Allow users to specify a scons build cache directory.

SConstruct

 # Copyright 2010 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 764 matching lines @@
     'default': 'off',
     'help': 'select profile guided optimization variant',
   }
 }
 
 
 def GetOptions():
   result = Options()
   result.Add('mode', 'compilation mode (debug, release)', 'release')
   result.Add('sample', 'build sample (shell, process, lineprocessor)', '')
+  result.Add('cache', 'directory to use for scons build cache', '')
   result.Add('env', 'override environment settings (NAME0:value0,NAME1:value1,...)', '')
   result.Add('importenv', 'import environment settings (NAME0,NAME1,...)', '')
   for (name, option) in SIMPLE_OPTIONS.iteritems():
     help = '%s (%s)' % (name, ", ".join(option['values']))
     result.Add(name, help, option.get('default'))
   return result
 
 
 def GetVersionComponents():
   MAJOR_VERSION_PATTERN = re.compile(r"#define\s+MAJOR_VERSION\s+(.*)")
@@ skipping 61 matching lines @@
   if env['os'] == 'win32' and env['library'] == 'shared' and env['prof'] == 'on':
     Abort("Profiling on windows only supported for static library.")
   if env['prof'] == 'oprofile' and env['os'] != 'linux':
     Abort("OProfile is only supported on Linux.")
   if env['os'] == 'win32' and env['soname'] == 'on':
     Abort("Shared Object soname not applicable for Windows.")
   if env['soname'] == 'on' and env['library'] == 'static':
     Abort("Shared Object soname not applicable for static library.")
   if env['os'] != 'win32' and env['pgo'] != 'off':
     Abort("Profile guided optimization only supported on Windows.")
+  if env['cache'] and not os.path.isdir(env['cache']):
+    Abort("The specified cache directory does not exist.")
   if not (env['arch'] == 'arm' or env['simulator'] == 'arm') and ('unalignedaccesses' in ARGUMENTS):
     print env['arch']
     print env['simulator']
     Abort("Option unalignedaccesses only supported for the ARM architecture.")
   for (name, option) in SIMPLE_OPTIONS.iteritems():
     if (not option.get('default')) and (name not in ARGUMENTS):
       message = ("A value for option %s must be specified (%s)." %
           (name, ", ".join(option['values'])))
       Abort(message)
     if not env[name] in option['values']:
@@ skipping 248 matching lines @@
   env.Alias('mksnapshot', mksnapshots)
   env.Alias('cctests', cctests)
   env.Alias('sample', samples)
   env.Alias('d8', d8s)
 
   if env['sample']:
     env.Default('sample')
   else:
     env.Default('library')
 
+  if env['cache']:
+    CacheDir(env['cache'])
 
 # We disable deprecation warnings because we need to be able to use
 # env.Copy without getting warnings for compatibility with older
 # version of scons.  Also, there's a bug in some revisions that
 # doesn't allow this flag to be set, so we swallow any exceptions.
 # Lovely.
 try:
   SetOption('warn', 'no-deprecated')
 except:
   pass
 
 
 Build()