diff --git a/compiler/rustc_middle/src/ty/context/tls.rs b/compiler/rustc_middle/src/ty/context/tls.rs index fa9995898ac20..a06f927928205 100644 --- a/compiler/rustc_middle/src/ty/context/tls.rs +++ b/compiler/rustc_middle/src/ty/context/tls.rs @@ -16,8 +16,7 @@ pub struct ImplicitCtxt<'a, 'tcx> { /// The current `TyCtxt`. pub tcx: TyCtxt<'tcx>, - /// The current query job, if any. This is updated by `JobOwner::start` in - /// `ty::query::plumbing` when executing a query. + /// The current query job, if any. pub query: Option, /// Used to prevent queries from calling too deeply. diff --git a/compiler/rustc_query_impl/src/execution.rs b/compiler/rustc_query_impl/src/execution.rs index e58e626a7dfae..1bfd1d702888f 100644 --- a/compiler/rustc_query_impl/src/execution.rs +++ b/compiler/rustc_query_impl/src/execution.rs @@ -83,14 +83,18 @@ pub(crate) fn gather_active_jobs_inner<'tcx, K: Copy>( Some(()) } -/// A type representing the responsibility to execute the job in the `job` field. -/// This will poison the relevant query if dropped. -struct JobOwner<'tcx, K> +/// Guard object representing the responsibility to execute a query job and +/// mark it as completed. +/// +/// This will poison the relevant query key if it is dropped without calling +/// [`Self::complete`]. +struct ActiveJobGuard<'tcx, K> where K: Eq + Hash + Copy, { state: &'tcx QueryState<'tcx, K>, key: K, + key_hash: u64, } #[cold] @@ -139,20 +143,19 @@ where } } -impl<'tcx, K> JobOwner<'tcx, K> +impl<'tcx, K> ActiveJobGuard<'tcx, K> where K: Eq + Hash + Copy, { /// Completes the query by updating the query cache with the `result`, - /// signals the waiter and forgets the JobOwner, so it won't poison the query - fn complete(self, cache: &C, key_hash: u64, result: C::Value, dep_node_index: DepNodeIndex) + /// signals the waiter, and forgets the guard so it won't poison the query. + fn complete(self, cache: &C, result: C::Value, dep_node_index: DepNodeIndex) where C: QueryCache, { - let key = self.key; - let state = self.state; - - // Forget ourself so our destructor won't poison the query + // Forget ourself so our destructor won't poison the query. + // (Extract fields by value first to make sure we don't leak anything.) + let Self { state, key, key_hash }: Self = self; mem::forget(self); // Mark as complete before we remove the job from the active state @@ -176,7 +179,7 @@ where } } -impl<'tcx, K> Drop for JobOwner<'tcx, K> +impl<'tcx, K> Drop for ActiveJobGuard<'tcx, K> where K: Eq + Hash + Copy, { @@ -184,11 +187,10 @@ where #[cold] fn drop(&mut self) { // Poison the query so jobs waiting on it panic. - let state = self.state; + let Self { state, key, key_hash } = *self; let job = { - let key_hash = sharded::make_hash(&self.key); let mut shard = state.active.lock_shard_by_hash(key_hash); - match shard.find_entry(key_hash, equivalent_key(&self.key)) { + match shard.find_entry(key_hash, equivalent_key(&key)) { Err(_) => panic!(), Ok(occupied) => { let ((key, value), vacant) = occupied.remove(); @@ -356,11 +358,13 @@ fn execute_job<'tcx, Q, const INCR: bool>( where Q: QueryDispatcher<'tcx, Qcx = QueryCtxt<'tcx>>, { - // Use `JobOwner` so the query will be poisoned if executing it panics. - let job_owner = JobOwner { state, key }; + // Set up a guard object that will automatically poison the query if a + // panic occurs while executing the query (or any intermediate plumbing). + let job_guard = ActiveJobGuard { state, key, key_hash }; debug_assert_eq!(qcx.tcx.dep_graph.is_fully_enabled(), INCR); + // Delegate to another function to actually execute the query job. let (result, dep_node_index) = if INCR { execute_job_incr(query, qcx, qcx.tcx.dep_graph.data().unwrap(), key, dep_node, id) } else { @@ -402,7 +406,9 @@ where } } } - job_owner.complete(cache, key_hash, result, dep_node_index); + + // Tell the guard to perform completion bookkeeping, and also to not poison the query. + job_guard.complete(cache, result, dep_node_index); (result, Some(dep_node_index)) }