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

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

Before it would get confused and detect above situation as 64-bit, leading to build
failures. So far we've used explicit target_arch in buildbot configuration
as a workaround, but with recipes for simplicity it'd be better
if no such workaround was needed.

BUG=none
R=maruel@google.com

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248214

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

lgtm with nits

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py
File build/detect_host_arch.py (right):

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:1: #!/usr/bin/env python
Please rename this script to make this clear this is linux, e.g.
detect_linux_host_arch.py or something like that.

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:5: 
"""Outputs 'ia32' or 'x64' representing the userland bitness."""

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:9: 
2 lines

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

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py
File build/detect_host_arch.py (right):

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:1: #!/usr/bin/env python
On 2014/01/31 14:47:47, Marc-Antoine Ruel (Google) wrote:
> Please rename this script to make this clear this is linux, e.g.
> detect_linux_host_arch.py or something like that.

Done.

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:5: 
On 2014/01/31 14:47:47, Marc-Antoine Ruel (Google) wrote:
> """Outputs 'ia32' or 'x64' representing the userland bitness."""

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

Also note it can print 'arm'.

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:9: 
On 2014/01/31 14:47:47, Marc-Antoine Ruel (Google) wrote:
> 2 lines

Done.

[M-A Ruel, 2014-01-31 16:04:57]

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py
File build/detect_host_arch.py (right):

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:5: 
On 2014/01/31 15:44:04, Paweł Hajdan Jr. wrote:
> On 2014/01/31 14:47:47, Marc-Antoine Ruel (Google) wrote:
> > """Outputs 'ia32' or 'x64' representing the userland bitness."""
> 
> There's more than bitness so I just wrote about CPU architecture.
> 
> Also note it can print 'arm'.

What about arm64?

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

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py
File build/detect_host_arch.py (right):

https://codereview.chromium.org/151143002/diff/1/build/detect_host_arch.py#ne...
build/detect_host_arch.py:5: 
On 2014/01/31 16:04:58, M-A Ruel wrote:
> What about arm64?

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.

[Paweł Hajdan Jr., 2014-01-31 17:24:01]

Committed patchset #2 manually as r248214 (presubmit successful).