7dfdd64433
Optimize `UnDerefer` Addresses the performance [issues](https://github.com/rust-lang/rust/pull/98145#issuecomment-1183548597) faced here. r? `@oli-obk`
23 lines
712 B
Rust
23 lines
712 B
Rust
use rustc_data_structures::fx::FxHashMap;
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use rustc_middle::mir::*;
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use rustc_middle::ty::TyCtxt;
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/// Used for reverting changes made by `DerefSeparator`
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pub struct UnDerefer<'tcx> {
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pub tcx: TyCtxt<'tcx>,
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pub derefer_sidetable: FxHashMap<Local, Place<'tcx>>,
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}
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impl<'tcx> UnDerefer<'tcx> {
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#[inline]
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pub fn derefer(&self, place: PlaceRef<'tcx>, body: &Body<'tcx>) -> Option<Place<'tcx>> {
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let reffed = self.derefer_sidetable.get(&place.local)?;
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let new_place = reffed.project_deeper(place.projection, self.tcx);
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if body.local_decls[new_place.local].is_deref_temp() {
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return self.derefer(new_place.as_ref(), body);
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}
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Some(new_place)
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}
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}
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