[Info-vax] Ada x86 (was Rdb/x86)

[gérard Calliet]

Le 30/11/2020 à 19:12, John Dallman a écrit :
> In article <50eae468-5877-48c9-9cd9-772c9563680bn at googlegroups.com>,
> xyzzy1959 at gmail.com (John Reagan) wrote:
> 
>> Our "GEM to LLVM" converter is not sufficient for our ancient DEC 
>> Ada which was never on Itanium, just Alpha. What I have said is 
>> that I personally think that an Ada solution would be helpful to 
>> many customers.
> 
> Presumably, porting GNAT (Gnu Ada) may be possible in principle, but
> would be a lot of work? There's work towards porting it to Itanium at
> https://github.com/AdaLabs/gnat-vms
> 
> John 
> 
We have done this (cross-)built 4 years ago (we: adalabs, pia-sofer(me,
www.pia-sofer.fr)) with some friendly help of members of Adacore who
knew perfectly what was done for gcc/vms on Ada. We used a set of
headers from 8.4* itanium.

It is a little bit old now. For example we need a Linux wheezy
environment, wich is now archived. It is based en gcc 4.3.7

I (pia-sofer and a more community-oriented link here: www.vmsadaall.org)
am working now to go ahead.

First it seems possible to upgrade to gcc 4.9 which is the last version
for which adacore published on FSF. In the same time I am working to get
with the Ada compiler the C and C++ (gcc) compilers. It seems it is
possible. Eveything only on Itanium.

Second, with a little more effort, I'll try upgrades to more recent gcc
versions. I have to bring back the VMS specificities Adacore had taken
off. And pray that gcc improvments will not imply too much work on VMS.
This second step is a little bit "just for fun", not a priority. I would
like to understand what have been the technical difficulties Adacore
encountered to get off, even if I think the problem was mostly
commercial, and of bad relations with HP.

To get Ada on VMS/x86 the better way seems to play with the Adacore
work-in-progress of gnat/llvm (https://github.com/AdaCore/gnat-llvm). It
is something up-to-date (more than DragonEgg). I'm just beginning to
explore their work today.

For sure their use of llvm has to be tranformed to plug it on
VSI/llvm/x86. And I don't know how VSI could accept to communicate on
their llvm internals (on linux, itanium and x86). On my side I'm totally
open :)

Everyone is welcomed on a community effort. And I do think, because of
the nature (open source) and complexity (huge) of gcc, Ada and llvm that
only a community effort  could do the job. I'll initiate soon a blog on
www.vmsadaall.org .