Bug 41022 - [F03] procedure pointer components as actual arguments
Summary: [F03] procedure pointer components as actual arguments
Alias: None
Product: gcc
Classification: Unclassified
Component: fortran (show other bugs)
Version: 4.5.0
: P3 normal
Target Milestone: ---
Assignee: janus
Keywords: wrong-code
Depends on:
Reported: 2009-08-10 10:11 UTC by Juergen Reuter
Modified: 2009-08-12 19:21 UTC (History)
1 user (show)

See Also:
Host: Linux 32bit, 64bit, MAC OS X
Target: fortran 4.5.0
Build: Ref. svn r150253
Known to work:
Known to fail: 4.5.0
Last reconfirmed: 2009-08-10 12:46:47

Example file which shows the PP problem (260 bytes, text/x-fortran)
2009-08-10 10:12 UTC, Juergen Reuter

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Description Juergen Reuter 2009-08-10 10:11:35 UTC
It seems that not a pointer is transferred but a value in the following case.
Here is the tracking info:

gfortran -g fptr_transfer.f90 -o fptr_transfer && ./fptr_transfer
Segmentation fault (core dumped)gdb fptr_transfer core
Program terminated with signal 11, Segmentation fault.
#0  0x0000000000400629 in assign_proc_ptr (ptr=0x0, obj1=( 0x40060c <proc> 
)) at fptr_transfer.f90:32
32          ptr => obj1%proc
(gdb) where
#0  0x0000000000400629 in assign_proc_ptr (ptr=0x0, obj1=( 0x40060c <proc> 
)) at fptr_transfer.f90:32
#1  0x0000000000400687 in transfer_proc_ptr (obj2=( 0 ), obj1=( 0x40060c 
<proc> )) at fptr_transfer.f90:26
#2  0x000000000040064c in foo () at fptr_transfer.f90:19
#3  0x00000000004006c2 in main (argc=1, argv=0x7ffff12d2fe4 
'./fptr_transfer\000') at fptr_transfer.f90:19
#4  0x00007f1d9cdf0586 in __libc_start_main () from /lib64/libc.so.6
#5  0x0000000000400549 in _start () at ../sysdeps/x86_64/elf/start.S:113
Current language:  auto; currently fortran

Here is the corresponding code:
subroutine proc ()
end subroutine proc

program foo

      subroutine proc ()
      end subroutine proc
   end interface

   type :: container_t
      procedure(proc), nopass, pointer :: proc => null ()
   end type container_t

   type(container_t), target :: obj1
   type(container_t) :: obj2

   obj1%proc => proc
   call transfer_proc_ptr (obj2, obj1)


   subroutine transfer_proc_ptr (obj2, obj1)
     type(container_t), intent(out) :: obj2
     type(container_t), intent(in), target :: obj1
     call assign_proc_ptr (obj2%proc, obj1)
   end subroutine transfer_proc_ptr

   subroutine assign_proc_ptr (ptr, obj1)
     procedure(proc), pointer :: ptr
     type(container_t), intent(in), target :: obj1
     ptr => obj1%proc
   end subroutine assign_proc_ptr

end program foo
Comment 1 Juergen Reuter 2009-08-10 10:12:25 UTC
Created attachment 18335 [details]
Example file which shows the PP problem
Comment 2 janus 2009-08-10 12:46:47 UTC
Confirmed. -fdump-tree-original shows:

assign_proc_ptr (void (*<T63>) (void) * ptr, struct container_t & obj1)
  *ptr = obj1->proc;
Comment 3 janus 2009-08-10 13:41:25 UTC
Actually the part of the dump shown in comment #2 is ok. The problematic piece is this:

transfer_proc_ptr (struct container_t & obj2, struct container_t & obj1)
  assign_proc_ptr (obj2->proc, (struct container_t *) obj1);

Here the obj2->proc is missing an "&".
Comment 4 janus 2009-08-10 13:49:35 UTC
This problems seems to be similar to PR 40450.
Comment 5 janus 2009-08-10 14:14:12 UTC
This patchlet should fix it:

Index: gcc/fortran/trans-expr.c
--- gcc/fortran/trans-expr.c	(revision 150621)
+++ gcc/fortran/trans-expr.c	(working copy)
@@ -2679,7 +2679,8 @@ gfc_conv_procedure_call (gfc_se * se, gf
 			   && fsym->attr.flavor != FL_PROCEDURE)
 			  || (fsym->attr.proc_pointer
 			      && !(e->expr_type == EXPR_VARIABLE
-			      && e->symtree->n.sym->attr.dummy))))
+			      && e->symtree->n.sym->attr.dummy))
+			  || gfc_is_proc_ptr_comp (e, NULL)))
 		      /* Scalar pointer dummy args require an extra level of
 			 indirection. The null pointer already contains
Comment 6 janus 2009-08-11 20:08:51 UTC
Subject: Bug 41022

Author: janus
Date: Tue Aug 11 20:08:35 2009
New Revision: 150665

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=150665
2009-08-11  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/41022
	* trans-expr.c (gfc_conv_procedure_call): Handle procedure pointer
	components as actual arguments.

2009-08-11  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/41022
	* gfortran.dg/proc_ptr_comp_14.f90: New.


Comment 7 janus 2009-08-11 20:15:10 UTC
Fixed with r150665. Thanks for the report.
Comment 8 Juergen Reuter 2009-08-12 19:09:47 UTC
The fix seems not to work with the test program. 
On Linux 32 bit I get the following when compiling:
/tmp/cciQlmr1.o: In function `MAIN__':
foo.f90:(.text+0x1b): undefined reference to `proc_'
collect2: ld returned 1 exit status

and on MAC OS X:
Undefined symbols:
  "_proc_", referenced from:
      _proc_$non_lazy_ptr in ccJFt47G.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
Comment 9 Juergen Reuter 2009-08-12 19:21:52 UTC
Sorry, false alarm. Had a truncated test file.