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Commit: Fix display of DW_FORM_ref8 attribute values

Tristan Gingold gingold@adacore.com
Wed Oct 9 15:57:00 GMT 2013 
On Oct 9, 2013, at 4:04 PM, Nick Clifton <nickc@redhat.com> wrote:

> Hi Guys,
> 
>  I am checking in the patch below to fix the display of DWARF
>  DW_FORM_ref8 attributes.  The code was not biasing the display value
>  with the start of the CU containing the reference.
> 
>  Tested on 32-bit and 64-bit hosts with a wide variety of different
>  targets - no regressions.
> 
>  Tristan - is this patch OK for the 2.24 branch ?

Sure.

Tristan.

> 
> Cheers
>  Nick
> 
> binutils/ChangeLog
> 2013-10-09  Nick Clifton  <nickc@redhat.com>
> 
> 	* dwarf.c (add64): New function.
> 	(read_and_display_attr_value): Add CU offset in to the value
> 	displayed for a DW_AT_ref8 attribute.
> 
> Index: binutils/dwarf.c
> ===================================================================
> RCS file: /cvs/src/src/binutils/dwarf.c,v
> retrieving revision 1.140
> diff -u -3 -p -r1.140 dwarf.c
> --- binutils/dwarf.c	1 Oct 2013 10:32:54 -0000	1.140
> +++ binutils/dwarf.c	9 Oct 2013 14:05:30 -0000
> @@ -1425,6 +1425,34 @@ find_cu_tu_set_v2 (dwarf_vma cu_offset, 
>   return NULL;
> }
> 
> +/* Add INC to HIGH_BITS:LOW_BITS.  */
> +static void
> +add64 (dwarf_vma * high_bits, dwarf_vma * low_bits, dwarf_vma inc)
> +{
> +  dwarf_vma tmp = * low_bits;
> +
> +  tmp += inc;
> +
> +  /* FIXME: There is probably a better way of handling this:
> +
> +     We need to cope with dwarf_vma being a 32-bit or 64-bit
> +     type.  Plus regardless of its size LOW_BITS is meant to
> +     only hold 32-bits, so if there is overflow or wrap around
> +     we must propagate into HIGH_BITS.  */
> +  if (tmp < * low_bits)
> +    {
> +      ++ * high_bits;
> +    }
> +  else if (sizeof (tmp) > 8
> +	   && (tmp >> 31) > 1)
> +    {
> +      ++ * high_bits;
> +      tmp &= 0xFFFFFFFF;
> +    }
> +
> +  * low_bits = tmp;
> +}
> +
> static unsigned char *
> read_and_display_attr_value (unsigned long attribute,
> 			     unsigned long form,
> @@ -1567,15 +1595,17 @@ read_and_display_attr_value (unsigned lo
> 
>     case DW_FORM_ref8:
>     case DW_FORM_data8:
> -      if (!do_loc)
> 	{
> 	  dwarf_vma high_bits;
> +	  dwarf_vma utmp;
> 	  char buf[64];
> 
> 	  SAFE_BYTE_GET64 (data, &high_bits, &uvalue, end);
> -
> +	  utmp = uvalue;
> +	  if (form == DW_FORM_ref8)
> +	    add64 (& high_bits, & utmp, cu_offset);
> 	  printf (" 0x%s",
> -		  dwarf_vmatoa64 (high_bits, uvalue, buf, sizeof (buf)));
> +		  dwarf_vmatoa64 (high_bits, utmp, buf, sizeof (buf)));
> 	}
> 
>       if ((do_loc || do_debug_loc || do_debug_ranges)
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