use crate::clean::{self, PrimitiveType}; use crate::html::sources; use rustc_data_structures::fx::FxHashMap; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::{ExprKind, HirId, 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 std::path::{Path, PathBuf}; /// 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), } /// This function will do at most two things: /// /// 1. Generate a `span` correspondance 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` correspondance map. /// /// Note about the `span` correspondance 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 keep 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, ) -> (FxHashMap, FxHashMap) { let mut visitor = SpanMapVisitor { tcx, matches: FxHashMap::default() }; if include_sources { 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, } 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<'_>) { let info = 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 => Some(def_id), Res::Local(_) => None, Res::PrimTy(p) => { // FIXME: Doesn't handle "path-like" primitives like arrays or tuples. self.matches.insert(path.span, LinkFromSrc::Primitive(PrimitiveType::from(p))); return; } Res::Err => return, _ => return, }; if let Some(span) = self.tcx.hir().res_span(path.res) { self.matches.insert(path.span, LinkFromSrc::Local(clean::Span::new(span))); } else if let Some(def_id) = info { self.matches.insert(path.span, LinkFromSrc::External(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)) } Some(macro_def_id) => 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 } } 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: &'tcx 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 Some(Node::Item(item)) = self.tcx.hir().find(id) { self.matches.insert( item.ident.span, LinkFromSrc::Local(clean::Span::new(m.spans.inner_span)), ); } } intravisit::walk_mod(self, m, id); } fn visit_expr(&mut self, expr: &'tcx rustc_hir::Expr<'tcx>) { if let ExprKind::MethodCall(segment, ..) = expr.kind { let hir = self.tcx.hir(); let body_id = hir.enclosing_body_owner(segment.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.maybe_body_owned_by(body_id).expect("a body which isn't a body")); if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) { self.matches.insert( segment.ident.span, match hir.span_if_local(def_id) { Some(span) => LinkFromSrc::Local(clean::Span::new(span)), None => LinkFromSrc::External(def_id), }, ); } } else if self.handle_macro(expr.span) { // We don't want to go deeper into the macro. return; } intravisit::walk_expr(self, expr); } fn visit_use(&mut self, path: &'tcx rustc_hir::Path<'tcx>, id: HirId) { if self.handle_macro(path.span) { return; } self.handle_path(path); intravisit::walk_use(self, path, id); } }