Avoiding calling queries when collecting active queries

Zoxc · Zoxc · commit 23c63a9d335b · 2025-03-26T09:17:13.000+01:00
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
@@ -18,7 +18,7 @@ use rustc_session::{EarlyDiagCtxt, Session, filesearch};
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::edition::Edition;
 use rustc_span::source_map::SourceMapInputs;
-use rustc_span::{Symbol, sym};
+use rustc_span::{SessionGlobals, Symbol, sym};
 use rustc_target::spec::Target;
 use tracing::info;
 
@@ -188,26 +188,11 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce(CurrentGcx) -> R + Send,
             // On deadlock, creates a new thread and forwards information in thread
             // locals to it. The new thread runs the deadlock handler.
 
-            // Get a `GlobalCtxt` reference from `CurrentGcx` as we cannot rely on having a
-            // `TyCtxt` TLS reference here.
-            let query_map = current_gcx2.access(|gcx| {
-                tls::enter_context(&tls::ImplicitCtxt::new(gcx), || {
-                    tls::with(|tcx| {
-                        match QueryCtxt::new(tcx).collect_active_jobs() {
-                            Ok(query_map) => query_map,
-                            Err(_) => {
-                                // There was an unexpected error collecting all active jobs, which we need
-                                // to find cycles to break.
-                                // We want to avoid panicking in the deadlock handler, so we abort instead.
-                                eprintln!("internal compiler error: failed to get query map in deadlock handler, aborting process");
-                                process::abort();
-                            }
-                        }
-                    })
-                })
-            });
-            let query_map = FromDyn::from(query_map);
+            let current_gcx2 = current_gcx2.clone();
             let registry = rayon_core::Registry::current();
+            let session_globals = rustc_span::with_session_globals(|session_globals| {
+                session_globals as *const SessionGlobals as usize
+            });
             thread::Builder::new()
                 .name("rustc query cycle handler".to_string())
                 .spawn(move || {
@@ -217,7 +202,24 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce(CurrentGcx) -> R + Send,
                         // otherwise the compiler could just hang,
                         process::abort();
                     });
-                    break_query_cycles(query_map.into_inner(), &registry);
+
+                    // Get a `GlobalCtxt` reference from `CurrentGcx` as we cannot rely on having a
+                    // `TyCtxt` TLS reference here.
+                    current_gcx2.access(|gcx| {
+                        tls::enter_context(&tls::ImplicitCtxt::new(gcx), || {
+                            tls::with(|tcx| {
+                                // Accessing session globals is sound as they outlive `GlobalCtxt`.
+                                // They are needed to hash query keys containing spans or symbols.
+                                let query_map = rustc_span::set_session_globals_then(unsafe { &*(session_globals as *const SessionGlobals) }, || {
+                                    // Ensure there was no errors collecting all active jobs.
+                                    // We need the complete map to ensure we find a cycle to break.
+                                    QueryCtxt::new(tcx).collect_active_jobs().ok().expect("failed to collect active queries in deadlock handler")
+                                });
+                                break_query_cycles(query_map, &registry);
+                            })
+                        })
+                    });
+
                     on_panic.disable();
                 })
                 .unwrap();
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
@@ -30,7 +30,9 @@ use rustc_index::IndexVec;
 use rustc_lint_defs::LintId;
 use rustc_macros::rustc_queries;
 use rustc_query_system::ich::StableHashingContext;
-use rustc_query_system::query::{QueryCache, QueryMode, QueryState, try_get_cached};
+use rustc_query_system::query::{
+    QueryCache, QueryMode, QueryStackDeferred, QueryState, try_get_cached,
+};
 use rustc_session::Limits;
 use rustc_session::config::{EntryFnType, OptLevel, OutputFilenames, SymbolManglingVersion};
 use rustc_session::cstore::{
diff --git a/compiler/rustc_middle/src/query/plumbing.rs b/compiler/rustc_middle/src/query/plumbing.rs
@@ -488,7 +488,7 @@ macro_rules! define_callbacks {
         #[derive(Default)]
         pub struct QueryStates<'tcx> {
             $(
-                pub $name: QueryState<$($K)*>,
+                pub $name: QueryState<$($K)*, QueryStackDeferred<'tcx>>,
             )*
         }
 
diff --git a/compiler/rustc_middle/src/values.rs b/compiler/rustc_middle/src/values.rs
@@ -88,7 +88,7 @@ impl<'tcx> Value<TyCtxt<'tcx>> for Representability {
             if info.query.dep_kind == dep_kinds::representability
                 && let Some(field_id) = info.query.def_id
                 && let Some(field_id) = field_id.as_local()
-                && let Some(DefKind::Field) = info.query.def_kind
+                && let Some(DefKind::Field) = info.query.info.def_kind
             {
                 let parent_id = tcx.parent(field_id.to_def_id());
                 let item_id = match tcx.def_kind(parent_id) {
@@ -216,7 +216,7 @@ impl<'tcx, T> Value<TyCtxt<'tcx>> for Result<T, &'_ ty::layout::LayoutError<'_>>
                             continue;
                         };
                         let frame_span =
-                            frame.query.default_span(cycle[(i + 1) % cycle.len()].span);
+                            frame.query.info.default_span(cycle[(i + 1) % cycle.len()].span);
                         if frame_span.is_dummy() {
                             continue;
                         }
diff --git a/compiler/rustc_query_impl/src/lib.rs b/compiler/rustc_query_impl/src/lib.rs
@@ -26,8 +26,8 @@ use rustc_middle::ty::TyCtxt;
 use rustc_query_system::dep_graph::SerializedDepNodeIndex;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_query_system::query::{
-    CycleError, HashResult, QueryCache, QueryConfig, QueryMap, QueryMode, QueryState,
-    get_query_incr, get_query_non_incr,
+    CycleError, HashResult, QueryCache, QueryConfig, QueryMap, QueryMode, QueryStackDeferred,
+    QueryState, get_query_incr, get_query_non_incr,
 };
 use rustc_query_system::{HandleCycleError, Value};
 use rustc_span::{ErrorGuaranteed, Span};
@@ -84,7 +84,10 @@ where
     }
 
     #[inline(always)]
-    fn query_state<'a>(self, qcx: QueryCtxt<'tcx>) -> &'a QueryState<Self::Key>
+    fn query_state<'a>(
+        self,
+        qcx: QueryCtxt<'tcx>,
+    ) -> &'a QueryState<Self::Key, QueryStackDeferred<'tcx>>
     where
         QueryCtxt<'tcx>: 'a,
     {
@@ -93,7 +96,7 @@ where
         unsafe {
             &*(&qcx.tcx.query_system.states as *const QueryStates<'tcx>)
                 .byte_add(self.dynamic.query_state)
-                .cast::<QueryState<Self::Key>>()
+                .cast::<QueryState<Self::Key, QueryStackDeferred<'tcx>>>()
         }
     }
 
diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
@@ -3,8 +3,10 @@
 //! manage the caches, and so forth.
 
 use std::num::NonZero;
+use std::sync::Arc;
 
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_data_structures::unord::UnordMap;
 use rustc_hashes::Hash64;
 use rustc_index::Idx;
@@ -24,8 +26,8 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_query_system::dep_graph::{DepNodeParams, HasDepContext};
 use rustc_query_system::ich::StableHashingContext;
 use rustc_query_system::query::{
-    QueryCache, QueryConfig, QueryContext, QueryJobId, QueryMap, QuerySideEffect, QueryStackFrame,
-    force_query,
+    QueryCache, QueryConfig, QueryContext, QueryJobId, QueryMap, QuerySideEffect,
+    QueryStackDeferred, QueryStackFrame, QueryStackFrameExtra, force_query,
 };
 use rustc_query_system::{QueryOverflow, QueryOverflowNote};
 use rustc_serialize::{Decodable, Encodable};
@@ -65,7 +67,9 @@ impl<'tcx> HasDepContext for QueryCtxt<'tcx> {
     }
 }
 
-impl QueryContext for QueryCtxt<'_> {
+impl<'tcx> QueryContext for QueryCtxt<'tcx> {
+    type QueryInfo = QueryStackDeferred<'tcx>;
+
     #[inline]
     fn next_job_id(self) -> QueryJobId {
         QueryJobId(
@@ -82,7 +86,9 @@ impl QueryContext for QueryCtxt<'_> {
     /// Returns a query map representing active query jobs.
     /// It returns an incomplete map as an error if it fails
     /// to take locks.
-    fn collect_active_jobs(self) -> Result<QueryMap, QueryMap> {
+    fn collect_active_jobs(
+        self,
+    ) -> Result<QueryMap<QueryStackDeferred<'tcx>>, QueryMap<QueryStackDeferred<'tcx>>> {
         let mut jobs = QueryMap::default();
         let mut complete = true;
 
@@ -95,6 +101,13 @@ impl QueryContext for QueryCtxt<'_> {
         if complete { Ok(jobs) } else { Err(jobs) }
     }
 
+    fn lift_query_info(
+        self,
+        info: &QueryStackDeferred<'tcx>,
+    ) -> rustc_query_system::query::QueryStackFrameExtra {
+        info.extract()
+    }
+
     // Interactions with on_disk_cache
     fn load_side_effect(
         self,
@@ -159,7 +172,10 @@ impl QueryContext for QueryCtxt<'_> {
 
         self.sess.dcx().emit_fatal(QueryOverflow {
             span: info.job.span,
-            note: QueryOverflowNote { desc: info.query.description, depth },
+            note: QueryOverflowNote {
+                desc: self.lift_query_info(&info.query.info).description,
+                depth,
+            },
             suggested_limit,
             crate_name: self.crate_name(LOCAL_CRATE),
         });
@@ -298,39 +314,45 @@ macro_rules! should_ever_cache_on_disk {
 
 pub(crate) fn create_query_frame<
     'tcx,
-    K: Copy + Key + for<'a> HashStable<StableHashingContext<'a>>,
+    K: Copy + DynSend + DynSync + Key + for<'a> HashStable<StableHashingContext<'a>> + 'tcx,
 >(
     tcx: TyCtxt<'tcx>,
     do_describe: fn(TyCtxt<'tcx>, K) -> String,
     key: K,
     kind: DepKind,
     name: &'static str,
-) -> QueryStackFrame {
-    // If reduced queries are requested, we may be printing a query stack due
-    // to a panic. Avoid using `default_span` and `def_kind` in that case.
-    let reduce_queries = with_reduced_queries();
-
-    // Avoid calling queries while formatting the description
-    let description = ty::print::with_no_queries!(do_describe(tcx, key));
-    let description = if tcx.sess.verbose_internals() {
-        format!("{description} [{name:?}]")
-    } else {
-        description
-    };
-    let span = if kind == dep_graph::dep_kinds::def_span || reduce_queries {
-        // The `def_span` query is used to calculate `default_span`,
-        // so exit to avoid infinite recursion.
-        None
-    } else {
-        Some(key.default_span(tcx))
-    };
+) -> QueryStackFrame<QueryStackDeferred<'tcx>> {
     let def_id = key.key_as_def_id();
-    let def_kind = if kind == dep_graph::dep_kinds::def_kind || reduce_queries {
-        // Try to avoid infinite recursion.
-        None
-    } else {
-        def_id.and_then(|def_id| def_id.as_local()).map(|def_id| tcx.def_kind(def_id))
+
+    let extra = move || {
+        // If reduced queries are requested, we may be printing a query stack due
+        // to a panic. Avoid using `default_span` and `def_kind` in that case.
+        let reduce_queries = with_reduced_queries();
+
+        // Avoid calling queries while formatting the description
+        let description = ty::print::with_no_queries!(do_describe(tcx, key));
+        let description = if tcx.sess.verbose_internals() {
+            format!("{description} [{name:?}]")
+        } else {
+            description
+        };
+        let span = if kind == dep_graph::dep_kinds::def_span || reduce_queries {
+            // The `def_span` query is used to calculate `default_span`,
+            // so exit to avoid infinite recursion.
+            None
+        } else {
+            Some(key.default_span(tcx))
+        };
+
+        let def_kind = if kind == dep_graph::dep_kinds::def_kind || reduce_queries {
+            // Try to avoid infinite recursion.
+            None
+        } else {
+            def_id.and_then(|def_id| def_id.as_local()).map(|def_id| tcx.def_kind(def_id))
+        };
+        QueryStackFrameExtra::new(description, span, def_kind)
     };
+
     let hash = || {
         tcx.with_stable_hashing_context(|mut hcx| {
             let mut hasher = StableHasher::new();
@@ -341,7 +363,11 @@ pub(crate) fn create_query_frame<
     };
     let def_id_for_ty_in_cycle = key.def_id_for_ty_in_cycle();
 
-    QueryStackFrame::new(description, span, def_id, def_kind, kind, def_id_for_ty_in_cycle, hash)
+    // SAFETY: None of the captures in `extra` have destructors that access 'tcx
+    // as they don't have destructors.
+    let info = unsafe { QueryStackDeferred::new(Arc::new(extra)) };
+
+    QueryStackFrame::new(info, kind, hash, def_id, def_id_for_ty_in_cycle)
 }
 
 pub(crate) fn encode_query_results<'a, 'tcx, Q>(
@@ -688,7 +714,10 @@ macro_rules! define_queries {
                 }
             }
 
-            pub(crate) fn try_collect_active_jobs<'tcx>(tcx: TyCtxt<'tcx>, qmap: &mut QueryMap) -> Option<()> {
+            pub(crate) fn try_collect_active_jobs<'tcx>(
+                tcx: TyCtxt<'tcx>,
+                qmap: &mut QueryMap<QueryStackDeferred<'tcx>>,
+            ) -> Option<()> {
                 let make_query = |tcx, key| {
                     let kind = rustc_middle::dep_graph::dep_kinds::$name;
                     let name = stringify!($name);
@@ -768,7 +797,9 @@ macro_rules! define_queries {
 
         // These arrays are used for iteration and can't be indexed by `DepKind`.
 
-        const TRY_COLLECT_ACTIVE_JOBS: &[for<'tcx> fn(TyCtxt<'tcx>, &mut QueryMap) -> Option<()>] =
+        const TRY_COLLECT_ACTIVE_JOBS: &[
+            for<'tcx> fn(TyCtxt<'tcx>, &mut QueryMap<QueryStackDeferred<'tcx>>) -> Option<()>
+        ] =
             &[$(query_impl::$name::try_collect_active_jobs),*];
 
         const ALLOC_SELF_PROFILE_QUERY_STRINGS: &[
diff --git a/compiler/rustc_query_system/src/query/config.rs b/compiler/rustc_query_system/src/query/config.rs
@@ -6,6 +6,7 @@ use std::hash::Hash;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_span::ErrorGuaranteed;
 
+use super::QueryStackFrameExtra;
 use crate::dep_graph::{DepKind, DepNode, DepNodeParams, SerializedDepNodeIndex};
 use crate::error::HandleCycleError;
 use crate::ich::StableHashingContext;
@@ -27,7 +28,7 @@ pub trait QueryConfig<Qcx: QueryContext>: Copy {
     fn format_value(self) -> fn(&Self::Value) -> String;
 
     // Don't use this method to access query results, instead use the methods on TyCtxt
-    fn query_state<'a>(self, tcx: Qcx) -> &'a QueryState<Self::Key>
+    fn query_state<'a>(self, tcx: Qcx) -> &'a QueryState<Self::Key, Qcx::QueryInfo>
     where
         Qcx: 'a;
 
@@ -57,7 +58,7 @@ pub trait QueryConfig<Qcx: QueryContext>: Copy {
     fn value_from_cycle_error(
         self,
         tcx: Qcx::DepContext,
-        cycle_error: &CycleError,
+        cycle_error: &CycleError<QueryStackFrameExtra>,
         guar: ErrorGuaranteed,
     ) -> Self::Value;
 
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
diff --git a/compiler/rustc_query_system/src/query/mod.rs b/compiler/rustc_query_system/src/query/mod.rs
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs

Original file line number	Diff line number	Diff line change
`@@ -488,7 +488,7 @@ macro_rules! define_callbacks {`
`488`	`488`	`#[derive(Default)]`
`489`	`489`	`pub struct QueryStates<'tcx> {`
`490`	`490`	`$(`
`491`		`- pub $name: QueryState<$($K)*>,`
	`491`	`+ pub $name: QueryState<$($K)*, QueryStackDeferred<'tcx>>,`
`492`	`492`	`)*`
`493`	`493`	`}`
`494`	`494`