[Bug fortran/60357] New: structure constructor with unspecified values for allocatable components

[Bug fortran/60357] New: structure constructor with unspecified values for allocatable components

[antony at cosmologist dot info]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

            Bug ID: 60357
           Summary: structure constructor with unspecified values for
                    allocatable components
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: antony at cosmologist dot info

This valid F2008 code is rejected:


    module testmod
    Type A
        integer :: X = 1
        integer, allocatable :: y 
    end type A
    end module

    program testerprog
    use testmod
    Type(A) :: Me = A(X=1)

    end program


Compiler error is:

Type(A) :: Me = A(X=1)
               1
Error: No initializer for component 'y' given in the structure constructor at
(1)!

However initialization statements are not required for allocatable components.

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #2 from janus at gcc dot gnu.org ---
Draft patch:

Index: gcc/fortran/array.c
===================================================================
--- gcc/fortran/array.c    (revision 208207)
+++ gcc/fortran/array.c    (working copy)
@@ -1307,6 +1307,9 @@ check_constructor (gfc_constructor_base ctor, bool
   for (c = gfc_constructor_first (ctor); c; c = gfc_constructor_next (c))
     {
       e = c->expr;
+      
+      if (!e)
+    continue;

       if (e->expr_type != EXPR_ARRAY)
     {
Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c    (revision 208207)
+++ gcc/fortran/expr.c    (working copy)
@@ -2200,7 +2200,7 @@ check_alloc_comp_init (gfc_expr *e)
        ctor = gfc_constructor_first (e->value.constructor);
        comp; comp = comp->next, ctor = gfc_constructor_next (ctor))
     {
-      if (comp->attr.allocatable
+      if (comp->attr.allocatable && ctor->expr
           && ctor->expr->expr_type != EXPR_NULL)
         {
       gfc_error("Invalid initialization expression for ALLOCATABLE "
Index: gcc/fortran/primary.c
===================================================================
--- gcc/fortran/primary.c    (revision 208207)
+++ gcc/fortran/primary.c    (working copy)
@@ -2365,6 +2365,13 @@ build_actual_constructor (gfc_structure_ctor_compo
         return false;
           value = gfc_copy_expr (comp->initializer);
         }
+      else if (comp->attr.allocatable)
+        {
+          if (!gfc_notify_std (GFC_STD_F2008, "No initializer for "
+          "allocatable component '%s' given in the structure "
+          "constructor at %C", comp->name))
+        return false;
+        }
       else
         {
           gfc_error ("No initializer for component '%s' given in the"

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |janus at gcc dot gnu.org

--- Comment #3 from janus at gcc dot gnu.org ---
(In reply to janus from comment #2)
> Draft patch:

... regtests cleanly!

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #4 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Note that while

    program testerprog
    use testmod
    Type(A) :: Me
    Me%y=2
    print *, Me%x, Me%y

    end program

gives at run time

           1           2

    program testerprog
    use testmod
    Type(A) :: Me
    allocate(Me%y)
    Me = A(X=1, y=2)
    print *, Me%y

    end program

gives

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
The patch in comment 2 needs to be update to

--- ../_clean/gcc/fortran/primary.c    2014-12-16 22:27:14.000000000 +0100
+++ gcc/fortran/primary.c    2014-12-21 14:50:53.000000000 +0100
@@ -2367,6 +2367,13 @@ build_actual_constructor (gfc_structure_
         return false;
           value = gfc_copy_expr (comp->initializer);
         }
+      else if (comp->attr.allocatable)
+        {
+          if (!gfc_notify_std (GFC_STD_F2008, "No initializer for "
+          "allocatable component '%s' given in the structure "
+          "constructor at %C", comp->name))
+        return false;
+        }
       else if (!comp->attr.deferred_parameter)
         {
           gfc_error ("No initializer for component %qs given in the"

Note that while

    program testerprog
    use testmod
    Type(A) :: Me
    allocate(Me%y)
    Me = A(X=1, y=2)
    print *, Me%y

    end program

gives

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

    program testerprog
    use testmod
    Type(A) :: Me
    Me = A(X=1, y=2)
    print *, Me%x, Me%y

    end program

gives

           1           2

i.e., 'allocate(Me%y)' conflicts with Me = A(X=1, y=2). May be this expected.

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #6 from janus at gcc dot gnu.org ---
(In reply to Dominique d'Humieres from comment #4)
>     program testerprog
>     use testmod
>     Type(A) :: Me
>     allocate(Me%y)
>     Me = A(X=1, y=2)
>     print *, Me%y
> 
>     end program
> 
> gives
> 
> Program received signal SIGSEGV: Segmentation fault - invalid memory
> reference.

Confirmed. However, this segfault is not related to the original bug (nor to
the patch I posted). It's a separate issue.

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #7 from janus at gcc dot gnu.org ---
Author: janus
Date: Mon Dec 29 10:45:21 2014
New Revision: 219098

URL: https://gcc.gnu.org/viewcvs?rev=219098&root=gcc&view=rev
Log:
2014-12-29  Janus Weil  <janus@gcc.gnu.org>

    PR fortran/60357
    * array.c (check_constructor): Ignore empty expressions.
    * expr.c (check_alloc_comp_init): Check if constructor expression
    exists.
    * primary.c (build_actual_constructor): Warn for absent alloc-comp
    initializers in pre-2008 standards.

2014-12-29  Janus Weil  <janus@gcc.gnu.org>

    PR fortran/60357
    * gfortran.dg/alloc_comp_constructor_7.f90: New.

Added:
    trunk/gcc/testsuite/gfortran.dg/alloc_comp_constructor_7.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/array.c
    trunk/gcc/fortran/expr.c
    trunk/gcc/fortran/primary.c
    trunk/gcc/testsuite/ChangeLog

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #8 from janus at gcc dot gnu.org ---
The original problem in comment 0 is fixed with r219098. Thanks to Anthony for
reporting this!

TODO: The segfault reported by Dominique in comment 4 and 5.

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[vehre at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

Andre Vehreschild <vehre at gmx dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vehre at gmx dot de

--- Comment #9 from Andre Vehreschild <vehre at gmx dot de> ---
Hi Janus,

be careful with the code in comment #4 and #5. When I remember correctly then
it was me who added the allocate trying to understand how Fortran worked there.
Meaning: That must not be valid Fortran. In fact, does my current work on this
pr and on #61275 report that Me%y is already allocated and must not be
reallocated again. 

That is, I may already have a patch that touches the issue. I just need to
figure, if allocating the component explicitly is valid in Fortran. Do you know
something about that? I am still reading the Fortran standards, but haven't
found the location that answers my question.

Andre

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #10 from janus at gcc dot gnu.org ---
(In reply to Andre Vehreschild from comment #9)
> I just need to
> figure, if allocating the component explicitly is valid in Fortran.

For sure. I think both the examples in comment 4 and 5 are actually valid
Fortran code.

In order to make sure we're talking about the same thing, let's have a look at
the following code:

Type A
  integer :: X = 1
  integer, allocatable :: y
end type
Type(A) :: Me
allocate(Me%y)
print *,"A"
Me = A(X=1, y=2)
print *,"B"
print *, Me%y
end

This is a variant of the example above that produced the segfault. I inserted
some print statements in order to debug it. It prints at runtime:

 A
 B

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.


This shows clearly that the segfault occurs when we try to access Me%y in the
last print statement, meaning that it is probably unallocated although it
clearly should be.

-fdump-tree-original shows that the problem is in the translation of the
structure constructor assignment, which apparently leaves the y-component
unallocated.

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[vehre at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #11 from Andre Vehreschild <vehre at gmx dot de> ---
Hi Janus,

before you invest too much time into that: My current patch level produces
intermediate code as attached (for a slightly different program, also
attached).
I was solving the (re-)alloc on assign issue like in PR61275. I now run into
the
runtime error: 

At line 15 of file test_pr60357.f08: Attempting to allocate
already allocated variable 'de'.

Obviously I have over fullfilled the needed allocs:

(1) a.5.y is allocated
(2) a.4.y is allocated
(3) a.0.y is allocated
(4) de.y is allocated
(5) a.2.y is allocated

I am wondering which allocs should really be done, and which one are accidently
added. I doubt that (1) and (2) should be there. (3) and (5) are ok imho. Now
my client (the reporter of the bug, Antony) tells me, that (4) is valid Fortran
("valid" by ifort), but the allocate(De%y) is useless there, as it is freed
before the constructor assign with implicit alloc is done. With my current
patch level, your program would be running fine, because I would auto alloc y
on the assignment.

To summarize my questions: 

Which allocs should be done? 

Given the too allocs in (1) and (2) are removed, would the intermediate code be
correct for the fortran?

Can you help me on this.

Regards,
    Andre


On Mon, 29 Dec 2014 16:42:01 +0000
"janus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357
> 
> --- Comment #10 from janus at gcc dot gnu.org ---
> (In reply to Andre Vehreschild from comment #9)
> > I just need to
> > figure, if allocating the component explicitly is valid in Fortran.
> 
> For sure. I think both the examples in comment 4 and 5 are actually valid
> Fortran code.
> 
> In order to make sure we're talking about the same thing, let's have a look at
> the following code:
> 
> Type A
>   integer :: X = 1
>   integer, allocatable :: y
> end type
> Type(A) :: Me
> allocate(Me%y)
> print *,"A"
> Me = A(X=1, y=2)
> print *,"B"
> print *, Me%y
> end
> 
> This is a variant of the example above that produced the segfault. I inserted
> some print statements in order to debug it. It prints at runtime:
> 
>  A
>  B
> 
> Program received signal SIGSEGV: Segmentation fault - invalid memory
> reference.
> 
> 
> This shows clearly that the segfault occurs when we try to access Me%y in the
> last print statement, meaning that it is probably unallocated although it
> clearly should be.
> 
> -fdump-tree-original shows that the problem is in the translation of the
> structure constructor assignment, which apparently leaves the y-component
> unallocated.
>

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[vehre at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #12 from Andre Vehreschild <vehre at gmx dot de> ---
Created attachment 34353
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34353&action=edit
test_pr60357.f08

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[pault at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

--- Comment #13 from Paul Thomas <pault at gcc dot gnu.org> ---
Author: pault
Date: Sat Jan 17 18:08:38 2015
New Revision: 219801

URL: https://gcc.gnu.org/viewcvs?rev=219801&root=gcc&view=rev
Log:
2015-01-17  Andre Vehreschild  <vehre@gmx.de>

    PR fortran/60357
    * primary.c (build_actual_constructor): Prevent warning.
    * trans-expr.c (alloc_scalar_allocatable_for_subcomponent_
    assignment): New function encapsulates treatment of allocatable
    components.
    (gfc_trans_subcomponent_assign): Needed to distinguish between
    regular assignment and initilization.
    (gfc_trans_structure_assign): Same.
    (gfc_conv_structure): Same.

    PR fortran/61275
    * gfortran.h: deferred_parameter is not needed, because
    it artificial does the trick completely.
    * primary.c (build_actual_constructor): Same.
    (gfc_convert_to_structure_constructor): Same.
    * resolve.c (resolve_fl_derived0): Same.
    * trans-expr.c (gfc_conv_component_ref): Prevent treating
    allocatable deferred length char arrays here.
    (gfc_trans_subcomponent_assign): Same as above.
    * trans-types.c (gfc_sym_type): This is done in
    gfc_get_derived_type already.

2015-01-17  Andre Vehreschild  <vehre@gmx.de>

    PR fortran/60357
    * gfortran.dg/alloc_comp_assign_13.f08: New test.

    PR fortran/61275
    * gfortran.dg/alloc_comp_assign_14.f08: New test.

    PR fortran/55932
    * gfortran.dg/alloc_comp_initializer_4.f03: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/alloc_comp_assign_13.f08
    trunk/gcc/testsuite/gfortran.dg/alloc_comp_assign_14.f08
    trunk/gcc/testsuite/gfortran.dg/alloc_comp_initializer_4.f03
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/gfortran.h
    trunk/gcc/fortran/primary.c
    trunk/gcc/fortran/resolve.c
    trunk/gcc/fortran/trans-expr.c
    trunk/gcc/fortran/trans-types.c
    trunk/gcc/testsuite/ChangeLog

[Bug fortran/60357] [F08] structure constructor with unspecified values for allocatable components

[vehre at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60357

vehre at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
                 CC|                            |vehre at gcc dot gnu.org
         Resolution|---                         |FIXED

--- Comment #14 from vehre at gcc dot gnu.org ---
IMHO does the supplied patch fix all issues discussed in this pr. I therefore
close it. 

Feel free to reopen and assign it to me, when you find some issue not
addressed.