Support anonymous struct and union fields in interop

Fix #729

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt

@@ -27,10 +27,10 @@ private class StructDeclImpl(spelling: String) : StructDecl(spelling) {
 
 private class StructDefImpl(
         size: Long, align: Int, decl: StructDecl,
-        hasNaturalLayout: Boolean, hasUnalignedFields: Boolean
+        hasNaturalLayout: Boolean
 ) : StructDef(
         size, align, decl,
-        hasNaturalLayout = hasNaturalLayout, hasUnalignedFields = hasUnalignedFields
+        hasNaturalLayout = hasNaturalLayout
 ) {
 
     override val fields = mutableListOf<Field>()
@@ -140,20 +140,39 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
 
         val structDef = StructDefImpl(
                 size, align, structDecl,
-                hasNaturalLayout = structHasNaturalLayout(cursor),
-                hasUnalignedFields = structHasUnalignedFields(cursor)
+                hasNaturalLayout = structHasNaturalLayout(cursor)
         )
 
         structDecl.def = structDef
 
-        visitChildren(cursor) { childCursor: CValue<CXCursor>, _: CValue<CXCursor> ->
-            if (clang_getCursorKind(childCursor) == CXCursorKind.CXCursor_FieldDecl) {
-                val name = clang_getCursorSpelling(childCursor).convertAndDispose()
-                val fieldType = convertCursorType(childCursor)
-                val offset = clang_Cursor_getOffsetOfField(childCursor)
-                structDef.fields.add(Field(name, fieldType, offset))
+        addDeclaredFields(structDef, type, type)
+    }
+
+    private fun addDeclaredFields(structDef: StructDefImpl, structType: CValue<CXType>, containerType: CValue<CXType>) {
+        getFields(containerType).forEach { fieldCursor ->
+            val name = getCursorSpelling(fieldCursor)
+            if (name.isNotEmpty()) {
+                val fieldType = convertCursorType(fieldCursor)
+                val offset = clang_Type_getOffsetOf(structType, name)
+                if (clang_Cursor_isBitField(fieldCursor) == 0) {
+                    val typeAlign = clang_Type_getAlignOf(clang_getCursorType(fieldCursor))
+                    structDef.fields.add(Field(name, fieldType, offset, typeAlign))
+                } else {
+                    // Ignore bit fields for now.
+                }
+            } else {
+                // Unnamed field.
+                val fieldType = clang_getCursorType(fieldCursor)
+                when (fieldType.kind) {
+                    CXTypeKind.CXType_Record -> {
+                        // Unnamed struct fields also contribute their fields:
+                        addDeclaredFields(structDef, structType, fieldType)
+                    }
+                    else -> {
+                        // Nothing.
+                    }
+                }
             }
-            CXChildVisitResult.CXChildVisit_Continue
         }
     }
 
@@ -341,27 +360,6 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
         }
     }
 
-    /**
-     * Computes [StructDef.hasUnalignedFields] property.
-     */
-    fun structHasUnalignedFields(structDefCursor: CValue<CXCursor>): Boolean {
-        var hasUnalignedFields = false
-        visitChildren(structDefCursor) { child, _ ->
-            if (clang_getCursorKind(child) == CXCursorKind.CXCursor_FieldDecl &&
-                    clang_Cursor_isBitField(child) == 0 &&
-                    clang_Cursor_getOffsetOfField(child) %
-                            (clang_Type_getAlignOf(clang_getCursorType(child)) * 8) != 0L) {
-
-                hasUnalignedFields = true
-                CXChildVisitResult.CXChildVisit_Break
-            } else {
-                CXChildVisitResult.CXChildVisit_Continue
-            }
-        }
-
-        return hasUnalignedFields
-    }
-
     private fun convertCursorType(cursor: CValue<CXCursor>) =
         convertType(clang_getCursorType(cursor), clang_getDeclTypeAttributes(cursor))
 
@@ -507,7 +505,12 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
 
         when (kind) {
             CXIdxEntity_Struct, CXIdxEntity_Union -> {
-                getStructDeclAt(cursor)
+                if (entityName == null) {
+                    // Skip anonymous struct.
+                    // (It gets included anyway if used as a named field type).
+                } else {
+                    getStructDeclAt(cursor)
+                }
             }
 
             CXIdxEntity_Typedef -> {

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/NativeIndex.kt

@@ -50,7 +50,10 @@ abstract class NativeIndex {
 /**
  * C struct field.
  */
-class Field(val name: String, val type: Type, val offset: Long)
+class Field(val name: String, val type: Type, val offset: Long, val typeAlign: Long)
+
+val Field.isAligned: Boolean
+    get() = offset % (typeAlign * 8) == 0L
 
 /**
  * C struct declaration.
@@ -68,8 +71,7 @@ abstract class StructDecl(val spelling: String) {
  */
 abstract class StructDef(val size: Long, val align: Int,
                          val decl: StructDecl,
-                         val hasNaturalLayout: Boolean,
-                         val hasUnalignedFields: Boolean) {
+                         val hasNaturalLayout: Boolean) {
 
     abstract val fields: List<Field>
 }

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt

@@ -137,17 +137,41 @@ internal typealias CursorVisitor = (cursor: CValue<CXCursor>, parent: CValue<CXC
 
 internal fun visitChildren(parent: CValue<CXCursor>, visitor: CursorVisitor) {
     val visitorPtr = StableObjPtr.create(visitor)
-    val clientData = visitorPtr.value
-    clang_visitChildren(parent, staticCFunction { cursor, parent, clientData ->
-        @Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
-        val visitor = StableObjPtr.fromValue(clientData!!).get() as CursorVisitor
-        visitor(cursor, parent)
-    }, clientData)
+    try {
+        val clientData = visitorPtr.value
+        clang_visitChildren(parent, staticCFunction { cursor, parent, clientData ->
+            @Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
+            val visitor = StableObjPtr.fromValue(clientData!!).get() as CursorVisitor
+            visitor(cursor, parent)
+        }, clientData)
+    } finally {
+        visitorPtr.dispose()
+    }
 }
 
 internal fun visitChildren(translationUnit: CXTranslationUnit, visitor: CursorVisitor) =
         visitChildren(clang_getTranslationUnitCursor(translationUnit), visitor)
 
+internal fun getFields(type: CValue<CXType>): List<CValue<CXCursor>> {
+    val result = mutableListOf<CValue<CXCursor>>()
+    val resultPtr = StableObjPtr.create(result)
+    try {
+        val clientData = resultPtr.value
+
+        @Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
+        clang_Type_visitFields(type, staticCFunction { cursor, clientData ->
+            val result = StableObjPtr.fromValue(clientData!!).get() as MutableList<CValue<CXCursor>>
+            result.add(cursor)
+            CXVisitorResult.CXVisit_Continue
+        }, clientData)
+
+    } finally {
+        resultPtr.dispose()
+    }
+
+    return result
+}
+
 internal fun CValue<CXCursor>.isLeaf(): Boolean {
     var hasChildren = false
 

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/ObjCStubs.kt

@@ -213,8 +213,11 @@ private fun Type.isLargeOrUnaligned(): Boolean {
 private fun Type.hasUnalignedMembers(): Boolean = when (this) {
     is Typedef -> this.def.aliased.hasUnalignedMembers()
     is RecordType -> this.decl.def!!.let { def ->
-        def.hasUnalignedFields || // Check members of fields too:
-                def.fields.any { it.type.hasUnalignedMembers() }
+        def.fields.any {
+            !it.isAligned ||
+                    // Check members of fields too:
+                    it.type.hasUnalignedMembers()
+        }
     }
     is ArrayType -> this.elemType.hasUnalignedMembers()
     else -> false

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt

@@ -267,9 +267,9 @@ class StubGenerator(
             out("companion object : Type(${def.size}, ${def.align})") // FIXME: align
             out("")
             for (field in def.fields) {
-                if (field.name.isEmpty()) continue
-
                 try {
+                    assert(field.name.isNotEmpty())
+
                     if (field.offset < 0) throw NotImplementedError();
                     assert(field.offset % 8 == 0L)
                     val offset = field.offset / 8