[Wasm] Major compiler and stdlib update

libraries/stdlib/wasm/builtins/kotlin/String.kt

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2010-2019 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
+
+import kotlin.wasm.internal.*
+
+/**
+ * The `String` class represents character strings. All string literals in Kotlin programs, such as `"abc"`, are
+ * implemented as instances of this class.
+ */
+@WasmPrimitive
+public class String constructor(public val string: String) : Comparable<String>, CharSequence {
+    public companion object;
+
+    /**
+     * Returns a string obtained by concatenating this string with the string representation of the given [other] object.
+     */
+    public operator fun plus(other: Any?): String =
+        stringPlusImpl(this, other.toString())
+
+    public override val length: Int
+        get() = stringLengthImpl(this)
+
+    /**
+     * Returns the character of this string at the specified [index].
+     *
+     * If the [index] is out of bounds of this string, throws an [IndexOutOfBoundsException] except in Kotlin/JS
+     * where the behavior is unspecified.
+     */
+    public override fun get(index: Int): Char =
+        stringGetCharImpl(this, index)
+
+    public override fun subSequence(startIndex: Int, endIndex: Int): CharSequence =
+        stringSubSequenceImpl(this, startIndex, endIndex)
+
+    public override fun compareTo(other: String): Int =
+        stringCompareToImpl(this, other)
+
+    public override fun equals(other: Any?): Boolean {
+        if (other is String)
+            return this.compareTo(other) == 0
+        return false
+    }
+
+    public override fun toString(): String = this
+
+    // TODO: Implement
+    public override fun hashCode(): Int = 10
+}
+
+@WasmImport("runtime", "String_plus")
+private fun stringPlusImpl(it: String, other: String): String =
+    implementedAsIntrinsic
+
+@WasmImport("runtime", "String_getLength")
+private fun stringLengthImpl(it: String): Int =
+    implementedAsIntrinsic
+
+@WasmImport("runtime", "String_getChar")
+private fun stringGetCharImpl(it: String, index: Int): Char =
+    implementedAsIntrinsic
+
+@WasmImport("runtime", "String_compareTo")
+private fun stringCompareToImpl(it: String, other: String): Int =
+    implementedAsIntrinsic
+
+@WasmImport("runtime", "String_subsequence")
+private fun stringSubSequenceImpl(string: String, startIndex: Int, endIndex: Int): String =
+    implementedAsIntrinsic