1 //! The Rust AST Visitor. Extracts useful information and massages it into a form
2 //! usable for `clean`.
4 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
6 use rustc_hir::def::{DefKind, Res};
7 use rustc_hir::def_id::DefId;
9 use rustc_hir::CRATE_HIR_ID;
10 use rustc_middle::middle::privacy::AccessLevel;
11 use rustc_middle::ty::TyCtxt;
12 use rustc_span::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
13 use rustc_span::source_map::Spanned;
14 use rustc_span::symbol::{kw, sym, Symbol};
18 use crate::clean::{self, cfg::Cfg, AttributesExt, NestedAttributesExt};
20 use crate::doctree::*;
22 // FIXME: Should this be replaced with tcx.def_path_str?
23 fn def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<String> {
24 let crate_name = tcx.crate_name(did.krate).to_string();
25 let relative = tcx.def_path(did).data.into_iter().filter_map(|elem| {
26 // extern blocks have an empty name
27 let s = elem.data.to_string();
28 if !s.is_empty() { Some(s) } else { None }
30 std::iter::once(crate_name).chain(relative).collect()
33 crate fn inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool {
34 while let Some(id) = tcx.hir().get_enclosing_scope(node) {
36 if tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
43 // Also, is there some reason that this doesn't use the 'visit'
44 // framework from syntax?.
46 crate struct RustdocVisitor<'a, 'tcx> {
47 cx: &'a mut core::DocContext<'tcx>,
48 view_item_stack: FxHashSet<hir::HirId>,
50 /// Are the current module and all of its parents public?
51 inside_public_path: bool,
52 exact_paths: FxHashMap<DefId, Vec<String>>,
55 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
56 crate fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
57 // If the root is re-exported, terminate all recursion.
58 let mut stack = FxHashSet::default();
59 stack.insert(hir::CRATE_HIR_ID);
62 view_item_stack: stack,
64 inside_public_path: true,
65 exact_paths: FxHashMap::default(),
69 fn store_path(&mut self, did: DefId) {
70 let tcx = self.cx.tcx;
71 self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
74 crate fn visit(mut self) -> Module<'tcx> {
75 let span = self.cx.tcx.def_span(CRATE_DEF_ID);
76 let mut top_level_module = self.visit_mod_contents(
77 &Spanned { span, node: hir::VisibilityKind::Public },
79 self.cx.tcx.hir().root_module(),
80 self.cx.tcx.crate_name(LOCAL_CRATE),
83 // `#[macro_export] macro_rules!` items are reexported at the top level of the
84 // crate, regardless of where they're defined. We want to document the
85 // top level rexport of the macro, not its original definition, since
86 // the rexport defines the path that a user will actually see. Accordingly,
87 // we add the rexport as an item here, and then skip over the original
88 // definition in `visit_item()` below.
90 // We also skip `#[macro_export] macro_rules!` that have already been inserted,
91 // it can happen if within the same module a `#[macro_export] macro_rules!`
92 // is declared but also a reexport of itself producing two exports of the same
93 // macro in the same module.
94 let mut inserted = FxHashSet::default();
95 for export in self.cx.tcx.module_exports(CRATE_DEF_ID).unwrap_or(&[]) {
96 if let Res::Def(DefKind::Macro(_), def_id) = export.res {
97 if let Some(local_def_id) = def_id.as_local() {
98 if self.cx.tcx.has_attr(def_id, sym::macro_export) {
99 if inserted.insert(def_id) {
100 let hir_id = self.cx.tcx.hir().local_def_id_to_hir_id(local_def_id);
101 let item = self.cx.tcx.hir().expect_item(hir_id);
102 top_level_module.items.push((item, None));
109 self.cx.cache.hidden_cfg = self
115 .filter(|attr| attr.has_name(sym::doc))
116 .flat_map(|attr| attr.meta_item_list().into_iter().flatten())
117 .filter(|attr| attr.has_name(sym::cfg_hide))
119 attr.meta_item_list()
123 Cfg::parse(attr.meta_item()?)
124 .map_err(|e| self.cx.sess().diagnostic().span_err(e.span, e.msg))
131 self.cx.cache.exact_paths = self.exact_paths;
135 fn visit_mod_contents(
137 vis: &hir::Visibility<'_>,
139 m: &'tcx hir::Mod<'tcx>,
142 let mut om = Module::new(name, id, m.inner);
143 // Keep track of if there were any private modules in the path.
144 let orig_inside_public_path = self.inside_public_path;
145 self.inside_public_path &= vis.node.is_pub();
146 for &i in m.item_ids {
147 let item = self.cx.tcx.hir().item(i);
148 self.visit_item(item, None, &mut om);
150 self.inside_public_path = orig_inside_public_path;
154 /// Tries to resolve the target of a `pub use` statement and inlines the
155 /// target if it is defined locally and would not be documented otherwise,
156 /// or when it is specifically requested with `please_inline`.
157 /// (the latter is the case when the import is marked `doc(inline)`)
159 /// Cross-crate inlining occurs later on during crate cleaning
160 /// and follows different rules.
162 /// Returns `true` if the target has been inlined.
163 fn maybe_inline_local(
167 renamed: Option<Symbol>,
169 om: &mut Module<'tcx>,
172 debug!("maybe_inline_local res: {:?}", res);
174 let tcx = self.cx.tcx;
175 let res_did = if let Some(did) = res.opt_def_id() {
181 let use_attrs = tcx.hir().attrs(id);
182 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
183 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
184 || use_attrs.lists(sym::doc).has_word(sym::hidden);
186 // For cross-crate impl inlining we need to know whether items are
187 // reachable in documentation -- a previously unreachable item can be
188 // made reachable by cross-crate inlining which we're checking here.
189 // (this is done here because we need to know this upfront).
190 if !res_did.is_local() && !is_no_inline {
191 let attrs = clean::inline::load_attrs(self.cx, res_did);
192 let self_is_hidden = attrs.lists(sym::doc).has_word(sym::hidden);
194 if let Res::Def(kind, did) = res {
195 if kind == DefKind::Mod {
196 crate::visit_lib::LibEmbargoVisitor::new(self.cx).visit_mod(did)
198 // All items need to be handled here in case someone wishes to link
199 // to them with intra-doc links
200 self.cx.cache.access_levels.map.insert(did, AccessLevel::Public);
207 let res_hir_id = match res_did.as_local() {
208 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
209 None => return false,
212 let is_private = !self.cx.cache.access_levels.is_public(res_did);
213 let is_hidden = inherits_doc_hidden(self.cx.tcx, res_hir_id);
215 // Only inline if requested or if the item would otherwise be stripped.
216 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
220 if !self.view_item_stack.insert(res_hir_id) {
224 let ret = match tcx.hir().get(res_hir_id) {
225 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
226 let prev = mem::replace(&mut self.inlining, true);
227 for &i in m.item_ids {
228 let i = self.cx.tcx.hir().item(i);
229 self.visit_item(i, None, om);
231 self.inlining = prev;
234 Node::Item(it) if !glob => {
235 let prev = mem::replace(&mut self.inlining, true);
236 self.visit_item(it, renamed, om);
237 self.inlining = prev;
240 Node::ForeignItem(it) if !glob => {
241 let prev = mem::replace(&mut self.inlining, true);
242 self.visit_foreign_item(it, renamed, om);
243 self.inlining = prev;
248 self.view_item_stack.remove(&res_hir_id);
254 item: &'tcx hir::Item<'_>,
255 renamed: Option<Symbol>,
256 om: &mut Module<'tcx>,
258 debug!("visiting item {:?}", item);
259 let name = renamed.unwrap_or(item.ident.name);
261 let def_id = item.def_id.to_def_id();
262 let is_pub = item.vis.node.is_pub() || self.cx.tcx.has_attr(def_id, sym::macro_export);
265 self.store_path(item.def_id.to_def_id());
269 hir::ItemKind::ForeignMod { items, .. } => {
271 let item = self.cx.tcx.hir().foreign_item(item.id);
272 self.visit_foreign_item(item, None, om);
275 // If we're inlining, skip private items.
276 _ if self.inlining && !is_pub => {}
277 hir::ItemKind::GlobalAsm(..) => {}
278 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
279 hir::ItemKind::Use(path, kind) => {
280 let is_glob = kind == hir::UseKind::Glob;
282 // Struct and variant constructors and proc macro stubs always show up alongside
283 // their definitions, we've already processed them so just discard these.
284 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
288 let attrs = self.cx.tcx.hir().attrs(item.hir_id());
290 // If there was a private module in the current path then don't bother inlining
291 // anything as it will probably be stripped anyway.
292 if is_pub && self.inside_public_path {
293 let please_inline = attrs.iter().any(|item| match item.meta_item_list() {
294 Some(ref list) if item.has_name(sym::doc) => {
295 list.iter().any(|i| i.has_name(sym::inline))
299 let ident = if is_glob { None } else { Some(name) };
300 if self.maybe_inline_local(
312 om.items.push((item, renamed))
314 hir::ItemKind::Macro(ref macro_def) => {
315 // `#[macro_export] macro_rules!` items are handled seperately in `visit()`,
316 // above, since they need to be documented at the module top level. Accordingly,
317 // we only want to handle macros if one of three conditions holds:
319 // 1. This macro was defined by `macro`, and thus isn't covered by the case
321 // 2. This macro isn't marked with `#[macro_export]`, and thus isn't covered
322 // by the case above.
323 // 3. We're inlining, since a reexport where inlining has been requested
324 // should be inlined even if it is also documented at the top level.
326 let def_id = item.def_id.to_def_id();
327 let is_macro_2_0 = !macro_def.macro_rules;
328 let nonexported = !self.cx.tcx.has_attr(def_id, sym::macro_export);
330 if is_macro_2_0 || nonexported || self.inlining {
331 om.items.push((item, renamed));
334 hir::ItemKind::Mod(ref m) => {
335 om.mods.push(self.visit_mod_contents(&item.vis, item.hir_id(), m, name));
337 hir::ItemKind::Fn(..)
338 | hir::ItemKind::ExternCrate(..)
339 | hir::ItemKind::Enum(..)
340 | hir::ItemKind::Struct(..)
341 | hir::ItemKind::Union(..)
342 | hir::ItemKind::TyAlias(..)
343 | hir::ItemKind::OpaqueTy(..)
344 | hir::ItemKind::Static(..)
345 | hir::ItemKind::Trait(..)
346 | hir::ItemKind::TraitAlias(..) => om.items.push((item, renamed)),
347 hir::ItemKind::Const(..) => {
348 // Underscore constants do not correspond to a nameable item and
349 // so are never useful in documentation.
350 if name != kw::Underscore {
351 om.items.push((item, renamed));
354 hir::ItemKind::Impl(ref impl_) => {
355 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
356 // them up regardless of where they're located.
357 if !self.inlining && impl_.of_trait.is_none() {
358 om.items.push((item, None));
364 fn visit_foreign_item(
366 item: &'tcx hir::ForeignItem<'_>,
367 renamed: Option<Symbol>,
368 om: &mut Module<'tcx>,
370 // If inlining we only want to include public functions.
371 if !self.inlining || item.vis.node.is_pub() {
372 om.foreigns.push((item, renamed));