1 files changed, 75 insertions, 0 deletions
diff --git a/compiler/rustc_query_system/src/query/config.rs b/compiler/rustc_query_system/src/query/config.rs
new file mode 100644
index 000000000..964914a13
--- /dev/null
+++ b/compiler/rustc_query_system/src/query/config.rs
@@ -0,0 +1,75 @@
+//! Query configuration and description traits.
+
+use crate::dep_graph::DepNode;
+use crate::dep_graph::SerializedDepNodeIndex;
+use crate::ich::StableHashingContext;
+use crate::query::caches::QueryCache;
+use crate::query::{QueryContext, QueryState};
+
+use rustc_data_structures::fingerprint::Fingerprint;
+use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
+use std::fmt::Debug;
+use std::hash::Hash;
+
+pub trait QueryConfig {
+    const NAME: &'static str;
+
+    type Key: Eq + Hash + Clone + Debug;
+    type Value;
+    type Stored: Clone;
+}
+
+pub struct QueryVTable<CTX: QueryContext, K, V> {
+    pub anon: bool,
+    pub dep_kind: CTX::DepKind,
+    pub eval_always: bool,
+    pub cache_on_disk: bool,
+
+    pub compute: fn(CTX::DepContext, K) -> V,
+    pub hash_result: Option<fn(&mut StableHashingContext<'_>, &V) -> Fingerprint>,
+    pub handle_cycle_error: fn(CTX, DiagnosticBuilder<'_, ErrorGuaranteed>) -> V,
+    pub try_load_from_disk: Option<fn(CTX, SerializedDepNodeIndex) -> Option<V>>,
+}
+
+impl<CTX: QueryContext, K, V> QueryVTable<CTX, K, V> {
+    pub(crate) fn to_dep_node(&self, tcx: CTX::DepContext, key: &K) -> DepNode<CTX::DepKind>
+    where
+        K: crate::dep_graph::DepNodeParams<CTX::DepContext>,
+    {
+        DepNode::construct(tcx, self.dep_kind, key)
+    }
+
+    pub(crate) fn compute(&self, tcx: CTX::DepContext, key: K) -> V {
+        (self.compute)(tcx, key)
+    }
+
+    pub(crate) fn try_load_from_disk(&self, tcx: CTX, index: SerializedDepNodeIndex) -> Option<V> {
+        self.try_load_from_disk
+            .expect("QueryDescription::load_from_disk() called for an unsupported query.")(
+            tcx, index,
+        )
+    }
+}
+
+pub trait QueryDescription<CTX: QueryContext>: QueryConfig {
+    const TRY_LOAD_FROM_DISK: Option<fn(CTX, SerializedDepNodeIndex) -> Option<Self::Value>>;
+
+    type Cache: QueryCache<Key = Self::Key, Stored = Self::Stored, Value = Self::Value>;
+
+    fn describe(tcx: CTX, key: Self::Key) -> String;
+
+    // Don't use this method to access query results, instead use the methods on TyCtxt
+    fn query_state<'a>(tcx: CTX) -> &'a QueryState<Self::Key>
+    where
+        CTX: 'a;
+
+    // Don't use this method to access query results, instead use the methods on TyCtxt
+    fn query_cache<'a>(tcx: CTX) -> &'a Self::Cache
+    where
+        CTX: 'a;
+
+    // Don't use this method to compute query results, instead use the methods on TyCtxt
+    fn make_vtable(tcx: CTX, key: &Self::Key) -> QueryVTable<CTX, Self::Key, Self::Value>;
+
+    fn cache_on_disk(tcx: CTX::DepContext, key: &Self::Key) -> bool;
+}