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Convert ShardedHashMap to use hashbrown::HashTable

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The `hash_raw_entry` feature has finished fcp-close, so the compiler
should stop using it to allow its removal. Several `Sharded` maps were
using raw entries to avoid re-hashing between shard and map lookup, and
we can do that with `hashbrown::HashTable` instead.
This commit is contained in:
Josh Stone 2025-02-26 20:47:53 -08:00
parent 9fb94b32df
commit 3b0c2585c8
10 changed files with 109 additions and 66 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Cargo.lock
View file

@ -1491,6 +1491,7 @@ version = "0.15.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
dependencies = [
"allocator-api2",
"foldhash",
"serde",
]
@ -3492,6 +3493,7 @@ dependencies = [
"either",
"elsa",
"ena",
"hashbrown 0.15.2",
"indexmap",
"jobserver",
"libc",

5
compiler/rustc_data_structures/Cargo.toml
View file

@ -29,6 +29,11 @@ thin-vec = "0.2.12"
tracing = "0.1"
# tidy-alphabetical-end
[dependencies.hashbrown]
version = "0.15.2"
default-features = false
features = ["nightly"] # for may_dangle
[dependencies.parking_lot]
version = "0.12"

1
compiler/rustc_data_structures/src/lib.rs
View file

@ -24,7 +24,6 @@
#![feature(dropck_eyepatch)]
#![feature(extend_one)]
#![feature(file_buffered)]
#![feature(hash_raw_entry)]
#![feature(macro_metavar_expr)]
#![feature(map_try_insert)]
#![feature(min_specialization)]

2
compiler/rustc_data_structures/src/marker.rs
View file

@ -76,6 +76,7 @@ impl_dyn_send!(
[crate::sync::RwLock<T> where T: DynSend]
[crate::tagged_ptr::TaggedRef<'a, P, T> where 'a, P: Sync, T: Send + crate::tagged_ptr::Tag]
[rustc_arena::TypedArena<T> where T: DynSend]
[hashbrown::HashTable<T> where T: DynSend]
[indexmap::IndexSet<V, S> where V: DynSend, S: DynSend]
[indexmap::IndexMap<K, V, S> where K: DynSend, V: DynSend, S: DynSend]
[thin_vec::ThinVec<T> where T: DynSend]
@ -153,6 +154,7 @@ impl_dyn_sync!(
[crate::tagged_ptr::TaggedRef<'a, P, T> where 'a, P: Sync, T: Sync + crate::tagged_ptr::Tag]
[parking_lot::lock_api::Mutex<R, T> where R: DynSync, T: ?Sized + DynSend]
[parking_lot::lock_api::RwLock<R, T> where R: DynSync, T: ?Sized + DynSend + DynSync]
[hashbrown::HashTable<T> where T: DynSync]
[indexmap::IndexSet<V, S> where V: DynSync, S: DynSync]
[indexmap::IndexMap<K, V, S> where K: DynSync, V: DynSync, S: DynSync]
[smallvec::SmallVec<A> where A: smallvec::Array + DynSync]

95
compiler/rustc_data_structures/src/sharded.rs
View file

@ -1,11 +1,11 @@
use std::borrow::Borrow;
use std::collections::hash_map::RawEntryMut;
use std::hash::{Hash, Hasher};
use std::iter;
use std::{iter, mem};
use either::Either;
use hashbrown::hash_table::{Entry, HashTable};
use crate::fx::{FxHashMap, FxHasher};
use crate::fx::FxHasher;
use crate::sync::{CacheAligned, Lock, LockGuard, Mode, is_dyn_thread_safe};
// 32 shards is sufficient to reduce contention on an 8-core Ryzen 7 1700,
@ -140,17 +140,67 @@ pub fn shards() -> usize {
1
}
pub type ShardedHashMap<K, V> = Sharded<FxHashMap<K, V>>;
pub type ShardedHashMap<K, V> = Sharded<HashTable<(K, V)>>;
impl<K: Eq, V> ShardedHashMap<K, V> {
pub fn with_capacity(cap: usize) -> Self {
Self::new(|| FxHashMap::with_capacity_and_hasher(cap, rustc_hash::FxBuildHasher::default()))
Self::new(|| HashTable::with_capacity(cap))
}
pub fn len(&self) -> usize {
self.lock_shards().map(|shard| shard.len()).sum()
}
}
impl<K: Eq + Hash, V> ShardedHashMap<K, V> {
#[inline]
pub fn get<Q>(&self, key: &Q) -> Option<V>
where
K: Borrow<Q>,
Q: Hash + Eq,
V: Clone,
{
let hash = make_hash(key);
let shard = self.lock_shard_by_hash(hash);
let (_, value) = shard.find(hash, |(k, _)| k.borrow() == key)?;
Some(value.clone())
}
#[inline]
pub fn get_or_insert_with(&self, key: K, default: impl FnOnce() -> V) -> V
where
V: Copy,
{
let hash = make_hash(&key);
let mut shard = self.lock_shard_by_hash(hash);
match table_entry(&mut shard, hash, &key) {
Entry::Occupied(e) => e.get().1,
Entry::Vacant(e) => {
let value = default();
e.insert((key, value));
value
}
}
}
#[inline]
pub fn insert(&self, key: K, value: V) -> Option<V> {
let hash = make_hash(&key);
let mut shard = self.lock_shard_by_hash(hash);
match table_entry(&mut shard, hash, &key) {
Entry::Occupied(e) => {
let previous = mem::replace(&mut e.into_mut().1, value);
Some(previous)
}
Entry::Vacant(e) => {
e.insert((key, value));
None
}
}
}
}
impl<K: Eq + Hash + Copy> ShardedHashMap<K, ()> {
#[inline]
pub fn intern_ref<Q: ?Sized>(&self, value: &Q, make: impl FnOnce() -> K) -> K
@ -160,13 +210,12 @@ impl<K: Eq + Hash + Copy> ShardedHashMap<K, ()> {
{
let hash = make_hash(value);
let mut shard = self.lock_shard_by_hash(hash);
let entry = shard.raw_entry_mut().from_key_hashed_nocheck(hash, value);
match entry {
RawEntryMut::Occupied(e) => *e.key(),
RawEntryMut::Vacant(e) => {
match table_entry(&mut shard, hash, value) {
Entry::Occupied(e) => e.get().0,
Entry::Vacant(e) => {
let v = make();
e.insert_hashed_nocheck(hash, v, ());
e.insert((v, ()));
v
}
}
@ -180,13 +229,12 @@ impl<K: Eq + Hash + Copy> ShardedHashMap<K, ()> {
{
let hash = make_hash(&value);
let mut shard = self.lock_shard_by_hash(hash);
let entry = shard.raw_entry_mut().from_key_hashed_nocheck(hash, &value);
match entry {
RawEntryMut::Occupied(e) => *e.key(),
RawEntryMut::Vacant(e) => {
match table_entry(&mut shard, hash, &value) {
Entry::Occupied(e) => e.get().0,
Entry::Vacant(e) => {
let v = make(value);
e.insert_hashed_nocheck(hash, v, ());
e.insert((v, ()));
v
}
}
@ -203,17 +251,30 @@ impl<K: Eq + Hash + Copy + IntoPointer> ShardedHashMap<K, ()> {
let hash = make_hash(&value);
let shard = self.lock_shard_by_hash(hash);
let value = value.into_pointer();
shard.raw_entry().from_hash(hash, |entry| entry.into_pointer() == value).is_some()
shard.find(hash, |(k, ())| k.into_pointer() == value).is_some()
}
}
#[inline]
pub fn make_hash<K: Hash + ?Sized>(val: &K) -> u64 {
fn make_hash<K: Hash + ?Sized>(val: &K) -> u64 {
let mut state = FxHasher::default();
val.hash(&mut state);
state.finish()
}
#[inline]
fn table_entry<'a, K, V, Q>(
table: &'a mut HashTable<(K, V)>,
hash: u64,
key: &Q,
) -> Entry<'a, (K, V)>
where
K: Hash + Borrow<Q>,
Q: ?Sized + Eq,
{
table.entry(hash, move |(k, _)| k.borrow() == key, |(k, _)| make_hash(k))
}
/// Get a shard with a pre-computed hash value. If `get_shard_by_value` is
/// ever used in combination with `get_shard_by_hash` on a single `Sharded`
/// instance, then `hash` must be computed with `FxHasher`. Otherwise,

20
compiler/rustc_middle/src/mir/interpret/mod.rs
View file

@ -452,12 +452,7 @@ impl<'tcx> TyCtxt<'tcx> {
}
let id = self.alloc_map.reserve();
debug!("creating alloc {:?} with id {id:?}", alloc_salt.0);
let had_previous = self
.alloc_map
.to_alloc
.lock_shard_by_value(&id)
.insert(id, alloc_salt.0.clone())
.is_some();
let had_previous = self.alloc_map.to_alloc.insert(id, alloc_salt.0.clone()).is_some();
// We just reserved, so should always be unique.
assert!(!had_previous);
dedup.insert(alloc_salt, id);
@ -510,7 +505,7 @@ impl<'tcx> TyCtxt<'tcx> {
/// local dangling pointers and allocations in constants/statics.
#[inline]
pub fn try_get_global_alloc(self, id: AllocId) -> Option<GlobalAlloc<'tcx>> {
self.alloc_map.to_alloc.lock_shard_by_value(&id).get(&id).cloned()
self.alloc_map.to_alloc.get(&id)
}
#[inline]
@ -529,9 +524,7 @@ impl<'tcx> TyCtxt<'tcx> {
/// Freezes an `AllocId` created with `reserve` by pointing it at an `Allocation`. Trying to
/// call this function twice, even with the same `Allocation` will ICE the compiler.
pub fn set_alloc_id_memory(self, id: AllocId, mem: ConstAllocation<'tcx>) {
if let Some(old) =
self.alloc_map.to_alloc.lock_shard_by_value(&id).insert(id, GlobalAlloc::Memory(mem))
{
if let Some(old) = self.alloc_map.to_alloc.insert(id, GlobalAlloc::Memory(mem)) {
bug!("tried to set allocation ID {id:?}, but it was already existing as {old:#?}");
}
}
@ -539,11 +532,8 @@ impl<'tcx> TyCtxt<'tcx> {
/// Freezes an `AllocId` created with `reserve` by pointing it at a static item. Trying to
/// call this function twice, even with the same `DefId` will ICE the compiler.
pub fn set_nested_alloc_id_static(self, id: AllocId, def_id: LocalDefId) {
if let Some(old) = self
.alloc_map
.to_alloc
.lock_shard_by_value(&id)
.insert(id, GlobalAlloc::Static(def_id.to_def_id()))
if let Some(old) =
self.alloc_map.to_alloc.insert(id, GlobalAlloc::Static(def_id.to_def_id()))
{
bug!("tried to set allocation ID {id:?}, but it was already existing as {old:#?}");
}

4
compiler/rustc_middle/src/ty/context.rs
View file

@ -2336,8 +2336,8 @@ macro_rules! sty_debug_print {
$(let mut $variant = total;)*
for shard in tcx.interners.type_.lock_shards() {
let types = shard.keys();
for &InternedInSet(t) in types {
let types = shard.iter();
for &(InternedInSet(t), ()) in types {
let variant = match t.internee {
ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
ty::Float(..) | ty::Str | ty::Never => continue,

29
compiler/rustc_query_system/src/dep_graph/graph.rs
View file

@ -1,5 +1,4 @@
use std::assert_matches::assert_matches;
use std::collections::hash_map::Entry;
use std::fmt::Debug;
use std::hash::Hash;
use std::marker::PhantomData;
@ -9,7 +8,7 @@ use std::sync::atomic::{AtomicU32, Ordering};
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::profiling::{QueryInvocationId, SelfProfilerRef};
use rustc_data_structures::sharded::{self, Sharded};
use rustc_data_structures::sharded::{self, ShardedHashMap};
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::{AtomicU64, Lock};
use rustc_data_structures::unord::UnordMap;
@ -619,7 +618,7 @@ impl<D: Deps> DepGraphData<D> {
if let Some(prev_index) = self.previous.node_to_index_opt(dep_node) {
self.current.prev_index_to_index.lock()[prev_index]
} else {
self.current.new_node_to_index.lock_shard_by_value(dep_node).get(dep_node).copied()
self.current.new_node_to_index.get(dep_node)
}
}
@ -1048,7 +1047,7 @@ rustc_index::newtype_index! {
/// first, and `data` second.
pub(super) struct CurrentDepGraph<D: Deps> {
encoder: GraphEncoder<D>,
new_node_to_index: Sharded<FxHashMap<DepNode, DepNodeIndex>>,
new_node_to_index: ShardedHashMap<DepNode, DepNodeIndex>,
prev_index_to_index: Lock<IndexVec<SerializedDepNodeIndex, Option<DepNodeIndex>>>,
/// This is used to verify that fingerprints do not change between the creation of a node
@ -1117,12 +1116,9 @@ impl<D: Deps> CurrentDepGraph<D> {
profiler,
previous,
),
new_node_to_index: Sharded::new(|| {
FxHashMap::with_capacity_and_hasher(
new_node_to_index: ShardedHashMap::with_capacity(
new_node_count_estimate / sharded::shards(),
Default::default(),
)
}),
),
prev_index_to_index: Lock::new(IndexVec::from_elem_n(None, prev_graph_node_count)),
anon_id_seed,
#[cfg(debug_assertions)]
@ -1152,14 +1148,9 @@ impl<D: Deps> CurrentDepGraph<D> {
edges: EdgesVec,
current_fingerprint: Fingerprint,
) -> DepNodeIndex {
let dep_node_index = match self.new_node_to_index.lock_shard_by_value(&key).entry(key) {
Entry::Occupied(entry) => *entry.get(),
Entry::Vacant(entry) => {
let dep_node_index = self.encoder.send(key, current_fingerprint, edges);
entry.insert(dep_node_index);
dep_node_index
}
};
let dep_node_index = self
.new_node_to_index
.get_or_insert_with(key, || self.encoder.send(key, current_fingerprint, edges));
#[cfg(debug_assertions)]
self.record_edge(dep_node_index, key, current_fingerprint);
@ -1257,7 +1248,7 @@ impl<D: Deps> CurrentDepGraph<D> {
) {
let node = &prev_graph.index_to_node(prev_index);
debug_assert!(
!self.new_node_to_index.lock_shard_by_value(node).contains_key(node),
!self.new_node_to_index.get(node).is_some(),
"node from previous graph present in new node collection"
);
}
@ -1382,7 +1373,7 @@ fn panic_on_forbidden_read<D: Deps>(data: &DepGraphData<D>, dep_node_index: DepN
if dep_node.is_none() {
// Try to find it among the new nodes
for shard in data.current.new_node_to_index.lock_shards() {
if let Some((node, _)) = shard.iter().find(|(_, index)| **index == dep_node_index) {
if let Some((node, _)) = shard.iter().find(|(_, index)| *index == dep_node_index) {
dep_node = Some(*node);
break;
}

1
compiler/rustc_query_system/src/lib.rs
View file

@ -3,7 +3,6 @@
#![feature(assert_matches)]
#![feature(core_intrinsics)]
#![feature(dropck_eyepatch)]
#![feature(hash_raw_entry)]
#![feature(let_chains)]
#![feature(min_specialization)]
#![warn(unreachable_pub)]

14
compiler/rustc_query_system/src/query/caches.rs
View file

@ -2,8 +2,7 @@ use std::fmt::Debug;
use std::hash::Hash;
use std::sync::OnceLock;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sharded::{self, Sharded};
use rustc_data_structures::sharded::ShardedHashMap;
pub use rustc_data_structures::vec_cache::VecCache;
use rustc_hir::def_id::LOCAL_CRATE;
use rustc_index::Idx;
@ -36,7 +35,7 @@ pub trait QueryCache: Sized {
/// In-memory cache for queries whose keys aren't suitable for any of the
/// more specialized kinds of cache. Backed by a sharded hashmap.
pub struct DefaultCache<K, V> {
cache: Sharded<FxHashMap<K, (V, DepNodeIndex)>>,
cache: ShardedHashMap<K, (V, DepNodeIndex)>,
}
impl<K, V> Default for DefaultCache<K, V> {
@ -55,19 +54,14 @@ where
#[inline(always)]
fn lookup(&self, key: &K) -> Option<(V, DepNodeIndex)> {
let key_hash = sharded::make_hash(key);
let lock = self.cache.lock_shard_by_hash(key_hash);
let result = lock.raw_entry().from_key_hashed_nocheck(key_hash, key);
if let Some((_, value)) = result { Some(*value) } else { None }
self.cache.get(key)
}
#[inline]
fn complete(&self, key: K, value: V, index: DepNodeIndex) {
let mut lock = self.cache.lock_shard_by_value(&key);
// We may be overwriting another value. This is all right, since the dep-graph
// will check that the fingerprint matches.
lock.insert(key, (value, index));
self.cache.insert(key, (value, index));
}
fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {