Lock the prototype of internal classes.

src/math.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 177 matching lines @@
 
 // ECMA 262 - 15.8.2.18
 function MathTan(x) {
   if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
   return %Math_tan(x);
 }
 
 
 // -------------------------------------------------------------------
 
-function SetupMath() {
-  // Setup math constants.
+function SetUpMath() {
+  %CheckIsBootstrapping();
+  // Set up math constants.
   // ECMA-262, section 15.8.1.1.
   %OptimizeObjectForAddingMultipleProperties($Math, 8);
   %SetProperty($Math,
                "E",
                2.7182818284590452354,
                DONT_ENUM |  DONT_DELETE | READ_ONLY);
   // ECMA-262, section 15.8.1.2.
   %SetProperty($Math,
                "LN10",
                2.302585092994046,
@@ skipping 19 matching lines @@
   %SetProperty($Math,
                "SQRT1_2",
                0.7071067811865476,
                DONT_ENUM |  DONT_DELETE | READ_ONLY);
   %SetProperty($Math,
                "SQRT2",
                1.4142135623730951,
                DONT_ENUM |  DONT_DELETE | READ_ONLY);
   %ToFastProperties($Math);
 
-  // Setup non-enumerable functions of the Math object and
+  // Set up non-enumerable functions of the Math object and
   // set their names.
   InstallFunctionsOnHiddenPrototype($Math, DONT_ENUM, $Array(
     "random", MathRandom,
     "abs", MathAbs,
     "acos", MathAcos,
     "asin", MathAsin,
     "atan", MathAtan,
     "ceil", MathCeil,
     "cos", MathCos,
     "exp", MathExp,
     "floor", MathFloor,
     "log", MathLog,
     "round", MathRound,
     "sin", MathSin,
     "sqrt", MathSqrt,
     "tan", MathTan,
     "atan2", MathAtan2,
     "pow", MathPow,
     "max", MathMax,
     "min", MathMin
   ));
-};
+}
 
-
-SetupMath();
+SetUpMath();