We already do have it, except nobody bothered to package it: DWARF4 debugging information. It's nicely structured, well-documented, easily accessed throught libdwarf; the only remaining thing to do is to package it nicely and submit to boost. It contains complete information about data layout, etc. (otherwise the debugger wouldn't know how to display your data and locate variables).

The downside is that shipping DWARF debugging info alongside of your program is not far from delivering the source code too. I guess it can be post-processed so that it only contains relevant data structures and nothing more.

Similarly, there's a COM component to access PDBs on Windows.