core: Move locks, atomic rc to unstable::sync

11 files changed, 313 insertions, 295 deletions

diff --git a/src/libcore/comm.rs b/src/libcore/comm.rs
index b1f60ec4690..322584f8df1 100644
--- a/src/libcore/comm.rs
+++ b/src/libcore/comm.rs
@@ -19,8 +19,8 @@ use option::{Option, Some, None};
 use uint;
 use unstable;
 use vec;
-use unstable::Exclusive;
 use util::replace;
+use unstable::sync::{Exclusive, exclusive};
 
 use pipes::{recv, try_recv, wait_many, peek, PacketHeader};
 
@@ -304,7 +304,7 @@ pub struct SharedChan<T> {
 impl<T: Owned> SharedChan<T> {
     /// Converts a `chan` into a `shared_chan`.
     pub fn new(c: Chan<T>) -> SharedChan<T> {
-        SharedChan { ch: unstable::exclusive(c) }
+        SharedChan { ch: exclusive(c) }
     }
 }
 
diff --git a/src/libcore/os.rs b/src/libcore/os.rs
index 030b7ec3e42..1a8d996cc46 100644
--- a/src/libcore/os.rs
+++ b/src/libcore/os.rs
@@ -152,7 +152,7 @@ FIXME #4726: It would probably be appropriate to make this a real global
 */
 fn with_env_lock<T>(f: &fn() -> T) -> T {
     use unstable::global::global_data_clone_create;
-    use unstable::{Exclusive, exclusive};
+    use unstable::sync::{Exclusive, exclusive};
 
     struct SharedValue(());
     type ValueMutex = Exclusive<SharedValue>;
@@ -860,7 +860,7 @@ pub fn change_dir(p: &Path) -> bool {
 /// is otherwise unsuccessful.
 pub fn change_dir_locked(p: &Path, action: &fn()) -> bool {
     use unstable::global::global_data_clone_create;
-    use unstable::{Exclusive, exclusive};
+    use unstable::sync::{Exclusive, exclusive};
 
     fn key(_: Exclusive<()>) { }
 
diff --git a/src/libcore/task/spawn.rs b/src/libcore/task/spawn.rs
index 327b7a988aa..545f1ac8ada 100644
--- a/src/libcore/task/spawn.rs
+++ b/src/libcore/task/spawn.rs
@@ -90,6 +90,7 @@ use task::{ExistingScheduler, SchedulerHandle};
 use task::unkillable;
 use uint;
 use util;
+use unstable::sync::{Exclusive, exclusive};
 
 #[cfg(test)] use task::default_task_opts;
 
@@ -128,7 +129,7 @@ struct TaskGroupData {
     // tasks in this group.
     descendants: TaskSet,
 }
-type TaskGroupArc = unstable::Exclusive<Option<TaskGroupData>>;
+type TaskGroupArc = Exclusive<Option<TaskGroupData>>;
 
 type TaskGroupInner<'self> = &'self mut Option<TaskGroupData>;
 
@@ -158,7 +159,7 @@ struct AncestorNode {
     ancestors:      AncestorList,
 }
 
-struct AncestorList(Option<unstable::Exclusive<AncestorNode>>);
+struct AncestorList(Option<Exclusive<AncestorNode>>);
 
 // Accessors for taskgroup arcs and ancestor arcs that wrap the unsafety.
 #[inline(always)]
@@ -167,7 +168,7 @@ fn access_group<U>(x: &TaskGroupArc, blk: &fn(TaskGroupInner) -> U) -> U {
 }
 
 #[inline(always)]
-fn access_ancestors<U>(x: &unstable::Exclusive<AncestorNode>,
+fn access_ancestors<U>(x: &Exclusive<AncestorNode>,
                        blk: &fn(x: &mut AncestorNode) -> U) -> U {
     x.with(blk)
 }
@@ -479,7 +480,7 @@ fn gen_child_taskgroup(linked: bool, supervised: bool)
                     // here.
                     let mut members = new_taskset();
                     taskset_insert(&mut members, spawner);
-                    let tasks = unstable::exclusive(Some(TaskGroupData {
+                    let tasks = exclusive(Some(TaskGroupData {
                         members: members,
                         descendants: new_taskset(),
                     }));
@@ -508,7 +509,7 @@ fn gen_child_taskgroup(linked: bool, supervised: bool)
             (g, a, spawner_group.is_main)
         } else {
             // Child is in a separate group from spawner.
-            let g = unstable::exclusive(Some(TaskGroupData {
+            let g = exclusive(Some(TaskGroupData {
                 members:     new_taskset(),
                 descendants: new_taskset(),
             }));
@@ -528,7 +529,7 @@ fn gen_child_taskgroup(linked: bool, supervised: bool)
                     };
                 assert!(new_generation < uint::max_value);
                 // Build a new node in the ancestor list.
-                AncestorList(Some(unstable::exclusive(AncestorNode {
+                AncestorList(Some(exclusive(AncestorNode {
                     generation: new_generation,
                     parent_group: Some(spawner_group.tasks.clone()),
                     ancestors: old_ancestors,
diff --git a/src/libcore/unstable/global.rs b/src/libcore/unstable/global.rs
index eac686e28d1..27a003e0414 100644
--- a/src/libcore/unstable/global.rs
+++ b/src/libcore/unstable/global.rs
@@ -31,14 +31,14 @@ use kinds::Owned;
 use libc::{c_void};
 use option::{Option, Some, None};
 use ops::Drop;
-use unstable::{Exclusive, exclusive};
+use unstable::sync::{Exclusive, exclusive};
 use unstable::at_exit::at_exit;
 use unstable::intrinsics::atomic_cxchg;
 use hashmap::HashMap;
 use sys::Closure;
 
-#[cfg(test)] use unstable::{SharedMutableState, shared_mutable_state};
-#[cfg(test)] use unstable::get_shared_immutable_state;
+#[cfg(test)] use unstable::sync::{SharedMutableState, shared_mutable_state};
+#[cfg(test)] use unstable::sync::get_shared_immutable_state;
 #[cfg(test)] use task::spawn;
 #[cfg(test)] use uint;
 
diff --git a/src/libcore/unstable/mod.rs b/src/libcore/unstable/mod.rs
index ef7d70783c8..bef7a7f87d3 100644
--- a/src/libcore/unstable/mod.rs
+++ b/src/libcore/unstable/mod.rs
@@ -10,13 +10,10 @@
 
 #[doc(hidden)];
 
-use cast;
 use libc;
 use comm::{GenericChan, GenericPort};
 use prelude::*;
 use task;
-use task::atomically;
-use self::finally::Finally;
 
 pub mod at_exit;
 pub mod global;
@@ -28,23 +25,7 @@ pub mod simd;
 pub mod extfmt;
 #[cfg(not(test))]
 pub mod lang;
-
-mod rustrt {
-    use unstable::{raw_thread, rust_little_lock};
-
-    pub extern {
-        pub unsafe fn rust_create_little_lock() -> rust_little_lock;
-        pub unsafe fn rust_destroy_little_lock(lock: rust_little_lock);
-        pub unsafe fn rust_lock_little_lock(lock: rust_little_lock);
-        pub unsafe fn rust_unlock_little_lock(lock: rust_little_lock);
-
-        pub unsafe fn rust_raw_thread_start(f: &(&fn())) -> *raw_thread;
-        pub unsafe fn rust_raw_thread_join_delete(thread: *raw_thread);
-    }
-}
-
-#[allow(non_camel_case_types)] // runtime type
-pub type raw_thread = libc::c_void;
+pub mod sync;
 
 /**
 
@@ -63,8 +44,8 @@ pub fn run_in_bare_thread(f: ~fn()) {
             let closure: &fn() = || {
                 f()
             };
-            let thread = rustrt::rust_raw_thread_start(&closure);
-            rustrt::rust_raw_thread_join_delete(thread);
+            let thread = rust_raw_thread_start(&closure);
+            rust_raw_thread_join_delete(thread);
             chan.send(());
         }
     }
@@ -88,258 +69,10 @@ fn test_run_in_bare_thread_exchange() {
     }
 }
 
-fn compare_and_swap(address: &mut int, oldval: int, newval: int) -> bool {
-    unsafe {
-        let old = intrinsics::atomic_cxchg(address, oldval, newval);
-        old == oldval
-    }
-}
-
-/****************************************************************************
- * Shared state & exclusive ARC
- ****************************************************************************/
-
-struct ArcData<T> {
-    count:     libc::intptr_t,
-    // FIXME(#3224) should be able to make this non-option to save memory
-    data:      Option<T>,
-}
-
-struct ArcDestruct<T> {
-    data: *libc::c_void,
-}
-
-#[unsafe_destructor]
-impl<T> Drop for ArcDestruct<T>{
-    fn finalize(&self) {
-        unsafe {
-            do task::unkillable {
-                let mut data: ~ArcData<T> = cast::transmute(self.data);
-                let new_count =
-                    intrinsics::atomic_xsub(&mut data.count, 1) - 1;
-                assert!(new_count >= 0);
-                if new_count == 0 {
-                    // drop glue takes over.
-                } else {
-                    cast::forget(data);
-                }
-            }
-        }
-    }
-}
-
-fn ArcDestruct<T>(data: *libc::c_void) -> ArcDestruct<T> {
-    ArcDestruct {
-        data: data
-    }
-}
-
-/**
- * COMPLETELY UNSAFE. Used as a primitive for the safe versions in std::arc.
- *
- * Data races between tasks can result in crashes and, with sufficient
- * cleverness, arbitrary type coercion.
- */
-pub type SharedMutableState<T> = ArcDestruct<T>;
-
-pub unsafe fn shared_mutable_state<T:Owned>(data: T) ->
-        SharedMutableState<T> {
-    let data = ~ArcData { count: 1, data: Some(data) };
-    let ptr = cast::transmute(data);
-    ArcDestruct(ptr)
-}
-
-#[inline(always)]
-pub unsafe fn get_shared_mutable_state<T:Owned>(
-    rc: *SharedMutableState<T>) -> *mut T
-{
-    let ptr: ~ArcData<T> = cast::transmute((*rc).data);
-    assert!(ptr.count > 0);
-    let r = cast::transmute(ptr.data.get_ref());
-    cast::forget(ptr);
-    return r;
-}
-#[inline(always)]
-pub unsafe fn get_shared_immutable_state<'a,T:Owned>(
-        rc: &'a SharedMutableState<T>) -> &'a T {
-    let ptr: ~ArcData<T> = cast::transmute((*rc).data);
-    assert!(ptr.count > 0);
-    // Cast us back into the correct region
-    let r = cast::transmute_region(ptr.data.get_ref());
-    cast::forget(ptr);
-    return r;
-}
-
-pub unsafe fn clone_shared_mutable_state<T:Owned>(rc: &SharedMutableState<T>)
-        -> SharedMutableState<T> {
-    let mut ptr: ~ArcData<T> = cast::transmute((*rc).data);
-    let new_count = intrinsics::atomic_xadd(&mut ptr.count, 1) + 1;
-    assert!(new_count >= 2);
-    cast::forget(ptr);
-    ArcDestruct((*rc).data)
-}
-
-impl<T:Owned> Clone for SharedMutableState<T> {
-    fn clone(&self) -> SharedMutableState<T> {
-        unsafe {
-            clone_shared_mutable_state(self)
-        }
-    }
-}
-
-/****************************************************************************/
-
 #[allow(non_camel_case_types)] // runtime type
-pub type rust_little_lock = *libc::c_void;
-
-struct LittleLock {
-    l: rust_little_lock,
-}
-
-impl Drop for LittleLock {
-    fn finalize(&self) {
-        unsafe {
-            rustrt::rust_destroy_little_lock(self.l);
-        }
-    }
-}
-
-fn LittleLock() -> LittleLock {
-    unsafe {
-        LittleLock {
-            l: rustrt::rust_create_little_lock()
-        }
-    }
-}
-
-pub impl LittleLock {
-    #[inline(always)]
-    unsafe fn lock<T>(&self, f: &fn() -> T) -> T {
-        do atomically {
-            rustrt::rust_lock_little_lock(self.l);
-            do (|| {
-                f()
-            }).finally {
-                rustrt::rust_unlock_little_lock(self.l);
-            }
-        }
-    }
-}
-
-struct ExData<T> {
-    lock: LittleLock,
-    failed: bool,
-    data: T,
-}
-
-/**
- * An arc over mutable data that is protected by a lock. For library use only.
- */
-pub struct Exclusive<T> {
-    x: SharedMutableState<ExData<T>>
-}
-
-pub fn exclusive<T:Owned>(user_data: T) -> Exclusive<T> {
-    let data = ExData {
-        lock: LittleLock(),
-        failed: false,
-        data: user_data
-    };
-    Exclusive {
-        x: unsafe {
-            shared_mutable_state(data)
-        }
-    }
-}
-
-impl<T:Owned> Clone for Exclusive<T> {
-    // Duplicate an exclusive ARC, as std::arc::clone.
-    fn clone(&self) -> Exclusive<T> {
-        Exclusive { x: unsafe { clone_shared_mutable_state(&self.x) } }
-    }
-}
-
-pub impl<T:Owned> Exclusive<T> {
-    // Exactly like std::arc::mutex_arc,access(), but with the little_lock
-    // instead of a proper mutex. Same reason for being unsafe.
-    //
-    // Currently, scheduling operations (i.e., yielding, receiving on a pipe,
-    // accessing the provided condition variable) are prohibited while inside
-    // the exclusive. Supporting that is a work in progress.
-    #[inline(always)]
-    unsafe fn with<U>(&self, f: &fn(x: &mut T) -> U) -> U {
-        let rec = get_shared_mutable_state(&self.x);
-        do (*rec).lock.lock {
-            if (*rec).failed {
-                fail!(
-                    ~"Poisoned exclusive - another task failed inside!");
-            }
-            (*rec).failed = true;
-            let result = f(&mut (*rec).data);
-            (*rec).failed = false;
-            result
-        }
-    }
-
-    #[inline(always)]
-    unsafe fn with_imm<U>(&self, f: &fn(x: &T) -> U) -> U {
-        do self.with |x| {
-            f(cast::transmute_immut(x))
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use comm;
-    use super::exclusive;
-    use task;
-    use uint;
-
-    #[test]
-    fn exclusive_arc() {
-        let mut futures = ~[];
-
-        let num_tasks = 10;
-        let count = 10;
-
-        let total = exclusive(~0);
-
-        for uint::range(0, num_tasks) |_i| {
-            let total = total.clone();
-            let (port, chan) = comm::stream();
-            futures.push(port);
-
-            do task::spawn || {
-                for uint::range(0, count) |_i| {
-                    do total.with |count| {
-                        **count += 1;
-                    }
-                }
-                chan.send(());
-            }
-        };
-
-        for futures.each |f| { f.recv() }
-
-        do total.with |total| {
-            assert!(**total == num_tasks * count)
-        };
-    }
+pub type raw_thread = libc::c_void;
 
-    #[test] #[should_fail] #[ignore(cfg(windows))]
-    fn exclusive_poison() {
-        // Tests that if one task fails inside of an exclusive, subsequent
-        // accesses will also fail.
-        let x = exclusive(1);
-        let x2 = x.clone();
-        do task::try || {
-            do x2.with |one| {
-                assert!(*one == 2);
-            }
-        };
-        do x.with |one| {
-            assert!(*one == 1);
-        }
-    }
+extern {
+    fn rust_raw_thread_start(f: &(&fn())) -> *raw_thread;
+    fn rust_raw_thread_join_delete(thread: *raw_thread);
 }
diff --git a/src/libcore/unstable/sync.rs b/src/libcore/unstable/sync.rs
new file mode 100644
index 00000000000..691f893c4fc
--- /dev/null
+++ b/src/libcore/unstable/sync.rs
@@ -0,0 +1,283 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cast;
+use libc;
+use option::*;
+use task;
+use task::atomically;
+use unstable::finally::Finally;
+use unstable::intrinsics;
+use ops::Drop;
+use clone::Clone;
+use kinds::Owned;
+
+/****************************************************************************
+ * Shared state & exclusive ARC
+ ****************************************************************************/
+
+struct ArcData<T> {
+    count:     libc::intptr_t,
+    // FIXME(#3224) should be able to make this non-option to save memory
+    data:      Option<T>,
+}
+
+struct ArcDestruct<T> {
+    data: *libc::c_void,
+}
+
+#[unsafe_destructor]
+impl<T> Drop for ArcDestruct<T>{
+    fn finalize(&self) {
+        unsafe {
+            do task::unkillable {
+                let mut data: ~ArcData<T> = cast::transmute(self.data);
+                let new_count =
+                    intrinsics::atomic_xsub(&mut data.count, 1) - 1;
+                assert!(new_count >= 0);
+                if new_count == 0 {
+                    // drop glue takes over.
+                } else {
+                    cast::forget(data);
+                }
+            }
+        }
+    }
+}
+
+fn ArcDestruct<T>(data: *libc::c_void) -> ArcDestruct<T> {
+    ArcDestruct {
+        data: data
+    }
+}
+
+/**
+ * COMPLETELY UNSAFE. Used as a primitive for the safe versions in std::arc.
+ *
+ * Data races between tasks can result in crashes and, with sufficient
+ * cleverness, arbitrary type coercion.
+ */
+pub type SharedMutableState<T> = ArcDestruct<T>;
+
+pub unsafe fn shared_mutable_state<T:Owned>(data: T) ->
+        SharedMutableState<T> {
+    let data = ~ArcData { count: 1, data: Some(data) };
+    let ptr = cast::transmute(data);
+    ArcDestruct(ptr)
+}
+
+#[inline(always)]
+pub unsafe fn get_shared_mutable_state<T:Owned>(
+    rc: *SharedMutableState<T>) -> *mut T
+{
+    let ptr: ~ArcData<T> = cast::transmute((*rc).data);
+    assert!(ptr.count > 0);
+    let r = cast::transmute(ptr.data.get_ref());
+    cast::forget(ptr);
+    return r;
+}
+#[inline(always)]
+pub unsafe fn get_shared_immutable_state<'a,T:Owned>(
+        rc: &'a SharedMutableState<T>) -> &'a T {
+    let ptr: ~ArcData<T> = cast::transmute((*rc).data);
+    assert!(ptr.count > 0);
+    // Cast us back into the correct region
+    let r = cast::transmute_region(ptr.data.get_ref());
+    cast::forget(ptr);
+    return r;
+}
+
+pub unsafe fn clone_shared_mutable_state<T:Owned>(rc: &SharedMutableState<T>)
+        -> SharedMutableState<T> {
+    let mut ptr: ~ArcData<T> = cast::transmute((*rc).data);
+    let new_count = intrinsics::atomic_xadd(&mut ptr.count, 1) + 1;
+    assert!(new_count >= 2);
+    cast::forget(ptr);
+    ArcDestruct((*rc).data)
+}
+
+impl<T:Owned> Clone for SharedMutableState<T> {
+    fn clone(&self) -> SharedMutableState<T> {
+        unsafe {
+            clone_shared_mutable_state(self)
+        }
+    }
+}
+
+/****************************************************************************/
+
+#[allow(non_camel_case_types)] // runtime type
+pub type rust_little_lock = *libc::c_void;
+
+struct LittleLock {
+    l: rust_little_lock,
+}
+
+impl Drop for LittleLock {
+    fn finalize(&self) {
+        unsafe {
+            rust_destroy_little_lock(self.l);
+        }
+    }
+}
+
+fn LittleLock() -> LittleLock {
+    unsafe {
+        LittleLock {
+            l: rust_create_little_lock()
+        }
+    }
+}
+
+pub impl LittleLock {
+    #[inline(always)]
+    unsafe fn lock<T>(&self, f: &fn() -> T) -> T {
+        do atomically {
+            rust_lock_little_lock(self.l);
+            do (|| {
+                f()
+            }).finally {
+                rust_unlock_little_lock(self.l);
+            }
+        }
+    }
+}
+
+struct ExData<T> {
+    lock: LittleLock,
+    failed: bool,
+    data: T,
+}
+
+/**
+ * An arc over mutable data that is protected by a lock. For library use only.
+ */
+pub struct Exclusive<T> {
+    x: SharedMutableState<ExData<T>>
+}
+
+pub fn exclusive<T:Owned>(user_data: T) -> Exclusive<T> {
+    let data = ExData {
+        lock: LittleLock(),
+        failed: false,
+        data: user_data
+    };
+    Exclusive {
+        x: unsafe {
+            shared_mutable_state(data)
+        }
+    }
+}
+
+impl<T:Owned> Clone for Exclusive<T> {
+    // Duplicate an exclusive ARC, as std::arc::clone.
+    fn clone(&self) -> Exclusive<T> {
+        Exclusive { x: unsafe { clone_shared_mutable_state(&self.x) } }
+    }
+}
+
+pub impl<T:Owned> Exclusive<T> {
+    // Exactly like std::arc::mutex_arc,access(), but with the little_lock
+    // instead of a proper mutex. Same reason for being unsafe.
+    //
+    // Currently, scheduling operations (i.e., yielding, receiving on a pipe,
+    // accessing the provided condition variable) are prohibited while inside
+    // the exclusive. Supporting that is a work in progress.
+    #[inline(always)]
+    unsafe fn with<U>(&self, f: &fn(x: &mut T) -> U) -> U {
+        let rec = get_shared_mutable_state(&self.x);
+        do (*rec).lock.lock {
+            if (*rec).failed {
+                fail!(
+                    ~"Poisoned exclusive - another task failed inside!");
+            }
+            (*rec).failed = true;
+            let result = f(&mut (*rec).data);
+            (*rec).failed = false;
+            result
+        }
+    }
+
+    #[inline(always)]
+    unsafe fn with_imm<U>(&self, f: &fn(x: &T) -> U) -> U {
+        do self.with |x| {
+            f(cast::transmute_immut(x))
+        }
+    }
+}
+
+fn compare_and_swap(address: &mut int, oldval: int, newval: int) -> bool {
+    unsafe {
+        let old = intrinsics::atomic_cxchg(address, oldval, newval);
+        old == oldval
+    }
+}
+
+extern {
+    fn rust_create_little_lock() -> rust_little_lock;
+    fn rust_destroy_little_lock(lock: rust_little_lock);
+    fn rust_lock_little_lock(lock: rust_little_lock);
+    fn rust_unlock_little_lock(lock: rust_little_lock);
+}
+
+#[cfg(test)]
+mod tests {
+    use comm;
+    use super::exclusive;
+    use task;
+    use uint;
+
+    #[test]
+    fn exclusive_arc() {
+        let mut futures = ~[];
+
+        let num_tasks = 10;
+        let count = 10;
+
+        let total = exclusive(~0);
+
+        for uint::range(0, num_tasks) |_i| {
+            let total = total.clone();
+            let (port, chan) = comm::stream();
+            futures.push(port);
+
+            do task::spawn || {
+                for uint::range(0, count) |_i| {
+                    do total.with |count| {
+                        **count += 1;
+                    }
+                }
+                chan.send(());
+            }
+        };
+
+        for futures.each |f| { f.recv() }
+
+        do total.with |total| {
+            assert!(**total == num_tasks * count)
+        };
+    }
+
+    #[test] #[should_fail] #[ignore(cfg(windows))]
+    fn exclusive_poison() {
+        // Tests that if one task fails inside of an exclusive, subsequent
+        // accesses will also fail.
+        let x = exclusive(1);
+        let x2 = x.clone();
+        do task::try || {
+            do x2.with |one| {
+                assert!(*one == 2);
+            }
+        };
+        do x.with |one| {
+            assert!(*one == 1);
+        }
+    }
+}
diff --git a/src/libcore/vec.rs b/src/libcore/vec.rs
index 604f0297b64..e56144ebc0a 100644
--- a/src/libcore/vec.rs
+++ b/src/libcore/vec.rs
@@ -3298,8 +3298,9 @@ mod tests {
     #[test]
     fn test_swap_remove_noncopyable() {
         // Tests that we don't accidentally run destructors twice.
-        let mut v = ~[::unstable::exclusive(()), ::unstable::exclusive(()),
-                      ::unstable::exclusive(())];
+        let mut v = ~[::unstable::sync::exclusive(()),
+                      ::unstable::sync::exclusive(()),
+                      ::unstable::sync::exclusive(())];
         let mut _e = v.swap_remove(0);
         assert!(v.len() == 2);
         _e = v.swap_remove(1);
diff --git a/src/libstd/arc.rs b/src/libstd/arc.rs
index 7af68f3321d..86a77f36fb6 100644
--- a/src/libstd/arc.rs
+++ b/src/libstd/arc.rs
@@ -17,9 +17,9 @@ use sync;
 use sync::{Mutex, mutex_with_condvars, RWlock, rwlock_with_condvars};
 
 use core::cast;
-use core::unstable::{SharedMutableState, shared_mutable_state};
-use core::unstable::{clone_shared_mutable_state};
-use core::unstable::{get_shared_mutable_state, get_shared_immutable_state};
+use core::unstable::sync::{SharedMutableState, shared_mutable_state};
+use core::unstable::sync::{clone_shared_mutable_state};
+use core::unstable::sync::{get_shared_mutable_state, get_shared_immutable_state};
 use core::ptr;
 use core::task;
 
diff --git a/src/libstd/sync.rs b/src/libstd/sync.rs
index 17d051518a9..108f24d60dc 100644
--- a/src/libstd/sync.rs
+++ b/src/libstd/sync.rs
@@ -15,7 +15,7 @@
  * in std.
  */
 
-use core::unstable::{Exclusive, exclusive};
+use core::unstable::sync::{Exclusive, exclusive};
 use core::ptr;
 use core::task;
 use core::util;
diff --git a/src/test/compile-fail/noncopyable-match-pattern.rs b/src/test/compile-fail/noncopyable-match-pattern.rs
index e8b01765a44..155b3981483 100644
--- a/src/test/compile-fail/noncopyable-match-pattern.rs
+++ b/src/test/compile-fail/noncopyable-match-pattern.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 fn main() {
-    let x = Some(unstable::exclusive(false));
+    let x = Some(unstable::sync::exclusive(false));
     match x {
         Some(copy z) => { //~ ERROR copying a value of non-copyable type
             do z.with |b| { assert!(!*b); }
diff --git a/src/test/run-pass/alt-ref-binding-in-guard-3256.rs b/src/test/run-pass/alt-ref-binding-in-guard-3256.rs
index 1ece3b5fd93..ed7a6316374 100644
--- a/src/test/run-pass/alt-ref-binding-in-guard-3256.rs
+++ b/src/test/run-pass/alt-ref-binding-in-guard-3256.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 pub fn main() {
-    let x = Some(unstable::exclusive(true));
+    let x = Some(unstable::sync::exclusive(true));
     match x {
         Some(ref z) if z.with(|b| *b) => {
             do z.with |b| { assert!(*b); }