Merge pull request swiftlang#80598 from swiftlang/gaborh/nested-foreign-type-metadata

[cxx-interop] Fix a rare compilation error in reverse interop header

Author: Xazax-hun

include/swift/ClangImporter/ClangImporter.h

@@ -773,6 +773,9 @@ getPrivateFileIDAttrs(const clang::CXXRecordDecl *decl);
 ///
 /// Returns false if \a decl was not imported by ClangImporter.
 bool declIsCxxOnly(const Decl *decl);
+
+/// Is this DeclContext an `enum` that represents a C++ namespace?
+bool isClangNamespace(const DeclContext *dc);
 } // namespace importer
 
 struct ClangInvocationFileMapping {

lib/ClangImporter/ClangImporter.cpp

@@ -8793,3 +8793,10 @@ bool importer::declIsCxxOnly(const Decl *decl) {
   }
   return false;
 }
+
+bool importer::isClangNamespace(const DeclContext *dc) {
+  if (const auto *ed = dc->getSelfEnumDecl())
+    return isa_and_nonnull<clang::NamespaceDecl>(ed->getClangDecl());
+
+  return false;
+}

lib/ClangImporter/ImportDecl.cpp

@@ -76,6 +76,7 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/Path.h"
 
 #include <algorithm>
@@ -3745,13 +3746,6 @@ namespace {
       return nullptr;
     }
 
-    static bool isClangNamespace(const DeclContext *dc) {
-      if (const auto *ed = dc->getSelfEnumDecl())
-        return isa<clang::NamespaceDecl>(ed->getClangDecl());
-
-      return false;
-    }
-
     Decl *importFunctionDecl(
         const clang::FunctionDecl *decl, ImportedName importedName,
         std::optional<ImportedName> correctSwiftName,

lib/PrintAsClang/ClangSyntaxPrinter.cpp

@@ -207,7 +207,8 @@ void ClangSyntaxPrinter::printNamespace(
 void ClangSyntaxPrinter::printParentNamespaceForNestedTypes(
     const ValueDecl *D, llvm::function_ref<void(raw_ostream &OS)> bodyPrinter,
     NamespaceTrivia trivia) const {
-  if (!isa_and_nonnull<NominalTypeDecl>(D->getDeclContext()->getAsDecl())) {
+  if (!isa_and_nonnull<NominalTypeDecl>(D->getDeclContext()->getAsDecl()) ||
+      importer::isClangNamespace(D->getDeclContext())) {
     bodyPrinter(os);
     return;
   }

lib/PrintAsClang/PrintClangValueType.cpp

@@ -630,18 +630,21 @@ void ClangValueTypePrinter::printTypeGenericTraits(
     bool isOpaqueLayout) {
   auto *NTD = dyn_cast<NominalTypeDecl>(typeDecl);
   ClangSyntaxPrinter printer(typeDecl->getASTContext(), os);
-  // FIXME: avoid popping out of the module's namespace here.
-  os << "} // end namespace \n\n";
-  os << "namespace swift SWIFT_PRIVATE_ATTR {\n";
-
   if (typeDecl->hasClangNode()) {
     /// Print a reference to the type metadata function for a C++ type.
-    ClangSyntaxPrinter(typeDecl->getASTContext(), os).printNamespace(
-        cxx_synthesis::getCxxImplNamespaceName(), [&](raw_ostream &os) {
-          ClangSyntaxPrinter(typeDecl->getASTContext(), os).printCTypeMetadataTypeFunction(
-              typeDecl, typeMetadataFuncName, typeMetadataFuncRequirements);
-        });
+    printer.printParentNamespaceForNestedTypes(typeDecl, [&](raw_ostream &os) {
+      printer.printNamespace(
+          cxx_synthesis::getCxxImplNamespaceName(), [&](raw_ostream &os) {
+            ClangSyntaxPrinter(typeDecl->getASTContext(), os)
+                .printCTypeMetadataTypeFunction(typeDecl, typeMetadataFuncName,
+                                                typeMetadataFuncRequirements);
+          });
+    });
   }
+
+  // FIXME: avoid popping out of the module's namespace here.
+  os << "} // end namespace \n\n";
+  os << "namespace swift SWIFT_PRIVATE_ATTR {\n";
   auto classDecl = dyn_cast<ClassDecl>(typeDecl);
   bool addPointer =
       typeDecl->isObjC() || (classDecl && classDecl->isForeignReferenceType());
@@ -676,10 +679,11 @@ void ClangValueTypePrinter::printTypeGenericTraits(
   ClangSyntaxPrinter(typeDecl->getASTContext(), os).printInlineForHelperFunction();
   os << "void * _Nonnull getTypeMetadata() {\n";
   os << "    return ";
-  if (!typeDecl->hasClangNode()) {
+  if (typeDecl->hasClangNode())
+    printer.printBaseName(moduleContext);
+  else
     printer.printBaseName(typeDecl->getModuleContext());
-    os << "::";
-  }
+  os << "::";
   if (!printer.printNestedTypeNamespaceQualifiers(typeDecl))
     os << "::";
   os << cxx_synthesis::getCxxImplNamespaceName() << "::";

test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift

@@ -200,10 +200,7 @@ public struct Strct {
 // CHECK:  ns::ImmortalTemplate<int> *_Nonnull retImmortalTemplate() noexcept SWIFT_SYMBOL({{.*}}) SWIFT_WARN_UNUSED_RESULT {
 // CHECK-NEXT: return UseCxxTy::_impl::$s8UseCxxTy19retImmortalTemplateSo2nsO0028ImmortalTemplateCInt_jBAGgnbVyF();
 // CHECK-NEXT: }
-
-// CHECK: } // end namespace
 // CHECK-EMPTY:
-// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: namespace _impl {
 // CHECK-EMPTY:
 // CHECK-NEXT: // Type metadata accessor for NonTrivialTemplateInt
@@ -212,14 +209,17 @@ public struct Strct {
 // CHECK-EMPTY:
 // CHECK-NEXT: } // namespace _impl
 // CHECK-EMPTY:
+// CHECK-NEXT: } // end namespace
+// CHECK-EMPTY:
+// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: #pragma clang diagnostic push
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Wc++17-extensions"
 // CHECK-NEXT: template<>
 // CHECK-NEXT: inline const constexpr bool isUsableInGenericContext<ns::NonTrivialTemplateInt> = true;
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct TypeMetadataTrait<ns::NonTrivialTemplateInt> {
 // CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
-// CHECK-NEXT:     return _impl::$sSo2nsO0030NonTrivialTemplateCInt_hHAFhrbVMa(0)._0;
+// CHECK-NEXT:     return UseCxxTy::_impl::$sSo2nsO0030NonTrivialTemplateCInt_hHAFhrbVMa(0)._0;
 // CHECK-NEXT:   }
 // CHECK-NEXT: };
 // CHECK-NEXT: namespace _impl{
@@ -240,9 +240,6 @@ public struct Strct {
 // CHECK-NEXT: return result;
 // CHECK-NEXT: }
 // CHECK-EMPTY:
-// CHECK-NEXT: } // end namespace
-// CHECK-EMPTY:
-// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: namespace _impl {
 // CHECK-EMPTY:
 // CHECK-NEXT: // Type metadata accessor for NonTrivialTemplateTrivial
@@ -251,14 +248,17 @@ public struct Strct {
 // CHECK-EMPTY:
 // CHECK-NEXT: } // namespace _impl
 // CHECK-EMPTY:
+// CHECK-NEXT: } // end namespace
+// CHECK-EMPTY:
+// CHECK-NEXT: namespace swift SWIFT_PRIVATE_ATTR {
 // CHECK-NEXT: #pragma clang diagnostic push
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Wc++17-extensions"
 // CHECK-NEXT: template<>
 // CHECK-NEXT: inline const constexpr bool isUsableInGenericContext<ns::NonTrivialTemplateTrivial> = true;
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct TypeMetadataTrait<ns::NonTrivialTemplateTrivial> {
 // CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
-// CHECK-NEXT:     return _impl::$sSo2nsO0042NonTrivialTemplatensTrivialinNS_HlGFlenawcVMa(0)._0;
+// CHECK-NEXT:     return UseCxxTy::_impl::$sSo2nsO0042NonTrivialTemplatensTrivialinNS_HlGFlenawcVMa(0)._0;
 // CHECK-NEXT:   }
 // CHECK-NEXT: };
 // CHECK-NEXT: namespace _impl{

test/Interop/CxxToSwiftToCxx/nested-cxx-class-back-to-swift.swift

@@ -0,0 +1,27 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend %t/use-cxx-types.swift -module-name UseCxxTy -typecheck -verify -emit-clang-header-path %t/UseCxxTy.h -I %t -enable-experimental-cxx-interop -clang-header-expose-decls=all-public -disable-availability-checking
+// RUN: cat %t/header.h >> %t/full-header.h
+// RUN: cat %t/UseCxxTy.h >> %t/full-header.h
+// RUN: %target-interop-build-clangxx -std=c++20 -c -xc++-header %t/full-header.h -o %t/o.o
+
+//--- header.h
+
+struct Cell { class Visitor {}; };
+
+//--- module.modulemap
+module CxxTest {
+    header "header.h"
+    requires cplusplus
+}
+
+//--- use-cxx-types.swift
+import CxxTest
+
+public extension Cell.Visitor {
+    func visit() {}
+}
+
+public func f() -> [Cell.Visitor] {
+}

test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx.swift

@@ -94,7 +94,7 @@ public func retObjCClassArray() -> [ObjCKlass] {
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct TypeMetadataTrait<ObjCKlass*> {
 // CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
-// CHECK-NEXT:     return _impl::$sSo9ObjCKlassCMa(0)._0;
+// CHECK-NEXT:     return UseObjCTy::_impl::$sSo9ObjCKlassCMa(0)._0;
 // CHECK-NEXT:   }
 // CHECK-NEXT: };
 

test/Interop/SwiftToCxx/structs/nested-structs-in-cxx.swift

@@ -68,3 +68,11 @@ public class TestObject {
         case invalid
     }
 }
+
+extension RecordConfig.File {
+    public func getFileExtension() -> String { ".wav" }
+}
+
+public func getFiles() -> [RecordConfig.File] {
+    []
+}