Re: Tuple and changes for m68k with -malign-int

[Richard <richiezid@arcor.de>]

On August 28, 2023 7:00:07 AM UTC, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>On Sun, Aug 27, 2023 at 11:36 AM James Le Cuirot
><chewi@aura-online.co.uk> wrote:
>> On Sun, 2023-08-27 at 10:46 +1000, Finn Thain wrote:
>> > Moreover, why is it that only a few developers have a problem with making
>> > explicit their decisions regarding alignment of shorts? What actual pain
>> > does it cause them to accept a patch to make their struct layouts plain?
>>
>> Some projects do accept patches. Yann Collet was even kind enough to fix this
>> in zstd themselves. On the other hand, we have had to fight to stop Python
>> from dropping m68k support entirely. The real problem is the effort required
>> to produce these patches. I haven't been able to wrap my head around this so
>> far, but I would still like to learn. I could see myself eventually fixing
>> mold, but LLVM feels like a very tall order.
>
>Perhaps we need a new compiler warning: "hole in structure due to
>non-natural alignment, please consider adding explicit padding"?

Sounds reasonable but I am afraid in 99% of cases this would be completely irrelevant and not break anything so the acceptance would be pretty low. 

The problem arises only when people start doing "strange" things with such structs. Can we define strange things in a better way? It appears to me all modern c standards somewhat lack an attribute to mark a struct as being "special use" and thus emit more warnings and avoid some kinds of trickery.

Richard