Merge pull request #37287 from plotfi/cxx-interop-anon-union

Author: swift-ci

lib/ClangImporter/ImportDecl.cpp

@@ -3516,6 +3516,20 @@ namespace {
             Impl.ImportedDecls.end())
           continue;
 
+        // If we encounter an IndirectFieldDecl, ensure that its parent is
+        // importable before attempting to import it because they are dependent
+        // when it comes to getter/setter generation.
+        if (const auto *ind = dyn_cast<clang::IndirectFieldDecl>(nd)) {
+          const clang::CXXRecordDecl *parentUnion =
+              (ind->getChainingSize() >= 2)
+                  ? dyn_cast<clang::CXXRecordDecl>(
+                        ind->getAnonField()->getParent())
+                  : nullptr;
+          if (parentUnion && parentUnion->isAnonymousStructOrUnion() &&
+              parentUnion->isUnion() && !isCxxRecordImportable(parentUnion))
+            continue;
+        }
+
         auto member = Impl.importDecl(nd, getActiveSwiftVersion());
         if (!member) {
           if (!isa<clang::TypeDecl>(nd) && !isa<clang::FunctionDecl>(nd)) {

test/Interop/Cxx/union/Inputs/anonymous-union-partly-invalid.h

@@ -0,0 +1,16 @@
+@class C;
+@interface C
+{}
+@end
+
+struct S {
+  union {
+    C *t;
+    char c;
+  };
+  S(const S &s) {}
+  ~S() { }
+  int f() { return 42; }
+};
+
+S *getSPtr();

test/Interop/Cxx/union/Inputs/module.modulemap

@@ -0,0 +1,4 @@
+module AnonymousUnionPartlyInvalid {
+  header "anonymous-union-partly-invalid.h"
+  requires cplusplus
+}

test/Interop/Cxx/union/anonymous-union-partly-invalid-module-interface.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=AnonymousUnionPartlyInvalid -I %S/Inputs -source-filename=x -enable-cxx-interop -enable-objc-interop | %FileCheck %s
+
+// CHECK: class C {
+// CHECK-NEXT: }
+// CHECK-NEXT: struct S {
+// CHECK-NEXT:   mutating func f() -> Int32
+// CHECK-NEXT: }
+// CHECK-NEXT: func getSPtr() -> UnsafeMutablePointer<S>!

test/Interop/Cxx/union/anonymous-union-partly-invalid.swift

@@ -0,0 +1,13 @@
+// RUN: %swift -I %S/Inputs -enable-cxx-interop -enable-objc-interop -emit-ir %s | %FileCheck %s
+
+import AnonymousUnionPartlyInvalid
+
+let sPtr = getSPtr()
+let a = sPtr![0].f()
+
+// CHECK: i32 @main
+// CHECK-NEXT: entry:
+// CHECK-NEXT: bitcast
+// CHECK-NEXT: call %struct.S
+// CHECK-NEXT: ptrtoint %struct.S
+