1 //! Implementation of Rust panics via process aborts
3 //! When compared to the implementation via unwinding, this crate is *much*
4 //! simpler! That being said, it's not quite as versatile, but here goes!
7 #![unstable(feature = "panic_abort", issue = "32837")]
9 html_root_url = "https://doc.rust-lang.org/nightly/",
10 issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/"
13 #![allow(unused_features)]
14 #![feature(core_intrinsics)]
17 #![feature(panic_runtime)]
18 #![feature(staged_api)]
19 #![feature(rustc_attrs)]
21 // Rust's "try" function, but if we're aborting on panics we just call the
22 // function as there's nothing else we need to do here.
23 #[rustc_std_internal_symbol]
24 pub unsafe extern "C" fn __rust_maybe_catch_panic(
27 _data_ptr: *mut usize,
28 _vtable_ptr: *mut usize,
34 // "Leak" the payload and shim to the relevant abort on the platform in
37 // For Unix we just use `abort` from libc as it'll trigger debuggers, core
38 // dumps, etc, as one might expect. On Windows, however, the best option we have
39 // is the `__fastfail` intrinsics, but that's unfortunately not defined in LLVM,
40 // and the `RaiseFailFastException` function isn't available until Windows 7
41 // which would break compat with XP. For now just use `intrinsics::abort` which
42 // will kill us with an illegal instruction, which will do a good enough job for
44 #[rustc_std_internal_symbol]
45 pub unsafe extern "C" fn __rust_start_panic(_payload: usize) -> u32 {
48 #[cfg(any(unix, target_os = "cloudabi"))]
49 unsafe fn abort() -> ! {
53 #[cfg(any(windows, all(target_arch = "wasm32", not(target_os = "emscripten"))))]
54 unsafe fn abort() -> ! {
55 core::intrinsics::abort();
58 #[cfg(any(target_os = "hermit", all(target_vendor = "fortanix", target_env = "sgx")))]
59 unsafe fn abort() -> ! {
60 // call std::sys::abort_internal
62 pub fn __rust_abort() -> !;
68 // This... is a bit of an oddity. The tl;dr; is that this is required to link
69 // correctly, the longer explanation is below.
71 // Right now the binaries of libcore/libstd that we ship are all compiled with
72 // `-C panic=unwind`. This is done to ensure that the binaries are maximally
73 // compatible with as many situations as possible. The compiler, however,
74 // requires a "personality function" for all functions compiled with `-C
75 // panic=unwind`. This personality function is hardcoded to the symbol
76 // `rust_eh_personality` and is defined by the `eh_personality` lang item.
78 // So... why not just define that lang item here? Good question! The way that
79 // panic runtimes are linked in is actually a little subtle in that they're
80 // "sort of" in the compiler's crate store, but only actually linked if another
81 // isn't actually linked. This ends up meaning that both this crate and the
82 // panic_unwind crate can appear in the compiler's crate store, and if both
83 // define the `eh_personality` lang item then that'll hit an error.
85 // To handle this the compiler only requires the `eh_personality` is defined if
86 // the panic runtime being linked in is the unwinding runtime, and otherwise
87 // it's not required to be defined (rightfully so). In this case, however, this
88 // library just defines this symbol so there's at least some personality
91 // Essentially this symbol is just defined to get wired up to libcore/libstd
92 // binaries, but it should never be called as we don't link in an unwinding
94 pub mod personalities {
97 all(target_arch = "wasm32", not(target_os = "emscripten"),),
98 all(target_os = "windows", target_env = "gnu", target_arch = "x86_64",),
100 pub extern "C" fn rust_eh_personality() {}
102 // On x86_64-pc-windows-gnu we use our own personality function that needs
103 // to return `ExceptionContinueSearch` as we're passing on all our frames.
105 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86_64"))]
106 pub extern "C" fn rust_eh_personality(
112 1 // `ExceptionContinueSearch`
115 // Similar to above, this corresponds to the `eh_unwind_resume` lang item
116 // that's only used on Windows currently.
118 // Note that we don't execute landing pads, so this is never called, so it's
121 #[cfg(all(target_os = "windows", target_env = "gnu"))]
122 pub extern "C" fn rust_eh_unwind_resume() {}
124 // These two are called by our startup objects on i686-pc-windows-gnu, but
125 // they don't need to do anything so the bodies are nops.
127 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
128 pub extern "C" fn rust_eh_register_frames() {}
130 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
131 pub extern "C" fn rust_eh_unregister_frames() {}