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)]
24 #[rustc_std_internal_symbol]
25 #[allow(improper_ctypes_definitions)]
26 pub unsafe extern "C" fn __rust_panic_cleanup(_: *mut u8) -> *mut (dyn Any + Send + 'static) {
30 // "Leak" the payload and shim to the relevant abort on the platform in question.
31 #[rustc_std_internal_symbol]
32 pub unsafe extern "C" fn __rust_start_panic(_payload: usize) -> u32 {
36 if #[cfg(any(unix, target_os = "cloudabi"))] {
37 unsafe fn abort() -> ! {
40 } else if #[cfg(any(target_os = "hermit",
41 all(target_vendor = "fortanix", target_env = "sgx")
43 unsafe fn abort() -> ! {
44 // call std::sys::abort_internal
46 pub fn __rust_abort() -> !;
50 } else if #[cfg(windows)] {
51 // On Windows, use the processor-specific __fastfail mechanism. In Windows 8
52 // and later, this will terminate the process immediately without running any
53 // in-process exception handlers. In earlier versions of Windows, this
54 // sequence of instructions will be treated as an access violation,
55 // terminating the process but without necessarily bypassing all exception
58 // https://docs.microsoft.com/en-us/cpp/intrinsics/fastfail
60 // Note: this is the same implementation as in libstd's `abort_internal`
61 unsafe fn abort() -> ! {
62 const FAST_FAIL_FATAL_APP_EXIT: usize = 7;
64 if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
65 asm!("int $$0x29", in("ecx") FAST_FAIL_FATAL_APP_EXIT);
66 } else if #[cfg(target_arch = "arm")] {
67 asm!(".inst 0xDEFB", in("r0") FAST_FAIL_FATAL_APP_EXIT);
68 } else if #[cfg(target_arch = "aarch64")] {
69 asm!("brk 0xF003", in("x0") FAST_FAIL_FATAL_APP_EXIT);
71 core::intrinsics::abort();
74 core::intrinsics::unreachable();
77 unsafe fn abort() -> ! {
78 core::intrinsics::abort();
84 // This... is a bit of an oddity. The tl;dr; is that this is required to link
85 // correctly, the longer explanation is below.
87 // Right now the binaries of libcore/libstd that we ship are all compiled with
88 // `-C panic=unwind`. This is done to ensure that the binaries are maximally
89 // compatible with as many situations as possible. The compiler, however,
90 // requires a "personality function" for all functions compiled with `-C
91 // panic=unwind`. This personality function is hardcoded to the symbol
92 // `rust_eh_personality` and is defined by the `eh_personality` lang item.
94 // So... why not just define that lang item here? Good question! The way that
95 // panic runtimes are linked in is actually a little subtle in that they're
96 // "sort of" in the compiler's crate store, but only actually linked if another
97 // isn't actually linked. This ends up meaning that both this crate and the
98 // panic_unwind crate can appear in the compiler's crate store, and if both
99 // define the `eh_personality` lang item then that'll hit an error.
101 // To handle this the compiler only requires the `eh_personality` is defined if
102 // the panic runtime being linked in is the unwinding runtime, and otherwise
103 // it's not required to be defined (rightfully so). In this case, however, this
104 // library just defines this symbol so there's at least some personality
107 // Essentially this symbol is just defined to get wired up to libcore/libstd
108 // binaries, but it should never be called as we don't link in an unwinding
110 pub mod personalities {
111 #[rustc_std_internal_symbol]
113 all(target_arch = "wasm32", not(target_os = "emscripten"),),
114 all(target_os = "windows", target_env = "gnu", target_arch = "x86_64",),
116 pub extern "C" fn rust_eh_personality() {}
118 // On x86_64-pc-windows-gnu we use our own personality function that needs
119 // to return `ExceptionContinueSearch` as we're passing on all our frames.
120 #[rustc_std_internal_symbol]
121 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86_64"))]
122 pub extern "C" fn rust_eh_personality(
128 1 // `ExceptionContinueSearch`
131 // These two are called by our startup objects on i686-pc-windows-gnu, but
132 // they don't need to do anything so the bodies are nops.
133 #[rustc_std_internal_symbol]
134 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
135 pub extern "C" fn rust_eh_register_frames() {}
136 #[rustc_std_internal_symbol]
137 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
138 pub extern "C" fn rust_eh_unregister_frames() {}