Re: Thoughts on AdaCore maintaining GCC-incompatible GNAT sources

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 25 Jan 2011 02:29:17 +0100, Randy Brukardt <randy@rrsoftware.com>  
a écrit:
>> What do you mean by "the exact same setup" here ? Can you explain with  
>> an
>> example ?
>
> I meant the same compiler, runtime libraries, tools, etc.
>
>> What would be amazing, would be valid sources not compiling (and most of
>> GNAT is written in Ada). That sound mysterious.
>
> "Ada" is an abstract notion. No compiler implements Ada exactly right,  
> and
> I'm dubious that is even possible. There are literally billions on
> combinations possible, and of course most of those combinations are
> harmless. But there always are some that are not.
> [...]
> Moreover, bugs can extend beyond the source code. The problem I had with  
> the
> Janus/Ada optimizer occurred because the code being optimized was too
> simple! The code was so simple that the optimizer actually was making it
> bigger and that caused the buffer to overflow (since it doesn't know how  
> to
> grow - it's not needed). This isn't the sort of effect that you could  
> notice
> from normal testing -- you actually would have to try to compile packages
> with that sort of code (no test programs were large enough to expose the
> problem).
>
> I'm sure GNAT has somewhat fewer of these issues, as their compiler has  
> more
> users than Janus/Ada does, but that isn't likely to make it free of such
> issues, just a bit less likely to show them.
>
>                           Randy.

So you just increased the quality of your implementation. That's a good.

At least this kind of language or implementation topics are workable and  
stands for goods (this also advocate for the use of more than just a  
single unique compiler), while the troubles which come with different  
build process, environment, available libraries, etc, are less fun (these  
ones are real nightmare).


-- 
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les chiens.

“I am fluent in ASCII” [Warren 2010]