tinycc/lib/va_list.c
grischka 1b57560502 nocode, noreturn
A more automatic approach to code suppression (aka. nocode_wanted)

The simple rules are:
- Clear 'nocode_wanted' at (im/explicit) label IF it was used
- Set 'nocode_wanted' after unconditional jumps

Also in order to test this then I did add the "function might
return no value" warning, and then to make that work again I
did add the __attribute__((noreturn)).

Also moved the look ahead label check into the type parser
to gain a little speed.
2019-06-24 11:40:01 +02:00

67 lines
1.8 KiB
C

/* va_list.c - tinycc support for va_list on X86_64 */
#if defined __x86_64__
/* Avoid include files, they may not be available when cross compiling */
extern void *memset(void *s, int c, __SIZE_TYPE__ n);
extern void abort(void);
/* This should be in sync with our include/stdarg.h */
enum __va_arg_type {
__va_gen_reg, __va_float_reg, __va_stack
};
/* GCC compatible definition of va_list. */
typedef struct {
unsigned int gp_offset;
unsigned int fp_offset;
union {
unsigned int overflow_offset;
char *overflow_arg_area;
};
char *reg_save_area;
} __va_list_struct;
void __va_start(__va_list_struct *ap, void *fp)
{
memset(ap, 0, sizeof(__va_list_struct));
*ap = *(__va_list_struct *)((char *)fp - 16);
ap->overflow_arg_area = (char *)fp + ap->overflow_offset;
ap->reg_save_area = (char *)fp - 176 - 16;
}
void *__va_arg(__va_list_struct *ap,
enum __va_arg_type arg_type,
int size, int align)
{
size = (size + 7) & ~7;
align = (align + 7) & ~7;
switch (arg_type) {
case __va_gen_reg:
if (ap->gp_offset + size <= 48) {
ap->gp_offset += size;
return ap->reg_save_area + ap->gp_offset - size;
}
goto use_overflow_area;
case __va_float_reg:
if (ap->fp_offset < 128 + 48) {
ap->fp_offset += 16;
return ap->reg_save_area + ap->fp_offset - 16;
}
size = 8;
goto use_overflow_area;
case __va_stack:
use_overflow_area:
ap->overflow_arg_area += size;
ap->overflow_arg_area = (char*)((long long)(ap->overflow_arg_area + align - 1) & -align);
return ap->overflow_arg_area - size;
default: /* should never happen */
abort();
return 0;
}
}
#endif