Start block is not allowed to have basic block predecessors
* The MIR validator is extended to detect potential violations.
* The start block has no predecessors after building MIR, so no changes are required there.
* The SimplifyCfg could previously violate this requirement when collapsing goto chains, so transformation is disabled for the start block, which also substantially simplifies the implementation.
* The LLVM function entry block also must not have basic block predecessors. Previously, to ensure that code generation had to perform necessary adjustments. This now became unnecessary.
The motivation behind the change is to align with analogous requirement in LLVM, and to avoid potential latent bugs like the one reported in #88043.
Disable the evaluation cache when in intercrate mode
It's possible to use the same `InferCtxt` with both
an intercrate and non-intercrate `SelectionContext`. However,
the local (inferctxt) evaluation cache is not aware of this
distinction, so this kind of `InferCtxt` re-use will pollute
the cache wth bad results.
This commit avoids the issue by disabling the evaluation cache
entirely during intercrate mode.
Simplify lazy DefPathHash decoding by using an on-disk hash table.
This PR simplifies the logic around mapping `DefPathHash` values encountered during incremental compilation to valid `DefId`s in the current session. It is able to do so by using an on-disk hash table encoding that allows for looking up values directly, i.e. without deserializing the entire table.
The main simplification comes from not having to keep track of `DefPathHashes` being used during the compilation session.
Skip single use lifetime lint for generated opaque types
Fix: #77175
The opaque type generated by the desugaring process of an async function uses the lifetimes defined by the originating function. The DefId for the lifetimes in the opaque type are different from the ones in the originating async function - as they should be, as far as I understand, and could therefore be considered a single use lifetimes, this causes the single_use_lifetimes lint to fail compilation if explicitly denied. This fix skips the lint for lifetimes used only once in generated opaque types for an async function that are declared in the parent async function definition.
More info in the comments on the original issue: 1 and 2
Avoid codegen for Result::into_ok in lang_start
This extra codegen seems to be the cause for the regressions in max-rss on #86034. While LLVM will certainly optimize the dead code away, avoiding it's generation in the first place seems good, particularly when it is so simple.
#86034 produced this [diff](https://gist.github.com/Mark-Simulacrum/95c7599883093af3b960c35ffadf4dab#file-86034-diff) for a simple `fn main() {}`. With this PR, that diff [becomes limited to just a few extra IR instructions](https://gist.github.com/Mark-Simulacrum/95c7599883093af3b960c35ffadf4dab#file-88988-from-pre-diff) -- no extra functions.
Note that these are pre-optimization; LLVM surely will eliminate this during optimization. However, that optimization can end up generating more work and bump memory usage, and this eliminates that.
Use explicit log level in tracing instrument macro
Specify a log level in tracing instrument macro explicitly.
Additionally reduce the used log level from a default info level to a
debug level (all of those appear to be developer oriented logs, so there
should be no need to include them in release builds).
Move the Lock into symbol::Interner
This makes it easier to make the symbol interner (near) lock free in case of concurrent accesses in the future.
With https://github.com/rust-lang/rust/pull/87867 landed this shouldn't affect performance anymore.
Fast reject for NeedsNonConstDrop
Hopefully fixes the regression in #88558.
I've always wanted to help with the performance of rustc, but it doesn't feel the same when you are fixing a regression caused by your own PR...
r? `@oli-obk`
If any block on a goto chain has more than one predecessor, then the new
start block would have basic block predecessors.
Skip the transformation for the start block altogether, to avoid
violating the new invariant that the start block does not have any basic
block predecessors.
inline(always) on check_recursion_limit
r? `@oli-obk`
#88558 caused a regression, this PR adds `#[inline(always)]` to `check_recursion_limit`, a possible suspect of that regression.
Rollup of 10 pull requests
Successful merges:
- #86422 (Emit clearer diagnostics for parens around `for` loop heads)
- #87460 (Point to closure when emitting 'cannot move out' for captured variable)
- #87566 (Recover invalid assoc type bounds using `==`)
- #88666 (Improve build command for compiler docs)
- #88899 (Do not issue E0071 if a type error has already been reported)
- #88949 (Fix handling of `hir::GenericArg::Infer` in `wrong_number_of_generic_args.rs`)
- #88953 (Add chown functions to std::os::unix::fs to change the owner and group of files)
- #88954 (Allow `panic!("{}", computed_str)` in const fn.)
- #88964 (Add rustdoc version into the help popup)
- #89012 (Suggest removing `#![feature]` for library features that have been stabilized)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Suggest removing `#![feature]` for library features that have been stabilized
Issue: https://github.com/rust-lang/rust/issues/88802
Delayed the check if #![feature] has been used to enable lib features in a non-nightly build to occur after TyCtxt has been constructed.
Add rustdoc version into the help popup
After a discussion with a rustdoc user about a specific behaviour, we realized we were not talking about the same version. To add on top of it, it was actually not that simple to find out the version since it was hosted documentation.
So to simplify things, I added the version into the help popup:
Does the version format looks or would you prefer that I add more information? We can also add the commit hash, commit date, host and release.
cc `@rust-lang/rustdoc`
r? `@jyn514`
Allow `panic!("{}", computed_str)` in const fn.
Special-case `panic!("{}", arg)` and translate it to `panic_display(&arg)`. `panic_display` will behave like `panic_any` in cosnt eval and behave like `panic!(format_args!("{}", arg))` in runtime.
This should bring Rust 2015 and 2021 to feature parity in terms of `const_panic`; and hopefully would unblock the stabilisation of #51999.
`@rustbot` modify labels: +T-compiler +T-libs +A-const-eval +A-const-fn
r? `@oli-obk`
Add chown functions to std::os::unix::fs to change the owner and group of files
This is a straightforward wrapper that uses the existing helpers for C
string handling and errno handling.
Having this available is convenient for UNIX utility programs written in
Rust, and avoids having to call unsafe functions like `libc::chown`
directly and handle errors manually, in a program that may otherwise be
entirely safe code.
In addition, these functions provide a more Rustic interface by
accepting appropriate traits and using `None` rather than `-1`.
Fix handling of `hir::GenericArg::Infer` in `wrong_number_of_generic_args.rs`
Fixes#87563. More precisely, I have fixed the "index out of bounds" error, which is what #87563 is about. The example given there still ICEs due to running into this `todo!()`, but I'd say that this is a separate issue:
c3c0f80d60/compiler/rustc_typeck/src/astconv/mod.rs (L460-L463)
Do not issue E0071 if a type error has already been reported
Fixes#88844. A suggested fix is already included in the error message for E0412, so with my changes, E0071 is simply not emitted anymore if the type in question is a "type error". This makes sense, I think, because we cannot confidently state that something is "not a struct" if we couldn't resolve it properly; and it's unnecessary to pollute the output with this additional error message, as it is a direct consequence of the former error.
I have also addressed the issue mentioned in https://github.com/rust-lang/rust/issues/88844#issuecomment-917324856 by changing the fixed example in the documentation to more closely match the erroneous code example.
Improve build command for compiler docs
It was rather complicated to document rustc crates. With this, you can directly run:
```console
x.py doc compiler
x.py doc compiler/rustc_hir_pretty
```
The second commit adds the handling of the `--open` flag.
r? `@Mark-Simulacrum`
Point to closure when emitting 'cannot move out' for captured variable
Attempts to fix#87456. The error message now points to the capturing closure, but I was not able to explain _why_ the closure implements `Fn` or `FnMut` (`TypeckResults::closure_kind_origins` did not contain anything for the closure in question).
cc `@Aaron1011`
