[FIR] Add ability to provide additional synthetic declarations to metadata from plugins

^KT-55885 Fixed
2023-01-31 12:42:14 +02:00
parent 8350226bad
commit 1248ee12d6
3 changed files with 125 additions and 7 deletions
@@ -0,0 +1,75 @@
+/*
+ * 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.fir.extensions
+
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.declarations.FirClass
+import org.jetbrains.kotlin.fir.declarations.FirDeclaration
+import org.jetbrains.kotlin.fir.resolve.ScopeSession
+import org.jetbrains.kotlin.name.FqName
+import kotlin.reflect.KClass
+
+/**
+ * This extension can be used to provide information about declarations, which should be written in Kotlin metadata (i.e. be part of a module's ABI),
+ *   but for some reason can not (or should not) be generated with [FirDeclarationGenerationExtension]
+ *
+ * Example: assume your plugin generates some constructor in [IrGenerationExtension] which have value parameters matching
+ *   all properties of a class, and this constructor is used only as an implementation detail (so the only actor who accesses it
+ *   is a plugin itself). The constructor should be accessible from another module, so it should be present in the metadata. But you
+ *   can not generate this constructor in [FirDeclarationGenerationExtension], because it depends on types of properties,
+ *   which may be not resolved at the moment of constructor creation.
+ *
+ *
+ *   // MODULE: a
+ *   open class Base {
+ *       val x: Int = 1
+ *       val y = "hello"
+ *
+ *       constructor()
+ *
+ *       // generated
+ *       constructor(x: Int, y: String) { ... } // (1)
+ *   }
+ *
+ *   // MODULE: b(a)
+ *   class Derived : Base {
+ *       val z = 1.0
+ *
+ *       constructor() : super()
+ *
+ *       // generated
+ *       constructor(x: Int, y: String, z: Double) : super(x, y) { ... } // (2)
+ *
+ *       // constructor (1) should be presented in metadata of class Base, so IR plugin
+ *       //  can reference it during generation of constructor (2)
+ *  }
+ *
+ * All declarations provided by this extension should be fully resolved and contain all sub declarations if they exist.
+ *   E.g. if you want to provide some class then this class should contain all declarations of this class you want to be
+ *   present in metadata in `declarations` field of a `FirRegularClass`.
+ *   [FirDeclarationGenerationExtension] won't be called for classes provided by this extension.
+ */
+abstract class FirDeclarationsForMetadataProviderExtension(session: FirSession) : FirExtension(session) {
+    companion object {
+        val NAME = FirExtensionPointName("SyntheticDeclarationsForMetadataGenerationExtension")
+    }
+
+    final override val name: FirExtensionPointName
+        get() = NAME
+
+    final override val extensionType: KClass<out FirExtension> = FirDeclarationsForMetadataProviderExtension::class
+
+    /**
+     * It's allowed to provide only functions, properties and type aliases
+     */
+    open fun provideTopLevelDeclarations(packageFqName: FqName, scopeSession: ScopeSession): List<FirDeclaration> = emptyList()
+
+    open fun provideDeclarationsForClass(klass: FirClass, scopeSession: ScopeSession): List<FirDeclaration> = emptyList()
+
+    fun interface Factory : FirExtension.Factory<FirDeclarationsForMetadataProviderExtension>
+}
+
+val FirExtensionService.declarationForMetadataProviders: List<FirDeclarationsForMetadataProviderExtension> by FirExtensionService.registeredExtensions()