Make gyp autodetection of host_arch work for 64-bit kernel and 32-bit userland

build/detect_host_arch.py

Index: build/detect_host_arch.py
diff --git a/build/detect_host_arch.py b/build/detect_host_arch.py
new file mode 100755
index 0000000000000000000000000000000000000000..754a12e3f4a8c938e70941cf5c5c19671861d7eb
--- /dev/null
+++ b/build/detect_host_arch.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python

[Marc-Antoine Ruel (Google), 2014/01/31 14:47:47]

Please rename this script to make this clear this is linux, e.g.
detect_linux_host_arch.py or something like that.

[Paweł Hajdan Jr., 2014/01/31 15:44:04]

Done.

+# Copyright 2014 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.
+

[Marc-Antoine Ruel (Google), 2014/01/31 14:47:47]

"""Outputs 'ia32' or 'x64' representing the userland bitness."""

[Paweł Hajdan Jr., 2014/01/31 15:44:04]

There's more than bitness so I just wrote about CPU architecture.

Also note it can print 'arm'.

[M-A Ruel, 2014/01/31 16:04:58]

What about arm64?

[Paweł Hajdan Jr., 2014/01/31 16:08:35]

It just mirrors the previous logic from gyp - anyone building natively on arm is
free to fix things as needed.

I don't think gyp recognizes arm64, and I know there are people building
natively on arm, see e.g.
http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/www-client/chromium/c...

Anyone is free to fix this script of course for arm or anything else - I'd just
prefer not to do that for platform I don't build on.

+import platform
+import re
+import sys
+

[Marc-Antoine Ruel (Google), 2014/01/31 14:47:47]

2 lines

[Paweł Hajdan Jr., 2014/01/31 15:44:04]

Done.

+def main():
+  host_arch = platform.machine()
+
+  # Convert machine type to format recognized by gyp.
+  if re.match(r'i.86', host_arch) or host_arch == 'i86pc':
+    host_arch = 'ia32'
+  elif host_arch in ['x86_64', 'amd64']:
+    host_arch = 'x64'
+  elif host_arch.startswith('arm'):
+    host_arch = 'arm'
+
+  # platform.machine is based on running kernel. It's possible to use 64-bit
+  # kernel with 32-bit userland, e.g. to give linker slightly more memory.
+  # Distinguish between different userland bitness by querying
+  # the python binary.
+  if host_arch == 'x64' and platform.architecture()[0] == '32bit':
+    host_arch = 'ia32'
+
+  print host_arch
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(main())