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1 | // Copyright 2016 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | //! Implementation of Rust panics via process aborts | |
12 | //! | |
13 | //! When compared to the implementation via unwinding, this crate is *much* | |
14 | //! simpler! That being said, it's not quite as versatile, but here goes! | |
15 | ||
16 | #![no_std] | |
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17 | #![unstable(feature = "panic_abort", issue = "32837")] |
18 | #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png", | |
19 | html_favicon_url = "https://doc.rust-lang.org/favicon.ico", | |
20 | html_root_url = "https://doc.rust-lang.org/nightly/", | |
21 | issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")] | |
32a655c1 | 22 | #![deny(warnings)] |
3157f602 | 23 | #![panic_runtime] |
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24 | #![allow(unused_features)] |
25 | ||
26 | #![feature(core_intrinsics)] | |
27 | #![feature(libc)] | |
3157f602 | 28 | #![feature(panic_runtime)] |
abe05a73 | 29 | #![feature(staged_api)] |
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30 | |
31 | // Rust's "try" function, but if we're aborting on panics we just call the | |
32 | // function as there's nothing else we need to do here. | |
33 | #[no_mangle] | |
34 | pub unsafe extern fn __rust_maybe_catch_panic(f: fn(*mut u8), | |
35 | data: *mut u8, | |
36 | _data_ptr: *mut usize, | |
37 | _vtable_ptr: *mut usize) -> u32 { | |
38 | f(data); | |
39 | 0 | |
40 | } | |
41 | ||
42 | // "Leak" the payload and shim to the relevant abort on the platform in | |
43 | // question. | |
44 | // | |
45 | // For Unix we just use `abort` from libc as it'll trigger debuggers, core | |
46 | // dumps, etc, as one might expect. On Windows, however, the best option we have | |
47 | // is the `__fastfail` intrinsics, but that's unfortunately not defined in LLVM, | |
48 | // and the `RaiseFailFastException` function isn't available until Windows 7 | |
49 | // which would break compat with XP. For now just use `intrinsics::abort` which | |
50 | // will kill us with an illegal instruction, which will do a good enough job for | |
51 | // now hopefully. | |
52 | #[no_mangle] | |
53 | pub unsafe extern fn __rust_start_panic(_data: usize, _vtable: usize) -> u32 { | |
476ff2be | 54 | abort(); |
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55 | |
56 | #[cfg(unix)] | |
57 | unsafe fn abort() -> ! { | |
58 | extern crate libc; | |
59 | libc::abort(); | |
60 | } | |
61 | ||
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62 | #[cfg(any(target_os = "redox", |
63 | windows, | |
64 | all(target_arch = "wasm32", not(target_os = "emscripten"))))] | |
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65 | unsafe fn abort() -> ! { |
66 | core::intrinsics::abort(); | |
67 | } | |
68 | } | |
69 | ||
70 | // This... is a bit of an oddity. The tl;dr; is that this is required to link | |
71 | // correctly, the longer explanation is below. | |
72 | // | |
73 | // Right now the binaries of libcore/libstd that we ship are all compiled with | |
74 | // `-C panic=unwind`. This is done to ensure that the binaries are maximally | |
75 | // compatible with as many situations as possible. The compiler, however, | |
76 | // requires a "personality function" for all functions compiled with `-C | |
77 | // panic=unwind`. This personality function is hardcoded to the symbol | |
78 | // `rust_eh_personality` and is defined by the `eh_personality` lang item. | |
79 | // | |
80 | // So... why not just define that lang item here? Good question! The way that | |
81 | // panic runtimes are linked in is actually a little subtle in that they're | |
82 | // "sort of" in the compiler's crate store, but only actually linked if another | |
83 | // isn't actually linked. This ends up meaning that both this crate and the | |
84 | // panic_unwind crate can appear in the compiler's crate store, and if both | |
85 | // define the `eh_personality` lang item then that'll hit an error. | |
86 | // | |
87 | // To handle this the compiler only requires the `eh_personality` is defined if | |
88 | // the panic runtime being linked in is the unwinding runtime, and otherwise | |
89 | // it's not required to be defined (rightfully so). In this case, however, this | |
90 | // library just defines this symbol so there's at least some personality | |
91 | // somewhere. | |
92 | // | |
93 | // Essentially this symbol is just defined to get wired up to libcore/libstd | |
94 | // binaries, but it should never be called as we don't link in an unwinding | |
95 | // runtime at all. | |
a7813a04 | 96 | pub mod personalities { |
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97 | #[no_mangle] |
98 | #[cfg(not(all(target_os = "windows", | |
99 | target_env = "gnu", | |
100 | target_arch = "x86_64")))] | |
101 | pub extern fn rust_eh_personality() {} | |
102 | ||
103 | // On x86_64-pc-windows-gnu we use our own personality function that needs | |
104 | // to return `ExceptionContinueSearch` as we're passing on all our frames. | |
105 | #[no_mangle] | |
106 | #[cfg(all(target_os = "windows", | |
107 | target_env = "gnu", | |
108 | target_arch = "x86_64"))] | |
109 | pub extern fn rust_eh_personality(_record: usize, | |
110 | _frame: usize, | |
111 | _context: usize, | |
112 | _dispatcher: usize) -> u32 { | |
113 | 1 // `ExceptionContinueSearch` | |
114 | } | |
115 | ||
116 | // Similar to above, this corresponds to the `eh_unwind_resume` lang item | |
117 | // that's only used on Windows currently. | |
118 | // | |
119 | // Note that we don't execute landing pads, so this is never called, so it's | |
120 | // body is empty. | |
121 | #[no_mangle] | |
122 | #[cfg(all(target_os = "windows", target_env = "gnu"))] | |
123 | pub extern fn rust_eh_unwind_resume() {} | |
124 | ||
125 | // These two are called by our startup objects on i686-pc-windows-gnu, but | |
126 | // they don't need to do anything so the bodies are nops. | |
127 | #[no_mangle] | |
128 | #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))] | |
129 | pub extern fn rust_eh_register_frames() {} | |
130 | #[no_mangle] | |
131 | #[cfg(all(target_os = "windows", target_env = "gnu", target_arch = "x86"))] | |
132 | pub extern fn rust_eh_unregister_frames() {} | |
133 | } |