Rollup merge of rust-lang#143657 - LorrensP-2158466:split-macro-map, r=petrochenkov

Resolver: refact macro map into external and local maps

Puts `MacroData` inside of the `ResolverArena` and splits `macro_map` into 2 maps: `local_macro_map` and `external_macro_map`. This way `get_macro_by_def_id` can take a `&Resolver` instead of a mutable one.

Part of [#gsoc > Project: Parallel Macro Expansion](https://rust-lang.zulipchat.com/#narrow/channel/421156-gsoc/topic/Project.3A.20Parallel.20Macro.20Expansion/with/516965603)

r? `@petrochenkov`

Author: matthiaskrgr

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -162,28 +162,30 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
-    pub(crate) fn get_macro(&mut self, res: Res) -> Option<&MacroData> {
+    pub(crate) fn get_macro(&self, res: Res) -> Option<&'ra MacroData> {
         match res {
             Res::Def(DefKind::Macro(..), def_id) => Some(self.get_macro_by_def_id(def_id)),
-            Res::NonMacroAttr(_) => Some(&self.non_macro_attr),
+            Res::NonMacroAttr(_) => Some(self.non_macro_attr),
             _ => None,
         }
     }
 
-    pub(crate) fn get_macro_by_def_id(&mut self, def_id: DefId) -> &MacroData {
-        if self.macro_map.contains_key(&def_id) {
-            return &self.macro_map[&def_id];
-        }
-
-        let loaded_macro = self.cstore().load_macro_untracked(def_id, self.tcx);
-        let macro_data = match loaded_macro {
-            LoadedMacro::MacroDef { def, ident, attrs, span, edition } => {
-                self.compile_macro(&def, ident, &attrs, span, ast::DUMMY_NODE_ID, edition)
-            }
-            LoadedMacro::ProcMacro(ext) => MacroData::new(Arc::new(ext)),
-        };
+    pub(crate) fn get_macro_by_def_id(&self, def_id: DefId) -> &'ra MacroData {
+        // Local macros are always compiled.
+        match def_id.as_local() {
+            Some(local_def_id) => self.local_macro_map[&local_def_id],
+            None => *self.extern_macro_map.borrow_mut().entry(def_id).or_insert_with(|| {
+                let loaded_macro = self.cstore().load_macro_untracked(def_id, self.tcx);
+                let macro_data = match loaded_macro {
+                    LoadedMacro::MacroDef { def, ident, attrs, span, edition } => {
+                        self.compile_macro(&def, ident, &attrs, span, ast::DUMMY_NODE_ID, edition)
+                    }
+                    LoadedMacro::ProcMacro(ext) => MacroData::new(Arc::new(ext)),
+                };
 
-        self.macro_map.entry(def_id).or_insert(macro_data)
+                self.arenas.alloc_macro(macro_data)
+            }),
+        }
     }
 
     pub(crate) fn build_reduced_graph(
@@ -1203,7 +1205,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
     fn insert_unused_macro(&mut self, ident: Ident, def_id: LocalDefId, node_id: NodeId) {
         if !ident.as_str().starts_with('_') {
             self.r.unused_macros.insert(def_id, (node_id, ident));
-            let nrules = self.r.macro_map[&def_id.to_def_id()].nrules;
+            let nrules = self.r.local_macro_map[&def_id].nrules;
             self.r.unused_macro_rules.insert(node_id, DenseBitSet::new_filled(nrules));
         }
     }
@@ -1222,7 +1224,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
                     Some((macro_kind, ident, span)) => {
                         let res = Res::Def(DefKind::Macro(macro_kind), def_id.to_def_id());
                         let macro_data = MacroData::new(self.r.dummy_ext(macro_kind));
-                        self.r.macro_map.insert(def_id.to_def_id(), macro_data);
+                        self.r.new_local_macro(def_id, macro_data);
                         self.r.proc_macro_stubs.insert(def_id);
                         (res, ident, span, false)
                     }

compiler/rustc_resolve/src/def_collector.rs

@@ -165,7 +165,7 @@ impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
             self.create_def(i.id, i.kind.ident().map(|ident| ident.name), def_kind, i.span);
 
         if let Some(macro_data) = opt_macro_data {
-            self.resolver.macro_map.insert(def_id.to_def_id(), macro_data);
+            self.resolver.new_local_macro(def_id, macro_data);
         }
 
         self.with_parent(def_id, |this| {

compiler/rustc_resolve/src/diagnostics.rs

@@ -1669,9 +1669,14 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         let mut all_attrs: UnordMap<Symbol, Vec<_>> = UnordMap::default();
         // We're collecting these in a hashmap, and handle ordering the output further down.
         #[allow(rustc::potential_query_instability)]
-        for (def_id, data) in &self.macro_map {
+        for (def_id, data) in self
+            .local_macro_map
+            .iter()
+            .map(|(local_id, data)| (local_id.to_def_id(), data))
+            .chain(self.extern_macro_map.borrow().iter().map(|(id, d)| (*id, d)))
+        {
             for helper_attr in &data.ext.helper_attrs {
-                let item_name = self.tcx.item_name(*def_id);
+                let item_name = self.tcx.item_name(def_id);
                 all_attrs.entry(*helper_attr).or_default().push(item_name);
                 if helper_attr == &ident.name {
                     derives.push(item_name);

compiler/rustc_resolve/src/lib.rs

@@ -1128,10 +1128,12 @@ pub struct Resolver<'ra, 'tcx> {
     builtin_macros: FxHashMap<Symbol, SyntaxExtensionKind>,
     registered_tools: &'tcx RegisteredTools,
     macro_use_prelude: FxIndexMap<Symbol, NameBinding<'ra>>,
-    macro_map: FxHashMap<DefId, MacroData>,
+    local_macro_map: FxHashMap<LocalDefId, &'ra MacroData>,
+    /// Lazily populated cache of macros loaded from external crates.
+    extern_macro_map: RefCell<FxHashMap<DefId, &'ra MacroData>>,
     dummy_ext_bang: Arc<SyntaxExtension>,
     dummy_ext_derive: Arc<SyntaxExtension>,
-    non_macro_attr: MacroData,
+    non_macro_attr: &'ra MacroData,
     local_macro_def_scopes: FxHashMap<LocalDefId, Module<'ra>>,
     ast_transform_scopes: FxHashMap<LocalExpnId, Module<'ra>>,
     unused_macros: FxIndexMap<LocalDefId, (NodeId, Ident)>,
@@ -1241,6 +1243,7 @@ pub struct ResolverArenas<'ra> {
     imports: TypedArena<ImportData<'ra>>,
     name_resolutions: TypedArena<RefCell<NameResolution<'ra>>>,
     ast_paths: TypedArena<ast::Path>,
+    macros: TypedArena<MacroData>,
     dropless: DroplessArena,
 }
 
@@ -1287,7 +1290,7 @@ impl<'ra> ResolverArenas<'ra> {
         self.name_resolutions.alloc(Default::default())
     }
     fn alloc_macro_rules_scope(&'ra self, scope: MacroRulesScope<'ra>) -> MacroRulesScopeRef<'ra> {
-        Interned::new_unchecked(self.dropless.alloc(Cell::new(scope)))
+        self.dropless.alloc(Cell::new(scope))
     }
     fn alloc_macro_rules_binding(
         &'ra self,
@@ -1298,6 +1301,9 @@ impl<'ra> ResolverArenas<'ra> {
     fn alloc_ast_paths(&'ra self, paths: &[ast::Path]) -> &'ra [ast::Path] {
         self.ast_paths.alloc_from_iter(paths.iter().cloned())
     }
+    fn alloc_macro(&'ra self, macro_data: MacroData) -> &'ra MacroData {
+        self.macros.alloc(macro_data)
+    }
     fn alloc_pattern_spans(&'ra self, spans: impl Iterator<Item = Span>) -> &'ra [Span] {
         self.dropless.alloc_from_iter(spans)
     }
@@ -1540,10 +1546,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             builtin_macros: Default::default(),
             registered_tools,
             macro_use_prelude: Default::default(),
-            macro_map: FxHashMap::default(),
+            local_macro_map: Default::default(),
+            extern_macro_map: Default::default(),
             dummy_ext_bang: Arc::new(SyntaxExtension::dummy_bang(edition)),
             dummy_ext_derive: Arc::new(SyntaxExtension::dummy_derive(edition)),
-            non_macro_attr: MacroData::new(Arc::new(SyntaxExtension::non_macro_attr(edition))),
+            non_macro_attr: arenas
+                .alloc_macro(MacroData::new(Arc::new(SyntaxExtension::non_macro_attr(edition)))),
             invocation_parent_scopes: Default::default(),
             output_macro_rules_scopes: Default::default(),
             macro_rules_scopes: Default::default(),
@@ -1616,6 +1624,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         )
     }
 
+    fn new_local_macro(&mut self, def_id: LocalDefId, macro_data: MacroData) -> &'ra MacroData {
+        let mac = self.arenas.alloc_macro(macro_data);
+        self.local_macro_map.insert(def_id, mac);
+        mac
+    }
+
     fn next_node_id(&mut self) -> NodeId {
         let start = self.next_node_id;
         let next = start.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
@@ -1734,7 +1748,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         f(self, MacroNS);
     }
 
-    fn is_builtin_macro(&mut self, res: Res) -> bool {
+    fn is_builtin_macro(&self, res: Res) -> bool {
         self.get_macro(res).is_some_and(|macro_data| macro_data.ext.builtin_name.is_some())
     }
 

compiler/rustc_resolve/src/macros.rs

@@ -9,7 +9,6 @@ use rustc_ast::expand::StrippedCfgItem;
 use rustc_ast::{self as ast, Crate, NodeId, attr};
 use rustc_ast_pretty::pprust;
 use rustc_attr_data_structures::StabilityLevel;
-use rustc_data_structures::intern::Interned;
 use rustc_errors::{Applicability, DiagCtxtHandle, StashKey};
 use rustc_expand::base::{
     Annotatable, DeriveResolution, Indeterminate, ResolverExpand, SyntaxExtension,
@@ -80,7 +79,7 @@ pub(crate) enum MacroRulesScope<'ra> {
 /// This helps to avoid uncontrollable growth of `macro_rules!` scope chains,
 /// which usually grow linearly with the number of macro invocations
 /// in a module (including derives) and hurt performance.
-pub(crate) type MacroRulesScopeRef<'ra> = Interned<'ra, Cell<MacroRulesScope<'ra>>>;
+pub(crate) type MacroRulesScopeRef<'ra> = &'ra Cell<MacroRulesScope<'ra>>;
 
 /// Macro namespace is separated into two sub-namespaces, one for bang macros and
 /// one for attribute-like macros (attributes, derives).
@@ -354,8 +353,8 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
             if unused_arms.is_empty() {
                 continue;
             }
-            let def_id = self.local_def_id(node_id).to_def_id();
-            let m = &self.macro_map[&def_id];
+            let def_id = self.local_def_id(node_id);
+            let m = &self.local_macro_map[&def_id];
             let SyntaxExtensionKind::LegacyBang(ref ext) = m.ext.kind else {
                 continue;
             };
@@ -1132,7 +1131,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
-    pub(crate) fn check_reserved_macro_name(&mut self, ident: Ident, res: Res) {
+    pub(crate) fn check_reserved_macro_name(&self, ident: Ident, res: Res) {
         // Reserve some names that are not quite covered by the general check
         // performed on `Resolver::builtin_attrs`.
         if ident.name == sym::cfg || ident.name == sym::cfg_attr {
@@ -1148,7 +1147,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     ///
     /// Possibly replace its expander to a pre-defined one for built-in macros.
     pub(crate) fn compile_macro(
-        &mut self,
+        &self,
         macro_def: &ast::MacroDef,
         ident: Ident,
         attrs: &[rustc_hir::Attribute],