0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::_print
             at libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at libstd/sys_common/backtrace.rs:59
             at libstd/panicking.rs:380
   3: std::panicking::default_hook
             at libstd/panicking.rs:396
   4: std::panicking::begin_panic
             at libstd/panicking.rs:576
   5: std::panicking::begin_panic
             at libstd/panicking.rs:537
   6: std::panicking::try::do_call
             at libstd/panicking.rs:521
   7: bootstrap::compile::run_cargo
             at bootstrap/compile.rs:1096
   8: bootstrap::compile::copy_apple_sanitizer_dylibs
             at bootstrap/compile.rs:370
   9: bootstrap::builder::Builder::ensure
             at bootstrap/builder.rs:846
  10: bootstrap::test::testdir
             at bootstrap/test.rs:831
  11: bootstrap::builder::Builder::ensure
             at bootstrap/builder.rs:846
  12: <bootstrap::test::Ui as core::clone::Clone>::clone
             at bootstrap/test.rs:601
  13: bootstrap::builder::Builder::ensure
             at bootstrap/builder.rs:846
  14: <bootstrap::test::Ui as core::clone::Clone>::clone
             at bootstrap/test.rs:594
  15: bootstrap::builder::StepDescription::maybe_run
             at bootstrap/builder.rs:185
  16: bootstrap::builder::StepDescription::run
             at bootstrap/builder.rs:215
  17: bootstrap::builder::Builder::run
             at bootstrap/builder.rs:410
  18: bootstrap::Crate::local_path
             at bootstrap/lib.rs:392
  19: bootstrap::main
             at bootstrap/bin/main.rs:29
  20: std::rt::lang_start::{{closure}}
             at /Users/travis/build/rust-lang/rust/src/libstd/rt.rs:74
  21: std::panicking::try::do_call
             at libstd/rt.rs:59
             at libstd/panicking.rs:479
  22: panic_unwind::dwarf::eh::read_encoded_pointer
             at libpanic_unwind/lib.rs:102
  23: rust_panic
             at libstd/panicking.rs:458
             at libstd/panic.rs:358
             at libstd/rt.rs:58
  24: std::rt::lang_start
             at /Users/travis/build/rust-lang/rust/src/libstd/rt.rs:74
  25: bootstrap::main