Re: Inspirels Ada on cortex tutorial linker issue

[AdaMagica <christ-usch.grein@t-online.de>]

Am Mittwoch, 31. August 2016 14:42:59 UTC+2 schrieb Maciej Sobczak:
> On Monday, August 29, 2016 at 11:51:36 PM UTC+2, riea...@comcast.net wrote:
> > All in all, much, much better than other languages where moving an
> > application from one compiler to another for the same target can take weeks.
>
> Sorry, but this argument is as wrong as it is frequently repeated.
> If you move Ada to another compiler, you can be sure that your gnatmake will
> not work anymore. And then it will take weeks to configure the new tool.
>
> Similarly, I can see people arguing that Ada is more portable than "other
> languages" (meaning C), because they never move outside of GNAT. If you don't
> change the compiler, then Ada and "other languages" are similarly portable.
> There is nothing magic in Ada, it is a single toolchain that people are
> attached to (for whatever reason), that makes their code kind of portable or
> stable.

Well, I can't comment on C(++). But:

I re-hosted several million lines of airborne embedded Ada code to different hardware (big endian to little endian) with compilers from different manufacturers (Ada 83 to Ada 95/2005) for use in full scale flight simulators. And to my big surprise, only very few pieces of code had to be touched.

GNAT's project files were easily written to work with the original code distribution over more than a dozen subsystem directory trees. It didn't take weeks; of course I had to learn about project files, but then it was matter of a few hours.

Biggest problems were:
- BE to LE
- original code not fully compliant to Ada RM (e.g. with Unchecked_Conversion)
- elaboration circularities arising because of code changes for simulator needs