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Rollup merge of #75195 - ssomers:btree_split_up_into_kv_mut, r=Mark-Simulacrum

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BTreeMap: purge innocent use of into_kv_mut

Replace the use of `into_kv_mut` into more precise calls. This makes more sense if you know that the single remaining use of `into_kv_mut` is in fact evil and can be trialled in court (#75200) and sent to a correction facility (#73971).

No real performance difference reported (but functions that might benefit a tiny constant bit like `BTreeMap::get_mut` aren't benchmarked):
```
benchcmp old new --threshold 5
 name                       old ns/iter  new ns/iter  diff ns/iter  diff %  speedup
 btree::map::clone_fat_100  63,073       59,256             -3,817  -6.05%   x 1.06
 btree::map::iter_100       3,514        3,235                -279  -7.94%   x 1.09
```
This commit is contained in:
Tyler Mandry 2020-08-14 14:46:45 -07:00 committed by GitHub
commit 83e75acdec
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2 changed files with 19 additions and 9 deletions
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6
library/alloc/src/collections/btree/map.rs
View File

@ -245,7 +245,7 @@ where
fn replace(&mut self, key: K) -> Option<K> {
let root = Self::ensure_is_owned(&mut self.root);
match search::search_tree::<marker::Mut<'_>, K, (), K>(root.node_as_mut(), &key) {
Found(handle) => Some(mem::replace(handle.into_kv_mut().0, key)),
Found(handle) => Some(mem::replace(handle.into_key_mut(), key)),
GoDown(handle) => {
VacantEntry { key, handle, length: &mut self.length, _marker: PhantomData }
.insert(());
@ -811,7 +811,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
{
let root_node = self.root.as_mut()?.node_as_mut();
match search::search_tree(root_node, key) {
Found(handle) => Some(handle.into_kv_mut().1),
Found(handle) => Some(handle.into_val_mut()),
GoDown(_) => None,
}
}
@ -2748,7 +2748,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn into_mut(self) -> &'a mut V {
self.handle.into_kv_mut().1
self.handle.into_val_mut()
}
/// Sets the value of the entry with the `OccupiedEntry`'s key,

22
library/alloc/src/collections/btree/node.rs
View File

@ -1067,6 +1067,16 @@ impl<'a, K: 'a, V: 'a, NodeType> Handle<NodeRef<marker::Immut<'a>, K, V, NodeTyp
}
impl<'a, K: 'a, V: 'a, NodeType> Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, marker::KV> {
pub fn into_key_mut(self) -> &'a mut K {
let keys = self.node.into_key_slice_mut();
unsafe { keys.get_unchecked_mut(self.idx) }
}
pub fn into_val_mut(self) -> &'a mut V {
let vals = self.node.into_val_slice_mut();
unsafe { vals.get_unchecked_mut(self.idx) }
}
pub fn into_kv_mut(self) -> (&'a mut K, &'a mut V) {
unsafe {
let (keys, vals) = self.node.into_slices_mut();
@ -1261,8 +1271,8 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
unsafe {
let (k, v, edge) = self.reborrow_mut().left_edge().descend().pop();
let k = mem::replace(self.reborrow_mut().into_kv_mut().0, k);
let v = mem::replace(self.reborrow_mut().into_kv_mut().1, v);
let k = mem::replace(self.kv_mut().0, k);
let v = mem::replace(self.kv_mut().1, v);
match self.reborrow_mut().right_edge().descend().force() {
ForceResult::Leaf(mut leaf) => leaf.push_front(k, v),
@ -1278,8 +1288,8 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
unsafe {
let (k, v, edge) = self.reborrow_mut().right_edge().descend().pop_front();
let k = mem::replace(self.reborrow_mut().into_kv_mut().0, k);
let v = mem::replace(self.reborrow_mut().into_kv_mut().1, v);
let k = mem::replace(self.kv_mut().0, k);
let v = mem::replace(self.kv_mut().1, v);
match self.reborrow_mut().left_edge().descend().force() {
ForceResult::Leaf(mut leaf) => leaf.push(k, v),
@ -1307,7 +1317,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
let left_kv = left_node.reborrow_mut().into_kv_pointers_mut();
let right_kv = right_node.reborrow_mut().into_kv_pointers_mut();
let parent_kv = {
let kv = self.reborrow_mut().into_kv_mut();
let kv = self.kv_mut();
(kv.0 as *mut K, kv.1 as *mut V)
};
@ -1364,7 +1374,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
let left_kv = left_node.reborrow_mut().into_kv_pointers_mut();
let right_kv = right_node.reborrow_mut().into_kv_pointers_mut();
let parent_kv = {
let kv = self.reborrow_mut().into_kv_mut();
let kv = self.kv_mut();
(kv.0 as *mut K, kv.1 as *mut V)
};