diff options
Diffstat (limited to 'compiler/rustc_data_structures')
| -rw-r--r-- | compiler/rustc_data_structures/src/vec_cache.rs | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/vec_cache.rs b/compiler/rustc_data_structures/src/vec_cache.rs index eb251b587c8..2ff60ab7f36 100644 --- a/compiler/rustc_data_structures/src/vec_cache.rs +++ b/compiler/rustc_data_structures/src/vec_cache.rs @@ -206,6 +206,19 @@ impl SlotIndex { } } +/// 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. +/// +/// [#124780]: https://github.com/rust-lang/rust/pull/124780 pub struct VecCache<K: Idx, V, I> { // Entries per bucket: // Bucket 0: 4096 2^12 |