diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index 78a467e3657..94408072932 100644
--- a/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@ -79,6 +79,7 @@
 #![feature(optin_builtin_traits)]
 #![feature(reflect)]
 #![feature(rustc_attrs)]
+#![feature(unwind_attributes)]
 #![cfg_attr(stage0, feature(simd))]
 #![cfg_attr(not(stage0), feature(repr_simd, platform_intrinsics))]
 #![feature(staged_api)]
diff --git a/src/libcore/panicking.rs b/src/libcore/panicking.rs
index b443ae0636f..93ddfa72f63 100644
--- a/src/libcore/panicking.rs
+++ b/src/libcore/panicking.rs
@@ -62,6 +62,7 @@ pub fn panic_fmt(fmt: fmt::Arguments, file_line: &(&'static str, u32)) -> ! {
     #[allow(improper_ctypes)]
     extern {
         #[lang = "panic_fmt"]
+        #[unwind]
         fn panic_impl(fmt: fmt::Arguments, file: &'static str, line: u32) -> !;
     }
     let (file, line) = *file_line;
diff --git a/src/librustc_trans/trans/foreign.rs b/src/librustc_trans/trans/foreign.rs
index 9a561249594..cbb092aa4eb 100644
--- a/src/librustc_trans/trans/foreign.rs
+++ b/src/librustc_trans/trans/foreign.rs
@@ -211,6 +211,7 @@ pub fn register_foreign_item_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     let llfn_ty = lltype_for_fn_from_foreign_types(ccx, &tys);
 
     let llfn = get_extern_fn(ccx, &mut *ccx.externs().borrow_mut(), name, cc, llfn_ty, fty);
+    attributes::unwind(llfn, false);
     add_argument_attributes(&tys, llfn);
     attributes::from_fn_attrs(ccx, attrs, llfn);
     llfn
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index fca4c66112e..dc370d8382a 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -243,6 +243,7 @@
 #![feature(unique)]
 #![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(decode_utf16)]
+#![feature(unwind_attributes)]
 #![feature(vec_push_all)]
 #![feature(vec_resize)]
 #![feature(wrapping)]
diff --git a/src/libstd/sys/common/libunwind.rs b/src/libstd/sys/common/libunwind.rs
index fde612014e9..c6bffb0f733 100644
--- a/src/libstd/sys/common/libunwind.rs
+++ b/src/libstd/sys/common/libunwind.rs
@@ -124,10 +124,12 @@ extern "C" {
     // iOS on armv7 uses SjLj exceptions and requires to link
     // against corresponding routine (..._SjLj_...)
     #[cfg(not(all(target_os = "ios", target_arch = "arm")))]
+    #[unwind]
     pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception)
                                   -> _Unwind_Reason_Code;
 
     #[cfg(all(target_os = "ios", target_arch = "arm"))]
+    #[unwind]
     fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception)
                                    -> _Unwind_Reason_Code;
 
diff --git a/src/libstd/sys/common/unwind/mod.rs b/src/libstd/sys/common/unwind/mod.rs
index ff93d0526b7..738681c3cfe 100644
--- a/src/libstd/sys/common/unwind/mod.rs
+++ b/src/libstd/sys/common/unwind/mod.rs
@@ -192,6 +192,7 @@ fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
 #[cfg(not(test))]
 /// Entry point of panic from the libcore crate.
 #[lang = "panic_fmt"]
+#[unwind]
 pub extern fn rust_begin_unwind(msg: fmt::Arguments,
                                 file: &'static str, line: u32) -> ! {
     begin_unwind_fmt(msg, &(file, line))
diff --git a/src/libstd/sys/common/unwind/seh.rs b/src/libstd/sys/common/unwind/seh.rs
index a201e406a23..a89e8b499ac 100644
--- a/src/libstd/sys/common/unwind/seh.rs
+++ b/src/libstd/sys/common/unwind/seh.rs
@@ -62,6 +62,7 @@ static PANIC_DATA: StaticKey = StaticKey::new(None);
 
 // This function is provided by kernel32.dll
 extern "system" {
+    #[unwind]
     fn RaiseException(dwExceptionCode: DWORD,
                       dwExceptionFlags: DWORD,
                       nNumberOfArguments: DWORD,
diff --git a/src/libstd/sys/common/unwind/seh64_gnu.rs b/src/libstd/sys/common/unwind/seh64_gnu.rs
index 4d23794de24..9478678fda9 100644
--- a/src/libstd/sys/common/unwind/seh64_gnu.rs
+++ b/src/libstd/sys/common/unwind/seh64_gnu.rs
@@ -93,6 +93,7 @@ pub enum EXCEPTION_DISPOSITION {
 
 // From kernel32.dll
 extern "system" {
+    #[unwind]
     fn RaiseException(dwExceptionCode: DWORD,
                       dwExceptionFlags: DWORD,
                       nNumberOfArguments: DWORD,
@@ -198,6 +199,7 @@ unsafe extern fn rust_eh_personality(
 
 #[lang = "eh_unwind_resume"]
 #[cfg(not(test))]
+#[unwind]
 unsafe extern fn rust_eh_unwind_resume(panic_ctx: LPVOID) {
     let params = [panic_ctx as ULONG_PTR];
     RaiseException(RUST_PANIC,
diff --git a/src/test/codegen/extern-functions.rs b/src/test/codegen/extern-functions.rs
new file mode 100644
index 00000000000..4c30b5ce02f
--- /dev/null
+++ b/src/test/codegen/extern-functions.rs
@@ -0,0 +1,23 @@
+// Copyright 2015 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.
+
+// compile-flags: -C no-prepopulate-passes
+
+#![feature(unwind_attributes)]
+
+extern {
+// CHECK: Function Attrs: nounwind
+// CHECK-NEXT: declare void @extern_fn
+    fn extern_fn();
+// CHECK-NOT: Function Attrs: nounwind
+// CHECK: declare void @unwinding_extern_fn
+    #[unwind]
+    fn unwinding_extern_fn();
+}