Add XCode debugging doc

Author: nitsakh

docs/development/debugging-instructions-macos-xcode.md

@@ -0,0 +1,52 @@
+## Debugging with XCode
+
+### Build Debug Electron with Release libchromiumcontent
+You can create a debug build of electron by following [build instructions for macOS](build-instructions-osx.md).
+The bootstrap process will download Release version of libchromiumcontent by default,
+so you will not be able to step through the chromium source.
+
+### Build Debug Electron with Debug libchromiumcontent
+If you want to debug and step through libchromiumcontent, you will have to run the 
+bootsrap script with the `--build_debug_libcc` argument.
+
+```sh
+$ cd electron
+$ ./script/bootstrap.py -v --build_debug_libcc
+```
+This can take a significant amount of time depending on build machine as it has to
+build all of the libchromium source.
+
+Once, the lib is built, create a symlink to the built directory under download
+
+`ln -s vendor/libchromiumcontent/dist/main/shared_library vendor/download/libchromiumcontent/shared_library`
+
+Electron debug builds will use this shared library to link against.
+
+```sh
+$ ./script/build.py -c D --libcc
+```
+This will build debug electron with debug version of libchromiumcontent.
+
+### Generate xcode project for debugging sources (cannot build code from xcode)
+Run the update script with the --xcode argument.
+```sh
+$ ./script/update.py --xcode
+```
+This will generate the electron.ninjs.xcworkspace. You will have to open this workspace
+to set breakpoints and inspect.
+
+### Debugging and breakpoints
+
+Launch electron app after build.
+You can now open the xcode workspace created above and attach to the electron process
+through the Debug > Attach To Process > Electron debug menu. [Note: If you want to debug
+the renderer process, you need to attach to the Electron Helper as well.]
+
+You can now set breakpoints in any of the indexed files. However, you will not be able
+to set breakpoints directly in the chromium source.
+To set break points in the chromium source, you can choose Debug > Breakpoints > Create
+Symbolic Breakpoint and set any function name as the symbol. This will set the breakpoint
+for all functions with that name, from all the classes if there are more than one.
+You can also do this step of setting break points prior to attaching the debugger,
+however, actual breakpoints for symbolic breakpoint functions may not show up until the
+debugger is attached to the app.

docs/development/debugging-instructions-macos.md

@@ -5,6 +5,8 @@ by your JavaScript application, but instead by Electron itself, debugging can
 be a little bit tricky, especially for developers not used to native/C++
 debugging. However, using lldb, and the Electron source code, it is fairly easy
 to enable step-through debugging with breakpoints inside Electron's source code.
+You can also use [XCode for debugging](debugging-instructions-macos-xcode.md) if
+you prefer a graphical interface.
 
 ## Requirements
 

script/update.py

@@ -28,8 +28,11 @@ def parse_args():
   parser = argparse.ArgumentParser(description='Update build configurations')
   parser.add_argument('--defines', default='',
                       help='The build variables passed to gyp')
-  parser.add_argument('--msvs', action='store_true',
+  group = parser.add_mutually_exclusive_group(required=False)
+  group.add_argument('--msvs', action='store_true',
                       help='Generate Visual Studio project')
+  group.add_argument('--xcode', action='store_true',
+                      help='Generate XCode project')
   return parser.parse_args()
 
 
@@ -91,6 +94,8 @@ def run_gyp(target_arch, component):
   generator = 'ninja'
   if args.msvs:
     generator = 'msvs-ninja'
+  elif args.xcode:
+    generator = 'xcode-ninja'
 
   return subprocess.call([python, gyp, '-f', generator, '--depth', '.',
                           'electron.gyp', '-Icommon.gypi'] + defines, env=env)