Introduced IR CodegenFactory, added configuration key to enable it

compiler/backend/backend.iml

@@ -13,5 +13,6 @@
     <orderEntry type="module" module-name="serialization" />
     <orderEntry type="module" module-name="backend-common" exported="" />
     <orderEntry type="module" module-name="util" />
+    <orderEntry type="module" module-name="backend.jvm" />
   </component>
 </module>

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.codegen.state
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.ModificationTracker
 import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.backend.jvm.JvmIrCodegenFactory
 import org.jetbrains.kotlin.builtins.ReflectionTypes
 import org.jetbrains.kotlin.codegen.*
 import org.jetbrains.kotlin.codegen.`when`.MappingsClassesForWhenByEnum
@@ -69,7 +70,7 @@ class GenerationState @JvmOverloads constructor(
         // TODO: get rid of it with the proper module infrastructure
         val outDirectory: File? = null,
         private val onIndependentPartCompilationEnd: GenerationStateEventCallback = GenerationStateEventCallback.DO_NOTHING,
-        val codegenFactory: CodegenFactory = DefaultCodegenFactory,
+        val codegenFactory: CodegenFactory = if (configuration.getBoolean(JVMConfigurationKeys.IR)) JvmIrCodegenFactory else DefaultCodegenFactory,
         wantsDiagnostics: Boolean = true
 ) {
     abstract class GenerateClassFilter {