Re: wishlist: support for shorter pointers

[Martin Uecker <muecker@gwdg.de>]

Am Mittwoch, dem 05.07.2023 um 11:11 +0200 schrieb David Brown:
> On 05/07/2023 10:05, Rafał Pietrak via Gcc wrote:

...
> 
> In my personal opinion (which you are all free to disregard), named 
> address spaces were an interesting idea that failed.  I was
> enthusiastic 
> about a number of the extensions in TR 18307 "C Extensions to support
> embedded processors" when the paper was first published.  As I
> learned 
> more, however, I saw it was a dead-end.  The features are too 
> under-specified to be useful or portable, gave very little of use to 
> embedded programmers, and fit badly with C.  It was an attempt to 
> standardise and generalise some of the mess of different extensions
> that 
> proprietary toolchain developers had for a variety of 8-bit CISC 
> microcontrollers that could not use standard C very effectively.  But
> it 
> was all too little, too late - and AFAIK none of these proprietary 
> toolchains support it.  GCC supports some of the features to some
> extent 
> - a few named address spaces on a few devices, for "gnuc" only (not 
> standard C, and not C++), and has some fixed point support for some 
> targets (with inefficient generated code - it appears to be little
> more 
> than an initial "proof of concept" implementation).
> 
> I do not think named address spaces have a future - in GCC or
> anywhere 
> else.  The only real use of them at the moment is for the AVR for 
> accessing data in flash, and even then it is of limited success since
> it 
> does not work in C++.

Can you explain a little bit why you think it is a dead-end?  It
seems an elegant solution to a range of problems to me.

I have no idea how much the GCC features are actually used,
but other compilers for  embedded systems such as SDCC also 
support named address spaces.  


Martin