JVM IR, FIR: add JvmBackendExtension instead of MetadataSerializerFactory

This might be a better place for future behavior that should be
abstracted between FE 1.0 and FIR, in JVM IR.

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

@@ -19,7 +19,6 @@ import org.jetbrains.kotlin.backend.jvm.lower.CollectionStubComputer
 import org.jetbrains.kotlin.backend.jvm.lower.JvmInnerClassesSupport
 import org.jetbrains.kotlin.backend.jvm.lower.inlineclasses.InlineClassAbi
 import org.jetbrains.kotlin.backend.jvm.lower.inlineclasses.MemoizedInlineClassReplacements
-import org.jetbrains.kotlin.codegen.serialization.JvmSerializationBindings
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
@@ -41,8 +40,6 @@ import org.jetbrains.kotlin.psi2ir.PsiSourceManager
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
 import org.jetbrains.org.objectweb.asm.Type
 
-typealias MetadataSerializerFactory = (JvmBackendContext, IrClass, Type, JvmSerializationBindings, MetadataSerializer?) -> MetadataSerializer
-
 class JvmBackendContext(
     val state: GenerationState,
     val psiSourceManager: PsiSourceManager,
@@ -51,7 +48,7 @@ class JvmBackendContext(
     private val symbolTable: SymbolTable,
     val phaseConfig: PhaseConfig,
     val generatorExtensions: JvmGeneratorExtensions,
-    val serializerFactory: MetadataSerializerFactory
+    val backendExtension: JvmBackendExtension,
 ) : CommonBackendContext {
     // If the JVM fqname of a class differs from what is implied by its parent, e.g. if it's a file class
     // annotated with @JvmPackageName, the correct name is recorded here.

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

@@ -0,0 +1,30 @@
+/*
+ * 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.backend.jvm
+
+import org.jetbrains.kotlin.backend.jvm.codegen.DescriptorMetadataSerializer
+import org.jetbrains.kotlin.backend.jvm.codegen.MetadataSerializer
+import org.jetbrains.kotlin.codegen.serialization.JvmSerializationBindings
+import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.org.objectweb.asm.Type
+
+interface JvmBackendExtension {
+    fun createSerializer(
+        context: JvmBackendContext, klass: IrClass, type: Type, bindings: JvmSerializationBindings, parentSerializer: MetadataSerializer?
+    ): MetadataSerializer
+
+    object Default : JvmBackendExtension {
+        override fun createSerializer(
+            context: JvmBackendContext,
+            klass: IrClass,
+            type: Type,
+            bindings: JvmSerializationBindings,
+            parentSerializer: MetadataSerializer?
+        ): MetadataSerializer {
+            return DescriptorMetadataSerializer(context, klass, type, bindings, parentSerializer)
+        }
+    }
+}

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

@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.backend.common.extensions.IrPluginContextImpl
 import org.jetbrains.kotlin.backend.common.ir.BuiltinSymbolsBase
 import org.jetbrains.kotlin.backend.common.phaser.PhaseConfig
 import org.jetbrains.kotlin.backend.jvm.codegen.ClassCodegen
-import org.jetbrains.kotlin.backend.jvm.codegen.DescriptorMetadataSerializer
 import org.jetbrains.kotlin.backend.jvm.lower.MultifileFacadeFileEntry
 import org.jetbrains.kotlin.backend.jvm.serialization.JvmIdSignatureDescriptor
 import org.jetbrains.kotlin.codegen.CodegenFactory
@@ -120,7 +119,7 @@ class JvmIrCodegenFactory(private val phaseConfig: PhaseConfig) : CodegenFactory
 
         doGenerateFilesInternal(
             state, irModuleFragment, psi2irContext.symbolTable, psi2irContext.sourceManager, phaseConfig,
-            irProviders, extensions, ::DescriptorMetadataSerializer
+            irProviders, extensions, JvmBackendExtension.Default,
         )
     }
 
@@ -132,11 +131,11 @@ class JvmIrCodegenFactory(private val phaseConfig: PhaseConfig) : CodegenFactory
         phaseConfig: PhaseConfig,
         irProviders: List<IrProvider>,
         extensions: JvmGeneratorExtensions,
-        serializerFactory: MetadataSerializerFactory,
+        backendExtension: JvmBackendExtension,
     ) {
         val context = JvmBackendContext(
             state, sourceManager, irModuleFragment.irBuiltins, irModuleFragment,
-            symbolTable, phaseConfig, extensions, serializerFactory
+            symbolTable, phaseConfig, extensions, backendExtension
         )
         /* JvmBackendContext creates new unbound symbols, have to resolve them. */
         ExternalDependenciesGenerator(symbolTable, irProviders, state.languageVersionSettings).generateUnboundSymbolsAsDependencies()
@@ -178,7 +177,7 @@ class JvmIrCodegenFactory(private val phaseConfig: PhaseConfig) : CodegenFactory
         symbolTable: SymbolTable,
         sourceManager: PsiSourceManager,
         extensions: JvmGeneratorExtensions,
-        serializerFactory: MetadataSerializerFactory
+        backendExtension: JvmBackendExtension,
     ) {
         irModuleFragment.irBuiltins.functionFactory = IrFunctionFactory(irModuleFragment.irBuiltins, symbolTable)
         val irProviders = generateTypicalIrProviderList(
@@ -186,7 +185,7 @@ class JvmIrCodegenFactory(private val phaseConfig: PhaseConfig) : CodegenFactory
         )
 
         doGenerateFilesInternal(
-            state, irModuleFragment, symbolTable, sourceManager, phaseConfig, irProviders, extensions, serializerFactory
+            state, irModuleFragment, symbolTable, sourceManager, phaseConfig, irProviders, extensions, backendExtension,
         )
     }
 }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ClassCodegen.kt

@@ -190,7 +190,9 @@ class ClassCodegen private constructor(
     }
 
     private val metadataSerializer: MetadataSerializer =
-        context.serializerFactory(context, irClass, type, visitor.serializationBindings, parentClassCodegen?.metadataSerializer)
+        context.backendExtension.createSerializer(
+            context, irClass, type, visitor.serializationBindings, parentClassCodegen?.metadataSerializer
+        )
 
     private fun generateKotlinMetadataAnnotation() {
         // TODO: if `-Xmultifile-parts-inherit` is enabled, write the corresponding flag for parts and facades to [Metadata.extraInt].

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ClassCodegen.kt.201

@@ -190,7 +190,9 @@ class ClassCodegen private constructor(
     }
 
     private val metadataSerializer: MetadataSerializer =
-        context.serializerFactory(context, irClass, type, visitor.serializationBindings, parentClassCodegen?.metadataSerializer)
+        context.backendExtension.createSerializer(
+            context, irClass, type, visitor.serializationBindings, parentClassCodegen?.metadataSerializer
+        )
 
     private fun generateKotlinMetadataAnnotation() {
         // TODO: if `-Xmultifile-parts-inherit` is enabled, write the corresponding flag for parts and facades to [Metadata.extraInt].