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 /* Because of #77828 we cannot do the simpler:
88 let macro_parent_module = tcx.def_path(tcx.parent_module(def.hir_id).to_def_id());
89 // and instead have to do: */
90 let macro_parent_module = tcx.def_path({
91 use rustc_middle::ty::DefIdTree;
92 tcx.parent(tcx.hir().local_def_id(def.hir_id).to_def_id()).unwrap()
94 // HACK: rustdoc has no way to lookup `doctree::Module`s by their HirId. Instead,
95 // lookup the module by its name, by looking at each path segment one at a time.
96 let mut cur_mod = &mut top_level_module;
97 for path_segment in macro_parent_module.data {
98 let path_segment_ty_ns = match path_segment.data {
99 rustc_hir::definitions::DefPathData::TypeNs(symbol) => symbol,
101 // If the path segment is not from the type namespace
102 // (_e.g._, it can be from a value namespace in the case of `f::` in:
103 // `fn f() { pub macro m() {} }`
104 // then the item is not accessible, and should thus act as if it didn't
105 // exist (unless "associated macros" (inside an `impl`) were a thing…).
106 continue 'exported_macros;
112 .find(|module| module.name == Some(path_segment_ty_ns))
115 cur_mod.macros.push((def, None));
118 self.cx.renderinfo.get_mut().exact_paths = self.exact_paths;
123 fn visit_mod_contents(
126 vis: &'tcx hir::Visibility<'_>,
128 m: &'tcx hir::Mod<'tcx>,
129 name: Option<Symbol>,
131 let mut om = Module::new(name);
132 om.where_outer = span;
133 om.where_inner = m.inner;
135 // Keep track of if there were any private modules in the path.
136 let orig_inside_public_path = self.inside_public_path;
137 self.inside_public_path &= vis.node.is_pub();
138 for i in m.item_ids {
139 let item = self.cx.tcx.hir().expect_item(i.id);
140 self.visit_item(item, None, &mut om);
142 self.inside_public_path = orig_inside_public_path;
146 /// Tries to resolve the target of a `crate use` statement and inlines the
147 /// target if it is defined locally and would not be documented otherwise,
148 /// or when it is specifically requested with `please_inline`.
149 /// (the latter is the case when the import is marked `doc(inline)`)
151 /// Cross-crate inlining occurs later on during crate cleaning
152 /// and follows different rules.
154 /// Returns `true` if the target has been inlined.
155 fn maybe_inline_local(
159 renamed: Option<Symbol>,
161 om: &mut Module<'tcx>,
164 fn inherits_doc_hidden(cx: &core::DocContext<'_>, mut node: hir::HirId) -> bool {
165 while let Some(id) = cx.tcx.hir().get_enclosing_scope(node) {
167 if cx.tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
170 if node == hir::CRATE_HIR_ID {
177 debug!("maybe_inline_local res: {:?}", res);
179 let tcx = self.cx.tcx;
180 let res_did = if let Some(did) = res.opt_def_id() {
186 let use_attrs = tcx.hir().attrs(id);
187 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
188 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
189 || use_attrs.lists(sym::doc).has_word(sym::hidden);
191 // For cross-crate impl inlining we need to know whether items are
192 // reachable in documentation -- a previously nonreachable item can be
193 // made reachable by cross-crate inlining which we're checking here.
194 // (this is done here because we need to know this upfront).
195 if !res_did.is_local() && !is_no_inline {
196 let attrs = clean::inline::load_attrs(self.cx, res_did);
197 let self_is_hidden = attrs.lists(sym::doc).has_word(sym::hidden);
199 if let Res::Def(kind, did) = res {
200 if kind == DefKind::Mod {
201 crate::visit_lib::LibEmbargoVisitor::new(self.cx).visit_mod(did)
203 // All items need to be handled here in case someone wishes to link
204 // to them with intra-doc links
210 .insert(did, AccessLevel::Public);
217 let res_hir_id = match res_did.as_local() {
218 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
219 None => return false,
222 let is_private = !self.cx.renderinfo.borrow().access_levels.is_public(res_did);
223 let is_hidden = inherits_doc_hidden(self.cx, res_hir_id);
225 // Only inline if requested or if the item would otherwise be stripped.
226 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
230 if !self.view_item_stack.insert(res_hir_id) {
234 let ret = match tcx.hir().get(res_hir_id) {
235 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
236 let prev = mem::replace(&mut self.inlining, true);
237 for i in m.item_ids {
238 let i = self.cx.tcx.hir().expect_item(i.id);
239 self.visit_item(i, None, om);
241 self.inlining = prev;
244 Node::Item(it) if !glob => {
245 let prev = mem::replace(&mut self.inlining, true);
246 self.visit_item(it, renamed, om);
247 self.inlining = prev;
250 Node::ForeignItem(it) if !glob => {
251 let prev = mem::replace(&mut self.inlining, true);
252 self.visit_foreign_item(it, renamed, om);
253 self.inlining = prev;
256 Node::MacroDef(def) if !glob => {
257 om.macros.push((def, renamed));
262 self.view_item_stack.remove(&res_hir_id);
268 item: &'tcx hir::Item<'_>,
269 renamed: Option<Symbol>,
270 om: &mut Module<'tcx>,
272 debug!("visiting item {:?}", item);
273 let name = renamed.unwrap_or(item.ident.name);
275 if item.vis.node.is_pub() {
276 let def_id = self.cx.tcx.hir().local_def_id(item.hir_id);
277 self.store_path(def_id.to_def_id());
281 hir::ItemKind::ForeignMod { items, .. } => {
283 let item = self.cx.tcx.hir().foreign_item(item.id);
284 self.visit_foreign_item(item, None, om);
287 // If we're inlining, skip private items.
288 _ if self.inlining && !item.vis.node.is_pub() => {}
289 hir::ItemKind::GlobalAsm(..) => {}
290 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
291 hir::ItemKind::Use(ref path, kind) => {
292 let is_glob = kind == hir::UseKind::Glob;
294 // Struct and variant constructors and proc macro stubs always show up alongside
295 // their definitions, we've already processed them so just discard these.
296 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
300 // If there was a private module in the current path then don't bother inlining
301 // anything as it will probably be stripped anyway.
302 if item.vis.node.is_pub() && self.inside_public_path {
303 let please_inline = item.attrs.iter().any(|item| match item.meta_item_list() {
304 Some(ref list) if item.has_name(sym::doc) => {
305 list.iter().any(|i| i.has_name(sym::inline))
309 let ident = if is_glob { None } else { Some(name) };
310 if self.maybe_inline_local(
322 om.imports.push(Import {
332 hir::ItemKind::Mod(ref m) => {
333 om.mods.push(self.visit_mod_contents(
341 hir::ItemKind::Fn(..)
342 | hir::ItemKind::ExternCrate(..)
343 | hir::ItemKind::Enum(..)
344 | hir::ItemKind::Struct(..)
345 | hir::ItemKind::Union(..)
346 | hir::ItemKind::TyAlias(..)
347 | hir::ItemKind::OpaqueTy(..)
348 | hir::ItemKind::Static(..)
349 | hir::ItemKind::Trait(..)
350 | hir::ItemKind::TraitAlias(..) => om.items.push((item, renamed)),
351 hir::ItemKind::Const(..) => {
352 // Underscore constants do not correspond to a nameable item and
353 // so are never useful in documentation.
354 if name != kw::Underscore {
355 om.items.push((item, renamed));
358 hir::ItemKind::Impl { ref of_trait, .. } => {
359 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
360 // them up regardless of where they're located.
361 if !self.inlining && of_trait.is_none() {
362 om.items.push((item, None));
368 fn visit_foreign_item(
370 item: &'tcx hir::ForeignItem<'_>,
371 renamed: Option<Symbol>,
372 om: &mut Module<'tcx>,
374 // If inlining we only want to include public functions.
375 if !self.inlining || item.vis.node.is_pub() {
376 om.foreigns.push((item, renamed));