1 // Copyright 2016 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Implementation of Rust panics via process aborts
13 //! When compared to the implementation via unwinding, this crate is *much*
14 //! simpler! That being said, it's not quite as versatile, but here goes!
17 #![unstable(feature = "panic_abort", issue = "32837")]
18 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
19 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
20 html_root_url = "https://doc.rust-lang.org/nightly/",
21 issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
24 #![allow(unused_features)]
26 #![feature(core_intrinsics)]
28 #![feature(panic_runtime)]
29 #![feature(staged_api)]
30 #![feature(rustc_attrs)]
32 // Rust's "try" function, but if we're aborting on panics we just call the
33 // function as there's nothing else we need to do here.
35 #[rustc_std_internal_symbol]
36 pub unsafe extern fn __rust_maybe_catch_panic(f: fn(*mut u8),
38 _data_ptr: *mut usize,
39 _vtable_ptr: *mut usize) -> u32 {
44 // "Leak" the payload and shim to the relevant abort on the platform in
47 // For Unix we just use `abort` from libc as it'll trigger debuggers, core
48 // dumps, etc, as one might expect. On Windows, however, the best option we have
49 // is the `__fastfail` intrinsics, but that's unfortunately not defined in LLVM,
50 // and the `RaiseFailFastException` function isn't available until Windows 7
51 // which would break compat with XP. For now just use `intrinsics::abort` which
52 // will kill us with an illegal instruction, which will do a good enough job for
55 #[rustc_std_internal_symbol]
56 pub unsafe extern fn __rust_start_panic(_data: usize, _vtable: usize) -> u32 {
59 #[cfg(any(unix, target_os = "cloudabi"))]
60 unsafe fn abort() -> ! {
65 #[cfg(any(target_os = "redox",
67 all(target_arch = "wasm32", not(target_os = "emscripten"))))]
68 unsafe fn abort() -> ! {
69 core::intrinsics::abort();
73 // This... is a bit of an oddity. The tl;dr; is that this is required to link
74 // correctly, the longer explanation is below.
76 // Right now the binaries of libcore/libstd that we ship are all compiled with
77 // `-C panic=unwind`. This is done to ensure that the binaries are maximally
78 // compatible with as many situations as possible. The compiler, however,
79 // requires a "personality function" for all functions compiled with `-C
80 // panic=unwind`. This personality function is hardcoded to the symbol
81 // `rust_eh_personality` and is defined by the `eh_personality` lang item.
83 // So... why not just define that lang item here? Good question! The way that
84 // panic runtimes are linked in is actually a little subtle in that they're
85 // "sort of" in the compiler's crate store, but only actually linked if another
86 // isn't actually linked. This ends up meaning that both this crate and the
87 // panic_unwind crate can appear in the compiler's crate store, and if both
88 // define the `eh_personality` lang item then that'll hit an error.
90 // To handle this the compiler only requires the `eh_personality` is defined if
91 // the panic runtime being linked in is the unwinding runtime, and otherwise
92 // it's not required to be defined (rightfully so). In this case, however, this
93 // library just defines this symbol so there's at least some personality
96 // Essentially this symbol is just defined to get wired up to libcore/libstd
97 // binaries, but it should never be called as we don't link in an unwinding
99 pub mod personalities {
101 #[cfg(not(all(target_os = "windows",
103 target_arch = "x86_64")))]
104 pub extern fn rust_eh_personality() {}
106 // On x86_64-pc-windows-gnu we use our own personality function that needs
107 // to return `ExceptionContinueSearch` as we're passing on all our frames.
109 #[cfg(all(target_os = "windows",
111 target_arch = "x86_64"))]
112 pub extern fn rust_eh_personality(_record: usize,
115 _dispatcher: usize) -> u32 {
116 1 // `ExceptionContinueSearch`
119 // Similar to above, this corresponds to the `eh_unwind_resume` lang item
120 // that's only used on Windows currently.
122 // Note that we don't execute landing pads, so this is never called, so it's
125 #[cfg(all(target_os = "windows", target_env = "gnu"))]
126 pub extern fn rust_eh_unwind_resume() {}
128 // These two are called by our startup objects on i686-pc-windows-gnu, but
129 // they don't need to do anything so the bodies are nops.
131 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
132 pub extern fn rust_eh_register_frames() {}
134 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
135 pub extern fn rust_eh_unregister_frames() {}