[fpc-devel] alignment warnings

[Ludo Brands]

> >> Thinking more about the alignment problems on arm and elsewhere, I 
> >> was wondering how hard it would be to implement something 
> like gcc's 
> >> -Wcast-align. Here's a description from the man page:
> >>
> >> Warn whenever a pointer is cast such that the required 
> alignment of 
> >> the target is increased. For example, warn if a "char *" 
> is cast to 
> >> an "int *" on machines where integers can only be accessed 
> at two- or 
> >> four-byte boundaries.
> >
> > The problem with such warnings is that one cannot get easily rid of 
> > them. Maybe a hint would be more suitable.
> 
> Yes, probably, you would want to switch this off most of the 
> time, I guess.  Is this hard to implement?
> 

One of the difficulties is probably pointers to packed records. Depending on
the members of the record the alignment requirement can be 1,2,4 or more
bytes. OS API's contain a lot of these.
Packed records are an aligment "hazard" on their own. They also could use a
warning/hint when members are not on a correctly aligned offset.

Ludo