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