std: Internalize almost all of `std::rt`

This commit does some refactoring to make almost all of the `std::rt` private.
Specifically, the following items are no longer part of its API:

* DEFAULT_ERROR_CODE
* backtrace
* unwind
* args
* at_exit
* cleanup
* heap (this is just alloc::heap)
* min_stack
* util

The module is now tagged as `#[doc(hidden)]` as the only purpose it's serve is
an entry point for the `panic!` macro via the `begin_unwind` and
`begin_unwind_fmt` reexports.

33 files changed, 272 insertions, 431 deletions

diff --git a/src/doc/nomicon/destructors.md b/src/doc/nomicon/destructors.md
index 29a866063e9..4492e2a92fa 100644
--- a/src/doc/nomicon/destructors.md
+++ b/src/doc/nomicon/destructors.md
@@ -26,13 +26,16 @@ this is totally fine.
 For instance, a custom implementation of `Box` might write `Drop` like this:
 
 ```rust
-#![feature(heap_api, core_intrinsics, unique)]
+#![feature(alloc, heap_api, core_intrinsics, unique)]
+
+extern crate alloc;
 
-use std::rt::heap;
 use std::ptr::Unique;
 use std::intrinsics::drop_in_place;
 use std::mem;
 
+use alloc::heap;
+
 struct Box<T>{ ptr: Unique<T> }
 
 impl<T> Drop for Box<T> {
@@ -45,6 +48,7 @@ impl<T> Drop for Box<T> {
         }
     }
 }
+# fn main() {}
 ```
 
 and this works fine because when Rust goes to drop the `ptr` field it just sees
@@ -54,13 +58,16 @@ use-after-free the `ptr` because when drop exits, it becomes inacessible.
 However this wouldn't work:
 
 ```rust
-#![feature(heap_api, core_intrinsics, unique)]
+#![feature(alloc, heap_api, core_intrinsics, unique)]
+
+extern crate alloc;
 
-use std::rt::heap;
 use std::ptr::Unique;
 use std::intrinsics::drop_in_place;
 use std::mem;
 
+use alloc::heap;
+
 struct Box<T>{ ptr: Unique<T> }
 
 impl<T> Drop for Box<T> {
@@ -87,6 +94,7 @@ impl<T> Drop for SuperBox<T> {
         }
     }
 }
+# fn main() {}
 ```
 
 After we deallocate the `box`'s ptr in SuperBox's destructor, Rust will
@@ -129,13 +137,16 @@ The classic safe solution to overriding recursive drop and allowing moving out
 of Self during `drop` is to use an Option:
 
 ```rust
-#![feature(heap_api, core_intrinsics, unique)]
+#![feature(alloc, heap_api, core_intrinsics, unique)]
+
+extern crate alloc;
 
-use std::rt::heap;
 use std::ptr::Unique;
 use std::intrinsics::drop_in_place;
 use std::mem;
 
+use alloc::heap;
+
 struct Box<T>{ ptr: Unique<T> }
 
 impl<T> Drop for Box<T> {
@@ -165,6 +176,7 @@ impl<T> Drop for SuperBox<T> {
         }
     }
 }
+# fn main() {}
 ```
 
 However this has fairly odd semantics: you're saying that a field that *should*
diff --git a/src/doc/nomicon/vec-alloc.md b/src/doc/nomicon/vec-alloc.md
index fc7feba2356..c2ae1a4eb6d 100644
--- a/src/doc/nomicon/vec-alloc.md
+++ b/src/doc/nomicon/vec-alloc.md
@@ -9,7 +9,7 @@ This is perfectly fine because we already have `cap == 0` as our sentinel for no
 allocation. We don't even need to handle it specially in almost any code because
 we usually need to check if `cap > len` or `len > 0` anyway. The traditional
 Rust value to put here is `0x01`. The standard library actually exposes this
-as `std::rt::heap::EMPTY`. There are quite a few places where we'll
+as `alloc::heap::EMPTY`. There are quite a few places where we'll
 want to use `heap::EMPTY` because there's no real allocation to talk about but
 `null` would make the compiler do bad things.
 
@@ -20,11 +20,12 @@ the `heap` API anyway, so let's just get that dependency over with.
 So:
 
 ```rust,ignore
-#![feature(heap_api)]
+#![feature(alloc, heap_api)]
 
-use std::rt::heap::EMPTY;
 use std::mem;
 
+use alloc::heap::EMPTY;
+
 impl<T> Vec<T> {
     fn new() -> Self {
         assert!(mem::size_of::<T>() != 0, "We're not ready to handle ZSTs");
diff --git a/src/doc/nomicon/vec-final.md b/src/doc/nomicon/vec-final.md
index ba4537f1640..52c22f65076 100644
--- a/src/doc/nomicon/vec-final.md
+++ b/src/doc/nomicon/vec-final.md
@@ -2,17 +2,16 @@
 
 ```rust
 #![feature(unique)]
-#![feature(heap_api)]
+#![feature(alloc, heap_api)]
+
+extern crate alloc;
 
 use std::ptr::{Unique, self};
-use std::rt::heap;
 use std::mem;
 use std::ops::{Deref, DerefMut};
 use std::marker::PhantomData;
 
-
-
-
+use alloc::heap;
 
 struct RawVec<T> {
     ptr: Unique<T>,
diff --git a/src/libarena/lib.rs b/src/libarena/lib.rs
index f48443e52b3..57e82720e8b 100644
--- a/src/libarena/lib.rs
+++ b/src/libarena/lib.rs
@@ -49,7 +49,8 @@ use std::marker;
 use std::mem;
 use std::ptr;
 use std::rc::Rc;
-use std::rt::heap::{allocate, deallocate};
+
+use alloc::heap::{allocate, deallocate};
 
 // The way arena uses arrays is really deeply awful. The arrays are
 // allocated, and have capacities reserved, but the fill for the array
diff --git a/src/liblog/lib.rs b/src/liblog/lib.rs
index 4517c2f9157..d59e40fb149 100644
--- a/src/liblog/lib.rs
+++ b/src/liblog/lib.rs
@@ -174,7 +174,6 @@
 #![feature(box_syntax)]
 #![feature(const_fn)]
 #![feature(iter_cmp)]
-#![feature(rt)]
 #![feature(staged_api)]
 #![feature(static_mutex)]
 
@@ -185,7 +184,6 @@ use std::io::prelude::*;
 use std::mem;
 use std::env;
 use std::ptr;
-use std::rt;
 use std::slice;
 use std::sync::{Once, StaticMutex};
 
@@ -292,7 +290,6 @@ pub fn log(level: u32, loc: &'static LogLocation, args: fmt::Arguments) {
         let _g = LOCK.lock();
         match FILTER as usize {
             0 => {}
-            1 => panic!("cannot log after main thread has exited"),
             n => {
                 let filter = mem::transmute::<_, &String>(n);
                 if !args.to_string().contains(filter) {
@@ -385,9 +382,6 @@ pub fn mod_enabled(level: u32, module: &str) -> bool {
     let _g = LOCK.lock();
     unsafe {
         assert!(DIRECTIVES as usize != 0);
-        assert!(DIRECTIVES as usize != 1,
-                "cannot log after the main thread has exited");
-
         enabled(level, module, (*DIRECTIVES).iter())
     }
 }
@@ -442,19 +436,6 @@ fn init() {
 
         assert!(DIRECTIVES.is_null());
         DIRECTIVES = Box::into_raw(box directives);
-
-        // Schedule the cleanup for the globals for when the runtime exits.
-        let _ = rt::at_exit(move || {
-            let _g = LOCK.lock();
-            assert!(!DIRECTIVES.is_null());
-            let _directives = Box::from_raw(DIRECTIVES);
-            DIRECTIVES = 1 as *mut _;
-
-            if !FILTER.is_null() {
-                let _filter = Box::from_raw(FILTER);
-                FILTER = 1 as *mut _;
-            }
-        });
     }
 }
 
diff --git a/src/libstd/collections/hash/table.rs b/src/libstd/collections/hash/table.rs
index e3601f1349c..f8bd791f681 100644
--- a/src/libstd/collections/hash/table.rs
+++ b/src/libstd/collections/hash/table.rs
@@ -8,23 +8,20 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use self::BucketState::*;
+use alloc::heap::{allocate, deallocate, EMPTY};
 
-use clone::Clone;
 use cmp;
 use hash::{Hash, Hasher};
-use iter::{Iterator, ExactSizeIterator};
-use marker::{Copy, Send, Sync, Sized, self};
+use marker;
 use mem::{align_of, size_of};
 use mem;
 use num::wrapping::OverflowingOps;
-use ops::{Deref, DerefMut, Drop};
-use option::Option;
-use option::Option::{Some, None};
+use ops::{Deref, DerefMut};
 use ptr::{self, Unique};
-use rt::heap::{allocate, deallocate, EMPTY};
 use collections::hash_state::HashState;
 
+use self::BucketState::*;
+
 const EMPTY_BUCKET: u64 = 0;
 
 /// The raw hashtable, providing safe-ish access to the unzipped and highly
diff --git a/src/libstd/io/lazy.rs b/src/libstd/io/lazy.rs
index 5424fec8110..65667f24dda 100644
--- a/src/libstd/io/lazy.rs
+++ b/src/libstd/io/lazy.rs
@@ -12,8 +12,8 @@ use prelude::v1::*;
 
 use cell::Cell;
 use ptr;
-use rt;
 use sync::{StaticMutex, Arc};
+use sys_common;
 
 pub struct Lazy<T> {
     lock: StaticMutex,
@@ -51,7 +51,7 @@ impl<T: Send + Sync + 'static> Lazy<T> {
         // `Arc` allocation in our own internal box (it will get deallocated by
         // the at exit handler). Otherwise we just return the freshly allocated
         // `Arc`.
-        let registered = rt::at_exit(move || {
+        let registered = sys_common::at_exit(move || {
             let g = self.lock.lock();
             let ptr = self.ptr.get();
             self.ptr.set(1 as *mut _);
diff --git a/src/libstd/panicking.rs b/src/libstd/panicking.rs
index bb4375c1b88..9715939d644 100644
--- a/src/libstd/panicking.rs
+++ b/src/libstd/panicking.rs
@@ -13,9 +13,10 @@ use io::prelude::*;
 
 use any::Any;
 use cell::RefCell;
-use rt::{backtrace, unwind};
 use sys::stdio::Stderr;
+use sys_common::backtrace;
 use sys_common::thread_info;
+use sys_common::unwind;
 
 thread_local! {
     pub static LOCAL_STDERR: RefCell<Option<Box<Write + Send>>> = {
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index 79f2d16fef4..5f5d5a69003 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -582,7 +582,7 @@ impl Child {
 /// to run.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn exit(code: i32) -> ! {
-    ::rt::cleanup();
+    ::sys_common::cleanup();
     ::sys::os::exit(code)
 }
 
diff --git a/src/libstd/rt.rs b/src/libstd/rt.rs
new file mode 100644
index 00000000000..8be0c6f3b3d
--- /dev/null
+++ b/src/libstd/rt.rs
@@ -0,0 +1,65 @@
+// 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.
+
+//! Runtime services
+//!
+//! The `rt` module provides a narrow set of runtime services,
+//! including the global heap (exported in `heap`) and unwinding and
+//! backtrace support. The APIs in this module are highly unstable,
+//! and should be considered as private implementation details for the
+//! time being.
+
+#![unstable(feature = "rt",
+            reason = "this public module should not exist and is highly likely \
+                      to disappear",
+            issue = "0")]
+#![doc(hidden)]
+
+use borrow::ToOwned;
+use mem;
+use sys;
+use sys_common::thread_info::{self, NewThread};
+use sys_common;
+use thread::{self, Thread};
+
+// Reexport some of our utilities which are expected by other crates.
+pub use sys_common::unwind::{begin_unwind, begin_unwind_fmt};
+
+#[cfg(not(test))]
+#[lang = "start"]
+fn lang_start(main: *const u8, argc: isize, argv: *const *const u8) -> isize {
+    sys::init();
+
+    let failed = unsafe {
+        let main_guard = sys::thread::guard::init();
+        sys::stack_overflow::init();
+
+        // Next, set up the current Thread with the guard information we just
+        // created. Note that this isn't necessary in general for new threads,
+        // but we just do this to name the main thread and to give it correct
+        // info about the stack bounds.
+        let thread: Thread = NewThread::new(Some("<main>".to_owned()));
+        thread_info::set(main_guard, thread);
+
+        // Store our args if necessary in a squirreled away location
+        sys_common::args::init(argc, argv);
+
+        // Let's run some code!
+        let res = thread::catch_panic(mem::transmute::<_, fn()>(main));
+        sys_common::cleanup();
+        res.is_err()
+    };
+
+    if failed {
+        101
+    } else {
+        0
+    }
+}
diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
deleted file mode 100644
index 9e7ed89bae1..00000000000
--- a/src/libstd/rt/backtrace.rs
+++ /dev/null
@@ -1,76 +0,0 @@
-// Copyright 2014 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.
-
-//! Simple backtrace functionality (to print on panic)
-
-#![allow(non_camel_case_types)]
-
-use env;
-use sync::atomic::{self, Ordering};
-
-pub use sys::backtrace::write;
-
-// For now logging is turned off by default, and this function checks to see
-// whether the magical environment variable is present to see if it's turned on.
-pub fn log_enabled() -> bool {
-    static ENABLED: atomic::AtomicIsize = atomic::AtomicIsize::new(0);
-    match ENABLED.load(Ordering::SeqCst) {
-        1 => return false,
-        2 => return true,
-        _ => {}
-    }
-
-    let val = match env::var_os("RUST_BACKTRACE") {
-        Some(..) => 2,
-        None => 1,
-    };
-    ENABLED.store(val, Ordering::SeqCst);
-    val == 2
-}
-
-#[cfg(test)]
-mod tests {
-    use prelude::v1::*;
-    use sys_common;
-    macro_rules! t { ($a:expr, $b:expr) => ({
-        let mut m = Vec::new();
-        sys_common::backtrace::demangle(&mut m, $a).unwrap();
-        assert_eq!(String::from_utf8(m).unwrap(), $b);
-    }) }
-
-    #[test]
-    fn demangle() {
-        t!("test", "test");
-        t!("_ZN4testE", "test");
-        t!("_ZN4test", "_ZN4test");
-        t!("_ZN4test1a2bcE", "test::a::bc");
-    }
-
-    #[test]
-    fn demangle_dollars() {
-        t!("_ZN4$RP$E", ")");
-        t!("_ZN8$RF$testE", "&test");
-        t!("_ZN8$BP$test4foobE", "*test::foob");
-        t!("_ZN9$u20$test4foobE", " test::foob");
-    }
-
-    #[test]
-    fn demangle_many_dollars() {
-        t!("_ZN13test$u20$test4foobE", "test test::foob");
-        t!("_ZN12test$BP$test4foobE", "test*test::foob");
-    }
-
-    #[test]
-    fn demangle_windows() {
-        t!("ZN4testE", "test");
-        t!("ZN13test$u20$test4foobE", "test test::foob");
-        t!("ZN12test$RF$test4foobE", "test&test::foob");
-    }
-}
diff --git a/src/libstd/rt/macros.rs b/src/libstd/rt/macros.rs
deleted file mode 100644
index 414ccc911af..00000000000
--- a/src/libstd/rt/macros.rs
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! Macros used by the runtime.
-//!
-//! These macros call functions which are only accessible in the `rt` module, so
-//! they aren't defined anywhere outside of the `rt` module.
-
-macro_rules! rterrln {
-    ($fmt:expr) => ( {
-        ::rt::util::dumb_print(format_args!(concat!($fmt, "\n")))
-    } );
-    ($fmt:expr, $($arg:expr),*) => ( {
-        ::rt::util::dumb_print(format_args!(concat!($fmt, "\n"), $($arg),*))
-    } )
-}
-
-// Some basic logging. Enabled by passing `--cfg rtdebug` to the libstd build.
-macro_rules! rtdebug {
-    ($arg:expr) => ( {
-        if cfg!(rtdebug) {
-            rterrln!($arg)
-        }
-    } );
-    ($str:expr, $($arg:expr),*) => ( {
-        if cfg!(rtdebug) {
-            rterrln!($str, $($arg),*)
-        }
-    })
-}
-
-macro_rules! rtassert {
-    ( $arg:expr ) => ( {
-        if ::rt::util::ENFORCE_SANITY {
-            if !$arg {
-                rtabort!(" assertion failed: {}", stringify!($arg));
-            }
-        }
-    } )
-}
-
-macro_rules! rtabort {
-    ($($arg:tt)*) => (::rt::util::abort(format_args!($($arg)*)))
-}
diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
deleted file mode 100644
index 95cba132201..00000000000
--- a/src/libstd/rt/mod.rs
+++ /dev/null
@@ -1,135 +0,0 @@
-// 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.
-
-//! Runtime services
-//!
-//! The `rt` module provides a narrow set of runtime services,
-//! including the global heap (exported in `heap`) and unwinding and
-//! backtrace support. The APIs in this module are highly unstable,
-//! and should be considered as private implementation details for the
-//! time being.
-
-#![unstable(feature = "rt",
-            reason = "this public module should not exist and is highly likely \
-                      to disappear",
-            issue = "0")]
-#![allow(missing_docs)]
-
-use prelude::v1::*;
-use sync::Once;
-use sys;
-use thread;
-
-// Reexport some of our utilities which are expected by other crates.
-pub use self::util::min_stack;
-pub use self::unwind::{begin_unwind, begin_unwind_fmt};
-
-// Reexport some functionality from liballoc.
-pub use alloc::heap;
-
-// Simple backtrace functionality (to print on panic)
-pub mod backtrace;
-
-// Internals
-#[macro_use]
-mod macros;
-
-// These should be refactored/moved/made private over time
-pub mod util;
-pub mod unwind;
-pub mod args;
-
-mod at_exit_imp;
-mod libunwind;
-
-mod dwarf;
-
-/// The default error code of the rust runtime if the main thread panics instead
-/// of exiting cleanly.
-pub const DEFAULT_ERROR_CODE: isize = 101;
-
-#[cfg(not(test))]
-#[lang = "start"]
-fn lang_start(main: *const u8, argc: isize, argv: *const *const u8) -> isize {
-    use prelude::v1::*;
-
-    use mem;
-    use rt;
-    use sys_common::thread_info::{self, NewThread};
-    use thread::Thread;
-
-    let failed = unsafe {
-        let main_guard = sys::thread::guard::init();
-        sys::stack_overflow::init();
-
-        // Next, set up the current Thread with the guard information we just
-        // created. Note that this isn't necessary in general for new threads,
-        // but we just do this to name the main thread and to give it correct
-        // info about the stack bounds.
-        let thread: Thread = NewThread::new(Some("<main>".to_owned()));
-        thread_info::set(main_guard, thread);
-
-        // By default, some platforms will send a *signal* when a EPIPE error
-        // would otherwise be delivered. This runtime doesn't install a SIGPIPE
-        // handler, causing it to kill the program, which isn't exactly what we
-        // want!
-        //
-        // Hence, we set SIGPIPE to ignore when the program starts up in order
-        // to prevent this problem.
-        #[cfg(windows)] fn ignore_sigpipe() {}
-        #[cfg(unix)] fn ignore_sigpipe() {
-            use libc;
-            use libc::funcs::posix01::signal::signal;
-            unsafe {
-                assert!(signal(libc::SIGPIPE, libc::SIG_IGN) != !0);
-            }
-        }
-        ignore_sigpipe();
-
-        // Store our args if necessary in a squirreled away location
-        args::init(argc, argv);
-
-        // And finally, let's run some code!
-        let res = thread::catch_panic(mem::transmute::<_, fn()>(main));
-        cleanup();
-        res.is_err()
-    };
-
-    // If the exit code wasn't set, then the try block must have panicked.
-    if failed {
-        rt::DEFAULT_ERROR_CODE
-    } else {
-        0
-    }
-}
-
-/// Enqueues a procedure to run when the main thread exits.
-///
-/// Currently these closures are only run once the main *Rust* thread exits.
-/// Once the `at_exit` handlers begin running, more may be enqueued, but not
-/// infinitely so. Eventually a handler registration will be forced to fail.
-///
-/// Returns `Ok` if the handler was successfully registered, meaning that the
-/// closure will be run once the main thread exits. Returns `Err` to indicate
-/// that the closure could not be registered, meaning that it is not scheduled
-/// to be run.
-pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
-    if at_exit_imp::push(Box::new(f)) {Ok(())} else {Err(())}
-}
-
-/// One-time runtime cleanup.
-pub fn cleanup() {
-    static CLEANUP: Once = Once::new();
-    CLEANUP.call_once(|| unsafe {
-        args::cleanup();
-        sys::stack_overflow::cleanup();
-        at_exit_imp::cleanup();
-    });
-}
diff --git a/src/libstd/rt/args.rs b/src/libstd/sys/common/args.rs
index 8de713aeac8..4cfddb036e9 100644
--- a/src/libstd/rt/args.rs
+++ b/src/libstd/sys/common/args.rs
@@ -19,6 +19,8 @@
 //!
 //! FIXME #7756: Would be nice for this to not exist.
 
+#![allow(dead_code)] // different code on OSX/linux/etc
+
 use vec::Vec;
 
 /// One-time global initialization.
@@ -27,14 +29,6 @@ pub unsafe fn init(argc: isize, argv: *const *const u8) { imp::init(argc, argv)
 /// One-time global cleanup.
 pub unsafe fn cleanup() { imp::cleanup() }
 
-/// Take the global arguments from global storage.
-pub fn take() -> Option<Vec<Vec<u8>>> { imp::take() }
-
-/// Give the global arguments to global storage.
-///
-/// It is an error if the arguments already exist.
-pub fn put(args: Vec<Vec<u8>>) { imp::put(args) }
-
 /// Make a clone of the global arguments.
 pub fn clone() -> Option<Vec<Vec<u8>>> { imp::clone() }
 
@@ -48,7 +42,7 @@ pub fn clone() -> Option<Vec<Vec<u8>>> { imp::clone() }
 mod imp {
     use prelude::v1::*;
 
-    use libc;
+    use libc::c_char;
     use mem;
     use ffi::CStr;
 
@@ -58,37 +52,26 @@ mod imp {
     static LOCK: StaticMutex = StaticMutex::new();
 
     pub unsafe fn init(argc: isize, argv: *const *const u8) {
-        let args = load_argc_and_argv(argc, argv);
-        put(args);
-    }
+        let args = (0..argc).map(|i| {
+            CStr::from_ptr(*argv.offset(i) as *const c_char).to_bytes().to_vec()
+        }).collect();
 
-    pub unsafe fn cleanup() {
-        take();
-    }
-
-    pub fn take() -> Option<Vec<Vec<u8>>> {
         let _guard = LOCK.lock();
-        unsafe {
-            let ptr = get_global_ptr();
-            let val = mem::replace(&mut *ptr, None);
-            val.as_ref().map(|s: &Box<Vec<Vec<u8>>>| (**s).clone())
-        }
+        let ptr = get_global_ptr();
+        assert!((*ptr).is_none());
+        (*ptr) = Some(box args);
     }
 
-    pub fn put(args: Vec<Vec<u8>>) {
+    pub unsafe fn cleanup() {
         let _guard = LOCK.lock();
-        unsafe {
-            let ptr = get_global_ptr();
-            rtassert!((*ptr).is_none());
-            (*ptr) = Some(box args.clone());
-        }
+        *get_global_ptr() = None;
     }
 
     pub fn clone() -> Option<Vec<Vec<u8>>> {
         let _guard = LOCK.lock();
         unsafe {
             let ptr = get_global_ptr();
-            (*ptr).as_ref().map(|s: &Box<Vec<Vec<u8>>>| (**s).clone())
+            (*ptr).as_ref().map(|s| (**s).clone())
         }
     }
 
@@ -96,42 +79,6 @@ mod imp {
         unsafe { mem::transmute(&GLOBAL_ARGS_PTR) }
     }
 
-    unsafe fn load_argc_and_argv(argc: isize,
-                                 argv: *const *const u8) -> Vec<Vec<u8>> {
-        let argv = argv as *const *const libc::c_char;
-        (0..argc).map(|i| {
-            CStr::from_ptr(*argv.offset(i)).to_bytes().to_vec()
-        }).collect()
-    }
-
-    #[cfg(test)]
-    mod tests {
-        use prelude::v1::*;
-
-        use super::*;
-
-        #[test]
-        fn smoke_test() {
-            // Preserve the actual global state.
-            let saved_value = take();
-
-            let expected = vec![
-                b"happy".to_vec(),
-                b"today?".to_vec(),
-            ];
-
-            put(expected.clone());
-            assert!(clone() == Some(expected.clone()));
-            assert!(take() == Some(expected.clone()));
-            assert!(take() == None);
-
-            // Restore the actual global state.
-            match saved_value {
-                Some(ref args) => put(args.clone()),
-                None => ()
-            }
-        }
-    }
 }
 
 #[cfg(any(target_os = "macos",
@@ -146,14 +93,6 @@ mod imp {
     pub fn cleanup() {
     }
 
-    pub fn take() -> Option<Vec<Vec<u8>>> {
-        panic!()
-    }
-
-    pub fn put(_args: Vec<Vec<u8>>) {
-        panic!()
-    }
-
     pub fn clone() -> Option<Vec<Vec<u8>>> {
         panic!()
     }
diff --git a/src/libstd/rt/at_exit_imp.rs b/src/libstd/sys/common/at_exit_imp.rs
index 7a1215bf382..b2683750d67 100644
--- a/src/libstd/rt/at_exit_imp.rs
+++ b/src/libstd/sys/common/at_exit_imp.rs
@@ -54,7 +54,7 @@ pub fn cleanup() {
             LOCK.unlock();
 
             // make sure we're not recursively cleaning up
-            rtassert!(queue as usize != 1);
+            assert!(queue as usize != 1);
 
             // If we never called init, not need to cleanup!
             if queue as usize != 0 {
diff --git a/src/libstd/sys/common/backtrace.rs b/src/libstd/sys/common/backtrace.rs
index 7845714e7f6..e7bda9a7ba2 100644
--- a/src/libstd/sys/common/backtrace.rs
+++ b/src/libstd/sys/common/backtrace.rs
@@ -8,10 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use io;
+use env;
 use io::prelude::*;
-use str;
+use io;
 use libc;
+use str;
+use sync::atomic::{self, Ordering};
+
+pub use sys::backtrace::write;
 
 #[cfg(target_pointer_width = "64")]
 pub const HEX_WIDTH: usize = 18;
@@ -19,6 +23,23 @@ pub const HEX_WIDTH: usize = 18;
 #[cfg(target_pointer_width = "32")]
 pub const HEX_WIDTH: usize = 10;
 
+// For now logging is turned off by default, and this function checks to see
+// whether the magical environment variable is present to see if it's turned on.
+pub fn log_enabled() -> bool {
+    static ENABLED: atomic::AtomicIsize = atomic::AtomicIsize::new(0);
+    match ENABLED.load(Ordering::SeqCst) {
+        1 => return false,
+        2 => return true,
+        _ => {}
+    }
+
+    let val = match env::var_os("RUST_BACKTRACE") {
+        Some(..) => 2,
+        None => 1,
+    };
+    ENABLED.store(val, Ordering::SeqCst);
+    val == 2
+}
 
 // These output functions should now be used everywhere to ensure consistency.
 pub fn output(w: &mut Write, idx: isize, addr: *mut libc::c_void,
@@ -163,3 +184,43 @@ pub fn demangle(writer: &mut Write, s: &str) -> io::Result<()> {
 
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use sys_common;
+    macro_rules! t { ($a:expr, $b:expr) => ({
+        let mut m = Vec::new();
+        sys_common::backtrace::demangle(&mut m, $a).unwrap();
+        assert_eq!(String::from_utf8(m).unwrap(), $b);
+    }) }
+
+    #[test]
+    fn demangle() {
+        t!("test", "test");
+        t!("_ZN4testE", "test");
+        t!("_ZN4test", "_ZN4test");
+        t!("_ZN4test1a2bcE", "test::a::bc");
+    }
+
+    #[test]
+    fn demangle_dollars() {
+        t!("_ZN4$RP$E", ")");
+        t!("_ZN8$RF$testE", "&test");
+        t!("_ZN8$BP$test4foobE", "*test::foob");
+        t!("_ZN9$u20$test4foobE", " test::foob");
+    }
+
+    #[test]
+    fn demangle_many_dollars() {
+        t!("_ZN13test$u20$test4foobE", "test test::foob");
+        t!("_ZN12test$BP$test4foobE", "test*test::foob");
+    }
+
+    #[test]
+    fn demangle_windows() {
+        t!("ZN4testE", "test");
+        t!("ZN13test$u20$test4foobE", "test test::foob");
+        t!("ZN12test$RF$test4foobE", "test&test::foob");
+    }
+}
diff --git a/src/libstd/rt/dwarf/eh.rs b/src/libstd/sys/common/dwarf/eh.rs
index f4799703d99..319be245bde 100644
--- a/src/libstd/rt/dwarf/eh.rs
+++ b/src/libstd/sys/common/dwarf/eh.rs
@@ -22,7 +22,7 @@
 #![allow(unused)]
 
 use prelude::v1::*;
-use rt::dwarf::DwarfReader;
+use sys_common::dwarf::DwarfReader;
 use core::mem;
 
 pub const DW_EH_PE_omit     : u8 = 0xFF;
diff --git a/src/libstd/rt/dwarf/mod.rs b/src/libstd/sys/common/dwarf/mod.rs
index 822826bcc83..822826bcc83 100644
--- a/src/libstd/rt/dwarf/mod.rs
+++ b/src/libstd/sys/common/dwarf/mod.rs
diff --git a/src/libstd/rt/libunwind.rs b/src/libstd/sys/common/libunwind.rs
index fde612014e9..fde612014e9 100644
--- a/src/libstd/rt/libunwind.rs
+++ b/src/libstd/sys/common/libunwind.rs
diff --git a/src/libstd/sys/common/mod.rs b/src/libstd/sys/common/mod.rs
index b8074235fb2..44c55d1e2c4 100644
--- a/src/libstd/sys/common/mod.rs
+++ b/src/libstd/sys/common/mod.rs
@@ -10,17 +10,39 @@
 
 #![allow(missing_docs)]
 
+use boxed::Box;
+use sync::Once;
+use sys;
+
+macro_rules! rtabort {
+    ($($t:tt)*) => (::sys_common::util::abort(format_args!($($t)*)))
+}
+
+macro_rules! rtassert {
+    ($e:expr) => ({
+        if !$e {
+            rtabort!(concat!("assertion failed: ", stringify!($e)))
+        }
+    })
+}
+
+pub mod args;
+pub mod at_exit_imp;
 pub mod backtrace;
 pub mod condvar;
+pub mod dwarf;
+pub mod io;
+pub mod libunwind;
 pub mod mutex;
 pub mod net;
-pub mod io;
 pub mod poison;
 pub mod remutex;
 pub mod rwlock;
 pub mod thread;
 pub mod thread_info;
 pub mod thread_local;
+pub mod unwind;
+pub mod util;
 pub mod wtf8;
 
 #[cfg(any(all(unix, not(any(target_os = "macos", target_os = "ios"))),
@@ -52,3 +74,27 @@ pub trait IntoInner<Inner> {
 pub trait FromInner<Inner> {
     fn from_inner(inner: Inner) -> Self;
 }
+
+/// Enqueues a procedure to run when the main thread exits.
+///
+/// Currently these closures are only run once the main *Rust* thread exits.
+/// Once the `at_exit` handlers begin running, more may be enqueued, but not
+/// infinitely so. Eventually a handler registration will be forced to fail.
+///
+/// Returns `Ok` if the handler was successfully registered, meaning that the
+/// closure will be run once the main thread exits. Returns `Err` to indicate
+/// that the closure could not be registered, meaning that it is not scheduled
+/// to be run.
+pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
+    if at_exit_imp::push(Box::new(f)) {Ok(())} else {Err(())}
+}
+
+/// One-time runtime cleanup.
+pub fn cleanup() {
+    static CLEANUP: Once = Once::new();
+    CLEANUP.call_once(|| unsafe {
+        args::cleanup();
+        sys::stack_overflow::cleanup();
+        at_exit_imp::cleanup();
+    });
+}
diff --git a/src/libstd/rt/unwind/gcc.rs b/src/libstd/sys/common/unwind/gcc.rs
index 55deb048b7e..361cef08c11 100644
--- a/src/libstd/rt/unwind/gcc.rs
+++ b/src/libstd/sys/common/unwind/gcc.rs
@@ -13,7 +13,7 @@
 use prelude::v1::*;
 
 use any::Any;
-use rt::libunwind as uw;
+use sys_common::libunwind as uw;
 
 struct Exception {
     uwe: uw::_Unwind_Exception,
@@ -35,7 +35,6 @@ pub unsafe fn panic(data: Box<Any + Send + 'static>) -> ! {
 
     extern fn exception_cleanup(_unwind_code: uw::_Unwind_Reason_Code,
                                 exception: *mut uw::_Unwind_Exception) {
-        rtdebug!("exception_cleanup()");
         unsafe {
             let _: Box<Exception> = Box::from_raw(exception as *mut Exception);
         }
@@ -44,7 +43,6 @@ pub unsafe fn panic(data: Box<Any + Send + 'static>) -> ! {
 
 pub unsafe fn cleanup(ptr: *mut u8) -> Box<Any + Send + 'static> {
     let my_ep = ptr as *mut Exception;
-    rtdebug!("caught {}", (*my_ep).uwe.exception_class);
     let cause = (*my_ep).cause.take();
     uw::_Unwind_DeleteException(ptr as *mut _);
     cause.unwrap()
@@ -80,7 +78,7 @@ fn rust_exception_class() -> uw::_Unwind_Exception_Class {
           not(all(windows, target_arch = "x86_64")),
           not(test)))]
 pub mod eabi {
-    use rt::libunwind as uw;
+    use sys_common::libunwind as uw;
     use libc::c_int;
 
     extern {
@@ -136,7 +134,7 @@ pub mod eabi {
 
 #[cfg(all(target_os = "ios", target_arch = "arm", not(test)))]
 pub mod eabi {
-    use rt::libunwind as uw;
+    use sys_common::libunwind as uw;
     use libc::c_int;
 
     extern {
@@ -191,7 +189,7 @@ pub mod eabi {
 // but otherwise works the same.
 #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(test)))]
 pub mod eabi {
-    use rt::libunwind as uw;
+    use sys_common::libunwind as uw;
     use libc::c_int;
 
     extern {
diff --git a/src/libstd/rt/unwind/mod.rs b/src/libstd/sys/common/unwind/mod.rs
index 4feb2d49a98..ff93d0526b7 100644
--- a/src/libstd/rt/unwind/mod.rs
+++ b/src/libstd/sys/common/unwind/mod.rs
@@ -184,7 +184,6 @@ pub fn panicking() -> bool {
 #[no_mangle]
 #[allow(private_no_mangle_fns)]
 fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
-    rtdebug!("begin_unwind()");
     unsafe {
         imp::panic(cause)
     }
@@ -288,7 +287,8 @@ fn begin_unwind_inner(msg: Box<Any + Send>,
         // have limited options. Currently our preference is to
         // just abort. In the future we may consider resuming
         // unwinding or otherwise exiting the thread cleanly.
-        rterrln!("thread panicked while panicking. aborting.");
+        super::util::dumb_print(format_args!("thread panicked while panicking. \
+                                              aborting."));
         unsafe { intrinsics::abort() }
     }
     PANICKING.with(|s| s.set(true));
diff --git a/src/libstd/rt/unwind/seh.rs b/src/libstd/sys/common/unwind/seh.rs
index 8c793758166..a201e406a23 100644
--- a/src/libstd/rt/unwind/seh.rs
+++ b/src/libstd/sys/common/unwind/seh.rs
@@ -135,10 +135,11 @@ fn rust_eh_personality() {
 // This function just takes a look at the current EXCEPTION_RECORD being thrown
 // to ensure that it's code is RUST_PANIC, which was set by the call to
 // `RaiseException` above in the `panic` function.
-#[no_mangle]
 #[lang = "msvc_try_filter"]
-pub extern fn __rust_try_filter(eh_ptrs: *mut EXCEPTION_POINTERS,
-                                _rbp: *mut u8) -> i32 {
+#[linkage = "external"]
+#[allow(private_no_mangle_fns)]
+extern fn __rust_try_filter(eh_ptrs: *mut EXCEPTION_POINTERS,
+                            _rbp: *mut u8) -> i32 {
     unsafe {
         ((*(*eh_ptrs).ExceptionRecord).ExceptionCode == RUST_PANIC) as i32
     }
diff --git a/src/libstd/rt/unwind/seh64_gnu.rs b/src/libstd/sys/common/unwind/seh64_gnu.rs
index 78f969bfbeb..4d23794de24 100644
--- a/src/libstd/rt/unwind/seh64_gnu.rs
+++ b/src/libstd/sys/common/unwind/seh64_gnu.rs
@@ -18,7 +18,7 @@ use prelude::v1::*;
 
 use any::Any;
 use self::EXCEPTION_DISPOSITION::*;
-use rt::dwarf::eh;
+use sys_common::dwarf::eh;
 use core::mem;
 use core::ptr;
 use libc::{c_void, c_ulonglong, DWORD, LPVOID};
@@ -114,7 +114,6 @@ struct PanicData {
 pub unsafe fn panic(data: Box<Any + Send + 'static>) -> ! {
     let panic_ctx = Box::new(PanicData { data: data });
     let params = [Box::into_raw(panic_ctx) as ULONG_PTR];
-    rtdebug!("panic: ctx={:X}", params[0]);
     RaiseException(RUST_PANIC,
                    EXCEPTION_NONCONTINUABLE,
                    params.len() as DWORD,
@@ -123,7 +122,6 @@ pub unsafe fn panic(data: Box<Any + Send + 'static>) -> ! {
 }
 
 pub unsafe fn cleanup(ptr: *mut u8) -> Box<Any + Send + 'static> {
-    rtdebug!("cleanup: ctx={:X}", ptr as usize);
     let panic_ctx = Box::from_raw(ptr as *mut PanicData);
     return panic_ctx.data;
 }
@@ -174,15 +172,10 @@ unsafe extern fn rust_eh_personality(
 {
     let er = &*exceptionRecord;
     let dc = &*dispatcherContext;
-    rtdebug!("rust_eh_personality: code={:X}, flags={:X}, frame={:X}, ip={:X}",
-        er.ExceptionCode, er.ExceptionFlags,
-        establisherFrame as usize, dc.ControlPc as usize);
 
     if er.ExceptionFlags & EXCEPTION_UNWIND == 0 { // we are in the dispatch phase
         if er.ExceptionCode == RUST_PANIC {
             if let Some(lpad) = find_landing_pad(dc) {
-                rtdebug!("unwinding to landing pad {:X}", lpad);
-
                 RtlUnwindEx(establisherFrame,
                             lpad as LPVOID,
                             exceptionRecord,
@@ -206,7 +199,6 @@ unsafe extern fn rust_eh_personality(
 #[lang = "eh_unwind_resume"]
 #[cfg(not(test))]
 unsafe extern fn rust_eh_unwind_resume(panic_ctx: LPVOID) {
-    rtdebug!("rust_eh_unwind_resume: ctx={:X}", panic_ctx as usize);
     let params = [panic_ctx as ULONG_PTR];
     RaiseException(RUST_PANIC,
                    EXCEPTION_NONCONTINUABLE,
diff --git a/src/libstd/rt/util.rs b/src/libstd/sys/common/util.rs
index 23a3c3e38c4..979f1f48669 100644
--- a/src/libstd/rt/util.rs
+++ b/src/libstd/sys/common/util.rs
@@ -8,13 +8,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use io::prelude::*;
-
 use env;
 use fmt;
 use intrinsics;
+use io::prelude::*;
 use sync::atomic::{self, Ordering};
 use sys::stdio::Stderr;
+use thread;
 
 pub fn min_stack() -> usize {
     static MIN: atomic::AtomicUsize = atomic::AtomicUsize::new(0);
@@ -30,24 +30,17 @@ pub fn min_stack() -> usize {
     amt
 }
 
-// Indicates whether we should perform expensive sanity checks, including rtassert!
-//
-// FIXME: Once the runtime matures remove the `true` below to turn off rtassert,
-//        etc.
-pub const ENFORCE_SANITY: bool = true || !cfg!(rtopt) || cfg!(rtdebug) ||
-                                  cfg!(rtassert);
-
 pub fn dumb_print(args: fmt::Arguments) {
     let _ = Stderr::new().map(|mut stderr| stderr.write_fmt(args));
 }
 
 pub fn abort(args: fmt::Arguments) -> ! {
-    rterrln!("fatal runtime error: {}", args);
+    dumb_print(format_args!("fatal runtime error: {}", args));
     unsafe { intrinsics::abort(); }
 }
 
+#[allow(dead_code)] // stack overflow detection not enabled on all platforms
 pub unsafe fn report_overflow() {
-    use thread;
-    rterrln!("\nthread '{}' has overflowed its stack",
-             thread::current().name().unwrap_or("<unknown>"));
+    dumb_print(format_args!("\nthread '{}' has overflowed its stack",
+                            thread::current().name().unwrap_or("<unknown>")));
 }
diff --git a/src/libstd/sys/unix/mod.rs b/src/libstd/sys/unix/mod.rs
index bbed42cc31d..964bc08ff4e 100644
--- a/src/libstd/sys/unix/mod.rs
+++ b/src/libstd/sys/unix/mod.rs
@@ -12,6 +12,7 @@
 #![allow(non_camel_case_types)]
 
 use io::{self, ErrorKind};
+use libc::funcs::posix01::signal::signal;
 use libc;
 use num::One;
 use ops::Neg;
@@ -47,6 +48,19 @@ pub mod thread_local;
 pub mod time;
 pub mod stdio;
 
+pub fn init() {
+    // By default, some platforms will send a *signal* when a EPIPE error
+    // would otherwise be delivered. This runtime doesn't install a SIGPIPE
+    // handler, causing it to kill the program, which isn't exactly what we
+    // want!
+    //
+    // Hence, we set SIGPIPE to ignore when the program starts up in order
+    // to prevent this problem.
+    unsafe {
+        assert!(signal(libc::SIGPIPE, libc::SIG_IGN) != !0);
+    }
+}
+
 pub fn decode_error_kind(errno: i32) -> ErrorKind {
     match errno as libc::c_int {
         libc::ECONNREFUSED => ErrorKind::ConnectionRefused,
diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index af0d8da05f4..94c4d04ea30 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -358,8 +358,8 @@ pub fn args() -> Args {
           target_os = "netbsd",
           target_os = "openbsd"))]
 pub fn args() -> Args {
-    use rt;
-    let bytes = rt::args::clone().unwrap_or(Vec::new());
+    use sys_common;
+    let bytes = sys_common::args::clone().unwrap_or(Vec::new());
     let v: Vec<OsString> = bytes.into_iter().map(|v| {
         OsStringExt::from_vec(v)
     }).collect();
diff --git a/src/libstd/sys/unix/stack_overflow.rs b/src/libstd/sys/unix/stack_overflow.rs
index de9e8cf97e6..441313bc639 100644
--- a/src/libstd/sys/unix/stack_overflow.rs
+++ b/src/libstd/sys/unix/stack_overflow.rs
@@ -38,7 +38,7 @@ impl Drop for Handler {
           target_os = "openbsd"))]
 mod imp {
     use super::Handler;
-    use rt::util::report_overflow;
+    use sys_common::util::report_overflow;
     use mem;
     use ptr;
     use sys::c::{siginfo, sigaction, SIGBUS, SIG_DFL,
diff --git a/src/libstd/sys/windows/mod.rs b/src/libstd/sys/windows/mod.rs
index 732e2e65864..04bb5e5ea38 100644
--- a/src/libstd/sys/windows/mod.rs
+++ b/src/libstd/sys/windows/mod.rs
@@ -43,6 +43,8 @@ pub mod thread_local;
 pub mod time;
 pub mod stdio;
 
+pub fn init() {}
+
 pub fn decode_error_kind(errno: i32) -> ErrorKind {
     match errno as libc::c_int {
         libc::ERROR_ACCESS_DENIED => ErrorKind::PermissionDenied,
diff --git a/src/libstd/sys/windows/net.rs b/src/libstd/sys/windows/net.rs
index e62b2d8cb18..998b4fcb1a1 100644
--- a/src/libstd/sys/windows/net.rs
+++ b/src/libstd/sys/windows/net.rs
@@ -16,11 +16,10 @@ use net::SocketAddr;
 use num::One;
 use ops::Neg;
 use ptr;
-use rt;
 use sync::Once;
 use sys;
 use sys::c;
-use sys_common::{AsInner, FromInner, IntoInner};
+use sys_common::{self, AsInner, FromInner, IntoInner};
 use sys_common::net::{setsockopt, getsockopt};
 use time::Duration;
 
@@ -39,7 +38,7 @@ pub fn init() {
                                 &mut data);
         assert_eq!(ret, 0);
 
-        let _ = rt::at_exit(|| { c::WSACleanup(); });
+        let _ = sys_common::at_exit(|| { c::WSACleanup(); });
     });
 }
 
diff --git a/src/libstd/sys/windows/stack_overflow.rs b/src/libstd/sys/windows/stack_overflow.rs
index f93f7c756de..d1c2144ef0d 100644
--- a/src/libstd/sys/windows/stack_overflow.rs
+++ b/src/libstd/sys/windows/stack_overflow.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use libc::{self, LONG};
-use rt::util::report_overflow;
+use sys_common::util::report_overflow;
 use sys::c;
 
 pub struct Handler;
diff --git a/src/libstd/sys/windows/thread_local.rs b/src/libstd/sys/windows/thread_local.rs
index 17bc7ee8876..c544eec7fce 100644
--- a/src/libstd/sys/windows/thread_local.rs
+++ b/src/libstd/sys/windows/thread_local.rs
@@ -13,7 +13,7 @@ use prelude::v1::*;
 use libc::types::os::arch::extra::{DWORD, LPVOID, BOOL};
 
 use ptr;
-use rt;
+use sys_common;
 use sys_common::mutex::Mutex;
 
 pub type Key = DWORD;
@@ -133,7 +133,7 @@ unsafe fn init_dtors() {
 
     let dtors = box Vec::<(Key, Dtor)>::new();
 
-    let res = rt::at_exit(move|| {
+    let res = sys_common::at_exit(move|| {
         DTOR_LOCK.lock();
         let dtors = DTORS;
         DTORS = 1 as *mut _;
diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs
index 3a4c3e7eef1..2b7a3deceb7 100644
--- a/src/libstd/thread/mod.rs
+++ b/src/libstd/thread/mod.rs
@@ -167,10 +167,11 @@ use any::Any;
 use cell::UnsafeCell;
 use fmt;
 use io;
-use rt::{self, unwind};
 use sync::{Mutex, Condvar, Arc};
 use sys::thread as imp;
 use sys_common::thread_info;
+use sys_common::unwind;
+use sys_common::util;
 use time::Duration;
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -260,7 +261,7 @@ impl Builder {
                                        -> io::Result<JoinInner<T>> {
         let Builder { name, stack_size } = self;
 
-        let stack_size = stack_size.unwrap_or(rt::min_stack());
+        let stack_size = stack_size.unwrap_or(util::min_stack());
 
         let my_thread = Thread::new(name);
         let their_thread = my_thread.clone();
@@ -383,7 +384,7 @@ pub fn catch_panic<F, R>(f: F) -> Result<R>
     let mut result = None;
     unsafe {
         let result = &mut result;
-        try!(::rt::unwind::try(move || *result = Some(f())))
+        try!(unwind::try(move || *result = Some(f())))
     }
     Ok(result.unwrap())
 }