Skip doc link resolution for some crate types and non-exported items

compiler/rustc_resolve/src/late.rs

@@ -24,13 +24,13 @@ use rustc_hir::{BindingAnnotation, PrimTy, TraitCandidate};
 use rustc_middle::middle::resolve_lifetime::Set1;
 use rustc_middle::ty::DefIdTree;
 use rustc_middle::{bug, span_bug};
-use rustc_session::config::CrateType;
+use rustc_session::config::{CrateType, ResolveDocLinks};
 use rustc_session::lint;
+use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Span, SyntaxContext};
 use smallvec::{smallvec, SmallVec};
 
-use rustc_span::source_map::{respan, Spanned};
 use std::assert_matches::debug_assert_matches;
 use std::borrow::Cow;
 use std::collections::{hash_map::Entry, BTreeSet};
@@ -494,6 +494,30 @@ impl<'a> PathSource<'a> {
     }
 }
 
+/// At this point for most items we can answer whether that item is exported or not,
+/// but some items like impls require type information to determine exported-ness, so we make a
+/// conservative estimate for them (e.g. based on nominal visibility).
+#[derive(Clone, Copy)]
+enum MaybeExported<'a> {
+    Ok(NodeId),
+    Impl(Option<DefId>),
+    ImplItem(Result<DefId, &'a Visibility>),
+}
+
+impl MaybeExported<'_> {
+    fn eval(self, r: &Resolver<'_>) -> bool {
+        let def_id = match self {
+            MaybeExported::Ok(node_id) => Some(r.local_def_id(node_id)),
+            MaybeExported::Impl(Some(trait_def_id)) | MaybeExported::ImplItem(Ok(trait_def_id)) => {
+                trait_def_id.as_local()
+            }
+            MaybeExported::Impl(None) => return true,
+            MaybeExported::ImplItem(Err(vis)) => return vis.kind.is_pub(),
+        };
+        def_id.map_or(true, |def_id| r.effective_visibilities.is_exported(def_id))
+    }
+}
+
 #[derive(Default)]
 struct DiagnosticMetadata<'ast> {
     /// The current trait's associated items' ident, used for diagnostic suggestions.
@@ -774,7 +798,7 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         );
     }
     fn visit_foreign_item(&mut self, foreign_item: &'ast ForeignItem) {
-        self.resolve_doc_links(&foreign_item.attrs);
+        self.resolve_doc_links(&foreign_item.attrs, MaybeExported::Ok(foreign_item.id));
         match foreign_item.kind {
             ForeignItemKind::TyAlias(box TyAlias { ref generics, .. }) => {
                 self.with_generic_param_rib(
@@ -1165,12 +1189,12 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
     }
 
     fn visit_variant(&mut self, v: &'ast Variant) {
-        self.resolve_doc_links(&v.attrs);
+        self.resolve_doc_links(&v.attrs, MaybeExported::Ok(v.id));
         visit::walk_variant(self, v)
     }
 
     fn visit_field_def(&mut self, f: &'ast FieldDef) {
-        self.resolve_doc_links(&f.attrs);
+        self.resolve_doc_links(&f.attrs, MaybeExported::Ok(f.id));
         visit::walk_field_def(self, f)
     }
 }
@@ -2201,8 +2225,8 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     fn resolve_item(&mut self, item: &'ast Item) {
         let mod_inner_docs =
             matches!(item.kind, ItemKind::Mod(..)) && rustdoc::inner_docs(&item.attrs);
-        if !mod_inner_docs {
-            self.resolve_doc_links(&item.attrs);
+        if !mod_inner_docs && !matches!(item.kind, ItemKind::Impl(..)) {
+            self.resolve_doc_links(&item.attrs, MaybeExported::Ok(item.id));
         }
 
         let name = item.ident.name;
@@ -2249,7 +2273,14 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 ..
             }) => {
                 self.diagnostic_metadata.current_impl_items = Some(impl_items);
-                self.resolve_implementation(generics, of_trait, &self_ty, item.id, impl_items);
+                self.resolve_implementation(
+                    &item.attrs,
+                    generics,
+                    of_trait,
+                    &self_ty,
+                    item.id,
+                    impl_items,
+                );
                 self.diagnostic_metadata.current_impl_items = None;
             }
 
@@ -2297,7 +2328,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             ItemKind::Mod(..) => {
                 self.with_scope(item.id, |this| {
                     if mod_inner_docs {
-                        this.resolve_doc_links(&item.attrs);
+                        this.resolve_doc_links(&item.attrs, MaybeExported::Ok(item.id));
                     }
                     let old_macro_rules = this.parent_scope.macro_rules;
                     visit::walk_item(this, item);
@@ -2583,7 +2614,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             };
 
         for item in trait_items {
-            self.resolve_doc_links(&item.attrs);
+            self.resolve_doc_links(&item.attrs, MaybeExported::Ok(item.id));
             match &item.kind {
                 AssocItemKind::Const(_, ty, default) => {
                     self.visit_ty(ty);
@@ -2671,6 +2702,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
     fn resolve_implementation(
         &mut self,
+        attrs: &[ast::Attribute],
         generics: &'ast Generics,
         opt_trait_reference: &'ast Option<TraitRef>,
         self_type: &'ast Ty,
@@ -2701,6 +2733,8 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                                 opt_trait_reference.as_ref(),
                                 self_type,
                                 |this, trait_id| {
+                                    this.resolve_doc_links(attrs, MaybeExported::Impl(trait_id));
+
                                     let item_def_id = this.r.local_def_id(item_id);
 
                                     // Register the trait definitions from here.
@@ -2734,7 +2768,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                                                 debug!("resolve_implementation with_self_rib_ns(ValueNS, ...)");
                                                 let mut seen_trait_items = Default::default();
                                                 for item in impl_items {
-                                                    this.resolve_impl_item(&**item, &mut seen_trait_items);
+                                                    this.resolve_impl_item(&**item, &mut seen_trait_items, trait_id);
                                                 }
                                             });
                                         });
@@ -2752,9 +2786,10 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         &mut self,
         item: &'ast AssocItem,
         seen_trait_items: &mut FxHashMap<DefId, Span>,
+        trait_id: Option<DefId>,
     ) {
         use crate::ResolutionError::*;
-        self.resolve_doc_links(&item.attrs);
+        self.resolve_doc_links(&item.attrs, MaybeExported::ImplItem(trait_id.ok_or(&item.vis)));
         match &item.kind {
             AssocItemKind::Const(_, ty, default) => {
                 debug!("resolve_implementation AssocItemKind::Const");
@@ -4183,7 +4218,23 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         res
     }
 
-    fn resolve_doc_links(&mut self, attrs: &[Attribute]) {
+    fn resolve_doc_links(&mut self, attrs: &[Attribute], maybe_exported: MaybeExported<'_>) {
+        match self.r.session.opts.resolve_doc_links {
+            ResolveDocLinks::None => return,
+            ResolveDocLinks::ExportedMetadata
+                if !self.r.session.crate_types().iter().copied().any(CrateType::has_metadata)
+                    || !maybe_exported.eval(self.r) =>
+            {
+                return;
+            }
+            ResolveDocLinks::Exported if !maybe_exported.eval(self.r) => {
+                return;
+            }
+            ResolveDocLinks::ExportedMetadata
+            | ResolveDocLinks::Exported
+            | ResolveDocLinks::All => {}
+        }
+
         if !attrs.iter().any(|attr| attr.may_have_doc_links()) {
             return;
         }
@@ -4283,7 +4334,7 @@ impl<'a> Resolver<'a> {
     pub(crate) fn late_resolve_crate(&mut self, krate: &Crate) {
         visit::walk_crate(&mut LifetimeCountVisitor { r: self }, krate);
         let mut late_resolution_visitor = LateResolutionVisitor::new(self);
-        late_resolution_visitor.resolve_doc_links(&krate.attrs);
+        late_resolution_visitor.resolve_doc_links(&krate.attrs, MaybeExported::Ok(CRATE_NODE_ID));
         visit::walk_crate(&mut late_resolution_visitor, krate);
         for (id, span) in late_resolution_visitor.diagnostic_metadata.unused_labels.iter() {
             self.lint_buffer.buffer_lint(lint::builtin::UNUSED_LABELS, *id, *span, "unused label");

compiler/rustc_session/src/config.rs

@@ -419,6 +419,18 @@ pub enum TrimmedDefPaths {
     GoodPath,
 }
 
+#[derive(Clone, Hash)]
+pub enum ResolveDocLinks {
+    /// Do not resolve doc links.
+    None,
+    /// Resolve doc links on exported items only for crate types that have metadata.
+    ExportedMetadata,
+    /// Resolve doc links on exported items.
+    Exported,
+    /// Resolve doc links on all items.
+    All,
+}
+
 /// Use tree-based collections to cheaply get a deterministic `Hash` implementation.
 /// *Do not* switch `BTreeMap` out for an unsorted container type! That would break
 /// dependency tracking for command-line arguments. Also only hash keys, since tracking
@@ -788,6 +800,7 @@ impl Default for Options {
             unstable_features: UnstableFeatures::Disallow,
             debug_assertions: true,
             actually_rustdoc: false,
+            resolve_doc_links: ResolveDocLinks::None,
             trimmed_def_paths: TrimmedDefPaths::default(),
             cli_forced_codegen_units: None,
             cli_forced_local_thinlto_off: false,
@@ -883,6 +896,15 @@ pub enum CrateType {
     ProcMacro,
 }
 
+impl CrateType {
+    pub fn has_metadata(self) -> bool {
+        match self {
+            CrateType::Rlib | CrateType::Dylib | CrateType::ProcMacro => true,
+            CrateType::Executable | CrateType::Cdylib | CrateType::Staticlib => false,
+        }
+    }
+}
+
 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
 pub enum Passes {
     Some(Vec<String>),
@@ -2562,6 +2584,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         libs,
         debug_assertions,
         actually_rustdoc: false,
+        resolve_doc_links: ResolveDocLinks::ExportedMetadata,
         trimmed_def_paths: TrimmedDefPaths::default(),
         cli_forced_codegen_units: codegen_units,
         cli_forced_local_thinlto_off: disable_local_thinlto,
@@ -2825,8 +2848,9 @@ pub(crate) mod dep_tracking {
     use super::{
         BranchProtection, CFGuard, CFProtection, CrateType, DebugInfo, ErrorOutputType,
         InstrumentCoverage, InstrumentXRay, LdImpl, LinkerPluginLto, LocationDetail, LtoCli,
-        OomStrategy, OptLevel, OutputType, OutputTypes, Passes, SourceFileHashAlgorithm,
-        SplitDwarfKind, SwitchWithOptPath, SymbolManglingVersion, TraitSolver, TrimmedDefPaths,
+        OomStrategy, OptLevel, OutputType, OutputTypes, Passes, ResolveDocLinks,
+        SourceFileHashAlgorithm, SplitDwarfKind, SwitchWithOptPath, SymbolManglingVersion,
+        TraitSolver, TrimmedDefPaths,
     };
     use crate::lint;
     use crate::options::WasiExecModel;
@@ -2913,6 +2937,7 @@ pub(crate) mod dep_tracking {
         TargetTriple,
         Edition,
         LinkerPluginLto,
+        ResolveDocLinks,
         SplitDebuginfo,
         SplitDwarfKind,
         StackProtector,

compiler/rustc_session/src/options.rs

@@ -169,6 +169,8 @@ top_level_options!(
         /// is currently just a hack and will be removed eventually, so please
         /// try to not rely on this too much.
         actually_rustdoc: bool [TRACKED],
+        /// Whether name resolver should resolve documentation links.
+        resolve_doc_links: ResolveDocLinks [TRACKED],
 
         /// Control path trimming.
         trimmed_def_paths: TrimmedDefPaths [TRACKED],

src/librustdoc/core.rs

@@ -12,7 +12,7 @@ use rustc_hir::{HirId, Path};
 use rustc_interface::interface;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
-use rustc_session::config::{self, CrateType, ErrorOutputType};
+use rustc_session::config::{self, CrateType, ErrorOutputType, ResolveDocLinks};
 use rustc_session::lint;
 use rustc_session::Session;
 use rustc_span::symbol::sym;
@@ -200,6 +200,7 @@ pub(crate) fn create_config(
         scrape_examples_options,
         ..
     }: RustdocOptions,
+    RenderOptions { document_private, .. }: &RenderOptions,
 ) -> rustc_interface::Config {
     // Add the doc cfg into the doc build.
     cfgs.push("doc".to_string());
@@ -227,6 +228,13 @@ pub(crate) fn create_config(
 
     let crate_types =
         if proc_macro_crate { vec![CrateType::ProcMacro] } else { vec![CrateType::Rlib] };
+    let resolve_doc_links = if *document_private {
+        ResolveDocLinks::All
+    } else {
+        // Should be `ResolveDocLinks::Exported` in theory, but for some reason rustdoc
+        // still tries to request resolutions for links on private items.
+        ResolveDocLinks::All
+    };
     let test = scrape_examples_options.map(|opts| opts.scrape_tests).unwrap_or(false);
     // plays with error output here!
     let sessopts = config::Options {
@@ -240,6 +248,7 @@ pub(crate) fn create_config(
         target_triple: target,
         unstable_features: UnstableFeatures::from_environment(crate_name.as_deref()),
         actually_rustdoc: true,
+        resolve_doc_links,
         unstable_opts,
         error_format,
         diagnostic_width,

src/librustdoc/lib.rs

@@ -742,7 +742,7 @@ fn main_args(at_args: &[String]) -> MainResult {
         (false, true) => {
             let input = options.input.clone();
             let edition = options.edition;
-            let config = core::create_config(options);
+            let config = core::create_config(options, &render_options);
 
             // `markdown::render` can invoke `doctest::make_test`, which
             // requires session globals and a thread pool, so we use
@@ -775,7 +775,7 @@ fn main_args(at_args: &[String]) -> MainResult {
     let scrape_examples_options = options.scrape_examples_options.clone();
     let bin_crate = options.bin_crate;
 
-    let config = core::create_config(options);
+    let config = core::create_config(options, &render_options);
 
     interface::run_compiler(config, |compiler| {
         let sess = compiler.session();