Re: [gfortran] ICE with common blocks

[canqun at nudt dot edu dot cn]

Paul Brook <paul@nowt.org>:

> Patch below fixes an ICE when using COMMON blocks in 
modules. We were trying
>  
> to explicity create a variable from the symbol for 
the common block iteslf.
> 
> Tested on i686-linux
> Applied to tree-ssa branch.
> 
> Paul

I supplied another patch to generate backend 
declarations for COMMON variables and EQUIVALENCE 
objects defind in MODULE. But part of the testcase I 
attached still can not be passed. It seems there is 
much work to do.

Canqun Yang.


Below is the ChangeLog entry.

2003-11-26  Canqun Yang  <canqun@nudt.edu.cn>

	* trans-decl.c (gfc_get_symbol_decl): 
Register the backend_decl for
	COMMON variable or EQUIVALENCE object.
	(gfc_create_module_variable): Skip COMMON 
variables and EQUIVALENCE
	objects.
	(gfc_generate_module_vars): Translate 
EQUIVALENCE lists and COMMON
	blocks.

*** t.c	2003-11-26 11:54:26.000000000 +0800
--- trans-decl.c	2003-11-26 11:51:21.000000000 +0800
*************** gfc_get_symbol_decl (gfc_symbol * sym)
*** 728,733 ****
--- 728,734 ----
               are part of a common block.  */
            gfc_todo_error ("CHARACTER inside COMMON or EQUIVALENCE");
  	}
+       sym->backend_decl = decl;
        return decl;
      }
  
*************** gfc_create_module_variable (gfc_symbol *
*** 1679,1684 ****
--- 1680,1689 ----
    /* Create the decl.  */
    decl = gfc_get_symbol_decl (sym);
  
+   /* Skip COMMON variables and EQUIVALENCE objects.  */
+   if (sym->addr_base)
+     return;
+ 
    /* We want to allocate storage for this variable.  */
    TREE_STATIC (decl) = 1;
  
*************** gfc_generate_module_vars (gfc_namespace 
*** 1735,1740 ****
--- 1740,1751 ----
    /* Check the frontend left the namespace in a reasonable state.  */
    assert (ns->proc_name && !ns->proc_name->tlink);
  
+   /* Translate EQUIVALENCE lists.   */
+   gfc_trans_equivalence (ns);
+ 
+   /* Translate COMMON blocks.  */
+   gfc_trans_common (ns);
+ 
    /* Create decls for all the module varuiables.  */
    gfc_traverse_ns (ns, gfc_create_module_variable);
  }



! Generate proper backend declarations for COMMON variables and EQUIVALENCE
! objects defined in a MODULE.
module m
   real (kind=8) a(8)
   real (kind=8) b(5), c(5)
   common /com1/b,c
   equivalence (a(1), b(2))

contains
   subroutine suba
      b = 100
      c = 200
   end subroutine
end module m

program module_common
  use m
  call suba ()
  if (any (b .ne. 100) .or. any (c .ne. 200)) call abort

! Can not pass. The address of a(4) should be com1_ + 32
! if ((a(4) .ne. 100) .or. (a(5) .ne. 200)) call abort
   
   call subb ()
   call subc ()

contains
   subroutine subb
! Can not pass. The reference of a, b, c should be com1_ + offset
!     if (any (b .ne. 100) .or. any (c .ne. 200)) call abort
!     if ((a (4) .ne. 100) .or. (a(5) .ne. 200)) call abort
   end subroutine
end

subroutine subc
   real (kind=8) a(8)
   real (kind=8) b(5), c(5)
   common /com1/b,c
   equivalence (a(1), b(2))
   if ((a (4) .ne. 100) .or. (a(5) .ne. 200)) call abort
end subroutine