Support for ARM NaCl untrusted runtime build.

build/download_nacl_toolchains.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Shim to run nacl toolchain download script only if there is a nacl dir."""
 
 import os
 import sys
 
 
 def Main(args):
   # Exit early if disable_nacl=1.
   if 'disable_nacl=1' in os.environ.get('GYP_DEFINES', ''):
     return 0
+
   script_dir = os.path.dirname(os.path.abspath(__file__))
   src_dir = os.path.dirname(script_dir)
   nacl_dir = os.path.join(src_dir, 'native_client')
   nacl_build_dir = os.path.join(nacl_dir, 'build')
   download_script = os.path.join(nacl_build_dir, 'download_toolchains.py')
   if not os.path.exists(download_script):
     print "Can't find '%s'" % download_script
     print 'Presumably you are intentionally building without NativeClient.'
     print 'Skipping NativeClient toolchain download.'
     sys.exit(0)
   sys.path.insert(0, nacl_build_dir)
   import download_toolchains
 
   # TODO (robertm): Finish getting PNaCl ready for prime time.
   # BUG:
   # We remove this --optional-pnacl argument, and instead replace it with
   # --no-pnacl for most cases.  However, if the bot name is the pnacl_sdk
   # bot then we will go ahead and download it.  This prevents increasing the
   # gclient sync time for developers, or standard Chrome bots.
   if '--optional-pnacl' in args:
     args.remove('--optional-pnacl')
+    # By default we don't use PNaCl toolchain yet, unless on ARM, where
+    # there is no other toolchain to build untrusted code at the moment.
+    # So analyze if we're building for ARM, or on SDK buildbot.
+    use_pnacl = False
+    if 'target_arch=arm' in os.environ.get('GYP_DEFINES', ''):

[Mark Seaborn, 2012/03/28 14:59:24]

Hmm, this is a horrible hack that doesn't work if one wants to supply gyp
defines via another means.  What would it mean to do this properly?  Please put
a TODO in at least.

Is there a Chromium trybot that covers this?  I don't see any trybot results for
your change?  (To be fair, you were probably waiting on the NaCl side change
before you can do try runs.)

[Nikolay, 2012/03/29 14:36:07]

Agree, but fortunately this hack also matches the way CrOs build system works,
so for most important ARM/NaCl case and for standard way developers configure
their build we're OK.
For cross-compilation case, it's rather hard to figure out intention of
developer, the only other (somewhat) reasonable approach is to perform smth like
$CC --version | grep arm.
Will add TODO.

Regarding trybots - CrOs bots will build NaCl by default, once this whole effort
will be over.

On 2012/03/28 14:59:24, Mark Seaborn wrote:

[davidjames, 2012/03/29 17:30:24]

What changes need to be made to the CrOS ebuild to make the gyp files clean?
Please make those changes and upload them. You don't need to be afraid of
patching the chrome ebuild as it is easy :)

[Nikolay, 2012/03/30 14:02:11]

See https://chromiumcodereview.appspot.com/9923012/

On 2012/03/29 17:30:24, davidjames wrote:

[Nikolay, 2012/04/02 08:32:13]

Was told that need to use gerrit here, so please see
https://gerrit.chromium.org/gerrit/#change,19355

On 2012/03/30 14:02:11, olonho wrote:

+      use_pnacl = True
     buildbot_name = os.environ.get('BUILDBOT_BUILDERNAME', '')
     if buildbot_name.find('pnacl') >= 0 and  buildbot_name.find('sdk') >= 0:
+      use_pnacl = True
+    if use_pnacl:
       print '\n*** DOWNLOADING PNACL TOOLCHAIN ***\n'
     else:
       args.append('--no-pnacl')
 
   download_toolchains.Main(args)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main(sys.argv[1:]))
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