1 files changed, 125 insertions, 0 deletions
diff --git a/compiler/rustc_query_system/src/query/mod.rs b/compiler/rustc_query_system/src/query/mod.rs
new file mode 100644
index 000000000..fb2258434
--- /dev/null
+++ b/compiler/rustc_query_system/src/query/mod.rs
@@ -0,0 +1,125 @@
+mod plumbing;
+pub use self::plumbing::*;
+
+mod job;
+#[cfg(parallel_compiler)]
+pub use self::job::deadlock;
+pub use self::job::{print_query_stack, QueryInfo, QueryJob, QueryJobId, QueryJobInfo, QueryMap};
+
+mod caches;
+pub use self::caches::{
+    ArenaCacheSelector, CacheSelector, DefaultCacheSelector, QueryCache, QueryStorage,
+};
+
+mod config;
+pub use self::config::{QueryConfig, QueryDescription, QueryVTable};
+
+use crate::dep_graph::{DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
+
+use rustc_data_structures::sync::Lock;
+use rustc_data_structures::thin_vec::ThinVec;
+use rustc_errors::Diagnostic;
+use rustc_hir::def::DefKind;
+use rustc_span::Span;
+
+/// Description of a frame in the query stack.
+///
+/// This is mostly used in case of cycles for error reporting.
+#[derive(Clone, Debug)]
+pub struct QueryStackFrame {
+    pub name: &'static str,
+    pub description: String,
+    span: Option<Span>,
+    def_kind: Option<DefKind>,
+    /// This hash is used to deterministically pick
+    /// a query to remove cycles in the parallel compiler.
+    #[cfg(parallel_compiler)]
+    hash: u64,
+}
+
+impl QueryStackFrame {
+    #[inline]
+    pub fn new(
+        name: &'static str,
+        description: String,
+        span: Option<Span>,
+        def_kind: Option<DefKind>,
+        _hash: impl FnOnce() -> u64,
+    ) -> Self {
+        Self {
+            name,
+            description,
+            span,
+            def_kind,
+            #[cfg(parallel_compiler)]
+            hash: _hash(),
+        }
+    }
+
+    // FIXME(eddyb) Get more valid `Span`s on queries.
+    #[inline]
+    pub fn default_span(&self, span: Span) -> Span {
+        if !span.is_dummy() {
+            return span;
+        }
+        self.span.unwrap_or(span)
+    }
+}
+
+/// Tracks 'side effects' for a particular query.
+/// This struct is saved to disk along with the query result,
+/// and loaded from disk if we mark the query as green.
+/// This allows us to 'replay' changes to global state
+/// that would otherwise only occur if we actually
+/// executed the query method.
+#[derive(Debug, Clone, Default, Encodable, Decodable)]
+pub struct QuerySideEffects {
+    /// Stores any diagnostics emitted during query execution.
+    /// These diagnostics will be re-emitted if we mark
+    /// the query as green.
+    pub(super) diagnostics: ThinVec<Diagnostic>,
+}
+
+impl QuerySideEffects {
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        let QuerySideEffects { diagnostics } = self;
+        diagnostics.is_empty()
+    }
+    pub fn append(&mut self, other: QuerySideEffects) {
+        let QuerySideEffects { diagnostics } = self;
+        diagnostics.extend(other.diagnostics);
+    }
+}
+
+pub trait QueryContext: HasDepContext {
+    fn next_job_id(&self) -> QueryJobId;
+
+    /// Get the query information from the TLS context.
+    fn current_query_job(&self) -> Option<QueryJobId>;
+
+    fn try_collect_active_jobs(&self) -> Option<QueryMap>;
+
+    /// Load side effects associated to the node in the previous session.
+    fn load_side_effects(&self, prev_dep_node_index: SerializedDepNodeIndex) -> QuerySideEffects;
+
+    /// Register diagnostics for the given node, for use in next session.
+    fn store_side_effects(&self, dep_node_index: DepNodeIndex, side_effects: QuerySideEffects);
+
+    /// Register diagnostics for the given node, for use in next session.
+    fn store_side_effects_for_anon_node(
+        &self,
+        dep_node_index: DepNodeIndex,
+        side_effects: QuerySideEffects,
+    );
+
+    /// Executes a job by changing the `ImplicitCtxt` to point to the
+    /// new query job while it executes. It returns the diagnostics
+    /// captured during execution and the actual result.
+    fn start_query<R>(
+        &self,
+        token: QueryJobId,
+        diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
+        compute: impl FnOnce() -> R,
+    ) -> R;
+}