All our native code now gets built into Atom.framework. Atom.app and
Atom Helper.app both link against this framework. All resources other
than a couple of main-bundle-only ones (e.g., atom.icns) go into
Atom.framework.
Note that this means that there's no compile- or link-time separation
between main process code and helper process code. We could introduce a
compile-time separation by building main process and helper process code
into separate static libraries with mutually exclusive include paths, if
we want.
Atom.framework exports a single symbol: AtomMain(). Atom.app and Atom
Helper.app contain a single source file: main.cpp. main() just calls
AtomMain().
All frameworks are placed in Atom.app/Contents/Frameworks. We now link
against all frameworks using @rpath-based install names, which allows
Atom.app and Atom Helper.app to find them automatically based on their
own LD_RUNPATH_SEARCH_PATH settings. We use install_name_tool at build
time on each of our three binaries (Atom.app, Atom Helper.app,
Atom.framework) to set the install names.
By reducing duplication of code and resources between Atom.app and Atom
Helper.app (and the EH/NP copies of Atom Helper.app), this reduces the
size of the total installed Atom.app bundle from 145MB to 82MB. By
compiling .coffee and .cson files only once, clean build time drops from
114 seconds to 79 seconds on my MacBook Pro.
