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_middle::middle::privacy::AccessLevel;
10 use rustc_middle::ty::TyCtxt;
12 use rustc_span::source_map::Spanned;
13 use rustc_span::symbol::{kw, sym, Symbol};
17 use crate::clean::{self, AttributesExt, NestedAttributesExt};
19 use crate::doctree::*;
21 // FIXME: Should this be replaced with tcx.def_path_str?
22 fn def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<String> {
23 let crate_name = tcx.crate_name(did.krate).to_string();
24 let relative = tcx.def_path(did).data.into_iter().filter_map(|elem| {
25 // extern blocks have an empty name
26 let s = elem.data.to_string();
27 if !s.is_empty() { Some(s) } else { None }
29 std::iter::once(crate_name).chain(relative).collect()
32 crate fn inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool {
33 while let Some(id) = tcx.hir().get_enclosing_scope(node) {
35 if tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
42 // Also, is there some reason that this doesn't use the 'visit'
43 // framework from syntax?.
45 crate struct RustdocVisitor<'a, 'tcx> {
46 cx: &'a mut core::DocContext<'tcx>,
47 view_item_stack: FxHashSet<hir::HirId>,
49 /// Are the current module and all of its parents public?
50 inside_public_path: bool,
51 exact_paths: FxHashMap<DefId, Vec<String>>,
54 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
55 crate fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
56 // If the root is re-exported, terminate all recursion.
57 let mut stack = FxHashSet::default();
58 stack.insert(hir::CRATE_HIR_ID);
61 view_item_stack: stack,
63 inside_public_path: true,
64 exact_paths: FxHashMap::default(),
68 fn store_path(&mut self, did: DefId) {
69 let tcx = self.cx.tcx;
70 self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
73 crate fn visit(mut self, krate: &'tcx hir::Crate<'_>) -> Module<'tcx> {
74 let span = krate.item.inner;
75 let mut top_level_module = self.visit_mod_contents(
76 &Spanned { span, node: hir::VisibilityKind::Public },
79 self.cx.tcx.crate_name,
81 // Attach the crate's exported macros to the top-level module.
82 // In the case of macros 2.0 (`pub macro`), and for built-in `derive`s or attributes as
83 // well (_e.g._, `Copy`), these are wrongly bundled in there too, so we need to fix that by
84 // moving them back to their correct locations.
85 'exported_macros: for def in krate.exported_macros {
86 // The `def` of a macro in `exported_macros` should correspond to either:
87 // - a `#[macro_export] macro_rules!` macro,
88 // - a built-in `derive` (or attribute) macro such as the ones in `::core`,
90 // Only the last two need to be fixed, thus:
91 if def.ast.macro_rules {
92 top_level_module.macros.push((def, None));
93 continue 'exported_macros;
95 let tcx = self.cx.tcx;
96 // Note: this is not the same as `.parent_module()`. Indeed, the latter looks
97 // for the closest module _ancestor_, which is not necessarily a direct parent
98 // (since a direct parent isn't necessarily a module, c.f. #77828).
99 let macro_parent_def_id = {
100 use rustc_middle::ty::DefIdTree;
101 tcx.parent(def.def_id.to_def_id()).unwrap()
103 let macro_parent_path = tcx.def_path(macro_parent_def_id);
104 // HACK: rustdoc has no way to lookup `doctree::Module`s by their HirId. Instead,
105 // lookup the module by its name, by looking at each path segment one at a time.
106 let mut cur_mod = &mut top_level_module;
107 for path_segment in macro_parent_path.data {
108 // Path segments may refer to a module (in which case they belong to the type
109 // namespace), which is _necessary_ for the macro to be accessible outside it
110 // (no "associated macros" as of yet). Else we bail with an outer `continue`.
111 let path_segment_ty_ns = match path_segment.data {
112 rustc_hir::definitions::DefPathData::TypeNs(symbol) => symbol,
113 _ => continue 'exported_macros,
115 // Descend into the child module that matches this path segment (if any).
116 match cur_mod.mods.iter_mut().find(|child| child.name == path_segment_ty_ns) {
117 Some(child_mod) => cur_mod = &mut *child_mod,
118 None => continue 'exported_macros,
121 let cur_mod_def_id = tcx.hir().local_def_id(cur_mod.id).to_def_id();
122 assert_eq!(cur_mod_def_id, macro_parent_def_id);
123 cur_mod.macros.push((def, None));
125 self.cx.cache.exact_paths = self.exact_paths;
129 fn visit_mod_contents(
131 vis: &hir::Visibility<'_>,
133 m: &'tcx hir::Mod<'tcx>,
136 let mut om = Module::new(name, id, m.inner);
137 // Keep track of if there were any private modules in the path.
138 let orig_inside_public_path = self.inside_public_path;
139 self.inside_public_path &= vis.node.is_pub();
140 for &i in m.item_ids {
141 let item = self.cx.tcx.hir().item(i);
142 self.visit_item(item, None, &mut om);
144 self.inside_public_path = orig_inside_public_path;
148 /// Tries to resolve the target of a `pub use` statement and inlines the
149 /// target if it is defined locally and would not be documented otherwise,
150 /// or when it is specifically requested with `please_inline`.
151 /// (the latter is the case when the import is marked `doc(inline)`)
153 /// Cross-crate inlining occurs later on during crate cleaning
154 /// and follows different rules.
156 /// Returns `true` if the target has been inlined.
157 fn maybe_inline_local(
161 renamed: Option<Symbol>,
163 om: &mut Module<'tcx>,
166 debug!("maybe_inline_local res: {:?}", res);
168 let tcx = self.cx.tcx;
169 let res_did = if let Some(did) = res.opt_def_id() {
175 let use_attrs = tcx.hir().attrs(id);
176 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
177 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
178 || use_attrs.lists(sym::doc).has_word(sym::hidden);
180 // For cross-crate impl inlining we need to know whether items are
181 // reachable in documentation -- a previously unreachable item can be
182 // made reachable by cross-crate inlining which we're checking here.
183 // (this is done here because we need to know this upfront).
184 if !res_did.is_local() && !is_no_inline {
185 let attrs = clean::inline::load_attrs(self.cx, res_did);
186 let self_is_hidden = attrs.lists(sym::doc).has_word(sym::hidden);
188 if let Res::Def(kind, did) = res {
189 if kind == DefKind::Mod {
190 crate::visit_lib::LibEmbargoVisitor::new(self.cx).visit_mod(did)
192 // All items need to be handled here in case someone wishes to link
193 // to them with intra-doc links
194 self.cx.cache.access_levels.map.insert(did.into(), AccessLevel::Public);
201 let res_hir_id = match res_did.as_local() {
202 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
203 None => return false,
206 let is_private = !self.cx.cache.access_levels.is_public(res_did.into());
207 let is_hidden = inherits_doc_hidden(self.cx.tcx, res_hir_id);
209 // Only inline if requested or if the item would otherwise be stripped.
210 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
214 if !self.view_item_stack.insert(res_hir_id) {
218 let ret = match tcx.hir().get(res_hir_id) {
219 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
220 let prev = mem::replace(&mut self.inlining, true);
221 for &i in m.item_ids {
222 let i = self.cx.tcx.hir().item(i);
223 self.visit_item(i, None, om);
225 self.inlining = prev;
228 Node::Item(it) if !glob => {
229 let prev = mem::replace(&mut self.inlining, true);
230 self.visit_item(it, renamed, om);
231 self.inlining = prev;
234 Node::ForeignItem(it) if !glob => {
235 let prev = mem::replace(&mut self.inlining, true);
236 self.visit_foreign_item(it, renamed, om);
237 self.inlining = prev;
240 Node::MacroDef(def) if !glob => {
241 om.macros.push((def, renamed));
246 self.view_item_stack.remove(&res_hir_id);
252 item: &'tcx hir::Item<'_>,
253 renamed: Option<Symbol>,
254 om: &mut Module<'tcx>,
256 debug!("visiting item {:?}", item);
257 let name = renamed.unwrap_or(item.ident.name);
259 if item.vis.node.is_pub() {
260 self.store_path(item.def_id.to_def_id());
264 hir::ItemKind::ForeignMod { items, .. } => {
266 let item = self.cx.tcx.hir().foreign_item(item.id);
267 self.visit_foreign_item(item, None, om);
270 // If we're inlining, skip private items.
271 _ if self.inlining && !item.vis.node.is_pub() => {}
272 hir::ItemKind::GlobalAsm(..) => {}
273 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
274 hir::ItemKind::Use(ref path, kind) => {
275 let is_glob = kind == hir::UseKind::Glob;
277 // Struct and variant constructors and proc macro stubs always show up alongside
278 // their definitions, we've already processed them so just discard these.
279 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
283 let attrs = self.cx.tcx.hir().attrs(item.hir_id());
285 // If there was a private module in the current path then don't bother inlining
286 // anything as it will probably be stripped anyway.
287 if item.vis.node.is_pub() && self.inside_public_path {
288 let please_inline = attrs.iter().any(|item| match item.meta_item_list() {
289 Some(ref list) if item.has_name(sym::doc) => {
290 list.iter().any(|i| i.has_name(sym::inline))
294 let ident = if is_glob { None } else { Some(name) };
295 if self.maybe_inline_local(
307 om.items.push((item, renamed))
309 hir::ItemKind::Mod(ref m) => {
310 om.mods.push(self.visit_mod_contents(&item.vis, item.hir_id(), m, name));
312 hir::ItemKind::Fn(..)
313 | hir::ItemKind::ExternCrate(..)
314 | hir::ItemKind::Enum(..)
315 | hir::ItemKind::Struct(..)
316 | hir::ItemKind::Union(..)
317 | hir::ItemKind::TyAlias(..)
318 | hir::ItemKind::OpaqueTy(..)
319 | hir::ItemKind::Static(..)
320 | hir::ItemKind::Trait(..)
321 | hir::ItemKind::TraitAlias(..) => om.items.push((item, renamed)),
322 hir::ItemKind::Const(..) => {
323 // Underscore constants do not correspond to a nameable item and
324 // so are never useful in documentation.
325 if name != kw::Underscore {
326 om.items.push((item, renamed));
329 hir::ItemKind::Impl(ref impl_) => {
330 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
331 // them up regardless of where they're located.
332 if !self.inlining && impl_.of_trait.is_none() {
333 om.items.push((item, None));
339 fn visit_foreign_item(
341 item: &'tcx hir::ForeignItem<'_>,
342 renamed: Option<Symbol>,
343 om: &mut Module<'tcx>,
345 // If inlining we only want to include public functions.
346 if !self.inlining || item.vis.node.is_pub() {
347 om.foreigns.push((item, renamed));