Add --enable-pgo option to build clang with PGO

tools/clang/scripts/package.py

Index: tools/clang/scripts/package.py
diff --git a/tools/clang/scripts/package.py b/tools/clang/scripts/package.py
index 85840cdf008db46eb8ee47b2e25a5bb12ad1bfe3..1f2deb4925311cd59b4025078fa1e5310db77413 100755
--- a/tools/clang/scripts/package.py
+++ b/tools/clang/scripts/package.py
@@ -163,6 +163,8 @@ def main():
   parser = argparse.ArgumentParser(description='build and package clang')
   parser.add_argument('--upload', action='store_true',
                       help='Upload the target archive to Google Cloud Storage.')
+  parser.add_argument('--enable-pgo', action='store_true',
+                      help='Build clang with GO enabled.')
   args = parser.parse_args()
 
   # Check that the script is not going to upload a toolchain built from HEAD.
@@ -186,8 +188,8 @@ def main():
 
   # Check if Google Cloud Storage already has the artifacts we want to build.
   if (args.upload and GsutilArchiveExists(pdir, platform) and
-      not sys.platform.startswith('linux') or
-      GsutilArchiveExists(golddir, platform)):
+      (not sys.platform.startswith('linux') or
+      GsutilArchiveExists(golddir, platform))):
     print ('Desired toolchain revision %s is already available '
            'in Google Cloud Storage:') % expected_stamp
     print 'gs://chromium-browser-clang-staging/%s/%s.tgz' % (platform, pdir)
@@ -229,11 +231,21 @@ def main():
     opt_flags = []
     if sys.platform.startswith('linux'):
       opt_flags += ['--lto-gold-plugin']
+
+    if sys.platform != 'win32' and args.enable_pgo:
+      opt_flags += ['--enable-pgo']
+    else:
+      opt_flags += ['--bootstrap']
+
     build_cmd = [sys.executable, os.path.join(THIS_DIR, 'update.py'),
-                 '--bootstrap', '--force-local-build',
-                 '--run-tests'] + opt_flags
+                 '--force-local-build', '--run-tests'] + opt_flags
     TeeCmd(build_cmd, log)
 
+  if args.enable_pgo:
+    global LLVM_RELEASE_DIR
+    LLVM_RELEASE_DIR = os.path.join(LLVM_RELEASE_DIR, 'tools', 'clang',
+        'stage2-instrumented-bins', 'tools', 'clang', 'stage2-bins')
+
   stamp = open(STAMP_FILE).read().rstrip()
   if stamp != expected_stamp:
     print 'Actual stamp (%s) != expected stamp (%s).' % (stamp, expected_stamp)
@@ -319,7 +331,9 @@ def main():
 
   # Copy libc++ headers.
   if sys.platform == 'darwin':
-    shutil.copytree(os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'include', 'c++'),
+    install_dir = LLVM_RELEASE_DIR if args.enable_pgo else \
+        LLVM_BOOTSTRAP_INSTALL_DIR
+    shutil.copytree(os.path.join(install_dir, 'include', 'c++'),
                     os.path.join(pdir, 'include', 'c++'))
 
   # Copy buildlog over.