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SsoHashSet/Map - genericiy over Q removed

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Due to performance regression, see SsoHashMap comment.
This commit is contained in:
Valerii Lashmanov 2020-10-02 20:13:21 -05:00
parent 92a0668c20
commit d1d2184db4
2 changed files with 72 additions and 89 deletions
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108
compiler/rustc_data_structures/src/sso/map.rs
View File

@ -1,7 +1,6 @@
use super::either_iter::EitherIter;
use crate::fx::FxHashMap;
use arrayvec::ArrayVec;
use std::borrow::Borrow;
use std::fmt;
use std::hash::Hash;
use std::iter::FromIterator;
@ -30,19 +29,45 @@ const SSO_ARRAY_SIZE: usize = 8;
///
/// Stores elements in a small array up to a certain length
/// and switches to `HashMap` when that length is exceeded.
///
/// Implements subset of HashMap API.
///
/// Missing HashMap API:
/// all hasher-related
/// try_reserve (unstable)
/// shrink_to (unstable)
/// drain_filter (unstable)
/// into_keys/into_values (unstable)
/// all raw_entry-related
/// PartialEq/Eq (requires sorting the array)
/// Entry::or_insert_with_key (unstable)
/// Vacant/Occupied entries and related
//
// FIXME: Implements subset of HashMap API.
//
// Missing HashMap API:
// all hasher-related
// try_reserve (unstable)
// shrink_to (unstable)
// drain_filter (unstable)
// into_keys/into_values (unstable)
// all raw_entry-related
// PartialEq/Eq (requires sorting the array)
// Entry::or_insert_with_key (unstable)
// Vacant/Occupied entries and related
//
// FIXME: In HashMap most methods accepting key reference
// accept reference to generic `Q` where `K: Borrow<Q>`.
//
// However, using this approach in `HashMap::get` apparently
// breaks inlining and noticeably reduces performance.
//
// Performance *should* be the same given that borrow is
// a NOP in most cases, but in practice that's not the case.
//
// Further investigation is required.
//
// Affected methods:
// SsoHashMap::get
// SsoHashMap::get_mut
// SsoHashMap::get_entry
// SsoHashMap::get_key_value
// SsoHashMap::contains_key
// SsoHashMap::remove
// SsoHashMap::remove_entry
// Index::index
// SsoHashSet::take
// SsoHashSet::get
// SsoHashSet::remove
// SsoHashSet::contains
#[derive(Clone)]
pub enum SsoHashMap<K, V> {
Array(ArrayVec<[(K, V); SSO_ARRAY_SIZE]>),
@ -232,14 +257,10 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> {
/// Removes a key from the map, returning the value at the key if the key
/// was previously in the map.
pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
pub fn remove(&mut self, key: &K) -> Option<V> {
match self {
SsoHashMap::Array(array) => {
if let Some(index) = array.iter().position(|(k, _v)| k.borrow() == key) {
if let Some(index) = array.iter().position(|(k, _v)| k == key) {
Some(array.swap_remove(index).1)
} else {
None
@ -251,14 +272,10 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> {
/// Removes a key from the map, returning the stored key and value if the
/// key was previously in the map.
pub fn remove_entry<Q: ?Sized>(&mut self, key: &Q) -> Option<(K, V)>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
pub fn remove_entry(&mut self, key: &K) -> Option<(K, V)> {
match self {
SsoHashMap::Array(array) => {
if let Some(index) = array.iter().position(|(k, _v)| k.borrow() == key) {
if let Some(index) = array.iter().position(|(k, _v)| k == key) {
Some(array.swap_remove(index))
} else {
None
@ -269,15 +286,11 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> {
}
/// Returns a reference to the value corresponding to the key.
pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
pub fn get(&self, key: &K) -> Option<&V> {
match self {
SsoHashMap::Array(array) => {
for (k, v) in array {
if k.borrow() == key {
if k == key {
return Some(v);
}
}
@ -288,15 +301,11 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> {
}
/// Returns a mutable reference to the value corresponding to the key.
pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
pub fn get_mut(&mut self, key: &K) -> Option<&mut V> {
match self {
SsoHashMap::Array(array) => {
for (k, v) in array {
if (*k).borrow() == key {
if k == key {
return Some(v);
}
}
@ -307,15 +316,11 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> {
}
/// Returns the key-value pair corresponding to the supplied key.
pub fn get_key_value<Q: ?Sized>(&self, key: &Q) -> Option<(&K, &V)>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
pub fn get_key_value(&self, key: &K) -> Option<(&K, &V)> {
match self {
SsoHashMap::Array(array) => {
for (k, v) in array {
if k.borrow() == key {
if k == key {
return Some((k, v));
}
}
@ -326,13 +331,9 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> {
}
/// Returns `true` if the map contains a value for the specified key.
pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool
where
K: Borrow<Q>,
Q: Hash + Eq,
{
pub fn contains_key(&self, key: &K) -> bool {
match self {
SsoHashMap::Array(array) => array.iter().any(|(k, _v)| k.borrow() == key),
SsoHashMap::Array(array) => array.iter().any(|(k, _v)| k == key),
SsoHashMap::Map(map) => map.contains_key(key),
}
}
@ -483,15 +484,14 @@ where
}
}
impl<'a, K, Q: ?Sized, V> Index<&'a Q> for SsoHashMap<K, V>
impl<'a, K, V> Index<&'a K> for SsoHashMap<K, V>
where
K: Eq + Hash + Borrow<Q>,
Q: Eq + Hash,
K: Eq + Hash,
{
type Output = V;
#[inline]
fn index(&self, key: &Q) -> &V {
fn index(&self, key: &K) -> &V {
self.get(key).expect("no entry found for key")
}
}

53
compiler/rustc_data_structures/src/sso/set.rs
View File

@ -1,4 +1,3 @@
use std::borrow::Borrow;
use std::fmt;
use std::hash::Hash;
use std::iter::FromIterator;
@ -9,20 +8,20 @@ use super::map::SsoHashMap;
///
/// Stores elements in a small array up to a certain length
/// and switches to `HashSet` when that length is exceeded.
///
/// Implements subset of HashSet API.
///
/// Missing HashSet API:
/// all hasher-related
/// try_reserve (unstable)
/// shrink_to (unstable)
/// drain_filter (unstable)
/// replace
/// get_or_insert/get_or_insert_owned/get_or_insert_with (unstable)
/// difference/symmetric_difference/intersection/union
/// is_disjoint/is_subset/is_superset
/// PartialEq/Eq (requires SsoHashMap implementation)
/// BitOr/BitAnd/BitXor/Sub
//
// FIXME: Implements subset of HashSet API.
//
// Missing HashSet API:
// all hasher-related
// try_reserve (unstable)
// shrink_to (unstable)
// drain_filter (unstable)
// replace
// get_or_insert/get_or_insert_owned/get_or_insert_with (unstable)
// difference/symmetric_difference/intersection/union
// is_disjoint/is_subset/is_superset
// PartialEq/Eq (requires SsoHashMap implementation)
// BitOr/BitAnd/BitXor/Sub
#[derive(Clone)]
pub struct SsoHashSet<T> {
map: SsoHashMap<T, ()>,
@ -115,21 +114,13 @@ impl<T: Eq + Hash> SsoHashSet<T> {
/// Removes and returns the value in the set, if any, that is equal to the given one.
#[inline]
pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T>
where
T: Borrow<Q>,
Q: Hash + Eq,
{
pub fn take(&mut self, value: &T) -> Option<T> {
self.map.remove_entry(value).map(entry_to_key)
}
/// Returns a reference to the value in the set, if any, that is equal to the given value.
#[inline]
pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T>
where
T: Borrow<Q>,
Q: Hash + Eq,
{
pub fn get(&self, value: &T) -> Option<&T> {
self.map.get_key_value(value).map(entry_to_key)
}
@ -146,21 +137,13 @@ impl<T: Eq + Hash> SsoHashSet<T> {
/// Removes a value from the set. Returns whether the value was
/// present in the set.
#[inline]
pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool
where
T: Borrow<Q>,
Q: Hash + Eq,
{
pub fn remove(&mut self, value: &T) -> bool {
self.map.remove(value).is_some()
}
/// Returns `true` if the set contains a value.
#[inline]
pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool
where
T: Borrow<Q>,
Q: Hash + Eq,
{
pub fn contains(&self, value: &T) -> bool {
self.map.contains_key(value)
}
}