Output a linker map file for official builds

build/toolchain/gcc_link_wrapper.py

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Runs a linking command and optionally a strip command.
 
 This script exists to avoid using complex shell commands in
 gcc_toolchain.gni's tool("link"), in case the host running the compiler
 does not have a POSIX-like shell (e.g. Windows).
 """
 
 import argparse
 import os
 import subprocess
 import sys
 
+import wrapper_utils
+
 
 # When running on a Windows host and using a toolchain whose tools are
 # actually wrapper scripts (i.e. .bat files on Windows) rather than binary
 # executables, the "command" to run has to be prefixed with this magic.
 # The GN toolchain definitions take care of that for when GN/Ninja is
 # running the tool directly.  When that command is passed in to this
 # script, it appears as a unitary string but needs to be split up so that
 # just 'cmd' is the actual command given to Python's subprocess module.
 BAT_PREFIX = 'cmd /c call '
 
 def CommandToRun(command):
   if command[0].startswith(BAT_PREFIX):
     command = command[0].split(None, 3) + command[1:]
   return command
 
 
 def main():
   parser = argparse.ArgumentParser(description=__doc__)
   parser.add_argument('--strip',
                       help='The strip binary to run',
                       metavar='PATH')
   parser.add_argument('--unstripped-file',
-                      required=True,
                       help='Executable file produced by linking command',
                       metavar='FILE')
+  parser.add_argument('--map-file',
+                      help=('Use --Wl,-Map to generate a map file. Will be '
+                            'gzipped if extension ends with .gz'),
+                      metavar='FILE')
   parser.add_argument('--output',
                       required=True,
                       help='Final output executable file',
                       metavar='FILE')
   parser.add_argument('command', nargs='+',
                       help='Linking command')
   args = parser.parse_args()
 
   # Work-around for gold being slow-by-default. http://crbug.com/632230
   fast_env = dict(os.environ)
   fast_env['LC_ALL'] = 'C'
-  result = subprocess.call(CommandToRun(args.command), env=fast_env)
+  result = wrapper_utils.RunLinkWithOptionalMapFile(args.command, env=fast_env,
+                                                    map_file=args.map_file)
   if result != 0:
     return result
 
   # Finally, strip the linked executable (if desired).
   if args.strip:
     result = subprocess.call(CommandToRun([
         args.strip, '--strip-unneeded', '-o', args.output, args.unstripped_file
         ]))
 
   return result
 
 
 if __name__ == "__main__":
   sys.exit(main())