Re: wishlist: support for shorter pointers

[Martin Uecker <muecker@gwdg.de>]

Am Mittwoch, dem 05.07.2023 um 10:05 +0200 schrieb Rafał Pietrak:
> Hi,
> 
> W dniu 5.07.2023 o 09:29, Martin Uecker pisze:
> > Am Mittwoch, dem 05.07.2023 um 07:26 +0200 schrieb Rafał Pietrak:
> [-------]
> > > And if it's so ... there is no mention of how does it show up for
> > > "simple user" of the GCC (instead of the use of that "machinery"
> > > by
> > > creators of particular GCC port). In other words: how the sources
> > > should
> > > look like for the compiler to do "the thing"?
> > > 
> > 
> > Not sure I understand the question.  You would add a name space
> > to an object as a qualifier and then the object would be allocated
> > in a special (small) region of memory.  Pointers known to point
> > into that special region of memory (which is encoded into the
> > type) would then be smaller.  At least, this is my understanding
> > of how it could work.
> 
> Apparently you do understand my question.
> 
> Then again ... apparently you are guessing the answer. Incidentally, 
> that would be my guess, too. And while such "syntax" is not really 
> desirable (since such attribution at every declaration of every
> "short 
> pointer" variable would significantly obfuscate the sources and a
> thing 
> like "#pragma" at the top of a file would do a better job), better 
> something then nothing. 

If you want to mix pointers I think it would make the code clearer
if the name space is explicit.  But yes, you would need to add
those annotations.

But maybe one could also consider a pragma that sets a default 
name space mode for some region of code in the source.   

> Then again, should you happen to fall onto an 
> actual documentation of syntax to use this feature with, I'd
> appreciate 
> you sharing it :)

Sorry, I thought I shared this before:

https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html

The draft specification mentioned there can be found herE:

https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1275.pdf



Martin