--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/gcc-changelog/git_update_version.py	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+#
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation; either version 3, or (at your option) any later
+# version.
+#
+# GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.  */
+
+import argparse
+import datetime
+import os
+
+from git import Repo
+
+from git_repository import parse_git_revisions
+
+current_timestamp = datetime.datetime.now().strftime('%Y%m%d\n')
+
+
+def read_timestamp(path):
+    return open(path).read()
+
+
+def prepend_to_changelog_files(repo, folder, git_commit):
+    if not git_commit.success:
+        for error in git_commit.errors:
+            print(error)
+        raise AssertionError()
+    for entry, output in git_commit.to_changelog_entries(use_commit_ts=True):
+        full_path = os.path.join(folder, entry, 'ChangeLog')
+        print('writting to %s' % full_path)
+        if os.path.exists(full_path):
+            content = open(full_path).read()
+        else:
+            content = ''
+        with open(full_path, 'w+') as f:
+            f.write(output)
+            if content:
+                f.write('\n\n')
+                f.write(content)
+        repo.git.add(full_path)
+
+
+active_refs = ['master', 'releases/gcc-8', 'releases/gcc-9', 'releases/gcc-10']
+
+parser = argparse.ArgumentParser(description='Update DATESTAMP and generate '
+                                 'ChangeLog entries')
+parser.add_argument('-g', '--git-path', default='.',
+                    help='Path to git repository')
+args = parser.parse_args()
+
+repo = Repo(args.git_path)
+origin = repo.remotes['origin']
+
+for ref in origin.refs:
+    assert ref.name.startswith('origin/')
+    name = ref.name[len('origin/'):]
+    if name in active_refs:
+        if name in repo.branches:
+            branch = repo.branches[name]
+        else:
+            branch = repo.create_head(name, ref).set_tracking_branch(ref)
+        print('=== Working on: %s ===' % branch, flush=True)
+        origin.pull(rebase=True)
+        branch.checkout()
+        print('branch pulled and checked out')
+        assert not repo.index.diff(None)
+        commit = branch.commit
+        commit_count = 1
+        while commit:
+            if (commit.author.email == 'gccadmin@gcc.gnu.org'
+                    and commit.message.strip() == 'Daily bump.'):
+                break
+            commit = commit.parents[0]
+            commit_count += 1
+
+        print('%d revisions since last Daily bump' % commit_count)
+        datestamp_path = os.path.join(args.git_path, 'gcc/DATESTAMP')
+        if read_timestamp(datestamp_path) != current_timestamp:
+            print('DATESTAMP will be changed:')
+            commits = parse_git_revisions(args.git_path, '%s..HEAD'
+                                          % commit.hexsha)
+            for git_commit in reversed(commits):
+                prepend_to_changelog_files(repo, args.git_path, git_commit)
+            # update timestamp
+            with open(datestamp_path, 'w+') as f:
+                f.write(current_timestamp)
+            repo.git.add(datestamp_path)
+            repo.index.commit('Daily bump.')
+            # TODO: push the repository
+            # repo.git.push('origin', branch)
+        else:
+            print('DATESTAMP unchanged')
+        print('branch is done\n', flush=True)