rustdoc/visit_ast.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614
//! The Rust AST Visitor. Extracts useful information and massages it into a form
//! usable for `clean`.
use std::mem;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId, LocalDefIdSet};
use rustc_hir::intravisit::{Visitor, walk_body, walk_item};
use rustc_hir::{CRATE_HIR_ID, Node};
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::TyCtxt;
use rustc_span::Span;
use rustc_span::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
use rustc_span::hygiene::MacroKind;
use rustc_span::symbol::{Symbol, kw, sym};
use tracing::debug;
use crate::clean::cfg::Cfg;
use crate::clean::utils::{inherits_doc_hidden, should_ignore_res};
use crate::clean::{AttributesExt, NestedAttributesExt, reexport_chain};
use crate::core;
/// This module is used to store stuff from Rust's AST in a more convenient
/// manner (and with prettier names) before cleaning.
#[derive(Debug)]
pub(crate) struct Module<'hir> {
pub(crate) name: Symbol,
pub(crate) where_inner: Span,
pub(crate) mods: Vec<Module<'hir>>,
pub(crate) def_id: LocalDefId,
pub(crate) renamed: Option<Symbol>,
pub(crate) import_id: Option<LocalDefId>,
/// The key is the item `ItemId` and the value is: (item, renamed, import_id).
/// We use `FxIndexMap` to keep the insert order.
pub(crate) items: FxIndexMap<
(LocalDefId, Option<Symbol>),
(&'hir hir::Item<'hir>, Option<Symbol>, Option<LocalDefId>),
>,
/// Same as for `items`.
pub(crate) inlined_foreigns: FxIndexMap<(DefId, Option<Symbol>), (Res, LocalDefId)>,
pub(crate) foreigns: Vec<(&'hir hir::ForeignItem<'hir>, Option<Symbol>)>,
}
impl Module<'_> {
pub(crate) fn new(
name: Symbol,
def_id: LocalDefId,
where_inner: Span,
renamed: Option<Symbol>,
import_id: Option<LocalDefId>,
) -> Self {
Module {
name,
def_id,
where_inner,
renamed,
import_id,
mods: Vec::new(),
items: FxIndexMap::default(),
inlined_foreigns: FxIndexMap::default(),
foreigns: Vec::new(),
}
}
pub(crate) fn where_outer(&self, tcx: TyCtxt<'_>) -> Span {
tcx.def_span(self.def_id)
}
}
// FIXME: Should this be replaced with tcx.def_path_str?
fn def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<Symbol> {
let crate_name = tcx.crate_name(did.krate);
let relative = tcx.def_path(did).data.into_iter().filter_map(|elem| elem.data.get_opt_name());
std::iter::once(crate_name).chain(relative).collect()
}
pub(crate) struct RustdocVisitor<'a, 'tcx> {
cx: &'a mut core::DocContext<'tcx>,
view_item_stack: LocalDefIdSet,
inlining: bool,
/// Are the current module and all of its parents public?
inside_public_path: bool,
exact_paths: DefIdMap<Vec<Symbol>>,
modules: Vec<Module<'tcx>>,
is_importable_from_parent: bool,
inside_body: bool,
}
impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
pub(crate) fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
// If the root is re-exported, terminate all recursion.
let mut stack = LocalDefIdSet::default();
stack.insert(CRATE_DEF_ID);
let om = Module::new(
cx.tcx.crate_name(LOCAL_CRATE),
CRATE_DEF_ID,
cx.tcx.hir().root_module().spans.inner_span,
None,
None,
);
RustdocVisitor {
cx,
view_item_stack: stack,
inlining: false,
inside_public_path: true,
exact_paths: Default::default(),
modules: vec![om],
is_importable_from_parent: true,
inside_body: false,
}
}
fn store_path(&mut self, did: DefId) {
let tcx = self.cx.tcx;
self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
}
pub(crate) fn visit(mut self) -> Module<'tcx> {
let root_module = self.cx.tcx.hir().root_module();
self.visit_mod_contents(CRATE_DEF_ID, root_module);
let mut top_level_module = self.modules.pop().unwrap();
// `#[macro_export] macro_rules!` items are reexported at the top level of the
// crate, regardless of where they're defined. We want to document the
// top level re-export of the macro, not its original definition, since
// the re-export defines the path that a user will actually see. Accordingly,
// we add the re-export as an item here, and then skip over the original
// definition in `visit_item()` below.
//
// We also skip `#[macro_export] macro_rules!` that have already been inserted,
// it can happen if within the same module a `#[macro_export] macro_rules!`
// is declared but also a reexport of itself producing two exports of the same
// macro in the same module.
let mut inserted = FxHashSet::default();
for child in self.cx.tcx.module_children_local(CRATE_DEF_ID) {
if !child.reexport_chain.is_empty()
&& let Res::Def(DefKind::Macro(_), def_id) = child.res
&& let Some(local_def_id) = def_id.as_local()
&& self.cx.tcx.has_attr(def_id, sym::macro_export)
&& inserted.insert(def_id)
{
let item = self.cx.tcx.hir().expect_item(local_def_id);
top_level_module
.items
.insert((local_def_id, Some(item.ident.name)), (item, None, None));
}
}
self.cx.cache.hidden_cfg = self
.cx
.tcx
.hir()
.attrs(CRATE_HIR_ID)
.iter()
.filter(|attr| attr.has_name(sym::doc))
.flat_map(|attr| attr.meta_item_list().into_iter().flatten())
.filter(|attr| attr.has_name(sym::cfg_hide))
.flat_map(|attr| {
attr.meta_item_list()
.unwrap_or(&[])
.iter()
.filter_map(|attr| {
Cfg::parse(attr)
.map_err(|e| self.cx.sess().dcx().span_err(e.span, e.msg))
.ok()
})
.collect::<Vec<_>>()
})
.chain([
Cfg::Cfg(sym::test, None),
Cfg::Cfg(sym::doc, None),
Cfg::Cfg(sym::doctest, None),
])
.collect();
self.cx.cache.exact_paths = self.exact_paths;
top_level_module
}
/// This method will go through the given module items in two passes:
/// 1. The items which are not glob imports/reexports.
/// 2. The glob imports/reexports.
fn visit_mod_contents(&mut self, def_id: LocalDefId, m: &'tcx hir::Mod<'tcx>) {
debug!("Going through module {m:?}");
// Keep track of if there were any private modules in the path.
let orig_inside_public_path = self.inside_public_path;
self.inside_public_path &= self.cx.tcx.local_visibility(def_id).is_public();
// Reimplementation of `walk_mod` because we need to do it in two passes (explanations in
// the second loop):
for &i in m.item_ids {
let item = self.cx.tcx.hir().item(i);
if !matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
self.visit_item(item);
}
}
for &i in m.item_ids {
let item = self.cx.tcx.hir().item(i);
// To match the way import precedence works, visit glob imports last.
// Later passes in rustdoc will de-duplicate by name and kind, so if glob-
// imported items appear last, then they'll be the ones that get discarded.
if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
self.visit_item(item);
}
}
self.inside_public_path = orig_inside_public_path;
debug!("Leaving module {m:?}");
}
/// Tries to resolve the target of a `pub use` statement and inlines the
/// target if it is defined locally and would not be documented otherwise,
/// or when it is specifically requested with `please_inline`.
/// (the latter is the case when the import is marked `doc(inline)`)
///
/// Cross-crate inlining occurs later on during crate cleaning
/// and follows different rules.
///
/// Returns `true` if the target has been inlined.
fn maybe_inline_local(
&mut self,
def_id: LocalDefId,
res: Res,
renamed: Option<Symbol>,
glob: bool,
please_inline: bool,
) -> bool {
debug!("maybe_inline_local (renamed: {renamed:?}) res: {res:?}");
if renamed == Some(kw::Underscore) {
// We never inline `_` reexports.
return false;
}
if self.cx.output_format.is_json() {
return false;
}
let tcx = self.cx.tcx;
let Some(ori_res_did) = res.opt_def_id() else {
return false;
};
let document_hidden = self.cx.render_options.document_hidden;
let use_attrs = tcx.hir().attrs(tcx.local_def_id_to_hir_id(def_id));
// Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
|| (document_hidden && use_attrs.lists(sym::doc).has_word(sym::hidden));
if is_no_inline {
return false;
}
let is_hidden = !document_hidden && tcx.is_doc_hidden(ori_res_did);
let Some(res_did) = ori_res_did.as_local() else {
// For cross-crate impl inlining we need to know whether items are
// reachable in documentation -- a previously unreachable item can be
// made reachable by cross-crate inlining which we're checking here.
// (this is done here because we need to know this upfront).
crate::visit_lib::lib_embargo_visit_item(self.cx, ori_res_did);
if is_hidden || glob {
return false;
}
// We store inlined foreign items otherwise, it'd mean that the `use` item would be kept
// around. It's not a problem unless this `use` imports both a local AND a foreign item.
// If a local item is inlined, its `use` is not supposed to still be around in `clean`,
// which would make appear the `use` in the generated documentation like the local item
// was not inlined even though it actually was.
self.modules
.last_mut()
.unwrap()
.inlined_foreigns
.insert((ori_res_did, renamed), (res, def_id));
return true;
};
let is_private = !self.cx.cache.effective_visibilities.is_directly_public(tcx, ori_res_did);
let item = tcx.hir_node_by_def_id(res_did);
if !please_inline {
let inherits_hidden = !document_hidden && inherits_doc_hidden(tcx, res_did, None);
// Only inline if requested or if the item would otherwise be stripped.
if (!is_private && !inherits_hidden) || (
is_hidden &&
// If it's a doc hidden module, we need to keep it in case some of its inner items
// are re-exported.
!matches!(item, Node::Item(&hir::Item { kind: hir::ItemKind::Mod(_), .. }))
) ||
// The imported item is public and not `doc(hidden)` so no need to inline it.
self.reexport_public_and_not_hidden(def_id, res_did)
{
return false;
}
}
let is_bang_macro = matches!(
item,
Node::Item(&hir::Item { kind: hir::ItemKind::Macro(_, MacroKind::Bang), .. })
);
if !self.view_item_stack.insert(res_did) && !is_bang_macro {
return false;
}
let inlined = match item {
// Bang macros are handled a bit on their because of how they are handled by the
// compiler. If they have `#[doc(hidden)]` and the re-export doesn't have
// `#[doc(inline)]`, then we don't inline it.
Node::Item(_) if is_bang_macro && !please_inline && renamed.is_some() && is_hidden => {
return false;
}
Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
let prev = mem::replace(&mut self.inlining, true);
for &i in m.item_ids {
let i = tcx.hir().item(i);
self.visit_item_inner(i, None, Some(def_id));
}
self.inlining = prev;
true
}
Node::Item(it) if !glob => {
let prev = mem::replace(&mut self.inlining, true);
self.visit_item_inner(it, renamed, Some(def_id));
self.inlining = prev;
true
}
Node::ForeignItem(it) if !glob => {
let prev = mem::replace(&mut self.inlining, true);
self.visit_foreign_item_inner(it, renamed);
self.inlining = prev;
true
}
_ => false,
};
self.view_item_stack.remove(&res_did);
if inlined {
self.cx.cache.inlined_items.insert(ori_res_did);
}
inlined
}
/// Returns `true` if the item is visible, meaning it's not `#[doc(hidden)]` or private.
///
/// This function takes into account the entire re-export `use` chain, so it needs the
/// ID of the "leaf" `use` and the ID of the "root" item.
fn reexport_public_and_not_hidden(
&self,
import_def_id: LocalDefId,
target_def_id: LocalDefId,
) -> bool {
if self.cx.render_options.document_hidden {
return true;
}
let tcx = self.cx.tcx;
let item_def_id = reexport_chain(tcx, import_def_id, target_def_id.to_def_id())
.iter()
.flat_map(|reexport| reexport.id())
.map(|id| id.expect_local())
.nth(1)
.unwrap_or(target_def_id);
item_def_id != import_def_id
&& self.cx.cache.effective_visibilities.is_directly_public(tcx, item_def_id.to_def_id())
&& !tcx.is_doc_hidden(item_def_id)
&& !inherits_doc_hidden(tcx, item_def_id, None)
}
#[inline]
fn add_to_current_mod(
&mut self,
item: &'tcx hir::Item<'_>,
renamed: Option<Symbol>,
parent_id: Option<LocalDefId>,
) {
if self.is_importable_from_parent
// If we're inside an item, only impl blocks and `macro_rules!` with the `macro_export`
// attribute can still be visible.
|| match item.kind {
hir::ItemKind::Impl(..) => true,
hir::ItemKind::Macro(_, MacroKind::Bang) => {
self.cx.tcx.has_attr(item.owner_id.def_id, sym::macro_export)
}
_ => false,
}
{
self.modules
.last_mut()
.unwrap()
.items
.insert((item.owner_id.def_id, renamed), (item, renamed, parent_id));
}
}
fn visit_item_inner(
&mut self,
item: &'tcx hir::Item<'_>,
renamed: Option<Symbol>,
import_id: Option<LocalDefId>,
) {
debug!("visiting item {item:?}");
if self.inside_body {
// Only impls can be "seen" outside a body. For example:
//
// ```
// struct Bar;
//
// fn foo() {
// impl Bar { fn bar() {} }
// }
// Bar::bar();
// ```
if let hir::ItemKind::Impl(impl_) = item.kind &&
// Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
// them up regardless of where they're located.
impl_.of_trait.is_none()
{
self.add_to_current_mod(item, None, None);
}
return;
}
let name = renamed.unwrap_or(item.ident.name);
let tcx = self.cx.tcx;
let def_id = item.owner_id.to_def_id();
let is_pub = tcx.visibility(def_id).is_public();
if is_pub {
self.store_path(item.owner_id.to_def_id());
}
match item.kind {
hir::ItemKind::ForeignMod { items, .. } => {
for item in items {
let item = tcx.hir().foreign_item(item.id);
self.visit_foreign_item_inner(item, None);
}
}
// If we're inlining, skip private items.
_ if self.inlining && !is_pub => {}
hir::ItemKind::GlobalAsm(..) => {}
hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
hir::ItemKind::Use(path, kind) => {
for &res in &path.res {
// Struct and variant constructors and proc macro stubs always show up alongside
// their definitions, we've already processed them so just discard these.
if should_ignore_res(res) {
continue;
}
let attrs = tcx.hir().attrs(tcx.local_def_id_to_hir_id(item.owner_id.def_id));
// If there was a private module in the current path then don't bother inlining
// anything as it will probably be stripped anyway.
if is_pub && self.inside_public_path {
let please_inline = attrs.iter().any(|item| match item.meta_item_list() {
Some(ref list) if item.has_name(sym::doc) => {
list.iter().any(|i| i.has_name(sym::inline))
}
_ => false,
});
let is_glob = kind == hir::UseKind::Glob;
let ident = if is_glob { None } else { Some(name) };
if self.maybe_inline_local(
item.owner_id.def_id,
res,
ident,
is_glob,
please_inline,
) {
debug!("Inlining {:?}", item.owner_id.def_id);
continue;
}
}
self.add_to_current_mod(item, renamed, import_id);
}
}
hir::ItemKind::Macro(ref macro_def, _) => {
// `#[macro_export] macro_rules!` items are handled separately in `visit()`,
// above, since they need to be documented at the module top level. Accordingly,
// we only want to handle macros if one of three conditions holds:
//
// 1. This macro was defined by `macro`, and thus isn't covered by the case
// above.
// 2. This macro isn't marked with `#[macro_export]`, and thus isn't covered
// by the case above.
// 3. We're inlining, since a reexport where inlining has been requested
// should be inlined even if it is also documented at the top level.
let def_id = item.owner_id.to_def_id();
let is_macro_2_0 = !macro_def.macro_rules;
let nonexported = !tcx.has_attr(def_id, sym::macro_export);
if is_macro_2_0 || nonexported || self.inlining {
self.add_to_current_mod(item, renamed, import_id);
}
}
hir::ItemKind::Mod(ref m) => {
self.enter_mod(item.owner_id.def_id, m, name, renamed, import_id);
}
hir::ItemKind::Fn(..)
| hir::ItemKind::ExternCrate(..)
| hir::ItemKind::Enum(..)
| hir::ItemKind::Struct(..)
| hir::ItemKind::Union(..)
| hir::ItemKind::TyAlias(..)
| hir::ItemKind::Static(..)
| hir::ItemKind::Trait(..)
| hir::ItemKind::TraitAlias(..) => {
self.add_to_current_mod(item, renamed, import_id);
}
hir::ItemKind::Const(..) => {
// Underscore constants do not correspond to a nameable item and
// so are never useful in documentation.
if name != kw::Underscore {
self.add_to_current_mod(item, renamed, import_id);
}
}
hir::ItemKind::Impl(impl_) => {
// Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
// them up regardless of where they're located.
if !self.inlining && impl_.of_trait.is_none() {
self.add_to_current_mod(item, None, None);
}
}
}
}
fn visit_foreign_item_inner(
&mut self,
item: &'tcx hir::ForeignItem<'_>,
renamed: Option<Symbol>,
) {
// If inlining we only want to include public functions.
if !self.inlining || self.cx.tcx.visibility(item.owner_id).is_public() {
self.modules.last_mut().unwrap().foreigns.push((item, renamed));
}
}
/// This method will create a new module and push it onto the "modules stack" then call
/// `visit_mod_contents`. Once done, it'll remove it from the "modules stack" and instead
/// add into the list of modules of the current module.
fn enter_mod(
&mut self,
id: LocalDefId,
m: &'tcx hir::Mod<'tcx>,
name: Symbol,
renamed: Option<Symbol>,
import_id: Option<LocalDefId>,
) {
self.modules.push(Module::new(name, id, m.spans.inner_span, renamed, import_id));
self.visit_mod_contents(id, m);
let last = self.modules.pop().unwrap();
self.modules.last_mut().unwrap().mods.push(last);
}
}
// We need to implement this visitor so it'll go everywhere and retrieve items we're interested in
// such as impl blocks in const blocks.
impl<'a, 'tcx> Visitor<'tcx> for RustdocVisitor<'a, 'tcx> {
type NestedFilter = nested_filter::All;
fn nested_visit_map(&mut self) -> Self::Map {
self.cx.tcx.hir()
}
fn visit_item(&mut self, i: &'tcx hir::Item<'tcx>) {
self.visit_item_inner(i, None, None);
let new_value = self.is_importable_from_parent
&& matches!(
i.kind,
hir::ItemKind::Mod(..)
| hir::ItemKind::ForeignMod { .. }
| hir::ItemKind::Impl(..)
| hir::ItemKind::Trait(..)
);
let prev = mem::replace(&mut self.is_importable_from_parent, new_value);
walk_item(self, i);
self.is_importable_from_parent = prev;
}
fn visit_mod(&mut self, _: &hir::Mod<'tcx>, _: Span, _: hir::HirId) {
// Handled in `visit_item_inner`
}
fn visit_use(&mut self, _: &hir::UsePath<'tcx>, _: hir::HirId) {
// Handled in `visit_item_inner`
}
fn visit_path(&mut self, _: &hir::Path<'tcx>, _: hir::HirId) {
// Handled in `visit_item_inner`
}
fn visit_label(&mut self, _: &rustc_ast::Label) {
// Unneeded.
}
fn visit_infer(&mut self, _: &hir::InferArg) {
// Unneeded.
}
fn visit_lifetime(&mut self, _: &hir::Lifetime) {
// Unneeded.
}
fn visit_body(&mut self, b: &hir::Body<'tcx>) {
let prev = mem::replace(&mut self.inside_body, true);
walk_body(self, b);
self.inside_body = prev;
}
}