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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:59:35 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:59:35 +0000 |
commit | d1b2d29528b7794b41e66fc2136e395a02f8529b (patch) | |
tree | a4a17504b260206dec3cf55b2dca82929a348ac2 /compiler/rustc_middle/src/traits/solve/cache.rs | |
parent | Releasing progress-linux version 1.72.1+dfsg1-1~progress7.99u1. (diff) | |
download | rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.tar.xz rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.zip |
Merging upstream version 1.73.0+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_middle/src/traits/solve/cache.rs')
-rw-r--r-- | compiler/rustc_middle/src/traits/solve/cache.rs | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/traits/solve/cache.rs b/compiler/rustc_middle/src/traits/solve/cache.rs new file mode 100644 index 000000000..9898b0019 --- /dev/null +++ b/compiler/rustc_middle/src/traits/solve/cache.rs @@ -0,0 +1,100 @@ +use super::{CanonicalInput, QueryResult}; +use crate::ty::TyCtxt; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_data_structures::sync::Lock; +use rustc_query_system::cache::WithDepNode; +use rustc_query_system::dep_graph::DepNodeIndex; +use rustc_session::Limit; +/// The trait solver cache used by `-Ztrait-solver=next`. +/// +/// FIXME(@lcnr): link to some official documentation of how +/// this works. +#[derive(Default)] +pub struct EvaluationCache<'tcx> { + map: Lock<FxHashMap<CanonicalInput<'tcx>, CacheEntry<'tcx>>>, +} + +pub struct CacheData<'tcx> { + pub result: QueryResult<'tcx>, + pub reached_depth: usize, + pub encountered_overflow: bool, +} + +impl<'tcx> EvaluationCache<'tcx> { + /// Insert a final result into the global cache. + pub fn insert( + &self, + key: CanonicalInput<'tcx>, + reached_depth: usize, + did_overflow: bool, + cycle_participants: FxHashSet<CanonicalInput<'tcx>>, + dep_node: DepNodeIndex, + result: QueryResult<'tcx>, + ) { + let mut map = self.map.borrow_mut(); + let entry = map.entry(key).or_default(); + let data = WithDepNode::new(dep_node, result); + entry.cycle_participants.extend(cycle_participants); + if did_overflow { + entry.with_overflow.insert(reached_depth, data); + } else { + entry.success = Some(Success { data, reached_depth }); + } + } + + /// Try to fetch a cached result, checking the recursion limit + /// and handling root goals of coinductive cycles. + /// + /// If this returns `Some` the cache result can be used. + pub fn get( + &self, + tcx: TyCtxt<'tcx>, + key: CanonicalInput<'tcx>, + cycle_participant_in_stack: impl FnOnce(&FxHashSet<CanonicalInput<'tcx>>) -> bool, + available_depth: Limit, + ) -> Option<CacheData<'tcx>> { + let map = self.map.borrow(); + let entry = map.get(&key)?; + + if cycle_participant_in_stack(&entry.cycle_participants) { + return None; + } + + if let Some(ref success) = entry.success { + if available_depth.value_within_limit(success.reached_depth) { + return Some(CacheData { + result: success.data.get(tcx), + reached_depth: success.reached_depth, + encountered_overflow: false, + }); + } + } + + entry.with_overflow.get(&available_depth.0).map(|e| CacheData { + result: e.get(tcx), + reached_depth: available_depth.0, + encountered_overflow: true, + }) + } +} + +struct Success<'tcx> { + data: WithDepNode<QueryResult<'tcx>>, + reached_depth: usize, +} + +/// The cache entry for a goal `CanonicalInput`. +/// +/// This contains results whose computation never hit the +/// recursion limit in `success`, and all results which hit +/// the recursion limit in `with_overflow`. +#[derive(Default)] +struct CacheEntry<'tcx> { + success: Option<Success<'tcx>>, + /// We have to be careful when caching roots of cycles. + /// + /// See the doc comment of `StackEntry::cycle_participants` for more + /// details. + cycle_participants: FxHashSet<CanonicalInput<'tcx>>, + with_overflow: FxHashMap<usize, WithDepNode<QueryResult<'tcx>>>, +} |