Re: Contributing LLVM.org patches to gud.el

[Stephen J. Turnbull]

David Kastrup writes:

 > There is a principal basic problem that we cannot overcome with any
 > trickiness: Emacs and GCC are two separate, independent
 > applications.  _Any_ way in which we are able to combine them will
 > have a point where Emacs as an application ends and/or a point
 > where GCC ends.

No trickiness needed, because copyright doesn't work that way, at
least not in the U.S.  Emacs and GCC remain separate, true.

However, linking them in a single process implies a process of (1)
making copies of each and then (2) editing the combination to make
communication possible via function calls (and possibly access to
global data).  This copying and editing legally creates a *new* work
which *as a whole* may be *presumed to be a derivative of GCC (and
Emacs as well), according to the generally accepted "exec boundary"
doctrine.  The internal data structure representing the AST is still
covered by GCC's copyright, and by GCC's license which applies to *the
whole* because of the copying and link-editing.  The same will be true
of IDE-X and GCC.

As usual, an individual user can write code to access the necessary
GCC modules, compile and link, and run the program in the privacy of
their own home, but distributing that program must be done under the
GPL.

This application of the GPL is as solid as any.  It will successfully
prevent GCC code from being abused in a proprietary combination.