Re: [Patch, fortran] PR49213 - [OOP] gfortran rejects structure constructor expression

[Harald Anlauf <anlauf@gmx.de>]

Hi Paul,

this is much better now.

I have only a minor comment left: in the calculation of the
size of a character string you are using an intermediate
gfc_array_index_type, whereas I have learned to use
gfc_charlen_type_node now, which seems like the natural
type here.

OK for trunk, and thanks for your patience!

Harald


On 6/27/23 12:30, Paul Richard Thomas via Gcc-patches wrote:
> Hi Harald,
> 
> Let's try again :-)
> 
> OK for trunk?
> 
> Regards
> 
> Paul
> 
> Fortran: Enable class expressions in structure constructors [PR49213]
> 
> 2023-06-27  Paul Thomas  <pault@gcc.gnu.org>
> 
> gcc/fortran
> PR fortran/49213
> * expr.cc (gfc_is_ptr_fcn): Remove reference to class_pointer.
> * resolve.cc (resolve_assoc_var): Call gfc_is_ptr_fcn to allow
> associate names with pointer function targets to be used in
> variable definition context.
> * trans-decl.cc (get_symbol_decl): Remove extraneous line.
> * trans-expr.cc (alloc_scalar_allocatable_subcomponent): Obtain
> size of intrinsic and character expressions.
> (gfc_trans_subcomponent_assign): Expand assignment to class
> components to include intrinsic and character expressions.
> 
> gcc/testsuite/
> PR fortran/49213
> * gfortran.dg/pr49213.f90 : New test
> 
> On Sat, 24 Jun 2023 at 20:50, Harald Anlauf <anlauf@gmx.de> wrote:
>>
>> Hi Paul!
>>
>> On 6/24/23 15:18, Paul Richard Thomas via Gcc-patches wrote:
>>> I have included the adjustment to 'gfc_is_ptr_fcn' and eliminating the
>>> extra blank line, introduced by my last patch. I played safe and went
>>> exclusively for class functions with attr.class_pointer set on the
>>> grounds that these have had all the accoutrements checked and built
>>> (ie. class_ok). I am still not sure if this is necessary or not.
>>
>> maybe it is my fault, but I find the version in the patch confusing:
>>
>> @@ -816,7 +816,7 @@ bool
>>    gfc_is_ptr_fcn (gfc_expr *e)
>>    {
>>      return e != NULL && e->expr_type == EXPR_FUNCTION
>> -             && (gfc_expr_attr (e).pointer
>> +             && ((e->ts.type != BT_CLASS && gfc_expr_attr (e).pointer)
>>                     || (e->ts.type == BT_CLASS
>>                         && CLASS_DATA (e)->attr.class_pointer));
>>    }
>>
>> The caller 'gfc_is_ptr_fcn' has e->expr_type == EXPR_FUNCTION, so
>> gfc_expr_attr (e) boils down to:
>>
>>         if (e->value.function.esym && e->value.function.esym->result)
>>          {
>>            gfc_symbol *sym = e->value.function.esym->result;
>>            attr = sym->attr;
>>            if (sym->ts.type == BT_CLASS && sym->attr.class_ok)
>>              {
>>                attr.dimension = CLASS_DATA (sym)->attr.dimension;
>>                attr.pointer = CLASS_DATA (sym)->attr.class_pointer;
>>                attr.allocatable = CLASS_DATA (sym)->attr.allocatable;
>>              }
>>          }
>> ...
>>         else if (e->symtree)
>>          attr = gfc_variable_attr (e, NULL);
>>
>> So I thought this should already do what you want if you do
>>
>> gfc_is_ptr_fcn (gfc_expr *e)
>> {
>>     return e != NULL && e->expr_type == EXPR_FUNCTION && gfc_expr_attr
>> (e).pointer;
>> }
>>
>> or what am I missing?  The additional checks in gfc_expr_attr are
>> there to avoid ICEs in case CLASS_DATA (sym) has issues, and we all
>> know Gerhard who showed that he is an expert in exploiting this.
>>
>> To sum up, I'd prefer to use the safer form if it works.  If it
>> doesn't, I would expect a latent issue.
>>
>> The rest of the code looked good to me, but I was suspicious about
>> the handling of CHARACTER.
>>
>> Nasty as I am, I modified the testcase to use character(kind=4)
>> instead of kind=1 (see attached).  This either fails here (stop 10),
>> or if I activate the marked line
>>
>> !    cont = tContainer('hello!')       ! ### ICE! ###
>>
>> I get an ICE.
>>
>> Can you have another look?
>>
>> Thanks,
>> Harald
>>
>>>
>>
>>> OK for trunk?
>>>
>>> Paul
>>>
>>> Fortran: Enable class expressions in structure constructors [PR49213]
>>>
>>> 2023-06-24  Paul Thomas  <pault@gcc.gnu.org>
>>>
>>> gcc/fortran
>>> PR fortran/49213
>>> * expr.cc (gfc_is_ptr_fcn): Guard pointer attribute to exclude
>>> class expressions.
>>> * resolve.cc (resolve_assoc_var): Call gfc_is_ptr_fcn to allow
>>> associate names with pointer function targets to be used in
>>> variable definition context.
>>> * trans-decl.cc (get_symbol_decl): Remove extraneous line.
>>> * trans-expr.cc (alloc_scalar_allocatable_subcomponent): Obtain
>>> size of intrinsic and character expressions.
>>> (gfc_trans_subcomponent_assign): Expand assignment to class
>>> components to include intrinsic and character expressions.
>>>
>>> gcc/testsuite/
>>> PR fortran/49213
>>> * gfortran.dg/pr49213.f90 : New test
> 
> 
>