Struct VecCache 

pub struct VecCache<K, V, I>
where
    K: Idx,
{
    buckets: [AtomicPtr<Slot<V>>; 21],
    present: [AtomicPtr<Slot<()>>; 21],
    len: AtomicUsize,
    key: PhantomData<(K, I)>,
}

In-memory cache for queries whose keys are densely-numbered IDs (e.g CrateNum, LocalDefId), and can therefore be used as indices into a dense vector of cached values.

(As of #124780 the underlying storage is not an actual Vec, but rather a series of increasingly-large buckets, for improved performance when the parallel frontend is using multiple threads.)

Each entry in the cache stores the query’s return value (V), and also an associated index (I), which in practice is a DepNodeIndex used for query dependency tracking.

Fields

buckets: [AtomicPtr<Slot<V>>; 21]

present: [AtomicPtr<Slot<()>>; 21]

len: AtomicUsize

key: PhantomData<(K, I)>

Implementations

impl<K, V, I> VecCache<K, V, I>

where K: Eq + Idx + Copy + Debug, V: Copy, I: Idx + Copy,

pub fn lookup(&self, key: &K) -> Option<(V, I)>

pub fn complete(&self, key: K, value: V, index: I)

pub fn iter(&self, f: &mut dyn FnMut(&K, &V, I))

Trait Implementations

impl<K, V, I> Default for VecCache<K, V, I>

where K: Idx,

fn default() -> VecCache<K, V, I>

Returns the “default value” for a type.

impl<K, V, I> Drop for VecCache<K, V, I>

where K: Idx,

fn drop(&mut self)

Executes the destructor for this type.

impl<K, V> QueryCache for VecCache<K, V, DepNodeIndex>

where K: Idx + Eq + Hash + Copy + Debug, V: Copy,

type Key = K

type Value = V

fn lookup(&self, key: &K) -> Option<(V, DepNodeIndex)>

Returns the cached value (and other information) associated with the given key, if it is present in the cache.

fn complete(&self, key: K, value: V, index: DepNodeIndex)

Adds a key/value entry to this cache.

fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex))

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 344 bytes