1 files changed, 21 insertions, 17 deletions
diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs
index b9aaf5f6e15..f712c872708 100644
--- a/library/std/src/thread/mod.rs
+++ b/library/std/src/thread/mod.rs
@@ -131,7 +131,8 @@
 //!
 //! * Build the thread with [`Builder`] and pass the desired stack size to [`Builder::stack_size`].
 //! * Set the `RUST_MIN_STACK` environment variable to an integer representing the desired stack
-//!   size (in bytes). Note that setting [`Builder::stack_size`] will override this.
+//!   size (in bytes). Note that setting [`Builder::stack_size`] will override this. Be aware that
+//!   changes to `RUST_MIN_STACK` may be ignored after program start.
 //!
 //! Note that the stack size of the main thread is *not* determined by Rust.
 //!
@@ -192,20 +193,23 @@ pub use scoped::{scope, Scope, ScopedJoinHandle};
 #[macro_use]
 mod local;
 
-#[stable(feature = "rust1", since = "1.0.0")]
-pub use self::local::{AccessError, LocalKey};
-
-// Provide the type used by the thread_local! macro to access TLS keys. This
-// needs to be kept in sync with the macro itself (in `local.rs`).
-// There are three types: "static", "fast", "OS". The "OS" thread local key
-// type is accessed via platform-specific API calls and is slow, while the "fast"
-// key type is accessed via code generated via LLVM, where TLS keys are set up
-// by the elf linker. "static" is for single-threaded platforms where a global
-// static is sufficient.
-
-#[doc(hidden)]
-#[unstable(feature = "libstd_thread_internals", issue = "none")]
-pub use crate::sys::common::thread_local::Key as __LocalKeyInner;
+cfg_if::cfg_if! {
+    if #[cfg(test)] {
+        // Avoid duplicating the global state assoicated with thread-locals between this crate and
+        // realstd. Miri relies on this.
+        pub use realstd::thread::{local_impl, AccessError, LocalKey};
+    } else {
+        #[stable(feature = "rust1", since = "1.0.0")]
+        pub use self::local::{AccessError, LocalKey};
+
+        // Implementation details used by the thread_local!{} macro.
+        #[doc(hidden)]
+        #[unstable(feature = "thread_local_internals", issue = "none")]
+        pub mod local_impl {
+            pub use crate::sys::common::thread_local::{thread_local_inner, Key};
+        }
+    }
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 // Builder
@@ -493,7 +497,7 @@ impl Builder {
                 MaybeDangling(mem::MaybeUninit::new(x))
             }
             fn into_inner(self) -> T {
-                // SAFETY: we are always initiailized.
+                // SAFETY: we are always initialized.
                 let ret = unsafe { self.0.assume_init_read() };
                 // Make sure we don't drop.
                 mem::forget(self);
@@ -502,7 +506,7 @@ impl Builder {
         }
         impl<T> Drop for MaybeDangling<T> {
             fn drop(&mut self) {
-                // SAFETY: we are always initiailized.
+                // SAFETY: we are always initialized.
                 unsafe { self.0.assume_init_drop() };
             }
         }