`for_each_assignment_mut` can skip assignment statements with side effects,
which can result in some assignment statements retrieving outdated value.
For example, it may skip a dereference assignment statement.
coverage: Avoid splitting spans during span extraction/refinement
This PR removes or simplifies some of the steps involved in extracting coverage-relevant spans from MIR, and preparing them for use in coverage instrumentation metadata.
A common theme is that we now try harder to avoid modifying or combining spans in non-trivial ways, because those modifications present the most risk for weird behaviour or ICEs.
The main changes are:
- When extracting spans from MIR call terminators, try to restrict them to just the function name.
- Instead of splitting spans around “holes”, just discard any span that overlaps with a hole.
- Instead of splitting macro-invocation spans into two parts, truncate them to just the macro name and subsequent `!`.
---
This results in a lot of tiny changes to the spans that end up in coverage metadata, and a few changes to coverage reports. Judging by test snapshots, these changes appear to be quite minor in practice.
This is a way to shrink call spans that doesn't involve mixing different spans,
and avoids overlap with argument spans.
This patch also removes some low-value comments that were causing rustfmt to
ignore the match arms.
Remove existing AFIDT implementation
This experiment will need to be reworked differently; I don't think we'll be going with the `dyn* Future` approach that is currently implemented.
r? oli-obk
Fixes#136286Fixes#137706Fixes#137895
Tracking:
* #133119
Rollup of 5 pull requests
Successful merges:
- #138283 (Enforce type of const param correctly in MIR typeck)
- #138439 (feat: check ARG_MAX on Unix platforms)
- #138502 (resolve: Avoid some unstable iteration)
- #138514 (Remove fake borrows of refs that are converted into non-refs in `MakeByMoveBody`)
- #138524 (Mark myself as unavailable for reviews temporarily)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove fake borrows of refs that are converted into non-refs in `MakeByMoveBody`
Remove fake borrows of closure captures if that capture has been replaced with a by-move version of that capture.
For example, given an async closure that looks like:
```
let f: Foo;
let c = async move || {
match f { ... }
};
```
... in this pair of coroutine-closure + coroutine, we capture `Foo` in the parent and `&Foo` in the child. We will emit two fake borrows like:
```
_2 = &fake shallow (*(_1.0: &Foo));
_3 = &fake shallow (_1.0: &Foo);
```
However, since the by-move-body transform is responsible for replacing `_1.0: &Foo` with `_1.0: Foo` (since the `AsyncFnOnce` coroutine will own `Foo` by value), that makes the second fake borrow obsolete since we never have an upvar of type `&Foo`, and we should replace it with a `nop`.
As a side-note, we don't actually even care about fake borrows here at all since they're fully a MIR borrowck artifact, and we don't need to borrowck by-move MIR bodies. But it's best to preserve as much as we can between these two bodies :)
Fixes#138501
r? oli-obk
This means that things like `<usize as Step>::forward_unchecked` and `<PartialOrd for f32>::le` will inline even if we've already done a bunch of inlining to find the calls to them.
Calculate predecessor count directly
Avoid allocating a vector of small vectors merely to determine how many
predecessors each basic block has.
Additionally use u8 and saturating operations. The pass only needs to
distinguish between [0..1] and [2..].
Revert <https://github.com/rust-lang/rust/pull/138084> to buy time to
consider options that avoids breaking downstream usages of cargo on
distributed `rustc-src` artifacts, where such cargo invocations fail due
to inability to inherit `lints` from workspace root manifest's
`workspace.lints` (this is only valid for the source rust-lang/rust
workspace, but not really the distributed `rustc-src` artifacts).
This breakage was reported in
<https://github.com/rust-lang/rust/issues/138304>.
This reverts commit 48caf81484, reversing
changes made to c6662879b2.
Don't include global asm in `mir_keys`, fix error body synthesis
r? oli-obk
Fixes#137470Fixes#137471Fixes#137472Fixes#137473
try-job: test-various
try-job: x86_64-apple-2
By naming them in `[workspace.lints.rust]` in the top-level
`Cargo.toml`, and then making all `compiler/` crates inherit them with
`[lints] workspace = true`. (I omitted `rustc_codegen_{cranelift,gcc}`,
because they're a bit different.)
The advantages of this over the current approach:
- It uses a standard Cargo feature, rather than special handling in
bootstrap. So, easier to understand, and less likely to get
accidentally broken in the future.
- It works for proc macro crates.
It's a shame it doesn't work for rustc-specific lints, as the comments
explain.
An inline asm terminator defines outputs along its target edges -- a
fallthrough target and labeled targets. Code generation implements this
by inserting code directly into the target blocks. This approach works
only if the target blocks don't have other predecessors.
Establish required invariant by extending existing code that breaks
critical edges before code generation.
Avoid allocating a vector of small vectors merely to determine how many
predecessors each basic block has.
Additionally use u8 and saturating operations. The pass only needs to
distinguish between [0..1] and [2..].
Inline `FnOnce`/`FnMut`/`Fn` shims once again
This PR fixes the argument checking for `extern "rust-call"` ABI functions with a spread arg, which do no expect their arguments to be exploded from a tuple like closures do.
Secondly, it removes the hack that prevented them from being inlined. This results in more work done by the compiler, but it does end up allowing us to inline functions we didn't before.
Fixes#137901
compiler: add `ExternAbi::is_rustic_abi`
Various parts of the compiler were hand-rolling this extremely simple check that is nonetheless easy to get wrong as the compiler evolves over time. Discourage them from being so "original" again by replacing it with a single implementation on the type that represents these ABIs. This simplifies a surprising amount of code as a result.
Also fixes#132981, an ICE that emerged due to other checks being made stricter.
