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Split Intern::drop into hot and cold path

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This commit is contained in:
Jonas Schievink 2021-04-02 18:11:08 +02:00
parent afd83e0686
commit 76452956e4
1 changed files with 23 additions and 16 deletions
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39
crates/hir_def/src/intern.rs
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@ -53,31 +53,38 @@ impl<T: Internable> Interned<T> {
}
impl<T: Internable + ?Sized> Drop for Interned<T> {
#[inline]
fn drop(&mut self) {
// When the last `Ref` is dropped, remove the object from the global map.
if Arc::strong_count(&self.arc) == 2 {
// Only `self` and the global map point to the object.
let storage = T::storage().get();
let shard_idx = storage.determine_map(&self.arc);
let shard = &storage.shards()[shard_idx];
let mut shard = shard.write();
self.drop_slow();
}
}
}
// FIXME: avoid double lookup
let (arc, _) =
shard.get_key_value(&self.arc).expect("interned value removed prematurely");
impl<T: Internable + ?Sized> Interned<T> {
#[cold]
fn drop_slow(&mut self) {
let storage = T::storage().get();
let shard_idx = storage.determine_map(&self.arc);
let shard = &storage.shards()[shard_idx];
let mut shard = shard.write();
if Arc::strong_count(arc) != 2 {
// Another thread has interned another copy
return;
}
// FIXME: avoid double lookup
let (arc, _) = shard.get_key_value(&self.arc).expect("interned value removed prematurely");
shard.remove(&self.arc);
if Arc::strong_count(arc) != 2 {
// Another thread has interned another copy
return;
}
// Shrink the backing storage if the shard is less than 50% occupied.
if shard.len() * 2 < shard.capacity() {
shard.shrink_to_fit();
}
shard.remove(&self.arc);
// Shrink the backing storage if the shard is less than 50% occupied.
if shard.len() * 2 < shard.capacity() {
shard.shrink_to_fit();
}
}
}