Compile frame analyzer for the host machine on perf tests.

Bug: webrtc:9665
Change-Id: I05c01ee4bef0995556b1a679498b3d9132de7c26
Reviewed-on: https://webrtc-review.googlesource.com/100360
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Oleh Prypin <oprypin@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24756}

tools_webrtc/executable_host_build.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env/python
+
+# Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+"""
+This script builds a GN executable targeting the host machine.
+
+It is useful, for example, for mobile devices performance testing where
+it makes sense to build WebRTC for a mobile platform (e.g. Android) but
+part of the test is performed on the host machine (e.g. running an
+executable to analyze a video downloaded from a device).
+
+The script has only one (mandatory) option: --executable_name, which is
+the output name of the GN executable. For example, if you have the
+following executable in your out folder:
+
+  out/Debug/random_exec
+
+You will be able to compile the same executable targeting your host machine
+by running:
+
+  $ python tools_webrtc/executable_host_build.py --executable_name random_exec
+
+The generated executable will have the same name as the input executable with
+suffix '_host'.
+
+This script should not be used standalone but from GN, through an action:
+
+  action("random_exec_host") {
+    script = "//tools_webrtc/executable_host_build.py"
+    outputs = [
+      "${root_out_dir}/random_exec_host",
+    ]
+    args = [
+      "--executable_name",
+      "random_exec",
+    ]
+  }
+
+The executable for the host machine will be generated in the GN out directory
+(e.g. out/Debug in the previous example).
+"""
+
+from contextlib import contextmanager
+
+import argparse
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+SRC_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, os.pardir))
+sys.path.append(os.path.join(SRC_DIR, 'build'))
+import find_depot_tools
+
+
+def _ParseArgs():
+  desc = 'Generates a GN executable targeting the host machine.'
+  parser = argparse.ArgumentParser(description=desc)
+  parser.add_argument('--executable_name',
+                      required=True,
+                      help='Name of the executable to build')
+  args = parser.parse_args()
+  return args
+
+
+@contextmanager
+def HostBuildDir():
+  temp_dir = tempfile.mkdtemp()
+  try:
+    yield temp_dir
+  finally:
+    shutil.rmtree(temp_dir)
+
+
+def _RunCommand(argv, cwd=SRC_DIR, **kwargs):
+  with open(os.devnull, 'w') as devnull:
+    subprocess.check_call(argv, cwd=cwd, stdout=devnull, **kwargs)
+
+
+def DepotToolPath(*args):
+  return os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, *args)
+
+
+if __name__ == '__main__':
+  ARGS = _ParseArgs()
+  EXECUTABLE_TO_BUILD = ARGS.executable_name
+  EXECUTABLE_FINAL_NAME = ARGS.executable_name + '_host'
+  with HostBuildDir() as build_dir:
+    _RunCommand([sys.executable, DepotToolPath('gn.py'), 'gen', build_dir])
+    _RunCommand([DepotToolPath('ninja'), '-C', build_dir, EXECUTABLE_TO_BUILD])
+    shutil.copy(os.path.join(build_dir, EXECUTABLE_TO_BUILD),
+                EXECUTABLE_FINAL_NAME)