Reland "msvs/ninja win: Fix support for ImageHasSafeExceptionHandlers"

pylib/gyp/msvs_emulation.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This module helps emulate Visual Studio 2008 behavior on top of other
 build systems, primarily ninja.
 """
 
 import os
@@ skipping 588 matching lines @@
     ld('LinkTimeCodeGeneration',
         map={'1': '', '2': ':PGINSTRUMENT', '3': ':PGOPTIMIZE',
              '4': ':PGUPDATE'},
         prefix='/LTCG')
     ld('IgnoreDefaultLibraryNames', prefix='/NODEFAULTLIB:')
     ld('ResourceOnlyDLL', map={'true': '/NOENTRY'})
     ld('EntryPointSymbol', prefix='/ENTRY:')
     ld('Profile', map={'true': '/PROFILE'})
     ld('LargeAddressAware',
         map={'1': ':NO', '2': ''}, prefix='/LARGEADDRESSAWARE')
-    ld('ImageHasSafeExceptionHandlers', map={'true': '/SAFESEH'})
     # TODO(scottmg): This should sort of be somewhere else (not really a flag).
     ld('AdditionalDependencies', prefix='')
 
+    if self.GetArch(config) == 'x86':
+      safeseh_default = 'true'
+    else:
+      safeseh_default = None
+    ld('ImageHasSafeExceptionHandlers',
+        map={'false': ':NO', 'true': ''}, prefix='/SAFESEH',
+        default=safeseh_default)
+
     # If the base address is not specifically controlled, DYNAMICBASE should
     # be on by default.
     base_flags = filter(lambda x: 'DYNAMICBASE' in x or x == '/FIXED',
                         ldflags)
     if not base_flags:
       ldflags.append('/DYNAMICBASE')
 
     # If the NXCOMPAT flag has not been specified, default to on. Despite the
     # documentation that says this only defaults to on when the subsystem is
     # Vista or greater (which applies to the linker), the IDE defaults it on
@@ skipping 430 matching lines @@
 
   # To determine processor word size on Windows, in addition to checking
   # PROCESSOR_ARCHITECTURE (which reflects the word size of the current
   # process), it is also necessary to check PROCESSOR_ARCHITEW6432 (which
   # contains the actual word size of the system when running thru WOW64).
   if ('64' in os.environ.get('PROCESSOR_ARCHITECTURE', '') or
       '64' in os.environ.get('PROCESSOR_ARCHITEW6432', '')):
     default_variables['MSVS_OS_BITS'] = 64
   else:
     default_variables['MSVS_OS_BITS'] = 32