Re: Dwarf2-related Internal error

[Michal Ludvig <mludvig at suse dot cz>]

Michal Ludvig told me that:
> OK, I have found the problem. The type of the parameter 'xx' is an array 
> with unspecified size. Lower bound is set to '1' for Fortran and since 
> there is no upper bound specified, it's set to '-1' by default.
>
> 3097     else if (attr->form == DW_FORM_block1)
> 3098     {
> 3099       /* GCC encodes arrays with unspecified or dynamic length
> 3100          with a DW_FORM_block1 attribute.
> 3101          FIXME: GDB does not yet know how to handle dynamic
> 3102          arrays properly, treat them as arrays with unspecified
> 3103          length for now.  */
> 3104       high = -1;
> 3105     }
>
> Later, when the actual size of the array type is computed, it takes the 
> size of the main type (real, size=4) and multiplies it by 
> (high-low+1=-1) leading to -4 which is quite a big number when converted 
> to unsigned.
>
> Now how to solve it. For now I did
>
>                      length for now.  */
>                   high = -1;
> +                 if (cu_language == language_fortran)
> +                   high = 0;
>                 }
>
> which at least prevents GDB from crashing. IMHO it achieves the same 
> behaviour as for other languages, where low=0, high=-1 and so the size 
> of the array results to 0. In fortran low=1, so with high=0 the size 
> will become 0 as well.
>
> Would this be an acceptable solution? Any comments?

PING!
http://sources.redhat.com/ml/gdb/2003-08/msg00150.html

Any comments? Tha patch is attached. It proved to work pretty well - can 
I apply it?

Thanks!

Michal Ludvig
--
SuSE CR, s.r.o             mludvig@suse.cz | I would like to change
(+420) 296.545.373      http://www.suse.cz | the world, but they wont
Personal homepage http://www.logix.cz/~mic | tell me the source code.

2003-09-17  Michal Ludvig  <mludvig@suse.cz>

	* dwarf2read.c (read_array_type): Set upper bound for
	Fortran arrays of unspecified size.

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.105
diff -u -p -r1.105 dwarf2read.c
--- dwarf2read.c	15 Sep 2003 17:19:23 -0000	1.105
+++ dwarf2read.c	17 Sep 2003 10:53:35 -0000
@@ -3239,6 +3239,8 @@ read_array_type (struct die_info *die, s
 		     arrays properly, treat them as arrays with unspecified
 		     length for now.  */
 		  high = -1;
+		  if (cu_language == language_fortran)
+		    high = 0;
 		}
 	      else
 		{