Re: Thoughts on AdaCore maintaining GCC-incompatible GNAT sources

["Randy Brukardt" <randy@rrsoftware.com>]

"Stephen Leake" <stephen_leake@stephe-leake.org> wrote in message 
news:82k4hyq328.fsf@stephe-leake.org...
> deadlyhead <deadlyhead@gmail.com> writes:
>
>> I actually can't see any downside to AdaCore developing on a GCC
>> branch.
>
> It would take them more time than they currently spend developing Ada.
> Somebody has to pay for that time.

I second this suggestion. Indeed, I find it amazing that anyone can build 
large software like a compiler even when they have all of the source.

Case in point, I recently recompiled Janus/Ada with the current Janus/Ada 
compiler (rather than the older baseline compiler). That ended up taking 
parts of 8 days! And that was with nothing expecting needing change in 
either the building setup or compiler source.

But all manner of bugs showed up, both in the current Janus/Ada compiler 
(which is amazing to me, given that I've been using that version for all of 
my work other than the compiler for 7 or so years) and in the compiler 
itself (due to improved checking of Ada rules in the latest compiler). Plus 
a number of mysterious problems, one of which appeared only once and hasn't 
reappeared since, and another which turned out to be caused by mistakenly 
running the wrong compiler in the testing directory (there was some missing 
version checking [now fixed], and apparently the files are getting laid out 
differently, so the older compiler scrambled the project files).

Anyway, I'd consider it a miracle if anyone could compile something as large 
as the GNAT sources with anything other than the exact setup they were 
originally created with. There is just too much chance of running across 
some obscure bug otherwise.

The less stable the development environment, the harder it would be to work 
on the compiler. And that costs time, which of course costs money (at least 
for a commercial company like AdaCore).

                                       Randy.