[Mac/GN] Add a new linker_driver.py option to save unstripped linker output.

build/toolchain/mac/linker_driver.py

 #!/usr/bin/env python
 
 # Copyright 2016 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.
 
 import os
 import os.path
 import shutil
 import subprocess
@@ skipping 13 matching lines @@
 # removal of the special driver arguments, described below). Then the driver
 # performs additional actions, based on these arguments:
 #
 #   -Wcrl,dsym,<dsym_path_prefix>
 #       After invoking the linker, this will run `dsymutil` on the linker's
 #       output, producing a dSYM bundle, stored at dsym_path_prefix. As an
 #       example, if the linker driver were invoked with:
 #         "... -o out/gn/obj/foo/libbar.dylib ... -Wcrl,dsym,out/gn ..."
 #       The resulting dSYM would be out/gn/libbar.dylib.dSYM/.
 #
+#   -Wcrl,unstripped,<unstripped_path_prefix>
+#       After invoking the linker, and before strip, this will save a copy of
+#       the unstripped linker output in the directory unstripped_path_prefix.
+#
 #   -Wcrl,strip,<strip_arguments>
 #       After invoking the linker, and optionally dsymutil, this will run
 #       the strip command on the linker's output. strip_arguments are
 #       comma-separated arguments to be passed to the strip command.
 
 def Main(args):
   """Main function for the linker driver. Separates out the arguments for
   the main compiler driver and the linker driver, then invokes all the
   required tools.
 
@@ skipping 84 matching lines @@
   linker_out = _FindLinkerOutput(full_args)
   (head, tail) = os.path.split(linker_out)
   dsym_out = os.path.join(dsym_path_prefix, tail + '.dSYM')
 
   # Remove old dSYMs before invoking dsymutil.
   _RemovePath(dsym_out)
   subprocess.check_call(['xcrun', 'dsymutil', '-o', dsym_out, linker_out])
   return [dsym_out]
 
 
+def RunSaveUnstripped(unstripped_path_prefix, full_args):
+  """Linker driver action for -Wcrl,unstripped,<unstripped_path_prefix>. Copies
+  the linker output to |unstripped_path_prefix| before stripping.
+
+  Args:
+    unstripped_path_prefix: string, The path at which the unstripped output
+        should be located.
+    full_args: list of string, Full argument list for the linker driver.
+
+  Returns:
+    list of string, Build step outputs.
+  """
+  if not len(unstripped_path_prefix):
+    raise ValueError('Unspecified unstripped output file')
+
+  linker_out = _FindLinkerOutput(full_args)
+  (head, tail) = os.path.split(linker_out)
+  unstripped_out = os.path.join(unstripped_path_prefix, tail + '.unstripped')
+
+  shutil.copyfile(linker_out, unstripped_out)
+  return [unstripped_out]
+
+
 def RunStrip(strip_args_string, full_args):
   """Linker driver action for -Wcrl,strip,<strip_arguments>.
 
   Args:
       strip_args_string: string, Comma-separated arguments for `strip`.
       full_args: list of string, Full arguments for the linker driver.
 
   Returns:
       list of string, Build step outputs.
   """
@@ skipping 23 matching lines @@
 
 
 _LINKER_DRIVER_ARG_PREFIX = '-Wcrl,'
 
 """List of linker driver actions. The sort order of this list affects the
 order in which the actions are invoked. The first item in the tuple is the
 argument's -Wcrl,<sub_argument> and the second is the function to invoke.
 """
 _LINKER_DRIVER_ACTIONS = [
     ('dsym,', RunDsymUtil),
+    ('unstripped,', RunSaveUnstripped),
     ('strip,', RunStrip),
 ]
 
 
 if __name__ == '__main__':
   Main(sys.argv)
   sys.exit(0)