Split `Importer` into individual classes for each decl type.
This is one step towards a more query-based importer architecture, by
encapsulating the individual import methods and extracting an interface for
their interaction with the importer.
The extracted interfaces of the `DeclImporter` and `ImportContext` are not meant
to be permanent. They merely extract the status quo and provide a basis for
future improvements.
I also plan on moving individual `DeclImporter`s into their own files. Maybe
also the `Invocation` and the `ImportContext`. I haven't done that in this CL to
make review easier.
PiperOrigin-RevId: 443642590
diff --git a/rs_bindings_from_cc/importer.h b/rs_bindings_from_cc/importer.h
index 50aa64e..c2824c8 100644
--- a/rs_bindings_from_cc/importer.h
+++ b/rs_bindings_from_cc/importer.h
@@ -33,154 +33,133 @@
namespace crubit {
-// Iterates over the AST created from the invocation's entry headers and
-// creates an intermediate representation of the import (`IR`) into the
-// invocation object.
-class Importer {
+// Top-level parameters as well as return value of an importer invocation.
+class Invocation {
public:
- // Top-level parameters as well as return value of an importer invocation.
- class Invocation {
- public:
- Invocation(BazelLabel target, absl::Span<const HeaderName> entry_headers,
- const absl::flat_hash_map<const HeaderName, const BazelLabel>&
- header_targets)
- : target_(target),
- entry_headers_(entry_headers),
- lifetime_context_(
- std::make_shared<
- clang::tidy::lifetimes::LifetimeAnnotationContext>()),
- header_targets_(header_targets) {
- // Caller should verify that the inputs are non-empty.
- CRUBIT_CHECK(!entry_headers_.empty());
- CRUBIT_CHECK(!header_targets_.empty());
+ Invocation(BazelLabel target, absl::Span<const HeaderName> entry_headers,
+ const absl::flat_hash_map<const HeaderName, const BazelLabel>&
+ header_targets)
+ : target_(target),
+ entry_headers_(entry_headers),
+ lifetime_context_(std::make_shared<
+ clang::tidy::lifetimes::LifetimeAnnotationContext>()),
+ header_targets_(header_targets) {
+ // Caller should verify that the inputs are non-empty.
+ CRUBIT_CHECK(!entry_headers_.empty());
+ CRUBIT_CHECK(!header_targets_.empty());
- ir_.used_headers.insert(ir_.used_headers.end(), entry_headers_.begin(),
- entry_headers.end());
- ir_.current_target = target_;
- }
+ ir_.used_headers.insert(ir_.used_headers.end(), entry_headers_.begin(),
+ entry_headers.end());
+ ir_.current_target = target_;
+ }
- // Returns the target of a header, if any.
- std::optional<BazelLabel> header_target(const HeaderName header) const {
- auto it = header_targets_.find(header);
- return (it != header_targets_.end()) ? std::optional(it->second)
- : std::nullopt;
- }
+ // Returns the target of a header, if any.
+ std::optional<BazelLabel> header_target(const HeaderName header) const {
+ auto it = header_targets_.find(header);
+ return (it != header_targets_.end()) ? std::optional(it->second)
+ : std::nullopt;
+ }
- // The main target from which we are importing.
- const BazelLabel target_;
+ // The main target from which we are importing.
+ const BazelLabel target_;
- // The headers from which the import starts (a collection of
- // paths in the format suitable for a google3-relative quote include).
- const absl::Span<const HeaderName> entry_headers_;
+ // The headers from which the import starts (a collection of
+ // paths in the format suitable for a google3-relative quote include).
+ const absl::Span<const HeaderName> entry_headers_;
- const std::shared_ptr<clang::tidy::lifetimes::LifetimeAnnotationContext>
- lifetime_context_;
+ const std::shared_ptr<clang::tidy::lifetimes::LifetimeAnnotationContext>
+ lifetime_context_;
- // The main output of the import process
- IR ir_;
-
- private:
- const absl::flat_hash_map<const HeaderName, const BazelLabel>&
- header_targets_;
- };
-
- // The currently known canonical type decls that we know how to map into
- // Rust.
- class TypeMapper {
- public:
- TypeMapper(const clang::ASTContext* ctx) : ctx_(ctx) {}
-
- TypeMapper(const TypeMapper& other) = default;
- TypeMapper& operator=(const TypeMapper& other) = default;
-
- // Converts the Clang type `qual_type` into an equivalent `MappedType`.
- // Lifetimes for the type can optionally be specified using `lifetimes`.
- // If `qual_type` is a pointer type, `nullable` specifies whether the
- // pointer can be null.
- // TODO(b/209390498): Currently, we're able to specify nullability only for
- // top-level pointers. Extend this so that we can specify nullability for
- // all pointers contained in `qual_type`, in the same way that `lifetimes`
- // specifies lifetimes for all these pointers. Once this is done, make sure
- // that all callers pass in the appropriate information, derived from
- // nullability annotations.
- absl::StatusOr<MappedType> ConvertQualType(
- clang::QualType qual_type,
- std::optional<clang::tidy::lifetimes::ValueLifetimes>& lifetimes,
- bool nullable = true) const;
- absl::StatusOr<MappedType> ConvertType(
- const clang::Type* type,
- std::optional<clang::tidy::lifetimes::ValueLifetimes>& lifetimes,
- bool nullable) const;
- absl::StatusOr<MappedType> ConvertTypeDecl(
- const clang::TypeDecl* decl) const;
-
- bool Contains(const clang::TypeDecl* decl) const {
- return known_type_decls_.contains(
- clang::cast<clang::TypeDecl>(decl->getCanonicalDecl()));
- }
-
- void Insert(const clang::TypeDecl* decl) {
- known_type_decls_.insert(
- clang::cast<clang::TypeDecl>(decl->getCanonicalDecl()));
- }
-
- private:
- const clang::ASTContext* ctx_;
- absl::flat_hash_set<const clang::TypeDecl*> known_type_decls_;
- };
-
- explicit Importer(Invocation& invocation, clang::ASTContext& ctx,
- clang::Sema& sema)
- : invocation_(invocation),
- ctx_(ctx),
- sema_(sema),
- mangler_(CRUBIT_DIE_IF_NULL(ctx_.createMangleContext())),
- type_mapper_(&ctx) {}
-
- // Import all visible declarations from a translation unit.
- void Import(clang::TranslationUnitDecl* decl);
+ // The main output of the import process
+ IR ir_;
private:
+ const absl::flat_hash_map<const HeaderName, const BazelLabel>&
+ header_targets_;
+};
+
+// The currently known canonical type decls that we know how to map into
+// Rust.
+class TypeMapper {
+ public:
+ TypeMapper(const clang::ASTContext* ctx) : ctx_(ctx) {}
+
+ TypeMapper(const TypeMapper& other) = default;
+ TypeMapper& operator=(const TypeMapper& other) = default;
+
+ // Converts the Clang type `qual_type` into an equivalent `MappedType`.
+ // Lifetimes for the type can optionally be specified using `lifetimes`.
+ // If `qual_type` is a pointer type, `nullable` specifies whether the
+ // pointer can be null.
+ // TODO(b/209390498): Currently, we're able to specify nullability only for
+ // top-level pointers. Extend this so that we can specify nullability for
+ // all pointers contained in `qual_type`, in the same way that `lifetimes`
+ // specifies lifetimes for all these pointers. Once this is done, make sure
+ // that all callers pass in the appropriate information, derived from
+ // nullability annotations.
+ absl::StatusOr<MappedType> ConvertQualType(
+ clang::QualType qual_type,
+ std::optional<clang::tidy::lifetimes::ValueLifetimes>& lifetimes,
+ bool nullable = true) const;
+ absl::StatusOr<MappedType> ConvertType(
+ const clang::Type* type,
+ std::optional<clang::tidy::lifetimes::ValueLifetimes>& lifetimes,
+ bool nullable) const;
+ absl::StatusOr<MappedType> ConvertTypeDecl(const clang::TypeDecl* decl) const;
+ std::optional<absl::string_view> MapKnownCcTypeToRsType(
+ absl::string_view cc_type) const;
+
+ bool Contains(const clang::TypeDecl* decl) const {
+ return known_type_decls_.contains(
+ clang::cast<clang::TypeDecl>(decl->getCanonicalDecl()));
+ }
+
+ void Insert(const clang::TypeDecl* decl) {
+ known_type_decls_.insert(
+ clang::cast<clang::TypeDecl>(decl->getCanonicalDecl()));
+ }
+
+ private:
+ const clang::ASTContext* ctx_;
+ absl::flat_hash_set<const clang::TypeDecl*> known_type_decls_;
+};
+
+// Explicitly defined interface that defines how `DeclImporter`s are allowed to
+// interface with the global state of the importer.
+class ImportContext {
+ public:
+ ImportContext(Invocation& invocation, clang::ASTContext& ctx,
+ clang::Sema& sema)
+ : invocation_(invocation), ctx_(ctx), sema_(sema), type_mapper_(&ctx){};
+ virtual ~ImportContext(){};
+
// Imports all decls contained in a `DeclContext`.
- void ImportDeclsFromDeclContext(const clang::DeclContext* decl_context);
+ virtual void ImportDeclsFromDeclContext(
+ const clang::DeclContext* decl_context) = 0;
- // Returns the Item of a Decl, importing it first if necessary.
- std::optional<IR::Item> GetDeclItem(clang::Decl* decl);
+ // Imports an unsupported item with a single error message.
+ virtual IR::Item ImportUnsupportedItem(const clang::Decl* decl,
+ std::string error) = 0;
- // Imports a decl and creates an IR item (or error messages).
- // Does not use or update the cache.
- std::optional<IR::Item> ImportDecl(clang::Decl* decl);
+ // Imports an unsupported item with multiple error messages.
+ virtual IR::Item ImportUnsupportedItem(const clang::Decl* decl,
+ std::set<std::string> errors) = 0;
- // These functions import specific `Decl` subtypes. They use `LookupDecl` to
- // lookup dependencies. They don't use or update the cache themselves.
- std::optional<IR::Item> ImportNamespace(clang::NamespaceDecl* namespace_decl);
- std::optional<IR::Item> ImportFunction(
- clang::FunctionDecl* function_decl,
- clang::FunctionTemplateDecl* function_template_decl = nullptr);
- std::optional<IR::Item> ImportRecord(clang::CXXRecordDecl* record_decl);
- std::optional<IR::Item> ImportTypedefName(
- clang::TypedefNameDecl* typedef_name_decl);
- std::optional<IR::Item> ImportEnum(clang::EnumDecl* enum_decl);
-
- IR::Item ImportUnsupportedItem(const clang::Decl* decl, std::string error);
- IR::Item ImportUnsupportedItem(const clang::Decl* decl,
- std::set<std::string> errors);
-
- absl::StatusOr<std::vector<Field>> ImportFields(
- clang::CXXRecordDecl* record_decl);
- // Stores the comments of this target in source order.
- void ImportFreeComments();
// Returns the item ids of the children and comments of the given decl in
// source order. This method assumes that the children decls have already been
// imported.
- std::vector<ItemId> GetItemIdsInSourceOrder(clang::Decl* decl);
+ virtual std::vector<ItemId> GetItemIdsInSourceOrder(clang::Decl* decl) = 0;
- std::string GetMangledName(const clang::NamedDecl* named_decl) const;
- BazelLabel GetOwningTarget(const clang::Decl* decl) const;
+ // Mangles the name of a named decl.
+ virtual std::string GetMangledName(
+ const clang::NamedDecl* named_decl) const = 0;
+
+ // Returs the label of the target that contains a decl.
+ virtual BazelLabel GetOwningTarget(const clang::Decl* decl) const = 0;
// Checks if the given decl belongs to the current target. Does not look into
// other redeclarations of the decl.
- bool IsFromCurrentTarget(const clang::Decl* decl) const;
+ virtual bool IsFromCurrentTarget(const clang::Decl* decl) const = 0;
// Gets an IR UnqualifiedIdentifier for the named decl.
//
@@ -190,36 +169,184 @@
// a SpecialName.
//
// If the translated name is not yet implemented, this returns null.
- std::optional<UnqualifiedIdentifier> GetTranslatedName(
- const clang::NamedDecl* named_decl) const;
+ virtual std::optional<UnqualifiedIdentifier> GetTranslatedName(
+ const clang::NamedDecl* named_decl) const = 0;
// GetTranslatedName, but only for identifier names. This is the common case.
+ virtual std::optional<Identifier> GetTranslatedIdentifier(
+ const clang::NamedDecl* named_decl) const = 0;
+
+ // Gets the doc comment of the declaration.
+ virtual llvm::Optional<std::string> GetComment(
+ const clang::Decl* decl) const = 0;
+
+ // Converts a Clang source location to IR.
+ virtual SourceLoc ConvertSourceLocation(clang::SourceLocation loc) const = 0;
+
+ Invocation& invocation_;
+ clang::ASTContext& ctx_;
+ clang::Sema& sema_;
+ TypeMapper type_mapper_;
+};
+
+// Interface for components that can import decls of a certain category.
+class DeclImporter {
+ public:
+ DeclImporter(ImportContext& ictx) : ictx_(ictx){};
+ virtual ~DeclImporter(){};
+
+ // Determines whether this importer is autoritative for a decl. This does not
+ // imply that the import will be succesful.
+ virtual bool CanImport(clang::Decl*) = 0;
+
+ // Returns an IR item for a decl, or `std::nullopt` if importing failed.
+ // This member function may only be called after `CanImport` returned `true`.
+ virtual std::optional<IR::Item> ImportDecl(clang::Decl*) = 0;
+
+ protected:
+ ImportContext& ictx_;
+};
+
+// Common implementation for defining `DeclImporter`s that determine their
+// applicability by the dynamic type of the decl.
+template <typename D>
+class DeclImporterBase : public DeclImporter {
+ public:
+ DeclImporterBase(ImportContext& context) : DeclImporter(context) {}
+
+ protected:
+ bool CanImport(clang::Decl* decl) { return clang::isa<D>(decl); }
+ std::optional<IR::Item> ImportDecl(clang::Decl* decl) {
+ return Import(clang::cast<D>(decl));
+ }
+ virtual std::optional<IR::Item> Import(D*);
+};
+
+// TODO(forster): Move those implementations into separate files.
+
+// A `DeclImporter` for `ClassTemplateDecl`s.
+class ClassTemplateDeclImporter
+ : public DeclImporterBase<clang::ClassTemplateDecl> {
+ public:
+ ClassTemplateDeclImporter(ImportContext& context)
+ : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::ClassTemplateDecl*);
+};
+
+// A `DeclImporter` for `CXXRecordDecl`s.
+class CXXRecordDeclImporter : public DeclImporterBase<clang::CXXRecordDecl> {
+ public:
+ CXXRecordDeclImporter(ImportContext& context) : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::CXXRecordDecl*);
+
+ private:
+ absl::StatusOr<std::vector<Field>> ImportFields(clang::CXXRecordDecl*);
+ std::vector<BaseClass> GetUnambiguousPublicBases(
+ const clang::CXXRecordDecl& record_decl) const;
+};
+
+// A `DeclImporter` for `EnumDecl`s.
+class EnumDeclImporter : public DeclImporterBase<clang::EnumDecl> {
+ public:
+ EnumDeclImporter(ImportContext& context) : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::EnumDecl*);
+};
+
+// A `DeclImporter` for `FunctionTemplateDecl`s.
+class FunctionTemplateDeclImporter
+ : public DeclImporterBase<clang::FunctionTemplateDecl> {
+ public:
+ FunctionTemplateDeclImporter(ImportContext& context)
+ : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::FunctionTemplateDecl*);
+};
+
+// A `DeclImporter` for `FunctionDecl`s.
+class FunctionDeclImporter : public DeclImporterBase<clang::FunctionDecl> {
+ public:
+ FunctionDeclImporter(ImportContext& context) : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::FunctionDecl*);
+};
+
+// A `DeclImporter` for `NamespaceDecl`s.
+class NamespaceDeclImporter : public DeclImporterBase<clang::NamespaceDecl> {
+ public:
+ NamespaceDeclImporter(ImportContext& context) : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::NamespaceDecl*);
+};
+
+// A `DeclImporter` for `TypedefNameDecl`s.
+class TypedefNameDeclImporter
+ : public DeclImporterBase<clang::TypedefNameDecl> {
+ public:
+ TypedefNameDeclImporter(ImportContext& context) : DeclImporterBase(context){};
+ std::optional<IR::Item> Import(clang::TypedefNameDecl*);
+};
+
+// Iterates over the AST created from the invocation's entry headers and
+// creates an intermediate representation of the import (`IR`) into the
+// invocation object.
+class Importer : public ImportContext {
+ public:
+ explicit Importer(Invocation& invocation, clang::ASTContext& ctx,
+ clang::Sema& sema)
+ : ImportContext(invocation, ctx, sema),
+ mangler_(CRUBIT_DIE_IF_NULL(ctx_.createMangleContext())) {
+ decl_importers_.push_back(
+ std::make_unique<ClassTemplateDeclImporter>(*this));
+ decl_importers_.push_back(std::make_unique<CXXRecordDeclImporter>(*this));
+ decl_importers_.push_back(std::make_unique<EnumDeclImporter>(*this));
+ decl_importers_.push_back(std::make_unique<FunctionDeclImporter>(*this));
+ decl_importers_.push_back(
+ std::make_unique<FunctionTemplateDeclImporter>(*this));
+ decl_importers_.push_back(std::make_unique<NamespaceDeclImporter>(*this));
+ decl_importers_.push_back(std::make_unique<TypedefNameDeclImporter>(*this));
+ }
+
+ // Import all visible declarations from a translation unit.
+ void Import(clang::TranslationUnitDecl* decl);
+
+ protected:
+ // Implementation of `ImportContext`
+ void ImportDeclsFromDeclContext(
+ const clang::DeclContext* decl_context) override;
+ IR::Item ImportUnsupportedItem(const clang::Decl* decl,
+ std::string error) override;
+ IR::Item ImportUnsupportedItem(const clang::Decl* decl,
+ std::set<std::string> errors) override;
+ std::vector<ItemId> GetItemIdsInSourceOrder(clang::Decl* decl) override;
+ std::string GetMangledName(const clang::NamedDecl* named_decl) const override;
+ BazelLabel GetOwningTarget(const clang::Decl* decl) const override;
+ bool IsFromCurrentTarget(const clang::Decl* decl) const override;
+ std::optional<UnqualifiedIdentifier> GetTranslatedName(
+ const clang::NamedDecl* named_decl) const override;
std::optional<Identifier> GetTranslatedIdentifier(
- const clang::NamedDecl* named_decl) const {
+ const clang::NamedDecl* named_decl) const override {
if (std::optional<UnqualifiedIdentifier> name =
GetTranslatedName(named_decl)) {
return std::move(*std::get_if<Identifier>(&*name));
}
return std::nullopt;
}
+ llvm::Optional<std::string> GetComment(
+ const clang::Decl* decl) const override;
+ SourceLoc ConvertSourceLocation(clang::SourceLocation loc) const override;
- // Gets the doc comment of the declaration.
- llvm::Optional<std::string> GetComment(const clang::Decl* decl) const;
+ private:
+ // Returns the Item of a Decl, importing it first if necessary.
+ std::optional<IR::Item> GetDeclItem(clang::Decl* decl);
- SourceLoc ConvertSourceLocation(clang::SourceLocation loc) const;
+ // Imports a decl and creates an IR item (or error messages).
+ // Does not use or update the cache.
+ std::optional<IR::Item> ImportDecl(clang::Decl* decl);
- std::vector<BaseClass> GetUnambiguousPublicBases(
- const clang::CXXRecordDecl& record_decl) const;
+ // Stores the comments of this target in source order.
+ void ImportFreeComments();
- Invocation& invocation_;
-
- clang::ASTContext& ctx_;
- clang::Sema& sema_;
-
+ std::vector<std::unique_ptr<DeclImporter>> decl_importers_;
std::unique_ptr<clang::MangleContext> mangler_;
absl::flat_hash_map<const clang::Decl*, std::optional<IR::Item>>
import_cache_;
- TypeMapper type_mapper_;
std::vector<const clang::RawComment*> comments_;
}; // class Importer
