<!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 of the Rust file `src/rt.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>rt.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceSerif4-Regular-1f7d512b176f0f72.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceSerif4-Bold-124a1ca42af929b6.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><link rel="stylesheet" href="../../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../static.files/rustdoc-6827029ac823cab7.css" id="mainThemeStyle"><link rel="stylesheet" id="themeStyle" href="../../static.files/light-ebce58d0a40c3431.css"><link rel="stylesheet" disabled href="../../static.files/dark-f23faae4a2daf9a6.css"><link rel="stylesheet" disabled href="../../static.files/ayu-8af5e100b21cd173.css"><script id="default-settings" ></script><script src="../../static.files/storage-d43fa987303ecbbb.js"></script><script defer src="../../static.files/source-script-5cf2e01a42cc9858.js"></script><script defer src="../../source-files.js"></script><script defer src="../../static.files/main-c55e1eb52e1886b4.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-13285aec31fa243e.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-16x16-8b506e7a72182f1c.png"><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../juicebox_asm/index.html"><img class="rust-logo" src="../../static.files/rust-logo-151179464ae7ed46.svg" alt="logo"></a><form class="search-form"><span></span><input class="search-input" name="search" aria-label="Run search in the documentation" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../static.files/wheel-5ec35bf9ca753509.svg"></a></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><a href="#1" id="1">1</a> <a href="#2" id="2">2</a> <a href="#3" id="3">3</a> <a href="#4" id="4">4</a> <a href="#5" id="5">5</a> <a href="#6" id="6">6</a> <a href="#7" id="7">7</a> <a href="#8" id="8">8</a> <a href="#9" id="9">9</a> <a href="#10" id="10">10</a> <a href="#11" id="11">11</a> <a href="#12" id="12">12</a> <a href="#13" id="13">13</a> <a href="#14" id="14">14</a> <a href="#15" id="15">15</a> <a href="#16" id="16">16</a> <a href="#17" id="17">17</a> <a href="#18" id="18">18</a> <a href="#19" id="19">19</a> <a href="#20" id="20">20</a> <a href="#21" id="21">21</a> <a href="#22" id="22">22</a> <a href="#23" id="23">23</a> <a href="#24" id="24">24</a> <a href="#25" id="25">25</a> <a href="#26" id="26">26</a> <a href="#27" id="27">27</a> <a href="#28" id="28">28</a> <a href="#29" id="29">29</a> <a href="#30" id="30">30</a> <a href="#31" id="31">31</a> <a href="#32" id="32">32</a> <a href="#33" id="33">33</a> <a href="#34" id="34">34</a> <a href="#35" id="35">35</a> <a href="#36" id="36">36</a> <a href="#37" id="37">37</a> <a href="#38" id="38">38</a> <a href="#39" id="39">39</a> <a href="#40" id="40">40</a> <a href="#41" id="41">41</a> <a href="#42" id="42">42</a> <a href="#43" id="43">43</a> <a href="#44" id="44">44</a> <a href="#45" id="45">45</a> <a href="#46" id="46">46</a> <a href="#47" id="47">47</a> <a href="#48" id="48">48</a> <a href="#49" id="49">49</a> <a href="#50" id="50">50</a> <a href="#51" id="51">51</a> <a href="#52" id="52">52</a> <a href="#53" id="53">53</a> <a href="#54" id="54">54</a> </pre><pre class="rust"><code><span class="doccomment">//! A simple runtime which can be used to execute emitted instructions. </span><span class="kw">use </span>core::ffi::c_void; <span class="kw">use </span>nix::sys::mman::{mmap, munmap, MapFlags, ProtFlags}; <span class="doccomment">/// A simple `mmap`ed runtime with executable pages. </span><span class="kw">pub struct </span>Runtime { buf: <span class="kw-2">*mut </span>c_void, len: usize, } <span class="kw">impl </span>Runtime { <span class="doccomment">/// Create a new [Runtime]. </span><span class="kw">pub fn </span>new(code: <span class="kw">impl </span>AsRef<[u8]>) -> Runtime { <span class="comment">// Allocate a single page. </span><span class="kw">let </span>len = core::num::NonZeroUsize::new(<span class="number">4096</span>).unwrap(); <span class="kw">let </span>buf = <span class="kw">unsafe </span>{ mmap( <span class="prelude-val">None</span>, len, ProtFlags::PROT_WRITE | ProtFlags::PROT_READ | ProtFlags::PROT_EXEC, MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS, <span class="number">0</span>, <span class="comment">/* fd */ </span><span class="number">0</span>, <span class="comment">/* off */ </span>) .unwrap() }; { <span class="comment">// Copy over code. </span><span class="kw">let </span>code = code.as_ref(); <span class="macro">assert!</span>(code.len() < len.get()); <span class="kw">unsafe </span>{ std::ptr::copy_nonoverlapping(code.as_ptr(), buf.cast(), len.get()) }; } Runtime { buf, len: len.get(), } } <span class="doccomment">/// Reinterpret the block of code as `F`. </span><span class="attr">#[inline] </span><span class="kw">pub unsafe fn </span>as_fn<F>(<span class="kw-2">&</span><span class="self">self</span>) -> F { <span class="kw">unsafe </span>{ std::mem::transmute_copy(<span class="kw-2">&</span><span class="self">self</span>.buf) } } } <span class="kw">impl </span>Drop <span class="kw">for </span>Runtime { <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { <span class="kw">unsafe </span>{ munmap(<span class="self">self</span>.buf, <span class="self">self</span>.len).expect(<span class="string">"Failed to munmap Runtime"</span>); } } } </code></pre></div> </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="juicebox_asm" data-themes="" data-resource-suffix="" data-rustdoc-version="1.67.1 (d5a82bbd2 2023-02-07)" data-search-js="search-444266647c4dba98.js" data-settings-js="settings-bebeae96e00e4617.js" data-settings-css="settings-af96d9e2fc13e081.css" ></div></body></html>