `@rust-lang/project-const-traits`
r? `@compiler-errors`
Add a `x perf` command for integrating bootstrap with `rustc-perf`
This PR adds a new `x perf` command to bootstrap. The idea is to let rustc developers profile (`profile_local`) and benchmark (`bench_local`) a stage1/stage2 compiler directly from within `rust`.
Before, if you wanted to use `rustc-perf`, you had to clone it, set it up, copy the `rustc` sysroot after every change to `rust` etc. This is an attempt to automate that.
I opened this PR mostly for discussion. My idea is to offer an interface that looks something like this (a random sample of commands):
```bash
x perf --stage 2 profile eprintln
x perf --stage1 profile cachegrind
x perf benchmark --id baseline
x perf benchmark --id after-edit
x perf cmp baseline after-edit
```
In this PR, I'd like to only implement the simplest case (`profile_local (eprintln)`), because that only requires a single sysroot (you don't compare anything), and it's relatively easy to set up. Also, I'd like to avoid forcing developers to deal with the rustc-perf UI, so more complex use-cases (like benchmarking two sysroots and comparing the results) should probably wait for https://github.com/rust-lang/rustc-perf/issues/1734 (which is hopefully coming along soon-ish).
I'm not sure if it's better to do this in bootstrap directly, or if I should create some shim tool that will receive a `rustc` sysroot, and offer a simplified CLI on top of `rustc-perf`.
## Why is a separate CLI needed?
We definitely need to add some support to bootstrap to automate preparing `rustc-perf` and the `rustc` sysroot, but in theory after that we could just let people invoke `rustc-perf` manually. While that is definitely possible, you'd need to manually figure out where is your sysroot located, which seems annoying to me. The `rustc-perf` CLI is also relatively complex, and for this use-case it makes sense to only use a subset of it. So I thought that it would be better to offer a simplified interface on top of it that would make life easier for contributors. But maybe it's not worth it.
CC `@onur-ozkan`
Before if the closure passed to run_compiler emitted an error without
calling abort_if_errors and no diagnostics have been stashed,
run_compiler would return normally as if no error had occured.
Generalize `{Rc,Arc}::make_mut()` to unsized types.
* `{Rc,Arc}::make_mut()` now accept any type implementing the new unstable trait `core::clone::CloneToUninit`.
* `CloneToUninit` is implemented for `T: Clone` and for `[T] where T: Clone`.
* `CloneToUninit` is a generalization of the existing internal trait `alloc::alloc::WriteCloneIntoRaw`.
* New feature gate: `clone_to_uninit`
This allows performing `make_mut()` on `Rc<[T]>` and `Arc<[T]>`, which was not previously possible.
---
Previous PR description, now obsolete:
> Add `{Rc, Arc}::make_mut_slice()`
>
> These functions behave identically to `make_mut()`, but operate on `Arc<[T]>` instead of `Arc<T>`.
>
> This allows performing the operation on slices, which was not previously possible because `make_mut()` requires `T: Clone` (and slices, being `!Sized`, do not and currently cannot implement `Clone`).
>
> Feature gate: `make_mut_slice`
try-job: test-various
This requires introducing a new internal type `RcUninit` (and
`ArcUninit`), which can own an `RcBox<T>` without requiring it to be
initialized, sized, or a slice. This is similar to `UniqueRc`, but
`UniqueRc` doesn't support the allocator parameter, and there is no
`UniqueArc`.
This trait allows cloning DSTs, but is unsafe to implement and use
because it writes to possibly-uninitialized memory which must be of the
correct size, and must initialize that memory.
It is only implemented for `T: Clone` and `[T] where T: Clone`, but
additional implementations could be provided for specific `dyn Trait`
or custom-DST types.
Bootstrap command refactoring: refactor `BootstrapCommand` (step 1)
This PR is a first step towards https://rust-lang.zulipchat.com/#narrow/stream/326414-t-infra.2Fbootstrap.
It refactors `BoostrapCommand` to get it closer to a state where it is an actual command wrapper that can be routed through a central place of command execution, and also to make the distinction between printing output vs handling output programatically clearer (since now it's a mess).
The existing usages of `BootstrapCommand` are complicated primarily because of different ways of handling output. There are commands that:
1) Want to eagerly print stdout/stderr of the executed command, plus print an error message if the command fails (output mode `PrintAll`). Note that this error message attempts to print stdout/stderr of the command when `-v` is enabled, but that will always be empty, since this mode uses `.status()` and not `.output()`.
2) Want to eagerly print stdout/stderr of the executed command, but do not print any additional error message if it fails (output mode `PrintOutput`)
3) Want to capture stdout/stderr of the executed command, but print an error message if it fails (output mode `PrintFailure`). This means that the user wants to either ignore the output or handle it programatically, but that's not obvious from the name.
The difference between 1) and 2) (unless explicitly specified) is determined dynamically based on the bootstrap verbosity level.
It is very difficult for me to wrap my head around all these modes. I think that in a future PR, we should split these axes into e.g. this:
1) Do I want to handle the output programmatically or print it to the terminal? This should be a separate axis, true/false. (Note that "hiding the output" essentially just means saying that I handle it programmatically, and then I ignore the output).
2) Do I want to print a message if the command fails? Yes/No/Based on verbosity (which would be the default).
Then there is also the failure mode, but that is relatively simple to handle, the command execution will just shutdown bootstrap (either eagerly or late) when the command fails.
Note that this is just a first refactoring steps, there are a lot of other things to be done, so some things might not look "final" yet. The next steps are (not necessarily in this order):
- Remove `run` and `run_cmd` and implement everything in terms of `run_tracked` and rename `run_tracked` to `run`
- Implement the refactoring specified above (change how output modes work)
- Modify `BootstrapCmd` so that it stores `Command` instead of `&mut Command` and remove all the annoying `BootstrapCmd::from` by changing `Command::new` to `BootstrapCmd::new`
- Refactor the rest of command executions not currently using `BootstrapCmd` that can access Builder to use the correct output and failure modes. This will include passing Builder to additional places.
- Handle the most complex cases, such as output streaming. That will probably need to be handled separately.
- Refactor the rest of commands that cannot access builder (e.g. `Config::parse`) by introducing a new command context that will be passed to these places, and then stored in `Builder`. Move certain fields (such as `fail_fast`) from `Builder` to the command context.
- Handle the co-operation of `Builder`, `Build`, `Config` and command context. There are some fields and logic used during command execution that are distributed amongst `Builder/Build/Config`, so it will require some refactoring to make it work if the execution will happen on a separate place (in the command context).
- Refactor logging of commands, so that it is either logged to a file or printed in a nice hierarchical way that cooperates with the `Step` debug hierarchical output.
- Implement profiling of commands (add command durations to the command log, print a log of slowest commands and their execution counts at the end of bootstrap execution, perhaps store command executions to `metrics.json`).
- Implement caching of commands.
- Implement testing of commands through snapshot tests/mocking.
Best reviewed commit by commit.
r? ``@onur-ozkan``
