From c6c4ea40dc645239ebcb0535be6b96a29983fd5b Mon Sep 17 00:00:00 2001
From: Askar Safin <safinaskar@mail.ru>
Date: Tue, 4 Mar 2025 15:32:55 +0300
Subject: [PATCH] Revert
"compiler/rustc_data_structures/src/sync/worker_local.rs: delete "unsafe impl
Sync""
This reverts commit 02406903b0c26440428580a4bbaf30da973c5b23.
---
.../rustc_data_structures/src/sync/worker_local.rs | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/compiler/rustc_data_structures/src/sync/worker_local.rs b/compiler/rustc_data_structures/src/sync/worker_local.rs
index 402ec9827bbaa..d75af00985047 100644
--- a/compiler/rustc_data_structures/src/sync/worker_local.rs
+++ b/compiler/rustc_data_structures/src/sync/worker_local.rs
@@ -106,6 +106,12 @@ pub struct WorkerLocal<T> {
registry: Registry,
}
+// This is safe because the `deref` call will return a reference to a `T` unique to each thread
+// or it will panic for threads without an associated local. So there isn't a need for `T` to do
+// it's own synchronization. The `verify` method on `RegistryId` has an issue where the id
+// can be reused, but `WorkerLocal` has a reference to `Registry` which will prevent any reuse.
+unsafe impl<T: Send> Sync for WorkerLocal<T> {}
+
impl<T> WorkerLocal<T> {
/// Creates a new worker local where the `initial` closure computes the
/// value this worker local should take for each thread in the registry.
@@ -132,11 +138,6 @@ impl<T> Deref for WorkerLocal<T> {
fn deref(&self) -> &T {
// This is safe because `verify` will only return values less than
// `self.registry.thread_limit` which is the size of the `self.locals` array.
-
- // The `deref` call will return a reference to a `T` unique to each thread
- // or it will panic for threads without an associated local. So there isn't a need for `T` to do
- // it's own synchronization. The `verify` method on `RegistryId` has an issue where the id
- // can be reused, but `WorkerLocal` has a reference to `Registry` which will prevent any reuse.
unsafe { &self.locals.get_unchecked(self.registry.id().verify()).0 }
}
}