JVM IR: Create local classes in PropertyReferenceLowering

In particular, we should not cache classes or instances for property
references, since they may be used inside of inline funtions. This also
allows us to mark the $$delegatedProperties array as package private.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/InterfaceLowering.kt

@@ -82,6 +82,16 @@ private class InterfaceLowering(val context: JvmBackendContext) : IrElementTrans
             context.localDelegatedProperties[defaultImplsIrClass.attributeOwnerId as IrClass] = localDelegatedProperties
             context.localDelegatedProperties[irClass.attributeOwnerId as IrClass] = emptyList<IrLocalDelegatedPropertySymbol>()
         }
+
+        // Move $$delegatedProperties array
+        val delegatedPropertyArray = irClass.declarations.filterIsInstance<IrField>()
+            .singleOrNull { it.origin == JvmLoweredDeclarationOrigin.GENERATED_PROPERTY_REFERENCE }
+        if (delegatedPropertyArray != null) {
+            irClass.declarations.remove(delegatedPropertyArray)
+            defaultImplsIrClass.declarations.add(0, delegatedPropertyArray)
+            delegatedPropertyArray.parent = defaultImplsIrClass
+            delegatedPropertyArray.initializer?.patchDeclarationParents(defaultImplsIrClass)
+        }
     }
 
     private fun shouldRemoveFunction(function: IrFunction): Boolean =

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/PropertyReferenceLowering.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
 import org.jetbrains.kotlin.backend.jvm.ir.createJvmIrBuilder
 import org.jetbrains.kotlin.backend.jvm.ir.irArrayOf
+import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.addFunction
@@ -29,6 +30,7 @@ import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
 import org.jetbrains.kotlin.ir.types.impl.makeTypeProjection
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
+import org.jetbrains.kotlin.load.java.JavaVisibilities
 import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.types.Variance
@@ -135,20 +137,17 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
             propertyReferenceKind(!it.isFinal, if (it.isStatic || expression.dispatchReceiver != null) 0 else 1)
         } ?: throw AssertionError("property has no getter and no field: ${expression.dump()}")
 
-    private data class PropertyCacheKey(val symbol: IrSymbol, val reflected: Boolean)
-    private data class PropertyClassCacheKey(val symbol: IrSymbol, val boundReceiver: Boolean)
     private data class PropertyInstance(val initializer: IrExpression, val index: Int)
 
     override fun lower(irClass: IrClass) {
-        val kProperties = mutableMapOf<PropertyCacheKey, PropertyInstance>()
-        val kPropertyClasses = mutableMapOf<PropertyClassCacheKey, IrClass>()
+        val kProperties = mutableMapOf<IrSymbol, PropertyInstance>()
         val kPropertiesField = buildField {
             name = Name.identifier(JvmAbi.DELEGATED_PROPERTIES_ARRAY_NAME)
             type = kPropertiesFieldType
             origin = JvmLoweredDeclarationOrigin.GENERATED_PROPERTY_REFERENCE
             isFinal = true
             isStatic = true
-            // TODO: make the visibility package-local. Currently it's more permissive to allow access from inline functions.
+            visibility = JavaVisibilities.PACKAGE_VISIBILITY
         }
         var localPropertiesInClass = 0
 
@@ -165,20 +164,14 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
                 cachedKProperty(expression)
 
             private fun cachedKProperty(expression: IrCallableReference): IrExpression {
-                // Reflected implementation does not support partial application; also, cannot cache instances with arguments.
-                if (expression.dispatchReceiver != null || expression.extensionReceiver != null)
+                if (expression.origin != IrStatementOrigin.PROPERTY_REFERENCE_FOR_DELEGATE)
                     return createSpecializedKProperty(expression)
 
                 // For delegated properties, the getter and setter contain a reference each as the second argument to getValue
                 // and setValue. Since it's highly unlikely that anyone will call get/set on these, optimize for space.
-                val useReflectedImpl = expression.origin == IrStatementOrigin.PROPERTY_REFERENCE_FOR_DELEGATE
                 return context.createIrBuilder(currentScope!!.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset).run {
-                    val (_, index) = kProperties.getOrPut(PropertyCacheKey(expression.symbol, useReflectedImpl)) {
-                        val kProperty = if (useReflectedImpl)
-                            createReflectedKProperty(expression)
-                        else
-                            createSpecializedKProperty(expression)
-                        PropertyInstance(kProperty, kProperties.size)
+                    val (_, index) = kProperties.getOrPut(expression.symbol) {
+                        PropertyInstance(createReflectedKProperty(expression), kProperties.size)
                     }
                     irCall(arrayItemGetter).apply {
                         dispatchReceiver = irGetField(null, kPropertiesField)
@@ -218,17 +211,16 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
             // and then `C()::property` -> `C$property$0(C())`.
             //
             private fun createSpecializedKProperty(expression: IrCallableReference): IrExpression {
-                val bound = expression.dispatchReceiver != null || expression.extensionReceiver != null
-                val referenceClass = kPropertyClasses.getOrPut(PropertyClassCacheKey(expression.symbol, bound)) {
-                    createKPropertySubclass(expression)
-                }
-                return context.createIrBuilder(currentScope!!.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset).run {
-                    irCall(referenceClass.constructors.single()).apply {
-                        var index = 0
-                        expression.dispatchReceiver?.let { putValueArgument(index++, it) }
-                        expression.extensionReceiver?.let { putValueArgument(index++, it) }
+                val referenceClass = createKPropertySubclass(expression)
+                return context.createIrBuilder(currentScope!!.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset)
+                    .irBlock {
+                        +referenceClass
+                        +irCall(referenceClass.constructors.single()).apply {
+                            var index = 0
+                            expression.dispatchReceiver?.let { putValueArgument(index++, it) }
+                            expression.extensionReceiver?.let { putValueArgument(index++, it) }
+                        }
                     }
-                }
             }
 
             private fun createKPropertySubclass(expression: IrCallableReference): IrClass {
@@ -237,6 +229,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
                     setSourceRange(expression)
                     name = Name.special("<property reference to ${(expression.symbol.owner as IrDeclarationWithName).fqNameWhenAvailable}>")
                     origin = JvmLoweredDeclarationOrigin.GENERATED_PROPERTY_REFERENCE
+                    visibility = Visibilities.LOCAL
                 }.apply {
                     parent = irClass
                     superTypes += IrSimpleTypeImpl(superClass.symbol, false, listOf(), listOf())
@@ -317,7 +310,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
         })
 
         // Put the new field at the beginning so that static delegated properties with initializers work correctly.
-        // Since we do not cache property references with bound receivers, the new field does not reference anything else.
+        // Since we do not cache property references, the new field does not reference anything else.
         if (kProperties.isNotEmpty()) {
             irClass.declarations.add(0, kPropertiesField.apply {
                 parent = irClass
@@ -328,8 +321,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
             })
 
             context.localDelegatedProperties[irClass.attributeOwnerId as IrClass] =
-                kProperties.mapNotNull { it.key.symbol as? IrLocalDelegatedPropertySymbol }
+                kProperties.keys.filterIsInstance<IrLocalDelegatedPropertySymbol>()
         }
-        irClass.declarations.addAll(0, kPropertyClasses.values)
     }
 }

compiler/testData/writeFlags/callableReference/visibility/propertyReference.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 class A {
     val foo = ""