cache type sizes in type-size limit visitor

This commit is contained in:
Rémy Rakic 2024-07-03 19:36:14 +00:00
parent 1cfd47fe0b
commit 529a3f4ce6

View File

@ -5,6 +5,7 @@ use crate::ty::{
self, EarlyBinder, GenericArgs, GenericArgsRef, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable,
TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor,
};
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::ErrorGuaranteed;
use rustc_hir as hir;
use rustc_hir::def::Namespace;
@ -388,13 +389,25 @@ impl<'tcx> InstanceKind<'tcx> {
}
fn type_length<'tcx>(item: impl TypeVisitable<TyCtxt<'tcx>>) -> usize {
struct Visitor {
struct Visitor<'tcx> {
type_length: usize,
cache: FxHashMap<Ty<'tcx>, usize>,
}
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for Visitor {
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for Visitor<'tcx> {
fn visit_ty(&mut self, t: Ty<'tcx>) {
if let Some(&value) = self.cache.get(&t) {
self.type_length += value;
return;
}
let prev = self.type_length;
self.type_length += 1;
t.super_visit_with(self);
// We don't try to use the cache if the type is fairly small.
if self.type_length > 16 {
self.cache.insert(t, self.type_length - prev);
}
}
fn visit_const(&mut self, ct: ty::Const<'tcx>) {
@ -402,7 +415,7 @@ fn type_length<'tcx>(item: impl TypeVisitable<TyCtxt<'tcx>>) -> usize {
ct.super_visit_with(self);
}
}
let mut visitor = Visitor { type_length: 0 };
let mut visitor = Visitor { type_length: 0, cache: Default::default() };
item.visit_with(&mut visitor);
visitor.type_length