Auto merge of #124703 - matthiaskrgr:rollup-2lljptd, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #123356 (Reduce code size of `thread::set_current`)
 - #124159 (Move thread parking to `sys::sync`)
 - #124293 (Let miri and const eval execute intrinsics' fallback bodies)
 - #124677 (Set non-leaf frame pointers on Fuchsia targets)
 - #124692 (We do not coerce `&mut &mut T -> *mut mut T`)
 - #124698 (Rewrite `rustdoc-determinism` test in Rust)
 - #124700 (Remove an unnecessary cast)
 - #124701 (Docs: suggest `uN::checked_sub` instead of check-then-unchecked)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 8 insertions, 3 deletions

diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs
index 604eb05040b..78bc9af6c4d 100644
--- a/library/std/src/thread/mod.rs
+++ b/library/std/src/thread/mod.rs
@@ -174,8 +174,8 @@ use crate::ptr::addr_of_mut;
 use crate::str;
 use crate::sync::atomic::{AtomicUsize, Ordering};
 use crate::sync::Arc;
+use crate::sys::sync::Parker;
 use crate::sys::thread as imp;
-use crate::sys_common::thread_parking::Parker;
 use crate::sys_common::{AsInner, IntoInner};
 use crate::time::{Duration, Instant};
 
@@ -703,9 +703,14 @@ thread_local! {
 
 /// Sets the thread handle for the current thread.
 ///
-/// Panics if the handle has been set already or when called from a TLS destructor.
+/// Aborts if the handle has been set already to reduce code size.
 pub(crate) fn set_current(thread: Thread) {
-    CURRENT.with(|current| current.set(thread).unwrap());
+    // Using `unwrap` here can add ~3kB to the binary size. We have complete
+    // control over where this is called, so just abort if there is a bug.
+    CURRENT.with(|current| match current.set(thread) {
+        Ok(()) => {}
+        Err(_) => rtabort!("thread::set_current should only be called once per thread"),
+    });
 }
 
 /// Gets a handle to the thread that invokes it.