CSE2410 Fall 2014 Bounce

// 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.

// -------------------------------------------------------------------

var kMessages = {

  // Error

  cyclic_proto:                  ["Cyclic __proto__ value"],

  code_gen_from_strings:         ["%0"],

  generator_running:             ["Generator is already running"],

  generator_finished:            ["Generator has already finished"],

  // 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"],

  undefined_or_null_to_object:   ["Cannot convert undefined or 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"],

  invalid_weakset_value:         ["Invalid value used in weak set"],

  not_date_object:               ["this is not a Date object."],

  observe_non_object:            ["Object.", "%0", " cannot ", "%0", " non-object"],

  observe_non_function:          ["Object.", "%0", " cannot deliver to non-function"],

  observe_callback_frozen:       ["Object.observe cannot deliver to a frozen function object"],

  observe_invalid_accept:        ["Object.observe accept must be an array of strings."],

  observe_type_non_string:       ["Invalid changeRecord with non-string 'type' property"],

  observe_perform_non_string:    ["Invalid non-string changeType"],

  observe_perform_non_function:  ["Cannot perform non-function"],

  observe_notify_non_notifier:   ["notify called on non-notifier object"],

  proto_poison_pill:             ["Generic use of __proto__ accessor not allowed"],

  not_typed_array:               ["this is not a typed array."],

  invalid_argument:              ["invalid_argument"],

  data_view_not_array_buffer:    ["First argument to DataView constructor must be an ArrayBuffer"],

  constructor_not_function:      ["Constructor ", "%0", " requires 'new'"],

  // RangeError

  invalid_array_length:          ["Invalid array length"],

  invalid_array_buffer_length:   ["Invalid array buffer length"],

  invalid_typed_array_offset:    ["Start offset is too large:"],

  invalid_typed_array_length:    ["Invalid typed array length"],

  invalid_typed_array_alignment: ["%0", "of", "%1", "should be a multiple of", "%3"],

  typed_array_set_source_too_large:

                                 ["Source is too large"],

  typed_array_set_negative_offset:

                                 ["Start offset is negative"],

  invalid_data_view_offset:      ["Start offset is outside the bounds of the buffer"],

  invalid_data_view_length:      ["Invalid data view length"],

  invalid_data_view_accessor_offset:

                                 ["Offset is outside the bounds of the DataView"],

  stack_overflow:                ["Maximum call stack size exceeded"],

  invalid_time_value:            ["Invalid time value"],

  invalid_count_value:           ["Invalid count value"],

  // SyntaxError

  paren_in_arg_string:           ["Function arg string contains parenthesis"],

  not_isvar:                     ["builtin %IS_VAR: not a variable"],

  single_function_literal:       ["Single function literal required"],

  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 131071 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."],

  symbol_to_string:              ["Conversion from symbol to string"],

  invalid_module_path:           ["Module does not export '", "%0", "', or export is not itself a module"],

  module_type_error:             ["Module '", "%0", "' used improperly"],

  module_export_undefined:       ["Export '", "%0", "' is not defined in module"]

};

function FormatString(format, args) {

  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 = 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_FUNCTION(obj)) return  %_CallFunction(obj, FunctionToString);

  if (IS_OBJECT(obj) && %GetDataProperty(obj, "toString") === ObjectToString) {

    var constructor = %GetDataProperty(obj, "constructor");

    if (typeof constructor == "function") {

      var constructorName = constructor.name;

      if (IS_STRING(constructorName) && constructorName !== "") {

        return "#<" + constructorName + ">";

      }

    }

  }

  if (CanBeSafelyTreatedAsAnErrorObject(obj)) {

    return %_CallFunction(obj, ErrorToString);

  }

  return %_CallFunction(obj, ObjectToString);

}

// To determine whether we can safely stringify an object using ErrorToString

// without the risk of side-effects, we need to check whether the object is

// either an instance of a native error type (via '%_ClassOf'), or has $Error

// in its prototype chain and hasn't overwritten 'toString' with something

// strange and unusual.

function CanBeSafelyTreatedAsAnErrorObject(obj) {

  switch (%_ClassOf(obj)) {

    case 'Error':

    case 'EvalError':

    case 'RangeError':

    case 'ReferenceError':

    case 'SyntaxError':

    case 'TypeError':

    case 'URIError':

      return true;

  }

  var objToString = %GetDataProperty(obj, "toString");

  return obj instanceof $Error && objToString === ErrorToString;

}

// 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 (CanBeSafelyTreatedAsAnErrorObject(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 = [];

  return new constructor(FormatMessage(type, args));

}

/**

 * 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(type, args) {

  var format = kMessages[type];

  if (!format) return "<unknown message " + type + ">";

  return FormatString(format, args);

}

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;

}

/**

 * If sourceURL comment is available and script starts at zero returns sourceURL

 * comment contents. Otherwise, script name is returned. See

 * http://fbug.googlecode.com/svn/branches/firebug1.1/docs/ReleaseNotes_1.1.txt

 * and Source Map Revision 3 proposal for details on using //# sourceURL and

 * deprecated //@ sourceURL comment to identify scripts that don't have name.

 *

 * @return {?string} script name if present, value for //# sourceURL or

 * deprecated //@ sourceURL comment otherwise.

 */

function ScriptNameOrSourceURL() {

  if (this.line_offset > 0 || this.column_offset > 0) {

    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, false).toString();

}

// ----------------------------------------------------------------------------

// Error implementation

var CallSiteReceiverKey = %CreateSymbol("receiver");

var CallSiteFunctionKey = %CreateSymbol("function");

var CallSitePositionKey = %CreateSymbol("position");

var CallSiteStrictModeKey = %CreateSymbol("strict mode");

function CallSite(receiver, fun, pos, strict_mode) {

  this[CallSiteReceiverKey] = receiver;

  this[CallSiteFunctionKey] = fun;

  this[CallSitePositionKey] = pos;

  this[CallSiteStrictModeKey] = strict_mode;

}

function CallSiteGetThis() {

  return this[CallSiteStrictModeKey] ? UNDEFINED : this[CallSiteReceiverKey];

}

function CallSiteGetTypeName() {

  return GetTypeName(this[CallSiteReceiverKey], false);

}

function CallSiteIsToplevel() {

  if (this[CallSiteReceiverKey] == null) {

    return true;

  }

  return IS_GLOBAL(this[CallSiteReceiverKey]);

}

function CallSiteIsEval() {

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  return script && script.compilation_type == COMPILATION_TYPE_EVAL;

}

function CallSiteGetEvalOrigin() {

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  return FormatEvalOrigin(script);

}

function CallSiteGetScriptNameOrSourceURL() {

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  return script ? script.nameOrSourceURL() : null;

}

function CallSiteGetFunction() {

  return this[CallSiteStrictModeKey] ? UNDEFINED : this[CallSiteFunctionKey];

}

function CallSiteGetFunctionName() {

  // See if the function knows its own name

  var name = this[CallSiteFunctionKey].name;

  if (name) {

    return name;

  }

  name = %FunctionGetInferredName(this[CallSiteFunctionKey]);

  if (name) {

    return name;

  }

  // Maybe this is an evaluation?

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  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 receiver = this[CallSiteReceiverKey];

  var fun = this[CallSiteFunctionKey];

  var ownName = fun.name;

  if (ownName && receiver &&

      (%_CallFunction(receiver, ownName, ObjectLookupGetter) === fun ||

       %_CallFunction(receiver, ownName, ObjectLookupSetter) === fun ||

       (IS_OBJECT(receiver) && %GetDataProperty(receiver, ownName) === 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 receiver) {

    if (%_CallFunction(receiver, prop, ObjectLookupGetter) === fun ||

        %_CallFunction(receiver, prop, ObjectLookupSetter) === fun ||

        (IS_OBJECT(receiver) && %GetDataProperty(receiver, prop) === 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[CallSiteFunctionKey]);

  return script ? script.name : null;

}

function CallSiteGetLineNumber() {

  if (this[CallSitePositionKey] == -1) {

    return null;

  }

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  var location = null;

  if (script) {

    location = script.locationFromPosition(this[CallSitePositionKey], true);

  }

  return location ? location.line + 1 : null;

}

function CallSiteGetColumnNumber() {

  if (this[CallSitePositionKey] == -1) {

    return null;

  }

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  var location = null;

  if (script) {

    location = script.locationFromPosition(this[CallSitePositionKey], true);

  }

  return location ? location.column + 1: null;

}

function CallSiteIsNative() {

  var script = %FunctionGetScript(this[CallSiteFunctionKey]);

  return script ? (script.type == TYPE_NATIVE) : false;

}

function CallSiteGetPosition() {

  return this[CallSitePositionKey];

}

function CallSiteIsConstructor() {

  var receiver = this[CallSiteReceiverKey];

  var constructor = (receiver != null && IS_OBJECT(receiver))

                        ? %GetDataProperty(receiver, "constructor") : null;

  if (!constructor) return false;

  return this[CallSiteFunctionKey] === constructor;

}

function CallSiteToString() {

  var fileName;

  var fileLocation = "";

  if (this.isNative()) {

    fileLocation = "native";

  } else {

    if (this.isEval()) {

      fileName = this.getScriptNameOrSourceURL();

      if (!fileName) {

        fileLocation = this.getEvalOrigin();

        fileLocation += ", ";  // Expecting source position to follow.

      }

    } else {

      fileName = this.getFileName();

    }

    if (fileName) {

      fileLocation += fileName;

    } else {

      // Source code does not originate from a file and is not native, but we

      // can still get the source position inside the source string, e.g. in

      // an eval string.

      fileLocation += "<anonymous>";

    }

    var lineNumber = this.getLineNumber();

    if (lineNumber != null) {

      fileLocation += ":" + lineNumber;

      var columnNumber = this.getColumnNumber();

      if (columnNumber) {

        fileLocation += ":" + columnNumber;

      }

    }

  }

  var line = "";

  var functionName = this.getFunctionName();

  var addSuffix = true;

  var isConstructor = this.isConstructor();

  var isMethodCall = !(this.isToplevel() || isConstructor);

  if (isMethodCall) {

    var typeName = GetTypeName(this[CallSiteReceiverKey], true);

    var methodName = this.getMethodName();

    if (functionName) {

      if (typeName &&

          %_CallFunction(functionName, typeName, StringIndexOf) != 0) {

        line += typeName + ".";

      }

      line += functionName;

      if (methodName &&

          (%_CallFunction(functionName, "." + methodName, StringIndexOf) !=

           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 FormatErrorString(error) {

  try {

    return %_CallFunction(error, ErrorToString);

  } catch (e) {

    try {

      return "<error: " + e + ">";

    } catch (ee) {

      return "<error>";