Re: [PATCH] Introduce abi_word_mode

[Richard Sandiford <richard at codesourcery dot com>]

This probably isn't going to advance the discussion much, but...

Andreas Krebbel <Andreas.Krebbel@de.ibm.com> writes:
>> I agree with Geoff that this is an attribute we could do without, though 
>> I don't know how practical it is to remove it.  Whatever you can do with 
>> "word" mode, you can also do with "int" on 90% of all platforms, and 
>> with a teeny bit of autoconf on the remainder.
>
> Is there really a chance to remove it?!  Since it is documented in the gcc 
> manual we have to consider that everybody makes use of it - right?!.  Even 
> if it is not widely used and its uses are arguable I would think we are stuck
> with it.

...IMO, this point argues against the change you're trying to make.
You're effectively trying to _redefine_ what the attribute means,
and one of the drawbacks of that is precisely that it may hurt people
who are already using it.  gcc is doing what the documentation says
(mainly thanks to woolly documentation) and the people that make
use of it may expect it to do what it does now: provide the size
of a general purpose register.  It's really a case of which target
audience you choose to side with.

(Even if you're using a 32-bit compatibilty calling convention,
the 64-bitness of the code that the system has to run is still
technically part of the ABI.  I think from that point of view
that the current definition of mode(word) is still an ABI property.)

The status quo has the advantage of being what previous compilers do,
and of being easier to understand.  The EH symbols aren't mangled,
so if they are a concern, it seems better to just change the types
(unless it's OK to continue compiling them in 32-bit mode).

Richard