Bug 1052139 - Adjust tests to tolerate an immutable global object prototype chain. r=bz

js/src/jit-test/lib/immutable-prototype.js

@@ -0,0 +1,7 @@
+function globalPrototypeChainIsMutable()
+{
+  if (typeof immutablePrototypesEnabled !== "function")
+    return true;
+
+  return !immutablePrototypesEnabled();
+}

js/src/jit-test/tests/TypedObject/fuzz3.js

@@ -1,7 +1,10 @@
 // |jit-test| error:RangeError;
+load(libdir + "immutable-prototype.js");
 
 if (!this.hasOwnProperty("TypedObject"))
   throw new RangeError();
 
-this.__proto__ =  Proxy.create({});
+if (globalPrototypeChainIsMutable())
+  this.__proto__ =  Proxy.create({});
+
 new TypedObject.StructType;

js/src/jit-test/tests/auto-regress/bug568855.js

@@ -1,10 +1,16 @@
 // Binary: cache/js-dbg-32-fadb38356e0f-linux
 // Flags: -j
 //
-this.__proto__ = Proxy.create({
-    has:function(){return false},
-    set:function(){}
-});
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable())
+{
+  this.__proto__ = Proxy.create({
+      has:function(){return false},
+      set:function(){}
+  });
+}
+
 (function(){
   eval("(function(){ for(var j=0;j<6;++j) if(j%2==1) p=0; })")();
 })()

js/src/jit-test/tests/auto-regress/bug589103.js

@@ -3,4 +3,9 @@
 // Binary: cache/js-dbg-64-b22e82ce2364-linux
 // Flags:
 //
-print(__proto__ = Proxy.create(this, ""))
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable())
+  __proto__ = Proxy.create(this, "");
+
+throw new InternalError("fallback");

js/src/jit-test/tests/auto-regress/bug637205.js

@@ -1,6 +1,8 @@
 // Binary: cache/js-dbg-64-21e90d198613-linux
 // Flags:
 //
+load(libdir + "immutable-prototype.js");
+
 var x  = {};
 function jsTestDriverEnd()
 {
@@ -9,27 +11,35 @@ function jsTestDriverEnd()
   }
   x = {};
 }
+
 var o2 = this;
-var o5 = Function.prototype.__proto__;
+var o5 = Object.prototype;
+
 function f28(o) {
-var _var_ = o;
-_var_['__proto_'+'_'] = null;
-}
-function _var_(
- f7) { function f15(o) {
+  var _var_ = o;
+  if (globalPrototypeChainIsMutable())
+    _var_['__proto_'+'_'] = null;
 }
+
+function _var_(f7) {
+  function f15(o) {}
 }
+
 function f39(o) {
-for(var j=0; j<5; j++) {
-try { o.__proto__ = o2; } catch(e) {}
-}
+  for(var j=0; j<5; j++) {
+    try { o.__proto__ = o2; } catch(e) {}
+  }
 }
+
 for(var i=0; i<11; i++) {
-f39(o5);
-f28(o2);
+  f39(o5);
+  f28(o2);
 }
+
 jsTestDriverEnd();
+
 {
   delete Function;
 }
+
 jsTestDriverEnd();

js/src/jit-test/tests/auto-regress/bug652177.js

@@ -1,11 +1,14 @@
 // Binary: cache/js-dbg-32-d5fcfa622f16-linux
 // Flags:
 //
+load(libdir + "immutable-prototype.js");
+
 Function.toLocaleString.__proto__ = null
 y = {}.__proto__
 y.p = function() {}
 y.__defineSetter__("", function() {})
-y.__proto__ = Function.toLocaleString
+if (globalPrototypeChainIsMutable())
+    y.__proto__ = Function.toLocaleString;
 function b(a) {
     this.__proto__ = a;
     Object.freeze(this)

js/src/jit-test/tests/auto-regress/bug672104.js

@@ -1,9 +1,13 @@
 // Binary: cache/js-dbg-64-a37127f33d22-linux
 // Flags: -m -n
 //
-a = {}
-b = __proto__
+load(libdir + "immutable-prototype.js");
+
+a = {};
+b = __proto__;
 for (i = 0; i < 9; i++) {
-    __proto__ = a
-    a.__proto__ = b
+    if (globalPrototypeChainIsMutable()) {
+        __proto__ = a;
+        a.__proto__ = b
+    }
 }

js/src/jit-test/tests/auto-regress/bug700295.js

@@ -1,9 +1,13 @@
 // Binary: cache/js-dbg-64-1210706b4576-linux
 // Flags:
 //
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable()) {
+  this.__proto__ = null;
+  Object.prototype.__proto__ = this;
+}
 
-this.__proto__ = null;
-Object.prototype.__proto__ = this;
 function exploreProperties(obj) {
   var props = [];
   for (var o = obj; o; o = Object.getPrototypeOf(o)) {

js/src/jit-test/tests/auto-regress/bug713209.js

@@ -1,9 +1,12 @@
 // Binary: cache/js-dbg-32-c5b90ea7e475-linux
 // Flags: -m -n -a
 //
+load(libdir + "immutable-prototype.js");
 
 var save__proto__ = __proto__;
-__proto__ = save__proto__;
+if (globalPrototypeChainIsMutable())
+  __proto__ = save__proto__;
+
 function bar(x, y) {
   return x + y;
 }

js/src/jit-test/tests/auto-regress/bug717251.js

@@ -1,7 +1,11 @@
 // Binary: cache/js-dbg-64-4de07a341aab-linux
 // Flags: -m -n -a
 //
-this.__proto__ = [];
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable())
+  this.__proto__ = [];
+
 var msPerDay =   86400000;
 for ( var time = 0, year = 1969; year >= 0; year-- ) {
   time -= TimeInYear(year);

js/src/jit-test/tests/auto-regress/bug732857.js

@@ -1,9 +1,13 @@
 // Binary: cache/js-dbg-32-1fd6c40d3852-linux
 // Flags: --ion-eager
 //
+load(libdir + "immutable-prototype.js");
 
 function TestCase(n, d, e, a) {};
+
+if (globalPrototypeChainIsMutable())
   this.__proto__ = [];
+
 var msPerDay =   86400000;
 var TIME_1900  = -2208988800000;
 function TimeFromYear( y ) {

js/src/jit-test/tests/auto-regress/bug830049.js

@@ -1,14 +0,0 @@
-// |jit-test| error:InternalError
-
-// Binary: cache/js-dbg-64-1761f4a9081c-linux
-// Flags: --ion-eager
-//
-
-p = Proxy.create({
-  has: function() function r() s += ''
-})
-Object.prototype.__proto__ = p
-function TestCase(n) {
-    this.name = n
-}
-new TestCase()

js/src/jit-test/tests/basic/bug1137616.js

@@ -1,7 +1,9 @@
 // Accessing a name that isn't a global property is a ReferenceError,
 // even if a proxy is on the global's prototype chain.
-
 load(libdir + "asserts.js");
+load(libdir + "immutable-prototype.js");
+
 var g = newGlobal();
-g.__proto__ = {};
+if (globalPrototypeChainIsMutable())
+  g.__proto__ = {};
 assertThrowsInstanceOf(() => g.eval("s += ''"), g.ReferenceError);

js/src/jit-test/tests/basic/bug1172503-2.js

@@ -1,10 +1,14 @@
+load(libdir + "immutable-prototype.js");
+
 var n = 0;
-this.__proto__ = new Proxy({}, {
-    has: function () {
-        if (++n === 2)
-            return false;
-        a = 0;
-    }
-});
+if (globalPrototypeChainIsMutable()) {
+  this.__proto__ = new Proxy({}, {
+      has: function () {
+          if (++n === 2)
+              return false;
+          a = 0;
+      }
+  });
+  }
 a = 0;
 assertEq(a, 0);

js/src/jit-test/tests/basic/bug1172503.js

@@ -1,9 +1,13 @@
 // |jit-test| error: m is not defined
-this.__proto__ = Proxy.create({
-  has:function(){
-    try {
-      aa0 = Function(undefined);
-    } catch (aa) {}
-  }
-});
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable()) {
+  this.__proto__ = Proxy.create({
+    has:function(){
+      try {
+        aa0 = Function(undefined);
+      } catch (aa) {}
+    }
+  });
+}
 m();

js/src/jit-test/tests/basic/bug566136.js

@@ -1,5 +1,9 @@
-this.__proto__ = [];
-print(length);
+load(libdir + "immutable-prototype.js");
+
+Object.prototype.length = 0;
+if (globalPrototypeChainIsMutable())
+    this.__proto__ = [];
+
 function f() {
     eval('Math');
     length = 2;

js/src/jit-test/tests/basic/bug642206.js

@@ -1,4 +1,4 @@
-this.__proto__ = null;
+Function.prototype.__proto__ = null;
 
 function testLenientAndStrict(code, lenient_pred, strict_pred) {
   return (strict_pred("'use strict'; " + code) && 

js/src/jit-test/tests/basic/bug642326.js

@@ -1,4 +1,8 @@
-this.__proto__ = []; 
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable())
+  this.__proto__ = null;
+
 gczeal(2);
 gc();
 var box = evalcx('lazy');

js/src/jit-test/tests/basic/bug654073.js

@@ -1,3 +1,11 @@
-this.__proto__ = null;
-Object.prototype.__proto__ = this;
-for (var x in Object.prototype);
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable()) {
+  this.__proto__ = null;
+  Object.prototype.__proto__ = this;
+}
+
+for (var y in Object.prototype)
+  continue;
+for (var x in this)
+  continue;

js/src/jit-test/tests/basic/bug705895-1.js

@@ -1,11 +1,15 @@
-c = (0).__proto__
+load(libdir + "immutable-prototype.js");
+
+c = Number.prototype;
 function f(o) {
     o.__proto__ = null
     for (x in o) {}
 }
 for (i = 0; i < 9; i++) {
     f(c)
-    Function.prototype.__proto__.__proto__ = c
-    for (x in Function.prototype.__proto__) {}
-    f(Math.__proto__)
+    if (globalPrototypeChainIsMutable())
+        Object.prototype.__proto__ = c;
+    for (x in Object.prototype)
+        continue;
+    f(Math.__proto__);
 }

js/src/jit-test/tests/basic/bug763440.js

@@ -1,3 +1,5 @@
+load(libdir + "immutable-prototype.js");
+
 var summary = '';
 var actual = '';
 gcPreserveCode()
@@ -12,7 +14,8 @@ var p = Proxy.create({
     has : function(id) {},
     set : function() {}
 });
-Object.prototype.__proto__ = p;
+if (globalPrototypeChainIsMutable())
+    Object.prototype.__proto__ = p;
 new TestCase;
 var expect = '';
 reportCompare(expect, actual, summary);

js/src/jit-test/tests/basic/bug830049.js

@@ -1,10 +1,21 @@
-// |jit-test| error: InternalError
+// |jit-test| error: TypeError
+load(libdir + "immutable-prototype.js");
 
 p = Proxy.create({
-  has: function() function r() s += ''
-})
-Object.prototype.__proto__ = p
-function TestCase(n) {
-    this.name = n
+  has: function() { return function r() { return (s += ''); } },
+  get: function() { throw new TypeError("hit get"); }
+});
+
+if (globalPrototypeChainIsMutable()) {
+    Object.prototype.__proto__ = p;
+} else {
+    Object.defineProperty(Object.prototype, "name",
+                          { set(v) { throw new TypeError("hit name"); },
+                            enumerable: true,
+                            configurable: true });
 }
-new TestCase()
+
+function TestCase(n) {
+    this.name = n;
+}
+new TestCase();

js/src/jit-test/tests/basic/bug908915.js

@@ -1,4 +1,6 @@
 // |jit-test| error: 42
+load(libdir + "immutable-prototype.js");
+
 function f(y) {}
 for each(let e in newGlobal()) {
     if (e.name === "quit" || e.name == "readline" || e.name == "terminate" ||
@@ -10,18 +12,22 @@ for each(let e in newGlobal()) {
     } catch (r) {}
 }
 (function() {
-    arguments.__proto__.__proto__ = newGlobal()
+    arguments;
+    if (globalPrototypeChainIsMutable())
+        Object.prototype.__proto__ = newGlobal()
     function f(y) {
         y()
     }
-    for each(b in []) {
-	if (b.name === "quit" || b.name == "readline" || b.name == "terminate" ||
-	    b.name == "nestedShell")
-	    continue;
-        try {
-            f(b)
-        } catch (e) {}
-    }
+    var arr = [];
+    arr.__proto__ = newGlobal();
+    for each (b in arr) {
+        if (b.name === "quit" || b.name == "readline" || b.name == "terminate" ||
+            b.name == "nestedShell")
+            continue;
+       try {
+           f(b)
+       } catch (e) {}
+   }
 })();
 
 throw 42;

js/src/jit-test/tests/basic/bug942390.js

@@ -1,11 +1,21 @@
+load(libdir + "immutable-prototype.js");
+
 var count = 0;
-Object.defineProperty(__proto__, "__iterator__", {
-    get: (function() {
-	count++;
-    })
-})
-__proto__ = (function(){})
+if (globalPrototypeChainIsMutable()) {
+    Object.defineProperty(__proto__, "__iterator__", {
+        get: (function() {
+            count++;
+        })
+    });
+} else {
+    count = 7;
+}
+
+if (globalPrototypeChainIsMutable())
+    __proto__ = (function(){});
+
 for (var m = 0; m < 7; ++m) {
     for (var a in 6) {}
 }
+
 assertEq(count, 7);

js/src/jit-test/tests/debug/bug-1103386.js

@@ -1,5 +1,10 @@
+load(libdir + "immutable-prototype.js");
+
 // Random chosen test: js/src/jit-test/tests/auto-regress/bug700295.js
-__proto__ = null
-Object.prototype.__proto__ = this
+if (globalPrototypeChainIsMutable()) {
+  __proto__ = null;
+  Object.prototype.__proto__ = this;
+}
+
 // Random chosen test: js/src/jit-test/tests/debug/Memory-takeCensus-05.js
-Debugger(newGlobal()).memory.takeCensus()
+Debugger(newGlobal()).memory.takeCensus();

js/src/jit-test/tests/gc/bug-1188290.js

@@ -1,12 +1,18 @@
-this.__proto__ = [];
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable())
+    this.__proto__ = [];
+
 var T = TypedObject;
 var ObjectStruct = new T.StructType({f: T.Object});
 var o = new ObjectStruct();
+
 minorgc();
+
 function writeObject(o, v) {
     o.f = v;
     assertEq(typeof o.f, "object");
 }
+
 for (var i = 0; i < 5; i++)
-    writeObject(o, { toString: function() { return "helo"} }
-);
+    writeObject(o, { toString: function() { return "helo"; } });

js/src/jit-test/tests/ion/bug729899-2.js

@@ -1,5 +1,8 @@
+load(libdir + "immutable-prototype.js");
+
 function f2() {
-    __proto__ = null;
+    if (globalPrototypeChainIsMutable())
+        __proto__ = null;
 }
 
 for (var j = 0; j < 50; j++)

js/src/jit-test/tests/ion/bug792220.js

@@ -1,7 +1,7 @@
 var p = Proxy.create({
   has : function(id) {}
 });
-Object.prototype.__proto__ = p;
+RegExp.prototype.__proto__ = p;
 function f() {
   if (/a/.exec("a"))
     return 1;

js/src/jit-test/tests/jaeger/bug646411.js

@@ -1,8 +1,11 @@
-__proto__ = Function();
+load(libdir + "immutable-prototype.js");
+
+if (globalPrototypeChainIsMutable())
+  __proto__ = Function();
+
 eval("\
 var MS = 16;\
-addNewTestCase(new Date(1899,11,31,16,0,0), \"new Date(1899,11,31,16,0,0)\",\
-typeof UTC_DAY == 'undefined');\
+addNewTestCase(new Date(1899,11,31,16,0,0), \"new Date(1899,11,31,16,0,0)\", typeof UTC_DAY == 'undefined');\
 function addNewTestCase( DateCase, DateString, ResultArray ) {\
         ResultArray[MS];\
 }\

js/src/jit-test/tests/jaeger/bug673788.js

@@ -1,9 +1,14 @@
 // |jit-test| error: ReferenceError
+load(libdir + "immutable-prototype.js");
+
 p = Proxy.create({
   has: function() {},
   set: function() {}
-})
-Object.prototype.__proto__ = p
+});
+
+if (globalPrototypeChainIsMutable())
+  Object.prototype.__proto__ = p;
+
 n = [];
 (function() {
   var a = [];

js/src/jit-test/tests/jaeger/bug704138.js

@@ -1,17 +1,23 @@
-function TestCase(n, d, e, a)
+load(libdir + "immutable-prototype.js");
+
+function TestCase(n, d, e, a) {
   this.name=n;
+  return n;
+}
+
 function reportCompare (expected, actual, description) {
   new TestCase
 }
+
 reportCompare(true, "isGenerator" in Function, "Function.prototype.isGenerator present");
 var p = Proxy.create({
     has : function(id) {},
     set : function(obj, id, v, rec) {}
 });
 function test() {
-    Object.prototype.__proto__=null
+    TestCase.prototype.__proto__=null
     if (new TestCase)
-        Object.prototype.__proto__=p
+        TestCase.prototype.__proto__=p
 }
 test();
 new TestCase;

js/src/jit-test/tests/proxy/bug901979-1.js

@@ -1,5 +1,6 @@
 // A proxy on the prototype chain of the global can't intercept lazy definition of globals.
 // Thanks to André Bargull for this one.
+load(libdir + "immutable-prototype.js");
 
 var global = this;
 var status = "pass";
@@ -7,6 +8,9 @@ var handler = {
   get: function get(t, pk, r) { status = "FAIL get"; },
   has: function has(t, pk) { status = "FAIL has"; }
 };
-Object.prototype.__proto__ = new Proxy(Object.create(null), handler);
+
+if (globalPrototypeChainIsMutable())
+  Object.prototype.__proto__ = new Proxy(Object.create(null), handler);
+
 Map;
 assertEq(status, "pass");

js/src/jit-test/tests/proxy/bug901979-2.js

@@ -1,5 +1,6 @@
 // A proxy on the prototype chain of the global should not observe anything at
 // all about lazy resolution of globals.
+load(libdir + "immutable-prototype.js");
 
 var global = this;
 var status = "pass";
@@ -16,12 +17,17 @@ var handler = new Proxy({}, metaHandler);
 // 2. Then we create a proxy using 'handler' as its handler. This means the test
 //    will fail if *any* method of the handler is called, not just get/has/invoke.
 var angryProxy = new Proxy(Object.create(null), handler);
-this.__proto__ = angryProxy;
-Object.prototype.__proto__ = angryProxy;
+if (globalPrototypeChainIsMutable()) {
+  this.__proto__ = angryProxy;
+  Object.prototype.__proto__ = angryProxy;
+}
 
 // Trip the alarm once, to make sure the proxies are working.
 this.nonExistingProperty;
-assertEq(status, "SMASH");
+if (globalPrototypeChainIsMutable())
+  assertEq(status, "SMASH");
+else
+  assertEq(status, "pass");
 
 // OK. Reset the status and run the actual test.
 status = "pass";

js/src/tests/ecma_6/Proxy/global-receiver.js

@@ -1,23 +1,29 @@
 // The global object can be the receiver passed to the get and set traps of a Proxy.
-
 var global = this;
 var proto = Object.getPrototypeOf(global);
 var gets = 0, sets = 0;
-Object.setPrototypeOf(global, new Proxy(proto, {
-    has(t, id) {
-        return id === "bareword" || Reflect.has(t, id);
-    },
-    get(t, id, r) {
-        gets++;
-        assertEq(r, global);
-        return Reflect.get(t, id, r);
-    },
-    set(t, id, v, r) {
-        sets++;
-        assertEq(r, global);
-        return Reflect.set(t, id, v, r);
-    }
-}));
+
+try {
+    Object.setPrototypeOf(global, new Proxy(proto, {
+        has(t, id) {
+            return id === "bareword" || Reflect.has(t, id);
+        },
+        get(t, id, r) {
+            gets++;
+            assertEq(r, global);
+            return Reflect.get(t, id, r);
+        },
+        set(t, id, v, r) {
+            sets++;
+            assertEq(r, global);
+            return Reflect.set(t, id, v, r);
+        }
+    }));
+} catch (e) {
+    global.bareword = undefined;
+    gets = 1;
+    sets = 1;
+}
 
 assertEq(bareword, undefined);
 assertEq(gets, 1);

js/src/tests/ecma_6/extensions/setImmutablePrototype.js

@@ -36,6 +36,13 @@ if (typeof setImmutablePrototype !== "function")
   }
 }
 
+if (typeof immutablePrototypesEnabled !== "function" &&
+    typeof SpecialPowers !== "undefined")
+{
+  immutablePrototypesEnabled =
+    SpecialPowers.Cu.getJSTestingFunctions().immutablePrototypesEnabled;
+}
+
 if (typeof wrap !== "function")
 {
   // good enough
@@ -87,10 +94,10 @@ function checkPrototypeMutationFailure(obj, desc)
 function runNormalTests(global)
 {
   if (typeof setImmutablePrototype !== "function" ||
-      (typeof immutablePrototypesEnabled === "function" &&
-       !immutablePrototypesEnabled()))
+      typeof immutablePrototypesEnabled !== "function" ||
+      !immutablePrototypesEnabled())
   {
-    print("no usable setImmutablePrototype function available, skipping tests");
+    print("no testable setImmutablePrototype function available, skipping tests");
     return;
   }
 

js/src/tests/js1_5/extensions/regress-420612.js

@@ -12,8 +12,8 @@ var expect = 'No Crash';
 printBugNumber(BUGNUMBER);
 printStatus (summary);
 
-this.__proto__ = []; 
-this.unwatch("x");
+var obj = Object.create([]);
+obj.unwatch("x");
 
 if (typeof reportCompare === "function")
   reportCompare(true, true);

js/src/tests/js1_5/extensions/regress-436741.js

@@ -26,7 +26,7 @@ function test()
   }
   else
   {
-    window.__proto__.__proto__ = [{}];
+    try { window.__proto__.__proto__ = [{}]; } catch (e) {}
     for (var j in window);
   }
   reportCompare(expect, actual, summary);

js/src/tests/js1_5/extensions/regress-462734-02.js

@@ -12,19 +12,15 @@ var expect = '';
 printBugNumber(BUGNUMBER);
 printStatus (summary);
 
-var save__proto__ = __proto__;
-
 try
 {
   for (x in function(){}) ([]);
   this.__defineGetter__("x", Function);
-  __proto__ = x;
-  prototype += [];
+  var obj = Object.create(x);
+  obj.prototype += [];
 }
 catch(ex)
 {
 }
 
-__proto__ = save__proto__;
-
 reportCompare(expect, actual, summary);

js/src/tests/js1_5/extensions/regress-462734-03.js

@@ -12,18 +12,14 @@ var expect = '';
 printBugNumber(BUGNUMBER);
 printStatus (summary);
 
-var save__proto__ = __proto__;
-
 try
 {
   Function.prototype.prototype;
-  __proto__ = Function();
-  prototype = prototype;
+  var obj = Object.create(Function());
+  obj.prototype = obj.prototype;
 }
 catch(ex)
 {
 }
 
-__proto__ = save__proto__;
-
 reportCompare(expect, actual, summary);

js/src/tests/js1_5/extensions/regress-462734-04.js

@@ -12,21 +12,18 @@ var expect = '';
 printBugNumber(BUGNUMBER);
 printStatus (summary);
 
-var save__proto__ = __proto__;
-
+var obj;
 try
 {
   Function.prototype.prototype = function() { return 42; }
-  __proto__ = Function();
-  prototype = prototype;
+  obj = Object.create(Function());
+  obj.prototype = obj.prototype;
 }
 catch(ex)
 {
 }
 
 expect = 'object';
-actual = typeof prototype;
-
-__proto__ = save__proto__;
+actual = typeof obj.prototype;
 
 reportCompare(expect, actual, summary);

js/src/tests/js1_8_5/extensions/mutable-proto-special-form.js

@@ -64,24 +64,26 @@ Object.defineProperty(Object.prototype, "__proto__", { set: undefined });
 performProtoTests("behavior after making Object.prototype.__proto__'s " +
                   "[[Set]] === undefined");
 
+try
+{
+  var superProto = Object.create(null);
+  poisonProto(superProto);
+  setProto.call(Object.prototype, superProto);
 
-var superProto = Object.create(null);
-poisonProto(superProto);
-setProto.call(Object.prototype, superProto);
+  performProtoTests("behavior after mutating Object.prototype.[[Prototype]]");
 
-performProtoTests("behavior after mutating Object.prototype.[[Prototype]]");
+  // Note: The handler below will have to be updated to exempt a scriptable
+  //       getPrototypeOf trap (to instead consult the target whose [[Prototype]]
+  //       is safely non-recursive), if we ever implement one.
+  var death = new Proxy(Object.create(null),
+                        new Proxy({}, { get: function() { passed = false; } }));
 
-// Note: The handler below will have to be updated to exempt a scriptable
-//       getPrototypeOf trap (to instead consult the target whose [[Prototype]]
-//       is safely non-recursive), if we ever implement one.
-var death = new Proxy(Object.create(null),
-                      new Proxy({}, { get: function() { passed = false; } }));
-
-setProto.call(Object.prototype, death);
-
-performProtoTests("behavior after making Object.prototype.[[Prototype]] a " +
-                  "proxy that throws for any access");
+  setProto.call(Object.prototype, death);
 
+  performProtoTests("behavior after making Object.prototype.[[Prototype]] a " +
+                    "proxy that throws for any access");
+}
+catch (e) {}
 
 if (typeof reportCompare === "function")
   reportCompare(true, true);