Re: [Tinycc-devel] x86_64: second struct va_arg fails

[grischka]

shinichiro hamaji wrote:
> This is one of my TODO. I think the easiest way would be adding a
> builtin function like __builtin_aggregate_types_p and using it in
> stdarg.h. I hesitated to do this because any other compilers don't
> have such extensions. A better way would be defining __builtin_va_arg
> just like GCC. I guess I will have some spare time this year end. I'll
> try working on this if no one don't fix.

Maybe you can use a support function in combination with a builtin.
This would keep the generated code reasonably small and most of the
logic could be in convenient C.  Such as:

in stdarg.h:
  #define va_arg(ap,type) *(type)*__va_arg(ap, __builtin_va_type(type))
and in libtcc1.c:
  enum va_type { va_reg, va_double, va_aggregate, ... };
  void *__va_arg(va_list ap, int va_type)
  {
    switch(va_type) [
    ...

Btw, I was wondering whether alignment '4' for structures is correct.
Basically registers and mmx would possibly go on top of some structure
in the overflow_area when the register space is used up.  There could
also be doubles in a structure.  Just wondering.

--- grischka