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)]
16 #![feature(panic_runtime)]
17 #![feature(std_internals)]
18 #![feature(staged_api)]
19 #![feature(rustc_attrs)]
22 #[cfg(target_os = "android")]
26 use core::panic::BoxMeUp;
28 #[rustc_std_internal_symbol]
29 #[allow(improper_ctypes_definitions)]
30 pub unsafe extern "C" fn __rust_panic_cleanup(_: *mut u8) -> *mut (dyn Any + Send + 'static) {
34 // "Leak" the payload and shim to the relevant abort on the platform in question.
35 #[rustc_std_internal_symbol]
36 pub unsafe extern "C" fn __rust_start_panic(_payload: *mut &mut dyn BoxMeUp) -> u32 {
37 // Android has the ability to attach a message as part of the abort.
38 #[cfg(target_os = "android")]
39 android::android_set_abort_message(_payload);
45 unsafe fn abort() -> ! {
48 } else if #[cfg(any(target_os = "hermit",
49 all(target_vendor = "fortanix", target_env = "sgx")
51 unsafe fn abort() -> ! {
52 // call std::sys::abort_internal
54 pub fn __rust_abort() -> !;
58 } else if #[cfg(all(windows, not(miri)))] {
59 // On Windows, use the processor-specific __fastfail mechanism. In Windows 8
60 // and later, this will terminate the process immediately without running any
61 // in-process exception handlers. In earlier versions of Windows, this
62 // sequence of instructions will be treated as an access violation,
63 // terminating the process but without necessarily bypassing all exception
66 // https://docs.microsoft.com/en-us/cpp/intrinsics/fastfail
68 // Note: this is the same implementation as in libstd's `abort_internal`
69 unsafe fn abort() -> ! {
70 const FAST_FAIL_FATAL_APP_EXIT: usize = 7;
72 if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
73 asm!("int $$0x29", in("ecx") FAST_FAIL_FATAL_APP_EXIT);
74 } else if #[cfg(all(target_arch = "arm", target_feature = "thumb-mode"))] {
75 asm!(".inst 0xDEFB", in("r0") FAST_FAIL_FATAL_APP_EXIT);
76 } else if #[cfg(target_arch = "aarch64")] {
77 asm!("brk 0xF003", in("x0") FAST_FAIL_FATAL_APP_EXIT);
79 core::intrinsics::abort();
82 core::intrinsics::unreachable();
85 unsafe fn abort() -> ! {
86 core::intrinsics::abort();
92 // This... is a bit of an oddity. The tl;dr; is that this is required to link
93 // correctly, the longer explanation is below.
95 // Right now the binaries of libcore/libstd that we ship are all compiled with
96 // `-C panic=unwind`. This is done to ensure that the binaries are maximally
97 // compatible with as many situations as possible. The compiler, however,
98 // requires a "personality function" for all functions compiled with `-C
99 // panic=unwind`. This personality function is hardcoded to the symbol
100 // `rust_eh_personality` and is defined by the `eh_personality` lang item.
102 // So... why not just define that lang item here? Good question! The way that
103 // panic runtimes are linked in is actually a little subtle in that they're
104 // "sort of" in the compiler's crate store, but only actually linked if another
105 // isn't actually linked. This ends up meaning that both this crate and the
106 // panic_unwind crate can appear in the compiler's crate store, and if both
107 // define the `eh_personality` lang item then that'll hit an error.
109 // To handle this the compiler only requires the `eh_personality` is defined if
110 // the panic runtime being linked in is the unwinding runtime, and otherwise
111 // it's not required to be defined (rightfully so). In this case, however, this
112 // library just defines this symbol so there's at least some personality
115 // Essentially this symbol is just defined to get wired up to libcore/libstd
116 // binaries, but it should never be called as we don't link in an unwinding
118 pub mod personalities {
119 #[rustc_std_internal_symbol]
121 all(target_arch = "wasm32", not(target_os = "emscripten"),),
122 all(target_os = "windows", target_env = "gnu", target_arch = "x86_64",),
124 pub extern "C" fn rust_eh_personality() {}
126 // On x86_64-pc-windows-gnu we use our own personality function that needs
127 // to return `ExceptionContinueSearch` as we're passing on all our frames.
128 #[rustc_std_internal_symbol]
129 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86_64"))]
130 pub extern "C" fn rust_eh_personality(
136 1 // `ExceptionContinueSearch`
139 // Similar to above, this corresponds to the `eh_catch_typeinfo` lang item
140 // that's only used on Emscripten currently.
142 // Since panics don't generate exceptions and foreign exceptions are
143 // currently UB with -C panic=abort (although this may be subject to
144 // change), any catch_unwind calls will never use this typeinfo.
145 #[rustc_std_internal_symbol]
146 #[allow(non_upper_case_globals)]
147 #[cfg(target_os = "emscripten")]
148 static rust_eh_catch_typeinfo: [usize; 2] = [0; 2];
150 // These two are called by our startup objects on i686-pc-windows-gnu, but
151 // they don't need to do anything so the bodies are nops.
152 #[rustc_std_internal_symbol]
153 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
154 pub extern "C" fn rust_eh_register_frames() {}
155 #[rustc_std_internal_symbol]
156 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
157 pub extern "C" fn rust_eh_unregister_frames() {}