Try to clarify the confusingly-named `RustDev` and `RustcDev` steps
When trying to track down how the downloaded LLVM gets built and bundled, I was greatly confused by these step names.
I wasn't sure whether I could just rename them (since they correspond to the filename of the resulting tarball), but I at least wanted to leave behind some signposts to reduce confusion.
Ignore `branch-protection-check-IBT` run-make test
The old Makefile implementation (#110304) had an improper comparison which caused the test to never run. However, both the updated Makefile implementation and the rmake implementation fail (missing `.note.gnu.property`). This could be a bug in the original implementation or test flakiness.
Edit: Manually recreating the test case shows that `.note.gnu.property` does not appear in nightly.
```rust
// main.rs
fn main() {
println!("hello world");
}
```
```sh
$ rustc +nightly -V
rustc 1.81.0-nightly (c1b336cb6 2024-06-21)
$ rustc +stable -V
rustc 1.79.0 (129f3b996 2024-06-10)
```
```sh
$ rustc +nightly -Zcf-protection=branch -Clink-args=-nostartfiles -Csave-temps "-L$PWD" main.rs -o main
$ llvm-readobj --elf-output-style=GNU -nW main
Displaying notes found in: .note.gnu.build-id
Owner Data size Description
GNU 0x00000008 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: bcae34e6431b2a37
```
Compiling without the other flags still does not show `.note.gnu.property`.
```sh
$ rustc +nightly main.rs -o main
$ llvm-readobj --elf-output-style=GNU -nW main
Displaying notes found in: .note.ABI-tag
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
OS: Linux, ABI: 4.4.0
Displaying notes found in: .note.gnu.build-id
Owner Data size Description
GNU 0x00000008 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: d60d5f108b63bf3a
```
Compiling on stable shows `.note.gnu.property`.
```sh
$ rustc +stable main.rs -o main
$ llvm-readobj --elf-output-style=GNU -nW main
Displaying notes found in: .note.gnu.property
Owner Data size Description
GNU 0x00000010 NT_GNU_PROPERTY_TYPE_0 (property note)
Properties: x86 ISA needed: x86-64-baseline
Displaying notes found in: .note.gnu.build-id
Owner Data size Description
GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: 4a494eb578123314e6ff1caf1c8877e27004664f
Displaying notes found in: .note.ABI-tag
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
OS: Linux, ABI: 4.4.0
```
Part of #121876.
r? `@jieyouxu`
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`
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.
