Add ir generation plugins to JS and JVM BE

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/compiler.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.backend.js
 
 import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
+import org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension
 import org.jetbrains.kotlin.backend.common.lower.*
 import org.jetbrains.kotlin.backend.common.runOnFilePostfix
 import org.jetbrains.kotlin.config.CompilerConfiguration
@@ -60,6 +61,11 @@ fun compile(
     ExternalDependenciesGenerator(psi2IrContext.moduleDescriptor, psi2IrContext.symbolTable, psi2IrContext.irBuiltIns)
         .generateUnboundSymbolsAsDependencies(moduleFragment)
 
+    val extensions = IrGenerationExtension.getInstances(project)
+    extensions.forEach { extension ->
+        moduleFragment.files.forEach { irFile -> extension.generate(irFile, context, psi2IrContext.bindingContext) }
+    }
+
     MoveExternalDeclarationsToSeparatePlace().lower(moduleFragment.files)
 
     context.performInlining(moduleFragment)

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

@@ -16,16 +16,20 @@
 
 package org.jetbrains.kotlin.backend.jvm
 
+import org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.util.render
 import java.lang.AssertionError
 
-class JvmBackend(context: JvmBackendContext) {
+class JvmBackend(val context: JvmBackendContext) {
     private val lower = JvmLower(context)
     private val codegen = JvmCodegen(context)
 
     fun generateFile(irFile: IrFile) {
+        val extensions = IrGenerationExtension.getInstances(context.state.project)
+        extensions.forEach { it.generate(irFile, context, context.state.bindingContext) }
+
         lower.lower(irFile)
 
         for (loweredClass in irFile.declarations) {