🚀 go-pugleaf

The following short program generates four warnings of the form
"warning: cast increases required alignment of target type" when
compiled with sparc gcc 2.2.2 -Wcast-align:

	#include <stdarg.h>

	void
	foo(char *arg1, ...)
	{
		va_list ap;
		char *p;
		va_start(ap, arg1);
		p = va_arg(ap, char *);		/* warnings flagged here */
	}

The errors come from the definition of va_arg in <va-sparc.h>.  Since the
usage here is correct, the errors should be suppressed, which can be done
by casting the offending pointers to (void *).  Simply making pvar be a
"void *" fails since we need the increment-by-one property of "char *"
in va_arg().  The generated code is the same (not surprisingly).

*** 1.1	1992/10/07 02:53:12
--- va-sparc.h	1992/10/07 02:53:43
***************
*** 53,64 ****
  ({ TYPE __va_temp;						\
     ((__builtin_classify_type (__va_temp) >= 12)			\
      ? ((pvar) += __va_rounded_size (TYPE *),			\
!        **(TYPE **) ((pvar) - __va_rounded_size (TYPE *)))	\
      : __va_rounded_size (TYPE) == 8				\
      ? ({ union {TYPE d; int i[2];} u;				\
! 	 u.i[0] = ((int *) (pvar))[0];				\
! 	 u.i[1] = ((int *) (pvar))[1];				\
  	 (pvar) += 8;						\
  	 u.d; })						\
      : ((pvar) += __va_rounded_size (TYPE),			\
!        *((TYPE *) ((pvar) - __va_rounded_size (TYPE)))));})
--- 53,64 ----
  ({ TYPE __va_temp;						\
     ((__builtin_classify_type (__va_temp) >= 12)			\
      ? ((pvar) += __va_rounded_size (TYPE *),			\
!        **(TYPE **) (void *) ((pvar) - __va_rounded_size (TYPE *)))	\
      : __va_rounded_size (TYPE) == 8				\
      ? ({ union {TYPE d; int i[2];} u;				\
! 	 u.i[0] = ((int *) (void *) (pvar))[0];			\
! 	 u.i[1] = ((int *) (void *) (pvar))[1];			\
  	 (pvar) += 8;						\
  	 u.d; })						\
      : ((pvar) += __va_rounded_size (TYPE),			\
!        *((TYPE *) (void *) ((pvar) - __va_rounded_size (TYPE)))));})

--
			Chris Metcalf, MIT Laboratory for Computer Science
			metcalf@cag.lcs.mit.edu   //   +1 (617) 253-7766