Clang toolchain: checkout LLD on all platforms but Darwin.

tools/clang/scripts/update.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.
 
 """This script is used to download prebuilt clang binaries.
 
 It is also used by package.py to build the prebuilt clang binaries."""
 
 import argparse
@@ skipping 439 matching lines @@
 
   DownloadHostGcc(args)
   AddSvnToPathOnWin()
   AddCMakeToPath()
   AddGnuWinToPath()
 
   DeleteChromeToolsShim()
 
   Checkout('LLVM', LLVM_REPO_URL + '/llvm/trunk', LLVM_DIR)
   Checkout('Clang', LLVM_REPO_URL + '/cfe/trunk', CLANG_DIR)
-  if sys.platform == 'win32' or use_head_revision:

[Nico, 2016/12/13 20:02:23]

Do we still need use_head_revision here now that we do this on Linux? I guess
the Mac tot bots currently build LLD but they probably shouldn't anyway.
use_head_revision is probably here 'cause you added it for the lld tot bot? (I
don't remember)

[krasin1, 2016/12/13 20:08:19]

It was Peter who set up the LLD ToT bot, but you're right about the intention. I
can invert the condition to sys.platform != 'darwin'. Would that be better?

[Nico, 2016/12/13 20:12:55]

I mean I think we can remove the use_head_revision bit now. I don't care if we
do `platform == win || platform == linux` or `platform != darwin`, those are
both fine.

(If we do do remove use_head_revision, we should probably have an else: branch
that deletes lld if it's there, to clean up the checkouts on the mac tot bots,
at least for a short while)

+  if (sys.platform == 'win32' or sys.platform.startswith('linux') or
+      use_head_revision):
     Checkout('LLD', LLVM_REPO_URL + '/lld/trunk', LLD_DIR)
   Checkout('compiler-rt', LLVM_REPO_URL + '/compiler-rt/trunk', COMPILER_RT_DIR)
   if sys.platform == 'darwin':
     # clang needs a libc++ checkout, else -stdlib=libc++ won't find includes
     # (i.e. this is needed for bootstrap builds).
     Checkout('libcxx', LLVM_REPO_URL + '/libcxx/trunk', LIBCXX_DIR)
     # We used to check out libcxxabi on OS X; we no longer need that.
     if os.path.exists(LIBCXXABI_DIR):
       RmTree(LIBCXXABI_DIR)
 
@@ skipping 424 matching lines @@
     args.force_local_build = True
     if 'OS=android' not in os.environ.get('GYP_DEFINES', ''):
       # Only build the Android ASan rt on ToT bots when targetting Android.
       args.with_android = False
 
   return UpdateClang(args)
 
 
 if __name__ == '__main__':
   sys.exit(main())