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| <ol class="chapter"><li class="chapter-item affix "><a href="about-this-guide.html">About this guide</a></li><li class="chapter-item affix "><a href="getting-started.html">Getting Started</a></li><li class="spacer"></li><li class="chapter-item affix "><li class="part-title">Building and debugging rustc</li><li class="chapter-item "><a href="building/how-to-build-and-run.html"><strong aria-hidden="true">1.</strong> How to Build and Run the Compiler</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="building/prerequisites.html"><strong aria-hidden="true">1.1.</strong> Prerequisites</a></li><li class="chapter-item "><a href="building/suggested.html"><strong aria-hidden="true">1.2.</strong> Suggested Workflows</a></li><li class="chapter-item "><a href="building/build-install-distribution-artifacts.html"><strong aria-hidden="true">1.3.</strong> Distribution artifacts</a></li><li class="chapter-item "><a href="building/compiler-documenting.html"><strong aria-hidden="true">1.4.</strong> Documenting Compiler</a></li><li class="chapter-item "><a href="rustdoc.html"><strong aria-hidden="true">1.5.</strong> Rustdoc overview</a></li><li class="chapter-item "><a href="building/new-target.html"><strong aria-hidden="true">1.6.</strong> Adding a new target</a></li></ol></li><li class="chapter-item "><a href="tests/intro.html"><strong aria-hidden="true">2.</strong> The compiler testing framework</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="tests/running.html"><strong aria-hidden="true">2.1.</strong> Running tests</a></li><li class="chapter-item "><a href="tests/adding.html"><strong aria-hidden="true">2.2.</strong> Adding new tests</a></li><li class="chapter-item "><a href="compiletest.html"><strong aria-hidden="true">2.3.</strong> Using compiletest commands to control test execution</a></li></ol></li><li class="chapter-item "><a href="compiler-debugging.html"><strong aria-hidden="true">3.</strong> Debugging the Compiler</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="tracing.html"><strong aria-hidden="true">3.1.</strong> Using the tracing/logging instrumentation</a></li></ol></li><li class="chapter-item "><a href="profiling.html"><strong aria-hidden="true">4.</strong> Profiling the compiler</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="profiling/with_perf.html"><strong aria-hidden="true">4.1.</strong> with the linux perf tool</a></li><li class="chapter-item "><a href="profiling/wpa_profiling.html"><strong aria-hidden="true">4.2.</strong> with Windows Performance Analyzer</a></li></ol></li><li class="chapter-item "><a href="crates-io.html"><strong aria-hidden="true">5.</strong> crates.io Dependencies</a></li><li class="chapter-item affix "><li class="part-title">Contributing to Rust</li><li class="chapter-item "><a href="contributing.html"><strong aria-hidden="true">6.</strong> Introduction</a></li><li class="chapter-item "><a href="compiler-team.html"><strong aria-hidden="true">7.</strong> About the compiler team</a></li><li class="chapter-item "><a href="git.html"><strong aria-hidden="true">8.</strong> Using Git</a></li><li class="chapter-item "><a href="rustbot.html"><strong aria-hidden="true">9.</strong> Mastering @rustbot</a></li><li class="chapter-item "><a href="walkthrough.html"><strong aria-hidden="true">10.</strong> Walkthrough: a typical contribution</a></li><li class="chapter-item "><a href="bug-fix-procedure.html"><strong aria-hidden="true">11.</strong> Bug Fix Procedure</a></li><li class="chapter-item "><a href="implementing_new_features.html"><strong aria-hidden="true">12.</strong> Implementing new features</a></li><li class="chapter-item "><a href="stability.html"><strong aria-hidden="true">13.</strong> Stability attributes</a></li><li class="chapter-item "><a href="stabilization_guide.html"><strong aria-hidden="true">14.</strong> Stabilizing Features</a></li><li class="chapter-item "><a href="feature-gates.html"><strong aria-hidden="true">15.</strong> Feature Gates</a></li><li class="chapter-item "><a href="conventions.html"><strong aria-hidden="true">16.</strong> Coding conventions</a></li><li class="chapter-item "><a href="notification-groups/about.html"><strong aria-hidden="true">17.</strong> Notification groups</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="notification-groups/arm.html"><strong aria-hidden="true">17.1.</strong> ARM</a></li><li class="chapter-item "><a href="notification-groups/cleanup-crew.html"><strong aria-hidden="true">17.2.</strong> Cleanup Crew</a></li><li class="chapter-item "><a href="notification-groups/llvm.html"><strong aria-hidden="true">17.3.</strong> LLVM</a></li><li class="chapter-item "><a href="notification-groups/risc-v.html"><strong aria-hidden="true">17.4.</strong> RISC-V</a></li><li class="chapter-item "><a href="notification-groups/windows.html"><strong aria-hidden="true">17.5.</strong> Windows</a></li></ol></li><li class="chapter-item "><a href="licenses.html"><strong aria-hidden="true">18.</strong> Licenses</a></li><li class="chapter-item affix "><li class="part-title">High-level Compiler Architecture</li><li class="chapter-item "><a href="part-2-intro.html"><strong aria-hidden="true">19.</strong> Prologue</a></li><li class="chapter-item "><a href="overview.html"><strong aria-hidden="true">20.</strong> Overview of the Compiler</a></li><li class="chapter-item "><a href="compiler-src.html"><strong aria-hidden="true">21.</strong> The compiler source code</a></li><li class="chapter-item "><a href="building/bootstrapping.html"><strong aria-hidden="true">22.</strong> Bootstrapping</a></li><li class="chapter-item "><a href="query.html"><strong aria-hidden="true">23.</strong> Queries: demand-driven compilation</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="queries/query-evaluation-model-in-detail.html"><strong aria-hidden="true">23.1.</strong> The Query Evaluation Model in Detail</a></li><li class="chapter-item "><a href="queries/incremental-compilation.html"><strong aria-hidden="true">23.2.</strong> Incremental compilation</a></li><li class="chapter-item "><a href="queries/incremental-compilation-in-detail.html"><strong aria-hidden="true">23.3.</strong> Incremental compilation In Detail</a></li><li class="chapter-item "><a href="incrcomp-debugging.html"><strong aria-hidden="true">23.4.</strong> Debugging and Testing</a></li><li class="chapter-item "><a href="salsa.html"><strong aria-hidden="true">23.5.</strong> Salsa</a></li></ol></li><li class="chapter-item "><a href="memory.html"><strong aria-hidden="true">24.</strong> Memory Management in Rustc</a></li><li class="chapter-item "><a href="serialization.html"><strong aria-hidden="true">25.</strong> Serialization in Rustc</a></li><li class="chapter-item "><a href="parallel-rustc.html"><strong aria-hidden="true">26.</strong> Parallel Compilation</a></li><li class="chapter-item expanded "><a href="rustdoc-internals.html" class="active"><strong aria-hidden="true">27.</strong> Rustdoc internals</a></li><li class="chapter-item affix "><li class="part-title">Source Code Representation</li><li class="chapter-item "><a href="part-3-intro.html"><strong aria-hidden="true">28.</strong> Prologue</a></li><li class="chapter-item "><a href="cli.html"><strong aria-hidden="true">29.</strong> Command-line arguments</a></li><li class="chapter-item "><a href="rustc-driver.html"><strong aria-hidden="true">30.</strong> The Rustc Driver and Interface</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="rustc-driver-interacting-with-the-ast.html"><strong aria-hidden="true">30.1.</strong> Ex: Type checking through rustc_interface</a></li><li class="chapter-item "><a href="rustc-driver-getting-diagnostics.html"><strong aria-hidden="true">30.2.</strong> Ex: Getting diagnostics through rustc_interface</a></li></ol></li><li class="chapter-item "><a href="syntax-intro.html"><strong aria-hidden="true">31.</strong> Syntax and the AST</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="the-parser.html"><strong aria-hidden="true">31.1.</strong> Lexing and Parsing</a></li><li class="chapter-item "><a href="macro-expansion.html"><strong aria-hidden="true">31.2.</strong> Macro expansion</a></li><li class="chapter-item "><a href="name-resolution.html"><strong aria-hidden="true">31.3.</strong> Name resolution</a></li><li class="chapter-item "><a href="test-implementation.html"><strong aria-hidden="true">31.4.</strong> #[test] Implementation</a></li><li class="chapter-item "><a href="panic-implementation.html"><strong aria-hidden="true">31.5.</strong> Panic Implementation</a></li><li class="chapter-item "><a href="ast-validation.html"><strong aria-hidden="true">31.6.</strong> AST Validation</a></li><li class="chapter-item "><a href="feature-gate-ck.html"><strong aria-hidden="true">31.7.</strong> Feature Gate Checking</a></li><li class="chapter-item "><a href="lang-items.html"><strong aria-hidden="true">31.8.</strong> Lang Items</a></li></ol></li><li class="chapter-item "><a href="hir.html"><strong aria-hidden="true">32.</strong> The HIR (High-level IR)</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="lowering.html"><strong aria-hidden="true">32.1.</strong> Lowering AST to HIR</a></li><li class="chapter-item "><a href="hir-debugging.html"><strong aria-hidden="true">32.2.</strong> Debugging</a></li></ol></li><li class="chapter-item "><a href="thir.html"><strong aria-hidden="true">33.</strong> The THIR (Typed High-level IR)</a></li><li class="chapter-item "><a href="mir/index.html"><strong aria-hidden="true">34.</strong> The MIR (Mid-level IR)</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="mir/construction.html"><strong aria-hidden="true">34.1.</strong> MIR construction</a></li><li class="chapter-item "><a href="mir/visitor.html"><strong aria-hidden="true">34.2.</strong> MIR visitor and traversal</a></li><li class="chapter-item "><a href="mir/passes.html"><strong aria-hidden="true">34.3.</strong> MIR passes: getting the MIR for a function</a></li></ol></li><li class="chapter-item "><a href="identifiers.html"><strong aria-hidden="true">35.</strong> Identifiers in the Compiler</a></li><li class="chapter-item "><a href="closure.html"><strong aria-hidden="true">36.</strong> Closure expansion</a></li><li class="chapter-item affix "><li class="part-title">Analysis</li><li class="chapter-item "><a href="part-4-intro.html"><strong aria-hidden="true">37.</strong> Prologue</a></li><li class="chapter-item "><a href="ty.html"><strong aria-hidden="true">38.</strong> The ty module: representing types</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="generics.html"><strong aria-hidden="true">38.1.</strong> Generics and substitutions</a></li><li class="chapter-item "><a href="ty-fold.html"><strong aria-hidden="true">38.2.</strong> TypeFolder and TypeFoldable</a></li><li class="chapter-item "><a href="generic_arguments.html"><strong aria-hidden="true">38.3.</strong> Generic arguments</a></li><li class="chapter-item "><a href="constants.html"><strong aria-hidden="true">38.4.</strong> Constants in the type system</a></li></ol></li><li class="chapter-item "><a href="type-inference.html"><strong aria-hidden="true">39.</strong> Type inference</a></li><li class="chapter-item "><a href="traits/resolution.html"><strong aria-hidden="true">40.</strong> Trait solving</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="early-late-bound.html"><strong aria-hidden="true">40.1.</strong> Early and Late Bound Parameters</a></li><li class="chapter-item "><a href="traits/hrtb.html"><strong aria-hidden="true">40.2.</strong> Higher-ranked trait bounds</a></li><li class="chapter-item "><a href="traits/caching.html"><strong aria-hidden="true">40.3.</strong> Caching subtleties</a></li><li class="chapter-item "><a href="traits/specialization.html"><strong aria-hidden="true">40.4.</strong> Specialization</a></li><li class="chapter-item "><a href="traits/chalk.html"><strong aria-hidden="true">40.5.</strong> Chalk-based trait solving</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="traits/lowering-to-logic.html"><strong aria-hidden="true">40.5.1.</strong> Lowering to logic</a></li><li class="chapter-item "><a href="traits/goals-and-clauses.html"><strong aria-hidden="true">40.5.2.</strong> Goals and clauses</a></li><li class="chapter-item "><a href="traits/canonical-queries.html"><strong aria-hidden="true">40.5.3.</strong> Canonical queries</a></li></ol></li></ol></li><li class="chapter-item "><a href="type-checking.html"><strong aria-hidden="true">41.</strong> Type checking</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="method-lookup.html"><strong aria-hidden="true">41.1.</strong> Method Lookup</a></li><li class="chapter-item "><a href="variance.html"><strong aria-hidden="true">41.2.</strong> Variance</a></li><li class="chapter-item "><a href="opaque-types-type-alias-impl-trait.html"><strong aria-hidden="true">41.3.</strong> Opaque Types</a></li></ol></li><li class="chapter-item "><a href="pat-exhaustive-checking.html"><strong aria-hidden="true">42.</strong> Pattern and Exhaustiveness Checking</a></li><li class="chapter-item "><a href="mir/dataflow.html"><strong aria-hidden="true">43.</strong> MIR dataflow</a></li><li class="chapter-item "><a href="borrow_check.html"><strong aria-hidden="true">44.</strong> The borrow checker</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="borrow_check/moves_and_initialization.html"><strong aria-hidden="true">44.1.</strong> Tracking moves and initialization</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="borrow_check/moves_and_initialization/move_paths.html"><strong aria-hidden="true">44.1.1.</strong> Move paths</a></li></ol></li><li class="chapter-item "><a href="borrow_check/type_check.html"><strong aria-hidden="true">44.2.</strong> MIR type checker</a></li><li class="chapter-item "><a href="borrow_check/region_inference.html"><strong aria-hidden="true">44.3.</strong> Region inference</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="borrow_check/region_inference/constraint_propagation.html"><strong aria-hidden="true">44.3.1.</strong> Constraint propagation</a></li><li class="chapter-item "><a href="borrow_check/region_inference/lifetime_parameters.html"><strong aria-hidden="true">44.3.2.</strong> Lifetime parameters</a></li><li class="chapter-item "><a href="borrow_check/region_inference/member_constraints.html"><strong aria-hidden="true">44.3.3.</strong> Member constraints</a></li><li class="chapter-item "><a href="borrow_check/region_inference/placeholders_and_universes.html"><strong aria-hidden="true">44.3.4.</strong> Placeholders and universes</a></li><li class="chapter-item "><a href="borrow_check/region_inference/closure_constraints.html"><strong aria-hidden="true">44.3.5.</strong> Closure constraints</a></li><li class="chapter-item "><a href="borrow_check/region_inference/error_reporting.html"><strong aria-hidden="true">44.3.6.</strong> Error reporting</a></li></ol></li><li class="chapter-item "><a href="borrow_check/two_phase_borrows.html"><strong aria-hidden="true">44.4.</strong> Two-phase-borrows</a></li></ol></li><li class="chapter-item "><a href="param_env.html"><strong aria-hidden="true">45.</strong> Parameter Environments</a></li><li class="chapter-item "><a href="diagnostics.html"><strong aria-hidden="true">46.</strong> Errors and Lints</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="diagnostics/sessiondiagnostic.html"><strong aria-hidden="true">46.1.</strong> Creating Errors With SessionDiagnostic</a></li><li class="chapter-item "><a href="diagnostics/lintstore.html"><strong aria-hidden="true">46.2.</strong> LintStore</a></li><li class="chapter-item "><a href="diagnostics/diagnostic-codes.html"><strong aria-hidden="true">46.3.</strong> Diagnostic Codes</a></li><li class="chapter-item "><a href="diagnostics/diagnostic-items.html"><strong aria-hidden="true">46.4.</strong> Diagnostic Items</a></li></ol></li><li class="chapter-item "><li class="part-title">MIR to Binaries</li><li class="chapter-item "><a href="part-5-intro.html"><strong aria-hidden="true">47.</strong> Prologue</a></li><li class="chapter-item "><a href="mir/optimizations.html"><strong aria-hidden="true">48.</strong> MIR optimizations</a></li><li class="chapter-item "><a href="mir/debugging.html"><strong aria-hidden="true">49.</strong> Debugging</a></li><li class="chapter-item "><a href="const-eval.html"><strong aria-hidden="true">50.</strong> Constant evaluation</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="miri.html"><strong aria-hidden="true">50.1.</strong> miri const evaluator</a></li></ol></li><li class="chapter-item "><a href="backend/monomorph.html"><strong aria-hidden="true">51.</strong> Monomorphization</a></li><li class="chapter-item "><a href="backend/lowering-mir.html"><strong aria-hidden="true">52.</strong> Lowering MIR</a></li><li class="chapter-item "><a href="backend/codegen.html"><strong aria-hidden="true">53.</strong> Code Generation</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="backend/updating-llvm.html"><strong aria-hidden="true">53.1.</strong> Updating LLVM</a></li><li class="chapter-item "><a href="backend/debugging.html"><strong aria-hidden="true">53.2.</strong> Debugging LLVM</a></li><li class="chapter-item "><a href="backend/backend-agnostic.html"><strong aria-hidden="true">53.3.</strong> Backend Agnostic Codegen</a></li><li class="chapter-item "><a href="backend/implicit-caller-location.html"><strong aria-hidden="true">53.4.</strong> Implicit Caller Location</a></li></ol></li><li class="chapter-item "><a href="backend/libs-and-metadata.html"><strong aria-hidden="true">54.</strong> Libraries and Metadata</a></li><li class="chapter-item "><a href="profile-guided-optimization.html"><strong aria-hidden="true">55.</strong> Profile-guided Optimization</a></li><li class="chapter-item "><a href="llvm-coverage-instrumentation.html"><strong aria-hidden="true">56.</strong> LLVM Source-Based Code Coverage</a></li><li class="chapter-item "><a href="sanitizers.html"><strong aria-hidden="true">57.</strong> Sanitizers Support</a></li><li class="chapter-item "><a href="debugging-support-in-rustc.html"><strong aria-hidden="true">58.</strong> Debugging Support in the Rust Compiler</a></li><li class="spacer"></li><li class="chapter-item affix "><a href="appendix/background.html">Appendix A: Background topics</a></li><li class="chapter-item affix "><a href="appendix/glossary.html">Appendix B: Glossary</a></li><li class="chapter-item affix "><a href="appendix/code-index.html">Appendix C: Code Index</a></li><li class="chapter-item affix "><a href="appendix/compiler-lecture.html">Appendix D: Compiler Lecture Series</a></li><li class="chapter-item affix "><a href="appendix/bibliography.html">Appendix E: Bibliography</a></li><li class="chapter-item affix "><a href="appendix/humorust.html">Appendix Z: HumorRust</a></li><li 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| <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="#hot-potato">Hot potato</a></li> |
| </ul> |
| </li> |
| <li><a href="#from-clean-to-crate">From clean to crate</a> |
| <ul> |
| <li><a href="#from-soup-to-nuts">From soup to nuts</a></li> |
| </ul> |
| </li> |
| <li><a href="#other-tricks-up-its-sleeve">Other tricks up its sleeve</a></li> |
| <li><a href="#dotting-is-and-crossing-ts">Dotting i's and crossing t's</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 rustdoc's passes and modes. For an overview of rustdoc, |
| 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 <code>core.rs</code> are two central items: the <code>DocContext</code> struct, and the <code>run_core</code> |
| function. The latter is where rustdoc calls out to rustc to compile a crate to |
| the point where rustdoc 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 <code>clean/mod.rs</code> through several |
| implementations of the <code>Clean</code> trait defined within. This is a conversion |
| trait, which defines one method:</p> |
| <pre><code class="language-rust ignore">pub trait Clean<T> { |
| fn clean(&self, cx: &DocContext) -> T; |
| } |
| </code></pre> |
| <p><code>clean/mod.rs</code> also defines the types for the "cleaned" AST used later on to |
| render documentation pages. Each usually accompanies an implementation of |
| <code>Clean</code> that takes some AST or HIR type from rustc 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> implementation, but for the most part |
| these impls are straightforward conversions. The "entry point" to this module |
| is the <code>impl Clean<Crate> for visit_ast::RustdocVisitor</code>, which is called by |
| <code>run_core</code> above.</p> |
| <p>You see, I actually lied a little earlier: There's another AST transformation |
| that happens before the events in <code>clean/mod.rs</code>. In <code>visit_ast.rs</code> is the |
| type <code>RustdocVisitor</code>, which <em>actually</em> crawls a <code>rustc_hir::Crate</code> to get the first |
| intermediate representation, defined in <code>doctree.rs</code>. This pass is mainly to |
| get a few intermediate wrappers around the HIR types and to process visibility |
| and inlining. This is where <code>#[doc(inline)]</code>, <code>#[doc(no_inline)]</code>, and |
| <code>#[doc(hidden)]</code> are processed, as well as the logic for whether a <code>pub use</code> |
| should get the full page or a "Reexport" line in the module page.</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 Attributes |
| struct, 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 <code>clean::Crate</code> with a tree of Items |
| which describe the publicly-documentable items in the target crate.</p> |
| <h3 id="hot-potato"><a class="header" href="#hot-potato">Hot potato</a></h3> |
| <p>Before moving on to the next major step, a few important "passes" occur over |
| the documentation. These do things like combine the separate "attributes" into |
| a single string and strip leading whitespace to make the document easier on the |
| markdown parser, or drop items that are not public or deliberately hidden with |
| <code>#[doc(hidden)]</code>. These are all implemented in the <code>passes/</code> 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 rustdoc. Note that unlike the previous set of AST |
| transformations, the passes are run on the <em>cleaned</em> crate.</p> |
| <p>(Strictly speaking, you can fine-tune the passes run and even add your own, but |
| <a href="https://github.com/rust-lang/rust/issues/44136">we're trying to deprecate that</a>. If you need finer-grain control over |
| these passes, please let us know!)</p> |
| <p>Here is the list of passes as of <!-- date: 2021-10 --> October 2021:</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-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</p> |
| <!-- date: 2021-10 --> `rustdoc::bare_urls` lint. |
| </li> |
| <li> |
| <p><code>check-code-block-syntax</code> validates syntax inside Rust code blocks |
| (<code>```rust</code>)</p> |
| </li> |
| <li> |
| <p><code>check-doc-test-visibility</code> runs doctest visibility–related lints.</p> |
| </li> |
| <li> |
| <p><code>check-invalid-html-tags</code> detects invalid HTML (like an unclosed <code><span></code>) |
| in doc comments.</p> |
| </li> |
| <li> |
| <p><code>collect-intra-doc-links</code> resolves <a href="https://doc.rust-lang.org/rustdoc/linking-to-items-by-name.html">intra-doc links</a>.</p> |
| </li> |
| <li> |
| <p><code>collect-trait-impls</code> collects trait impls for each item in the crate. For |
| example, if we define a struct that implements a trait, this pass will note |
| that the struct implements that trait.</p> |
| </li> |
| <li> |
| <p><code>propagate-doc-cfg</code> propagates <code>#[doc(cfg(...))]</code> to child items.</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 rustdoc 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.</p> |
| </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.</p> |
| </li> |
| <li> |
| <p><code>unindent-comments</code> removes excess indentation on comments in order for the |
| Markdown to be parsed correctly. This is necessary because the convention for |
| writing documentation is to provide a space between the <code>///</code> or <code>//!</code> marker |
| and the doc text, but Markdown is whitespace-sensitive. For example, a block |
| of text with four-space indentation is parsed as a code block, so if we didn't |
| unindent comments, these list items</p> |
| <pre><code class="language-rust ignore">/// A list: |
| /// |
| /// - Foo |
| /// - Bar |
| </code></pre> |
| <p>would be parsed as if they were in a code block, which is likely not what the |
| user intended.</p> |
| </li> |
| </ul> |
| <p>There is also a <code>stripper</code> module in <code>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-crate"><a class="header" href="#from-clean-to-crate">From clean to crate</a></h2> |
| <p>This is where the "second phase" in rustdoc begins. This phase primarily lives |
| in the <code>html/</code> folder, and it all starts with <code>run()</code> in <code>html/render.rs</code>. This |
| code is responsible for setting up the <code>Context</code>, <code>SharedContext</code>, and <code>Cache</code> |
| which are used during rendering, copying out the static files which live in |
| every rendered set of documentation (things like the fonts, CSS, and JavaScript |
| that live in <code>html/static/</code>), creating the search index, and printing out the |
| source code rendering, before beginning the process of rendering all the |
| documentation for the crate.</p> |
| <p>Several functions implemented directly on <code>Context</code> take the <code>clean::Crate</code> and |
| set up some state between rendering items or recursing on a module's child |
| items. From here the "page rendering" begins, via an enormous <code>write!()</code> call |
| in <code>html/layout.rs</code>. The parts that actually generate HTML from the items and |
| documentation occurs within a series of <code>std::fmt::Display</code> implementations and |
| functions that pass around a <code>&mut std::fmt::Formatter</code>. The top-level |
| implementation that writes out the page body is the <code>impl<'a> fmt::Display for Item<'a></code> in <code>html/render.rs</code>, which switches out to one of several <code>item_*</code> |
| functions based on the 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 <code>html/render.rs</code> for major items like "what sections should I |
| print for a struct page" or <code>html/format.rs</code> for smaller component pieces like |
| "how should I print a where clause as part of some other item".</p> |
| <p>Whenever rustdoc comes across an item that should print hand-written |
| documentation alongside, it calls out to <code>html/markdown.rs</code> 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 HTML 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 in here |
| (<code>find_testable_code</code>) that specifically scans for Rust code blocks so the |
| test-runner code can find all the doctests in the crate.</p> |
| <h3 id="from-soup-to-nuts"><a class="header" href="#from-soup-to-nuts">From soup to nuts</a></h3> |
| <p>(alternate title: <a href="https://www.youtube.com/watch?v=hOLAGYmUQV0">"An unbroken thread that stretches from those first <code>Cell</code>s |
| to us"</a>)</p> |
| <p>It's important to note that the AST cleaning can ask the compiler for |
| information (crucially, <code>DocContext</code> contains a <code>TyCtxt</code>), but page rendering |
| cannot. The <code>clean::Crate</code> created within <code>run_core</code> is passed outside the |
| compiler context before being handed to <code>html::render::run</code>. This means that a |
| lot of the "supplementary data" that isn't immediately available inside an |
| item's definition, like which trait is the <code>Deref</code> trait used by the language, |
| needs to be collected during cleaning, stored in the <code>DocContext</code>, and passed |
| along to the <code>SharedContext</code> during HTML rendering. This manifests as a bunch |
| of shared state, context variables, and <code>RefCell</code>s.</p> |
| <p>Also of note is that some items that come from "asking the compiler" don't go |
| directly into the <code>DocContext</code> - for example, when loading items from a foreign |
| crate, rustdoc will ask about trait implementations and generate new <code>Item</code>s |
| for the impls based on that information. This goes directly into the returned |
| <code>Crate</code> rather than roundabout through the <code>DocContext</code>. This way, these |
| implementations can be collected alongside the others, right before rendering |
| the HTML.</p> |
| <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 HTML documentation from a Rust |
| crate, but there are couple other major modes that rustdoc runs in. It can also |
| be run on a standalone Markdown file, or it can run doctests 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 HTML.</p> |
| <p>For the latter, rustdoc 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 |
| doctests 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="dotting-is-and-crossing-ts"><a class="header" href="#dotting-is-and-crossing-ts">Dotting i's and crossing t's</a></h2> |
| <p>So that's rustdoc's code in a nutshell, but there's more things in the repo |
| that deal with it. Since we have the full <code>compiletest</code> suite at hand, there's |
| a set of tests in <code>src/test/rustdoc</code> that make sure the final HTML is what we |
| expect in various situations. These tests also use a supplementary script, |
| <code>src/etc/htmldocck.py</code>, that allows it to look through the final HTML using |
| XPath notation to get a precise look at the output. The full description of all |
| the commands available to rustdoc tests (e.g. <a href="https://github.com/rust-lang/rust/blob/master/src/etc/htmldocck.py#L39"><code>@has</code></a> and <a href="https://github.com/rust-lang/rust/blob/master/src/etc/htmldocck.py#L44"><code>@matches</code></a>) is in |
| <a href="https://github.com/rust-lang/rust/blob/master/src/etc/htmldocck.py"><code>htmldocck.py</code></a>.</p> |
| <p>To use multiple crates in a rustdoc test, add <code>// aux-build:filename.rs</code> |
| to the top of the test file. <code>filename.rs</code> should be placed in an <code>auxiliary</code> |
| directory relative to the test file with the comment. If you need to build |
| docs for the auxiliary file, use <code>// build-aux-docs</code>.</p> |
| <p>In addition, there are separate tests for the search index and rustdoc's |
| ability to query it. The files in <code>src/test/rustdoc-js</code> each contain a |
| different search query and the expected results, broken out by search tab. |
| These files are processed by a script in <code>src/tools/rustdoc-js</code> and the Node.js |
| runtime. These tests don't have as thorough of a writeup, but a broad example |
| that features results in all tabs can be found in <code>basic.js</code>. The basic idea is |
| that you match a given <code>QUERY</code> with a set of <code>EXPECTED</code> results, complete with |
| the full item path of each item.</p> |
| <h2 id="testing-locally"><a class="header" href="#testing-locally">Testing locally</a></h2> |
| <p>Some features of the generated HTML documentation might require local |
| storage to be used across pages, which doesn't work well without an HTTP |
| server. To test these features locally, you can run a local HTTP server, like |
| this:</p> |
| <pre><code class="language-bash">$ ./x.py doc library/std |
| # 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 `/std/".</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> |
| |
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