Re: How to challenge a GCC patch?

[Arnaud Charlet <charlet@adacore.com>]

On Monday, September 27, 2021 at 1:23:39 PM UTC+2, Stéphane Rivière wrote:
> Le 27/09/2021 à 12:06, J-P. Rosen a écrit : 
> > AdaCore has introduced a patch in FSF GCC to remove ASIS support.
> This is all the more surprising since it seems to me that ASIS is still 
> in GNAT Pro. What a lack of fairness.

We have removed ASIS support first in our own trunk of GNAT, and then 6 months later we have removed it from the GCC FSF trunk, so talking about lack of fairness is, well, unfair.

Why? Because ASIS is no longer maintained as an internal standard and hasn't evolved beyond Ada 95 because there was not enough support in the community and among vendors, so we've ended up maintaining it on our own for many years, which lately has become too large a burden. In addition, maintaining ASIS tree generation in GNAT has been also a challenge and a resource drain because each time we make a change in the GNAT front-end, this may break ASIS and we may have to make difficult investigation and changes and sometimes almost impossible changes because there are conflicts between the need of a code generator (GNAT for GCC or LLVM) and the need of an Ada analysis library (ASIS).

So we've decided to address this burden by moving tree generation for ASIS in a separate branch, so that this maintenance burden on GCC trunk would disappear.

This has been done both in AdaCore's tree where ASIS now resides on a separate branch, and in GCC FSF where the tree generation is available in GCC 10.x and works well here, and is available for the community to contribute and maintain for as long as needed.

Arno