Create the framework for adding a thumb2 backend for ARM. So far, it...

SConstruct

 # Copyright 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
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 160 matching lines @@
       'CCFLAGS':      ['-m32'],
       'LINKFLAGS':    ['-m32']
     },
     'arch:arm': {
       'CPPDEFINES':   ['V8_TARGET_ARCH_ARM']
     },
     'simulator:arm': {
       'CCFLAGS':      ['-m32'],
       'LINKFLAGS':    ['-m32']
     },
+    'armvariant:thumb2': {
+      'CPPDEFINES':   ['V8_ARM_VARIANT_THUMB']
+    },
+    'armvariant:arm': {
+      'CPPDEFINES':   ['V8_ARM_VARIANT_ARM']
+    },
     'arch:x64': {
       'CPPDEFINES':   ['V8_TARGET_ARCH_X64'],
       'CCFLAGS':      ['-m64'],
       'LINKFLAGS':    ['-m64'],
     },
     'prof:oprofile': {
       'CPPDEFINES':   ['ENABLE_OPROFILE_AGENT']
     }
   },
   'msvc': {
@@ skipping 458 matching lines @@
   },
   'verbose': {
     'values': ['on', 'off'],
     'default': 'off',
     'help': 'more output from compiler and linker'
   },
   'visibility': {
     'values': ['default', 'hidden'],
     'default': 'hidden',
     'help': 'shared library symbol visibility'
+  },
+  'armvariant': {
+    'values': ['arm', 'thumb2', 'none'],
+    'default': 'none',
+    'help': 'generate thumb2 instructions instead of arm instructions (default)'
   }
 }
 
 
 def GetOptions():
   result = Options()
   result.Add('mode', 'compilation mode (debug, release)', 'release')
   result.Add('sample', 'build sample (shell, process)', '')
   result.Add('env', 'override environment settings (NAME0:value0,NAME1:value1,...)', '')
   result.Add('importenv', 'import environment settings (NAME0,NAME1,...)', '')
@@ skipping 163 matching lines @@
   # Adjust architecture if the simulator option has been set
   if (options['simulator'] != 'none') and (options['arch'] != options['simulator']):
     if 'arch' in ARGUMENTS:
       # Print a warning if arch has explicitly been set
       print "Warning: forcing architecture to match simulator (%s)" % options['simulator']
     options['arch'] = options['simulator']
   if (options['prof'] != 'off') and (options['profilingsupport'] == 'off'):
     # Print a warning if profiling is enabled without profiling support
     print "Warning: forcing profilingsupport on when prof is on"
     options['profilingsupport'] = 'on'
+  if (options['armvariant'] == 'none' and options['arch'] == 'arm'):
+    options['armvariant'] = 'arm'
+  if (options['armvariant'] != 'none' and options['arch'] != 'arm'):
+    options['armvariant'] = 'none'
 
 
 def ParseEnvOverrides(arg, imports):
   # The environment overrides are in the format NAME0:value0,NAME1:value1,...
   # The environment imports are in the format NAME0,NAME1,...
   overrides = {}
   for var in imports.split(','):
     if var in os.environ:
       overrides[var] = os.environ[var]
   for override in arg.split(','):
@@ skipping 148 matching lines @@
 # 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()