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 <pa...@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
! { dg-do run }
!
! Contributed by Neil Carlson <neil.n.carl...@gmail.com>
!
program main
! character(2) :: c
character(2,kind=4) :: c
type :: S
integer :: n
end type
type(S) :: Sobj
type, extends(S) :: S2
integer :: m
end type
type(S2) :: S2obj
type :: T
class(S), allocatable :: x
end type
type(T) :: Tobj
Sobj = S(1)
Tobj = T(Sobj)
S2obj = S2(1,2)
Tobj = T(S2obj) ! Failed here
select type (x => Tobj%x)
type is (S2)
if ((x%n .ne. 1) .or. (x%m .ne. 2)) stop 1
class default
stop 2
end select
c = 4_" "
call pass_it (T(Sobj))
if (c .ne. 4_"S ") stop 3
call pass_it (T(S2obj)) ! and here
if (c .ne. 4_"S2") stop 4
call bar
contains
subroutine pass_it (foo)
type(T), intent(in) :: foo
select type (x => foo%x)
type is (S)
c = 4_"S "
if (x%n .ne. 1) stop 5
type is (S2)
c = 4_"S2"
if ((x%n .ne. 1) .or. (x%m .ne. 2)) stop 6
class default
stop 7
end select
end subroutine
subroutine bar
! Test from comment #29 of the PR - due to Janus Weil
type tContainer
class(*), allocatable :: x
end type
integer, parameter :: i = 0
character(7,kind=4) :: chr = 4_"goodbye"
type(tContainer) :: cont
cont%x = i ! linker error: undefined reference to `__copy_INTEGER_4_.3804'
cont = tContainer(i+42) ! Failed here
select type (z => cont%x)
type is (integer)
if (z .ne. 42) stop 8
class default
stop 9
end select
! cont = tContainer('hello!') ! ### ICE! ###
cont = tContainer(4_'hello!')
select type (z => cont%x)
type is (character(*,kind=4))
if (z .ne. 4_'hello!') stop 10
class default
stop 11
end select
cont = tContainer(chr)
select type (z => cont%x)
type is (character(*,kind=4))
if (z .ne. 4_'goodbye') stop 12
class default
stop 13
end select
end subroutine bar
end program
