Re: DragonEgg has been revived

[Simon Wright <simon@pushface.org>]

"Dan'l Miller" <optikos@verizon.net> writes:

> On Wednesday, May 23, 2018 at 2:26:49 AM UTC-5, Simon Wright wrote: 
>> Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> writes: 
>> 
>> > What I would like to see is an Ada compiler that can generate code
>> > for a wide range of targets without any GPL restrictions on the
>> > generated code.
>> 
>> Pretty sure that's called GCC. 
>
> Pretty sure that you haven't read the Object Code clauses in GPLv3 and
> the Target Code clauses and Eligible Compilation Process clauses in
> the Runtime Exception v3.1.  GPL restrictions galore on the generated
> code there in Target Code & Eligible Compilation Process (in Runtime
> Exception v3.1) interacting with Object Code, where Object Code is
> •everything• not Source Code (in GPLv3).  IR would therefore be Object
> Code due to being not Target Code and not Source Code.

You are confusing GPLv3 with the GCC Runtime Library Exception.

GPLv3 section 1 para 4 says

   The “Corresponding Source” for a work in object code form means all
   the source code needed to generate, install, and (for an executable
   work) run the object code and to modify the work, including scripts
   to control those activities. However, it does not include the work's
   System Libraries, or general-purpose tools or generally available
   free programs which are used unmodified in performing those
   activities but which are not part of the work. [...]

and it's clear that the GCC compiler itself is a 'generally available
free program'.

See also the FAQ[1]:

   [Q] Can I use GPL-covered editors such as GNU Emacs to develop
   nonfree programs? Can I use GPL-covered tools such as GCC to compile
   them?
 
   Yes, because the copyright on the editors and tools does not cover
   the code you write. Using them does not place any restrictions,
   legally, on the license you use for your code.
   
I don't think that it would contravene the GPL to modify GCC so that it
emitted an intermediate representation, provided that you convey the
source form of such modification with a compiler binary.

What could well cause trouble, and violation of the GCC Runtime Library
Exception, would be to use that modified compiler on source of an RTS
that was covered by the GCC Runtime Library Exception.

[1] https://www.gnu.org/licenses/gpl-faq.html#CanIUseGPLToolsForNF