Avoid exhausting stack space in dominator compression
Doesn't add a test case -- I ended up running into this while playing with the generated example from #43578, which we could do with a run-make test (to avoid checking a large code snippet into tree), but I suspect we don't want to wait for it to compile (locally it takes ~14s -- not terrible, but doesn't seem worth it to me). In practice stack space exhaustion is difficult to test for, too, since if we set the bound too low a different call structure above us (e.g., a nearer ensure_sufficient_stack call) would let the test pass even with the old impl, most likely.
Locally it seems like this manages to perform approximately equivalently to the recursion, but will run perf to confirm.
chalk: Fix wrong debrujin index in opaque type handling.
A folder in opaque type lowering was substituting all opaque type references with a variable with debrujin index 0 ignoring how many binders deep we are.
This caused an ICE with `Not enough bound vars: ^0 not found in []` ([full logs](https://gist.github.com/Dirbaio/2b9374ff4fce37afb9d665dc9f0000df)) with the following code.
```rust
fn main() -> () {}
async fn foo(x: u32) -> u32 {
x
}
```
With the fix, it no longer ICEs. It still doesn't typecheck due to generator issues. I've added a "known-bug" test so that at least it doesn't regress back to ICEing.
r? ``@jackh726``
Rollup of 5 pull requests
Successful merges:
- #93603 (Populate liveness facts when calling `get_body_with_borrowck_facts` without `-Z polonius`)
- #93870 (Fix switch on discriminant detection in a presence of coverage counters)
- #94355 (Add one more case to avoid ICE)
- #94363 (Remove needless borrows from core::fmt)
- #94377 (`check_used` should only look at actual `used` attributes)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Populate liveness facts when calling `get_body_with_borrowck_facts` without `-Z polonius`
For a new feature of [Flowistry](https://github.com/willcrichton/flowistry), a static-analysis tool, we need to obtain a `mir::Body`'s liveness facts using `get_body_with_borrowck_facts` (added in #86977). We'd like to do this without passing `-Z polonius` as a compiler arg to avoid borrow checking the entire crate.
Support for doing this was added in #88983, but the Polonius input facts used for liveness analysis are empty. This happens because the liveness input facts are populated in `liveness::generate` depending only on the value of `AllFacts::enabled` (which is toggled via compiler args).
This PR propagates the [`use_polonius`](8b09ba6a5d/compiler/rustc_borrowck/src/nll.rs (L168)) flag to `liveness::generate` to support populating liveness facts without requiring the `-Z polonius` flag.
This fix is somewhat patchy - if it'd be better to add more widely-accessible state (like `AllFacts::enabled`) I'd be open to ideas!
Rollup of 4 pull requests
Successful merges:
- #93850 (Don't ICE when an extern static is too big for the current architecture)
- #94154 (Wire up unstable rustc --check-cfg to rustdoc)
- #94353 (Fix debug_assert in unused lint pass)
- #94366 (Add missing item to release notes)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix debug_assert in unused lint pass
This fixes a debug assertion in the unused lint pass. As a side effect, this also improves the span generated for tuples in the `unused_must_use` lint.
found in #94329
A reproducer for this would be
```rust
fn main() { (1, (3,)); }
```
Not sure, if I should add a regression test for a `debug_assert`.
Don't ICE when an extern static is too big for the current architecture
Fixes#93760
Emit an error instead of ICEing when an `extern` static's size overflows the allowed maximum for the target.
Changes the error message in the existing `delay_span_bug` call to the true layout error, first for debugging purposes, but opted to leave in to potentially assist future developers as it was being reached in unexpected ways already.
Print `ParamTy` and `ParamConst` instead of displaying them
Display for `ParamTy` and `ParamConst` is implemented in terms of print.
Using print avoids creating a new `FmtPrinter` just to display the
parameter name.
r? `@Mark-Simulacrum`
Fix SGX docs build
Without this, I get
```
error[E0432]: unresolved import `crate::sys::cvt`
--> library/std/src/os/fd/owned.rs:12:5
|
12 | use crate::sys::cvt;
| ^^^^^^^^^^^^^^^ no `cvt` in `sys`
```
when running rustdoc on `std` for the x86_64-fortanix-unknown-sgx target.
Miri fn ptr check: don't use conservative null check
In https://github.com/rust-lang/rust/pull/94270 I used the wrong NULL check for function pointers: `memory.ptr_may_be_null` is conservative even on machines that support ptr-to-int casts, leading to false errors in Miri.
This fixes that problem, and also replaces that foot-fun of a method with `scalar_may_be_null` which is never unnecessarily conservative.
r? `@oli-obk`
Remove an unnecessary restriction in `dest_prop`
I had asked about this [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Do.20unions.20have.20active.20fields.3F) but didn't receive a response, so putting up this PR that makes the change I think we can. If it turns out that this is wrong, hopefully I'll find out here. Reposting my Zulip comment:
> Not sure what channel to put this into, so using this as a fallback. The dest prop MIR opt has this comment:
>
> ```rust
> //! Subtle case: If `dest` is a, or projects through a union, then we have to make sure that there
> //! remains an assignment to it, since that sets the "active field" of the union. But if `src` is
> //! a ZST, it might not be initialized, so there might not be any use of it before the assignment,
> //! and performing the optimization would simply delete the assignment, leaving `dest`
> //! uninitialized.
> ```
>
> In particular, the claim seems to be that we can't take
> ```
> x = ();
> y.field = x;
> ```
> where `y` is a union having `field: ()` as one of its variants, and optimize the entire thing away (assuming `x` is unused otherwise). As far as I know though, Rust unions don't have active fields. Is this comment correct and am I missing something? Is there a worry about this interacting poorly with FFI code/C unions/LTO or something?
This PR just removes that comment and the associated code. Also it fixes one unrelated comment that did not match the code it was commenting on.
r? rust-lang/mir-opt
don't special case `DefKind::Ctor` in encoding
considering that we still use `DefKind::Ctor` for these in `Res`, this seems weird and definitely felt like a bug when encountering it while working on #89862.
r? `@cjgillot`
Remove in band lifetimes
As discussed in t-lang backlog bonanza, the `in_band_lifetimes` FCP closed in favor for the feature not being stabilized. This PR removes `#![feature(in_band_lifetimes)]` in its entirety.
Let me know if this PR is too hasty, and if we should instead do something intermediate for deprecate the feature first.
r? `@scottmcm` (or feel free to reassign, just saw your last comment on #44524)
Closes#44524
This function was updated in a recent PR (92911) to be called without the caller
information passed in, but the function signature itself was not altered with
cfg_attr at the time.
This fixes a debug assertion in the unused lint pass. As a side effect,
this also improves the span generated for tuples in the
`unused_must_use` lint.
debuginfo: Simplify TypeMap used during LLVM debuginfo generation.
This PR simplifies the TypeMap that is used in `rustc_codegen_llvm::debuginfo::metadata`. It was unnecessarily complicated because it was originally implemented when types were not yet normalized before codegen. So it did it's own normalization and kept track of multiple unnormalized types being mapped to a single unique id.
This PR is based on https://github.com/rust-lang/rust/pull/93503, which is not merged yet.
The PR also removes the arena used for allocating string ids and instead uses `InlinableString` from the [inlinable_string](https://crates.io/crates/inlinable_string) crate. That might not be the best choice, since that crate does not seem to be very actively maintained. The [flexible-string](https://crates.io/crates/flexible-string) crate would be an alternative.
r? `@ghost`
Consider mutations as borrows in generator drop tracking
This is needed to match MIR more conservative approximation of any borrowed value being live across a suspend point (See #94067). This change considers an expression such as `x.y = z` to be a borrow of `x` and therefore keeps `x` live across suspend points.
r? `@nikomatsakis`
Use undef for (some) partially-uninit constants
There needs to be some limit to avoid perf regressions on large arrays
with undef in each element (see comment in the code).
Fixes: #84565
Original PR: #83698
Depends on LLVM 14: #93577
