1 use rustc_data_structures::indexed_vec::IndexVec;
2 use rustc_data_structures::sync::{RwLock, MappedReadGuard, ReadGuard};
3 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
5 use crate::ich::StableHashingContext;
6 use crate::mir::{Mir, BasicBlock};
8 use crate::rustc_serialize as serialize;
10 #[derive(Clone, Debug)]
12 predecessors: RwLock<Option<IndexVec<BasicBlock, Vec<BasicBlock>>>>
16 impl serialize::Encodable for Cache {
17 fn encode<S: serialize::Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
18 serialize::Encodable::encode(&(), s)
22 impl serialize::Decodable for Cache {
23 fn decode<D: serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
24 serialize::Decodable::decode(d).map(|_v: ()| Self::new())
28 impl<'a> HashStable<StableHashingContext<'a>> for Cache {
29 fn hash_stable<W: StableHasherResult>(&self,
30 _: &mut StableHashingContext<'a>,
31 _: &mut StableHasher<W>) {
37 pub fn new() -> Self {
39 predecessors: RwLock::new(None)
43 pub fn invalidate(&self) {
44 // FIXME: consider being more fine-grained
45 *self.predecessors.borrow_mut() = None;
51 ) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
52 if self.predecessors.borrow().is_none() {
53 *self.predecessors.borrow_mut() = Some(calculate_predecessors(mir));
56 ReadGuard::map(self.predecessors.borrow(), |p| p.as_ref().unwrap())
60 fn calculate_predecessors(mir: &Mir<'_>) -> IndexVec<BasicBlock, Vec<BasicBlock>> {
61 let mut result = IndexVec::from_elem(vec![], mir.basic_blocks());
62 for (bb, data) in mir.basic_blocks().iter_enumerated() {
63 if let Some(ref term) = data.terminator {
64 for &tgt in term.successors() {
73 CloneTypeFoldableAndLiftImpls! {