1 files changed, 275 insertions, 0 deletions

diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
new file mode 100644
index 000000000..5918b9541
--- /dev/null
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -0,0 +1,275 @@
+//! Maps *syntax* of various definitions to their semantic ids.
+
+use base_db::FileId;
+use hir_def::{
+    child_by_source::ChildBySource,
+    dyn_map::DynMap,
+    expr::PatId,
+    keys::{self, Key},
+    ConstId, DefWithBodyId, EnumId, EnumVariantId, FieldId, FunctionId, GenericDefId, ImplId,
+    ModuleId, StaticId, StructId, TraitId, TypeAliasId, TypeParamId, UnionId, VariantId,
+};
+use hir_expand::{name::AsName, AstId, MacroDefKind};
+use rustc_hash::FxHashMap;
+use stdx::impl_from;
+use syntax::{
+    ast::{self, NameOwner},
+    match_ast, AstNode, SyntaxNode,
+};
+
+use crate::{db::HirDatabase, InFile, MacroDefId};
+
+pub(super) type SourceToDefCache = FxHashMap<ChildContainer, DynMap>;
+
+pub(super) struct SourceToDefCtx<'a, 'b> {
+    pub(super) db: &'b dyn HirDatabase,
+    pub(super) cache: &'a mut SourceToDefCache,
+}
+
+impl SourceToDefCtx<'_, '_> {
+    pub(super) fn file_to_def(&mut self, file: FileId) -> Option<ModuleId> {
+        let _p = profile::span("SourceBinder::to_module_def");
+        let (krate, local_id) = self.db.relevant_crates(file).iter().find_map(|&crate_id| {
+            let crate_def_map = self.db.crate_def_map(crate_id);
+            let local_id = crate_def_map.modules_for_file(file).next()?;
+            Some((crate_id, local_id))
+        })?;
+        Some(ModuleId { krate, local_id })
+    }
+
+    pub(super) fn module_to_def(&mut self, src: InFile<ast::Module>) -> Option<ModuleId> {
+        let _p = profile::span("module_to_def");
+        let parent_declaration = src
+            .as_ref()
+            .map(|it| it.syntax())
+            .cloned()
+            .ancestors_with_macros(self.db.upcast())
+            .skip(1)
+            .find_map(|it| {
+                let m = ast::Module::cast(it.value.clone())?;
+                Some(it.with_value(m))
+            });
+
+        let parent_module = match parent_declaration {
+            Some(parent_declaration) => self.module_to_def(parent_declaration),
+            None => {
+                let file_id = src.file_id.original_file(self.db.upcast());
+                self.file_to_def(file_id)
+            }
+        }?;
+
+        let child_name = src.value.name()?.as_name();
+        let def_map = self.db.crate_def_map(parent_module.krate);
+        let child_id = *def_map[parent_module.local_id].children.get(&child_name)?;
+        Some(ModuleId { krate: parent_module.krate, local_id: child_id })
+    }
+
+    pub(super) fn trait_to_def(&mut self, src: InFile<ast::Trait>) -> Option<TraitId> {
+        self.to_def(src, keys::TRAIT)
+    }
+    pub(super) fn impl_to_def(&mut self, src: InFile<ast::Impl>) -> Option<ImplId> {
+        self.to_def(src, keys::IMPL)
+    }
+    pub(super) fn fn_to_def(&mut self, src: InFile<ast::Fn>) -> Option<FunctionId> {
+        self.to_def(src, keys::FUNCTION)
+    }
+    pub(super) fn struct_to_def(&mut self, src: InFile<ast::Struct>) -> Option<StructId> {
+        self.to_def(src, keys::STRUCT)
+    }
+    pub(super) fn enum_to_def(&mut self, src: InFile<ast::Enum>) -> Option<EnumId> {
+        self.to_def(src, keys::ENUM)
+    }
+    pub(super) fn union_to_def(&mut self, src: InFile<ast::Union>) -> Option<UnionId> {
+        self.to_def(src, keys::UNION)
+    }
+    pub(super) fn static_to_def(&mut self, src: InFile<ast::Static>) -> Option<StaticId> {
+        self.to_def(src, keys::STATIC)
+    }
+    pub(super) fn const_to_def(&mut self, src: InFile<ast::Const>) -> Option<ConstId> {
+        self.to_def(src, keys::CONST)
+    }
+    pub(super) fn type_alias_to_def(&mut self, src: InFile<ast::TypeAlias>) -> Option<TypeAliasId> {
+        self.to_def(src, keys::TYPE_ALIAS)
+    }
+    pub(super) fn record_field_to_def(&mut self, src: InFile<ast::RecordField>) -> Option<FieldId> {
+        self.to_def(src, keys::RECORD_FIELD)
+    }
+    pub(super) fn tuple_field_to_def(&mut self, src: InFile<ast::TupleField>) -> Option<FieldId> {
+        self.to_def(src, keys::TUPLE_FIELD)
+    }
+    pub(super) fn enum_variant_to_def(
+        &mut self,
+        src: InFile<ast::Variant>,
+    ) -> Option<EnumVariantId> {
+        self.to_def(src, keys::VARIANT)
+    }
+    pub(super) fn bind_pat_to_def(
+        &mut self,
+        src: InFile<ast::IdentPat>,
+    ) -> Option<(DefWithBodyId, PatId)> {
+        let container = self.find_pat_container(src.as_ref().map(|it| it.syntax()))?;
+        let (_body, source_map) = self.db.body_with_source_map(container);
+        let src = src.map(ast::Pat::from);
+        let pat_id = source_map.node_pat(src.as_ref())?;
+        Some((container, pat_id))
+    }
+
+    fn to_def<Ast: AstNode + 'static, ID: Copy + 'static>(
+        &mut self,
+        src: InFile<Ast>,
+        key: Key<Ast, ID>,
+    ) -> Option<ID> {
+        let container = self.find_container(src.as_ref().map(|it| it.syntax()))?;
+        let db = self.db;
+        let dyn_map =
+            &*self.cache.entry(container).or_insert_with(|| container.child_by_source(db));
+        dyn_map[key].get(&src).copied()
+    }
+
+    pub(super) fn type_param_to_def(&mut self, src: InFile<ast::TypeParam>) -> Option<TypeParamId> {
+        let container: ChildContainer =
+            self.find_type_param_container(src.as_ref().map(|it| it.syntax()))?.into();
+        let db = self.db;
+        let dyn_map =
+            &*self.cache.entry(container).or_insert_with(|| container.child_by_source(db));
+        dyn_map[keys::TYPE_PARAM].get(&src).copied()
+    }
+
+    // FIXME: use DynMap as well?
+    pub(super) fn macro_call_to_def(&mut self, src: InFile<ast::MacroCall>) -> Option<MacroDefId> {
+        let kind = MacroDefKind::Declarative;
+        let file_id = src.file_id.original_file(self.db.upcast());
+        let krate = self.file_to_def(file_id)?.krate;
+        let file_ast_id = self.db.ast_id_map(src.file_id).ast_id(&src.value);
+        let ast_id = Some(AstId::new(src.file_id, file_ast_id));
+        Some(MacroDefId { krate: Some(krate), ast_id, kind, local_inner: false })
+    }
+
+    pub(super) fn find_container(&mut self, src: InFile<&SyntaxNode>) -> Option<ChildContainer> {
+        for container in src.cloned().ancestors_with_macros(self.db.upcast()).skip(1) {
+            let res: ChildContainer = match_ast! {
+                match (container.value) {
+                    ast::Module(it) => {
+                        let def = self.module_to_def(container.with_value(it))?;
+                        def.into()
+                    },
+                    ast::Trait(it) => {
+                        let def = self.trait_to_def(container.with_value(it))?;
+                        def.into()
+                    },
+                    ast::Impl(it) => {
+                        let def = self.impl_to_def(container.with_value(it))?;
+                        def.into()
+                    },
+                    ast::Fn(it) => {
+                        let def = self.fn_to_def(container.with_value(it))?;
+                        DefWithBodyId::from(def).into()
+                    },
+                    ast::Struct(it) => {
+                        let def = self.struct_to_def(container.with_value(it))?;
+                        VariantId::from(def).into()
+                    },
+                    ast::Enum(it) => {
+                        let def = self.enum_to_def(container.with_value(it))?;
+                        def.into()
+                    },
+                    ast::Union(it) => {
+                        let def = self.union_to_def(container.with_value(it))?;
+                        VariantId::from(def).into()
+                    },
+                    ast::Static(it) => {
+                        let def = self.static_to_def(container.with_value(it))?;
+                        DefWithBodyId::from(def).into()
+                    },
+                    ast::Const(it) => {
+                        let def = self.const_to_def(container.with_value(it))?;
+                        DefWithBodyId::from(def).into()
+                    },
+                    ast::TypeAlias(it) => {
+                        let def = self.type_alias_to_def(container.with_value(it))?;
+                        def.into()
+                    },
+                    _ => continue,
+                }
+            };
+            return Some(res);
+        }
+
+        let def = self.file_to_def(src.file_id.original_file(self.db.upcast()))?;
+        Some(def.into())
+    }
+
+    fn find_type_param_container(&mut self, src: InFile<&SyntaxNode>) -> Option<GenericDefId> {
+        for container in src.cloned().ancestors_with_macros(self.db.upcast()).skip(1) {
+            let res: GenericDefId = match_ast! {
+                match (container.value) {
+                    ast::Fn(it) => self.fn_to_def(container.with_value(it))?.into(),
+                    ast::Struct(it) => self.struct_to_def(container.with_value(it))?.into(),
+                    ast::Enum(it) => self.enum_to_def(container.with_value(it))?.into(),
+                    ast::Trait(it) => self.trait_to_def(container.with_value(it))?.into(),
+                    ast::TypeAlias(it) => self.type_alias_to_def(container.with_value(it))?.into(),
+                    ast::Impl(it) => self.impl_to_def(container.with_value(it))?.into(),
+                    _ => continue,
+                }
+            };
+            return Some(res);
+        }
+        None
+    }
+
+    fn find_pat_container(&mut self, src: InFile<&SyntaxNode>) -> Option<DefWithBodyId> {
+        for container in src.cloned().ancestors_with_macros(self.db.upcast()).skip(1) {
+            let res: DefWithBodyId = match_ast! {
+                match (container.value) {
+                    ast::Const(it) => self.const_to_def(container.with_value(it))?.into(),
+                    ast::Static(it) => self.static_to_def(container.with_value(it))?.into(),
+                    ast::Fn(it) => self.fn_to_def(container.with_value(it))?.into(),
+                    _ => continue,
+                }
+            };
+            return Some(res);
+        }
+        None
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+pub(crate) enum ChildContainer {
+    DefWithBodyId(DefWithBodyId),
+    ModuleId(ModuleId),
+    TraitId(TraitId),
+    ImplId(ImplId),
+    EnumId(EnumId),
+    VariantId(VariantId),
+    TypeAliasId(TypeAliasId),
+    /// XXX: this might be the same def as, for example an `EnumId`. However,
+    /// here the children generic parameters, and not, eg enum variants.
+    GenericDefId(GenericDefId),
+}
+impl_from! {
+    DefWithBodyId,
+    ModuleId,
+    TraitId,
+    ImplId,
+    EnumId,
+    VariantId,
+    TypeAliasId,
+    GenericDefId
+    for ChildContainer
+}
+
+impl ChildContainer {
+    fn child_by_source(self, db: &dyn HirDatabase) -> DynMap {
+        let db = db.upcast();
+        match self {
+            ChildContainer::DefWithBodyId(it) => it.child_by_source(db),
+            ChildContainer::ModuleId(it) => it.child_by_source(db),
+            ChildContainer::TraitId(it) => it.child_by_source(db),
+            ChildContainer::ImplId(it) => it.child_by_source(db),
+            ChildContainer::EnumId(it) => it.child_by_source(db),
+            ChildContainer::VariantId(it) => it.child_by_source(db),
+            ChildContainer::TypeAliasId(_) => DynMap::default(),
+            ChildContainer::GenericDefId(it) => it.child_by_source(db),
+        }
+    }
+}