text: // 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
  //       with the distribution.
  //     * Neither the name of Google Inc. nor the names of its
  //       contributors may be used to endorse or promote products derived
  //       from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  // -------------------------------------------------------------------
  //
  // If this object gets passed to an error constructor the error will
  // get an accessor for .message that constructs a descriptive error
  // message on access.
  var kAddMessageAccessorsMarker = { };
  
  // This will be lazily initialized when first needed (and forcibly
  // overwritten even though it's const).
  var kMessages = 0;
  
  function FormatString(format, message) {
    var args = %MessageGetArguments(message);
    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]);
          } catch (e) {
            str = "#<error>";
          }
        }
      }
      result += str;
    }
    return result;
  }
  
  
  // 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':
      case 'SyntaxError':
      case 'TypeError':
      case 'URIError':
        return true;
    }
    return false;
  }
  
  
  // When formatting internally created error messages, do not
  // invoke overwritten error toString methods but explicitly use
  // the error to string method. This is to avoid leaking error
  // objects between script tags in a browser setting.
  function ToStringCheckErrorObject(obj) {
    if (IsNativeErrorObject(obj)) {
      return %_CallFunction(obj, ErrorToString);
    } else {
      return ToString(obj);
    }
  }
  
  
  function ToDetailString(obj) {
    if (obj != null && IS_OBJECT(obj) && obj.toString === ObjectToString) {
      var constructor = obj.constructor;
      if (typeof constructor == "function") {
        var constructorName = constructor.name;
        if (IS_STRING(constructorName) && constructorName !== "") {
          return "#<" + constructorName + ">";
        }
      }
    }
    return ToStringCheckErrorObject(obj);
  }
  
  
  function MakeGenericError(constructor, type, args) {
    if (IS_UNDEFINED(args)) {
      args = [];
    }
    var e = new constructor(kAddMessageAccessorsMarker);
    e.type = type;
    e.arguments = args;
    return e;
  }
  
  
  /**
   * Set up the Script function and constructor.
   */
  %FunctionSetInstanceClassName(Script, 'Script');
  %SetProperty(Script.prototype, 'constructor', Script,
               DONT_ENUM | DONT_DELETE | READ_ONLY);
  %SetCode(Script, function(x) {
    // Script objects can only be created by the VM.
    throw new $Error("Not supported");
  });
  
  
  // Helper functions; called from the runtime system.
  function FormatMessage(message) {
    if (kMessages === 0) {
      var messagesDictionary = [
        // Error
        "cyclic_proto",                 ["Cyclic __proto__ value"],
        "code_gen_from_strings",        ["Code generation from strings disallowed for this context"],
        // TypeError
        "unexpected_token",             ["Unexpected token ", "%0"],
        "unexpected_token_number",      ["Unexpected number"],
        "unexpected_token_string",      ["Unexpected string"],
        "unexpected_token_identifier",  ["Unexpected identifier"],
        "unexpected_reserved",          ["Unexpected reserved word"],
        "unexpected_strict_reserved",   ["Unexpected strict mode reserved word"],
        "unexpected_eos",               ["Unexpected end of input"],
        "malformed_regexp",             ["Invalid regular expression: /", "%0", "/: ", "%1"],
        "unterminated_regexp",          ["Invalid regular expression: missing /"],
        "regexp_flags",                 ["Cannot supply flags when constructing one RegExp from another"],
        "incompatible_method_receiver", ["Method ", "%0", " called on incompatible receiver ", "%1"],
        "invalid_lhs_in_assignment",    ["Invalid left-hand side in assignment"],
        "invalid_lhs_in_for_in",        ["Invalid left-hand side in for-in"],
        "invalid_lhs_in_postfix_op",    ["Invalid left-hand side expression in postfix operation"],
        "invalid_lhs_in_prefix_op",     ["Invalid left-hand side expression in prefix operation"],
        "multiple_defaults_in_switch",  ["More than one default clause in switch statement"],
        "newline_after_throw",          ["Illegal newline after throw"],
        "redeclaration",                ["%0", " '", "%1", "' has already been declared"],
        "no_catch_or_finally",          ["Missing catch or finally after try"],
        "unknown_label",                ["Undefined label '", "%0", "'"],
        "uncaught_exception",           ["Uncaught ", "%0"],
        "stack_trace",                  ["Stack Trace:\n", "%0"],
        "called_non_callable",          ["%0", " is not a function"],
        "undefined_method",             ["Object ", "%1", " has no method '", "%0", "'"],
        "property_not_function",        ["Property '", "%0", "' of object ", "%1", " is not a function"],
        "cannot_convert_to_primitive",  ["Cannot convert object to primitive value"],
        "not_constructor",              ["%0", " is not a constructor"],
        "not_defined",                  ["%0", " is not defined"],
        "non_object_property_load",     ["Cannot read property '", "%0", "' of ", "%1"],
        "non_object_property_store",    ["Cannot set property '", "%0", "' of ", "%1"],
        "non_object_property_call",     ["Cannot call method '", "%0", "' of ", "%1"],
        "with_expression",              ["%0", " has no properties"],
        "illegal_invocation",           ["Illegal invocation"],
        "no_setter_in_callback",        ["Cannot set property ", "%0", " of ", "%1", " which has only a getter"],
        "apply_non_function",           ["Function.prototype.apply was called on ", "%0", ", which is a ", "%1", " and not a function"],
        "apply_wrong_args",             ["Function.prototype.apply: Arguments list has wrong type"],
        "invalid_in_operator_use",      ["Cannot use 'in' operator to search for '", "%0", "' in ", "%1"],
        "instanceof_function_expected", ["Expecting a function in instanceof check, but got ", "%0"],
        "instanceof_nonobject_proto",   ["Function has non-object prototype '", "%0", "' in instanceof check"],
        "null_to_object",               ["Cannot convert null to object"],
        "reduce_no_initial",            ["Reduce of empty array with no initial value"],
        "getter_must_be_callable",      ["Getter must be a function: ", "%0"],
        "setter_must_be_callable",      ["Setter must be a function: ", "%0"],
        "value_and_accessor",           ["Invalid property.  A property cannot both have accessors and be writable or have a value, ", "%0"],
        "proto_object_or_null",         ["Object prototype may only be an Object or null"],
        "property_desc_object",         ["Property description must be an object: ", "%0"],
        "redefine_disallowed",          ["Cannot redefine property: ", "%0"],
        "define_disallowed",            ["Cannot define property:", "%0", ", object is not extensible."],
        "non_extensible_proto",         ["%0", " is not extensible"],
        "handler_non_object",           ["Proxy.", "%0", " called with non-object as handler"],
        "proto_non_object",             ["Proxy.", "%0", " called with non-object as prototype"],
        "trap_function_expected",       ["Proxy.", "%0", " called with non-function for '", "%1", "' trap"],
        "handler_trap_missing",         ["Proxy handler ", "%0", " has no '", "%1", "' trap"],
        "handler_trap_must_be_callable", ["Proxy handler ", "%0", " has non-callable '", "%1", "' trap"],
        "handler_returned_false",       ["Proxy handler ", "%0", " returned false from '", "%1", "' trap"],
        "handler_returned_undefined",   ["Proxy handler ", "%0", " returned undefined from '", "%1", "' trap"],
        "proxy_prop_not_configurable",  ["Proxy handler ", "%0", " returned non-configurable descriptor for property '", "%2", "' from '", "%1", "' trap"],
        "proxy_non_object_prop_names",  ["Trap '", "%1", "' returned non-object ", "%0"],
        "proxy_repeated_prop_name",     ["Trap '", "%1", "' returned repeated property name '", "%2", "'"],
        "invalid_weakmap_key",          ["Invalid value used as weak map key"],
        // RangeError
        "invalid_array_length",         ["Invalid array length"],
        "stack_overflow",               ["Maximum call stack size exceeded"],
        "invalid_time_value",           ["Invalid time value"],
        // SyntaxError
        "unable_to_parse",              ["Parse error"],
        "invalid_regexp_flags",         ["Invalid flags supplied to RegExp constructor '", "%0", "'"],
        "invalid_regexp",               ["Invalid RegExp pattern /", "%0", "/"],
        "illegal_break",                ["Illegal break statement"],
        "illegal_continue",             ["Illegal continue statement"],
        "illegal_return",               ["Illegal return statement"],
        "illegal_let",                  ["Illegal let declaration outside extended mode"],
        "error_loading_debugger",       ["Error loading debugger"],
        "no_input_to_regexp",           ["No input to ", "%0"],
        "invalid_json",                 ["String '", "%0", "' is not valid JSON"],
        "circular_structure",           ["Converting circular structure to JSON"],
        "called_on_non_object",         ["%0", " called on non-object"],
        "called_on_null_or_undefined",  ["%0", " called on null or undefined"],
        "array_indexof_not_defined",    ["Array.getIndexOf: Argument undefined"],
        "object_not_extensible",        ["Can't add property ", "%0", ", object is not extensible"],
        "illegal_access",               ["Illegal access"],
        "invalid_preparser_data",       ["Invalid preparser data for function ", "%0"],
        "strict_mode_with",             ["Strict mode code may not include a with statement"],
        "strict_catch_variable",        ["Catch variable may not be eval or arguments in strict mode"],
        "too_many_arguments",           ["Too many arguments in function call (only 32766 allowed)"],
        "too_many_parameters",          ["Too many parameters in function definition (only 32766 allowed)"],
        "too_many_variables",           ["Too many variables declared (only 32767 allowed)"],
        "strict_param_name",            ["Parameter name eval or arguments is not allowed in strict mode"],
        "strict_param_dupe",            ["Strict mode function may not have duplicate parameter names"],
        "strict_var_name",              ["Variable name may not be eval or arguments in strict mode"],
        "strict_function_name",         ["Function name may not be eval or arguments in strict mode"],
        "strict_octal_literal",         ["Octal literals are not allowed in strict mode."],
        "strict_duplicate_property",    ["Duplicate data property in object literal not allowed in strict mode"],
        "accessor_data_property",       ["Object literal may not have data and accessor property with the same name"],
        "accessor_get_set",             ["Object literal may not have multiple get/set accessors with the same name"],
        "strict_lhs_assignment",        ["Assignment to eval or arguments is not allowed in strict mode"],
        "strict_lhs_postfix",           ["Postfix increment/decrement may not have eval or arguments operand in strict mode"],
        "strict_lhs_prefix",            ["Prefix increment/decrement may not have eval or arguments operand in strict mode"],
        "strict_reserved_word",         ["Use of future reserved word in strict mode"],
        "strict_delete",                ["Delete of an unqualified identifier in strict mode."],
        "strict_delete_property",       ["Cannot delete property '", "%0", "' of ", "%1"],
        "strict_const",                 ["Use of const in strict mode."],
        "strict_function",              ["In strict mode code, functions can only be declared at top level or immediately within another function." ],
        "strict_read_only_property",    ["Cannot assign to read only property '", "%0", "' of ", "%1"],
        "strict_cannot_assign",         ["Cannot assign to read only '", "%0", "' in strict mode"],
        "strict_poison_pill",           ["'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them"],
        "strict_caller",                ["Illegal access to a strict mode caller function."],
        "unprotected_let",              ["Illegal let declaration in unprotected statement context."],
        "unprotected_const",            ["Illegal const declaration in unprotected statement context."],
        "cant_prevent_ext_external_array_elements", ["Cannot prevent extension of an object with external array elements"],
        "redef_external_array_element", ["Cannot redefine a property of an object with external array elements"],
        "harmony_const_assign",         ["Assignment to constant variable."],
        "invalid_module_path",          ["Module does not export '", "%0", "', or export is not itself a module"],
        "module_type_error",            ["Module '", "%0", "' used improperly"],
      ];
      var messages = { __proto__ : null };
      for (var i = 0; i < messagesDictionary.length; i += 2) {
        var key = messagesDictionary[i];
        var format = messagesDictionary[i + 1];
  
        for (var j = 0; j < format.length; j++) {
          %IgnoreAttributesAndSetProperty(format, %_NumberToString(j), format[j],
                                          DONT_DELETE | READ_ONLY | DONT_ENUM);
        }
        %IgnoreAttributesAndSetProperty(format, 'length', format.length,
                                        DONT_DELETE | READ_ONLY | DONT_ENUM);
        %PreventExtensions(format);
        %IgnoreAttributesAndSetProperty(messages,
                                        key,
                                        format,
                                        DONT_DELETE | DONT_ENUM | READ_ONLY);
      }
      %PreventExtensions(messages);
      %IgnoreAttributesAndSetProperty(builtins, "kMessages",
                                      messages,
                                      DONT_DELETE | DONT_ENUM | READ_ONLY);
    }
    var message_type = %MessageGetType(message);
    var format = kMessages[message_type];
    if (!format) return "<unknown message " + message_type + ">";
    return FormatString(format, message);
  }
  
  
  function GetLineNumber(message) {
    var start_position = %MessageGetStartPosition(message);
    if (start_position == -1) return kNoLineNumberInfo;
    var script = %MessageGetScript(message);
    var location = script.locationFromPosition(start_position, true);
    if (location == null) return kNoLineNumberInfo;
    return location.line + 1;
  }
  
  
  // Returns the source code line containing the given source
  // position, or the empty string if the position is invalid.
  function GetSourceLine(message) {
    var script = %MessageGetScript(message);
    var start_position = %MessageGetStartPosition(message);
    var location = script.locationFromPosition(start_position, true);
    if (location == null) return "";
    location.restrict();
    return location.sourceText();
  }
  
  
  function MakeTypeError(type, args) {
    return MakeGenericError($TypeError, type, args);
  }
  
  
  function MakeRangeError(type, args) {
    return MakeGenericError($RangeError, type, args);
  }
  
  
  function MakeSyntaxError(type, args) {
    return MakeGenericError($SyntaxError, type, args);
  }
  
  
  function MakeReferenceError(type, args) {
    return MakeGenericError($ReferenceError, type, args);
  }
  
  
  function MakeEvalError(type, args) {
    return MakeGenericError($EvalError, type, args);
  }
  
  
  function MakeError(type, args) {
    return MakeGenericError($Error, type, args);
  }
  
  /**
   * Find a line number given a specific source position.
   * @param {number} position The source position.
   * @return {number} 0 if input too small, -1 if input too large,
         else the line number.
   */
  function ScriptLineFromPosition(position) {
    var lower = 0;
    var upper = this.lineCount() - 1;
    var line_ends = this.line_ends;
  
    // We'll never find invalid positions so bail right away.
    if (position > line_ends[upper]) {
      return -1;
    }
  
    // This means we don't have to safe-guard indexing line_ends[i - 1].
    if (position <= line_ends[0]) {
      return 0;
    }
  
    // Binary search to find line # from position range.
    while (upper >= 1) {
      var i = (lower + upper) >> 1;
  
      if (position > line_ends[i]) {
        lower = i + 1;
      } else if (position <= line_ends[i - 1]) {
        upper = i - 1;
      } else {
        return i;
      }
    }
  
    return -1;
  }
  
  /**
   * Get information on a specific source position.
   * @param {number} position The source position
   * @param {boolean} include_resource_offset Set to true to have the resource
   *     offset added to the location
   * @return {SourceLocation}
   *     If line is negative or not in the source null is returned.
   */
  function ScriptLocationFromPosition(position,
                                      include_resource_offset) {
    var line = this.lineFromPosition(position);
    if (line == -1) return null;
  
    // Determine start, end and column.
    var line_ends = this.line_ends;
    var start = line == 0 ? 0 : line_ends[line - 1] + 1;
    var end = line_ends[line];
    if (end > 0 && %_CallFunction(this.source, end - 1, StringCharAt) == '\r') {
      end--;
    }
    var column = position - start;
  
    // Adjust according to the offset within the resource.
    if (include_resource_offset) {
      line += this.line_offset;
      if (line == this.line_offset) {
        column += this.column_offset;
      }
    }
  
    return new SourceLocation(this, position, line, column, start, end);
  }
  
  
  /**
   * Get information on a specific source line and column possibly offset by a
   * fixed source position. This function is used to find a source position from
   * a line and column position. The fixed source position offset is typically
   * used to find a source position in a function based on a line and column in
   * the source for the function alone. The offset passed will then be the
   * start position of the source for the function within the full script source.
   * @param {number} opt_line The line within the source. Default value is 0
   * @param {number} opt_column The column in within the line. Default value is 0
   * @param {number} opt_offset_position The offset from the begining of the
   *     source from where the line and column calculation starts.
   *     Default value is 0
   * @return {SourceLocation}
   *     If line is negative or not in the source null is returned.
   */
  function ScriptLocationFromLine(opt_line, opt_column, opt_offset_position) {
    // Default is the first line in the script. Lines in the script is relative
    // to the offset within the resource.
    var line = 0;
    if (!IS_UNDEFINED(opt_line)) {
      line = opt_line - this.line_offset;
    }
  
    // Default is first column. If on the first line add the offset within the
    // resource.
    var column = opt_column || 0;
    if (line == 0) {
      column -= this.column_offset;
    }
  
    var offset_position = opt_offset_position || 0;
    if (line < 0 || column < 0 || offset_position < 0) return null;
    if (line == 0) {
      return this.locationFromPosition(offset_position + column, false);
    } else {
      // Find the line where the offset position is located.
      var offset_line = this.lineFromPosition(offset_position);
  
      if (offset_line == -1 || offset_line + line >= this.lineCount()) {
        return null;
      }
  
      return this.locationFromPosition(
          this.line_ends[offset_line + line - 1] + 1 + column);  // line > 0 here.
    }
  }
  
  
  /**
   * Get a slice of source code from the script. The boundaries for the slice is
   * specified in lines.
   * @param {number} opt_from_line The first line (zero bound) in the slice.
   *     Default is 0
   * @param {number} opt_to_column The last line (zero bound) in the slice (non
   *     inclusive). Default is the number of lines in the script
   * @return {SourceSlice} The source slice or null of the parameters where
   *     invalid
   */
  function ScriptSourceSlice(opt_from_line, opt_to_line) {
    var from_line = IS_UNDEFINED(opt_from_line) ? this.line_offset
                                                : opt_from_line;
    var to_line = IS_UNDEFINED(opt_to_line) ? this.line_offset + this.lineCount()
                                            : opt_to_line;
  
    // Adjust according to the offset within the resource.
    from_line -= this.line_offset;
    to_line -= this.line_offset;
    if (from_line < 0) from_line = 0;
    if (to_line > this.lineCount()) to_line = this.lineCount();
  
    // Check parameters.
    if (from_line >= this.lineCount() ||
        to_line < 0 ||
        from_line > to_line) {
      return null;
    }
  
    var line_ends = this.line_ends;
    var from_position = from_line == 0 ? 0 : line_ends[from_line - 1] + 1;
    var to_position = to_line == 0 ? 0 : line_ends[to_line - 1] + 1;
  
    // Return a source slice with line numbers re-adjusted to the resource.
    return new SourceSlice(this,
                           from_line + this.line_offset,
                           to_line + this.line_offset,
                            from_position, to_position);
  }
  
  
  function ScriptSourceLine(opt_line) {
    // Default is the first line in the script. Lines in the script are relative
    // to the offset within the resource.
    var line = 0;
    if (!IS_UNDEFINED(opt_line)) {
      line = opt_line - this.line_offset;
    }
  
    // Check parameter.
    if (line < 0 || this.lineCount() <= line) {
      return null;
    }
  
    // Return the source line.
    var line_ends = this.line_ends;
    var start = line == 0 ? 0 : line_ends[line - 1] + 1;
    var end = line_ends[line];
    return %_CallFunction(this.source, start, end, StringSubstring);
  }
  
  
  /**
   * Returns the number of source lines.
   * @return {number}
   *     Number of source lines.
   */
  function ScriptLineCount() {
    // Return number of source lines.
    return this.line_ends.length;
  }
  
  
  /**
   * Returns the name of script if available, contents of sourceURL comment
   * otherwise. See
   * http://fbug.googlecode.com/svn/branches/firebug1.1/docs/ReleaseNotes_1.1.txt
   * for details on using //@ sourceURL comment to identify scritps that don't
   * have name.
   *
   * @return {?string} script name if present, value for //@ sourceURL comment
   * otherwise.
   */
  function ScriptNameOrSourceURL() {
    if (this.name) {
      return this.name;
    }
  
    // The result is cached as on long scripts it takes noticable time to search
    // for the sourceURL.
    if (this.hasCachedNameOrSourceURL)
        return this.cachedNameOrSourceURL;
    this.hasCachedNameOrSourceURL = true;
  
    // TODO(608): the spaces in a regexp below had to be escaped as \040
    // because this file is being processed by js2c whose handling of spaces
    // in regexps is broken. Also, ['"] are excluded from allowed URLs to
    // avoid matches against sources that invoke evals with sourceURL.
    // A better solution would be to detect these special comments in
    // the scanner/parser.
    var source = ToString(this.source);
    var sourceUrlPos = %StringIndexOf(source, "sourceURL=", 0);
    this.cachedNameOrSourceURL = this.name;
    if (sourceUrlPos > 4) {
      var sourceUrlPattern =
          /\/\/@[\040\t]sourceURL=[\040\t]*([^\s\'\"]*)[\040\t]*$/gm;
      // Don't reuse lastMatchInfo here, so we create a new array with room
      // for four captures (array with length one longer than the index
      // of the fourth capture, where the numbering is zero-based).
      var matchInfo = new InternalArray(CAPTURE(3) + 1);
      var match =
          %_RegExpExec(sourceUrlPattern, source, sourceUrlPos - 4, matchInfo);
      if (match) {
        this.cachedNameOrSourceURL =
            SubString(source, matchInfo[CAPTURE(2)], matchInfo[CAPTURE(3)]);
      }
    }
    return this.cachedNameOrSourceURL;
  }
  
  
  SetUpLockedPrototype(Script,
    $Array("source", "name", "line_ends", "line_offset", "column_offset",
           "cachedNameOrSourceURL", "hasCachedNameOrSourceURL" ),
    $Array(
      "lineFromPosition", ScriptLineFromPosition,
      "locationFromPosition", ScriptLocationFromPosition,
      "locationFromLine", ScriptLocationFromLine,
      "sourceSlice", ScriptSourceSlice,
      "sourceLine", ScriptSourceLine,
      "lineCount", ScriptLineCount,
      "nameOrSourceURL", ScriptNameOrSourceURL
    )
  );
  
  
  /**
   * Class for source location. A source location is a position within some
   * source with the following properties:
   *   script   : script object for the source
   *   line     : source line number
   *   column   : source column within the line
   *   position : position within the source
   *   start    : position of start of source context (inclusive)
   *   end      : position of end of source context (not inclusive)
   * Source text for the source context is the character interval
   * [start, end[. In most cases end will point to a newline character.
   * It might point just past the final position of the source if the last
   * source line does not end with a newline character.
   * @param {Script} script The Script object for which this is a location
   * @param {number} position Source position for the location
   * @param {number} line The line number for the location
   * @param {number} column The column within the line for the location
   * @param {number} start Source position for start of source context
   * @param {number} end Source position for end of source context
   * @constructor
   */
  function SourceLocation(script, position, line, column, start, end) {
    this.script = script;
    this.position = position;
    this.line = line;
    this.column = column;
    this.start = start;
    this.end = end;
  }
  
  var kLineLengthLimit = 78;
  
  /**
   * Restrict source location start and end positions to make the source slice
   * no more that a certain number of characters wide.
   * @param {number} opt_limit The with limit of the source text with a default
   *     of 78
   * @param {number} opt_before The number of characters to prefer before the
   *     position with a default value of 10 less that the limit
   */
  function SourceLocationRestrict(opt_limit, opt_before) {
    // Find the actual limit to use.
    var limit;
    var before;
    if (!IS_UNDEFINED(opt_limit)) {
      limit = opt_limit;
    } else {
      limit = kLineLengthLimit;
    }
    if (!IS_UNDEFINED(opt_before)) {
      before = opt_before;
    } else {
      // If no before is specified center for small limits and perfer more source
      // before the the position that after for longer limits.
      if (limit <= 20) {
        before = $floor(limit / 2);
      } else {
        before = limit - 10;
      }
    }
    if (before >= limit) {
      before = limit - 1;
    }
  
    // If the [start, end[ interval is too big we restrict
    // it in one or both ends. We make sure to always produce
    // restricted intervals of maximum allowed size.
    if (this.end - this.start > limit) {
      var start_limit = this.position - before;
      var end_limit = this.position + limit - before;
      if (this.start < start_limit && end_limit < this.end) {
        this.start = start_limit;
        this.end = end_limit;
      } else if (this.start < start_limit) {
        this.start = this.end - limit;
      } else {
        this.end = this.start + limit;
      }
    }
  }
  
  
  /**
   * Get the source text for a SourceLocation
   * @return {String}
   *     Source text for this location.
   */
  function SourceLocationSourceText() {
    return %_CallFunction(this.script.source,
                          this.start,
                          this.end,
                          StringSubstring);
  }
  
  
  SetUpLockedPrototype(SourceLocation,
    $Array("script", "position", "line", "column", "start", "end"),
    $Array(
      "restrict", SourceLocationRestrict,
      "sourceText", SourceLocationSourceText
   )
  );
  
  
  /**
   * Class for a source slice. A source slice is a part of a script source with
   * the following properties:
   *   script        : script object for the source
   *   from_line     : line number for the first line in the slice
   *   to_line       : source line number for the last line in the slice
   *   from_position : position of the first character in the slice
   *   to_position   : position of the last character in the slice
   * The to_line and to_position are not included in the slice, that is the lines
   * in the slice are [from_line, to_line[. Likewise the characters in the slice
   * are [from_position, to_position[.
   * @param {Script} script The Script object for the source slice
   * @param {number} from_line
   * @param {number} to_line
   * @param {number} from_position
   * @param {number} to_position
   * @constructor
   */
  function SourceSlice(script, from_line, to_line, from_position, to_position) {
    this.script = script;
    this.from_line = from_line;
    this.to_line = to_line;
    this.from_position = from_position;
    this.to_position = to_position;
  }
  
  /**
   * Get the source text for a SourceSlice
   * @return {String} Source text for this slice. The last line will include
   *     the line terminating characters (if any)
   */
  function SourceSliceSourceText() {
    return %_CallFunction(this.script.source,
                          this.from_position,
                          this.to_position,
                          StringSubstring);
  }
  
  SetUpLockedPrototype(SourceSlice,
    $Array("script", "from_line", "to_line", "from_position", "to_position"),
    $Array("sourceText", SourceSliceSourceText)
  );
  
  
  // Returns the offset of the given position within the containing
  // line.
  function GetPositionInLine(message) {
    var script = %MessageGetScript(message);
    var start_position = %MessageGetStartPosition(message);
    var location = script.locationFromPosition(start_position, false);
    if (location == null) return -1;
    location.restrict();
    return start_position - location.start;
  }
  
  
  function GetStackTraceLine(recv, fun, pos, isGlobal) {
    return new CallSite(recv, fun, pos).toString();
  }
  
  // ----------------------------------------------------------------------------
  // Error implementation
  
  // Defines accessors for a property that is calculated the first time
  // the property is read.
  function DefineOneShotAccessor(obj, name, fun) {
    // Note that the accessors consistently operate on 'obj', not 'this'.
    // Since the object may occur in someone else's prototype chain we
    // can't rely on 'this' being the same as 'obj'.
    var hasBeenSet = false;
    var value;
    var getter = function() {
      if (hasBeenSet) {
        return value;
      }
      hasBeenSet = true;
      value = fun(obj);
      return value;
    };
    var setter = function(v) {
      hasBeenSet = true;
      value = v;
    };
    %DefineOrRedefineAccessorProperty(obj, name, getter, setter, DONT_ENUM);
  }
  
  function CallSite(receiver, fun, pos) {
    this.receiver = receiver;
    this.fun = fun;
    this.pos = pos;
  }
  
  function CallSiteGetThis() {
    return this.receiver;
  }
  
  function CallSiteGetTypeName() {
    return GetTypeName(this, false);
  }
  
  function CallSiteIsToplevel() {
    if (this.receiver == null) {
      return true;
    }
    return IS_GLOBAL(this.receiver);
  }
  
  function CallSiteIsEval() {
    var script = %FunctionGetScript(this.fun);
    return script && script.compilation_type == COMPILATION_TYPE_EVAL;
  }
  
  function CallSiteGetEvalOrigin() {
    var script = %FunctionGetScript(this.fun);
    return FormatEvalOrigin(script);
  }
  
  function CallSiteGetScriptNameOrSourceURL() {
    var script = %FunctionGetScript(this.fun);
    return script ? script.nameOrSourceURL() : null;
  }
  
  function CallSiteGetFunction() {
    return this.fun;
  }
  
  function CallSiteGetFunctionName() {
    // See if the function knows its own name
    var name = this.fun.name;
    if (name) {
      return name;
    }
    name = %FunctionGetInferredName(this.fun);
    if (name) {
      return name;
    }
    // Maybe this is an evaluation?
    var script = %FunctionGetScript(this.fun);
    if (script && script.compilation_type == COMPILATION_TYPE_EVAL) {
      return "eval";
    }
    return null;
  }
  
  function CallSiteGetMethodName() {
    // See if we can find a unique property on the receiver that holds
    // this function.
    var ownName = this.fun.name;
    if (ownName && this.receiver &&
        (%_CallFunction(this.receiver,
                        ownName,
                        ObjectLookupGetter) === this.fun ||
         %_CallFunction(this.receiver,
                        ownName,
                        ObjectLookupSetter) === this.fun ||
         this.receiver[ownName] === this.fun)) {
      // To handle DontEnum properties we guess that the method has
      // the same name as the function.
      return ownName;
    }
    var name = null;
    for (var prop in this.receiver) {
      if (this.receiver.__lookupGetter__(prop) === this.fun ||
          this.receiver.__lookupSetter__(prop) === this.fun ||
          (!this.receiver.__lookupGetter__(prop) &&
           this.receiver[prop] === this.fun)) {
        // If we find more than one match bail out to avoid confusion.
        if (name) {
          return null;
        }
        name = prop;
      }
    }
    if (name) {
      return name;
    }
    return null;
  }
  
  function CallSiteGetFileName() {
    var script = %FunctionGetScript(this.fun);
    return script ? script.name : null;
  }
  
  function CallSiteGetLineNumber() {
    if (this.pos == -1) {
      return null;
    }
    var script = %FunctionGetScript(this.fun);
    var location = null;
    if (script) {
      location = script.locationFromPosition(this.pos, true);
    }
    return location ? location.line + 1 : null;
  }
  
  function CallSiteGetColumnNumber() {
    if (this.pos == -1) {
      return null;
    }
    var script = %FunctionGetScript(this.fun);
    var location = null;
    if (script) {
      location = script.locationFromPosition(this.pos, true);
    }
    return location ? location.column + 1: null;
  }
  
  function CallSiteIsNative() {
    var script = %FunctionGetScript(this.fun);
    return script ? (script.type == TYPE_NATIVE) : false;
  }
  
  function CallSiteGetPosition() {
    return this.pos;
  }
  
  function CallSiteIsConstructor() {
    var constructor = this.receiver ? this.receiver.constructor : null;
    if (!constructor) {
      return false;
    }
    return this.fun === constructor;
  }
  
  function CallSiteToString() {
    var fileName;
    var fileLocation = "";
    if (this.isNative()) {
      fileLocation = "native";
    } else if (this.isEval()) {
      fileName = this.getScriptNameOrSourceURL();
      if (!fileName) {
        fileLocation = this.getEvalOrigin();
      }
    } else {
      fileName = this.getFileName();
    }
  
    if (fileName) {
      fileLocation += fileName;
      var lineNumber = this.getLineNumber();
      if (lineNumber != null) {
        fileLocation += ":" + lineNumber;
        var columnNumber = this.getColumnNumber();
        if (columnNumber) {
          fileLocation += ":" + columnNumber;
        }
      }
    }
  
    if (!fileLocation) {
      fileLocation = "unknown source";
    }
    var line = "";
    var functionName = this.getFunctionName();
    var addSuffix = true;
    var isConstructor = this.isConstructor();
    var isMethodCall = !(this.isToplevel() || isConstructor);
    if (isMethodCall) {
      var typeName = GetTypeName(this, true);
      var methodName = this.getMethodName();
      if (functionName) {
        if (typeName && functionName.indexOf(typeName) != 0) {
          line += typeName + ".";
        }
        line += functionName;
        if (methodName && functionName.lastIndexOf("." + methodName) !=
            functionName.length - methodName.length - 1) {
          line += " [as " + methodName + "]";
        }
      } else {
        line += typeName + "." + (methodName || "<anonymous>");
      }
    } else if (isConstructor) {
      line += "new " + (functionName || "<anonymous>");
    } else if (functionName) {
      line += functionName;
    } else {
      line += fileLocation;
      addSuffix = false;
    }
    if (addSuffix) {
      line += " (" + fileLocation + ")";
    }
    return line;
  }
  
  SetUpLockedPrototype(CallSite, $Array("receiver", "fun", "pos"), $Array(
    "getThis", CallSiteGetThis,
    "getTypeName", CallSiteGetTypeName,
    "isToplevel", CallSiteIsToplevel,
    "isEval", CallSiteIsEval,
    "getEvalOrigin", CallSiteGetEvalOrigin,
    "getScriptNameOrSourceURL", CallSiteGetScriptNameOrSourceURL,
    "getFunction", CallSiteGetFunction,
    "getFunctionName", CallSiteGetFunctionName,
    "getMethodName", CallSiteGetMethodName,
    "getFileName", CallSiteGetFileName,
    "getLineNumber", CallSiteGetLineNumber,
    "getColumnNumber", CallSiteGetColumnNumber,
    "isNative", CallSiteIsNative,
    "getPosition", CallSiteGetPosition,
    "isConstructor", CallSiteIsConstructor,
    "toString", CallSiteToString
  ));
  
  
  function FormatEvalOrigin(script) {
    var sourceURL = script.nameOrSourceURL();
    if (sourceURL) {
      return sourceURL;
    }
  
    var eval_origin = "eval at ";
    if (script.eval_from_function_name) {
      eval_origin += script.eval_from_function_name;
    } else {
      eval_origin +=  "<anonymous>";
    }
  
    var eval_from_script = script.eval_from_script;
    if (eval_from_script) {
      if (eval_from_script.compilation_type == COMPILATION_TYPE_EVAL) {
        // eval script originated from another eval.
        eval_origin += " (" + FormatEvalOrigin(eval_from_script) + ")";
      } else {
        // eval script originated from "real" source.
        if (eval_from_script.name) {
          eval_origin += " (" + eval_from_script.name;
          var location = eval_from_script.locationFromPosition(
              script.eval_from_script_position, true);
          if (location) {
            eval_origin += ":" + (location.line + 1);
            eval_origin += ":" + (location.column + 1);
          }
          eval_origin += ")";
        } else {
          eval_origin += " (unknown source)";
        }
      }
    }
  
    return eval_origin;
  }
  
  function FormatStackTrace(error, frames) {
    var lines = [];
    try {
      lines.push(error.toString());
    } catch (e) {
      try {
        lines.push("<error: " + e + ">");
      } catch (ee) {
        lines.push("<error>");
      }
    }
    for (var i = 0; i < frames.length; i++) {
      var frame = frames[i];
      var line;
      try {
        line = frame.toString();
      } catch (e) {
        try {
          line = "<error: " + e + ">";
        } catch (ee) {
          // Any code that reaches this point is seriously nasty!
          line = "<error>";
        }
      }
      lines.push("    at " + line);
    }
    return lines.join("\n");
  }
  
  function FormatRawStackTrace(error, raw_stack) {
    var frames = [ ];
    for (var i = 0; i < raw_stack.length; i += 4) {
      var recv = raw_stack[i];
      var fun = raw_stack[i + 1];
      var code = raw_stack[i + 2];
      var pc = raw_stack[i + 3];
      var pos = %FunctionGetPositionForOffset(code, pc);
      frames.push(new CallSite(recv, fun, pos));
    }
    if (IS_FUNCTION($Error.prepareStackTrace)) {
      return $Error.prepareStackTrace(error, frames);
    } else {
      return FormatStackTrace(error, frames);
    }
  }
  
  function GetTypeName(obj, requireConstructor) {
    var constructor = obj.receiver.constructor;
    if (!constructor) {
      return requireConstructor ? null :
          %_CallFunction(obj.receiver, ObjectToString);
    }
    var constructorName = constructor.name;
    if (!constructorName) {
      return requireConstructor ? null :
          %_CallFunction(obj.receiver, ObjectToString);
    }
    return constructorName;
  }
  
  function captureStackTrace(obj, cons_opt) {
    var stackTraceLimit = $Error.stackTraceLimit;
    if (!stackTraceLimit || !IS_NUMBER(stackTraceLimit)) return;
    if (stackTraceLimit < 0 || stackTraceLimit > 10000) {
      stackTraceLimit = 10000;
    }
    var raw_stack = %CollectStackTrace(obj,
                                       cons_opt ? cons_opt : captureStackTrace,
                                       stackTraceLimit);
    DefineOneShotAccessor(obj, 'stack', function (obj) {
      return FormatRawStackTrace(obj, raw_stack);
    });
  }
  
  
  function SetUpError() {
    // Define special error type constructors.
  
    var DefineError = function(f) {
      // Store the error function in both the global object
      // and the runtime object. The function is fetched
      // from the runtime object when throwing errors from
      // within the runtime system to avoid strange side
      // effects when overwriting the error functions from
      // user code.
      var name = f.name;
      %SetProperty(global, name, f, DONT_ENUM);
      %SetProperty(builtins, '$' + name, f, DONT_ENUM | DONT_DELETE | READ_ONLY);
      // Configure the error function.
      if (name == 'Error') {
        // The prototype of the Error object must itself be an error.
        // However, it can't be an instance of the Error object because
        // it hasn't been properly configured yet.  Instead we create a
        // special not-a-true-error-but-close-enough object.
        var ErrorPrototype = function() {};
        %FunctionSetPrototype(ErrorPrototype, $Object.prototype);
        %FunctionSetInstanceClassName(ErrorPrototype, 'Error');
        %FunctionSetPrototype(f, new ErrorPrototype());
      } else {
        %FunctionSetPrototype(f, new $Error());
      }
      %FunctionSetInstanceClassName(f, 'Error');
      %SetProperty(f.prototype, 'constructor', f, DONT_ENUM);
      %SetProperty(f.prototype, "name", name, DONT_ENUM);
      %SetCode(f, function(m) {
        if (%_IsConstructCall()) {
          // Define all the expected properties directly on the error
          // object. This avoids going through getters and setters defined
          // on prototype objects.
          %IgnoreAttributesAndSetProperty(this, 'stack', void 0, DONT_ENUM);
          %IgnoreAttributesAndSetProperty(this, 'arguments', void 0, DONT_ENUM);
          %IgnoreAttributesAndSetProperty(this, 'type', void 0, DONT_ENUM);
          if (m === kAddMessageAccessorsMarker) {
            // DefineOneShotAccessor always inserts a message property and
            // ignores setters.
            DefineOneShotAccessor(this, 'message', function (obj) {
                return FormatMessage(%NewMessageObject(obj.type, obj.arguments));
            });
          } else if (!IS_UNDEFINED(m)) {
            %IgnoreAttributesAndSetProperty(
              this, 'message', ToString(m), DONT_ENUM);
          }
          captureStackTrace(this, f);
        } else {
          return new f(m);
        }
      });
      %SetNativeFlag(f);
    };
  
    DefineError(function Error() { });
    DefineError(function TypeError() { });
    DefineError(function RangeError() { });
    DefineError(function SyntaxError() { });
    DefineError(function ReferenceError() { });
    DefineError(function EvalError() { });
    DefineError(function URIError() { });
  }
  
  SetUpError();
  
  $Error.captureStackTrace = captureStackTrace;
  
  %SetProperty($Error.prototype, 'message', '', DONT_ENUM);
  
  // Global list of error objects visited during ErrorToString. This is
  // used to detect cycles in error toString formatting.
  var visited_errors = new InternalArray();
  var cyclic_error_marker = new $Object();
  
  function GetPropertyWithoutInvokingMonkeyGetters(error, name) {
    // Climb the prototype chain until we find the holder.
    while (error && !%HasLocalProperty(error, name)) {
      error = error.__proto__;
    }
    if (error === null) return void 0;
    if (!IS_OBJECT(error)) return error[name];
    // If the property is an accessor on one of the predefined errors that can be
    // generated statically by the compiler, don't touch it. This is to address
    // http://code.google.com/p/chromium/issues/detail?id=69187
    var desc = %GetOwnProperty(error, name);
    if (desc && desc[IS_ACCESSOR_INDEX]) {
      var isName = name === "name";
      if (error === $ReferenceError.prototype)
        return isName ? "ReferenceError" : void 0;
      if (error === $SyntaxError.prototype)
        return isName ? "SyntaxError" : void 0;
      if (error === $TypeError.prototype)
        return isName ? "TypeError" : void 0;
    }
    // Otherwise, read normally.
    return error[name];
  }
  
  function ErrorToStringDetectCycle(error) {
    if (!%PushIfAbsent(visited_errors, error)) throw cyclic_error_marker;
    try {
      var type = GetPropertyWithoutInvokingMonkeyGetters(error, "type");
      var name = GetPropertyWithoutInvokingMonkeyGetters(error, "name");
      name = IS_UNDEFINED(name) ? "Error" : TO_STRING_INLINE(name);
      var message = GetPropertyWithoutInvokingMonkeyGetters(error, "message");
      var hasMessage = %_CallFunction(error, "message", ObjectHasOwnProperty);
      if (type && !hasMessage) {
        var args = GetPropertyWithoutInvokingMonkeyGetters(error, "arguments");
        message = FormatMessage(%NewMessageObject(type, args));
      }
      message = IS_UNDEFINED(message) ? "" : TO_STRING_INLINE(message);
      if (name === "") return message;
      if (message === "") return name;
      return name + ": " + message;
    } finally {
      visited_errors.length = visited_errors.length - 1;
    }
  }
  
  function ErrorToString() {
    if (!IS_SPEC_OBJECT(this)) {
      throw MakeTypeError("called_on_non_object", ["Error.prototype.toString"]);
    }
  
    try {
      return ErrorToStringDetectCycle(this);
    } catch(e) {
      // If this error message was encountered already return the empty
      // string for it instead of recursively formatting it.
      if (e === cyclic_error_marker) {
        return '';
      }
      throw e;
    }
  }
  
  
  InstallFunctions($Error.prototype, DONT_ENUM, ['toString', ErrorToString]);
  
  // Boilerplate for exceptions for stack overflows. Used from
  // Isolate::StackOverflow().
  var kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);
  