Introduce experimental natives that are enabled by a runtime flag.

tools/js2c.py

 #!/usr/bin/env python
 #
 # Copyright 2006-2008 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 186 matching lines @@
           args = map(string.strip, python_match.group(2).split(','))
           body = python_match.group(3).strip()
           fun = eval("lambda " + ",".join(args) + ': ' + body)
           macros.append((re.compile("\\b%s\\(" % name), PythonMacro(args, fun)))
         else:
           raise ("Illegal line: " + line)
   return (constants, macros)
 
 
 HEADER_TEMPLATE = """\
-// Copyright 2008 Google Inc. All Rights Reserved.
+// Copyright 2011 Google Inc. All Rights Reserved.
 
 // This file was generated from .js source files by SCons.  If you
 // want to make changes to this file you should either change the
 // javascript source files or the SConstruct script.
 
 #include "v8.h"
 #include "natives.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 63 matching lines @@
     if 'macros.py' == (os.path.split(str(s))[1]):
       (consts, macros) = ReadMacros(ReadLines(str(s)))
     else:
       modules.append(s)
 
   # Build source code lines
   source_lines = [ ]
 
   minifier = jsmin.JavaScriptMinifier()
 
-  source_lines_empty = []
   for module in modules:
     filename = str(module)
     debugger = filename.endswith('-debugger.js')
     lines = ReadFile(filename)
     lines = ExpandConstants(lines, consts)
     lines = ExpandMacros(lines, macros)
     Validate(lines, filename)
     lines = minifier.JSMinify(lines)
     data = ToCArray(lines)
     id = (os.path.split(filename)[1])[:-3]
     if debugger: id = id[:-9]
     if debugger:
       debugger_ids.append((id, len(lines)))
     else:
       ids.append((id, len(lines)))
     source_lines.append(SOURCE_DECLARATION % { 'id': id, 'data': data })
-    source_lines_empty.append(SOURCE_DECLARATION % { 'id': id, 'data': data })
 
   # Build debugger support functions
   get_index_cases = [ ]
   get_script_source_cases = [ ]
   get_script_name_cases = [ ]
 
   i = 0
   for (id, length) in debugger_ids:
     native_name = "native %s.js" % id
     get_index_cases.append(GET_DEBUGGER_INDEX_CASE % { 'id': id, 'i': i })
@@ skipping 30 matching lines @@
     'builtin_count': len(ids) + len(debugger_ids),
     'debugger_count': len(debugger_ids),
     'source_lines': "\n".join(source_lines),
     'get_index_cases': "".join(get_index_cases),
     'get_script_source_cases': "".join(get_script_source_cases),
     'get_script_name_cases': "".join(get_script_name_cases),
     'type': env['TYPE']
   })
   output.close()
 
-  if len(target) > 1:
-    output = open(str(target[1]), "w")
-    output.write(HEADER_TEMPLATE % {
-      'builtin_count': len(ids) + len(debugger_ids),
-      'debugger_count': len(debugger_ids),
-      'source_lines': "\n".join(source_lines_empty),
-      'get_index_cases': "".join(get_index_cases),
-      'get_script_source_cases': "".join(get_script_source_cases),
-      'get_script_name_cases': "".join(get_script_name_cases),
-      'type': env['TYPE']
-    })
-    output.close()
-
 def main():
   natives = sys.argv[1]
-  natives_empty = sys.argv[2]
-  type = sys.argv[3]
-  source_files = sys.argv[4:]
-  JS2C(source_files, [natives, natives_empty], { 'TYPE': type })
+  type = sys.argv[2]
+  source_files = sys.argv[3:]
+  JS2C(source_files, [natives], { 'TYPE': type })
 
 if __name__ == "__main__":
   main()