clang update script: Verify that VERSION is correct.

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 355 matching lines @@
   return vs_version
 
 
 def CopyDiaDllTo(target_dir):
   # This script always wants to use the 64-bit msdia*.dll.
   dia_path = os.path.join(GetVSVersion().Path(), 'DIA SDK', 'bin', 'amd64')
   dia_dll = os.path.join(dia_path, DIA_DLL[GetVSVersion().ShortName()])
   CopyFile(dia_dll, target_dir)
 
 
+def VeryifyVersionOfBuiltClangMatchesVERSION():
+  """Checks that `clang --version` outputs VERSION.  If this fails, VERSION
+  in this file is out-of-date and needs to be updated (possibly in an
+  `if use_head_revision:` block in main() first)."""
+  if sys.platform == 'win32':
+    # FIXME: Parse `clang-cl /?` output for built clang's version and check

[hans, 2016/08/08 16:11:23]

Doesn't the code below work on Windows too? Regular clang.exe is still there.

[Nico, 2016/08/08 17:01:32]

That's a good point. I figured it'd be nicer to get it from the binary we're
actually shipping, but going to clang.exe is probably better than doing nothing
on Windows (though as soon as this runs on any one platform it'll do its
purpose). Let me upload a new patch...

+    pass
+  else:
+    clang = os.path.join(LLVM_BUILD_DIR, 'bin', 'clang')
+    version_out = subprocess.check_output([clang, '--version'])
+    version_out = re.match(r'clang version (\S+)', version_out).group(1)
+    if version_out != VERSION:
+      print ('unexpected clang version %s (not %s), update VERSION in update.py'
+             % (version_out, VERSION))
+      sys.exit(1)
+
+
 def UpdateClang(args):
   print 'Updating Clang to %s...' % PACKAGE_VERSION
 
   need_gold_plugin = 'LLVM_DOWNLOAD_GOLD_PLUGIN' in os.environ or (
       sys.platform.startswith('linux') and
       'buildtype=Official' in os.environ.get('GYP_DEFINES', '') and
       'branding=Chrome' in os.environ.get('GYP_DEFINES', ''))
 
   if ReadStampFile() == PACKAGE_VERSION and not args.force_local_build:
     print 'Clang is already up to date.'
@@ skipping 255 matching lines @@
   if args.tools:
     # If any Chromium tools were built, install those now.
     RunCommand(['ninja', 'cr-install'], msvc_arch='x64')
 
   if sys.platform == 'darwin':
     # See http://crbug.com/256342
     RunCommand(['strip', '-x', os.path.join(LLVM_BUILD_DIR, 'bin', 'clang')])
   elif sys.platform.startswith('linux'):
     RunCommand(['strip', os.path.join(LLVM_BUILD_DIR, 'bin', 'clang')])
 
-  # TODO(thakis): Check that `clang --version` matches VERSION.
+  VeryifyVersionOfBuiltClangMatchesVERSION()
 
   # Do an out-of-tree build of compiler-rt.
   # On Windows, this is used to get the 32-bit ASan run-time.
   # TODO(hans): Remove once the regular build above produces this.
   # On Mac and Linux, this is used to get the regular 64-bit run-time.
   # Do a clobbered build due to cmake changes.
   if os.path.isdir(COMPILER_RT_BUILD_DIR):
     RmTree(COMPILER_RT_BUILD_DIR)
   os.makedirs(COMPILER_RT_BUILD_DIR)
   os.chdir(COMPILER_RT_BUILD_DIR)
@@ skipping 223 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())