Make formatting error message side-effect-free.

src/messages.js

 // Copyright 2012 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 149 matching lines @@
   var result = "";
   var arg_num = 0;
   for (var i = 0; i < format.length; i++) {
     var str = format[i];
     if (str.length == 2 && %_StringCharCodeAt(str, 0) == 0x25) {
       // Two-char string starts with "%".
       var arg_num = (%_StringCharCodeAt(str, 1) - 0x30) >>> 0;
       if (arg_num < 4) {
         // str is one of %0, %1, %2 or %3.
         try {
-          str = ToDetailString(args[arg_num]);
+          str = NoSideEffectToString(args[arg_num]);
         } catch (e) {
           if (%IsJSModule(args[arg_num]))
             str = "module";
           else if (IS_SPEC_OBJECT(args[arg_num]))
             str = "object";
           else
             str = "#<error>";
         }
       }
     }
     result += str;
   }
   return result;
 }
 
 
+function NoSideEffectToString(obj) {
+  if (IS_STRING(obj)) return obj;
+  if (IS_NUMBER(obj)) return %_NumberToString(obj);
+  if (IS_BOOLEAN(obj)) return x ? 'true' : 'false';
+  if (IS_UNDEFINED(obj)) return 'undefined';
+  if (IS_NULL(obj)) return 'null';
+  if (IS_OBJECT(obj) && %GetDataProperty(obj, "toString") === ObjectToString) {
+    var constructor = obj.constructor;
+    if (typeof constructor == "function") {
+      var constructorName = constructor.name;
+      if (IS_STRING(constructorName) && constructorName !== "") {
+        return "#<" + constructorName + ">";
+      }
+    }
+  }
+  if (IsNativeErrorObject(obj)) return %_CallFunction(obj, ErrorToString);
+  return %_CallFunction(obj, ObjectToString);
+}
+
+
 // To check if something is a native error we need to check the
 // concrete native error types. It is not sufficient to use instanceof
 // since it possible to create an object that has Error.prototype on
 // its prototype chain. This is the case for DOMException for example.
 function IsNativeErrorObject(obj) {
   switch (%_ClassOf(obj)) {
     case 'Error':
     case 'EvalError':
     case 'RangeError':
     case 'ReferenceError':
@@ skipping 1026 matching lines @@
     throw e;
   }
 }
 
 
 InstallFunctions($Error.prototype, DONT_ENUM, ['toString', ErrorToString]);
 
 // Boilerplate for exceptions for stack overflows. Used from
 // Isolate::StackOverflow().
 var kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);