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(all(windows, any(target_arch = "x86", target_arch = "x86_64")))] {
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 llvm_asm!("int $$0x29" :: "{ecx}"(7) ::: volatile); // 7 is FAST_FAIL_FATAL_APP_EXIT
63 core::intrinsics::unreachable();
66 unsafe fn abort() -> ! {
67 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 {
100 #[rustc_std_internal_symbol]
102 all(target_arch = "wasm32", not(target_os = "emscripten"),),
103 all(target_os = "windows", target_env = "gnu", target_arch = "x86_64",),
105 pub extern "C" fn rust_eh_personality() {}
107 // On x86_64-pc-windows-gnu we use our own personality function that needs
108 // to return `ExceptionContinueSearch` as we're passing on all our frames.
109 #[rustc_std_internal_symbol]
110 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86_64"))]
111 pub extern "C" fn rust_eh_personality(
117 1 // `ExceptionContinueSearch`
120 // These two are called by our startup objects on i686-pc-windows-gnu, but
121 // they don't need to do anything so the bodies are nops.
122 #[rustc_std_internal_symbol]
123 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
124 pub extern "C" fn rust_eh_register_frames() {}
125 #[rustc_std_internal_symbol]
126 #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))]
127 pub extern "C" fn rust_eh_unregister_frames() {}