Subtree sync for rustc_codegen_cranelift #127694
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This is required by the objc2 crate Fixes rust-lang/rustc_codegen_cranelift#1504
Miri function identity hack: account for possible inlining Having a non-lifetime generic is not the only reason a function can be duplicated. Another possibility is that the function may be eligible for cross-crate inlining. So also take into account the inlining attribute in this Miri hack for function pointer identity. That said, `cross_crate_inlinable` will still sometimes return true even for `inline(never)` functions: - when they are `DefKind::Ctor(..) | DefKind::Closure` -- I assume those cannot be `InlineAttr::Never` anyway? - when `cross_crate_inline_threshold == InliningThreshold::Always` so maybe this is still not quite the right criterion to use for function pointer identity.
…, r=oli-obk,RalfJung
Support tail calls in mir via `TerminatorKind::TailCall`
This is one of the interesting bits in tail call implementation — MIR support.
This adds a new `TerminatorKind` which represents a tail call:
```rust
TailCall {
func: Operand<'tcx>,
args: Vec<Operand<'tcx>>,
fn_span: Span,
},
```
*Structurally* this is very similar to a normal `Call` but is missing a few fields:
- `destination` — tail calls don't write to destination, instead they pass caller's destination to the callee (such that eventual `return` will write to the caller of the function that used tail call)
- `target` — similarly to `destination` tail calls pass the caller's return address to the callee, so there is nothing to do
- `unwind` — I _think_ this is applicable too, although it's a bit confusing
- `call_source` — `become` forbids operators and is not created as a lowering of something else; tail calls always come from HIR (at least for now)
It might be helpful to read the interpreter implementation to understand what `TailCall` means exactly, although I've tried documenting it too.
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There are a few `FIXME`-questions still left, ideally we'd be able to answer them during review ':)
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r? `@oli-obk`
cc `@scottmcm` `@DrMeepster` `@JakobDegen`
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@bors r+ p=1 subtree sync |
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☀️ Test successful - checks-actions |
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Finished benchmarking commit (00167ab): comparison URL. Overall result: no relevant changes - no action needed@rustbot label: -perf-regression Instruction countThis benchmark run did not return any relevant results for this metric. Max RSS (memory usage)Results (primary 6.1%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesResults (secondary 2.9%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 705.014s -> 706.105s (0.15%) |
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Couple of bug fixes this time.
Fixes #125545
r? @ghost
@rustbot label +A-codegen +A-cranelift +T-compiler