1 files changed, 57 insertions, 0 deletions
diff --git a/src/libstd/sys/unix/backtrace/tracing/backtrace_fn.rs b/src/libstd/sys/unix/backtrace/tracing/backtrace_fn.rs
new file mode 100644
index 00000000000..2865abb254c
--- /dev/null
+++ b/src/libstd/sys/unix/backtrace/tracing/backtrace_fn.rs
@@ -0,0 +1,57 @@
+// Copyright 2014-2015 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.
+
+/// As always - iOS on arm uses SjLj exceptions and
+/// _Unwind_Backtrace is even not available there. Still,
+/// backtraces could be extracted using a backtrace function,
+/// which thanks god is public
+///
+/// As mentioned in a huge comment block in `super::super`, backtrace
+/// doesn't play well with green threads, so while it is extremely nice and
+/// simple to use it should be used only on iOS devices as the only viable
+/// option.
+
+use io;
+use io::prelude::*;
+use iter::Iterator;
+use libc;
+use mem;
+use result::Result::Ok;
+use sync::StaticMutex;
+
+use super::printer::print;
+
+#[inline(never)]
+pub fn write(w: &mut Write) -> io::Result<()> {
+    use mem;
+
+    extern {
+        fn backtrace(buf: *mut *mut libc::c_void,
+                     sz: libc::c_int) -> libc::c_int;
+    }
+
+    // while it doesn't requires lock for work as everything is
+    // local, it still displays much nicer backtraces when a
+    // couple of threads panic simultaneously
+    static LOCK: StaticMutex = StaticMutex::new();
+    let _g = LOCK.lock();
+
+    try!(writeln!(w, "stack backtrace:"));
+    // 100 lines should be enough
+    const SIZE: usize = 100;
+    let mut buf: [*mut libc::c_void; SIZE] = unsafe { mem::zeroed() };
+    let cnt = unsafe { backtrace(buf.as_mut_ptr(), SIZE as libc::c_int) as usize};
+
+    // skipping the first one as it is write itself
+    for i in 1..cnt {
+        try!(print(w, i as isize, buf[i], buf[i]))
+    }
+    Ok(())
+}