For building v8 using gn on aix_ppc64, linux_s390x and linux_ppc64.

build/toolchain/gcc_ar_wrapper.py

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Runs the 'ar' command after removing its output file first.
 
 This script is invoked like:
   python gcc_ar_wrapper.py --ar=$AR --output=$OUT $OP $INPUTS
 to do the equivalent of:
@@ skipping 22 matching lines @@
                       help='Load plugin')
   parser.add_argument('--resource-whitelist',
                       help='Merge all resource whitelists into a single file.',
                       metavar='PATH')
   parser.add_argument('operation',
                       help='Operation on the archive')
   parser.add_argument('inputs', nargs='+',
                       help='Input files')
   args = parser.parse_args()
 
-  if args.resource_whitelist:
-    whitelist_candidates = wrapper_utils.ResolveRspLinks(args.inputs)
-    wrapper_utils.CombineResourceWhitelists(
-        whitelist_candidates, args.resource_whitelist)
+  # Specifies the type of object file ar should examine.
+  # The ar on linux ignores this option.
+  object_mode = []
+  if sys.platform.startswith('aix'):
+    # The @file feature is not avaliable on ar for AIX.
+    # For linux (and other posix like systems), the @file_name
+    # option reads the contents of file_name as command line arguments.
+    # For AIX we must parse these (rsp files) manually.
+    # Read rspfile.
+    args.inputs  = wrapper_utils.ResolveRspLinks(args.inputs)
+    object_mode = ['-X64']
+  else:
+    if args.resource_whitelist:
+      whitelist_candidates = wrapper_utils.ResolveRspLinks(args.inputs)
+      wrapper_utils.CombineResourceWhitelists(
+          whitelist_candidates, args.resource_whitelist)
 
-  command = [args.ar, args.operation]
+  command = [args.ar] + object_mode + [args.operation]
   if args.plugin is not None:
     command += ['--plugin', args.plugin]
   command.append(args.output)
   command += args.inputs
 
   # Remove the output file first.
   try:
     os.remove(args.output)
   except OSError as e:
     if e.errno != os.errno.ENOENT:
       raise
 
   # Now just run the ar command.
   return subprocess.call(wrapper_utils.CommandToRun(command))
 
 
 if __name__ == "__main__":
   sys.exit(main())