Hello All,
Richard Guenther wrote:
On Sat, Mar 21, 2009 at 1:17 PM, Basile STARYNKEVITCH
<bas...@starynkevitch.net> wrote:
Hello All,
What is the politically correct way of having an ignored function pointer
inside a GTY-ed struct?
To be more precise, I have
typedef basilys_ptr_t basilysroutfun_t (basilysclosure_ptr_t closp_,
basilys_ptr_t firstargp_,
const char xargdescr_[],
union basilysparam_un *xargtab_,
const char xresdescr_[],
union basilysparam_un *xrestab_);
Of course, the function pointer is obviously GTY ((skip))-ed.
In the MELT branch (file gcc/basilys.h rev144985) I have
// notice that FLEXIBLE_DIM is a macro expanding to empty
#define BASILYS_ROUTDESCR_LEN 96
#define BASILYS_ROUTADDR_LEN (1 + (2*sizeof (basilysroutfun_t *))/ sizeof
(long))
struct basilysroutine_st
GTY (())
{
basilysobject_ptr_t discr;
char routdescr[BASILYS_ROUTDESCR_LEN];
long GTY ((skip)) routaddr[BASILYS_ROUTADDR_LEN];
basilys_ptr_t routdata;
unsigned nbval;
basilys_ptr_t GTY ((length ("%h.nbval"))) tabval[FLEXIBLE_DIM];
};
/* unsafely set inside the basilysroutine_st pointed by Rptr the
routine function pointer to Rout */
#define BASILYS_ROUTINE_SET_ROUTCODE(Rptr,Rout) do { \
(*(basilysroutfun_t**)((struct basilysroutine_st*)(Rptr))->routaddr) \
= (Rout); \
This violates C aliasing rules. As it is a macro I have no idea what Rptr and
Rout point to and thus cannot provide any advice. Please consider
making such *_SET macros inline functions instead (not that this would
fix this particular bug).
I just need to set a function pointer inside a GTY-ed struct. Since
gengtype does not allow these, I tried some trick to circumvent gengtype
limitations.
Any advices on making that cleaner are welcome.
So my point is that I want to put inside the GTY-ed struct
basilysroutine_st an ignored (I mean GTY((skip))-ed) field called
routaddr which is a function pointer
(function of type basilysroutfun_t - which is typedef-ed above).
How can I achieve that, in the cleanest way possible?
Regards.
--
Basile STARYNKEVITCH http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mines, sont seulement les miennes} ***
