Support enum variants in offset_of!
This MR implements support for navigating through enum variants in `offset_of!`, placing the enum variant name in the second argument to `offset_of!`. The RFC placed it in the first argument, but I think it interacts better with nested field access in the second, as you can then write things like
```rust
offset_of!(Type, field.Variant.field)
```
Alternatively, a syntactic distinction could be made between variants and fields (e.g. `field::Variant.field`) but I'm not convinced this would be helpful.
[RFC 3308 # Enum Support](https://rust-lang.github.io/rfcs/3308-offset_of.html#enum-support-offset_ofsomeenumstructvariant-field_on_variant)
Tracking Issue #106655.
Replace switch to unreachable by assume statements
`UnreachablePropagation` currently keeps some switch terminators alive in order to ensure codegen can infer the inequalities on the discriminants.
This PR proposes to encode those inequalities as `Assume` statements.
This allows to simplify MIR further by removing some useless terminators.
Historically, these errors existed so that the coverage debug code could dump
additional information before reporting a compiler bug. That debug code was
removed by #115962, so we can now simplify these methods by making them panic
when they detect a bug.
Enable cross-crate-inlining when MIR inlining is enabled
This would make https://github.com/rust-lang/rust/issues/117355 generally less obscure, and also seems like a good idea, even if for some reason someone wants MIR opts but no codegen opts.
- Sort dependencies and features sections.
- Add `tidy` markers to the sorted sections so they stay sorted.
- Remove empty `[lib`] sections.
- Remove "See more keys..." comments.
Excluded files:
- rustc_codegen_{cranelift,gcc}, because they're external.
- rustc_lexer, because it has external use.
- stable_mir, because it has external use.
See through aggregates in GVN
This PR is extracted from https://github.com/rust-lang/rust/pull/111344
The first 2 commit are cleanups to avoid repeated work. I propose to stop removing useless assignments as part of this pass, and let a later `SimplifyLocals` do it. This makes tests easier to read (among others).
The next 3 commits add a constant folding mechanism to the GVN pass, presented in https://github.com/rust-lang/rust/pull/116012. ~This pass is designed to only use global allocations, to avoid any risk of accidental modification of the stored state.~
The following commits implement opportunistic simplifications, in particular:
- projections of aggregates: `MyStruct { x: a }.x` gets replaced by `a`, works with enums too;
- projections of arrays: `[a, b][0]` becomes `a`;
- projections of repeat expressions: `[a; N][x]` becomes `a`;
- transform arrays of equal operands into a repeat rvalue.
Fixes https://github.com/rust-lang/miri/issues/3090
r? `@oli-obk`
Rollup of 5 pull requests
Successful merges:
- #115773 (tvOS simulator support on Apple Silicon for rustc)
- #117162 (Remove `cfg_match` from the prelude)
- #117311 (-Zunpretty help: add missing possible values)
- #117316 (Mark constructor of `BinaryHeap` as const fn)
- #117319 (explain why we don't inline when target features differ)
r? `@ghost`
`@rustbot` modify labels: rollup
Implement `gen` blocks in the 2024 edition
Coroutines tracking issue https://github.com/rust-lang/rust/issues/43122
`gen` block tracking issue https://github.com/rust-lang/rust/issues/117078
This PR implements `gen` blocks that implement `Iterator`. Most of the logic with `async` blocks is shared, and thus I renamed various types that were referring to `async` specifically.
An example usage of `gen` blocks is
```rust
fn foo() -> impl Iterator<Item = i32> {
gen {
yield 42;
for i in 5..18 {
if i.is_even() { continue }
yield i * 2;
}
}
}
```
The limitations (to be resolved) of the implementation are listed in the tracking issue
Only call `mir_const_qualif` if absolutely necessary
Pull the perf change out of https://github.com/rust-lang/rust/pull/113617
This should not have any impact on behaviour (if it does, we'll see an ICE)
Require target features to match exactly during inlining
In general it is not correct to inline a callee with a target features
that are subset of the callee. Require target features to match exactly
during inlining.
The exact match could be potentially relaxed, but this would require
identifying specific feature that are allowed to differ, those that need
to match, and those that can be present in caller but not in callee.
This resolves MIR part of #116573. For other concerns with respect to
the previous implementation also see areInlineCompatible in LLVM.
