Inherit @objc, dynamic, @implementation in @abi

ABI-only declarations now query their API counterpart for things like `isObjC()`, their ObjC name, dynamic status, etc. This means that `@objc` and friends can simply be omitted from an `@abi` attribute.

No tests in this commit since attribute checking hasn’t landed yet.

Author: beccadax

lib/AST/Decl.cpp

@@ -4058,6 +4058,10 @@ void ValueDecl::setIsObjC(bool value) {
 }
 
 Identifier ExtensionDecl::getObjCCategoryName() const {
+  auto abiRole = ABIRoleInfo(this);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getObjCCategoryName();
+
   // If there's an @objc attribute, it's authoritative. (ClangImporter
   // attaches one automatically.)
   if (auto objcAttr = getAttrs().getAttribute<ObjCAttr>(/*AllowInvalid*/true)) {
@@ -4293,6 +4297,10 @@ StringRef ValueDecl::getCDeclName() const {
       return clangDecl->getName();
   }
 
+  auto abiRole = ABIRoleInfo(this);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getCDeclName();
+
   // Handle explicit cdecl attributes.
   if (auto cdeclAttr = getAttrs().getAttribute<CDeclAttr>()) {
     return cdeclAttr->Name;
@@ -4331,6 +4339,10 @@ ValueDecl::getObjCRuntimeName(bool skipIsObjCResolution) const {
 
 std::optional<ObjCSelector>
 Decl::getExplicitObjCName(bool allowInvalid) const {
+  auto abiRole = ABIRoleInfo(this);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getExplicitObjCName();
+
   auto objcAttr = getAttrs().getAttribute<ObjCAttr>(allowInvalid);
   if (objcAttr && !objcAttr->isNameImplicit())
     return objcAttr->getName();
@@ -5025,6 +5037,10 @@ static bool checkAccessUsingAccessScopes(const DeclContext *useDC,
 static bool
 isObjCMemberImplementation(const ValueDecl *VD,
                            llvm::function_ref<AccessLevel()> getAccessLevel) {
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return isObjCMemberImplementation(abiRole.getCounterpart(), getAccessLevel);
+
   if (auto ED = dyn_cast<ExtensionDecl>(VD->getDeclContext()))
     if (ED->isObjCImplementation() && !isa<TypeDecl>(VD)) {
       auto attrDecl = isa<AccessorDecl>(VD)
@@ -6504,6 +6520,10 @@ static StringRef mangleObjCRuntimeName(const NominalTypeDecl *nominal,
 
 StringRef ClassDecl::getObjCRuntimeName(
                        llvm::SmallVectorImpl<char> &buffer) const {
+   auto abiRole = ABIRoleInfo(this);
+   if (!abiRole.providesAPI() && abiRole.getCounterpart())
+     return abiRole.getCounterpart()->getObjCRuntimeName(buffer);
+
   // If there is a Clang declaration, use it's runtime name.
   if (auto objcClass
         = dyn_cast_or_null<clang::ObjCInterfaceDecl>(getClangDecl()))
@@ -7012,6 +7032,10 @@ ProtocolDecl::getPrimaryAssociatedTypes() const {
 
 StringRef ProtocolDecl::getObjCRuntimeName(
                           llvm::SmallVectorImpl<char> &buffer) const {
+   auto abiRole = ABIRoleInfo(this);
+   if (!abiRole.providesAPI() && abiRole.getCounterpart())
+     return abiRole.getCounterpart()->getObjCRuntimeName(buffer);
+
   // If there is an 'objc' attribute with a name, use that name.
   if (auto objc = getAttrs().getAttribute<ObjCAttr>()) {
     if (auto name = objc->getName())
@@ -7484,6 +7508,10 @@ getNameFromObjcAttribute(const ObjCAttr *attr, DeclName preferredName) {
 
 ObjCSelector
 AbstractStorageDecl::getObjCGetterSelector(Identifier preferredName) const {
+   auto abiRole = ABIRoleInfo(this);
+   if (!abiRole.providesAPI() && abiRole.getCounterpart())
+     return abiRole.getCounterpart()->getObjCGetterSelector(preferredName);
+
   // If the getter has an @objc attribute with a name, use that.
   if (auto getter = getAccessor(AccessorKind::Get)) {
       if (auto name = getNameFromObjcAttribute(getter->getAttrs().
@@ -7514,6 +7542,10 @@ AbstractStorageDecl::getObjCGetterSelector(Identifier preferredName) const {
 
 ObjCSelector
 AbstractStorageDecl::getObjCSetterSelector(Identifier preferredName) const {
+   auto abiRole = ABIRoleInfo(this);
+   if (!abiRole.providesAPI() && abiRole.getCounterpart())
+     return abiRole.getCounterpart()->getObjCSetterSelector(preferredName);
+
   // If the setter has an @objc attribute with a name, use that.
   auto setter = getAccessor(AccessorKind::Set);
   auto objcAttr = setter ? setter->getAttrs().getAttribute<ObjCAttr>()
@@ -8501,6 +8533,10 @@ Type VarDecl::getPropertyWrapperInitValueInterfaceType() const {
 }
 
 Identifier VarDecl::getObjCPropertyName() const {
+   auto abiRole = ABIRoleInfo(this);
+   if (!abiRole.providesAPI() && abiRole.getCounterpart())
+     return abiRole.getCounterpart()->getObjCPropertyName();
+
   if (auto attr = getAttrs().getAttribute<ObjCAttr>()) {
     if (auto name = attr->getName())
       return name->getSelectorPieces()[0];
@@ -10119,6 +10155,11 @@ AbstractFunctionDecl::getBodyFingerprintIncludingLocalTypeMembers() const {
 ObjCSelector
 AbstractFunctionDecl::getObjCSelector(DeclName preferredName,
                                       bool skipIsObjCResolution) const {
+   auto abiRole = ABIRoleInfo(this);
+   if (!abiRole.providesAPI() && abiRole.getCounterpart())
+     return abiRole.getCounterpart()->getObjCSelector(preferredName,
+                                                      skipIsObjCResolution);
+
   // FIXME: Forces computation of the Objective-C selector.
   if (!skipIsObjCResolution)
     (void)isObjC();
@@ -11506,7 +11547,12 @@ bool ClassDecl::isNonDefaultExplicitDistributedActor(ModuleDecl *M,
 bool ClassDecl::isNativeNSObjectSubclass() const {
   // @objc actors implicitly inherit from NSObject.
   if (isActor()) {
-    if (getAttrs().hasAttribute<ObjCAttr>()) {
+    DeclAttributes attrs = getAttrs();
+    auto abiRole = ABIRoleInfo(this);
+    if (!abiRole.providesAPI() && abiRole.getCounterpart())
+      attrs = abiRole.getCounterpart()->getAttrs();
+
+    if (attrs.hasAttribute<ObjCAttr>()) {
       return true;
     }
     ClassDecl *superclass = getSuperclassDecl();

lib/AST/SwiftNameTranslation.cpp

@@ -37,6 +37,10 @@ getNameForObjC(const ValueDecl *VD, CustomNamesOnly_t customNamesOnly) {
   assert(isa<ClassDecl>(VD) || isa<ProtocolDecl>(VD) || isa<StructDecl>(VD) ||
          isa<EnumDecl>(VD) || isa<EnumElementDecl>(VD) ||
          isa<TypeAliasDecl>(VD));
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return getNameForObjC(abiRole.getCounterpart(), customNamesOnly);
+
   if (auto objc = VD->getAttrs().getAttribute<ObjCAttr>()) {
     if (auto name = objc->getName()) {
       assert(name->getNumSelectorPieces() == 1);
@@ -63,6 +67,10 @@ getErrorDomainStringForObjC(const EnumDecl *ED) {
   // Should have already been diagnosed as diag::objc_enum_generic.
   assert(!ED->isGenericContext() && "Trying to bridge generic enum error to Obj-C");
 
+  auto abiRole = ABIRoleInfo(ED);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return getErrorDomainStringForObjC(abiRole.getCounterpart());
+
   SmallVector<const NominalTypeDecl *, 4> outerTypes;
   for (const NominalTypeDecl * D = ED;
        D != nullptr;
@@ -86,6 +94,11 @@ getErrorDomainStringForObjC(const EnumDecl *ED) {
 bool swift::objc_translation::
 printSwiftEnumElemNameInObjC(const EnumElementDecl *EL, llvm::raw_ostream &OS,
                              Identifier PreferredName) {
+  auto abiRole = ABIRoleInfo(EL);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return printSwiftEnumElemNameInObjC(abiRole.getCounterpart(), OS,
+                                        PreferredName);
+
   StringRef ElemName = getNameForObjC(EL, CustomNamesOnly);
   if (!ElemName.empty()) {
     OS << ElemName;
@@ -104,6 +117,10 @@ printSwiftEnumElemNameInObjC(const EnumElementDecl *EL, llvm::raw_ostream &OS,
 
 std::pair<Identifier, ObjCSelector> swift::objc_translation::
 getObjCNameForSwiftDecl(const ValueDecl *VD, DeclName PreferredName){
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return getObjCNameForSwiftDecl(abiRole.getCounterpart(), PreferredName);
+
   ASTContext &Ctx = VD->getASTContext();
   Identifier BaseName;
   if (PreferredName) {
@@ -157,6 +174,10 @@ isVisibleToObjC(const ValueDecl *VD, AccessLevel minRequiredAccess,
 StringRef
 swift::cxx_translation::getNameForCxx(const ValueDecl *VD,
                                       CustomNamesOnly_t customNamesOnly) {
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return getNameForCxx(abiRole.getCounterpart(), customNamesOnly);
+
   ASTContext& ctx = VD->getASTContext();
 
   for (auto *EA : VD->getAttrs().getAttributes<ExposeAttr>()) {
@@ -214,6 +235,10 @@ swift::cxx_translation::DeclRepresentation
 swift::cxx_translation::getDeclRepresentation(
     const ValueDecl *VD,
     std::optional<std::function<bool(const NominalTypeDecl *)>> isZeroSized) {
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return getDeclRepresentation(abiRole.getCounterpart(), isZeroSized);
+
   if (getActorIsolation(const_cast<ValueDecl *>(VD)).isActorIsolated())
     return {Unsupported, UnrepresentableIsolatedInActor};
   if (isa<MacroDecl>(VD))

lib/AST/TypeCheckRequests.cpp

@@ -356,7 +356,8 @@ void IsDynamicRequest::cacheResult(bool value) const {
   decl->setIsDynamic(value);
 
   // Add an attribute for printing
-  if (value && !decl->getAttrs().hasAttribute<DynamicAttr>())
+  if (value && !decl->getAttrs().hasAttribute<DynamicAttr>() &&
+        ABIRoleInfo(decl).providesAPI())
     decl->getAttrs().add(new (decl->getASTContext()) DynamicAttr(/*Implicit=*/true));
 }
 

lib/ClangImporter/ClangImporter.cpp

@@ -6518,6 +6518,9 @@ findFunctionInterfaceAndImplementation(AbstractFunctionDecl *func) {
 
 ObjCInterfaceAndImplementation ObjCInterfaceAndImplementationRequest::
 evaluate(Evaluator &evaluator, Decl *decl) const {
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "@interface request for ABI-only decl?");
+
   // Types and extensions have direct links to their counterparts through the
   // `@_objcImplementation` attribute. Let's resolve that.
   // (Also directing nulls here, where they'll early-return.)
@@ -6557,6 +6560,21 @@ llvm::TinyPtrVector<Decl *> Decl::getAllImplementedObjCDecls() const {
     // This *is* the interface, if there is one.
     return {};
 
+  // ABI-only attributes don't have an `@implementation`, so query the API
+  // counterpart and map the results back to ABI decls.
+  auto abiRole = ABIRoleInfo(this);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart()) {
+    auto interfaceDecls =
+        abiRole.getCounterpart()->getAllImplementedObjCDecls();
+
+    // Map the APIs back to their ABI counterparts (often a no-op)
+    for (auto &interfaceDecl : interfaceDecls) {
+      interfaceDecl = ABIRoleInfo(interfaceDecl).getCounterpart();
+    }
+
+    return interfaceDecls;
+  }
+
   ObjCInterfaceAndImplementationRequest req{const_cast<Decl *>(this)};
   auto result = evaluateOrDefault(getASTContext().evaluator, req, {});
   return result.interfaceDecls;
@@ -6574,6 +6592,14 @@ Decl *Decl::getObjCImplementationDecl() const {
     // This *is* the implementation, if it has one.
     return nullptr;
 
+  // ABI-only attributes don't have an `@implementation`, so query the API
+  // counterpart and map the results back to ABI decls.
+  auto abiRole = ABIRoleInfo(this);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart()) {
+    auto implDecl = abiRole.getCounterpart()->getObjCImplementationDecl();
+    return ABIRoleInfo(implDecl).getCounterpart();
+  }
+
   ObjCInterfaceAndImplementationRequest req{const_cast<Decl *>(this)};
   auto result = evaluateOrDefault(getASTContext().evaluator, req, {});
   return result.implementationDecl;

lib/Sema/TypeCheckAttr.cpp

@@ -1707,6 +1707,10 @@ static SourceRange getArgListRange(ASTContext &Ctx, DeclAttribute *attr) {
 
 void AttributeChecker::
 visitObjCImplementationAttr(ObjCImplementationAttr *attr) {
+  // If `D` is ABI-only, let ABIDeclChecker diagnose the bad attribute.
+  if (!ABIRoleInfo(D).providesAPI())
+    return;
+
   DeclAttribute * langAttr =
     D->getAttrs().getAttribute<ObjCAttr>(/*AllowInvalid=*/true);
   if (!langAttr)

lib/Sema/TypeCheckDecl.cpp

@@ -938,6 +938,11 @@ IsStaticRequest::evaluate(Evaluator &evaluator, FuncDecl *decl) const {
 
 bool
 IsDynamicRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
+  // ABI-only decls get this from their API decl.
+  auto abiRole = ABIRoleInfo(decl);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->isDynamic();
+
   // If we can't infer dynamic here, don't.
   if (!DeclAttribute::canAttributeAppearOnDecl(DeclAttrKind::Dynamic, decl))
     return false;

lib/Sema/TypeCheckDeclObjC.cpp

@@ -650,6 +650,11 @@ bool swift::isRepresentableInObjC(
     const AbstractFunctionDecl *AFD, ObjCReason Reason,
     std::optional<ForeignAsyncConvention> &asyncConvention,
     std::optional<ForeignErrorConvention> &errorConvention) {
+  auto abiRole = ABIRoleInfo(AFD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return isRepresentableInObjC(abiRole.getCounterpart(), Reason,
+                                 asyncConvention, errorConvention);
+
   // Clear out the async and error conventions. They will be added later if
   // needed.
   asyncConvention = std::nullopt;
@@ -1104,6 +1109,10 @@ bool swift::isRepresentableInObjC(const VarDecl *VD, ObjCReason Reason) {
   if (VD->isInvalid())
     return false;
 
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return isRepresentableInObjC(abiRole.getCounterpart(), Reason);
+
   Type T = VD->getDeclContext()->mapTypeIntoContext(VD->getInterfaceType());
   if (auto *RST = T->getAs<ReferenceStorageType>()) {
     // In-memory layout of @weak and @unowned does not correspond to anything
@@ -1160,6 +1169,10 @@ bool swift::isRepresentableInObjC(const VarDecl *VD, ObjCReason Reason) {
 
 bool swift::isRepresentableInObjC(const SubscriptDecl *SD, ObjCReason Reason) {
   // If you change this function, you must add or modify a test in PrintAsClang.
+  auto abiRole = ABIRoleInfo(SD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return isRepresentableInObjC(abiRole.getCounterpart(), Reason);
+
   ASTContext &ctx = SD->getASTContext();
   DiagnosticStateRAII diagState(ctx.Diags);
   auto behavior = behaviorLimitForObjCReason(Reason, ctx);
@@ -1770,6 +1783,11 @@ static void markAsObjC(ValueDecl *D, ObjCReason reason,
 bool IsObjCRequest::evaluate(Evaluator &evaluator, ValueDecl *VD) const {
   DiagnosticStateRAII diagState(VD->getASTContext().Diags);
 
+  // ABI-only decls inherit objc-ness from their API.
+  auto abiRole = ABIRoleInfo(VD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->isObjC();
+
   // Access notes may add attributes that affect this calculus.
   TypeChecker::applyAccessNote(VD);
 
@@ -4113,6 +4131,9 @@ class ObjCImplementationChecker {
 
 evaluator::SideEffect TypeCheckObjCImplementationRequest::
 evaluate(Evaluator &evaluator, Decl *D) const {
+  if (!ABIRoleInfo(D).providesAPI())
+    return evaluator::SideEffect();
+
   PrettyStackTraceDecl trace("checking member implementations of", D);
 
   // FIXME: Because we check extension-by-extension, candidates and requirements