Fix initialization order of enum with companion object in JS BE

Make enum entries initialize before companion object. This helps
in situation when companion object initializer refers to enum fields.
JVM be generates <clinit> method which first initializes all enum fields
and then runs companion object initializer. This commit introduces the
similar behaviour in JS BE. The old behaviour was: initialize companion
object in constructor. In enum, constructor is called to initialize
enum fields, so previously companion object was initialized first,
which is incorrect.

See KT-16745

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -8154,6 +8154,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             doTest(fileName);
         }
 
+        @TestMetadata("enumCompanionInit.kt")
+        public void testEnumCompanionInit() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumCompanionInit.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("enumInheritedFromTrait.kt")
         public void testEnumInheritedFromTrait() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/enumInheritedFromTrait.kt");

js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/AbstractDeclarationVisitor.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.isOverridable
 import org.jetbrains.kotlin.js.backend.ast.JsExpression
+import org.jetbrains.kotlin.js.backend.ast.JsName
 import org.jetbrains.kotlin.js.translate.context.TranslationContext
 import org.jetbrains.kotlin.js.translate.expression.translateAndAliasParameters
 import org.jetbrains.kotlin.js.translate.expression.translateFunction
@@ -34,8 +35,11 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.isExtensionProperty
 abstract class AbstractDeclarationVisitor : TranslatorVisitor<Unit>()  {
     override fun emptyResult(context: TranslationContext) { }
 
+    open val enumInitializerName: JsName?
+        get() = null
+
     override fun visitClassOrObject(classOrObject: KtClassOrObject, context: TranslationContext) {
-        ClassTranslator.translate(classOrObject, context)
+        ClassTranslator.translate(classOrObject, context, enumInitializerName)
         val descriptor = BindingUtils.getClassDescriptor(context.bindingContext(), classOrObject)
         context.export(descriptor)
     }

js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/ClassTranslator.kt

@@ -92,6 +92,12 @@ class ClassTranslator private constructor(
         constructorFunction.body.statements += bodyVisitor.initializerStatements
         delegationTranslator.generateDelegated()
 
+        val companionDescriptor = descriptor.companionObjectDescriptor
+        if (enumInitFunction != null && companionDescriptor != null) {
+            val initInvocation = JsInvocation(JsAstUtils.pureFqn(context().getNameForObjectInstance(companionDescriptor), null))
+            enumInitFunction.body.statements += JsAstUtils.asSyntheticStatement(initInvocation)
+        }
+
         translatePrimaryConstructor(constructorFunction, context, delegationTranslator)
         addMetadataObject()
         addMetadataType()
@@ -446,7 +452,10 @@ class ClassTranslator private constructor(
         val instanceFun = context().createRootScopedFunction("Instance function: " + descriptor)
         instanceFun.name = context().getNameForObjectInstance(descriptor)
 
-        if (enumInitializerName == null) {
+        if (enumInitializerName != null) {
+            instanceFun.body.statements += JsInvocation(pureFqn(enumInitializerName, null)).makeStmt()
+        }
+        if (descriptor.kind != ClassKind.ENUM_ENTRY) {
             val instanceCreatedCondition = JsAstUtils.equality(cachedInstanceName.makeRef(), JsLiteral.NULL)
             val instanceCreationBlock = JsBlock()
             val instanceCreatedGuard = JsIf(instanceCreatedCondition, instanceCreationBlock)
@@ -455,9 +464,6 @@ class ClassTranslator private constructor(
             val objectRef = context().getInnerReference(descriptor)
             instanceCreationBlock.statements += JsNew(objectRef).makeStmt()
         }
-        else {
-            instanceFun.body.statements += JsInvocation(pureFqn(enumInitializerName, null)).makeStmt()
-        }
 
         instanceFun.body.statements += JsReturn(cachedInstanceName.makeRef())
 
@@ -534,8 +540,8 @@ class ClassTranslator private constructor(
     }
 
     companion object {
-        @JvmStatic fun translate(classDeclaration: KtClassOrObject, context: TranslationContext) {
-            return ClassTranslator(classDeclaration, context, null, null).translate()
+        @JvmStatic fun translate(classDeclaration: KtClassOrObject, context: TranslationContext, enumInitializerName: JsName?) {
+            return ClassTranslator(classDeclaration, context, enumInitializerName, null).translate()
         }
 
         @JvmStatic fun translate(classDeclaration: KtEnumEntry, context: TranslationContext, enumInitializerName: JsName, ordinal: Int) {

js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/DeclarationBodyVisitor.kt

@@ -40,11 +40,14 @@ class DeclarationBodyVisitor(
     val initializerStatements = mutableListOf<JsStatement>()
     val enumEntries = mutableListOf<ClassDescriptor>()
 
+    override val enumInitializerName: JsName?
+        get() = enumInitializer?.name
+
     override fun visitClassOrObject(classOrObject: KtClassOrObject, context: TranslationContext) {
         super.visitClassOrObject(classOrObject, context)
 
         if (classOrObject is KtObjectDeclaration) {
-            if (classOrObject.isCompanion()) {
+            if (classOrObject.isCompanion() && containingClass.kind != ClassKind.ENUM_CLASS) {
                 val descriptor = BindingUtils.getDescriptorForElement(context.bindingContext(), classOrObject) as ClassDescriptor
                 addInitializerStatement(JsInvocation(context.getNameForObjectInstance(descriptor).makeRef()).makeStmt())
             }

js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/ExpressionVisitor.java

@@ -604,6 +604,6 @@ public final class ExpressionVisitor extends TranslatorVisitor<JsNode> {
     ) {
         JsScope scope = context.getScopeForDescriptor(descriptor);
         TranslationContext classContext = context.innerWithUsageTracker(scope, descriptor);
-        ClassTranslator.translate(declaration, classContext);
+        ClassTranslator.translate(declaration, classContext, null);
     }
 }