[StubIr][Metadata] Add support for array members of structs

Interop/Runtime/src/native/kotlin/kotlinx/cinterop/internal/Annotations.kt

@@ -10,6 +10,10 @@ annotation class CStruct(val spelling: String) {
     )
     annotation class MemberAt(val offset: Long)
 
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.PROPERTY_GETTER)
+    annotation class ArrayMemberAt(val offset: Long)
+
     @Retention(AnnotationRetention.BINARY)
     @Target(
             AnnotationTarget.PROPERTY_GETTER,

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

@@ -202,6 +202,8 @@ sealed class AnnotationStub(val classifier: Classifier) {
     class CStruct(val struct: String) : AnnotationStub(cStructClassifier) {
         class MemberAt(val offset: Long) : AnnotationStub(cStructClassifier.nested("MemberAt"))
 
+        class ArrayMemberAt(val offset: Long) : AnnotationStub(cStructClassifier.nested("ArrayMemberAt"))
+
         class BitField(val offset: Long, val size: Int) : AnnotationStub(cStructClassifier.nested("BitField"))
 
         class VarType(val size: Long, val align: Int) : AnnotationStub(cStructClassifier.nested("VarType"))

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

@@ -86,7 +86,7 @@ internal class StructStubBuilder(
                     }
                     val getter = when (context.generationMode) {
                         GenerationMode.SOURCE_CODE -> PropertyAccessor.Getter.ArrayMemberAt(offset)
-                        GenerationMode.METADATA -> PropertyAccessor.Getter.ExternalGetter(listOf(AnnotationStub.CStruct.MemberAt(offset)))
+                        GenerationMode.METADATA -> PropertyAccessor.Getter.ExternalGetter(listOf(AnnotationStub.CStruct.ArrayMemberAt(offset)))
                     }
                     val kind = PropertyStub.Kind.Val(getter)
                     // TODO: Should receiver be added?

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

@@ -393,6 +393,9 @@ private class MappingExtensions(
             is AnnotationStub.CStruct.MemberAt -> mapOfNotNull(
                     ("offset" to KmAnnotationArgument.LongValue(offset))
             )
+            is AnnotationStub.CStruct.ArrayMemberAt -> mapOfNotNull(
+                    ("offset" to KmAnnotationArgument.LongValue(offset))
+            )
             is AnnotationStub.CStruct.BitField -> mapOfNotNull(
                     ("offset" to KmAnnotationArgument.LongValue(offset)),
                     ("size" to KmAnnotationArgument.IntValue(size))

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

@@ -499,6 +499,7 @@ class StubIrTextEmitter(
         is AnnotationStub.CEnumEntryAlias,
         is AnnotationStub.CEnumVarTypeSize,
         is AnnotationStub.CStruct.MemberAt,
+        is AnnotationStub.CStruct.ArrayMemberAt,
         is AnnotationStub.CStruct.BitField,
         is AnnotationStub.CStruct.VarType ->
             error("${annotationStub.classifier.fqName} annotation is unsupported in textual mode")

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

@@ -185,6 +185,11 @@ private object PredefinedTypesHandler {
         return AbbreviatedType(objCClass, KotlinTypes.objCObjectMeta, emptyList(), nullable)
     }
 
+    private fun expandCArrayPointer(typeArguments: List<TypeArgument>, nullable: Boolean): AbbreviatedType {
+        val cPointer = ClassifierStubType(KotlinTypes.cPointer, typeArguments)
+        return AbbreviatedType(cPointer, KotlinTypes.cArrayPointer, typeArguments, nullable)
+    }
+
     /**
      * @return [ClassifierStubType] if [classifier] is a typealias from [kotlinx.cinterop] package.
      */
@@ -195,6 +200,7 @@ private object PredefinedTypesHandler {
                 KotlinTypes.cOpaquePointerVar.classifier -> expandCOpaquePointerVar(nullable)
                 KotlinTypes.cPointerVar -> expandCPointerVar(typeArguments, nullable)
                 KotlinTypes.objCObjectMeta -> expandObjCObjectMeta(typeArguments, nullable)
+                KotlinTypes.cArrayPointer -> expandCArrayPointer(typeArguments, nullable)
                 else -> null
             }
 

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/RuntimeNames.kt

@@ -11,6 +11,7 @@ object RuntimeNames {
     val exportTypeInfoAnnotation = FqName("kotlin.native.internal.ExportTypeInfo")
     val cCall = FqName("kotlinx.cinterop.internal.CCall")
     val cStructMemberAt = FqName("kotlinx.cinterop.internal.CStruct.MemberAt")
+    val cStructArrayMemberAt = FqName("kotlinx.cinterop.internal.CStruct.ArrayMemberAt")
     val cStructBitField = FqName("kotlinx.cinterop.internal.CStruct.BitField")
     val objCMethodAnnotation = FqName("kotlinx.cinterop.ObjCMethod")
     val objCMethodImp = FqName("kotlinx.cinterop.ObjCMethodImp")

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropCallConvertors.kt

@@ -39,6 +39,9 @@ private fun isEnumVarValueAccessor(function: IrFunction, symbols: KonanSymbols):
 private fun isMemberAtAccessor(function: IrFunction): Boolean =
         function.hasAnnotation(RuntimeNames.cStructMemberAt)
 
+private fun isArrayMemberAtAccessor(function: IrFunction): Boolean =
+        function.hasAnnotation(RuntimeNames.cStructArrayMemberAt)
+
 private fun isBitFieldAccessor(function: IrFunction): Boolean =
         function.hasAnnotation(RuntimeNames.cStructBitField)
 
@@ -238,6 +241,8 @@ internal fun tryGenerateInteropMemberAccess(
         generateInteropCall(symbols, builder) { generateMemberAtAccess(callSite) }
     isBitFieldAccessor(callSite.symbol.owner) ->
         generateInteropCall(symbols, builder) { generateBitFieldAccess(callSite) }
+    isArrayMemberAtAccessor(callSite.symbol.owner) ->
+        generateInteropCall(symbols, builder) { generateArrayMemberAtAccess(callSite) }
     else -> null
 }
 
@@ -283,6 +288,16 @@ private fun InteropCallContext.generateMemberAtAccess(callSite: IrCall): IrExpre
     }
 }
 
+private fun InteropCallContext.generateArrayMemberAtAccess(callSite: IrCall): IrExpression {
+    val accessor = callSite.symbol.owner
+    val memberAt = accessor.getAnnotation(RuntimeNames.cStructArrayMemberAt)!!
+    val offset = (memberAt.getValueArgument(0) as IrConst<Long>).value
+    val fieldPointer = calculateFieldPointer(callSite.dispatchReceiver!!, offset)
+    return builder.irCall(symbols.interopInterpretCPointer).also {
+        it.putValueArgument(0, fieldPointer)
+    }
+}
+
 private fun InteropCallContext.writeBits(
         base: IrExpression,
         offset: Long,