From 8e7c4888b717a24dfc68f47c5dde00334fed2317 Mon Sep 17 00:00:00 2001
From: Alex Burka <alex@alexburka.com>
Date: Fri, 21 Apr 2017 04:30:08 +0000
Subject: [PATCH] stage0 fallback

---
 src/libstd/thread/local.rs | 67 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/src/libstd/thread/local.rs b/src/libstd/thread/local.rs
index c3aa3ff79c6..8b2064c9d61 100644
--- a/src/libstd/thread/local.rs
+++ b/src/libstd/thread/local.rs
@@ -110,6 +110,7 @@ impl<T: 'static> fmt::Debug for LocalKey<T> {
     }
 }
 
+#[cfg(not(stage0))]
 /// Declare a new thread local storage key of type [`std::thread::LocalKey`].
 ///
 /// # Syntax
@@ -151,6 +152,7 @@ macro_rules! thread_local {
     );
 }
 
+#[cfg(not(stage0))]
 #[doc(hidden)]
 #[unstable(feature = "thread_local_internals",
            reason = "should not be necessary",
@@ -183,6 +185,71 @@ macro_rules! __thread_local_inner {
     }
 }
 
+#[cfg(stage0)]
+/// Declare a new thread local storage key of type `std::thread::LocalKey`.
+#[macro_export]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow_internal_unstable]
+macro_rules! thread_local {
+    // rule 0: empty (base case for the recursion)
+    () => {};
+
+    // rule 1: process multiple declarations where the first one is private
+    ($(#[$attr:meta])* static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => (
+        thread_local!($(#[$attr])* static $name: $t = $init); // go to rule 2
+        thread_local!($($rest)*);
+    );
+
+    // rule 2: handle a single private declaration
+    ($(#[$attr:meta])* static $name:ident: $t:ty = $init:expr) => (
+        $(#[$attr])* static $name: $crate::thread::LocalKey<$t> =
+            __thread_local_inner!($t, $init);
+    );
+
+    // rule 3: handle multiple declarations where the first one is public
+    ($(#[$attr:meta])* pub static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => (
+        thread_local!($(#[$attr])* pub static $name: $t = $init); // go to rule 4
+        thread_local!($($rest)*);
+    );
+
+    // rule 4: handle a single public declaration
+    ($(#[$attr:meta])* pub static $name:ident: $t:ty = $init:expr) => (
+        $(#[$attr])* pub static $name: $crate::thread::LocalKey<$t> =
+            __thread_local_inner!($t, $init);
+    );
+}
+
+#[cfg(stage0)]
+#[doc(hidden)]
+#[unstable(feature = "thread_local_internals",
+           reason = "should not be necessary",
+           issue = "0")]
+#[macro_export]
+#[allow_internal_unstable]
+macro_rules! __thread_local_inner {
+    ($t:ty, $init:expr) => {{
+        fn __init() -> $t { $init }
+
+        fn __getit() -> $crate::option::Option<
+            &'static $crate::cell::UnsafeCell<
+                $crate::option::Option<$t>>>
+        {
+            #[thread_local]
+            #[cfg(target_thread_local)]
+            static __KEY: $crate::thread::__FastLocalKeyInner<$t> =
+                $crate::thread::__FastLocalKeyInner::new();
+
+            #[cfg(not(target_thread_local))]
+            static __KEY: $crate::thread::__OsLocalKeyInner<$t> =
+                $crate::thread::__OsLocalKeyInner::new();
+
+            __KEY.get()
+        }
+
+        $crate::thread::LocalKey::new(__getit, __init)
+    }}
+}
+
 /// Indicator of the state of a thread local storage key.
 #[unstable(feature = "thread_local_state",
            reason = "state querying was recently added",