Hi,
Thanks for the response. I see this behavior with both 'leaf' and 'non-leaf' functions. For example, the following call tree will fail:
void testFunc2()
{
printf("Hello\n");
}
void testFunc()
{
char buf[10]; /* this is aligned at a 1-byte boundary */
...
testFunc2(); /* this should make it non-leaf right? */
}
int main(int argc, char* argv[])
{
testFunc();
}
Moving the declaration of 'buf' up to main() also results in the 1-byte alignment, even with the calls to testFunc(). Am I mistaken in my interpretation of 'leaf' functions?
-Amruth
-------------- Original message from "John (Eljay) Love-Jensen" <eljay@xxxxxxxxx>: --------------
> Hi Amruth,
>
> Is someFunction() a leaf function (i.e., it does not call any other non-inlined
> function)?
>
> As I understand the ABI specification, if it is a leaf function, the ABI
> regarding alignment is not relevant.
>
> If it isn't a leaf function, that sounds like a compiler bug.
>
> >1. Has anyone else experienced the same behavior? I'd like to rule out
> configuration issues.
>
> No, I use GCC 3.2 on SPARC. (Not my choice. My druthers would be to use the
> head of the current release.)
>
> But I also do not write code that relies on alignment assumptions. If I have
> alignment constraints, I'd use a union or GCC's alignment qualifier extension so
> the constraint is explicit in the code and not assumed.
>
> >2. Assuming this is not a configuration issue, does anyone have information as
> to why such a change was made?
>
> I assume that the change was made because the SPARC ABI does not impose stack
> alignment on leaf functions (if the situation is a leaf function).
>
> I may be mistaken.
>
> >3. Does anyone know of any compiler options that would produce the same results
> globally?
>
> No, sorry. There could be one, but I'm not familiar with it.
>
> But I do recommend using current release GCC 4.2.1 or at least the patched up
> GCC 4.1.2 instead of GCC 4.1.0.
>
> HTH,
> --Eljay
