On 2023-12-06 09:21, Jakub Jelinek wrote:
On Wed, Dec 06, 2023 at 02:34:10PM +0100, Martin Uecker wrote:
Further I think
"size less than or equal to the size requested"
is quite ambiguous in the calloc case, isn't the size requested in the
calloc case actually nmemb * size rather than just size?
This is unclear but it can be understood this way.
This was also Joseph's point.
I am happy to submit a patch that changes the code so
that the swapped arguments to calloc do not cause a warning
anymore.
That would be my preference because then the allocation size is
correct and it is purely a style warning.
It doesn't follow how the warning is described:
"Warn about calls to allocation functions decorated with attribute
@code{alloc_size} that specify insufficient size for the target type of
the pointer the result is assigned to"
when the size is certainly sufficient.
But wonder what others think about it.
+1, from a libc perspective, the transposed arguments don't make a
difference, a typical allocator will produce sufficiently sized
allocation for the calloc call.
BTW, shouldn't the warning be for C++ as well? Sure, I know,
people use operator new more often, but still, the <cstdlib>
allocators are used in there as well.
We have the -Wmemset-transposed-args warning, couldn't we
have a similar one for calloc, and perhaps do it solely in
the case where one uses sizeof of the type used in the cast
pointer?
So warn for
(struct S *) calloc (sizeof (struct S), 1)
or
(struct S *) calloc (sizeof (struct S), n)
but not for
(struct S *) calloc (4, 15)
or
(struct S *) calloc (sizeof (struct T), 1)
or similar? Of course check for compatible types of TYPE_MAIN_VARIANTs.
+1, this could be an analyzer warning, since in practice it is just a
code cleanliness issue.
Thanks,
Sid
