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</pre><pre class="rust ">
<span class="comment">// Copyright 2014 The Rust Project Developers. See the COPYRIGHT</span>
<span class="comment">// file at the top-level directory of this distribution and at</span>
<span class="comment">// http://rust-lang.org/COPYRIGHT.</span>
<span class="comment">//</span>
<span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span>
<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span>
<span class="comment">// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your</span>
<span class="comment">// option. This file may not be copied, modified, or distributed</span>
<span class="comment">// except according to those terms.</span>
<span class="doccomment">//! Implementation of various bits and pieces of the `panic!` macro and</span>
<span class="doccomment">//! associated runtime pieces.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! Specifically, this module contains the implementation of:</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! * Panic hooks</span>
<span class="doccomment">//! * Executing a panic up to doing the actual implementation</span>
<span class="doccomment">//! * Shims around "try"</span>
<span class="kw">use</span> <span class="ident">io</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="ident">any</span>::<span class="ident">Any</span>;
<span class="kw">use</span> <span class="ident">cell</span>::<span class="ident">RefCell</span>;
<span class="kw">use</span> <span class="ident">fmt</span>;
<span class="kw">use</span> <span class="ident">intrinsics</span>;
<span class="kw">use</span> <span class="ident">mem</span>;
<span class="kw">use</span> <span class="ident">ptr</span>;
<span class="kw">use</span> <span class="ident">raw</span>;
<span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">stdio</span>::<span class="ident">Stderr</span>;
<span class="kw">use</span> <span class="ident">sys_common</span>::<span class="ident">rwlock</span>::<span class="ident">RWLock</span>;
<span class="kw">use</span> <span class="ident">sys_common</span>::<span class="ident">thread_info</span>;
<span class="kw">use</span> <span class="ident">sys_common</span>::<span class="ident">util</span>;
<span class="kw">use</span> <span class="ident">thread</span>;
<span class="macro">thread_local</span><span class="macro">!</span> {
<span class="kw">pub</span> <span class="kw">static</span> <span class="ident">LOCAL_STDERR</span>: <span class="ident">RefCell</span><span class="op"><</span><span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">Box</span><span class="op"><</span><span class="ident">Write</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">>></span><span class="op">></span> <span class="op">=</span> {
<span class="ident">RefCell</span>::<span class="ident">new</span>(<span class="prelude-val">None</span>)
}
}
<span class="comment">// Binary interface to the panic runtime that the standard library depends on.</span>
<span class="comment">//</span>
<span class="comment">// The standard library is tagged with `#![needs_panic_runtime]` (introduced in</span>
<span class="comment">// RFC 1513) to indicate that it requires some other crate tagged with</span>
<span class="comment">// `#![panic_runtime]` to exist somewhere. Each panic runtime is intended to</span>
<span class="comment">// implement these symbols (with the same signatures) so we can get matched up</span>
<span class="comment">// to them.</span>
<span class="comment">//</span>
<span class="comment">// One day this may look a little less ad-hoc with the compiler helping out to</span>
<span class="comment">// hook up these functions, but it is not this day!</span>
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">improper_ctypes</span>)]</span>
<span class="kw">extern</span> {
<span class="kw">fn</span> <span class="ident">__rust_maybe_catch_panic</span>(<span class="ident">f</span>: <span class="kw">fn</span>(<span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">u8</span>),
<span class="ident">data</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">u8</span>,
<span class="ident">data_ptr</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">usize</span>,
<span class="ident">vtable_ptr</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">u32</span>;
<span class="attribute">#[<span class="ident">unwind</span>]</span>
<span class="kw">fn</span> <span class="ident">__rust_start_panic</span>(<span class="ident">data</span>: <span class="ident">usize</span>, <span class="ident">vtable</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">u32</span>;
}
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Copy</span>, <span class="ident">Clone</span>)]</span>
<span class="kw">enum</span> <span class="ident">Hook</span> {
<span class="ident">Default</span>,
<span class="ident">Custom</span>(<span class="kw-2">*</span><span class="kw-2">mut</span> (<span class="ident">Fn</span>(<span class="kw-2">&</span><span class="ident">PanicInfo</span>) <span class="op">+</span> <span class="lifetime">'static</span> <span class="op">+</span> <span class="ident">Sync</span> <span class="op">+</span> <span class="ident">Send</span>)),
}
<span class="kw">static</span> <span class="ident">HOOK_LOCK</span>: <span class="ident">RWLock</span> <span class="op">=</span> <span class="ident">RWLock</span>::<span class="ident">new</span>();
<span class="kw">static</span> <span class="kw-2">mut</span> <span class="ident">HOOK</span>: <span class="ident">Hook</span> <span class="op">=</span> <span class="ident">Hook</span>::<span class="ident">Default</span>;
<span class="doccomment">/// Registers a custom panic hook, replacing any that was previously registered.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The panic hook is invoked when a thread panics, but before the panic runtime</span>
<span class="doccomment">/// is invoked. As such, the hook will run with both the aborting and unwinding</span>
<span class="doccomment">/// runtimes. The default hook prints a message to standard error and generates</span>
<span class="doccomment">/// a backtrace if requested, but this behavior can be customized with the</span>
<span class="doccomment">/// `set_hook` and `take_hook` functions.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The hook is provided with a `PanicInfo` struct which contains information</span>
<span class="doccomment">/// about the origin of the panic, including the payload passed to `panic!` and</span>
<span class="doccomment">/// the source code location from which the panic originated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The panic hook is a global resource.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Panics if called from a panicking thread.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The following will print "Custom panic hook":</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|_| {</span>
<span class="doccomment">/// println!("Custom panic hook");</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">set_hook</span>(<span class="ident">hook</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">Fn</span>(<span class="kw-2">&</span><span class="ident">PanicInfo</span>) <span class="op">+</span> <span class="lifetime">'static</span> <span class="op">+</span> <span class="ident">Sync</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span>) {
<span class="kw">if</span> <span class="ident">thread</span>::<span class="ident">panicking</span>() {
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">"cannot modify the panic hook from a panicking thread"</span>);
}
<span class="kw">unsafe</span> {
<span class="ident">HOOK_LOCK</span>.<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">old_hook</span> <span class="op">=</span> <span class="ident">HOOK</span>;
<span class="ident">HOOK</span> <span class="op">=</span> <span class="ident">Hook</span>::<span class="ident">Custom</span>(<span class="ident">Box</span>::<span class="ident">into_raw</span>(<span class="ident">hook</span>));
<span class="ident">HOOK_LOCK</span>.<span class="ident">write_unlock</span>();
<span class="kw">if</span> <span class="kw">let</span> <span class="ident">Hook</span>::<span class="ident">Custom</span>(<span class="ident">ptr</span>) <span class="op">=</span> <span class="ident">old_hook</span> {
<span class="ident">Box</span>::<span class="ident">from_raw</span>(<span class="ident">ptr</span>);
}
}
}
<span class="doccomment">/// Unregisters the current panic hook, returning it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If no custom hook is registered, the default hook will be returned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Panics if called from a panicking thread.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The following will print "Normal panic":</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|_| {</span>
<span class="doccomment">/// println!("Custom panic hook");</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let _ = panic::take_hook();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">take_hook</span>() <span class="op">-></span> <span class="ident">Box</span><span class="op"><</span><span class="ident">Fn</span>(<span class="kw-2">&</span><span class="ident">PanicInfo</span>) <span class="op">+</span> <span class="lifetime">'static</span> <span class="op">+</span> <span class="ident">Sync</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">thread</span>::<span class="ident">panicking</span>() {
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">"cannot modify the panic hook from a panicking thread"</span>);
}
<span class="kw">unsafe</span> {
<span class="ident">HOOK_LOCK</span>.<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">hook</span> <span class="op">=</span> <span class="ident">HOOK</span>;
<span class="ident">HOOK</span> <span class="op">=</span> <span class="ident">Hook</span>::<span class="ident">Default</span>;
<span class="ident">HOOK_LOCK</span>.<span class="ident">write_unlock</span>();
<span class="kw">match</span> <span class="ident">hook</span> {
<span class="ident">Hook</span>::<span class="ident">Default</span> <span class="op">=></span> <span class="ident">Box</span>::<span class="ident">new</span>(<span class="ident">default_hook</span>),
<span class="ident">Hook</span>::<span class="ident">Custom</span>(<span class="ident">ptr</span>) <span class="op">=></span> <span class="ident">Box</span>::<span class="ident">from_raw</span>(<span class="ident">ptr</span>),
}
}
}
<span class="doccomment">/// A struct providing information about a panic.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `PanicInfo` structure is passed to a panic hook set by the [`set_hook`]</span>
<span class="doccomment">/// function.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`set_hook`]: ../../std/panic/fn.set_hook.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// println!("panic occurred: {:?}", panic_info.payload().downcast_ref::<&str>().unwrap());</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">PanicInfo</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {
<span class="ident">payload</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> (<span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span>),
<span class="ident">location</span>: <span class="ident">Location</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">PanicInfo</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {
<span class="doccomment">/// Returns the payload associated with the panic.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This will commonly, but not always, be a `&'static str` or [`String`].</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`String`]: ../../std/string/struct.String.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// println!("panic occurred: {:?}", panic_info.payload().downcast_ref::<&str>().unwrap());</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">payload</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span>(<span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span>) {
<span class="self">self</span>.<span class="ident">payload</span>
}
<span class="doccomment">/// Returns information about the location from which the panic originated,</span>
<span class="doccomment">/// if available.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method will currently always return [`Some`], but this may change</span>
<span class="doccomment">/// in future versions.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`Some`]: ../../std/option/enum.Option.html#variant.Some</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// if let Some(location) = panic_info.location() {</span>
<span class="doccomment">/// println!("panic occurred in file '{}' at line {}", location.file(),</span>
<span class="doccomment">/// location.line());</span>
<span class="doccomment">/// } else {</span>
<span class="doccomment">/// println!("panic occurred but can't get location information...");</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">location</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Location</span><span class="op">></span> {
<span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">location</span>)
}
}
<span class="doccomment">/// A struct containing information about the location of a panic.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This structure is created by the [`location`] method of [`PanicInfo`].</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`location`]: ../../std/panic/struct.PanicInfo.html#method.location</span>
<span class="doccomment">/// [`PanicInfo`]: ../../std/panic/struct.PanicInfo.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// if let Some(location) = panic_info.location() {</span>
<span class="doccomment">/// println!("panic occurred in file '{}' at line {}", location.file(), location.line());</span>
<span class="doccomment">/// } else {</span>
<span class="doccomment">/// println!("panic occurred but can't get location information...");</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Location</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {
<span class="ident">file</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>,
<span class="ident">line</span>: <span class="ident">u32</span>,
<span class="ident">col</span>: <span class="ident">u32</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">Location</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {
<span class="doccomment">/// Returns the name of the source file from which the panic originated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// if let Some(location) = panic_info.location() {</span>
<span class="doccomment">/// println!("panic occurred in file '{}'", location.file());</span>
<span class="doccomment">/// } else {</span>
<span class="doccomment">/// println!("panic occurred but can't get location information...");</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">file</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">str</span> {
<span class="self">self</span>.<span class="ident">file</span>
}
<span class="doccomment">/// Returns the line number from which the panic originated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// if let Some(location) = panic_info.location() {</span>
<span class="doccomment">/// println!("panic occurred at line {}", location.line());</span>
<span class="doccomment">/// } else {</span>
<span class="doccomment">/// println!("panic occurred but can't get location information...");</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_hooks"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.10.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">line</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">u32</span> {
<span class="self">self</span>.<span class="ident">line</span>
}
<span class="doccomment">/// Returns the column from which the panic originated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```should_panic</span>
<span class="doccomment">/// use std::panic;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic::set_hook(Box::new(|panic_info| {</span>
<span class="doccomment">/// if let Some(location) = panic_info.location() {</span>
<span class="doccomment">/// println!("panic occurred at column {}", location.column());</span>
<span class="doccomment">/// } else {</span>
<span class="doccomment">/// println!("panic occurred but can't get location information...");</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// }));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// panic!("Normal panic");</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"panic_col"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.25"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">column</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">u32</span> {
<span class="self">self</span>.<span class="ident">col</span>
}
}
<span class="kw">fn</span> <span class="ident">default_hook</span>(<span class="ident">info</span>: <span class="kw-2">&</span><span class="ident">PanicInfo</span>) {
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"backtrace"</span>)]</span>
<span class="kw">use</span> <span class="ident">sys_common</span>::<span class="ident">backtrace</span>;
<span class="comment">// If this is a double panic, make sure that we print a backtrace</span>
<span class="comment">// for this panic. Otherwise only print it if logging is enabled.</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"backtrace"</span>)]</span>
<span class="kw">let</span> <span class="ident">log_backtrace</span> <span class="op">=</span> {
<span class="kw">let</span> <span class="ident">panics</span> <span class="op">=</span> <span class="ident">update_panic_count</span>(<span class="number">0</span>);
<span class="kw">if</span> <span class="ident">panics</span> <span class="op">>=</span> <span class="number">2</span> {
<span class="prelude-val">Some</span>(<span class="ident">backtrace</span>::<span class="ident">PrintFormat</span>::<span class="ident">Full</span>)
} <span class="kw">else</span> {
<span class="ident">backtrace</span>::<span class="ident">log_enabled</span>()
}
};
<span class="kw">let</span> <span class="ident">file</span> <span class="op">=</span> <span class="ident">info</span>.<span class="ident">location</span>.<span class="ident">file</span>;
<span class="kw">let</span> <span class="ident">line</span> <span class="op">=</span> <span class="ident">info</span>.<span class="ident">location</span>.<span class="ident">line</span>;
<span class="kw">let</span> <span class="ident">col</span> <span class="op">=</span> <span class="ident">info</span>.<span class="ident">location</span>.<span class="ident">col</span>;
<span class="kw">let</span> <span class="ident">msg</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">info</span>.<span class="ident">payload</span>.<span class="ident">downcast_ref</span>::<span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span><span class="op">></span>() {
<span class="prelude-val">Some</span>(<span class="ident">s</span>) <span class="op">=></span> <span class="kw-2">*</span><span class="ident">s</span>,
<span class="prelude-val">None</span> <span class="op">=></span> <span class="kw">match</span> <span class="ident">info</span>.<span class="ident">payload</span>.<span class="ident">downcast_ref</span>::<span class="op"><</span><span class="ident">String</span><span class="op">></span>() {
<span class="prelude-val">Some</span>(<span class="ident">s</span>) <span class="op">=></span> <span class="kw-2">&</span><span class="ident">s</span>[..],
<span class="prelude-val">None</span> <span class="op">=></span> <span class="string">"Box<Any>"</span>,
}
};
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">err</span> <span class="op">=</span> <span class="ident">Stderr</span>::<span class="ident">new</span>().<span class="ident">ok</span>();
<span class="kw">let</span> <span class="ident">thread</span> <span class="op">=</span> <span class="ident">thread_info</span>::<span class="ident">current_thread</span>();
<span class="kw">let</span> <span class="ident">name</span> <span class="op">=</span> <span class="ident">thread</span>.<span class="ident">as_ref</span>().<span class="ident">and_then</span>(<span class="op">|</span><span class="ident">t</span><span class="op">|</span> <span class="ident">t</span>.<span class="ident">name</span>()).<span class="ident">unwrap_or</span>(<span class="string">"<unnamed>"</span>);
<span class="kw">let</span> <span class="ident">write</span> <span class="op">=</span> <span class="op">|</span><span class="ident">err</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> ::<span class="ident">io</span>::<span class="ident">Write</span><span class="op">|</span> {
<span class="kw">let</span> _ <span class="op">=</span> <span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">err</span>, <span class="string">"thread '{}' panicked at '{}', {}:{}:{}"</span>,
<span class="ident">name</span>, <span class="ident">msg</span>, <span class="ident">file</span>, <span class="ident">line</span>, <span class="ident">col</span>);
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"backtrace"</span>)]</span>
{
<span class="kw">use</span> <span class="ident">sync</span>::<span class="ident">atomic</span>::{<span class="ident">AtomicBool</span>, <span class="ident">Ordering</span>};
<span class="kw">static</span> <span class="ident">FIRST_PANIC</span>: <span class="ident">AtomicBool</span> <span class="op">=</span> <span class="ident">AtomicBool</span>::<span class="ident">new</span>(<span class="bool-val">true</span>);
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">format</span>) <span class="op">=</span> <span class="ident">log_backtrace</span> {
<span class="kw">let</span> _ <span class="op">=</span> <span class="ident">backtrace</span>::<span class="ident">print</span>(<span class="ident">err</span>, <span class="ident">format</span>);
} <span class="kw">else</span> <span class="kw">if</span> <span class="ident">FIRST_PANIC</span>.<span class="ident">compare_and_swap</span>(<span class="bool-val">true</span>, <span class="bool-val">false</span>, <span class="ident">Ordering</span>::<span class="ident">SeqCst</span>) {
<span class="kw">let</span> _ <span class="op">=</span> <span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">err</span>, <span class="string">"note: Run with `RUST_BACKTRACE=1` for a backtrace."</span>);
}
}
};
<span class="kw">let</span> <span class="ident">prev</span> <span class="op">=</span> <span class="ident">LOCAL_STDERR</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">borrow_mut</span>().<span class="ident">take</span>());
<span class="kw">match</span> (<span class="ident">prev</span>, <span class="ident">err</span>.<span class="ident">as_mut</span>()) {
(<span class="prelude-val">Some</span>(<span class="kw-2">mut</span> <span class="ident">stderr</span>), _) <span class="op">=></span> {
<span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span><span class="ident">stderr</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="prelude-val">Some</span>(<span class="ident">stderr</span>);
<span class="ident">LOCAL_STDERR</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">slot</span><span class="op">|</span> {
<span class="kw-2">*</span><span class="ident">slot</span>.<span class="ident">borrow_mut</span>() <span class="op">=</span> <span class="ident">s</span>.<span class="ident">take</span>();
});
}
(<span class="prelude-val">None</span>, <span class="prelude-val">Some</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">err</span>)) <span class="op">=></span> { <span class="ident">write</span>(<span class="ident">err</span>) }
_ <span class="op">=></span> {}
}
}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">test</span>))]</span>
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"update_panic_count"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">update_panic_count</span>(<span class="ident">amt</span>: <span class="ident">isize</span>) <span class="op">-></span> <span class="ident">usize</span> {
<span class="kw">use</span> <span class="ident">cell</span>::<span class="ident">Cell</span>;
<span class="macro">thread_local</span><span class="macro">!</span> { <span class="kw">static</span> <span class="ident">PANIC_COUNT</span>: <span class="ident">Cell</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> <span class="op">=</span> <span class="ident">Cell</span>::<span class="ident">new</span>(<span class="number">0</span>) }
<span class="ident">PANIC_COUNT</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> {
<span class="kw">let</span> <span class="ident">next</span> <span class="op">=</span> (<span class="ident">c</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="ident">isize</span> <span class="op">+</span> <span class="ident">amt</span>) <span class="kw">as</span> <span class="ident">usize</span>;
<span class="ident">c</span>.<span class="ident">set</span>(<span class="ident">next</span>);
<span class="kw">return</span> <span class="ident">next</span>
})
}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">pub</span> <span class="kw">use</span> <span class="ident">realstd</span>::<span class="ident">rt</span>::<span class="ident">update_panic_count</span>;
<span class="doccomment">/// Invoke a closure, capturing the cause of an unwinding panic if one occurs.</span>
<span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">try</span><span class="op"><</span><span class="ident">R</span>, <span class="ident">F</span>: <span class="ident">FnOnce</span>() <span class="op">-></span> <span class="ident">R</span><span class="op">></span>(<span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">R</span>, <span class="ident">Box</span><span class="op"><</span><span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">>></span> {
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">unions_with_drop_fields</span>)]</span>
<span class="ident">union</span> <span class="ident">Data</span><span class="op"><</span><span class="ident">F</span>, <span class="ident">R</span><span class="op">></span> {
<span class="ident">f</span>: <span class="ident">F</span>,
<span class="ident">r</span>: <span class="ident">R</span>,
}
<span class="comment">// We do some sketchy operations with ownership here for the sake of</span>
<span class="comment">// performance. We can only pass pointers down to</span>
<span class="comment">// `__rust_maybe_catch_panic` (can't pass objects by value), so we do all</span>
<span class="comment">// the ownership tracking here manually using a union.</span>
<span class="comment">//</span>
<span class="comment">// We go through a transition where:</span>
<span class="comment">//</span>
<span class="comment">// * First, we set the data to be the closure that we're going to call.</span>
<span class="comment">// * When we make the function call, the `do_call` function below, we take</span>
<span class="comment">// ownership of the function pointer. At this point the `Data` union is</span>
<span class="comment">// entirely uninitialized.</span>
<span class="comment">// * If the closure successfully returns, we write the return value into the</span>
<span class="comment">// data's return slot. Note that `ptr::write` is used as it's overwriting</span>
<span class="comment">// uninitialized data.</span>
<span class="comment">// * Finally, when we come back out of the `__rust_maybe_catch_panic` we're</span>
<span class="comment">// in one of two states:</span>
<span class="comment">//</span>
<span class="comment">// 1. The closure didn't panic, in which case the return value was</span>
<span class="comment">// filled in. We move it out of `data` and return it.</span>
<span class="comment">// 2. The closure panicked, in which case the return value wasn't</span>
<span class="comment">// filled in. In this case the entire `data` union is invalid, so</span>
<span class="comment">// there is no need to drop anything.</span>
<span class="comment">//</span>
<span class="comment">// Once we stack all that together we should have the "most efficient'</span>
<span class="comment">// method of calling a catch panic whilst juggling ownership.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">any_data</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">any_vtable</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">data</span> <span class="op">=</span> <span class="ident">Data</span> {
<span class="ident">f</span>,
};
<span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">__rust_maybe_catch_panic</span>(<span class="ident">do_call</span>::<span class="op"><</span><span class="ident">F</span>, <span class="ident">R</span><span class="op">></span>,
<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">data</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">u8</span>,
<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">any_data</span>,
<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">any_vtable</span>);
<span class="kw">return</span> <span class="kw">if</span> <span class="ident">r</span> <span class="op">==</span> <span class="number">0</span> {
<span class="macro">debug_assert</span><span class="macro">!</span>(<span class="ident">update_panic_count</span>(<span class="number">0</span>) <span class="op">==</span> <span class="number">0</span>);
<span class="prelude-val">Ok</span>(<span class="ident">data</span>.<span class="ident">r</span>)
} <span class="kw">else</span> {
<span class="ident">update_panic_count</span>(<span class="op">-</span><span class="number">1</span>);
<span class="macro">debug_assert</span><span class="macro">!</span>(<span class="ident">update_panic_count</span>(<span class="number">0</span>) <span class="op">==</span> <span class="number">0</span>);
<span class="prelude-val">Err</span>(<span class="ident">mem</span>::<span class="ident">transmute</span>(<span class="ident">raw</span>::<span class="ident">TraitObject</span> {
<span class="ident">data</span>: <span class="ident">any_data</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _,
<span class="ident">vtable</span>: <span class="ident">any_vtable</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _,
}))
};
<span class="kw">fn</span> <span class="ident">do_call</span><span class="op"><</span><span class="ident">F</span>: <span class="ident">FnOnce</span>() <span class="op">-></span> <span class="ident">R</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">data</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">u8</span>) {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">data</span> <span class="op">=</span> <span class="ident">data</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">Data</span><span class="op"><</span><span class="ident">F</span>, <span class="ident">R</span><span class="op">></span>;
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="ident">ptr</span>::<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> (<span class="kw-2">*</span><span class="ident">data</span>).<span class="ident">f</span>);
<span class="ident">ptr</span>::<span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> (<span class="kw-2">*</span><span class="ident">data</span>).<span class="ident">r</span>, <span class="ident">f</span>());
}
}
}
<span class="doccomment">/// Determines whether the current thread is unwinding because of panic.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">panicking</span>() <span class="op">-></span> <span class="ident">bool</span> {
<span class="ident">update_panic_count</span>(<span class="number">0</span>) <span class="op">!=</span> <span class="number">0</span>
}
<span class="doccomment">/// Entry point of panic from the libcore crate.</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">test</span>))]</span>
<span class="attribute">#[<span class="ident">lang</span> <span class="op">=</span> <span class="string">"panic_fmt"</span>]</span>
<span class="attribute">#[<span class="ident">unwind</span>]</span>
<span class="kw">pub</span> <span class="kw">extern</span> <span class="kw">fn</span> <span class="ident">rust_begin_panic</span>(<span class="ident">msg</span>: <span class="ident">fmt</span>::<span class="ident">Arguments</span>,
<span class="ident">file</span>: <span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span>,
<span class="ident">line</span>: <span class="ident">u32</span>,
<span class="ident">col</span>: <span class="ident">u32</span>) <span class="op">-></span> <span class="op">!</span> {
<span class="ident">begin_panic_fmt</span>(<span class="kw-2">&</span><span class="ident">msg</span>, <span class="kw-2">&</span>(<span class="ident">file</span>, <span class="ident">line</span>, <span class="ident">col</span>))
}
<span class="doccomment">/// The entry point for panicking with a formatted message.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is designed to reduce the amount of code required at the call</span>
<span class="doccomment">/// site as much as possible (so that `panic!()` has as low an impact</span>
<span class="doccomment">/// on (e.g.) the inlining of other functions as possible), by moving</span>
<span class="doccomment">/// the actual formatting into this shared place.</span>
<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"libstd_sys_internals"</span>,
<span class="ident">reason</span> <span class="op">=</span> <span class="string">"used by the panic! macro"</span>,
<span class="ident">issue</span> <span class="op">=</span> <span class="string">"0"</span>)]</span>
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">never</span>)]</span> <span class="attribute">#[<span class="ident">cold</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">begin_panic_fmt</span>(<span class="ident">msg</span>: <span class="kw-2">&</span><span class="ident">fmt</span>::<span class="ident">Arguments</span>,
<span class="ident">file_line_col</span>: <span class="kw-2">&</span>(<span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span>, <span class="ident">u32</span>, <span class="ident">u32</span>)) <span class="op">-></span> <span class="op">!</span> {
<span class="kw">use</span> <span class="ident">fmt</span>::<span class="ident">Write</span>;
<span class="comment">// We do two allocations here, unfortunately. But (a) they're</span>
<span class="comment">// required with the current scheme, and (b) we don't handle</span>
<span class="comment">// panic + OOM properly anyway (see comment in begin_panic</span>
<span class="comment">// below).</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">new</span>();
<span class="kw">let</span> _ <span class="op">=</span> <span class="ident">s</span>.<span class="ident">write_fmt</span>(<span class="kw-2">*</span><span class="ident">msg</span>);
<span class="ident">begin_panic</span>(<span class="ident">s</span>, <span class="ident">file_line_col</span>)
}
<span class="doccomment">/// This is the entry point of panicking for panic!() and assert!().</span>
<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"libstd_sys_internals"</span>,
<span class="ident">reason</span> <span class="op">=</span> <span class="string">"used by the panic! macro"</span>,
<span class="ident">issue</span> <span class="op">=</span> <span class="string">"0"</span>)]</span>
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">never</span>)]</span> <span class="attribute">#[<span class="ident">cold</span>]</span> <span class="comment">// avoid code bloat at the call sites as much as possible</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">begin_panic</span><span class="op"><</span><span class="ident">M</span>: <span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span>(<span class="ident">msg</span>: <span class="ident">M</span>, <span class="ident">file_line_col</span>: <span class="kw-2">&</span>(<span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span>, <span class="ident">u32</span>, <span class="ident">u32</span>)) <span class="op">-></span> <span class="op">!</span> {
<span class="comment">// Note that this should be the only allocation performed in this code path.</span>
<span class="comment">// Currently this means that panic!() on OOM will invoke this code path,</span>
<span class="comment">// but then again we're not really ready for panic on OOM anyway. If</span>
<span class="comment">// we do start doing this, then we should propagate this allocation to</span>
<span class="comment">// be performed in the parent of this thread instead of the thread that's</span>
<span class="comment">// panicking.</span>
<span class="ident">rust_panic_with_hook</span>(<span class="ident">Box</span>::<span class="ident">new</span>(<span class="ident">msg</span>), <span class="ident">file_line_col</span>)
}
<span class="doccomment">/// Executes the primary logic for a panic, including checking for recursive</span>
<span class="doccomment">/// panics and panic hooks.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is the entry point or panics from libcore, formatted panics, and</span>
<span class="doccomment">/// `Box<Any>` panics. Here we'll verify that we're not panicking recursively,</span>
<span class="doccomment">/// run panic hooks, and then delegate to the actual implementation of panics.</span>
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">never</span>)]</span>
<span class="attribute">#[<span class="ident">cold</span>]</span>
<span class="kw">fn</span> <span class="ident">rust_panic_with_hook</span>(<span class="ident">msg</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span>,
<span class="ident">file_line_col</span>: <span class="kw-2">&</span>(<span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span>, <span class="ident">u32</span>, <span class="ident">u32</span>)) <span class="op">-></span> <span class="op">!</span> {
<span class="kw">let</span> (<span class="ident">file</span>, <span class="ident">line</span>, <span class="ident">col</span>) <span class="op">=</span> <span class="kw-2">*</span><span class="ident">file_line_col</span>;
<span class="kw">let</span> <span class="ident">panics</span> <span class="op">=</span> <span class="ident">update_panic_count</span>(<span class="number">1</span>);
<span class="comment">// If this is the third nested call (e.g. panics == 2, this is 0-indexed),</span>
<span class="comment">// the panic hook probably triggered the last panic, otherwise the</span>
<span class="comment">// double-panic check would have aborted the process. In this case abort the</span>
<span class="comment">// process real quickly as we don't want to try calling it again as it'll</span>
<span class="comment">// probably just panic again.</span>
<span class="kw">if</span> <span class="ident">panics</span> <span class="op">></span> <span class="number">2</span> {
<span class="ident">util</span>::<span class="ident">dumb_print</span>(<span class="macro">format_args</span><span class="macro">!</span>(<span class="string">"thread panicked while processing \
panic. aborting.\n"</span>));
<span class="kw">unsafe</span> { <span class="ident">intrinsics</span>::<span class="ident">abort</span>() }
}
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">info</span> <span class="op">=</span> <span class="ident">PanicInfo</span> {
<span class="ident">payload</span>: <span class="kw-2">&</span><span class="kw-2">*</span><span class="ident">msg</span>,
<span class="ident">location</span>: <span class="ident">Location</span> {
<span class="ident">file</span>,
<span class="ident">line</span>,
<span class="ident">col</span>,
},
};
<span class="ident">HOOK_LOCK</span>.<span class="ident">read</span>();
<span class="kw">match</span> <span class="ident">HOOK</span> {
<span class="ident">Hook</span>::<span class="ident">Default</span> <span class="op">=></span> <span class="ident">default_hook</span>(<span class="kw-2">&</span><span class="ident">info</span>),
<span class="ident">Hook</span>::<span class="ident">Custom</span>(<span class="ident">ptr</span>) <span class="op">=></span> (<span class="kw-2">*</span><span class="ident">ptr</span>)(<span class="kw-2">&</span><span class="ident">info</span>),
}
<span class="ident">HOOK_LOCK</span>.<span class="ident">read_unlock</span>();
}
<span class="kw">if</span> <span class="ident">panics</span> <span class="op">></span> <span class="number">1</span> {
<span class="comment">// If a thread panics while it's already unwinding then we</span>
<span class="comment">// have limited options. Currently our preference is to</span>
<span class="comment">// just abort. In the future we may consider resuming</span>
<span class="comment">// unwinding or otherwise exiting the thread cleanly.</span>
<span class="ident">util</span>::<span class="ident">dumb_print</span>(<span class="macro">format_args</span><span class="macro">!</span>(<span class="string">"thread panicked while panicking. \
aborting.\n"</span>));
<span class="kw">unsafe</span> { <span class="ident">intrinsics</span>::<span class="ident">abort</span>() }
}
<span class="ident">rust_panic</span>(<span class="ident">msg</span>)
}
<span class="doccomment">/// Shim around rust_panic. Called by resume_unwind.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">update_count_then_panic</span>(<span class="ident">msg</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span>) <span class="op">-></span> <span class="op">!</span> {
<span class="ident">update_panic_count</span>(<span class="number">1</span>);
<span class="ident">rust_panic</span>(<span class="ident">msg</span>)
}
<span class="doccomment">/// A private no-mangle function on which to slap yer breakpoints.</span>
<span class="attribute">#[<span class="ident">no_mangle</span>]</span>
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">private_no_mangle_fns</span>)]</span> <span class="comment">// yes we get it, but we like breakpoints</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">rust_panic</span>(<span class="ident">msg</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span>) <span class="op">-></span> <span class="op">!</span> {
<span class="kw">let</span> <span class="ident">code</span> <span class="op">=</span> <span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">obj</span> <span class="op">=</span> <span class="ident">mem</span>::<span class="ident">transmute</span>::<span class="op"><</span>_, <span class="ident">raw</span>::<span class="ident">TraitObject</span><span class="op">></span>(<span class="ident">msg</span>);
<span class="ident">__rust_start_panic</span>(<span class="ident">obj</span>.<span class="ident">data</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">obj</span>.<span class="ident">vtable</span> <span class="kw">as</span> <span class="ident">usize</span>)
};
<span class="macro">rtabort</span><span class="macro">!</span>(<span class="string">"failed to initiate panic, error {}"</span>, <span class="ident">code</span>)
}
</pre>
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