[FIR2IR] Make ExternalPackageParentPatcher a lowering

This is needed for two reasons:
1. Consistency
2. It should run after compiler plugins, which are now runs after fir2ir
   is finished for all modules

^KT-56173

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ExternalPackageParentPatcher.kt

@@ -1,43 +0,0 @@
-/*
- * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.fir.backend
-
-import org.jetbrains.kotlin.ir.IrElement
-import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
-import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
-import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
-
-// TODO: should be a lowering
-internal class ExternalPackageParentPatcher(
-    private val components: Fir2IrComponents,
-    private val fir2IrExtensions: Fir2IrExtensions
-) : IrElementVisitorVoid {
-    override fun visitElement(element: IrElement) {
-        element.acceptChildrenVoid(this)
-    }
-
-    override fun visitMemberAccess(expression: IrMemberAccessExpression<*>) {
-        super.visitMemberAccess(expression)
-        val callee = expression.symbol.owner as? IrMemberWithContainerSource ?: return
-        if (callee.parent is IrExternalPackageFragment) {
-            val parentClass = fir2IrExtensions.generateOrGetFacadeClass(callee, components) ?: return
-            parentClass.parent = callee.parent
-            callee.parent = parentClass
-            when (callee) {
-                is IrProperty -> handleProperty(callee, parentClass)
-                is IrSimpleFunction -> callee.correspondingPropertySymbol?.owner?.let { handleProperty(it, parentClass) }
-            }
-        }
-    }
-
-    private fun handleProperty(property: IrProperty, newParent: IrClass) {
-        property.parent = newParent
-        property.getter?.parent = newParent
-        property.setter?.parent = newParent
-        property.backingField?.parent = newParent
-    }
-}

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.fir.backend
 
 import org.jetbrains.kotlin.KtPsiSourceFileLinesMapping
 import org.jetbrains.kotlin.KtSourceFileLinesMappingFromLineStartOffsets
-import org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension
 import org.jetbrains.kotlin.builtins.DefaultBuiltIns
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.config.AnalysisFlags
@@ -32,12 +31,9 @@ import org.jetbrains.kotlin.ir.interpreter.IrInterpreter
 import org.jetbrains.kotlin.ir.interpreter.IrInterpreterConfiguration
 import org.jetbrains.kotlin.ir.interpreter.IrInterpreterEnvironment
 import org.jetbrains.kotlin.ir.interpreter.checker.EvaluationMode
-import org.jetbrains.kotlin.ir.interpreter.transformer.preprocessForConstTransformer
 import org.jetbrains.kotlin.ir.interpreter.transformer.transformConst
 import org.jetbrains.kotlin.ir.util.KotlinMangler
 import org.jetbrains.kotlin.ir.util.NaiveSourceBasedFileEntryImpl
-import org.jetbrains.kotlin.ir.visitors.acceptVoid
-import org.jetbrains.kotlin.platform.isJs
 import org.jetbrains.kotlin.psi.KtFile
 
 class Fir2IrConverter(
@@ -54,7 +50,6 @@ class Fir2IrConverter(
         allFirFiles: List<FirFile>,
         irModuleFragment: IrModuleFragmentImpl,
         fir2irVisitor: Fir2IrVisitor,
-        fir2IrExtensions: Fir2IrExtensions,
         runPreCacheBuiltinClasses: Boolean
     ) {
         session.lazyDeclarationResolver.disableLazyResolveContractChecks()
@@ -98,8 +93,6 @@ class Fir2IrConverter(
         }
 
         evaluateConstants(irModuleFragment, configuration)
-
-        irModuleFragment.acceptVoid(ExternalPackageParentPatcher(components, fir2IrExtensions))
     }
 
     fun bindFakeOverridesOrPostpone(declarations: List<IrDeclaration>) {
@@ -499,8 +492,7 @@ class Fir2IrConverter(
             }
 
             converter.runSourcesConversion(
-                allFirFiles, irModuleFragment, fir2irVisitor, fir2IrExtensions,
+                allFirFiles, irModuleFragment, fir2irVisitor, runPreCacheBuiltinClasses = initializedIrBuiltIns == null
-                runPreCacheBuiltinClasses = initializedIrBuiltIns == null
             )
 
             return Fir2IrResult(irModuleFragment, components, moduleDescriptor)

compiler/ir/backend.jvm/entrypoint/src/org/jetbrains/kotlin/backend/jvm/JvmIrCodegenFactory.kt

@@ -331,7 +331,8 @@ open class JvmIrCodegenFactory(
         val phases = if (evaluatorFragmentInfoForPsi2Ir != null) jvmFragmentLoweringPhases else jvmLoweringPhases
         val phaseConfig = customPhaseConfig ?: PhaseConfig(phases)
         val context = JvmBackendContext(
-            state, irModuleFragment.irBuiltins, symbolTable, phaseConfig, extensions, backendExtension, irSerializer, irPluginContext
+            state, irModuleFragment.irBuiltins, symbolTable, phaseConfig, extensions,
+            backendExtension, irSerializer, JvmIrDeserializerImpl(), irProviders, irPluginContext
         )
         if (evaluatorFragmentInfoForPsi2Ir != null) {
             context.localDeclarationsLoweringData = mutableMapOf()

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

@@ -473,7 +473,8 @@ private fun buildJvmLoweringPhases(
         nlevels = 1,
         actions = setOf(defaultDumper, validationAction),
         lower =
-        fragmentSharedVariablesLowering then
+        externalPackageParentPatcherPhase then
+                fragmentSharedVariablesLowering then
                 validateIrBeforeLowering then
                 processOptionalAnnotationsPhase then
                 expectDeclarationsRemovingPhase then

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

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.jvm.lower
+
+import org.jetbrains.kotlin.backend.common.CommonBackendContext
+import org.jetbrains.kotlin.backend.common.FileLoweringPass
+import org.jetbrains.kotlin.backend.common.phaser.makeIrModulePhase
+import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
+import org.jetbrains.kotlin.backend.jvm.JvmFileFacadeClass
+import org.jetbrains.kotlin.config.CommonConfigurationKeys
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
+import org.jetbrains.kotlin.ir.util.createParameterDeclarations
+import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
+import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
+import org.jetbrains.kotlin.ir.visitors.acceptVoid
+import org.jetbrains.kotlin.load.kotlin.FacadeClassSource
+
+internal val externalPackageParentPatcherPhase = makeIrModulePhase(
+    ::createLowering,
+    name = "ExternalPackageParentPatcherLowering",
+    description = "Replace parent from package fragment to FileKt class for top-level callables (K2 only)"
+)
+
+private fun createLowering(context: CommonBackendContext): FileLoweringPass {
+    require(context is JvmBackendContext)
+    return when (context.configuration[CommonConfigurationKeys.USE_FIR]) {
+        true -> ExternalPackageParentPatcherLowering(context)
+        false, null -> FileLoweringPass.Empty
+    }
+}
+
+class ExternalPackageParentPatcherLowering(val context: JvmBackendContext) : FileLoweringPass {
+    override fun lower(irFile: IrFile) {
+        irFile.acceptVoid(Visitor())
+    }
+
+    private inner class Visitor : IrElementVisitorVoid {
+        override fun visitElement(element: IrElement) {
+            element.acceptChildrenVoid(this)
+        }
+
+        override fun visitMemberAccess(expression: IrMemberAccessExpression<*>) {
+            visitElement(expression)
+            val callee = expression.symbol.owner as? IrMemberWithContainerSource ?: return
+            if (callee.parent is IrExternalPackageFragment) {
+                val parentClass = generateOrGetFacadeClass(callee) ?: return
+                parentClass.parent = callee.parent
+                callee.parent = parentClass
+                when (callee) {
+                    is IrProperty -> handleProperty(callee, parentClass)
+                    is IrSimpleFunction -> callee.correspondingPropertySymbol?.owner?.let { handleProperty(it, parentClass) }
+                }
+            }
+        }
+
+        private fun generateOrGetFacadeClass(declaration: IrMemberWithContainerSource): IrClass? {
+            val deserializedSource = declaration.containerSource ?: return null
+            if (deserializedSource !is FacadeClassSource) return null
+            val facadeName = deserializedSource.facadeClassName ?: deserializedSource.className
+            return JvmFileFacadeClass(
+                if (deserializedSource.facadeClassName != null) IrDeclarationOrigin.JVM_MULTIFILE_CLASS else IrDeclarationOrigin.FILE_CLASS,
+                facadeName.fqNameForTopLevelClassMaybeWithDollars.shortName(),
+                deserializedSource,
+                deserializeIr = { irClass -> deserializeTopLevelClass(irClass) }
+            ).also {
+                it.createParameterDeclarations()
+                context.classNameOverride[it] = facadeName
+            }
+        }
+
+        private fun deserializeTopLevelClass(irClass: IrClass): Boolean {
+            return context.irDeserializer.deserializeTopLevelClass(
+                irClass, context.irBuiltIns, context.symbolTable, context.irProviders, context.generatorExtensions
+            )
+        }
+
+        private fun handleProperty(property: IrProperty, newParent: IrClass) {
+            property.parent = newParent
+            property.getter?.parent = newParent
+            property.setter?.parent = newParent
+            property.backingField?.parent = newParent
+        }
+    }
+}

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

@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.ir.expressions.impl.IrBlockBodyImpl
 import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.name.Name
 
+
 internal val typeAliasAnnotationMethodsPhase = makeIrFilePhase(
     ::TypeAliasAnnotationMethodsLowering,
     name = "TypeAliasAnnotationMethodsLowering",

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt

@@ -31,8 +31,8 @@ import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
+import org.jetbrains.kotlin.ir.linkage.IrProvider
 import org.jetbrains.kotlin.ir.symbols.*
-import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.IrTypeSystemContext
 import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.util.*
@@ -49,6 +49,8 @@ class JvmBackendContext(
     val generatorExtensions: JvmGeneratorExtensions,
     val backendExtension: JvmBackendExtension,
     val irSerializer: JvmIrSerializer?,
+    val irDeserializer: JvmIrDeserializer,
+    val irProviders: List<IrProvider>,
     val irPluginContext: IrPluginContext?,
 ) : CommonBackendContext {
 
@@ -63,12 +65,17 @@ class JvmBackendContext(
         generatorExtensions: JvmGeneratorExtensions,
         backendExtension: JvmBackendExtension,
         irSerializer: JvmIrSerializer?,
-    ) : this(state, irBuiltIns, symbolTable, phaseConfig, generatorExtensions, backendExtension, irSerializer, null)
+        irProviders: List<IrProvider>,
+        irDeserializer: JvmIrDeserializer,
+    ) : this(
+        state, irBuiltIns, symbolTable, phaseConfig, generatorExtensions,
+        backendExtension, irSerializer, irDeserializer, irProviders, irPluginContext = null
+    )
 
     data class LocalFunctionData(
         val localContext: LocalDeclarationsLowering.LocalFunctionContext,
         val newParameterToOld: Map<IrValueParameter, IrValueParameter>,
-        val newParameterToCaptured: Map<IrValueParameter, IrValueSymbol>
+        val newParameterToCaptured: Map<IrValueParameter, IrValueSymbol>,
     )
 
     // If not-null, this is populated by LocalDeclarationsLowering with the intermediate data
@@ -219,7 +226,7 @@ class JvmBackendContext(
     override fun handleDeepCopy(
         fileSymbolMap: MutableMap<IrFileSymbol, IrFileSymbol>,
         classSymbolMap: MutableMap<IrClassSymbol, IrClassSymbol>,
-        functionSymbolMap: MutableMap<IrSimpleFunctionSymbol, IrSimpleFunctionSymbol>
+        functionSymbolMap: MutableMap<IrSimpleFunctionSymbol, IrSimpleFunctionSymbol>,
     ) {
         val oldClassesWithNameOverride = classNameOverride.keys.toList()
         for (klass in oldClassesWithNameOverride) {
@@ -290,7 +297,7 @@ class JvmBackendContext(
         get() = false
 
     inner class JvmIr(
-        symbolTable: SymbolTable
+        symbolTable: SymbolTable,
     ) : Ir<JvmBackendContext>(this) {
         override val symbols = JvmSymbols(this@JvmBackendContext, symbolTable)
 
@@ -300,7 +307,7 @@ class JvmBackendContext(
     override fun remapMultiFieldValueClassStructure(
         oldFunction: IrFunction,
         newFunction: IrFunction,
-        parametersMappingOrNull: Map<IrValueParameter, IrValueParameter>?
+        parametersMappingOrNull: Map<IrValueParameter, IrValueParameter>?,
     ) {
         val parametersMapping = parametersMappingOrNull ?: run {
             require(oldFunction.explicitParametersCount == newFunction.explicitParametersCount) {

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/backend/handlers/IrInlineBodiesHandler.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.test.backend.handlers
 
 import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.declarations.IrExternalPackageFragment
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
 import org.jetbrains.kotlin.ir.declarations.lazy.AbstractIrLazyFunction
 import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
@@ -16,6 +17,7 @@ import org.jetbrains.kotlin.ir.util.resolveFakeOverride
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.test.backend.ir.IrBackendInput
+import org.jetbrains.kotlin.test.model.FrontendKinds
 import org.jetbrains.kotlin.test.model.TestModule
 import org.jetbrains.kotlin.test.services.TestServices
 
@@ -25,7 +27,7 @@ class IrInlineBodiesHandler(testServices: TestServices) : AbstractIrHandler(test
     override fun processModule(module: TestModule, info: IrBackendInput) {
         info.processAllIrModuleFragments(module) { irModule, _ ->
             irModule.acceptChildrenVoid(InlineFunctionsCollector())
-            irModule.acceptChildrenVoid(InlineCallBodiesCheck())
+            irModule.acceptChildrenVoid(InlineCallBodiesCheck(firEnabled = module.frontendKind == FrontendKinds.FIR))
         }
 
         assertions.assertTrue((info as IrBackendInput.JvmIrBackendInput).backendInput.symbolTable.allUnbound.isEmpty())
@@ -46,7 +48,7 @@ class IrInlineBodiesHandler(testServices: TestServices) : AbstractIrHandler(test
         }
     }
 
-    inner class InlineCallBodiesCheck : IrElementVisitorVoid {
+    inner class InlineCallBodiesCheck(val firEnabled: Boolean) : IrElementVisitorVoid {
         override fun visitElement(element: IrElement) {
             element.acceptChildrenVoid(this)
         }
@@ -68,7 +70,14 @@ class IrInlineBodiesHandler(testServices: TestServices) : AbstractIrHandler(test
             if (this !is AbstractIrLazyFunction) return body != null
             if (!isDeserializationEnabled) return false
             if (!isInline || isFakeOverride) return false
-            return getTopLevelDeclaration() is DeserializableClass
+            val topLevelDeclaration = getTopLevelDeclaration()
+            if (topLevelDeclaration is DeserializableClass) return true
+            return when (firEnabled) {
+                // In compilation with FIR parents of external top-levels functions are replaced
+                //   in lowerings, not in fir2ir converter
+                true -> topLevelDeclaration.parent is IrExternalPackageFragment
+                false -> false
+            }
         }
     }
 }