diff options
Diffstat (limited to 'compiler/rustc_middle/src/mir/graph_cyclic_cache.rs')
-rw-r--r-- | compiler/rustc_middle/src/mir/graph_cyclic_cache.rs | 63 |
1 files changed, 0 insertions, 63 deletions
diff --git a/compiler/rustc_middle/src/mir/graph_cyclic_cache.rs b/compiler/rustc_middle/src/mir/graph_cyclic_cache.rs deleted file mode 100644 index f97bf2883..000000000 --- a/compiler/rustc_middle/src/mir/graph_cyclic_cache.rs +++ /dev/null @@ -1,63 +0,0 @@ -use rustc_data_structures::graph::{ - self, DirectedGraph, WithNumNodes, WithStartNode, WithSuccessors, -}; -use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; -use rustc_data_structures::sync::OnceCell; -use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; - -/// Helper type to cache the result of `graph::is_cyclic`. -#[derive(Clone, Debug)] -pub(super) struct GraphIsCyclicCache { - cache: OnceCell<bool>, -} - -impl GraphIsCyclicCache { - #[inline] - pub(super) fn new() -> Self { - GraphIsCyclicCache { cache: OnceCell::new() } - } - - pub(super) fn is_cyclic<G>(&self, graph: &G) -> bool - where - G: ?Sized + DirectedGraph + WithStartNode + WithSuccessors + WithNumNodes, - { - *self.cache.get_or_init(|| graph::is_cyclic(graph)) - } - - /// Invalidates the cache. - #[inline] - pub(super) fn invalidate(&mut self) { - // Invalidating the cache requires mutating the MIR, which in turn requires a unique - // reference (`&mut`) to the `mir::Body`. Because of this, we can assume that all - // callers of `invalidate` have a unique reference to the MIR and thus to the - // cache. This means we never need to do synchronization when `invalidate` is called, - // we can simply reinitialize the `OnceCell`. - self.cache = OnceCell::new(); - } -} - -impl<S: Encoder> Encodable<S> for GraphIsCyclicCache { - #[inline] - fn encode(&self, s: &mut S) { - Encodable::encode(&(), s); - } -} - -impl<D: Decoder> Decodable<D> for GraphIsCyclicCache { - #[inline] - fn decode(d: &mut D) -> Self { - let () = Decodable::decode(d); - Self::new() - } -} - -impl<CTX> HashStable<CTX> for GraphIsCyclicCache { - #[inline] - fn hash_stable(&self, _: &mut CTX, _: &mut StableHasher) { - // do nothing - } -} - -TrivialTypeTraversalAndLiftImpls! { - GraphIsCyclicCache, -} |