ARM: Default to use unaligned accesses in the simulator...

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 186 matching lines @@
       'WARNINGFLAGS': ['-Wall', '-Wno-unused', '-Werror=return-type',
                        '-Wstrict-aliasing=2'],
       'CPPPATH':      ANDROID_INCLUDES,
     },
     'arch:ia32': {
       'CPPDEFINES':   ['V8_TARGET_ARCH_IA32'],
       'CCFLAGS':      ['-m32'],
       'LINKFLAGS':    ['-m32']
     },
     'arch:arm': {
-      'CPPDEFINES':   ['V8_TARGET_ARCH_ARM']
+      'CPPDEFINES':   ['V8_TARGET_ARCH_ARM'],
+      'unalignedaccesses:on' : {
+        'CPPDEFINES' : ['CAN_USE_UNALIGNED_ACCESSES=1']
+      },
+      'unalignedaccesses:off' : {
+        'CPPDEFINES' : ['CAN_USE_UNALIGNED_ACCESSES=0']
+      }
     },
     'simulator:arm': {
-      'CCFLAGS':      ['-m32', '-DCAN_USE_UNALIGNED_ACCESSES=1'],
+      'CCFLAGS':      ['-m32'],
       'LINKFLAGS':    ['-m32']
     },
     'arch:mips': {
       'CPPDEFINES':   ['V8_TARGET_ARCH_MIPS'],
       'simulator:none': {
         'CCFLAGS':      ['-EL', '-mips32r2', '-Wa,-mips32r2', '-fno-inline'],
         'LDFLAGS':      ['-EL']
       }
     },
     'simulator:mips': {
@@ skipping 506 matching lines @@
   'msvcltcg': {
     'values': ['on', 'off'],
     'default': 'on',
     'help': 'use Microsoft Visual C++ link-time code generation'
   },
   'simulator': {
     'values': ['arm', 'mips', 'none'],
     'default': 'none',
     'help': 'build with simulator'
   },
+  'unalignedaccesses': {
+    'values': ['default', 'on', 'off'],
+    'default': 'default',
+    'help': 'set whether the ARM target supports unaligned accesses'
+  },
   'disassembler': {
     'values': ['on', 'off'],
     'default': 'off',
     'help': 'enable the disassembler to inspect generated code'
   },
   'sourcesignatures': {
     'values': ['MD5', 'timestamp'],
     'default': 'MD5',
     'help': 'set how the build system detects file changes'
   },
@@ skipping 98 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 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']:
       message = ("Unknown %s value '%s'.  Possible values are (%s)." %
           (name, env[name], ", ".join(option['values'])))
       Abort(message)
 
@@ skipping 257 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()