Use a faster rolling fixed Clang revision for ASan on Windows

tools/clang/scripts/update.py

Index: tools/clang/scripts/update.py
diff --git a/tools/clang/scripts/update.py b/tools/clang/scripts/update.py
index d0ba8830786cddd1699791954969c93757b118de..8f567901c887d6bd9cc7382e09694721a3974ade 100755
--- a/tools/clang/scripts/update.py
+++ b/tools/clang/scripts/update.py
@@ -16,7 +16,14 @@ import sys
 # https://code.google.com/p/chromium/wiki/UpdatingClang
 # Reverting problematic clang rolls is safe, though.
 # Note: this revision is only used for Windows. Other platforms use update.sh.
-LLVM_WIN_REVISION = 'HEAD'
+CLANG_REVISION = os.environ.get('LLVM_WIN_REVISION', '209387')

[Nico, 2014/06/18 17:56:57]

The bots should continue building HEAD, right? So I'd keep this at 'HEAD' (?)

[Reid Kleckner, 2014/06/18 19:44:33]

Yes.  They have LLVM_WIN_REVISION=HEAD in the environment, so they'll keep going
at HEAD either way.  I wrote it this way as a step towards putting everything in
update.py.  Is that not a long term goal?  I notice that update.sh has grown
since the C++11-pocalypse.

[Nico, 2014/06/18 19:54:01]

Yes, that's a long-term goal. It's strange to put a revision here if that isn't
used anywhere though (and Hans and I either forget to update this number during
rolls as it has no effect, or we remember and this is useless busywork for us),
and if you keep this 'HEAD", then the whole LLVM_WIN_REVISION bot config stuff
isn't needed.

[Reid Kleckner, 2014/06/18 20:11:26]

OK, I'll do that.

+
+# Use a more quickly rolling Clang revision for ASan on Windows.

[Nico, 2014/06/18 17:56:57]

I'd say something like

# ASan on Windows is useful enough to use it even while the clang/win is still
in bringup. Use a pinned
# revision to make it slightly more stable.

[Reid Kleckner, 2014/06/18 19:44:33]

I'll do this if we decide to go back to 'HEAD' as the default revision.

+# TODO(timurrrr): Use the standard Clang revision above when ASan on Windows has
+# stabilized.
+if (sys.platform in ['win32', 'cygwin'] and
+    re.search(r'\b(asan)=1', os.environ.get('GYP_DEFINES', ''))):
+  CLANG_REVISION = '210586'
 
 # Path constants. (All of these should be absolute paths.)
 THIS_DIR = os.path.abspath(os.path.dirname(__file__))
@@ -88,9 +95,9 @@ def CopyFile(src, dst):
 
 def Checkout(name, url, dir):
   """Checkout the SVN module at url into dir. Use name for the log message."""
-  print "Checking out %s r%s into '%s'" % (name, LLVM_WIN_REVISION, dir)
+  print "Checking out %s r%s into '%s'" % (name, CLANG_REVISION, dir)
   RunCommand(['svn', 'checkout', '--force',
-              url + '@' + LLVM_WIN_REVISION, dir], tries=2)
+              url + '@' + CLANG_REVISION, dir], tries=2)
 
 
 vs_version = None
@@ -107,8 +114,8 @@ def GetVSVersion():
 
 
 def UpdateClang():
-  print 'Updating Clang to %s...' % (LLVM_WIN_REVISION)
-  if LLVM_WIN_REVISION != 'HEAD' and ReadStampFile() == LLVM_WIN_REVISION:
+  print 'Updating Clang to %s...' % CLANG_REVISION
+  if CLANG_REVISION != 'HEAD' and ReadStampFile() == CLANG_REVISION:
     print 'Already up to date.'
     return 0
 
@@ -174,7 +181,7 @@ def UpdateClang():
       CopyFile(os.path.join(sanitizer_include_dir, f),
                aux_sanitizer_include_dir)
 
-  WriteStampFile(LLVM_WIN_REVISION)
+  WriteStampFile(CLANG_REVISION)
   print 'Clang update was successful.'
   return 0