backend: handle initializers in interop lowering

Also add lowering utils.

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/common/lower/LowerUtils.kt

@@ -4,13 +4,14 @@ import org.jetbrains.kotlin.backend.common.BackendContext
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
-import org.jetbrains.kotlin.ir.declarations.IrClass
-import org.jetbrains.kotlin.ir.declarations.IrConstructor
+import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.IrDelegatingConstructorCall
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
+import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.name.Name
@@ -54,6 +55,42 @@ inline fun IrGeneratorWithScope.irBlock(expression: IrExpression, origin: IrStat
 inline fun IrGeneratorWithScope.irBlockBody(irElement: IrElement, body: IrBlockBodyBuilder.() -> Unit) =
         this.irBlockBody(irElement.startOffset, irElement.endOffset, body)
 
+open class IrBuildingTransformer(private val context: BackendContext) : IrElementTransformerVoid() {
+    private var currentBuilder: IrBuilderWithScope? = null
+
+    protected val builder: IrBuilderWithScope
+        get() = currentBuilder!!
+
+    private inline fun <T> withBuilder(declarationDescriptor: DeclarationDescriptor, block: () -> T): T {
+        val oldBuilder = currentBuilder
+        currentBuilder = context.createIrBuilder(declarationDescriptor)
+        return try {
+            block()
+        } finally {
+            currentBuilder = oldBuilder
+        }
+    }
+
+    override fun visitFunction(declaration: IrFunction): IrStatement {
+        withBuilder(declaration.descriptor) {
+            return super.visitFunction(declaration)
+        }
+    }
+
+    override fun visitField(declaration: IrField): IrStatement {
+        withBuilder(declaration.descriptor) {
+            // Transforms initializer:
+            return super.visitField(declaration)
+        }
+    }
+
+    override fun visitAnonymousInitializer(declaration: IrAnonymousInitializer): IrStatement {
+        withBuilder(declaration.descriptor) {
+            return super.visitAnonymousInitializer(declaration)
+        }
+    }
+}
+
 fun computeOverrides(current: ClassDescriptor, functionsFromCurrent: List<CallableMemberDescriptor>): List<DeclarationDescriptor> {
 
     val result = mutableListOf<DeclarationDescriptor>()

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

@@ -62,7 +62,7 @@ internal class KonanLower(val context: Context) {
             Autoboxing(context).lower(irFile)
         }
         phaser.phase(KonanPhase.LOWER_INTEROP) {
-            InteropLowering(context).runOnFilePostfix(irFile)
+            InteropLowering(context).lower(irFile)
         }
     }
 }

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

@@ -1,8 +1,8 @@
 package org.jetbrains.kotlin.backend.konan.lower
 
-import org.jetbrains.kotlin.backend.common.FunctionLoweringPass
+import org.jetbrains.kotlin.backend.common.FileLoweringPass
+import org.jetbrains.kotlin.backend.common.lower.IrBuildingTransformer
 import org.jetbrains.kotlin.backend.common.lower.at
-import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.konan.Context
 import org.jetbrains.kotlin.backend.konan.ValueType
 import org.jetbrains.kotlin.backend.konan.isRepresentedAs
@@ -12,12 +12,9 @@ import org.jetbrains.kotlin.ir.builders.IrBuilder
 import org.jetbrains.kotlin.ir.builders.IrBuilderWithScope
 import org.jetbrains.kotlin.ir.builders.irCall
 import org.jetbrains.kotlin.ir.builders.irGet
-import org.jetbrains.kotlin.ir.declarations.IrFunction
-import org.jetbrains.kotlin.ir.expressions.IrCall
-import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.expressions.IrTypeOperatorCall
+import org.jetbrains.kotlin.ir.declarations.IrFile
+import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetObjectValueImpl
-import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.OverridingUtil
@@ -29,16 +26,15 @@ import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
 /**
  * Lowers some interop intrinsic calls.
  */
-internal class InteropLowering(val context: Context) : FunctionLoweringPass {
-    override fun lower(irFunction: IrFunction) {
-        val transformer = InteropTransformer(context, irFunction.descriptor)
-        irFunction.transformChildrenVoid(transformer)
+internal class InteropLowering(val context: Context) : FileLoweringPass {
+    override fun lower(irFile: IrFile) {
+        val transformer = InteropTransformer(context)
+        irFile.transformChildrenVoid(transformer)
     }
 }
 
-private class InteropTransformer(val context: Context, val function: FunctionDescriptor) : IrElementTransformerVoid() {
+private class InteropTransformer(val context: Context) : IrBuildingTransformer(context) {
 
-    val builder = context.createIrBuilder(function)
     val interop = context.interopBuiltIns
 
     private fun MemberScope.getSingleContributedFunction(name: String,