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Add support for struct > 4B returned via registers

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On ARM with hardfloat calling convention, structure containing 4 fields
or less of the same float type are returned via float registers. This
means that a structure can be returned in up to 4 double registers in a
structure is composed of 4 doubles. This commit adds support for return
of structures in several registers.
This commit is contained in:
Thomas Preud'homme
2013-11-22 09:27:15 +08:00
parent d9d60a1ebd
commit dcec8673f2
5 changed files with 77 additions and 49 deletions
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48
arm-gen.c
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@ -746,24 +746,6 @@ static void gcall_or_jmp(int is_jmp)
}
}
/* Return 1 if this function returns via an sret pointer, 0 otherwise */
ST_FUNC int gfunc_sret(CType *vt, CType *ret, int *ret_align) {
#ifdef TCC_ARM_EABI
int size, align;
size = type_size(vt, &align);
if (size > 4) {
return 1;
} else {
*ret_align = 4;
ret->ref = NULL;
ret->t = VT_INT;
return 0;
}
#else
return 1;
#endif
}
#ifdef TCC_ARM_HARDFLOAT
/* Return whether a structure is an homogeneous float aggregate or not.
The answer is true if all the elements of the structure are of the same
@ -831,6 +813,33 @@ int assign_vfpreg(struct avail_regs *avregs, int align, int size)
}
#endif
/* Return the number of registers needed to return the struct, or 0 if
returning via struct pointer. */
ST_FUNC int gfunc_sret(CType *vt, CType *ret, int *ret_align) {
#ifdef TCC_ARM_EABI
int size, align;
size = type_size(vt, &align);
#ifdef TCC_ARM_HARDFLOAT
if (is_float(vt->t) || is_hgen_float_aggr(vt)) {
*ret_align = 8;
ret->ref = NULL;
ret->t = VT_DOUBLE;
return (size + 7) >> 3;
} else
#endif
if (size > 4) {
return 0;
} else {
*ret_align = 4;
ret->ref = NULL;
ret->t = VT_INT;
return 1;
}
#else
return 0;
#endif
}
/* Parameters are classified according to how they are copied to their final
destination for the function call. Because the copying is performed class
after class according to the order in the union below, it is important that
@ -1198,6 +1207,9 @@ void gfunc_prolog(CType *func_type)
n = nf = 0;
variadic = (func_type->ref->c == FUNC_ELLIPSIS);
if((func_vt.t & VT_BTYPE) == VT_STRUCT
#ifdef TCC_ARM_HARDFLOAT
&& (variadic || !is_hgen_float_aggr(&func_vt))
#endif
&& type_size(&func_vt,&align) > 4)
{
n++;