[PATCH 1/7] score: Add RTEMS_DECONST|DEVOLATILE|DEQUALIFY()

[Sebastian Huber]

Hello Pavel,

On 07/09/14 22:34, Pavel Pisa wrote:
> Hello Sebastian and Joel,
>
> On Friday 05 of September 2014 16:04:40 Sebastian Huber wrote:
>> On 05/09/14 15:53, Joel Sherrill wrote:
>>> Why add these?
>>
>> To be independent of Newlib.  We can also use the one in Newlib
>> <sys/cdefs.h>, but we should use a common macro for this stuff, since this
>> documents the intention and you can grep for it.
>
> If there are not some other variants/tricks for these macros
> which would be used for GCC/featured compilers, I do not feel
> good about them.
>
> They suppress relatively harmless warning which can be filterred
> out by GCC options or pragmas for price of hiding serious problems
> when pointer to incorrect type is used.

I think we should eventually use -Werror, so it is important to get rid of 
warnings.  I am in favour of macros, since this makes it easier to deal with 
compiler dependencies.

>
> I fought with these in my projects some years ago and I have
> been motivated by actual need of RTEMS to look at my solution again
> and I think that I have found solution which should help to catch
> most of mistakes and suppress warning about intentional qualifiers
> removal. If the solution is not too obscure for your taste, I suggest
> to adapt it for RTEMS. My latest changes allow to use qualifiers
> removal macro even for global variables initializers even that
> there is not produced nice diagnostic message "UL_CAST_UNQX types
> differ not only by volatile and const" but "critic initializer is
> not constant". Each of macros, UL_CAST_UNQ1, UL_CAST_UNQ2,
> or UL_CAST_UNQ3 expects pointer of reference level 1/2/3
> and removes const/volatile to given depth. I have been
> inspired during my attempts by libHX from Jan Engelhardt
> but my solution works even for global initializers
> and I think that it is even simpler in the end.

I think it would be very good to make the macros in basedefs.h more bullet 
proof, but I don't have a spare time budget for this at the moment.


-- 
Sebastian Huber, embedded brains GmbH

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