rustdoc/html/render/span_map.rs
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use std::path::{Path, PathBuf};
use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
use rustc_hir::intravisit::{self, Visitor};
use rustc_hir::{ExprKind, HirId, Item, ItemKind, Mod, Node};
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::TyCtxt;
use rustc_span::hygiene::MacroKind;
use rustc_span::{BytePos, ExpnKind, Span};
use crate::clean::{self, PrimitiveType, rustc_span};
use crate::html::sources;
/// This enum allows us to store two different kinds of information:
///
/// In case the `span` definition comes from the same crate, we can simply get the `span` and use
/// it as is.
///
/// Otherwise, we store the definition `DefId` and will generate a link to the documentation page
/// instead of the source code directly.
#[derive(Debug)]
pub(crate) enum LinkFromSrc {
Local(clean::Span),
External(DefId),
Primitive(PrimitiveType),
Doc(DefId),
}
/// This function will do at most two things:
///
/// 1. Generate a `span` correspondence map which links an item `span` to its definition `span`.
/// 2. Collect the source code files.
///
/// It returns the `krate`, the source code files and the `span` correspondence map.
///
/// Note about the `span` correspondence map: the keys are actually `(lo, hi)` of `span`s. We don't
/// need the `span` context later on, only their position, so instead of keeping a whole `Span`, we
/// only keep the `lo` and `hi`.
pub(crate) fn collect_spans_and_sources(
tcx: TyCtxt<'_>,
krate: &clean::Crate,
src_root: &Path,
include_sources: bool,
generate_link_to_definition: bool,
) -> (FxIndexMap<PathBuf, String>, FxHashMap<Span, LinkFromSrc>) {
if include_sources {
let mut visitor = SpanMapVisitor { tcx, matches: FxHashMap::default() };
if generate_link_to_definition {
tcx.hir().walk_toplevel_module(&mut visitor);
}
let sources = sources::collect_local_sources(tcx, src_root, krate);
(sources, visitor.matches)
} else {
(Default::default(), Default::default())
}
}
struct SpanMapVisitor<'tcx> {
pub(crate) tcx: TyCtxt<'tcx>,
pub(crate) matches: FxHashMap<Span, LinkFromSrc>,
}
impl<'tcx> SpanMapVisitor<'tcx> {
/// This function is where we handle `hir::Path` elements and add them into the "span map".
fn handle_path(&mut self, path: &rustc_hir::Path<'_>) {
match path.res {
// FIXME: For now, we handle `DefKind` if it's not a `DefKind::TyParam`.
// Would be nice to support them too alongside the other `DefKind`
// (such as primitive types!).
Res::Def(kind, def_id) if kind != DefKind::TyParam => {
let link = if def_id.as_local().is_some() {
LinkFromSrc::Local(rustc_span(def_id, self.tcx))
} else {
LinkFromSrc::External(def_id)
};
// In case the path ends with generics, we remove them from the span.
let span = path
.segments
.last()
.map(|last| {
// In `use` statements, the included item is not in the path segments.
// However, it doesn't matter because you can't have generics on `use`
// statements.
if path.span.contains(last.ident.span) {
path.span.with_hi(last.ident.span.hi())
} else {
path.span
}
})
.unwrap_or(path.span);
self.matches.insert(span, link);
}
Res::Local(_) => {
if let Some(span) = self.tcx.hir().res_span(path.res) {
self.matches.insert(path.span, LinkFromSrc::Local(clean::Span::new(span)));
}
}
Res::PrimTy(p) => {
// FIXME: Doesn't handle "path-like" primitives like arrays or tuples.
self.matches.insert(path.span, LinkFromSrc::Primitive(PrimitiveType::from(p)));
}
Res::Err => {}
_ => {}
}
}
/// Used to generate links on items' definition to go to their documentation page.
pub(crate) fn extract_info_from_hir_id(&mut self, hir_id: HirId) {
if let Node::Item(item) = self.tcx.hir_node(hir_id) {
if let Some(span) = self.tcx.def_ident_span(item.owner_id) {
let cspan = clean::Span::new(span);
// If the span isn't from the current crate, we ignore it.
if cspan.inner().is_dummy() || cspan.cnum(self.tcx.sess) != LOCAL_CRATE {
return;
}
self.matches.insert(span, LinkFromSrc::Doc(item.owner_id.to_def_id()));
}
}
}
/// Adds the macro call into the span map. Returns `true` if the `span` was inside a macro
/// expansion, whether or not it was added to the span map.
///
/// The idea for the macro support is to check if the current `Span` comes from expansion. If
/// so, we loop until we find the macro definition by using `outer_expn_data` in a loop.
/// Finally, we get the information about the macro itself (`span` if "local", `DefId`
/// otherwise) and store it inside the span map.
fn handle_macro(&mut self, span: Span) -> bool {
if !span.from_expansion() {
return false;
}
// So if the `span` comes from a macro expansion, we need to get the original
// macro's `DefId`.
let mut data = span.ctxt().outer_expn_data();
let mut call_site = data.call_site;
// Macros can expand to code containing macros, which will in turn be expanded, etc.
// So the idea here is to "go up" until we're back to code that was generated from
// macro expansion so that we can get the `DefId` of the original macro that was at the
// origin of this expansion.
while call_site.from_expansion() {
data = call_site.ctxt().outer_expn_data();
call_site = data.call_site;
}
let macro_name = match data.kind {
ExpnKind::Macro(MacroKind::Bang, macro_name) => macro_name,
// Even though we don't handle this kind of macro, this `data` still comes from
// expansion so we return `true` so we don't go any deeper in this code.
_ => return true,
};
let link_from_src = match data.macro_def_id {
Some(macro_def_id) => {
if macro_def_id.is_local() {
LinkFromSrc::Local(clean::Span::new(data.def_site))
} else {
LinkFromSrc::External(macro_def_id)
}
}
None => return true,
};
let new_span = data.call_site;
let macro_name = macro_name.as_str();
// The "call_site" includes the whole macro with its "arguments". We only want
// the macro name.
let new_span = new_span.with_hi(new_span.lo() + BytePos(macro_name.len() as u32));
self.matches.insert(new_span, link_from_src);
true
}
fn handle_call(&mut self, hir_id: HirId, expr_hir_id: Option<HirId>, span: Span) {
let hir = self.tcx.hir();
let body_id = hir.enclosing_body_owner(hir_id);
// FIXME: this is showing error messages for parts of the code that are not
// compiled (because of cfg)!
//
// See discussion in https://github.com/rust-lang/rust/issues/69426#issuecomment-1019412352
let typeck_results = self.tcx.typeck_body(hir.body_owned_by(body_id).id());
// Interestingly enough, for method calls, we need the whole expression whereas for static
// method/function calls, we need the call expression specifically.
if let Some(def_id) = typeck_results.type_dependent_def_id(expr_hir_id.unwrap_or(hir_id)) {
let link = if def_id.as_local().is_some() {
LinkFromSrc::Local(rustc_span(def_id, self.tcx))
} else {
LinkFromSrc::External(def_id)
};
self.matches.insert(span, link);
}
}
}
impl<'tcx> Visitor<'tcx> for SpanMapVisitor<'tcx> {
type NestedFilter = nested_filter::All;
fn nested_visit_map(&mut self) -> Self::Map {
self.tcx.hir()
}
fn visit_path(&mut self, path: &rustc_hir::Path<'tcx>, _id: HirId) {
if self.handle_macro(path.span) {
return;
}
self.handle_path(path);
intravisit::walk_path(self, path);
}
fn visit_mod(&mut self, m: &'tcx Mod<'tcx>, span: Span, id: HirId) {
// To make the difference between "mod foo {}" and "mod foo;". In case we "import" another
// file, we want to link to it. Otherwise no need to create a link.
if !span.overlaps(m.spans.inner_span) {
// Now that we confirmed it's a file import, we want to get the span for the module
// name only and not all the "mod foo;".
if let Node::Item(item) = self.tcx.hir_node(id) {
self.matches.insert(
item.ident.span,
LinkFromSrc::Local(clean::Span::new(m.spans.inner_span)),
);
}
} else {
// If it's a "mod foo {}", we want to look to its documentation page.
self.extract_info_from_hir_id(id);
}
intravisit::walk_mod(self, m, id);
}
fn visit_expr(&mut self, expr: &'tcx rustc_hir::Expr<'tcx>) {
match expr.kind {
ExprKind::MethodCall(segment, ..) => {
self.handle_call(segment.hir_id, Some(expr.hir_id), segment.ident.span)
}
ExprKind::Call(call, ..) => self.handle_call(call.hir_id, None, call.span),
_ => {
if self.handle_macro(expr.span) {
// We don't want to go deeper into the macro.
return;
}
}
}
intravisit::walk_expr(self, expr);
}
fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
match item.kind {
ItemKind::Static(_, _, _)
| ItemKind::Const(_, _, _)
| ItemKind::Fn(_, _, _)
| ItemKind::Macro(_, _)
| ItemKind::TyAlias(_, _)
| ItemKind::Enum(_, _)
| ItemKind::Struct(_, _)
| ItemKind::Union(_, _)
| ItemKind::Trait(_, _, _, _, _)
| ItemKind::TraitAlias(_, _) => self.extract_info_from_hir_id(item.hir_id()),
ItemKind::Impl(_)
| ItemKind::Use(_, _)
| ItemKind::ExternCrate(_)
| ItemKind::ForeignMod { .. }
| ItemKind::GlobalAsm(_)
// We already have "visit_mod" above so no need to check it here.
| ItemKind::Mod(_) => {}
}
intravisit::walk_item(self, item);
}
}