LLVM tools: get hashes from google3

BUG=None
TEST=Ran the script and returned expected results

Change-Id: I360884c2dc4088a7875e88f2115460c5aa75ab27
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1676593
Reviewed-by: George Burgess <gbiv@chromium.org>
Tested-by: Salud Lemus <saludlemus@google.com>

1 files changed, 190 insertions, 0 deletions

diff --git a/llvm_tools/get_llvm_hash.py b/llvm_tools/get_llvm_hash.py
new file mode 100755
index 00000000..98b7b749
--- /dev/null
+++ b/llvm_tools/get_llvm_hash.py
@@ -0,0 +1,190 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Returns the latest llvm version's hash."""
+
+from __future__ import print_function
+
+from pipes import quote
+import argparse
+import os
+import re
+import shutil
+import tempfile
+
+from cros_utils import command_executer
+from get_google3_llvm_version import LLVMVersion
+
+
+class LLVMHash(object):
+  """Provides two methods to retrieve a llvm hash."""
+
+  def __init__(self, log_level='none'):
+    self._ce = command_executer.GetCommandExecuter(log_level=log_level)
+    self._llvm_url = 'https://chromium.googlesource.com/external' \
+        '/github.com/llvm/llvm-project'
+
+  @staticmethod
+  def _CreateTempDirectory():
+    """Creates a temporary directory in /tmp."""
+    return tempfile.mkdtemp()
+
+  @staticmethod
+  def _DeleteTempDirectory(temp_dir):
+    """Deletes the directory created by CreateTempDirectory()."""
+    shutil.rmtree(temp_dir)
+
+  def _CloneLLVMRepo(self, temp_dir):
+    """Clones the llvm repo."""
+
+    clone_cmd = 'git clone %s %s' % (quote(self._llvm_url), quote(temp_dir))
+
+    ret, _, err = self._ce.RunCommandWOutput(clone_cmd, print_to_console=False)
+
+    if ret:  # failed to create repo
+      raise Exception('Failed to clone the llvm repo: %s' % err)
+
+  def _ParseCommitMessages(self, subdir, hash_vals, llvm_version):
+    """Parses the hashes that match the llvm version.
+
+    Args:
+      subdir: The directory where the git history resides.
+      hash_vals: All the hashes that match the llvm version.
+      llvm_version: The version to compare to in the commit message.
+
+    Returns:
+      The hash that matches the llvm version.
+
+    Raises:
+      Exception: Failed to parse a commit message.
+    """
+
+    # create regex
+    llvm_svn_pattern = re.compile(r'llvm-svn: ([0-9]+)')
+
+    # For each hash, grab the last "llvm-svn:" line
+    # and compare the llvm version of that line against
+    # the llvm version we are looking for and return
+    # that hash only if they match.
+    for cur_commit in hash_vals.splitlines():
+      cur_hash = cur_commit.split()[0]  # get hash
+
+      # cmd to output the commit body
+      find_llvm_cmd = 'git -C %s log --format=%%B -n 1 %s' % \
+          (quote(subdir), cur_hash)
+
+      ret, out, err = self._ce.RunCommandWOutput(
+          find_llvm_cmd, print_to_console=False)
+
+      if ret:  # failed to parse the commit message
+        raise Exception('Failed to parse commit message: %s' % err)
+
+      # find all "llvm-svn:" instances
+      llvm_versions = llvm_svn_pattern.findall(out)
+
+      # check the last llvm version against the llvm version we are looking for
+      if llvm_versions and int(llvm_versions[-1]) == llvm_version:
+        return cur_hash
+
+    # failed to find the commit hash
+    raise Exception('Could not find commit hash.')
+
+  def GetGitHashForVersion(self, llvm_git_dir, llvm_version):
+    """Finds the commit hash(es) of the llvm version in the git log history.
+
+    Args:
+      llvm_git_dir: The LLVM git directory.
+      llvm_version: The version to search for in the git log history.
+
+    Returns:
+      A string of the hash corresponding to the llvm version.
+
+    Raises:
+      Exception: The hash was not found in the git log history.
+    """
+
+    # base directory to search the git log history
+    subdir = os.path.join(llvm_git_dir, 'llvm')
+
+    hash_cmd = """git -C %s log --oneline --no-abbrev --grep \"llvm-svn: %d\"
+               """ % (quote(subdir), llvm_version)
+
+    ret, hash_vals, err = self._ce.RunCommandWOutput(
+        hash_cmd, print_to_console=False)
+
+    if ret:  # failed to find hash
+      raise Exception('Hash not found: %s' % err)
+
+    return self._ParseCommitMessages(subdir, hash_vals, llvm_version)
+
+  def GetLLVMHash(self, llvm_version):
+    """Retrieves the llvm hash corresponding to the llvm version passed in.
+
+    Args:
+      llvm_version: The llvm version to use as a delimiter.
+
+    Returns:
+      The hash as a string that corresponds to the llvm version.
+    """
+
+    try:
+      # create a temporary directory for the LLVM repo
+      llvm_git_dir = self._CreateTempDirectory()
+
+      # clone the "llvm-project" repo
+      self._CloneLLVMRepo(llvm_git_dir)
+
+      # find the hash
+      hash_value = self.GetGitHashForVersion(llvm_git_dir, llvm_version)
+    finally:
+      # delete temporary directory
+      self._DeleteTempDirectory(llvm_git_dir)
+
+    return hash_value
+
+  def GetGoogle3LLVMHash(self):
+    """Retrieves the google3 llvm hash."""
+
+    google3_llvm = LLVMVersion(self._ce.GetLogLevel())
+    google3_llvm_version = google3_llvm.GetGoogle3LLVMVersion()
+
+    return self.GetLLVMHash(google3_llvm_version)
+
+
+def main():
+  """Prints the google3 llvm version.
+
+  Parses the command line for the optional command line
+  arguments.
+  """
+
+  # create parser and add optional command-line arguments
+  parser = argparse.ArgumentParser(description='Finds the llvm hash.')
+  parser.add_argument(
+      '--log_level',
+      default='none',
+      choices=['none', 'quiet', 'average', 'verbose'],
+      help='the level for the logs (default: %(default)s)')
+  parser.add_argument('--llvm_version', type=int,
+                      help='the llvm version to use as the delimiter ' \
+                      '(default: uses the google3 llvm version)')
+
+  # parse command-line arguments
+  args_output = parser.parse_args()
+
+  cur_log_level = args_output.log_level  # get log level
+  cur_llvm_version = args_output.llvm_version  # get llvm version
+
+  new_llvm_hash = LLVMHash(log_level=cur_log_level)
+
+  if cur_llvm_version:  # passed in a specific llvm version
+    print(new_llvm_hash.GetLLVMHash(cur_llvm_version))
+  else:  # find the google3 llvm hash
+    print(new_llvm_hash.GetGoogle3LLVMHash())
+
+
+if __name__ == '__main__':
+  main()