Sorry for the late reply (just came back from LPC after Cauldron).
> On Sep 17, 2024, at 05:13, Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Sat, Sep 14, 2024 at 08:58:28PM +0200, Jakub Jelinek wrote:
>> if (has_counted_by_object (e_p->value))
>> expr.value = get_counted_by_ref (e_p->value);
>> else if (in_typeof && TREE_CODE (e_p->value) == COMPONENT_REF)
>> {
>> tree counted_by_type = NULL_TREE;
>> tree arg = (*cexpr_
>> if (build_counted_by_ref (TREE_OPERAND (e_p->value, 0),
>> TREE_OPERAND (e_p->value, 1),
>> &counted_by_type))
>> expr.value
>> = build_zero_cst (build_pointer_type (counted_by_type));
>> else
>> expr.value = null_pointer_node;
>> }
>> else
>> expr.value = null_pointer_node;
>>
>> (plus make build_counted_by_ref non-static and add prototype).
>>
>> Completely untested.
>
> Note, the above I think ought to work with say
> __typeof (__builtin_counted_by_ref (obj->fam))
> or
> __alignof (*__builtin_counted_by_ref (obj->fam))
> but will not work with say
> struct with_fam obj;
> void foo () {
> ...
> __typeof (char [__builtin_counted_by_ref (obj.fam) == &obj.size ? 1 : -1])
> ...
> }
> etc. (and similar for alignof; something like that should go into the
> testsuite).
Sure, will add the above into the testsuite.
thanks.
Qing
> So maybe better
> tree arg = e_p->value;
> tree f;
> if ((in_typeof || in_alignof)
> && TREE_CODE (arg) == COMPONENT_REF
> && (f = TREE_OPERAND (arg, 1))
> && TREE_CODE (f) == FIELD_DECL
> && c_flexible_array_member_type_p (TREE_TYPE (f))
> && lookup_attribute ("counted_by", DECL_ATTRIBUTES (f))
> && DECL_NAME (f))
> arg = build_component_ref (EXPR_LOCATION (arg),
> TREE_OPERAND (arg, 0),
> DECL_NAME (f), UNKNOWN_LOCATION,
> UNKNOWN_LOCATION, true);
> if (has_counted_by_object (arg))
> expr.value = get_counted_by_ref (arg);
> else
> expr.value = null_pointer_node;
>
> Jakub
>
