Add a tool to download Chromium's prebuilt clang.

See tools/clang/scripts/update.sh. This'll be used to run ASan on the bots.

BUG=469928

Change-Id: I6b5093c2db21ad4ed742852944e77a6b32e29e29
Reviewed-on: https://boringssl-review.googlesource.com/4402
Reviewed-by: Adam Langley <agl@google.com>

util/bot/DEPS

@@ -85,6 +85,13 @@ hooks = [
                 'update',
     ],
   },
+  {
+    'name': 'clang',
+    'pattern': '.',
+    'action': [ 'python',
+                'boringssl/util/bot/update_clang.py',
+    ],
+  },
   # TODO(davidben): Only extract archives when they've changed. Extracting perl
   # on Windows is a significant part of the cycle time.
   {

util/bot/update_clang.py

@@ -0,0 +1,71 @@
+# Copyright (c) 2015, Google Inc.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+import os.path
+import shutil
+import sys
+import tarfile
+import tempfile
+import urllib
+
+# CLANG_REVISION and CLANG_SUB_REVISION determine the build of clang
+# to use. These should be synced with tools/clang/scripts/update.sh in
+# Chromium.
+CLANG_REVISION = "233105"
+CLANG_SUB_REVISION = "1"
+
+PACKAGE_VERSION = "%s-%s" % (CLANG_REVISION, CLANG_SUB_REVISION)
+LLVM_BUILD_DIR = os.path.join(os.path.dirname(__file__), "llvm-build")
+STAMP_FILE = os.path.join(LLVM_BUILD_DIR, "cr_build_revision")
+
+CDS_URL = "https://commondatastorage.googleapis.com/chromium-browser-clang"
+
+def DownloadFile(url, path):
+  """DownloadFile fetches |url| to |path|."""
+  last_progress = [0]
+  def report(a, b, c):
+    progress = int(a * b * 100.0 / c)
+    if progress != last_progress[0]:
+      print >> sys.stderr, "Downloading... %d%%" % progress
+      last_progress[0] = progress
+  urllib.urlretrieve(url, path, reporthook=report)
+
+def main(args):
+  # For now, only download clang on Linux.
+  if not sys.platform.startswith("linux"):
+    return 0
+
+  if os.path.exists(STAMP_FILE):
+    with open(STAMP_FILE) as f:
+      if f.read().strip() == PACKAGE_VERSION:
+        print >> sys.stderr, "Clang already at %s" % (PACKAGE_VERSION,)
+        return 0
+
+  if os.path.exists(LLVM_BUILD_DIR):
+    shutil.rmtree(LLVM_BUILD_DIR)
+
+  print >> sys.stderr, "Downloading Clang %s" % (PACKAGE_VERSION,)
+  cds_full_url = "%s/Linux_x64/clang-%s.tgz" % (CDS_URL, PACKAGE_VERSION)
+  with tempfile.NamedTemporaryFile() as temp:
+    DownloadFile(cds_full_url, temp.name)
+    with tarfile.open(temp.name, "r:gz") as tar_file:
+      tar_file.extractall(LLVM_BUILD_DIR)
+
+  with open(STAMP_FILE, "wb") as stamp_file:
+    stamp_file.write(PACKAGE_VERSION)
+
+  return 0
+
+if __name__ == "__main__":
+  sys.exit(main(sys.argv[1:]))