[Bug fortran/35983] New: C_LOC in derived type constructor gives weird result

[Bug fortran/35983] New: C_LOC in derived type constructor gives weird result

[fxcoudert at gcc dot gnu dot org]

$ cat a.f90 
program main
   use ISO_C_BINDING
   implicit none
   type, bind(C) :: descr
      type(C_PTR) :: address
   end type descr
   type(descr) :: DD
   double precision, target :: buf(1)

   buf = (/ 0 /)
   DD = descr(c_loc(buf))
   print *, transfer(DD%address, 0_c_intptr_t), &
     transfer(c_loc (buf), 0_c_intptr_t)
end program main

$ gfortran a.f90 && ./a.out
           0 -1073744200


-- 
           Summary: C_LOC in derived type constructor gives weird result
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: fxcoudert at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983

[Bug fortran/35983] C_LOC in derived type constructor gives weird result

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2008-04-20 11:40 -------
Confirm. While for
   type(c_ptr) :: cptr
   cptr = c_loc(buf)

the dump is:
      void * D.910;
      D.910 = (void *) &buf;
      dd.address = D.910;

Your structure constructor,  DD = descr(c_loc(buf)),  gives:
      struct descr descr.2;
      descr.2.address = 0B;


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |wrong-code
   Last reconfirmed|0000-00-00 00:00:00         |2008-04-20 11:40:52
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983

[Bug fortran/35983] C_LOC in derived type constructor gives weird result

[mikael dot morin at tele2 dot fr]

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------- Comment #2 from mikael dot morin at tele2 dot fr  2008-11-05 11:43 -------
There is a reset of the expression to NULL_EXPR in case we encounter c_null_ptr
or c_null_funptr. 
However, the if conditions for this relies on the is_iso_c attribute, which is
the case of c_loc. 
This patch changes this behavior by relying on the symtree names instead. 

Index: trans-expr.c
===================================================================
--- trans-expr.c        (révision 141583)
+++ trans-expr.c        (copie de travail)
@@ -3689,15 +3682,16 @@ gfc_trans_structure_assign (tree dest, gfc_expr *
     {
       /* Skip absent members in default initializers.  */
       if (!c->expr)
-        continue;
+       continue;

       /* Update the type/kind of the expression if it represents either
         C_NULL_PTR or C_NULL_FUNPTR.  This is done here because this may
         be the first place reached for initializing output variables that
         have components of type C_PTR/C_FUNPTR that are initialized.  */
-      if (c->expr->ts.type == BT_DERIVED && c->expr->ts.derived
-         && c->expr->ts.derived->attr.is_iso_c)
-        {
+      if (c->expr->symtree && c->expr->symtree->name
+         && (!strcmp ("c_null_ptr", c->expr->symtree->name)
+             || !strcmp ("c_null_funptr", c->expr->symtree->name)))
+       {
          c->expr->expr_type = EXPR_NULL;
          c->expr->ts.type = c->expr->ts.derived->ts.type;
          c->expr->ts.f90_type = c->expr->ts.derived->ts.f90_type;

With this patch alone, I still get wrong-code though (pointer uninitialized
instead of nullified). 
I've had to revert this patch
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35150#c7
to have it working. 

There is only one regression, c_loc_tests_12.f03. 
That one is expected, and we are back at PR35150. 
I looked at that one too, but I must admit I'm at least as confused as FX when
he fixed it. 
If some middle-end gurus could take a look/give some tips there...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983

[Bug fortran/35983] C_LOC in derived type constructor gives weird result

[mikael at gcc dot gnu dot org]

------- Comment #3 from mikael at gcc dot gnu dot org  2008-12-09 19:13 -------
Subject: Bug 35983

Author: mikael
Date: Tue Dec  9 19:12:27 2008
New Revision: 142605

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142605
Log:
2008-12-09  Mikael Morin  <mikael.morin@tele2.fr>

        PR fortran/35983
        * trans-expr.c (gfc_trans_subcomponent_assign):
        Add se's pre and post blocks to current block.
        (gfc_trans_structure_assign): Remove specific handling
        of C_NULL_PTR and C_NULL_FUNPTR.

2008-12-09  Mikael Morin  <mikael.morin@tele2.fr>

        PR fortran/35983
        * gfortran.dg/pr35983.f90: New test.


Added:
    trunk/gcc/testsuite/gfortran.dg/pr35983.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/trans-expr.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983

[Bug fortran/35983] C_LOC in derived type constructor gives weird result

[mikael at gcc dot gnu dot org]

-- 

mikael at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |mikael at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2008-04-20 11:40:52         |2008-12-09 19:32:41
               date|                            |
   Target Milestone|---                         |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983

[Bug fortran/35983] C_LOC in derived type constructor gives weird result

[mikael at gcc dot gnu dot org]

------- Comment #4 from mikael at gcc dot gnu dot org  2008-12-21 15:07 -------
Subject: Bug 35983

Author: mikael
Date: Sun Dec 21 15:06:15 2008
New Revision: 142860

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142860
Log:
2008-12-21  Mikael Morin  <mikael.morin@tele2.fr>

        PR fortran/35983
        * trans-expr.c (gfc_trans_subcomponent_assign):
        Add se's pre and post blocks to current block.
        (gfc_trans_structure_assign): Remove specific handling
        of C_NULL_PTR and C_NULL_FUNPTR.

2008-12-21  Mikael Morin  <mikael.morin@tele2.fr>

        PR fortran/35983
        * gfortran.dg/pr35983.f90: New test.


Added:
    branches/gcc-4_3-branch/gcc/testsuite/gfortran.dg/pr35983.f90
Modified:
    branches/gcc-4_3-branch/gcc/fortran/ChangeLog
    branches/gcc-4_3-branch/gcc/fortran/trans-expr.c
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983

[Bug fortran/35983] C_LOC in derived type constructor gives weird result

[mikael at gcc dot gnu dot org]

------- Comment #5 from mikael at gcc dot gnu dot org  2008-12-21 15:10 -------
Fixed on trunk(4.4) and 4.3.
Thanks for the report.


-- 

mikael at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35983