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;
11 use rustc_span::source_map::Spanned;
12 use rustc_span::symbol::{kw, sym, Symbol};
13 use rustc_span::{self, Span};
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 // Also, is there some reason that this doesn't use the 'visit'
33 // framework from syntax?.
35 crate struct RustdocVisitor<'a, 'tcx> {
36 cx: &'a mut core::DocContext<'tcx>,
37 view_item_stack: FxHashSet<hir::HirId>,
39 /// Are the current module and all of its parents public?
40 inside_public_path: bool,
41 exact_paths: FxHashMap<DefId, Vec<String>>,
44 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
45 crate fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
46 // If the root is re-exported, terminate all recursion.
47 let mut stack = FxHashSet::default();
48 stack.insert(hir::CRATE_HIR_ID);
51 view_item_stack: stack,
53 inside_public_path: true,
54 exact_paths: FxHashMap::default(),
58 fn store_path(&mut self, did: DefId) {
59 let tcx = self.cx.tcx;
60 self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
63 crate fn visit(mut self, krate: &'tcx hir::Crate<'_>) -> Module<'tcx> {
64 let mut top_level_module = self.visit_mod_contents(
66 &Spanned { span: rustc_span::DUMMY_SP, node: hir::VisibilityKind::Public },
71 top_level_module.is_crate = true;
72 // Attach the crate's exported macros to the top-level module.
73 // In the case of macros 2.0 (`pub macro`), and for built-in `derive`s or attributes as
74 // well (_e.g._, `Copy`), these are wrongly bundled in there too, so we need to fix that by
75 // moving them back to their correct locations.
76 'exported_macros: for def in krate.exported_macros {
77 // The `def` of a macro in `exported_macros` should correspond to either:
78 // - a `#[macro_export] macro_rules!` macro,
79 // - a built-in `derive` (or attribute) macro such as the ones in `::core`,
81 // Only the last two need to be fixed, thus:
82 if def.ast.macro_rules {
83 top_level_module.macros.push((def, None));
84 continue 'exported_macros;
86 let tcx = self.cx.tcx;
87 // Note: this is not the same as `.parent_module()`. Indeed, the latter looks
88 // for the closest module _ancestor_, which is not necessarily a direct parent
89 // (since a direct parent isn't necessarily a module, c.f. #77828).
90 let macro_parent_def_id = {
91 use rustc_middle::ty::DefIdTree;
92 tcx.parent(def.def_id.to_def_id()).unwrap()
94 let macro_parent_path = tcx.def_path(macro_parent_def_id);
95 // HACK: rustdoc has no way to lookup `doctree::Module`s by their HirId. Instead,
96 // lookup the module by its name, by looking at each path segment one at a time.
97 let mut cur_mod = &mut top_level_module;
98 for path_segment in macro_parent_path.data {
99 // Path segments may refer to a module (in which case they belong to the type
100 // namespace), which is _necessary_ for the macro to be accessible outside it
101 // (no "associated macros" as of yet). Else we bail with an outer `continue`.
102 let path_segment_ty_ns = match path_segment.data {
103 rustc_hir::definitions::DefPathData::TypeNs(symbol) => symbol,
104 _ => continue 'exported_macros,
106 // Descend into the child module that matches this path segment (if any).
107 match cur_mod.mods.iter_mut().find(|child| child.name == Some(path_segment_ty_ns)) {
108 Some(child_mod) => cur_mod = &mut *child_mod,
109 None => continue 'exported_macros,
112 let cur_mod_def_id = tcx.hir().local_def_id(cur_mod.id).to_def_id();
113 assert_eq!(cur_mod_def_id, macro_parent_def_id);
114 cur_mod.macros.push((def, None));
116 self.cx.renderinfo.exact_paths = self.exact_paths;
120 fn visit_mod_contents(
123 vis: &'tcx hir::Visibility<'_>,
125 m: &'tcx hir::Mod<'tcx>,
126 name: Option<Symbol>,
128 let mut om = Module::new(name);
129 om.where_outer = span;
130 om.where_inner = m.inner;
132 // Keep track of if there were any private modules in the path.
133 let orig_inside_public_path = self.inside_public_path;
134 self.inside_public_path &= vis.node.is_pub();
135 for &i in m.item_ids {
136 let item = self.cx.tcx.hir().item(i);
137 self.visit_item(item, None, &mut om);
139 self.inside_public_path = orig_inside_public_path;
143 /// Tries to resolve the target of a `crate use` statement and inlines the
144 /// target if it is defined locally and would not be documented otherwise,
145 /// or when it is specifically requested with `please_inline`.
146 /// (the latter is the case when the import is marked `doc(inline)`)
148 /// Cross-crate inlining occurs later on during crate cleaning
149 /// and follows different rules.
151 /// Returns `true` if the target has been inlined.
152 fn maybe_inline_local(
156 renamed: Option<Symbol>,
158 om: &mut Module<'tcx>,
161 fn inherits_doc_hidden(cx: &core::DocContext<'_>, mut node: hir::HirId) -> bool {
162 while let Some(id) = cx.tcx.hir().get_enclosing_scope(node) {
164 if cx.tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
167 if node == hir::CRATE_HIR_ID {
174 debug!("maybe_inline_local res: {:?}", res);
176 let tcx = self.cx.tcx;
177 let res_did = if let Some(did) = res.opt_def_id() {
183 let use_attrs = tcx.hir().attrs(id);
184 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
185 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
186 || use_attrs.lists(sym::doc).has_word(sym::hidden);
188 // For cross-crate impl inlining we need to know whether items are
189 // reachable in documentation -- a previously nonreachable item can be
190 // made reachable by cross-crate inlining which we're checking here.
191 // (this is done here because we need to know this upfront).
192 if !res_did.is_local() && !is_no_inline {
193 let attrs = clean::inline::load_attrs(self.cx, res_did);
194 let self_is_hidden = attrs.lists(sym::doc).has_word(sym::hidden);
196 if let Res::Def(kind, did) = res {
197 if kind == DefKind::Mod {
198 crate::visit_lib::LibEmbargoVisitor::new(self.cx).visit_mod(did)
200 // All items need to be handled here in case someone wishes to link
201 // to them with intra-doc links
202 self.cx.renderinfo.access_levels.map.insert(did, AccessLevel::Public);
209 let res_hir_id = match res_did.as_local() {
210 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
211 None => return false,
214 let is_private = !self.cx.renderinfo.access_levels.is_public(res_did);
215 let is_hidden = inherits_doc_hidden(self.cx, res_hir_id);
217 // Only inline if requested or if the item would otherwise be stripped.
218 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
222 if !self.view_item_stack.insert(res_hir_id) {
226 let ret = match tcx.hir().get(res_hir_id) {
227 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
228 let prev = mem::replace(&mut self.inlining, true);
229 for &i in m.item_ids {
230 let i = self.cx.tcx.hir().item(i);
231 self.visit_item(i, None, om);
233 self.inlining = prev;
236 Node::Item(it) if !glob => {
237 let prev = mem::replace(&mut self.inlining, true);
238 self.visit_item(it, renamed, om);
239 self.inlining = prev;
242 Node::ForeignItem(it) if !glob => {
243 let prev = mem::replace(&mut self.inlining, true);
244 self.visit_foreign_item(it, renamed, om);
245 self.inlining = prev;
248 Node::MacroDef(def) if !glob => {
249 om.macros.push((def, renamed));
254 self.view_item_stack.remove(&res_hir_id);
260 item: &'tcx hir::Item<'_>,
261 renamed: Option<Symbol>,
262 om: &mut Module<'tcx>,
264 debug!("visiting item {:?}", item);
265 let name = renamed.unwrap_or(item.ident.name);
267 if item.vis.node.is_pub() {
268 self.store_path(item.def_id.to_def_id());
272 hir::ItemKind::ForeignMod { items, .. } => {
274 let item = self.cx.tcx.hir().foreign_item(item.id);
275 self.visit_foreign_item(item, None, om);
278 // If we're inlining, skip private items.
279 _ if self.inlining && !item.vis.node.is_pub() => {}
280 hir::ItemKind::GlobalAsm(..) => {}
281 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
282 hir::ItemKind::Use(ref path, kind) => {
283 let is_glob = kind == hir::UseKind::Glob;
285 // Struct and variant constructors and proc macro stubs always show up alongside
286 // their definitions, we've already processed them so just discard these.
287 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
291 // If there was a private module in the current path then don't bother inlining
292 // anything as it will probably be stripped anyway.
293 if item.vis.node.is_pub() && self.inside_public_path {
294 let please_inline = item.attrs.iter().any(|item| match item.meta_item_list() {
295 Some(ref list) if item.has_name(sym::doc) => {
296 list.iter().any(|i| i.has_name(sym::inline))
300 let ident = if is_glob { None } else { Some(name) };
301 if self.maybe_inline_local(
313 om.items.push((item, renamed))
315 hir::ItemKind::Mod(ref m) => {
316 om.mods.push(self.visit_mod_contents(
324 hir::ItemKind::Fn(..)
325 | hir::ItemKind::ExternCrate(..)
326 | hir::ItemKind::Enum(..)
327 | hir::ItemKind::Struct(..)
328 | hir::ItemKind::Union(..)
329 | hir::ItemKind::TyAlias(..)
330 | hir::ItemKind::OpaqueTy(..)
331 | hir::ItemKind::Static(..)
332 | hir::ItemKind::Trait(..)
333 | hir::ItemKind::TraitAlias(..) => om.items.push((item, renamed)),
334 hir::ItemKind::Const(..) => {
335 // Underscore constants do not correspond to a nameable item and
336 // so are never useful in documentation.
337 if name != kw::Underscore {
338 om.items.push((item, renamed));
341 hir::ItemKind::Impl(ref impl_) => {
342 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
343 // them up regardless of where they're located.
344 if !self.inlining && impl_.of_trait.is_none() {
345 om.items.push((item, None));
351 fn visit_foreign_item(
353 item: &'tcx hir::ForeignItem<'_>,
354 renamed: Option<Symbol>,
355 om: &mut Module<'tcx>,
357 // If inlining we only want to include public functions.
358 if !self.inlining || item.vis.node.is_pub() {
359 om.foreigns.push((item, renamed));