[cxx-interop] Use typedef's swift_name attr to rename anonymous enums.

Author: zoecarver

lib/ClangImporter/ImportName.cpp

@@ -628,6 +628,22 @@ findSwiftNameAttr(const clang::Decl *decl, ImportNameVersion version) {
         activeAttr = decodeAttr(nameAttr);
     }
 
+    if (auto enumDecl = dyn_cast<clang::EnumDecl>(decl)) {
+      // Intentionally don't get the cannonical type here.
+      if (auto typedefType = dyn_cast<clang::TypedefType>(enumDecl->getIntegerType().getTypePtr())) {
+        // If the typedef is available in Swift, the user will get ambiguity.
+        // It also means they may not have intended this API to be imported like this.
+        if (importer::isUnavailableInSwift(typedefType->getDecl(), nullptr, true)) {
+          if (auto asyncAttr = typedefType->getDecl()->getAttr<clang::SwiftAsyncNameAttr>())
+            activeAttr = decodeAttr(asyncAttr);
+          if (!activeAttr) {
+            if (auto nameAttr = typedefType->getDecl()->getAttr<clang::SwiftNameAttr>())
+              activeAttr = decodeAttr(nameAttr);
+          }
+        }
+      }
+    }
+
     Optional<AnySwiftNameAttr> result = activeAttr;
     llvm::VersionTuple bestSoFar;
     for (auto *attr : decl->attrs()) {

test/Interop/Cxx/enum/Inputs/anonymous-with-swift-name.h

@@ -22,6 +22,22 @@ typedef CF_OPTIONS(unsigned, CFColorMask) {
 inline SOColorMask useSOColorMask(SOColorMask mask) { return mask; }
 inline CFColorMask useCFColorMask(CFColorMask mask) { return mask; }
 
+struct ParentStruct { };
+
+typedef __attribute__((availability(swift, unavailable))) __attribute__((swift_name("ParentStruct.NewName"))) unsigned OldName;
+
+enum __attribute__((flag_enum,enum_extensibility(open))) : OldName {
+  kOldNameOne = (1 << 1),
+  kOldNameTwo = (1 << 2)
+};
+
+typedef __attribute__((availability(swift, unavailable))) __attribute__((swift_name("GlobalNewName"))) unsigned GlobalOldName;
+
+enum __attribute__((flag_enum,enum_extensibility(open))) : GlobalOldName {
+  kGlobalOldNameOne = (1 << 1),
+  kGlobalOldNameTwo = (1 << 2)
+};
+
 #if __OBJC__
 @interface ColorMaker
 - (void)makeColorWithOptions:(SOColorMask)opts;

test/Interop/Cxx/enum/anonymous-with-swift-name-module-interface.swift

@@ -56,3 +56,50 @@
 
 // CHECK: func useSOColorMask(_ mask: SOColorMask) -> SOColorMask
 // CHECK: func useCFColorMask(_ mask: CFColorMask) -> CFColorMask
+
+// Test rename with "swift_name" attr:
+// CHECK: struct ParentStruct
+
+// CHECK: @available(swift, obsoleted: 3, renamed: "ParentStruct.NewName")
+// CHECK: @available(*, unavailable, message: "Not available in Swift")
+// CHECK: typealias OldName = ParentStruct.NewName
+// CHECK: extension ParentStruct {
+// CHECK:     @available(*, unavailable, message: "Not available in Swift")
+// CHECK:     typealias NewName = UInt32
+// CHECK:     struct NewName : OptionSet, @unchecked Sendable {
+// CHECK:         init(rawValue: UInt32)
+// CHECK:         let rawValue: UInt32
+// CHECK:         typealias RawValue = UInt32
+// CHECK:         typealias Element = ParentStruct.NewName
+// CHECK:         typealias ArrayLiteralElement = ParentStruct.NewName
+// CHECK:         static var one: ParentStruct.NewName { get }
+// CHECK:         @available(swift, obsoleted: 3, renamed: "one")
+// CHECK:         static var One: ParentStruct.NewName { get }
+// CHECK:         static var two: ParentStruct.NewName { get }
+// CHECK:         @available(swift, obsoleted: 3, renamed: "two")
+// CHECK:         static var Two: ParentStruct.NewName { get }
+// CHECK:     }
+// CHECK: }
+
+// CHECK: @available(swift, obsoleted: 3, renamed: "ParentStruct.NewName")
+// CHECK: typealias OldName = ParentStruct.NewName
+// CHECK: @available(*, unavailable, message: "Not available in Swift")
+// CHECK: typealias GlobalNewName = UInt32
+// CHECK: @available(swift, obsoleted: 3, renamed: "GlobalNewName")
+// CHECK: @available(*, unavailable, message: "Not available in Swift")
+// CHECK: typealias GlobalOldName = GlobalNewName
+// CHECK: struct GlobalNewName : OptionSet, @unchecked Sendable {
+// CHECK:     init(rawValue: UInt32)
+// CHECK:     let rawValue: UInt32
+// CHECK:     typealias RawValue = UInt32
+// CHECK:     typealias Element = GlobalNewName
+// CHECK:     typealias ArrayLiteralElement = GlobalNewName
+// CHECK:     static var one: GlobalNewName { get }
+// CHECK:     @available(swift, obsoleted: 3, renamed: "one")
+// CHECK:     static var One: GlobalNewName { get }
+// CHECK:     static var two: GlobalNewName { get }
+// CHECK:     @available(swift, obsoleted: 3, renamed: "two")
+// CHECK:     static var Two: GlobalNewName { get }
+// CHECK: }
+// CHECK: @available(swift, obsoleted: 3, renamed: "GlobalNewName")
+// CHECK: typealias GlobalOldName = GlobalNewName