[JS IR] Use non-persistent IR for non-dce-driven mode

Eliminate overhead of persistency that we don't use in this mode.

compiler/ir/backend.js/build.gradle.kts

@@ -13,6 +13,7 @@ dependencies {
     compile(project(":compiler:ir.serialization.common"))
     compile(project(":compiler:ir.serialization.js"))
     compile(project(":compiler:ir.tree.persistent"))
+    compile(project(":compiler:ir.tree.impl"))
     compile(project(":js:js.ast"))
     compile(project(":js:js.frontend"))
 

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

@@ -20,8 +20,8 @@ import org.jetbrains.kotlin.ir.backend.js.utils.*
 import org.jetbrains.kotlin.ir.builders.declarations.addFunction
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrExternalPackageFragmentImpl
+import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrFileImpl
-import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.symbols.impl.DescriptorlessExternalPackageFragmentSymbol
@@ -45,6 +45,7 @@ class JsIrBackendContext(
     override val scriptMode: Boolean = false,
     override val es6mode: Boolean = false,
     val propertyLazyInitialization: Boolean = false,
+    override val irFactory: IrFactory = IrFactoryImpl
 ) : JsCommonBackendContext {
     val fileToInitializationFuns: MutableMap<IrFile, IrSimpleFunction?> = mutableMapOf()
     val fileToInitializerPureness: MutableMap<IrFile, Boolean> = mutableMapOf()
@@ -55,8 +56,6 @@ class JsIrBackendContext(
 
     override var inVerbosePhase: Boolean = false
 
-    override val irFactory: IrFactory = PersistentIrFactory
-
     val devMode = configuration[JSConfigurationKeys.DEVELOPER_MODE] ?: false
     val errorPolicy = configuration[JSConfigurationKeys.ERROR_TOLERANCE_POLICY] ?: ErrorTolerancePolicy.DEFAULT
 

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

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.ir.backend.js.transformers.irToJs.IrModuleToJsTransf
 import org.jetbrains.kotlin.ir.backend.js.utils.NameTables
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.declarations.StageController
+import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
 import org.jetbrains.kotlin.ir.declarations.stageController
 import org.jetbrains.kotlin.ir.util.ExternalDependenciesGenerator
@@ -53,8 +54,10 @@ fun compile(
 ): CompilerResult {
     stageController = StageController()
 
+    val irFactory = if (dceDriven) PersistentIrFactory else IrFactoryImpl
+
     val (moduleFragment: IrModuleFragment, dependencyModules, irBuiltIns, symbolTable, deserializer) =
-        loadIr(project, mainModule, analyzer, configuration, allDependencies, friendDependencies, PersistentIrFactory)
+        loadIr(project, mainModule, analyzer, configuration, allDependencies, friendDependencies, irFactory)
 
     val moduleDescriptor = moduleFragment.descriptor
 
@@ -72,6 +75,7 @@ fun compile(
         configuration,
         es6mode = es6mode,
         propertyLazyInitialization = propertyLazyInitialization,
+        irFactory = irFactory
     )
 
     // Load declarations referenced during `context` initialization