Python 2/3 compatibility

[serge-sans-paille]

Summary

With this commit, all lld python files should be compatible with Python2 and Python3

[michaelplatings]

LGTM

[serge-sans-paille]

Thanks for the review! I've started to work on lldb python code base, and with that we should have all Python files for llvm, clang, lld and lldb compatible with Python2 and Python3.

lld/utils/benchmark.py

 #!/usr/bin/env python
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 # ==------------------------------------------------------------------------==#
 
 import os
 import glob
 import re
 import subprocess
 import json
 import datetime
 import argparse
-import urllib
-import urllib2
+try:
+    from urllib.parse import urlencode
+    from urllib.request import urlopen, Request
+except ImportError:
+    from urllib import urlencode
+    from urllib2 import urlopen, Request
+
 
 parser = argparse.ArgumentParser()
 parser.add_argument('benchmark_directory')
 parser.add_argument('--runs', type=int, default=10)
 parser.add_argument('--wrapper', default='')
 parser.add_argument('--machine', required=True)
 parser.add_argument('--revision', required=True)
 parser.add_argument('--threads', action='store_true')
ret = {
             'start_time' : end,
             'llvm_project_revision': args.revision
         },
         'tests' : tests
     }
     return json.dumps(ret, sort_keys=True, indent=4)
 
 def submitToServer(data):
-    data2 = urllib.urlencode({ 'input_data' : data }).encode('ascii')
-    urllib2.urlopen(urllib2.Request(args.url, data2))
+    data2 = urlencode({ 'input_data' : data }).encode('ascii')
+    urlopen(Request(args.url, data2))
 
 os.chdir(args.benchmark_directory)
 data = buildLntJson(getBenchmarks())
 submitToServer(data)