Generalize query side effect handling to make future additions easier

Author: oli-obk

compiler/rustc_interface/src/callbacks.rs

@@ -32,8 +32,10 @@ fn track_span_parent(def_id: rustc_span::def_id::LocalDefId) {
 fn track_diagnostic(diagnostic: Diagnostic, f: &mut dyn FnMut(Diagnostic)) {
     tls::with_context_opt(|icx| {
         if let Some(icx) = icx {
-            if let Some(diagnostics) = icx.diagnostics {
-                diagnostics.lock().extend(Some(diagnostic.clone()));
+            if let Some(side_effects) = icx.side_effects {
+                let mut side_effects = side_effects.lock();
+                side_effects.diagnostics.push(diagnostic.clone());
+                std::mem::drop(side_effects);
             }
 
             // Diagnostics are tracked, we can ignore the dependency.

compiler/rustc_middle/src/ty/context/tls.rs

@@ -3,12 +3,11 @@ use super::{GlobalCtxt, TyCtxt};
 use crate::dep_graph::TaskDepsRef;
 use crate::query::plumbing::QueryJobId;
 use rustc_data_structures::sync::{self, Lock};
-use rustc_errors::Diagnostic;
+use rustc_query_system::query::QuerySideEffects;
 #[cfg(not(parallel_compiler))]
 use std::cell::Cell;
 use std::mem;
 use std::ptr;
-use thin_vec::ThinVec;
 
 /// This is the implicit state of rustc. It contains the current
 /// `TyCtxt` and query. It is updated when creating a local interner or
@@ -26,7 +25,7 @@ pub struct ImplicitCtxt<'a, 'tcx> {
 
     /// Where to store diagnostics for the current query job, if any.
     /// This is updated by `JobOwner::start` in `ty::query::plumbing` when executing a query.
-    pub diagnostics: Option<&'a Lock<ThinVec<Diagnostic>>>,
+    pub side_effects: Option<&'a Lock<QuerySideEffects>>,
 
     /// Used to prevent queries from calling too deeply.
     pub query_depth: usize,
@@ -42,7 +41,7 @@ impl<'a, 'tcx> ImplicitCtxt<'a, 'tcx> {
         ImplicitCtxt {
             tcx,
             query: None,
-            diagnostics: None,
+            side_effects: None,
             query_depth: 0,
             task_deps: TaskDepsRef::Ignore,
         }

compiler/rustc_query_impl/src/plumbing.rs

@@ -7,7 +7,6 @@ use crate::rustc_middle::ty::TyEncoder;
 use crate::QueryConfigRestored;
 use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
 use rustc_data_structures::sync::Lock;
-use rustc_errors::Diagnostic;
 
 use rustc_index::Idx;
 use rustc_middle::dep_graph::dep_kinds;
@@ -31,7 +30,6 @@ use rustc_serialize::Encodable;
 use rustc_session::Limit;
 use rustc_span::def_id::LOCAL_CRATE;
 use std::num::NonZeroU64;
-use thin_vec::ThinVec;
 
 #[derive(Copy, Clone)]
 pub struct QueryCtxt<'tcx> {
@@ -127,7 +125,7 @@ impl QueryContext for QueryCtxt<'_> {
         self,
         token: QueryJobId,
         depth_limit: bool,
-        diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
+        side_effects: Option<&Lock<QuerySideEffects>>,
         compute: impl FnOnce() -> R,
     ) -> R {
         // The `TyCtxt` stored in TLS has the same global interner lifetime
@@ -142,7 +140,7 @@ impl QueryContext for QueryCtxt<'_> {
             let new_icx = ImplicitCtxt {
                 tcx: self.tcx,
                 query: Some(token),
-                diagnostics,
+                side_effects,
                 query_depth: current_icx.query_depth + depth_limit as usize,
                 task_deps: current_icx.task_deps,
             };
@@ -174,6 +172,16 @@ impl QueryContext for QueryCtxt<'_> {
             crate_name: self.crate_name(LOCAL_CRATE),
         });
     }
+
+    #[tracing::instrument(level = "trace", skip(self))]
+    fn apply_side_effects(self, side_effects: QuerySideEffects) {
+        let dcx = self.dep_context().sess().dcx();
+        let QuerySideEffects { diagnostics } = side_effects;
+
+        for diagnostic in diagnostics {
+            dcx.emit_diagnostic(diagnostic);
+        }
+    }
 }
 
 pub(super) fn try_mark_green<'tcx>(tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool {

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -923,11 +923,7 @@ impl<D: Deps> DepGraphData<D> {
             // Promote the previous diagnostics to the current session.
             qcx.store_side_effects(dep_node_index, side_effects.clone());
 
-            let dcx = qcx.dep_context().sess().dcx();
-
-            for diagnostic in side_effects.diagnostics {
-                dcx.emit_diagnostic(diagnostic);
-            }
+            qcx.apply_side_effects(side_effects);
         }
     }
 }

compiler/rustc_query_system/src/query/mod.rs

@@ -89,7 +89,7 @@ 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>,
+    pub diagnostics: ThinVec<Diagnostic>,
 }
 
 impl QuerySideEffects {
@@ -121,6 +121,9 @@ pub trait QueryContext: HasDepContext {
     /// Register diagnostics for the given node, for use in next session.
     fn store_side_effects(self, dep_node_index: DepNodeIndex, side_effects: QuerySideEffects);
 
+    /// Actually execute the side effects
+    fn apply_side_effects(self, side_effects: QuerySideEffects);
+
     /// Register diagnostics for the given node, for use in next session.
     fn store_side_effects_for_anon_node(
         self,
@@ -135,7 +138,7 @@ pub trait QueryContext: HasDepContext {
         self,
         token: QueryJobId,
         depth_limit: bool,
-        diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
+        side_effects: Option<&Lock<QuerySideEffects>>,
         compute: impl FnOnce() -> R,
     ) -> R;
 

compiler/rustc_query_system/src/query/plumbing.rs

@@ -26,7 +26,6 @@ use std::collections::hash_map::Entry;
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::mem;
-use thin_vec::ThinVec;
 
 use super::QueryConfig;
 
@@ -513,10 +512,10 @@ where
     }
 
     let prof_timer = qcx.dep_context().profiler().query_provider();
-    let diagnostics = Lock::new(ThinVec::new());
+    let side_effects = Lock::new(QuerySideEffects::default());
 
     let (result, dep_node_index) =
-        qcx.start_query(job_id, query.depth_limit(), Some(&diagnostics), || {
+        qcx.start_query(job_id, query.depth_limit(), Some(&side_effects), || {
             if query.anon() {
                 return dep_graph_data.with_anon_task(*qcx.dep_context(), query.dep_kind(), || {
                     query.compute(qcx, key)
@@ -538,7 +537,7 @@ where
 
     prof_timer.finish_with_query_invocation_id(dep_node_index.into());
 
-    let side_effects = QuerySideEffects { diagnostics: diagnostics.into_inner() };
+    let side_effects = side_effects.into_inner();
 
     if std::intrinsics::unlikely(side_effects.maybe_any()) {
         if query.anon() {