regno_reg_rtx and related macros

[Richard Kenner]

    These debugging problems are the same one sees in any object-oriented
    environment; all Bernd has done is packaged stuff up in objects.

No, not really.  In an OO environment, the debugger knows how to
display objects when the user cuts and pastes the same expression on
his screen.  But here they are macros, so GDB can't do it.  That's the
major difference.

The whole point behind OO is information hiding, but that hiding needs to
be known in order to display values in the debugger using the present scheme.