🚀 go-pugleaf

As I don't save all the bug reports going by, I don't know if this has already
been reported.

Anyway, here is a bug report and a fix.

Both gcc and g++ use the same architecture-dependend include file for
<stdarg.h>. In my case, va-sparc.h. This file contains the SPARC
definition of va_arg(pvar,TYPE).

The definition gives wrong results if sizeof (TYPE) < sizeof (int);
The part that does the argument fetch dereferences the starting
address of the argument with a *(TYPE*). This is correct for large
arguments (>= sizeof (int)). For a small argument, it works correctly
only on a little endian architecture. SPARC isn't.

I have fixed this by testing for small argument types and dereferencing
the pointer as an int *, *then* casting to TYPE. This should work on
all architectures, big or little endian, but I'm currently only interested
in SPARC.

Attached is a context diff with the entire macro.


*** va-sparc.h.orig	Sun Jun 21 11:41:38 1992
--- va-sparc.h	Thu Aug  6 14:05:49 1992
***************
*** 51,64 ****
--- 51,66 ----
  #define va_arg(pvar,TYPE)					\
  __extension__							\
  ({ 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),			\
+        (sizeof (TYPE) < sizeof (int)) ?                         \
+        (TYPE) *((int *) ((pvar) - __va_rounded_size (TYPE))) :  \
         *((TYPE *) ((pvar) - __va_rounded_size (TYPE)))));})

| ...!unido!ukw!lupe  (German EUNet, "bang")     |  Disclaimer:            |
| lupe@ukw.UUCP       (German EUNet, domain)     |  As I am self-employed, |
| suninfo!alanya!lupe (Sun Germany)              |  this *is* the opinion  |
| Res non sunt complicanda praeter necessitatem. |  of my employer.        |