correct literals for dyn thread safe

11 files changed, 48 insertions, 41 deletions

diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 3b47ebef2fd..3f0b1627afa 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -48,7 +48,7 @@ pub enum TokenTree {
     Delimited(DelimSpan, Delimiter, TokenStream),
 }
 
-// Ensure all fields of `TokenTree` is `DynSend` and `DynSync`.
+// Ensure all fields of `TokenTree` are `DynSend` and `DynSync`.
 #[cfg(parallel_compiler)]
 fn _dummy()
 where
diff --git a/compiler/rustc_data_structures/src/marker.rs b/compiler/rustc_data_structures/src/marker.rs
index 62e65209d72..6dad2bac58a 100644
--- a/compiler/rustc_data_structures/src/marker.rs
+++ b/compiler/rustc_data_structures/src/marker.rs
@@ -8,20 +8,20 @@ cfg_if!(
     } else {
         #[rustc_on_unimplemented(
             message = "`{Self}` doesn't implement `DynSend`. \
-            Add it to `rustc_data_structures::marker` or use `IntoDyn` if it's already `Send`"
+            Add it to `rustc_data_structures::marker` or use `IntoDynSyncSend` if it's already `Send`"
         )]
         // This is an auto trait for types which can be sent across threads if `sync::is_dyn_thread_safe()`
         // is true. These types can be wrapped in a `FromDyn` to get a `Send` type. Wrapping a
-        // `Send` type in `IntoDyn` will create a `DynSend` type.
+        // `Send` type in `IntoDynSyncSend` will create a `DynSend` type.
         pub unsafe auto trait DynSend {}
 
         #[rustc_on_unimplemented(
             message = "`{Self}` doesn't implement `DynSync`. \
-            Add it to `rustc_data_structures::marker` or use `IntoDyn` if it's already `Sync`"
+            Add it to `rustc_data_structures::marker` or use `IntoDynSyncSend` if it's already `Sync`"
         )]
         // This is an auto trait for types which can be shared across threads if `sync::is_dyn_thread_safe()`
         // is true. These types can be wrapped in a `FromDyn` to get a `Sync` type. Wrapping a
-        // `Sync` type in `IntoDyn` will create a `DynSync` type.
+        // `Sync` type in `IntoDynSyncSend` will create a `DynSync` type.
         pub unsafe auto trait DynSync {}
 
         // Same with `Sync` and `Send`.
@@ -234,15 +234,18 @@ impl<T> const std::ops::Deref for FromDyn<T> {
     }
 }
 
+// A wrapper to convert a struct that is already a `Send` or `Sync` into
+// an instance of `DynSend` and `DynSync`, since the compiler cannot infer
+// it automatically in some cases. (e.g. Box<dyn Send / Sync>)
 #[derive(Copy, Clone)]
-pub struct IntoDyn<T: ?Sized>(pub T);
+pub struct IntoDynSyncSend<T: ?Sized>(pub T);
 
 #[cfg(parallel_compiler)]
-unsafe impl<T: ?Sized + Send> DynSend for IntoDyn<T> {}
+unsafe impl<T: ?Sized + Send> DynSend for IntoDynSyncSend<T> {}
 #[cfg(parallel_compiler)]
-unsafe impl<T: ?Sized + Sync> DynSync for IntoDyn<T> {}
+unsafe impl<T: ?Sized + Sync> DynSync for IntoDynSyncSend<T> {}
 
-impl<T> const std::ops::Deref for IntoDyn<T> {
+impl<T> const std::ops::Deref for IntoDynSyncSend<T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -250,7 +253,7 @@ impl<T> const std::ops::Deref for IntoDyn<T> {
     }
 }
 
-impl<T> const std::ops::DerefMut for IntoDyn<T> {
+impl<T> const std::ops::DerefMut for IntoDynSyncSend<T> {
     fn deref_mut(&mut self) -> &mut T {
         &mut self.0
     }
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 41aad2ff4e4..8a778866a77 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -61,25 +61,25 @@ mod mode {
     use std::sync::atomic::AtomicU8;
 
     const UNINITIALIZED: u8 = 0;
-    const DYN_NOT_SYNC: u8 = 1;
-    const DYN_SYNC: u8 = 2;
+    const DYN_NOT_THREAD_SAFE: u8 = 1;
+    const DYN_THREAD_SAFE: u8 = 2;
 
-    static DYN_SYNC_MODE: AtomicU8 = AtomicU8::new(UNINITIALIZED);
+    static DYN_THREAD_SAFE_MODE: AtomicU8 = AtomicU8::new(UNINITIALIZED);
 
-    // Weather control thread safety dynamically
+    // Whether thread safety is enabled (due to running under multiple threads).
     #[inline]
     pub fn is_dyn_thread_safe() -> bool {
-        match DYN_SYNC_MODE.load(Ordering::Relaxed) {
-            DYN_NOT_SYNC => false,
-            DYN_SYNC => true,
-            _ => panic!("uninitialized parallel mode!"),
+        match DYN_THREAD_SAFE_MODE.load(Ordering::Relaxed) {
+            DYN_NOT_THREAD_SAFE => false,
+            DYN_THREAD_SAFE => true,
+            _ => panic!("uninitialized dyn_thread_safe mode!"),
         }
     }
 
     // Only set by the `-Z threads` compile option
-    pub fn set_dyn_thread_safe_mode(parallel: bool) {
-        let set: u8 = if parallel { DYN_SYNC } else { DYN_NOT_SYNC };
-        let previous = DYN_SYNC_MODE.compare_exchange(
+    pub fn set_dyn_thread_safe_mode(mode: bool) {
+        let set: u8 = if mode { DYN_THREAD_SAFE } else { DYN_NOT_THREAD_SAFE };
+        let previous = DYN_THREAD_SAFE_MODE.compare_exchange(
             UNINITIALIZED,
             set,
             Ordering::Relaxed,
@@ -401,7 +401,7 @@ cfg_if! {
                 if rustc_data_structures::sync::is_dyn_thread_safe() {
                     // Reverse the order of the later blocks since Rayon executes them in reverse order
                     // when using a single thread. This ensures the execution order matches that
-                    // of a single threaded rustc
+                    // of a single threaded rustc.
                     parallel!(impl $fblock [] [$($blocks),*]);
                 } else {
                     // We catch panics here ensuring that all the blocks execute.
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 353f49e6619..b94fb335a4e 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -255,8 +255,8 @@ fn run_compiler(
 
     let sopts = config::build_session_options(&matches);
 
-    // Set parallel mode before thread pool creation as the session will already create locks.
-    interface::set_parallel_mode(&sopts.unstable_opts);
+    // Set parallel mode before thread pool creation, which will create `Lock`s.
+    interface::set_thread_safe_mode(&sopts.unstable_opts);
 
     if let Some(ref code) = matches.opt_str("explain") {
         handle_explain(diagnostics_registry(), code, sopts.error_format);
diff --git a/compiler/rustc_error_messages/src/lib.rs b/compiler/rustc_error_messages/src/lib.rs
index 2b7c8dc5f3d..0accb4ab96f 100644
--- a/compiler/rustc_error_messages/src/lib.rs
+++ b/compiler/rustc_error_messages/src/lib.rs
@@ -11,7 +11,7 @@ extern crate tracing;
 use fluent_bundle::FluentResource;
 use fluent_syntax::parser::ParserError;
 use icu_provider_adapters::fallback::{LocaleFallbackProvider, LocaleFallbacker};
-use rustc_data_structures::sync::{IntoDyn, Lrc};
+use rustc_data_structures::sync::{IntoDynSyncSend, Lrc};
 use rustc_fluent_macro::fluent_messages;
 use rustc_macros::{Decodable, Encodable};
 use rustc_span::Span;
@@ -38,16 +38,16 @@ pub use unic_langid::{langid, LanguageIdentifier};
 fluent_messages! { "../messages.ftl" }
 
 pub type FluentBundle =
-    IntoDyn<fluent_bundle::bundle::FluentBundle<FluentResource, IntlLangMemoizer>>;
+    IntoDynSyncSend<fluent_bundle::bundle::FluentBundle<FluentResource, IntlLangMemoizer>>;
 
 #[cfg(not(parallel_compiler))]
 fn new_bundle(locales: Vec<LanguageIdentifier>) -> FluentBundle {
-    IntoDyn(fluent_bundle::bundle::FluentBundle::new(locales))
+    IntoDynSyncSend(fluent_bundle::bundle::FluentBundle::new(locales))
 }
 
 #[cfg(parallel_compiler)]
 fn new_bundle(locales: Vec<LanguageIdentifier>) -> FluentBundle {
-    IntoDyn(fluent_bundle::bundle::FluentBundle::new_concurrent(locales))
+    IntoDynSyncSend(fluent_bundle::bundle::FluentBundle::new_concurrent(locales))
 }
 
 #[derive(Debug)]
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index f57bb8d8bdc..64fbf22c262 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, IntoDyn, 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: IntoDyn<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: IntoDyn(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 08b3281d9a5..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::{IntoDyn, 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;
@@ -28,11 +28,13 @@ fn make_dummy(ftl: &'static str) -> Dummy {
 
     #[cfg(parallel_compiler)]
     let mut bundle: FluentBundle =
-        IntoDyn(crate::fluent_bundle::bundle::FluentBundle::new_concurrent(vec![langid_en]));
+        IntoDynSyncSend(crate::fluent_bundle::bundle::FluentBundle::new_concurrent(vec![
+            langid_en,
+        ]));
 
     #[cfg(not(parallel_compiler))]
     let mut bundle: FluentBundle =
-        IntoDyn(crate::fluent_bundle::bundle::FluentBundle::new(vec![langid_en]));
+        IntoDynSyncSend(crate::fluent_bundle::bundle::FluentBundle::new(vec![langid_en]));
 
     bundle.add_resource(resource).expect("Failed to add FTL resources to the bundle.");
 
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index fb6c273e929..ee373f72ee9 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -61,7 +61,7 @@ impl Compiler {
 }
 
 #[allow(rustc::bad_opt_access)]
-pub fn set_parallel_mode(sopts: &config::UnstableOptions) {
+pub fn set_thread_safe_mode(sopts: &config::UnstableOptions) {
     rustc_data_structures::sync::set_dyn_thread_safe_mode(sopts.threads > 1);
 }
 
diff --git a/compiler/rustc_middle/src/ty/list.rs b/compiler/rustc_middle/src/ty/list.rs
index 8f99a051328..71911a5a618 100644
--- a/compiler/rustc_middle/src/ty/list.rs
+++ b/compiler/rustc_middle/src/ty/list.rs
@@ -199,7 +199,7 @@ impl<'a, T: Copy> IntoIterator for &'a List<T> {
 
 unsafe impl<T: Sync> Sync for List<T> {}
 
-// We need this since `List` uses extern type `OpaqueListContents`
+// We need this since `List` uses extern type `OpaqueListContents`.
 #[cfg(parallel_compiler)]
 use rustc_data_structures::sync::DynSync;
 #[cfg(parallel_compiler)]
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index e0a2733a464..8238a16969d 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -14,7 +14,9 @@ pub use crate::*;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{Hash128, Hash64, StableHasher};
-use rustc_data_structures::sync::{AtomicU32, IntoDyn, Lrc, MappedReadGuard, ReadGuard, RwLock};
+use rustc_data_structures::sync::{
+    AtomicU32, IntoDynSyncSend, Lrc, MappedReadGuard, ReadGuard, RwLock,
+};
 use std::cmp;
 use std::hash::Hash;
 use std::path::{self, Path, PathBuf};
@@ -176,7 +178,7 @@ pub struct SourceMap {
     used_address_space: AtomicU32,
 
     files: RwLock<SourceMapFiles>,
-    file_loader: IntoDyn<Box<dyn FileLoader + Sync + Send>>,
+    file_loader: IntoDynSyncSend<Box<dyn FileLoader + Sync + Send>>,
     // This is used to apply the file path remapping as specified via
     // `--remap-path-prefix` to all `SourceFile`s allocated within this `SourceMap`.
     path_mapping: FilePathMapping,
@@ -202,7 +204,7 @@ impl SourceMap {
         SourceMap {
             used_address_space: AtomicU32::new(0),
             files: Default::default(),
-            file_loader: IntoDyn(file_loader),
+            file_loader: IntoDynSyncSend(file_loader),
             path_mapping,
             hash_kind,
         }
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index ba71d0372a7..70b6ba1aced 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -730,8 +730,8 @@ fn main_args(at_args: &[String]) -> MainResult {
         }
     };
 
-    // Set parallel mode early as the error handler will already create locks.
-    interface::set_parallel_mode(&options.unstable_opts);
+    // Set parallel mode before error handler creation, which will create `Lock`s.
+    interface::set_thread_safe_mode(&options.unstable_opts);
 
     let diag = core::new_handler(
         options.error_format,