464 lines
30 KiB
HTML
464 lines
30 KiB
HTML
<!DOCTYPE HTML>
|
||
<html lang="en" class="light sidebar-visible" dir="ltr">
|
||
<head>
|
||
<!-- Book generated using mdBook -->
|
||
<meta charset="UTF-8">
|
||
<title>Rustdoc internals - Rust Compiler Development Guide</title>
|
||
|
||
|
||
<!-- Custom HTML head -->
|
||
|
||
<meta name="description" content="A guide to developing the Rust compiler (rustc)">
|
||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||
<meta name="theme-color" content="#ffffff">
|
||
|
||
<link rel="icon" href="favicon.svg">
|
||
<link rel="shortcut icon" href="favicon.png">
|
||
<link rel="stylesheet" href="css/variables.css">
|
||
<link rel="stylesheet" href="css/general.css">
|
||
<link rel="stylesheet" href="css/chrome.css">
|
||
<link rel="stylesheet" href="css/print.css" media="print">
|
||
|
||
<!-- Fonts -->
|
||
<link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
|
||
<link rel="stylesheet" href="fonts/fonts.css">
|
||
|
||
<!-- Highlight.js Stylesheets -->
|
||
<link rel="stylesheet" id="highlight-css" href="highlight.css">
|
||
<link rel="stylesheet" id="tomorrow-night-css" href="tomorrow-night.css">
|
||
<link rel="stylesheet" id="ayu-highlight-css" href="ayu-highlight.css">
|
||
|
||
<!-- Custom theme stylesheets -->
|
||
|
||
|
||
<!-- Provide site root and default themes to javascript -->
|
||
<script>
|
||
const path_to_root = "";
|
||
const default_light_theme = "light";
|
||
const default_dark_theme = "navy";
|
||
</script>
|
||
<!-- Start loading toc.js asap -->
|
||
<script src="toc.js"></script>
|
||
</head>
|
||
<body>
|
||
<div id="body-container">
|
||
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
||
<script>
|
||
try {
|
||
let theme = localStorage.getItem('mdbook-theme');
|
||
let sidebar = localStorage.getItem('mdbook-sidebar');
|
||
|
||
if (theme.startsWith('"') && theme.endsWith('"')) {
|
||
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
||
}
|
||
|
||
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
||
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
||
}
|
||
} catch (e) { }
|
||
</script>
|
||
|
||
<!-- Set the theme before any content is loaded, prevents flash -->
|
||
<script>
|
||
const default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? default_dark_theme : default_light_theme;
|
||
let theme;
|
||
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
||
if (theme === null || theme === undefined) { theme = default_theme; }
|
||
const html = document.documentElement;
|
||
html.classList.remove('light')
|
||
html.classList.add(theme);
|
||
html.classList.add("js");
|
||
</script>
|
||
|
||
<input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
|
||
|
||
<!-- Hide / unhide sidebar before it is displayed -->
|
||
<script>
|
||
let sidebar = null;
|
||
const sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
|
||
if (document.body.clientWidth >= 1080) {
|
||
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
||
sidebar = sidebar || 'visible';
|
||
} else {
|
||
sidebar = 'hidden';
|
||
}
|
||
sidebar_toggle.checked = sidebar === 'visible';
|
||
html.classList.remove('sidebar-visible');
|
||
html.classList.add("sidebar-" + sidebar);
|
||
</script>
|
||
|
||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||
<!-- populated by js -->
|
||
<mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
|
||
<noscript>
|
||
<iframe class="sidebar-iframe-outer" src="toc.html"></iframe>
|
||
</noscript>
|
||
<div id="sidebar-resize-handle" class="sidebar-resize-handle">
|
||
<div class="sidebar-resize-indicator"></div>
|
||
</div>
|
||
</nav>
|
||
|
||
<div id="page-wrapper" class="page-wrapper">
|
||
|
||
<div class="page">
|
||
<div id="menu-bar-hover-placeholder"></div>
|
||
<div id="menu-bar" class="menu-bar sticky">
|
||
<div class="left-buttons">
|
||
<label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
||
<i class="fa fa-bars"></i>
|
||
</label>
|
||
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
||
<i class="fa fa-paint-brush"></i>
|
||
</button>
|
||
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
||
<li role="none"><button role="menuitem" class="theme" id="default_theme">Auto</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
||
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
||
</ul>
|
||
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
||
<i class="fa fa-search"></i>
|
||
</button>
|
||
</div>
|
||
|
||
<h1 class="menu-title">Rust Compiler Development Guide</h1>
|
||
|
||
<div class="right-buttons">
|
||
<a href="print.html" title="Print this book" aria-label="Print this book">
|
||
<i id="print-button" class="fa fa-print"></i>
|
||
</a>
|
||
<a href="https://github.com/rust-lang/rustc-dev-guide" title="Git repository" aria-label="Git repository">
|
||
<i id="git-repository-button" class="fa fa-github"></i>
|
||
</a>
|
||
<a href="https://github.com/rust-lang/rustc-dev-guide/edit/master/src/rustdoc-internals.md" title="Suggest an edit" aria-label="Suggest an edit">
|
||
<i id="git-edit-button" class="fa fa-edit"></i>
|
||
</a>
|
||
|
||
</div>
|
||
</div>
|
||
|
||
<div id="search-wrapper" class="hidden">
|
||
<form id="searchbar-outer" class="searchbar-outer">
|
||
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
||
</form>
|
||
<div id="searchresults-outer" class="searchresults-outer hidden">
|
||
<div id="searchresults-header" class="searchresults-header"></div>
|
||
<ul id="searchresults">
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
|
||
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
||
<script>
|
||
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
||
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
||
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
||
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
||
});
|
||
</script>
|
||
|
||
<div id="content" class="content">
|
||
<main>
|
||
<h1 id="rustdoc-internals"><a class="header" href="#rustdoc-internals">Rustdoc Internals</a></h1>
|
||
<ul>
|
||
<li><a href="#from-crate-to-clean">From Crate to Clean</a>
|
||
<ul>
|
||
<li><a href="#passes-anything-but-a-gas-station-or-hot-potato">Passes Anything But a Gas Station (or: Hot Potato)</a></li>
|
||
</ul>
|
||
</li>
|
||
<li><a href="#from-clean-to-html">From Clean To HTML</a>
|
||
<ul>
|
||
<li><a href="#from-soup-to-nuts-or-an-unbroken-thread-stretches-from-those-first-cells-to-us">From Soup to Nuts (or: "An Unbroken Thread Stretches From Those First <code>Cell</code>s To Us")</a></li>
|
||
</ul>
|
||
</li>
|
||
<li><a href="#other-tricks-up-its-sleeve">Other Tricks Up Its Sleeve</a></li>
|
||
<li><a href="#testing-locally">Testing Locally</a></li>
|
||
<li><a href="#see-also">See Also</a></li>
|
||
</ul>
|
||
<p>This page describes <a href="https://github.com/rust-lang/rust/tree/master/src/tools/rustdoc"><code>rustdoc</code></a>'s passes and modes. For an overview of <code>rustdoc</code>,
|
||
see the <a href="./rustdoc.html">"Rustdoc overview" chapter</a>.</p>
|
||
<h2 id="from-crate-to-clean"><a class="header" href="#from-crate-to-clean">From Crate to Clean</a></h2>
|
||
<p>In <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/core.rs"><code>core.rs</code></a> are two central items: the <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/core/struct.DocContext.html"><code>rustdoc::core::DocContext</code></a>
|
||
<code>struct</code>, and the <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/core/fn.run_global_ctxt.html"><code>rustdoc::core::run_global_ctxt</code></a> function. The latter is
|
||
where <code>rustdoc</code> calls out to <code>rustc</code> to compile a crate to the point where
|
||
<code>rustdoc</code> can take over. The former is a state container used when crawling
|
||
through a crate to gather its documentation.</p>
|
||
<p>The main process of crate crawling is done in <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/clean/mod.rs"><code>clean/mod.rs</code></a> through several
|
||
functions with names that start with <code>clean_</code>. Each function accepts an <code>hir</code>
|
||
or <code>ty</code> data structure, and outputs a <code>clean</code> structure used by <code>rustdoc</code>. For
|
||
example, <a href="https://doc.rust-lang.org/nightly/nightly-rustc/src/rustdoc/clean/mod.rs.html#256-267">this function for converting lifetimes</a>:</p>
|
||
<pre><code class="language-rust ignore">fn clean_lifetime<'tcx>(lifetime: &hir::Lifetime, cx: &mut DocContext<'tcx>) -> Lifetime {
|
||
if let Some(
|
||
rbv::ResolvedArg::EarlyBound(did)
|
||
| rbv::ResolvedArg::LateBound(_, _, did)
|
||
| rbv::ResolvedArg::Free(_, did),
|
||
) = cx.tcx.named_bound_var(lifetime.hir_id)
|
||
&& let Some(lt) = cx.args.get(&did).and_then(|arg| arg.as_lt())
|
||
{
|
||
return lt.clone();
|
||
}
|
||
Lifetime(lifetime.ident.name)
|
||
}</code></pre>
|
||
<p>Also, <code>clean/mod.rs</code> defines the types for the "cleaned" <a href="./ast-validation.html">Abstract Syntax Tree
|
||
(<code>AST</code>)</a> used later to render documentation pages. Each usually accompanies a
|
||
<code>clean_*</code> function that takes some <a href="./ast-validation.html"><code>AST</code></a> or <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/index.html">High-Level Intermediate
|
||
Representation (<code>HIR</code>)</a> type from <code>rustc</code> and converts it into the
|
||
appropriate "cleaned" type. "Big" items like modules or associated items may
|
||
have some extra processing in its <code>clean</code> function, but for the most part these
|
||
<code>impl</code>s are straightforward conversions. The "entry point" to this module is
|
||
<a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/clean/utils/fn.krate.html#"><code>clean::utils::krate</code></a>, which is called by <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/core/fn.run_global_ctxt.html"><code>run_global_ctxt</code></a>.</p>
|
||
<p>The first step in <a href="https://doc.rust-lang.org/nightly/nightly-rustc/src/rustdoc/clean/utils.rs.html#31-77"><code>clean::utils::krate</code></a> is to invoke
|
||
<a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/visit_ast/struct.RustdocVisitor.html"><code>visit_ast::RustdocVisitor</code></a> to process the module tree into an intermediate
|
||
<a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/visit_ast/struct.Module.html"><code>visit_ast::Module</code></a>. This is the step that actually crawls the
|
||
<a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/hir/struct.Crate.html"><code>rustc_hir::Crate</code></a>, normalizing various aspects of name resolution, such as:</p>
|
||
<ul>
|
||
<li>handling <code>#[doc(inline)]</code> and <code>#[doc(no_inline)]</code></li>
|
||
<li>handling import globs and cycles, so there are no duplicates or infinite
|
||
directory trees</li>
|
||
<li>inlining public <code>use</code> exports of private items, or showing a "Reexport"
|
||
line in the module page</li>
|
||
<li>inlining items with <code>#[doc(hidden)]</code> if the base item is hidden but the</li>
|
||
<li>showing <code>#[macro_export]</code>-ed macros at the crate root, regardless of whether
|
||
they're defined as a reexport or not</li>
|
||
</ul>
|
||
<p>After this step, <code>clean::krate</code> invokes <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/clean/fn.clean_doc_module.html"><code>clean_doc_module</code></a>, which actually
|
||
converts the <code>HIR</code> items to the cleaned <a href="./ast-validation.html"><code>AST</code></a>. This is also the step where cross-
|
||
crate inlining is performed, which requires converting <code>rustc_middle</code> data
|
||
structures into the cleaned <a href="./ast-validation.html"><code>AST</code></a>.</p>
|
||
<p>The other major thing that happens in <code>clean/mod.rs</code> is the collection of doc
|
||
comments and <code>#[doc=""]</code> attributes into a separate field of the <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/clean/types/struct.Attributes.html"><code>Attributes</code></a>
|
||
<code>struct</code>, present on anything that gets hand-written documentation. This makes it
|
||
easier to collect this documentation later in the process.</p>
|
||
<p>The primary output of this process is a <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/clean/types/struct.Crate.html"><code>clean::types::Crate</code></a> with a tree of <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/clean/types/struct.Item.html"><code>Item</code></a>s
|
||
which describe the publicly-documentable items in the target crate.</p>
|
||
<h3 id="passes-anything-but-a-gas-station-or-hot-potato"><a class="header" href="#passes-anything-but-a-gas-station-or-hot-potato">Passes Anything But a Gas Station (or: <a href="https://www.youtube.com/watch?v=WNFBIt5HxdY">Hot Potato</a>)</a></h3>
|
||
<p>Before moving on to the next major step, a few important "passes" occur over
|
||
the cleaned <a href="./ast-validation.html"><code>AST</code></a>. Several of these passes are <code>lint</code>s and reports, but some of
|
||
them mutate or generate new items.</p>
|
||
<p>These are all implemented in the <a href="https://github.com/rust-lang/rust/tree/master/src/librustdoc/passes"><code>librustdoc/passes</code></a> directory, one file per pass.
|
||
By default, all of these passes are run on a crate, but the ones
|
||
regarding dropping private/hidden items can be bypassed by passing
|
||
<code>--document-private-items</code> to <code>rustdoc</code>. Note that unlike the previous set of <a href="./ast-validation.html"><code>AST</code></a>
|
||
transformations, the passes are run on the <em>cleaned</em> crate.</p>
|
||
<p>Here is the list of passes as of <!-- date-check --> March 2023:</p>
|
||
<ul>
|
||
<li>
|
||
<p><code>calculate-doc-coverage</code> calculates information used for the <code>--show-coverage</code>
|
||
flag.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>check-doc-test-visibility</code> runs <code>doctest</code> visibility–related <code>lint</code>s. This pass
|
||
runs before <code>strip-private</code>, which is why it needs to be separate from
|
||
<code>run-lints</code>.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>collect-intra-doc-links</code> resolves <a href="https://doc.rust-lang.org/nightly/rustdoc/write-documentation/linking-to-items-by-name.html">intra-doc links</a>.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>collect-trait-impls</code> collects <code>trait</code> <code>impl</code>s for each item in the crate. For
|
||
example, if we define a <code>struct</code> that implements a <code>trait</code>, this pass will note
|
||
that the <code>struct</code> implements that <code>trait</code>.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>propagate-doc-cfg</code> propagates <code>#[doc(cfg(...))]</code> to child items.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>run-lints</code> runs some of <code>rustdoc</code>'s <code>lint</code>s, defined in <code>passes/lint</code>. This is
|
||
the last pass to run.</p>
|
||
<ul>
|
||
<li>
|
||
<p><code>bare_urls</code> detects links that are not linkified, e.g., in Markdown such as
|
||
<code>Go to https://example.com/.</code> It suggests wrapping the link with angle brackets:
|
||
<code>Go to <https://example.com/>.</code> to linkify it. This is the code behind the <!--
|
||
date-check: may 2022 --> <code>rustdoc::bare_urls</code> <code>lint</code>.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>check_code_block_syntax</code> validates syntax inside Rust code blocks
|
||
(<code>```rust</code>)</p>
|
||
</li>
|
||
<li>
|
||
<p><code>html_tags</code> detects invalid <code>HTML</code> (like an unclosed <code><span></code>)
|
||
in doc comments.</p>
|
||
</li>
|
||
</ul>
|
||
</li>
|
||
<li>
|
||
<p><code>strip-hidden</code> and <code>strip-private</code> strip all <code>doc(hidden)</code> and private items
|
||
from the output. <code>strip-private</code> implies <code>strip-priv-imports</code>. Basically, the
|
||
goal is to remove items that are not relevant for public documentation. This
|
||
pass is skipped when <code>--document-hidden-items</code> is passed.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>strip-priv-imports</code> strips all private import statements (<code>use</code>, <code>extern crate</code>) from a crate. This is necessary because <code>rustdoc</code> will handle <em>public</em>
|
||
imports by either inlining the item's documentation to the module or creating
|
||
a "Reexports" section with the import in it. The pass ensures that all of
|
||
these imports are actually relevant to documentation. It is technically
|
||
only run when <code>--document-private-items</code> is passed, but <code>strip-private</code>
|
||
accomplishes the same thing.</p>
|
||
</li>
|
||
<li>
|
||
<p><code>strip-private</code> strips all private items from a crate which cannot be seen
|
||
externally. This pass is skipped when <code>--document-private-items</code> is passed.</p>
|
||
</li>
|
||
</ul>
|
||
<p>There is also a <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/passes/stripper/index.html"><code>stripper</code></a> module in <code>librustdoc/passes</code>, but it is a
|
||
collection of utility functions for the <code>strip-*</code> passes and is not a pass
|
||
itself.</p>
|
||
<h2 id="from-clean-to-html"><a class="header" href="#from-clean-to-html">From Clean To HTML</a></h2>
|
||
<p>This is where the "second phase" in <code>rustdoc</code> begins. This phase primarily lives
|
||
in the <a href="https://github.com/rust-lang/rust/tree/master/src/librustdoc/formats"><code>librustdoc/formats</code></a> and <a href="https://github.com/rust-lang/rust/tree/master/src/librustdoc/html"><code>librustdoc/html</code></a> folders, and it all starts with
|
||
<a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/formats/renderer/fn.run_format.html"><code>formats::renderer::run_format</code></a>. This code is responsible for setting up a type that
|
||
<code>impl FormatRenderer</code>, which for <code>HTML</code> is <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/html/render/context/struct.Context.html"><code>Context</code></a>.</p>
|
||
<p>This structure contains methods that get called by <code>run_format</code> to drive the
|
||
doc rendering, which includes:</p>
|
||
<ul>
|
||
<li><code>init</code> generates <code>static.files</code>, as well as search index and <code>src/</code></li>
|
||
<li><code>item</code> generates the item <code>HTML</code> files themselves</li>
|
||
<li><code>after_krate</code> generates other global resources like <code>all.html</code></li>
|
||
</ul>
|
||
<p>In <code>item</code>, the "page rendering" occurs, via a mixture of <a href="https://docs.rs/askama/latest/askama/">Askama</a> templates
|
||
and manual <code>write!()</code> calls, starting in <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/layout.rs"><code>html/layout.rs</code></a>. The parts that have
|
||
not been converted to templates occur within a series of <code>std::fmt::Display</code>
|
||
implementations and functions that pass around a <code>&mut std::fmt::Formatter</code>.</p>
|
||
<p>The parts that actually generate <code>HTML</code> from the items and documentation start
|
||
with <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/html/render/print_item/fn.print_item.html"><code>print_item</code></a> defined in <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/render/print_item.rs"><code>html/render/print_item.rs</code></a>, which switches out
|
||
to one of several <code>item_*</code> functions based on kind of <code>Item</code> being rendered.</p>
|
||
<p>Depending on what kind of rendering code you're looking for, you'll probably
|
||
find it either in <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/render/mod.rs"><code>html/render/mod.rs</code></a> for major items like "what sections
|
||
should I print for a <code>struct</code> page" or <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/format.rs"><code>html/format.rs</code></a> for smaller component
|
||
pieces like "how should I print a where clause as part of some other item".</p>
|
||
<p>Whenever <code>rustdoc</code> comes across an item that should print hand-written
|
||
documentation alongside, it calls out to <a href="https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/markdown.rs"><code>html/markdown.rs</code></a> which interfaces
|
||
with the Markdown parser. This is exposed as a series of types that wrap a
|
||
string of Markdown, and implement <code>fmt::Display</code> to emit <code>HTML</code> text. It takes
|
||
special care to enable certain features like footnotes and tables and add
|
||
syntax highlighting to Rust code blocks (via <code>html/highlight.rs</code>) before
|
||
running the Markdown parser. There's also a function <a href="https://doc.rust-lang.org/nightly/nightly-rustc/src/rustdoc/html/markdown.rs.html#749-818"><code>find_codes</code></a> which is
|
||
called by <code>find_testable_codes</code> that specifically scans for Rust code blocks so
|
||
the test-runner code can find all the <code>doctest</code>s in the crate.</p>
|
||
<h3 id="from-soup-to-nuts-or-an-unbroken-thread-stretches-from-those-first-cells-to-us"><a class="header" href="#from-soup-to-nuts-or-an-unbroken-thread-stretches-from-those-first-cells-to-us">From Soup to Nuts (or: <a href="https://www.youtube.com/watch?v=hOLAGYmUQV0">"An Unbroken Thread Stretches From Those First <code>Cell</code>s To Us"</a>)</a></h3>
|
||
<p>It's important to note that <code>rustdoc</code> can ask the compiler for type information
|
||
directly, even during <code>HTML</code> generation. This <a href="https://github.com/rust-lang/rust/pull/80090">didn't used to be the case</a>, and
|
||
a lot of <code>rustdoc</code>'s architecture was designed around not doing that, but a
|
||
<code>TyCtxt</code> is now passed to <code>formats::renderer::run_format</code>, which is used to
|
||
run generation for both <code>HTML</code> and the
|
||
(unstable as of <!-- date-check --> March 2023) JSON format.</p>
|
||
<p>This change has allowed other changes to remove data from the "clean" <a href="./ast-validation.html"><code>AST</code></a>
|
||
that can be easily derived from <code>TyCtxt</code> queries, and we'll usually accept
|
||
PRs that remove fields from "clean" (it's been soft-deprecated), but this
|
||
is complicated from two other constraints that <code>rustdoc</code> runs under:</p>
|
||
<ul>
|
||
<li>Docs can be generated for crates that don't actually pass type checking.
|
||
This is used for generating docs that cover mutually-exclusive platform
|
||
configurations, such as <code>libstd</code> having a single package of docs that
|
||
cover all supported operating systems. This means <code>rustdoc</code> has to be able
|
||
to generate docs from <code>HIR</code>.</li>
|
||
<li>Docs can inline across crates. Since crate metadata doesn't contain <code>HIR</code>,
|
||
it must be possible to generate inlined docs from the <code>rustc_middle</code> data.</li>
|
||
</ul>
|
||
<p>The "clean" <a href="./ast-validation.html"><code>AST</code></a> acts as a common output format for both input formats. There
|
||
is also some data in clean that doesn't correspond directly to <code>HIR</code>, such as
|
||
synthetic <code>impl</code>s for auto traits and blanket <code>impl</code>s generated by the
|
||
<code>collect-trait-impls</code> pass.</p>
|
||
<p>Some additional data is stored in
|
||
<code>html::render::context::{Context, SharedContext}</code>. These two types serve as
|
||
ways to segregate <code>rustdoc</code>'s data for an eventual future with multithreaded doc
|
||
generation, as well as just keeping things organized:</p>
|
||
<ul>
|
||
<li><a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/html/render/context/struct.Context.html"><code>Context</code></a> stores data used for generating the current page, such as its
|
||
path, a list of <code>HTML</code> IDs that have been used (to avoid duplicate <code>id=""</code>),
|
||
and the pointer to <code>SharedContext</code>.</li>
|
||
<li><a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/html/render/context/struct.SharedContext.html"><code>SharedContext</code></a> stores data that does not vary by page, such as the <code>tcx</code>
|
||
pointer, and a list of all types.</li>
|
||
</ul>
|
||
<h2 id="other-tricks-up-its-sleeve"><a class="header" href="#other-tricks-up-its-sleeve">Other Tricks Up Its Sleeve</a></h2>
|
||
<p>All this describes the process for generating <code>HTML</code> documentation from a Rust
|
||
crate, but there are couple other major modes that <code>rustdoc</code> runs in. It can also
|
||
be run on a standalone Markdown file, or it can run <code>doctest</code>s on Rust code or
|
||
standalone Markdown files. For the former, it shortcuts straight to
|
||
<code>html/markdown.rs</code>, optionally including a mode which inserts a Table of
|
||
Contents to the output <code>HTML</code>.</p>
|
||
<p>For the latter, <code>rustdoc</code> runs a similar partial-compilation to get relevant
|
||
documentation in <code>test.rs</code>, but instead of going through the full clean and
|
||
render process, it runs a much simpler crate walk to grab <em>just</em> the
|
||
hand-written documentation. Combined with the aforementioned
|
||
"<code>find_testable_code</code>" in <code>html/markdown.rs</code>, it builds up a collection of
|
||
tests to run before handing them off to the test runner. One notable location
|
||
in <code>test.rs</code> is the function <code>make_test</code>, which is where hand-written
|
||
<code>doctest</code>s get transformed into something that can be executed.</p>
|
||
<p>Some extra reading about <code>make_test</code> can be found
|
||
<a href="https://quietmisdreavus.net/code/2018/02/23/how-the-doctests-get-made/">here</a>.</p>
|
||
<h2 id="testing-locally"><a class="header" href="#testing-locally">Testing Locally</a></h2>
|
||
<p>Some features of the generated <code>HTML</code> documentation might require local
|
||
storage to be used across pages, which doesn't work well without an <code>HTTP</code>
|
||
server. To test these features locally, you can run a local <code>HTTP</code> server, like
|
||
this:</p>
|
||
<pre><code class="language-bash">$ ./x doc library
|
||
# The documentation has been generated into `build/[YOUR ARCH]/doc`.
|
||
$ python3 -m http.server -d build/[YOUR ARCH]/doc
|
||
</code></pre>
|
||
<p>Now you can browse your documentation just like you would if it was hosted
|
||
on the internet. For example, the url for <code>std</code> will be <code>rust/std/</code>.</p>
|
||
<h2 id="see-also"><a class="header" href="#see-also">See Also</a></h2>
|
||
<ul>
|
||
<li>The <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/"><code>rustdoc</code> api docs</a></li>
|
||
<li><a href="./rustdoc.html">An overview of <code>rustdoc</code></a></li>
|
||
<li><a href="https://doc.rust-lang.org/nightly/rustdoc/">The rustdoc user guide</a></li>
|
||
</ul>
|
||
|
||
</main>
|
||
|
||
<nav class="nav-wrapper" aria-label="Page navigation">
|
||
<!-- Mobile navigation buttons -->
|
||
<a rel="prev" href="parallel-rustc.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
||
<i class="fa fa-angle-left"></i>
|
||
</a>
|
||
|
||
<a rel="next prefetch" href="rustdoc-internals/search.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||
<i class="fa fa-angle-right"></i>
|
||
</a>
|
||
|
||
<div style="clear: both"></div>
|
||
</nav>
|
||
</div>
|
||
</div>
|
||
|
||
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
||
<a rel="prev" href="parallel-rustc.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
||
<i class="fa fa-angle-left"></i>
|
||
</a>
|
||
|
||
<a rel="next prefetch" href="rustdoc-internals/search.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||
<i class="fa fa-angle-right"></i>
|
||
</a>
|
||
</nav>
|
||
|
||
</div>
|
||
|
||
|
||
|
||
|
||
<script>
|
||
window.playground_copyable = true;
|
||
</script>
|
||
|
||
|
||
<script src="elasticlunr.min.js"></script>
|
||
<script src="mark.min.js"></script>
|
||
<script src="searcher.js"></script>
|
||
|
||
<script src="clipboard.min.js"></script>
|
||
<script src="highlight.js"></script>
|
||
<script src="book.js"></script>
|
||
|
||
<!-- Custom JS scripts -->
|
||
<script src="mermaid.min.js"></script>
|
||
<script src="mermaid-init.js"></script>
|
||
|
||
|
||
</div>
|
||
</body>
|
||
</html>
|