1 //! The Rust AST Visitor. Extracts useful information and massages it into a form
2 //! usable for `clean`.
3
4 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
5 use rustc_hir as hir;
6 use rustc_hir::def::{DefKind, Res};
7 use rustc_hir::def_id::DefId;
8 use rustc_hir::Node;
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::symbol::{kw, sym, Symbol};
14 use rustc_span::Span;
15
16 use std::mem;
17
18 use crate::clean::{self, cfg::Cfg, AttributesExt, NestedAttributesExt};
19 use crate::core;
20
21 /// This module is used to store stuff from Rust's AST in a more convenient
22 /// manner (and with prettier names) before cleaning.
23 #[derive(Debug)]
24 crate struct Module<'hir> {
25 crate name: Symbol,
26 crate where_inner: Span,
27 crate mods: Vec<Module<'hir>>,
28 crate id: hir::HirId,
29 // (item, renamed)
30 crate items: Vec<(&'hir hir::Item<'hir>, Option<Symbol>)>,
31 crate foreigns: Vec<(&'hir hir::ForeignItem<'hir>, Option<Symbol>)>,
32 }
33
34 impl Module<'hir> {
new(name: Symbol, id: hir::HirId, where_inner: Span) -> Module<'hir>35 crate fn new(name: Symbol, id: hir::HirId, where_inner: Span) -> Module<'hir> {
36 Module { name, id, where_inner, mods: Vec::new(), items: Vec::new(), foreigns: Vec::new() }
37 }
38
where_outer(&self, tcx: TyCtxt<'_>) -> Span39 crate fn where_outer(&self, tcx: TyCtxt<'_>) -> Span {
40 tcx.hir().span(self.id)
41 }
42 }
43
44 // FIXME: Should this be replaced with tcx.def_path_str?
def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<String>45 fn def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<String> {
46 let crate_name = tcx.crate_name(did.krate).to_string();
47 let relative = tcx.def_path(did).data.into_iter().filter_map(|elem| {
48 // extern blocks have an empty name
49 let s = elem.data.to_string();
50 if !s.is_empty() { Some(s) } else { None }
51 });
52 std::iter::once(crate_name).chain(relative).collect()
53 }
54
inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool55 crate fn inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool {
56 while let Some(id) = tcx.hir().get_enclosing_scope(node) {
57 node = id;
58 if tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
59 return true;
60 }
61 }
62 false
63 }
64
65 // Also, is there some reason that this doesn't use the 'visit'
66 // framework from syntax?.
67
68 crate struct RustdocVisitor<'a, 'tcx> {
69 cx: &'a mut core::DocContext<'tcx>,
70 view_item_stack: FxHashSet<hir::HirId>,
71 inlining: bool,
72 /// Are the current module and all of its parents public?
73 inside_public_path: bool,
74 exact_paths: FxHashMap<DefId, Vec<String>>,
75 }
76
77 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx>78 crate fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
79 // If the root is re-exported, terminate all recursion.
80 let mut stack = FxHashSet::default();
81 stack.insert(hir::CRATE_HIR_ID);
82 RustdocVisitor {
83 cx,
84 view_item_stack: stack,
85 inlining: false,
86 inside_public_path: true,
87 exact_paths: FxHashMap::default(),
88 }
89 }
90
store_path(&mut self, did: DefId)91 fn store_path(&mut self, did: DefId) {
92 let tcx = self.cx.tcx;
93 self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
94 }
95
visit(mut self) -> Module<'tcx>96 crate fn visit(mut self) -> Module<'tcx> {
97 let mut top_level_module = self.visit_mod_contents(
98 hir::CRATE_HIR_ID,
99 self.cx.tcx.hir().root_module(),
100 self.cx.tcx.crate_name(LOCAL_CRATE),
101 );
102
103 // `#[macro_export] macro_rules!` items are reexported at the top level of the
104 // crate, regardless of where they're defined. We want to document the
105 // top level rexport of the macro, not its original definition, since
106 // the rexport defines the path that a user will actually see. Accordingly,
107 // we add the rexport as an item here, and then skip over the original
108 // definition in `visit_item()` below.
109 //
110 // We also skip `#[macro_export] macro_rules!` that have already been inserted,
111 // it can happen if within the same module a `#[macro_export] macro_rules!`
112 // is declared but also a reexport of itself producing two exports of the same
113 // macro in the same module.
114 let mut inserted = FxHashSet::default();
115 for export in self.cx.tcx.module_exports(CRATE_DEF_ID).unwrap_or(&[]) {
116 if let Res::Def(DefKind::Macro(_), def_id) = export.res {
117 if let Some(local_def_id) = def_id.as_local() {
118 if self.cx.tcx.has_attr(def_id, sym::macro_export) {
119 if inserted.insert(def_id) {
120 let hir_id = self.cx.tcx.hir().local_def_id_to_hir_id(local_def_id);
121 let item = self.cx.tcx.hir().expect_item(hir_id);
122 top_level_module.items.push((item, None));
123 }
124 }
125 }
126 }
127 }
128
129 self.cx.cache.hidden_cfg = self
130 .cx
131 .tcx
132 .hir()
133 .attrs(CRATE_HIR_ID)
134 .iter()
135 .filter(|attr| attr.has_name(sym::doc))
136 .flat_map(|attr| attr.meta_item_list().into_iter().flatten())
137 .filter(|attr| attr.has_name(sym::cfg_hide))
138 .flat_map(|attr| {
139 attr.meta_item_list()
140 .unwrap_or(&[])
141 .iter()
142 .filter_map(|attr| {
143 Cfg::parse(attr.meta_item()?)
144 .map_err(|e| self.cx.sess().diagnostic().span_err(e.span, e.msg))
145 .ok()
146 })
147 .collect::<Vec<_>>()
148 })
149 .collect();
150
151 self.cx.cache.exact_paths = self.exact_paths;
152 top_level_module
153 }
154
visit_mod_contents( &mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>, name: Symbol, ) -> Module<'tcx>155 fn visit_mod_contents(
156 &mut self,
157 id: hir::HirId,
158 m: &'tcx hir::Mod<'tcx>,
159 name: Symbol,
160 ) -> Module<'tcx> {
161 let mut om = Module::new(name, id, m.inner);
162 let def_id = self.cx.tcx.hir().local_def_id(id).to_def_id();
163 // Keep track of if there were any private modules in the path.
164 let orig_inside_public_path = self.inside_public_path;
165 self.inside_public_path &= self.cx.tcx.visibility(def_id).is_public();
166 for &i in m.item_ids {
167 let item = self.cx.tcx.hir().item(i);
168 self.visit_item(item, None, &mut om);
169 }
170 self.inside_public_path = orig_inside_public_path;
171 om
172 }
173
174 /// Tries to resolve the target of a `pub use` statement and inlines the
175 /// target if it is defined locally and would not be documented otherwise,
176 /// or when it is specifically requested with `please_inline`.
177 /// (the latter is the case when the import is marked `doc(inline)`)
178 ///
179 /// Cross-crate inlining occurs later on during crate cleaning
180 /// and follows different rules.
181 ///
182 /// Returns `true` if the target has been inlined.
maybe_inline_local( &mut self, id: hir::HirId, res: Res, renamed: Option<Symbol>, glob: bool, om: &mut Module<'tcx>, please_inline: bool, ) -> bool183 fn maybe_inline_local(
184 &mut self,
185 id: hir::HirId,
186 res: Res,
187 renamed: Option<Symbol>,
188 glob: bool,
189 om: &mut Module<'tcx>,
190 please_inline: bool,
191 ) -> bool {
192 debug!("maybe_inline_local res: {:?}", res);
193
194 let tcx = self.cx.tcx;
195 let res_did = if let Some(did) = res.opt_def_id() {
196 did
197 } else {
198 return false;
199 };
200
201 let use_attrs = tcx.hir().attrs(id);
202 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
203 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
204 || use_attrs.lists(sym::doc).has_word(sym::hidden);
205
206 // For cross-crate impl inlining we need to know whether items are
207 // reachable in documentation -- a previously unreachable item can be
208 // made reachable by cross-crate inlining which we're checking here.
209 // (this is done here because we need to know this upfront).
210 if !res_did.is_local() && !is_no_inline {
211 let attrs = clean::inline::load_attrs(self.cx, res_did);
212 let self_is_hidden = attrs.lists(sym::doc).has_word(sym::hidden);
213 if !self_is_hidden {
214 if let Res::Def(kind, did) = res {
215 if kind == DefKind::Mod {
216 crate::visit_lib::LibEmbargoVisitor::new(self.cx).visit_mod(did)
217 } else {
218 // All items need to be handled here in case someone wishes to link
219 // to them with intra-doc links
220 self.cx.cache.access_levels.map.insert(did, AccessLevel::Public);
221 }
222 }
223 }
224 return false;
225 }
226
227 let res_hir_id = match res_did.as_local() {
228 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
229 None => return false,
230 };
231
232 let is_private = !self.cx.cache.access_levels.is_public(res_did);
233 let is_hidden = inherits_doc_hidden(self.cx.tcx, res_hir_id);
234
235 // Only inline if requested or if the item would otherwise be stripped.
236 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
237 return false;
238 }
239
240 if !self.view_item_stack.insert(res_hir_id) {
241 return false;
242 }
243
244 let ret = match tcx.hir().get(res_hir_id) {
245 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
246 let prev = mem::replace(&mut self.inlining, true);
247 for &i in m.item_ids {
248 let i = self.cx.tcx.hir().item(i);
249 self.visit_item(i, None, om);
250 }
251 self.inlining = prev;
252 true
253 }
254 Node::Item(it) if !glob => {
255 let prev = mem::replace(&mut self.inlining, true);
256 self.visit_item(it, renamed, om);
257 self.inlining = prev;
258 true
259 }
260 Node::ForeignItem(it) if !glob => {
261 let prev = mem::replace(&mut self.inlining, true);
262 self.visit_foreign_item(it, renamed, om);
263 self.inlining = prev;
264 true
265 }
266 _ => false,
267 };
268 self.view_item_stack.remove(&res_hir_id);
269 ret
270 }
271
visit_item( &mut self, item: &'tcx hir::Item<'_>, renamed: Option<Symbol>, om: &mut Module<'tcx>, )272 fn visit_item(
273 &mut self,
274 item: &'tcx hir::Item<'_>,
275 renamed: Option<Symbol>,
276 om: &mut Module<'tcx>,
277 ) {
278 debug!("visiting item {:?}", item);
279 let name = renamed.unwrap_or(item.ident.name);
280
281 let def_id = item.def_id.to_def_id();
282 let is_pub = self.cx.tcx.visibility(def_id).is_public();
283
284 if is_pub {
285 self.store_path(item.def_id.to_def_id());
286 }
287
288 match item.kind {
289 hir::ItemKind::ForeignMod { items, .. } => {
290 for item in items {
291 let item = self.cx.tcx.hir().foreign_item(item.id);
292 self.visit_foreign_item(item, None, om);
293 }
294 }
295 // If we're inlining, skip private items.
296 _ if self.inlining && !is_pub => {}
297 hir::ItemKind::GlobalAsm(..) => {}
298 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
299 hir::ItemKind::Use(path, kind) => {
300 let is_glob = kind == hir::UseKind::Glob;
301
302 // Struct and variant constructors and proc macro stubs always show up alongside
303 // their definitions, we've already processed them so just discard these.
304 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
305 return;
306 }
307
308 let attrs = self.cx.tcx.hir().attrs(item.hir_id());
309
310 // If there was a private module in the current path then don't bother inlining
311 // anything as it will probably be stripped anyway.
312 if is_pub && self.inside_public_path {
313 let please_inline = attrs.iter().any(|item| match item.meta_item_list() {
314 Some(ref list) if item.has_name(sym::doc) => {
315 list.iter().any(|i| i.has_name(sym::inline))
316 }
317 _ => false,
318 });
319 let ident = if is_glob { None } else { Some(name) };
320 if self.maybe_inline_local(
321 item.hir_id(),
322 path.res,
323 ident,
324 is_glob,
325 om,
326 please_inline,
327 ) {
328 return;
329 }
330 }
331
332 om.items.push((item, renamed))
333 }
334 hir::ItemKind::Macro(ref macro_def) => {
335 // `#[macro_export] macro_rules!` items are handled seperately in `visit()`,
336 // above, since they need to be documented at the module top level. Accordingly,
337 // we only want to handle macros if one of three conditions holds:
338 //
339 // 1. This macro was defined by `macro`, and thus isn't covered by the case
340 // above.
341 // 2. This macro isn't marked with `#[macro_export]`, and thus isn't covered
342 // by the case above.
343 // 3. We're inlining, since a reexport where inlining has been requested
344 // should be inlined even if it is also documented at the top level.
345
346 let def_id = item.def_id.to_def_id();
347 let is_macro_2_0 = !macro_def.macro_rules;
348 let nonexported = !self.cx.tcx.has_attr(def_id, sym::macro_export);
349
350 if is_macro_2_0 || nonexported || self.inlining {
351 om.items.push((item, renamed));
352 }
353 }
354 hir::ItemKind::Mod(ref m) => {
355 om.mods.push(self.visit_mod_contents(item.hir_id(), m, name));
356 }
357 hir::ItemKind::Fn(..)
358 | hir::ItemKind::ExternCrate(..)
359 | hir::ItemKind::Enum(..)
360 | hir::ItemKind::Struct(..)
361 | hir::ItemKind::Union(..)
362 | hir::ItemKind::TyAlias(..)
363 | hir::ItemKind::OpaqueTy(..)
364 | hir::ItemKind::Static(..)
365 | hir::ItemKind::Trait(..)
366 | hir::ItemKind::TraitAlias(..) => om.items.push((item, renamed)),
367 hir::ItemKind::Const(..) => {
368 // Underscore constants do not correspond to a nameable item and
369 // so are never useful in documentation.
370 if name != kw::Underscore {
371 om.items.push((item, renamed));
372 }
373 }
374 hir::ItemKind::Impl(ref impl_) => {
375 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
376 // them up regardless of where they're located.
377 if !self.inlining && impl_.of_trait.is_none() {
378 om.items.push((item, None));
379 }
380 }
381 }
382 }
383
visit_foreign_item( &mut self, item: &'tcx hir::ForeignItem<'_>, renamed: Option<Symbol>, om: &mut Module<'tcx>, )384 fn visit_foreign_item(
385 &mut self,
386 item: &'tcx hir::ForeignItem<'_>,
387 renamed: Option<Symbol>,
388 om: &mut Module<'tcx>,
389 ) {
390 // If inlining we only want to include public functions.
391 if !self.inlining || self.cx.tcx.visibility(item.def_id).is_public() {
392 om.foreigns.push((item, renamed));
393 }
394 }
395 }
396