[JS IR BE] Enum class lowering

libraries/stdlib/js/irRuntime/Enum.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin
+
+public class Enum<T : Enum<T>>(val name: String, val ordinal: Int) : Comparable<Enum<T>> {
+
+    override fun compareTo(other: Enum<T>) = ordinal.compareTo(other.ordinal)
+
+    override fun equals(other: Any?) = this === other
+
+    override fun hashCode(): Int = identityHashCode(this)
+
+    override fun toString() = name
+
+    companion object
+}

libraries/stdlib/js/irRuntime/core.kt

@@ -102,3 +102,6 @@ fun hashCode(obj: dynamic): Int {
     """
     ).unsafeCast<Int>()
 }
+
+// TODO: Use getObjectHashCode instead
+fun identityHashCode(obj: dynamic): Int = hashCode(obj)

libraries/stdlib/js/irRuntime/exceptions.kt

@@ -61,6 +61,9 @@ open class NoSuchElementException(message: String?, cause: Throwable?) : Runtime
 }
 
 // TODO: fix function names to satisfy style convention (depends on built-in names)
+fun THROW_ISE() {
+    throw IllegalStateException()
+}
 fun THROW_CCE() {
     throw ClassCastException()
 }