Bugfix: Make sure not to overwrite the empty optimized code map root.

test/mjsunit/regress/regress-568765.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --expose-gc --gc-interval=216
+// Flags: --nonative-context-specialization
+
+function PrettyPrint() { return ""; }
+function fail() { }
+assertSame = function assertSame() { if (found === expected) { if (1 / found) return; } else if ((expected !== expected) && (found !== found)) { return; }; }; assertEquals = function assertEquals(expected, found, name_opt) { if ( expected) { fail(PrettyPrint()); } };
+assertTrue = function assertTrue() { assertEquals(); };
+assertThrows = function assertThrows(code, type_opt, cause_opt) { var threwException = true; try { if (typeof code == 'function') { code(); } else {; } threwException = false; } catch (e) { if (typeof type_opt == 'function') {; } if (arguments.length >= 3) {; } return; } };
+assertInstanceof = function assertInstanceof() { if (obj instanceof type) { var actualTypeName = null; var actualConstructor = Object.getPrototypeOf().constructor; if (typeof actualConstructor == "function") {; }; } };
+function modifyPropertyOrValue() { var names; try {; } catch(e) {; return; } if(!names) return; name = names[rand_value % names.length]; if (isNaN()); }
+function nop() {}
+var __v_5 = {};
+var __v_12 = {};
+var __v_13 = {};
+var __v_16 = {};
+function __f_0() {
+}
+(function (){
+  function __f_6() {
+  }
+  a = __f_6();
+  b = __f_6();
+  name = "Array";
+})();
+(function (){
+  function __f_1() {
+    assertTrue();
+  }
+  __f_1();
+})();
+__v_10 = {
+}
+__v_11 = new Object();
+tailee1 = function() {
+  "use strict";
+  if (__v_12-- == 0) {
+  }
+  return nop();
+};
+%OptimizeFunctionOnNextCall(tailee1);
+assertEquals(__v_10, tailee1.call());
+__v_14 = 100000;
+gc();
+tailee2 = function() {
+  "use strict";
+  __v_14 = ((__v_14 | 0) - 1) | 0;
+  if ((__v_14 | 0) === 0) {
+  }
+};
+%OptimizeFunctionOnNextCall(tailee2);
+assertEquals(__v_11, tailee2.call());
+__v_13 = 999999;
+tailee3 = function() {
+  "use strict";
+  if (__v_13-- == 0) {
+  }
+};
+%OptimizeFunctionOnNextCall(tailee3);
+assertEquals(__v_9, tailee3.call(__v_11, __v_9));
+tailee4 = function(px) {
+  return nop(tailee4, this, px, undefined);
+};
+%OptimizeFunctionOnNextCall(tailee4);
+assertThrows(function() { tailee4.call(); });
+tailee5 = function() {
+  return nop();
+};
+%OptimizeFunctionOnNextCall(tailee5);
+assertThrows(function() { tailee5.call(); });
+tailee6 = function() {
+}
+tailee7 = function( py, pz, pa, pb, pc) {
+  return nop();
+};
+%OptimizeFunctionOnNextCall(tailee7);
+ tailee7.call();
+
+(function() {
+  Number.prototype[0] = "a";
+  Number.prototype[1] = "b";
+  Object.defineProperty(Number.prototype, 2, {
+    get: function() {
+    }
+  });
+  Number.prototype.length = 3;
+Array.prototype.includes.call(5);
+})();
+var __v_9 = -8;
+var __v_20 = 0;