Auto merge of #107586 - SparrowLii:parallel-query, r=cjgillot

Introduce `DynSend` and `DynSync` auto trait for parallel compiler

part of parallel-rustc #101566

This PR introduces `DynSend / DynSync` trait and `FromDyn / IntoDyn` structure in rustc_data_structure::marker. `FromDyn` can dynamically check data structures for thread safety when switching to parallel environments (such as calling `par_for_each_in`). This happens only when `-Z threads > 1` so it doesn't affect single-threaded mode's compile efficiency.

r? `@cjgillot`

2 files changed, 10 insertions, 6 deletions

diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index fcbd9a53b48..22c41f7b93f 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -32,7 +32,7 @@ use emitter::{is_case_difference, Emitter, EmitterWriter};
 use registry::Registry;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::stable_hasher::{Hash128, StableHasher};
-use rustc_data_structures::sync::{self, Lock, Lrc};
+use rustc_data_structures::sync::{self, IntoDynSyncSend, Lock, Lrc};
 use rustc_data_structures::AtomicRef;
 pub use rustc_error_messages::{
     fallback_fluent_bundle, fluent_bundle, DelayDm, DiagnosticMessage, FluentBundle,
@@ -409,7 +409,7 @@ struct HandlerInner {
     err_count: usize,
     warn_count: usize,
     deduplicated_err_count: usize,
-    emitter: Box<dyn Emitter + sync::Send>,
+    emitter: IntoDynSyncSend<Box<dyn Emitter + sync::Send>>,
     delayed_span_bugs: Vec<DelayedDiagnostic>,
     delayed_good_path_bugs: Vec<DelayedDiagnostic>,
     /// This flag indicates that an expected diagnostic was emitted and suppressed.
@@ -605,7 +605,7 @@ impl Handler {
                 warn_count: 0,
                 deduplicated_err_count: 0,
                 deduplicated_warn_count: 0,
-                emitter,
+                emitter: IntoDynSyncSend(emitter),
                 delayed_span_bugs: Vec::new(),
                 delayed_good_path_bugs: Vec::new(),
                 suppressed_expected_diag: false,
diff --git a/compiler/rustc_errors/src/tests.rs b/compiler/rustc_errors/src/tests.rs
index 52103e46097..0e729b71680 100644
--- a/compiler/rustc_errors/src/tests.rs
+++ b/compiler/rustc_errors/src/tests.rs
@@ -2,7 +2,7 @@ use crate::error::{TranslateError, TranslateErrorKind};
 use crate::fluent_bundle::*;
 use crate::translation::Translate;
 use crate::FluentBundle;
-use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::sync::{IntoDynSyncSend, Lrc};
 use rustc_error_messages::fluent_bundle::resolver::errors::{ReferenceKind, ResolverError};
 use rustc_error_messages::langid;
 use rustc_error_messages::DiagnosticMessage;
@@ -27,10 +27,14 @@ fn make_dummy(ftl: &'static str) -> Dummy {
     let langid_en = langid!("en-US");
 
     #[cfg(parallel_compiler)]
-    let mut bundle = FluentBundle::new_concurrent(vec![langid_en]);
+    let mut bundle: FluentBundle =
+        IntoDynSyncSend(crate::fluent_bundle::bundle::FluentBundle::new_concurrent(vec![
+            langid_en,
+        ]));
 
     #[cfg(not(parallel_compiler))]
-    let mut bundle = FluentBundle::new(vec![langid_en]);
+    let mut bundle: FluentBundle =
+        IntoDynSyncSend(crate::fluent_bundle::bundle::FluentBundle::new(vec![langid_en]));
 
     bundle.add_resource(resource).expect("Failed to add FTL resources to the bundle.");