<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source to the Rust file `libstd/sys_common/backtrace.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>backtrace.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span> <span id="2"> 2</span> <span id="3"> 3</span> <span id="4"> 4</span> <span id="5"> 5</span> <span id="6"> 6</span> <span id="7"> 7</span> <span id="8"> 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id="431">431</span> <span id="432">432</span> <span id="433">433</span> <span id="434">434</span> <span id="435">435</span> <span id="436">436</span> <span id="437">437</span> <span id="438">438</span> <span id="439">439</span> <span id="440">440</span> <span id="441">441</span> <span id="442">442</span> <span id="443">443</span> <span id="444">444</span> <span id="445">445</span> <span id="446">446</span> <span id="447">447</span> <span id="448">448</span> <span id="449">449</span> <span id="450">450</span> <span id="451">451</span> <span id="452">452</span> <span id="453">453</span> <span id="454">454</span> <span id="455">455</span> <span id="456">456</span> <span id="457">457</span> <span id="458">458</span> <span id="459">459</span> <span id="460">460</span> <span id="461">461</span> <span id="462">462</span> <span id="463">463</span> </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">/// Common code for printing the backtrace in the same way across the different</span> <span class="doccomment">/// supported platforms.</span> <span class="kw">use</span> <span class="ident">env</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">io</span>; <span class="kw">use</span> <span class="ident">str</span>; <span class="kw">use</span> <span class="ident">sync</span>::<span class="ident">atomic</span>::{<span class="self">self</span>, <span class="ident">Ordering</span>}; <span class="kw">use</span> <span class="ident">path</span>::{<span class="self">self</span>, <span class="ident">Path</span>}; <span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">mutex</span>::<span class="ident">Mutex</span>; <span class="kw">use</span> <span class="ident">ptr</span>; <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">backtrace</span>::{ <span class="ident">unwind_backtrace</span>, <span class="ident">resolve_symname</span>, <span class="ident">foreach_symbol_fileline</span>, <span class="ident">BacktraceContext</span> }; <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">target_pointer_width</span> <span class="op">=</span> <span class="string">"64"</span>)]</span> <span class="kw">pub</span> <span class="kw">const</span> <span class="ident">HEX_WIDTH</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">18</span>; <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">target_pointer_width</span> <span class="op">=</span> <span class="string">"32"</span>)]</span> <span class="kw">pub</span> <span class="kw">const</span> <span class="ident">HEX_WIDTH</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">10</span>; <span class="doccomment">/// Represents an item in the backtrace list. See `unwind_backtrace` for how</span> <span class="doccomment">/// it is created.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>, <span class="ident">Copy</span>, <span class="ident">Clone</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Frame</span> { <span class="doccomment">/// Exact address of the call that failed.</span> <span class="kw">pub</span> <span class="ident">exact_position</span>: <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">u8</span>, <span class="doccomment">/// Address of the enclosing function.</span> <span class="kw">pub</span> <span class="ident">symbol_addr</span>: <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">u8</span>, <span class="doccomment">/// Which inlined function is this frame referring to</span> <span class="kw">pub</span> <span class="ident">inline_context</span>: <span class="ident">u32</span>, } <span class="doccomment">/// Max number of frames to print.</span> <span class="kw">const</span> <span class="ident">MAX_NB_FRAMES</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">100</span>; <span class="doccomment">/// Prints the current backtrace.</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">print</span>(<span class="ident">w</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Write</span>, <span class="ident">format</span>: <span class="ident">PrintFormat</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="kw">static</span> <span class="ident">LOCK</span>: <span class="ident">Mutex</span> <span class="op">=</span> <span class="ident">Mutex</span>::<span class="ident">new</span>(); <span class="comment">// Use a lock to prevent mixed output in multithreading context.</span> <span class="comment">// Some platforms also requires it, like `SymFromAddr` on Windows.</span> <span class="kw">unsafe</span> { <span class="ident">LOCK</span>.<span class="ident">lock</span>(); <span class="kw">let</span> <span class="ident">res</span> <span class="op">=</span> <span class="ident">_print</span>(<span class="ident">w</span>, <span class="ident">format</span>); <span class="ident">LOCK</span>.<span class="ident">unlock</span>(); <span class="ident">res</span> } } <span class="kw">fn</span> <span class="ident">_print</span>(<span class="ident">w</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Write</span>, <span class="ident">format</span>: <span class="ident">PrintFormat</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">frames</span> <span class="op">=</span> [<span class="ident">Frame</span> { <span class="ident">exact_position</span>: <span class="ident">ptr</span>::<span class="ident">null</span>(), <span class="ident">symbol_addr</span>: <span class="ident">ptr</span>::<span class="ident">null</span>(), <span class="ident">inline_context</span>: <span class="number">0</span>, }; <span class="ident">MAX_NB_FRAMES</span>]; <span class="kw">let</span> (<span class="ident">nb_frames</span>, <span class="ident">context</span>) <span class="op">=</span> <span class="ident">unwind_backtrace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">frames</span>)<span class="question-mark">?</span>; <span class="kw">let</span> (<span class="ident">skipped_before</span>, <span class="ident">skipped_after</span>) <span class="op">=</span> <span class="ident">filter_frames</span>(<span class="kw-2">&</span><span class="ident">frames</span>[..<span class="ident">nb_frames</span>], <span class="ident">format</span>, <span class="kw-2">&</span><span class="ident">context</span>); <span class="kw">if</span> <span class="ident">skipped_before</span> <span class="op">+</span> <span class="ident">skipped_after</span> <span class="op">></span> <span class="number">0</span> { <span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">"note: Some details are omitted, \ run with `RUST_BACKTRACE=full` for a verbose backtrace."</span>)<span class="question-mark">?</span>; } <span class="macro">writeln</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">"stack backtrace:"</span>)<span class="question-mark">?</span>; <span class="kw">let</span> <span class="ident">filtered_frames</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">frames</span>[..<span class="ident">nb_frames</span> <span class="op">-</span> <span class="ident">skipped_after</span>]; <span class="kw">for</span> (<span class="ident">index</span>, <span class="ident">frame</span>) <span class="kw">in</span> <span class="ident">filtered_frames</span>.<span class="ident">iter</span>().<span class="ident">skip</span>(<span class="ident">skipped_before</span>).<span class="ident">enumerate</span>() { <span class="ident">resolve_symname</span>(<span class="kw-2">*</span><span class="ident">frame</span>, <span class="op">|</span><span class="ident">symname</span><span class="op">|</span> { <span class="ident">output</span>(<span class="ident">w</span>, <span class="ident">index</span>, <span class="kw-2">*</span><span class="ident">frame</span>, <span class="ident">symname</span>, <span class="ident">format</span>) }, <span class="kw-2">&</span><span class="ident">context</span>)<span class="question-mark">?</span>; <span class="kw">let</span> <span class="ident">has_more_filenames</span> <span class="op">=</span> <span class="ident">foreach_symbol_fileline</span>(<span class="kw-2">*</span><span class="ident">frame</span>, <span class="op">|</span><span class="ident">file</span>, <span class="ident">line</span><span class="op">|</span> { <span class="ident">output_fileline</span>(<span class="ident">w</span>, <span class="ident">file</span>, <span class="ident">line</span>, <span class="ident">format</span>) }, <span class="kw-2">&</span><span class="ident">context</span>)<span class="question-mark">?</span>; <span class="kw">if</span> <span class="ident">has_more_filenames</span> { <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="string">b" <... and possibly more>"</span>)<span class="question-mark">?</span>; } } <span class="prelude-val">Ok</span>(()) } <span class="doccomment">/// Returns a number of frames to remove at the beginning and at the end of the</span> <span class="doccomment">/// backtrace, according to the backtrace format.</span> <span class="kw">fn</span> <span class="ident">filter_frames</span>(<span class="ident">frames</span>: <span class="kw-2">&</span>[<span class="ident">Frame</span>], <span class="ident">format</span>: <span class="ident">PrintFormat</span>, <span class="ident">context</span>: <span class="kw-2">&</span><span class="ident">BacktraceContext</span>) <span class="op">-></span> (<span class="ident">usize</span>, <span class="ident">usize</span>) { <span class="kw">if</span> <span class="ident">format</span> <span class="op">==</span> <span class="ident">PrintFormat</span>::<span class="ident">Full</span> { <span class="kw">return</span> (<span class="number">0</span>, <span class="number">0</span>); } <span class="kw">let</span> <span class="ident">skipped_before</span> <span class="op">=</span> <span class="number">0</span>; <span class="kw">let</span> <span class="ident">skipped_after</span> <span class="op">=</span> <span class="ident">frames</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="ident">frames</span>.<span class="ident">iter</span>().<span class="ident">position</span>(<span class="op">|</span><span class="ident">frame</span><span class="op">|</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">is_marker</span> <span class="op">=</span> <span class="bool-val">false</span>; <span class="kw">let</span> <span class="kw">_</span> <span class="op">=</span> <span class="ident">resolve_symname</span>(<span class="kw-2">*</span><span class="ident">frame</span>, <span class="op">|</span><span class="ident">symname</span><span class="op">|</span> { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">mangled_symbol_name</span>) <span class="op">=</span> <span class="ident">symname</span> { <span class="comment">// Use grep to find the concerned functions</span> <span class="kw">if</span> <span class="ident">mangled_symbol_name</span>.<span class="ident">contains</span>(<span class="string">"__rust_begin_short_backtrace"</span>) { <span class="ident">is_marker</span> <span class="op">=</span> <span class="bool-val">true</span>; } } <span class="prelude-val">Ok</span>(()) }, <span class="ident">context</span>); <span class="ident">is_marker</span> }).<span class="ident">unwrap_or</span>(<span class="ident">frames</span>.<span class="ident">len</span>()); <span class="kw">if</span> <span class="ident">skipped_before</span> <span class="op">+</span> <span class="ident">skipped_after</span> <span class="op">>=</span> <span class="ident">frames</span>.<span class="ident">len</span>() { <span class="comment">// Avoid showing completely empty backtraces</span> <span class="kw">return</span> (<span class="number">0</span>, <span class="number">0</span>); } (<span class="ident">skipped_before</span>, <span class="ident">skipped_after</span>) } <span class="doccomment">/// Fixed frame used to clean the backtrace with `RUST_BACKTRACE=1`.</span> <span class="attribute">#[<span class="ident">inline</span>(<span class="ident">never</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">__rust_begin_short_backtrace</span><span class="op"><</span><span class="ident">F</span>, <span class="ident">T</span><span class="op">></span>(<span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="ident">T</span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnOnce</span>() <span class="op">-></span> <span class="ident">T</span>, <span class="ident">F</span>: <span class="ident">Send</span>, <span class="ident">T</span>: <span class="ident">Send</span> { <span class="ident">f</span>() } <span class="doccomment">/// Controls how the backtrace should be formatted.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>, <span class="ident">Copy</span>, <span class="ident">Clone</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span> <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">PrintFormat</span> { <span class="doccomment">/// Show only relevant data from the backtrace.</span> <span class="ident">Short</span> <span class="op">=</span> <span class="number">2</span>, <span class="doccomment">/// Show all the frames with absolute path for files.</span> <span class="ident">Full</span> <span class="op">=</span> <span class="number">3</span>, } <span class="comment">// For now logging is turned off by default, and this function checks to see</span> <span class="comment">// whether the magical environment variable is present to see if it's turned on.</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">log_enabled</span>() <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">PrintFormat</span><span class="op">></span> { <span class="kw">static</span> <span class="ident">ENABLED</span>: <span class="ident">atomic</span>::<span class="ident">AtomicIsize</span> <span class="op">=</span> <span class="ident">atomic</span>::<span class="ident">AtomicIsize</span>::<span class="ident">new</span>(<span class="number">0</span>); <span class="kw">match</span> <span class="ident">ENABLED</span>.<span class="ident">load</span>(<span class="ident">Ordering</span>::<span class="ident">SeqCst</span>) { <span class="number">0</span> <span class="op">=></span> {} <span class="number">1</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="number">2</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="ident">PrintFormat</span>::<span class="ident">Short</span>), <span class="kw">_</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="ident">PrintFormat</span>::<span class="ident">Full</span>), } <span class="kw">let</span> <span class="ident">val</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">env</span>::<span class="ident">var_os</span>(<span class="string">"RUST_BACKTRACE"</span>) { <span class="prelude-val">Some</span>(<span class="ident">x</span>) <span class="op">=></span> <span class="kw">if</span> <span class="kw-2">&</span><span class="ident">x</span> <span class="op">==</span> <span class="string">"0"</span> { <span class="prelude-val">None</span> } <span class="kw">else</span> <span class="kw">if</span> <span class="kw-2">&</span><span class="ident">x</span> <span class="op">==</span> <span class="string">"full"</span> { <span class="prelude-val">Some</span>(<span class="ident">PrintFormat</span>::<span class="ident">Full</span>) } <span class="kw">else</span> { <span class="prelude-val">Some</span>(<span class="ident">PrintFormat</span>::<span class="ident">Short</span>) }, <span class="prelude-val">None</span> <span class="op">=></span> <span class="prelude-val">None</span>, }; <span class="ident">ENABLED</span>.<span class="ident">store</span>(<span class="kw">match</span> <span class="ident">val</span> { <span class="prelude-val">Some</span>(<span class="ident">v</span>) <span class="op">=></span> <span class="ident">v</span> <span class="kw">as</span> <span class="ident">isize</span>, <span class="prelude-val">None</span> <span class="op">=></span> <span class="number">1</span>, }, <span class="ident">Ordering</span>::<span class="ident">SeqCst</span>); <span class="ident">val</span> } <span class="doccomment">/// Print the symbol of the backtrace frame.</span> <span class="doccomment">///</span> <span class="doccomment">/// These output functions should now be used everywhere to ensure consistency.</span> <span class="doccomment">/// You may want to also use `output_fileline`.</span> <span class="kw">fn</span> <span class="ident">output</span>(<span class="ident">w</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Write</span>, <span class="ident">idx</span>: <span class="ident">usize</span>, <span class="ident">frame</span>: <span class="ident">Frame</span>, <span class="ident">s</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">str</span><span class="op">></span>, <span class="ident">format</span>: <span class="ident">PrintFormat</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="comment">// Remove the `17: 0x0 - <unknown>` line.</span> <span class="kw">if</span> <span class="ident">format</span> <span class="op">==</span> <span class="ident">PrintFormat</span>::<span class="ident">Short</span> <span class="op">&&</span> <span class="ident">frame</span>.<span class="ident">exact_position</span> <span class="op">==</span> <span class="ident">ptr</span>::<span class="ident">null</span>() { <span class="kw">return</span> <span class="prelude-val">Ok</span>(()); } <span class="kw">match</span> <span class="ident">format</span> { <span class="ident">PrintFormat</span>::<span class="ident">Full</span> <span class="op">=></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">" {:2}: {:2$?} - "</span>, <span class="ident">idx</span>, <span class="ident">frame</span>.<span class="ident">exact_position</span>, <span class="ident">HEX_WIDTH</span>)<span class="question-mark">?</span>, <span class="ident">PrintFormat</span>::<span class="ident">Short</span> <span class="op">=></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">" {:2}: "</span>, <span class="ident">idx</span>)<span class="question-mark">?</span>, } <span class="kw">match</span> <span class="ident">s</span> { <span class="prelude-val">Some</span>(<span class="ident">string</span>) <span class="op">=></span> <span class="ident">demangle</span>(<span class="ident">w</span>, <span class="ident">string</span>, <span class="ident">format</span>)<span class="question-mark">?</span>, <span class="prelude-val">None</span> <span class="op">=></span> <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="string">b"<unknown>"</span>)<span class="question-mark">?</span>, } <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="string">b"\n"</span>) } <span class="doccomment">/// Print the filename and line number of the backtrace frame.</span> <span class="doccomment">///</span> <span class="doccomment">/// See also `output`.</span> <span class="attribute">#[<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span> <span class="kw">fn</span> <span class="ident">output_fileline</span>(<span class="ident">w</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Write</span>, <span class="ident">file</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">line</span>: <span class="ident">u32</span>, <span class="ident">format</span>: <span class="ident">PrintFormat</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="comment">// prior line: " ##: {:2$} - func"</span> <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="string">b""</span>)<span class="question-mark">?</span>; <span class="kw">match</span> <span class="ident">format</span> { <span class="ident">PrintFormat</span>::<span class="ident">Full</span> <span class="op">=></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">" {:1$}"</span>, <span class="string">""</span>, <span class="ident">HEX_WIDTH</span>)<span class="question-mark">?</span>, <span class="ident">PrintFormat</span>::<span class="ident">Short</span> <span class="op">=></span> <span class="macro">write</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">" "</span>)<span class="question-mark">?</span>, } <span class="kw">let</span> <span class="ident">file</span> <span class="op">=</span> <span class="ident">str</span>::<span class="ident">from_utf8</span>(<span class="ident">file</span>).<span class="ident">unwrap_or</span>(<span class="string">"<unknown>"</span>); <span class="kw">let</span> <span class="ident">file_path</span> <span class="op">=</span> <span class="ident">Path</span>::<span class="ident">new</span>(<span class="ident">file</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">already_printed</span> <span class="op">=</span> <span class="bool-val">false</span>; <span class="kw">if</span> <span class="ident">format</span> <span class="op">==</span> <span class="ident">PrintFormat</span>::<span class="ident">Short</span> <span class="op">&&</span> <span class="ident">file_path</span>.<span class="ident">is_absolute</span>() { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Ok</span>(<span class="ident">cwd</span>) <span class="op">=</span> <span class="ident">env</span>::<span class="ident">current_dir</span>() { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Ok</span>(<span class="ident">stripped</span>) <span class="op">=</span> <span class="ident">file_path</span>.<span class="ident">strip_prefix</span>(<span class="kw-2">&</span><span class="ident">cwd</span>) { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">s</span>) <span class="op">=</span> <span class="ident">stripped</span>.<span class="ident">to_str</span>() { <span class="macro">write</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">" at .{}{}:{}"</span>, <span class="ident">path</span>::<span class="ident">MAIN_SEPARATOR</span>, <span class="ident">s</span>, <span class="ident">line</span>)<span class="question-mark">?</span>; <span class="ident">already_printed</span> <span class="op">=</span> <span class="bool-val">true</span>; } } } } <span class="kw">if</span> <span class="op">!</span><span class="ident">already_printed</span> { <span class="macro">write</span><span class="macro">!</span>(<span class="ident">w</span>, <span class="string">" at {}:{}"</span>, <span class="ident">file</span>, <span class="ident">line</span>)<span class="question-mark">?</span>; } <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="string">b"\n"</span>) } <span class="comment">// All rust symbols are in theory lists of "::"-separated identifiers. Some</span> <span class="comment">// assemblers, however, can't handle these characters in symbol names. To get</span> <span class="comment">// around this, we use C++-style mangling. The mangling method is:</span> <span class="comment">//</span> <span class="comment">// 1. Prefix the symbol with "_ZN"</span> <span class="comment">// 2. For each element of the path, emit the length plus the element</span> <span class="comment">// 3. End the path with "E"</span> <span class="comment">//</span> <span class="comment">// For example, "_ZN4testE" => "test" and "_ZN3foo3barE" => "foo::bar".</span> <span class="comment">//</span> <span class="comment">// We're the ones printing our backtraces, so we can't rely on anything else to</span> <span class="comment">// demangle our symbols. It's *much* nicer to look at demangled symbols, so</span> <span class="comment">// this function is implemented to give us nice pretty output.</span> <span class="comment">//</span> <span class="comment">// Note that this demangler isn't quite as fancy as it could be. We have lots</span> <span class="comment">// of other information in our symbols like hashes, version, type information,</span> <span class="comment">// etc. Additionally, this doesn't handle glue symbols at all.</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">demangle</span>(<span class="ident">writer</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Write</span>, <span class="kw-2">mut</span> <span class="ident">s</span>: <span class="kw-2">&</span><span class="ident">str</span>, <span class="ident">format</span>: <span class="ident">PrintFormat</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="comment">// During ThinLTO LLVM may import and rename internal symbols, so strip out</span> <span class="comment">// those endings first as they're one of the last manglings applied to</span> <span class="comment">// symbol names.</span> <span class="kw">let</span> <span class="ident">llvm</span> <span class="op">=</span> <span class="string">".llvm."</span>; <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">i</span>) <span class="op">=</span> <span class="ident">s</span>.<span class="ident">find</span>(<span class="ident">llvm</span>) { <span class="kw">let</span> <span class="ident">candidate</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">s</span>[<span class="ident">i</span> <span class="op">+</span> <span class="ident">llvm</span>.<span class="ident">len</span>()..]; <span class="kw">let</span> <span class="ident">all_hex</span> <span class="op">=</span> <span class="ident">candidate</span>.<span class="ident">chars</span>().<span class="ident">all</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> { <span class="kw">match</span> <span class="ident">c</span> { <span class="string">'A'</span> ... <span class="string">'F'</span> <span class="op">|</span> <span class="string">'0'</span> ... <span class="string">'9'</span> <span class="op">=></span> <span class="bool-val">true</span>, <span class="kw">_</span> <span class="op">=></span> <span class="bool-val">false</span>, } }); <span class="kw">if</span> <span class="ident">all_hex</span> { <span class="ident">s</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">s</span>[..<span class="ident">i</span>]; } } <span class="comment">// Validate the symbol. If it doesn't look like anything we're</span> <span class="comment">// expecting, we just print it literally. Note that we must handle non-rust</span> <span class="comment">// symbols because we could have any function in the backtrace.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">valid</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">inner</span> <span class="op">=</span> <span class="ident">s</span>; <span class="kw">if</span> <span class="ident">s</span>.<span class="ident">len</span>() <span class="op">></span> <span class="number">4</span> <span class="op">&&</span> <span class="ident">s</span>.<span class="ident">starts_with</span>(<span class="string">"_ZN"</span>) <span class="op">&&</span> <span class="ident">s</span>.<span class="ident">ends_with</span>(<span class="string">"E"</span>) { <span class="ident">inner</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">s</span>[<span class="number">3</span> .. <span class="ident">s</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="number">1</span>]; <span class="comment">// On Windows, dbghelp strips leading underscores, so we accept "ZN...E" form too.</span> } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">s</span>.<span class="ident">len</span>() <span class="op">></span> <span class="number">3</span> <span class="op">&&</span> <span class="ident">s</span>.<span class="ident">starts_with</span>(<span class="string">"ZN"</span>) <span class="op">&&</span> <span class="ident">s</span>.<span class="ident">ends_with</span>(<span class="string">"E"</span>) { <span class="ident">inner</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">s</span>[<span class="number">2</span> .. <span class="ident">s</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="number">1</span>]; } <span class="kw">else</span> { <span class="ident">valid</span> <span class="op">=</span> <span class="bool-val">false</span>; } <span class="kw">if</span> <span class="ident">valid</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">chars</span> <span class="op">=</span> <span class="ident">inner</span>.<span class="ident">chars</span>(); <span class="kw">while</span> <span class="ident">valid</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="number">0</span>; <span class="kw">for</span> <span class="ident">c</span> <span class="kw">in</span> <span class="ident">chars</span>.<span class="ident">by_ref</span>() { <span class="kw">if</span> <span class="ident">c</span>.<span class="ident">is_numeric</span>() { <span class="ident">i</span> <span class="op">=</span> <span class="ident">i</span> <span class="op">*</span> <span class="number">10</span> <span class="op">+</span> <span class="ident">c</span> <span class="kw">as</span> <span class="ident">usize</span> <span class="op">-</span> <span class="string">'0'</span> <span class="kw">as</span> <span class="ident">usize</span>; } <span class="kw">else</span> { <span class="kw">break</span> } } <span class="kw">if</span> <span class="ident">i</span> <span class="op">==</span> <span class="number">0</span> { <span class="ident">valid</span> <span class="op">=</span> <span class="ident">chars</span>.<span class="ident">next</span>().<span class="ident">is_none</span>(); <span class="kw">break</span> } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">chars</span>.<span class="ident">by_ref</span>().<span class="ident">take</span>(<span class="ident">i</span> <span class="op">-</span> <span class="number">1</span>).<span class="ident">count</span>() <span class="op">!=</span> <span class="ident">i</span> <span class="op">-</span> <span class="number">1</span> { <span class="ident">valid</span> <span class="op">=</span> <span class="bool-val">false</span>; } } } <span class="comment">// Alright, let's do this.</span> <span class="kw">if</span> <span class="op">!</span><span class="ident">valid</span> { <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="ident">s</span>.<span class="ident">as_bytes</span>())<span class="question-mark">?</span>; } <span class="kw">else</span> { <span class="comment">// remove the `::hfc2edb670e5eda97` part at the end of the symbol.</span> <span class="kw">if</span> <span class="ident">format</span> <span class="op">==</span> <span class="ident">PrintFormat</span>::<span class="ident">Short</span> { <span class="comment">// The symbol in still mangled.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">split</span> <span class="op">=</span> <span class="ident">inner</span>.<span class="ident">rsplitn</span>(<span class="number">2</span>, <span class="string">"17h"</span>); <span class="kw">match</span> (<span class="ident">split</span>.<span class="ident">next</span>(), <span class="ident">split</span>.<span class="ident">next</span>()) { (<span class="prelude-val">Some</span>(<span class="ident">addr</span>), <span class="ident">rest</span>) <span class="op">=></span> { <span class="kw">if</span> <span class="ident">addr</span>.<span class="ident">len</span>() <span class="op">==</span> <span class="number">16</span> <span class="op">&&</span> <span class="ident">addr</span>.<span class="ident">chars</span>().<span class="ident">all</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> <span class="ident">c</span>.<span class="ident">is_digit</span>(<span class="number">16</span>)) { <span class="ident">inner</span> <span class="op">=</span> <span class="ident">rest</span>.<span class="ident">unwrap_or</span>(<span class="string">""</span>); } } <span class="kw">_</span> <span class="op">=></span> (), } } <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">first</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="kw">while</span> <span class="op">!</span><span class="ident">inner</span>.<span class="ident">is_empty</span>() { <span class="kw">if</span> <span class="op">!</span><span class="ident">first</span> { <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="string">b"::"</span>)<span class="question-mark">?</span>; } <span class="kw">else</span> { <span class="ident">first</span> <span class="op">=</span> <span class="bool-val">false</span>; } <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rest</span> <span class="op">=</span> <span class="ident">inner</span>; <span class="kw">while</span> <span class="ident">rest</span>.<span class="ident">chars</span>().<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">is_numeric</span>() { <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="number">1</span>..]; } <span class="kw">let</span> <span class="ident">i</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="ident">inner</span>[.. (<span class="ident">inner</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="ident">rest</span>.<span class="ident">len</span>())].<span class="ident">parse</span>().<span class="ident">unwrap</span>(); <span class="ident">inner</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="ident">i</span>..]; <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[..<span class="ident">i</span>]; <span class="kw">if</span> <span class="ident">rest</span>.<span class="ident">starts_with</span>(<span class="string">"_$"</span>) { <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="number">1</span>..]; } <span class="kw">while</span> <span class="op">!</span><span class="ident">rest</span>.<span class="ident">is_empty</span>() { <span class="kw">if</span> <span class="ident">rest</span>.<span class="ident">starts_with</span>(<span class="string">"."</span>) { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="string">'.'</span>) <span class="op">=</span> <span class="ident">rest</span>[<span class="number">1</span>..].<span class="ident">chars</span>().<span class="ident">next</span>() { <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="string">b"::"</span>)<span class="question-mark">?</span>; <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="number">2</span>..]; } <span class="kw">else</span> { <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="string">b"."</span>)<span class="question-mark">?</span>; <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="number">1</span>..]; } } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">rest</span>.<span class="ident">starts_with</span>(<span class="string">"$"</span>) { <span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">demangle</span> { ($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pat</span>:<span class="ident">expr</span> <span class="op">=></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">demangled</span>:<span class="ident">expr</span>),<span class="kw-2">*</span>) <span class="op">=></span> ({ $(<span class="kw">if</span> <span class="ident">rest</span>.<span class="ident">starts_with</span>(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pat</span>) { <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">demangled</span>)<span class="question-mark">?</span>; <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pat</span>.<span class="ident">len</span>()..]; } <span class="kw">else</span>)<span class="op">*</span> { <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="ident">rest</span>.<span class="ident">as_bytes</span>())<span class="question-mark">?</span>; <span class="kw">break</span>; } }) } <span class="comment">// see src/librustc/back/link.rs for these mappings</span> <span class="macro">demangle</span><span class="macro">!</span> ( <span class="string">"$SP$"</span> <span class="op">=></span> <span class="string">b"@"</span>, <span class="string">"$BP$"</span> <span class="op">=></span> <span class="string">b"*"</span>, <span class="string">"$RF$"</span> <span class="op">=></span> <span class="string">b"&"</span>, <span class="string">"$LT$"</span> <span class="op">=></span> <span class="string">b"<"</span>, <span class="string">"$GT$"</span> <span class="op">=></span> <span class="string">b">"</span>, <span class="string">"$LP$"</span> <span class="op">=></span> <span class="string">b"("</span>, <span class="string">"$RP$"</span> <span class="op">=></span> <span class="string">b")"</span>, <span class="string">"$C$"</span> <span class="op">=></span> <span class="string">b","</span>, <span class="comment">// in theory we can demangle any Unicode code point, but</span> <span class="comment">// for simplicity we just catch the common ones.</span> <span class="string">"$u7e$"</span> <span class="op">=></span> <span class="string">b"~"</span>, <span class="string">"$u20$"</span> <span class="op">=></span> <span class="string">b" "</span>, <span class="string">"$u27$"</span> <span class="op">=></span> <span class="string">b"'"</span>, <span class="string">"$u5b$"</span> <span class="op">=></span> <span class="string">b"["</span>, <span class="string">"$u5d$"</span> <span class="op">=></span> <span class="string">b"]"</span>, <span class="string">"$u7b$"</span> <span class="op">=></span> <span class="string">b"{"</span>, <span class="string">"$u7d$"</span> <span class="op">=></span> <span class="string">b"}"</span>, <span class="string">"$u3b$"</span> <span class="op">=></span> <span class="string">b";"</span>, <span class="string">"$u2b$"</span> <span class="op">=></span> <span class="string">b"+"</span>, <span class="string">"$u22$"</span> <span class="op">=></span> <span class="string">b"\""</span> ) } <span class="kw">else</span> { <span class="kw">let</span> <span class="ident">idx</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">rest</span>.<span class="ident">char_indices</span>().<span class="ident">find</span>(<span class="op">|</span><span class="kw-2">&</span>(<span class="kw">_</span>, <span class="ident">c</span>)<span class="op">|</span> <span class="ident">c</span> <span class="op">==</span> <span class="string">'$'</span> <span class="op">||</span> <span class="ident">c</span> <span class="op">==</span> <span class="string">'.'</span>) { <span class="prelude-val">None</span> <span class="op">=></span> <span class="ident">rest</span>.<span class="ident">len</span>(), <span class="prelude-val">Some</span>((<span class="ident">i</span>, <span class="kw">_</span>)) <span class="op">=></span> <span class="ident">i</span>, }; <span class="ident">writer</span>.<span class="ident">write_all</span>(<span class="ident">rest</span>[..<span class="ident">idx</span>].<span class="ident">as_bytes</span>())<span class="question-mark">?</span>; <span class="ident">rest</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">rest</span>[<span class="ident">idx</span>..]; } } } } <span class="prelude-val">Ok</span>(()) } <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> <span class="kw">mod</span> <span class="ident">tests</span> { <span class="kw">use</span> <span class="ident">sys_common</span>; <span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">t</span> { (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">b</span>:<span class="ident">expr</span>) <span class="op">=></span> ({ <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">m</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>(); <span class="ident">sys_common</span>::<span class="ident">backtrace</span>::<span class="ident">demangle</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">m</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="kw">super</span>::<span class="ident">PrintFormat</span>::<span class="ident">Full</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">String</span>::<span class="ident">from_utf8</span>(<span class="ident">m</span>).<span class="ident">unwrap</span>(), <span class="macro-nonterminal">$</span><span class="macro-nonterminal">b</span>); }) } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">demangle</span>() { <span class="macro">t</span><span class="macro">!</span>(<span class="string">"test"</span>, <span class="string">"test"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN4testE"</span>, <span class="string">"test"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN4test"</span>, <span class="string">"_ZN4test"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN4test1a2bcE"</span>, <span class="string">"test::a::bc"</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">demangle_dollars</span>() { <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN4$RP$E"</span>, <span class="string">")"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN8$RF$testE"</span>, <span class="string">"&test"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN8$BP$test4foobE"</span>, <span class="string">"*test::foob"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN9$u20$test4foobE"</span>, <span class="string">" test::foob"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN35Bar$LT$$u5b$u32$u3b$$u20$4$u5d$$GT$E"</span>, <span class="string">"Bar<[u32; 4]>"</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">demangle_many_dollars</span>() { <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN13test$u20$test4foobE"</span>, <span class="string">"test test::foob"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN12test$BP$test4foobE"</span>, <span class="string">"test*test::foob"</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">demangle_windows</span>() { <span class="macro">t</span><span class="macro">!</span>(<span class="string">"ZN4testE"</span>, <span class="string">"test"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"ZN13test$u20$test4foobE"</span>, <span class="string">"test test::foob"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"ZN12test$RF$test4foobE"</span>, <span class="string">"test&test::foob"</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">demangle_elements_beginning_with_underscore</span>() { <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN13_$LT$test$GT$E"</span>, <span class="string">"<test>"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN28_$u7b$$u7b$closure$u7d$$u7d$E"</span>, <span class="string">"{{closure}}"</span>); <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN15__STATIC_FMTSTRE"</span>, <span class="string">"__STATIC_FMTSTR"</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">demangle_trait_impls</span>() { <span class="macro">t</span><span class="macro">!</span>(<span class="string">"_ZN71_$LT$Test$u20$$u2b$$u20$$u27$static$u20$as$u20$foo..Bar$LT$Test$GT$$GT$3barE"</span>, <span class="string">"<Test + 'static as foo::Bar<Test>>::bar"</span>); } } </pre> </section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../";window.currentCrate = "std";</script><script src="../../../aliases.js"></script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>