Factor query arena allocation out from query caches

3 files changed, 33 insertions, 196 deletions

diff --git a/compiler/rustc_query_system/src/query/caches.rs b/compiler/rustc_query_system/src/query/caches.rs
index 81c7e4673d4..e840108bdd8 100644
--- a/compiler/rustc_query_system/src/query/caches.rs
+++ b/compiler/rustc_query_system/src/query/caches.rs
@@ -1,12 +1,10 @@
 use crate::dep_graph::DepNodeIndex;
 
-use rustc_arena::TypedArena;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sharded;
 #[cfg(parallel_compiler)]
 use rustc_data_structures::sharded::Sharded;
 use rustc_data_structures::sync::Lock;
-use rustc_data_structures::sync::WorkerLocal;
 use rustc_index::vec::{Idx, IndexVec};
 use std::fmt::Debug;
 use std::hash::Hash;
@@ -16,12 +14,10 @@ pub trait CacheSelector<'tcx, V> {
     type Cache
     where
         V: Copy;
-    type ArenaCache;
 }
 
 pub trait QueryStorage {
-    type Value: Debug;
-    type Stored: Copy;
+    type Value: Copy;
 }
 
 pub trait QueryCache: QueryStorage + Sized {
@@ -31,9 +27,9 @@ pub trait QueryCache: QueryStorage + Sized {
     /// It returns the shard index and a lock guard to the shard,
     /// which will be used if the query is not in the cache and we need
     /// to compute it.
-    fn lookup(&self, key: &Self::Key) -> Option<(Self::Stored, DepNodeIndex)>;
+    fn lookup(&self, key: &Self::Key) -> Option<(Self::Value, DepNodeIndex)>;
 
-    fn complete(&self, key: Self::Key, value: Self::Value, index: DepNodeIndex) -> Self::Stored;
+    fn complete(&self, key: Self::Key, value: Self::Value, index: DepNodeIndex);
 
     fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex));
 }
@@ -44,7 +40,6 @@ impl<'tcx, K: Eq + Hash, V: 'tcx> CacheSelector<'tcx, V> for DefaultCacheSelecto
     type Cache = DefaultCache<K, V>
     where
         V: Copy;
-    type ArenaCache = ArenaCache<'tcx, K, V>;
 }
 
 pub struct DefaultCache<K, V> {
@@ -62,7 +57,6 @@ impl<K, V> Default for DefaultCache<K, V> {
 
 impl<K: Eq + Hash, V: Copy + Debug> QueryStorage for DefaultCache<K, V> {
     type Value = V;
-    type Stored = V;
 }
 
 impl<K, V> QueryCache for DefaultCache<K, V>
@@ -85,7 +79,7 @@ where
     }
 
     #[inline]
-    fn complete(&self, key: K, value: V, index: DepNodeIndex) -> Self::Stored {
+    fn complete(&self, key: K, value: V, index: DepNodeIndex) {
         #[cfg(parallel_compiler)]
         let mut lock = self.cache.get_shard_by_value(&key).lock();
         #[cfg(not(parallel_compiler))]
@@ -93,7 +87,6 @@ where
         // 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));
-        value
     }
 
     fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {
@@ -122,7 +115,6 @@ impl<'tcx, V: 'tcx> CacheSelector<'tcx, V> for SingleCacheSelector {
     type Cache = SingleCache<V>
     where
         V: Copy;
-    type ArenaCache = ArenaCache<'tcx, (), V>;
 }
 
 pub struct SingleCache<V> {
@@ -137,7 +129,6 @@ impl<V> Default for SingleCache<V> {
 
 impl<V: Copy + Debug> QueryStorage for SingleCache<V> {
     type Value = V;
-    type Stored = V;
 }
 
 impl<V> QueryCache for SingleCache<V>
@@ -152,9 +143,8 @@ where
     }
 
     #[inline]
-    fn complete(&self, _key: (), value: V, index: DepNodeIndex) -> Self::Stored {
+    fn complete(&self, _key: (), value: V, index: DepNodeIndex) {
         *self.cache.lock() = Some((value, index));
-        value
     }
 
     fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {
@@ -162,85 +152,12 @@ where
     }
 }
 
-pub struct ArenaCache<'tcx, K, V> {
-    arena: WorkerLocal<TypedArena<(V, DepNodeIndex)>>,
-    #[cfg(parallel_compiler)]
-    cache: Sharded<FxHashMap<K, &'tcx (V, DepNodeIndex)>>,
-    #[cfg(not(parallel_compiler))]
-    cache: Lock<FxHashMap<K, &'tcx (V, DepNodeIndex)>>,
-}
-
-impl<'tcx, K, V> Default for ArenaCache<'tcx, K, V> {
-    fn default() -> Self {
-        ArenaCache { arena: WorkerLocal::new(|_| TypedArena::default()), cache: Default::default() }
-    }
-}
-
-impl<'tcx, K: Eq + Hash, V: Debug + 'tcx> QueryStorage for ArenaCache<'tcx, K, V> {
-    type Value = V;
-    type Stored = &'tcx V;
-}
-
-impl<'tcx, K, V: 'tcx> QueryCache for ArenaCache<'tcx, K, V>
-where
-    K: Eq + Hash + Clone + Debug,
-    V: Debug,
-{
-    type Key = K;
-
-    #[inline(always)]
-    fn lookup(&self, key: &K) -> Option<(&'tcx V, DepNodeIndex)> {
-        let key_hash = sharded::make_hash(key);
-        #[cfg(parallel_compiler)]
-        let lock = self.cache.get_shard_by_hash(key_hash).lock();
-        #[cfg(not(parallel_compiler))]
-        let lock = self.cache.lock();
-        let result = lock.raw_entry().from_key_hashed_nocheck(key_hash, key);
-
-        if let Some((_, value)) = result { Some((&value.0, value.1)) } else { None }
-    }
-
-    #[inline]
-    fn complete(&self, key: K, value: V, index: DepNodeIndex) -> Self::Stored {
-        let value = self.arena.alloc((value, index));
-        let value = unsafe { &*(value as *const _) };
-        #[cfg(parallel_compiler)]
-        let mut lock = self.cache.get_shard_by_value(&key).lock();
-        #[cfg(not(parallel_compiler))]
-        let mut lock = self.cache.lock();
-        // We may be overwriting another value. This is all right, since the dep-graph
-        // will check that the fingerprint matches.
-        lock.insert(key, value);
-        &value.0
-    }
-
-    fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {
-        #[cfg(parallel_compiler)]
-        {
-            let shards = self.cache.lock_shards();
-            for shard in shards.iter() {
-                for (k, v) in shard.iter() {
-                    f(k, &v.0, v.1);
-                }
-            }
-        }
-        #[cfg(not(parallel_compiler))]
-        {
-            let map = self.cache.lock();
-            for (k, v) in map.iter() {
-                f(k, &v.0, v.1);
-            }
-        }
-    }
-}
-
 pub struct VecCacheSelector<K>(PhantomData<K>);
 
 impl<'tcx, K: Idx, V: 'tcx> CacheSelector<'tcx, V> for VecCacheSelector<K> {
     type Cache = VecCache<K, V>
     where
         V: Copy;
-    type ArenaCache = VecArenaCache<'tcx, K, V>;
 }
 
 pub struct VecCache<K: Idx, V> {
@@ -258,7 +175,6 @@ impl<K: Idx, V> Default for VecCache<K, V> {
 
 impl<K: Eq + Idx, V: Copy + Debug> QueryStorage for VecCache<K, V> {
     type Value = V;
-    type Stored = V;
 }
 
 impl<K, V> QueryCache for VecCache<K, V>
@@ -278,87 +194,12 @@ where
     }
 
     #[inline]
-    fn complete(&self, key: K, value: V, index: DepNodeIndex) -> Self::Stored {
+    fn complete(&self, key: K, value: V, index: DepNodeIndex) {
         #[cfg(parallel_compiler)]
         let mut lock = self.cache.get_shard_by_hash(key.index() as u64).lock();
         #[cfg(not(parallel_compiler))]
         let mut lock = self.cache.lock();
         lock.insert(key, (value, index));
-        value
-    }
-
-    fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {
-        #[cfg(parallel_compiler)]
-        {
-            let shards = self.cache.lock_shards();
-            for shard in shards.iter() {
-                for (k, v) in shard.iter_enumerated() {
-                    if let Some(v) = v {
-                        f(&k, &v.0, v.1);
-                    }
-                }
-            }
-        }
-        #[cfg(not(parallel_compiler))]
-        {
-            let map = self.cache.lock();
-            for (k, v) in map.iter_enumerated() {
-                if let Some(v) = v {
-                    f(&k, &v.0, v.1);
-                }
-            }
-        }
-    }
-}
-
-pub struct VecArenaCache<'tcx, K: Idx, V> {
-    arena: WorkerLocal<TypedArena<(V, DepNodeIndex)>>,
-    #[cfg(parallel_compiler)]
-    cache: Sharded<IndexVec<K, Option<&'tcx (V, DepNodeIndex)>>>,
-    #[cfg(not(parallel_compiler))]
-    cache: Lock<IndexVec<K, Option<&'tcx (V, DepNodeIndex)>>>,
-}
-
-impl<'tcx, K: Idx, V> Default for VecArenaCache<'tcx, K, V> {
-    fn default() -> Self {
-        VecArenaCache {
-            arena: WorkerLocal::new(|_| TypedArena::default()),
-            cache: Default::default(),
-        }
-    }
-}
-
-impl<'tcx, K: Eq + Idx, V: Debug + 'tcx> QueryStorage for VecArenaCache<'tcx, K, V> {
-    type Value = V;
-    type Stored = &'tcx V;
-}
-
-impl<'tcx, K, V: 'tcx> QueryCache for VecArenaCache<'tcx, K, V>
-where
-    K: Eq + Idx + Clone + Debug,
-    V: Debug,
-{
-    type Key = K;
-
-    #[inline(always)]
-    fn lookup(&self, key: &K) -> Option<(&'tcx V, DepNodeIndex)> {
-        #[cfg(parallel_compiler)]
-        let lock = self.cache.get_shard_by_hash(key.index() as u64).lock();
-        #[cfg(not(parallel_compiler))]
-        let lock = self.cache.lock();
-        if let Some(Some(value)) = lock.get(*key) { Some((&value.0, value.1)) } else { None }
-    }
-
-    #[inline]
-    fn complete(&self, key: K, value: V, index: DepNodeIndex) -> Self::Stored {
-        let value = self.arena.alloc((value, index));
-        let value = unsafe { &*(value as *const _) };
-        #[cfg(parallel_compiler)]
-        let mut lock = self.cache.get_shard_by_hash(key.index() as u64).lock();
-        #[cfg(not(parallel_compiler))]
-        let mut lock = self.cache.lock();
-        lock.insert(key, value);
-        &value.0
     }
 
     fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {
diff --git a/compiler/rustc_query_system/src/query/config.rs b/compiler/rustc_query_system/src/query/config.rs
index a28e45a5c08..925102d4b1e 100644
--- a/compiler/rustc_query_system/src/query/config.rs
+++ b/compiler/rustc_query_system/src/query/config.rs
@@ -20,10 +20,9 @@ pub trait QueryConfig<Qcx: QueryContext> {
     const NAME: &'static str;
 
     type Key: DepNodeParams<Qcx::DepContext> + Eq + Hash + Clone + Debug;
-    type Value: Debug;
-    type Stored: Debug + Copy + std::borrow::Borrow<Self::Value>;
+    type Value: Debug + Copy;
 
-    type Cache: QueryCache<Key = Self::Key, Stored = Self::Stored, Value = Self::Value>;
+    type Cache: QueryCache<Key = Self::Key, Value = Self::Value>;
 
     // Don't use this method to access query results, instead use the methods on TyCtxt
     fn query_state<'a>(tcx: Qcx) -> &'a QueryState<Self::Key, Qcx::DepKind>
@@ -38,9 +37,9 @@ pub trait QueryConfig<Qcx: QueryContext> {
     fn cache_on_disk(tcx: Qcx::DepContext, key: &Self::Key) -> bool;
 
     // Don't use this method to compute query results, instead use the methods on TyCtxt
-    fn execute_query(tcx: Qcx::DepContext, k: Self::Key) -> Self::Stored;
+    fn execute_query(tcx: Qcx::DepContext, k: Self::Key) -> Self::Value;
 
-    fn compute(tcx: Qcx, key: &Self::Key) -> fn(Qcx::DepContext, Self::Key) -> Self::Value;
+    fn compute(tcx: Qcx::DepContext, key: Self::Key) -> Self::Value;
 
     fn try_load_from_disk(qcx: Qcx, idx: &Self::Key) -> TryLoadFromDisk<Qcx, Self>;
 
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index ed66d1929c5..44e74844fde 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -246,7 +246,7 @@ where
 
     /// Completes the query by updating the query cache with the `result`,
     /// signals the waiter and forgets the JobOwner, so it won't poison the query
-    fn complete<C>(self, cache: &C, result: C::Value, dep_node_index: DepNodeIndex) -> C::Stored
+    fn complete<C>(self, cache: &C, result: C::Value, dep_node_index: DepNodeIndex)
     where
         C: QueryCache<Key = K>,
     {
@@ -257,23 +257,22 @@ where
         // Forget ourself so our destructor won't poison the query
         mem::forget(self);
 
-        let (job, result) = {
-            let job = {
-                #[cfg(parallel_compiler)]
-                let mut lock = state.active.get_shard_by_value(&key).lock();
-                #[cfg(not(parallel_compiler))]
-                let mut lock = state.active.lock();
-                match lock.remove(&key).unwrap() {
-                    QueryResult::Started(job) => job,
-                    QueryResult::Poisoned => panic!(),
-                }
-            };
-            let result = cache.complete(key, result, dep_node_index);
-            (job, result)
+        // Mark as complete before we remove the job from the active state
+        // so no other thread can re-execute this query.
+        cache.complete(key.clone(), result, dep_node_index);
+
+        let job = {
+            #[cfg(parallel_compiler)]
+            let mut lock = state.active.get_shard_by_value(&key).lock();
+            #[cfg(not(parallel_compiler))]
+            let mut lock = state.active.lock();
+            match lock.remove(&key).unwrap() {
+                QueryResult::Started(job) => job,
+                QueryResult::Poisoned => panic!(),
+            }
         };
 
         job.signal_complete();
-        result
     }
 }
 
@@ -336,7 +335,7 @@ where
 /// which will be used if the query is not in the cache and we need
 /// to compute it.
 #[inline]
-pub fn try_get_cached<Tcx, C>(tcx: Tcx, cache: &C, key: &C::Key) -> Option<C::Stored>
+pub fn try_get_cached<Tcx, C>(tcx: Tcx, cache: &C, key: &C::Key) -> Option<C::Value>
 where
     C: QueryCache,
     Tcx: DepContext,
@@ -358,7 +357,7 @@ fn try_execute_query<Q, Qcx>(
     span: Span,
     key: Q::Key,
     dep_node: Option<DepNode<Qcx::DepKind>>,
-) -> (Q::Stored, Option<DepNodeIndex>)
+) -> (Q::Value, Option<DepNodeIndex>)
 where
     Q: QueryConfig<Qcx>,
     Qcx: QueryContext,
@@ -390,7 +389,7 @@ where
                     );
                 }
             }
-            let result = job.complete(cache, result, dep_node_index);
+            job.complete(cache, result, dep_node_index);
             (result, Some(dep_node_index))
         }
         TryGetJob::Cycle(error) => {
@@ -426,9 +425,8 @@ where
     // Fast path for when incr. comp. is off.
     if !dep_graph.is_fully_enabled() {
         let prof_timer = qcx.dep_context().profiler().query_provider();
-        let result = qcx.start_query(job_id, Q::DEPTH_LIMIT, None, || {
-            Q::compute(qcx, &key)(*qcx.dep_context(), key)
-        });
+        let result =
+            qcx.start_query(job_id, Q::DEPTH_LIMIT, None, || Q::compute(*qcx.dep_context(), key));
         let dep_node_index = dep_graph.next_virtual_depnode_index();
         prof_timer.finish_with_query_invocation_id(dep_node_index.into());
         return (result, dep_node_index);
@@ -455,7 +453,7 @@ where
         qcx.start_query(job_id, Q::DEPTH_LIMIT, Some(&diagnostics), || {
             if Q::ANON {
                 return dep_graph.with_anon_task(*qcx.dep_context(), Q::DEP_KIND, || {
-                    Q::compute(qcx, &key)(*qcx.dep_context(), key)
+                    Q::compute(*qcx.dep_context(), key)
                 });
             }
 
@@ -463,8 +461,7 @@ where
             let dep_node =
                 dep_node_opt.unwrap_or_else(|| Q::construct_dep_node(*qcx.dep_context(), &key));
 
-            let task = Q::compute(qcx, &key);
-            dep_graph.with_task(dep_node, *qcx.dep_context(), key, task, Q::HASH_RESULT)
+            dep_graph.with_task(dep_node, *qcx.dep_context(), key, Q::compute, Q::HASH_RESULT)
         });
 
     prof_timer.finish_with_query_invocation_id(dep_node_index.into());
@@ -555,7 +552,7 @@ where
     let prof_timer = qcx.dep_context().profiler().query_provider();
 
     // The dep-graph for this computation is already in-place.
-    let result = dep_graph.with_ignore(|| Q::compute(qcx, key)(*qcx.dep_context(), key.clone()));
+    let result = dep_graph.with_ignore(|| Q::compute(*qcx.dep_context(), key.clone()));
 
     prof_timer.finish_with_query_invocation_id(dep_node_index.into());
 
@@ -727,7 +724,7 @@ pub enum QueryMode {
     Ensure,
 }
 
-pub fn get_query<Q, Qcx, D>(qcx: Qcx, span: Span, key: Q::Key, mode: QueryMode) -> Option<Q::Stored>
+pub fn get_query<Q, Qcx, D>(qcx: Qcx, span: Span, key: Q::Key, mode: QueryMode) -> Option<Q::Value>
 where
     D: DepKind,
     Q: QueryConfig<Qcx>,