[JS IR] Implement KProperty runtime utils

libraries/stdlib/js-ir/runtime/reflectRuntime.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * 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.js
+
+import kotlin.reflect.KProperty
+
+internal fun getPropertyCallableRef(name: String, paramCount: Int, type: dynamic, getter: dynamic, setter: dynamic): KProperty<*> {
+    getter.get = getter
+    getter.set = setter
+    getter.callableName = name
+    return getPropertyRefClass(getter, getKPropMetadata(paramCount, setter, type)).unsafeCast<KProperty<*>>()
+}
+
+internal fun getLocalDelegateReference(name: String, type: dynamic, mutable: Boolean, lambda: dynamic): KProperty<*> {
+    return getPropertyCallableRef(name, 0, type, lambda, if (mutable) lambda else null)
+}
+
+private fun getPropertyRefClass(obj: dynamic, metadata: dynamic): dynamic {
+    obj.`$metadata$` = metadata;
+    obj.constructor = obj;
+    return obj;
+}
+
+private fun getKPropMetadata(paramCount: Int, setter: Any?, type: dynamic): dynamic {
+    val mdata = propertyRefClassMetadataCache[paramCount][if (setter == null) 0 else 1]
+    if (mdata.interfaces.length == 0) {
+        mdata.interfaces.push(type)
+    }
+
+    return mdata
+}
+
+inline private fun metadataObject(): dynamic = js("{ kind: 'class', interfaces: [] }")
+
+private val propertyRefClassMetadataCache: Array<Array<dynamic>> = arrayOf<Array<dynamic>>(
+    //                 immutable     ,     mutable
+    arrayOf<dynamic>(metadataObject(), metadataObject()), // 0
+    arrayOf<dynamic>(metadataObject(), metadataObject()), // 1
+    arrayOf<dynamic>(metadataObject(), metadataObject())  // 2
+)
+