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Re: [RFA] Better support for DWARF location blocks (was DWARF support for .debug_loc offsets)


Looks good --- please commit.  Thank you!

But --- could you make a function attr_form_is_block that takes an
attribute and returns true if its form is one of the DW_FORM_block*
forms, and use that instead of writing out the list each time?

Petr Sorfa <petrs@caldera.com> writes:

> Hi,
> 
> This patch provides better error detection when processing certain DWARF
> location blocks. Basically an error is given in these cases when the
> attribute's form is not a DW_AT_block*.
> 
> Again, this patch does not support in read_tag_string_type() the
> DW_AT_string_length attribute which is currently being misused by GCC
> (it uses it to hold the length, rather than the location to the length)
> and GDB supports this incorrect form.
> 
> 2002-07-11 Petr Sorfa (petrs@caldera.com)
> 
>         *  dwarf2read.c (dwarf2_invalid_attrib_class): New
>            complaint for invalid attribute class or form.
>            (read_func_scope): DW_AT_frame_base
>            better handling of DW_AT_block*.
>            (dwarf2_add_member_fn): DW_AT_vtable_elem_location
>            better handling of DW_AT_block*.
>            (read_common_block): DW_AT_location
>            better handling of DW_AT_block*.
>            (read_partial_die): DW_AT_location better handling
>            of DW_AT_block*.
>            (new_symbol): DW_AT_external better handling of
>            DW_AT_block*. Proper initialization of variable
>            "addr".Index: dwarf2read.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/dwarf2read.c,v
> retrieving revision 1.60
> diff -c -p -r1.60 dwarf2read.c
> *** dwarf2read.c	22 Jun 2002 00:05:59 -0000	1.60
> --- dwarf2read.c	11 Jul 2002 20:03:34 -0000
> *************** static struct complaint dwarf2_macro_spa
> *** 658,663 ****
> --- 658,667 ----
>   {
>     "macro definition contains spaces in formal argument list:\n`%s'", 0, 0
>   };
> + static struct complaint dwarf2_invalid_attrib_class =
> + {
> +   "invalid attribute class or form for '%s' in '%s'", 0, 0
> + };
>   
>   /* local function prototypes */
>   
> *************** read_func_scope (struct die_info *die, s
> *** 1870,1876 ****
>     attr = dwarf_attr (die, DW_AT_frame_base);
>     if (attr)
>       {
> !       CORE_ADDR addr = decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
>         if (isderef)
>   	complain (&dwarf2_unsupported_at_frame_base, name);
>         else if (isreg)
> --- 1874,1900 ----
>     attr = dwarf_attr (die, DW_AT_frame_base);
>     if (attr)
>       {
> !       CORE_ADDR addr;
> ! 
> !       /* Support the .debug_loc offsets */
> !       if (attr->form == DW_FORM_block1
> !                        || attr->form == DW_FORM_block2
> !                        || attr->form == DW_FORM_block4
> !                        || attr->form == DW_FORM_block)
> !         {
> !           addr = decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
> !         }
> !       else if (attr->form == DW_FORM_data4 || attr->form == DW_FORM_data8)
> !         {
> !           complain (&dwarf2_complex_location_expr);
> !           addr = 0;
> !         }
> !       else
> !         {
> !           complain (&dwarf2_invalid_attrib_class, "DW_AT_frame_base", name);
> !           addr = 0;
> !         }
> !     
>         if (isderef)
>   	complain (&dwarf2_unsupported_at_frame_base, name);
>         else if (isreg)
> *************** dwarf2_add_member_fn (struct field_info 
> *** 2348,2354 ****
>     /* Get index in virtual function table if it is a virtual member function.  */
>     attr = dwarf_attr (die, DW_AT_vtable_elem_location);
>     if (attr)
> !     fnp->voffset = decode_locdesc (DW_BLOCK (attr), objfile, cu_header) + 2;
>   }
>   
>   /* Create the vector of member function fields, and attach it to the type.  */
> --- 2372,2396 ----
>     /* Get index in virtual function table if it is a virtual member function.  */
>     attr = dwarf_attr (die, DW_AT_vtable_elem_location);
>     if (attr)
> !     {
> !       /* Support the .debug_loc offsets */
> !       if (attr->form == DW_FORM_block1
> !                        || attr->form == DW_FORM_block2
> !                        || attr->form == DW_FORM_block4
> !                        || attr->form == DW_FORM_block)
> !         {
> !           fnp->voffset = decode_locdesc (DW_BLOCK (attr), objfile, cu_header) + 2;
> !         }
> !       else if (attr->form == DW_FORM_data4 || attr->form == DW_FORM_data8)
> !         {
> !           complain (&dwarf2_complex_location_expr);
> !         }
> !       else
> !         {
> !           complain (&dwarf2_invalid_attrib_class, "DW_AT_vtable_elem_location",
> !                     fieldname);
> !         }
> !    }
>   }
>   
>   /* Create the vector of member function fields, and attach it to the type.  */
> *************** read_common_block (struct die_info *die,
> *** 2812,2818 ****
>     attr = dwarf_attr (die, DW_AT_location);
>     if (attr)
>       {
> !       base = decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
>       }
>     if (die->has_children)
>       {
> --- 2854,2876 ----
>     attr = dwarf_attr (die, DW_AT_location);
>     if (attr)
>       {
> !       /* Support the .debug_loc offsets */
> !       if (attr->form == DW_FORM_block1
> !                        || attr->form == DW_FORM_block2
> !                        || attr->form == DW_FORM_block4
> !                        || attr->form == DW_FORM_block)
> !         {
> !           base = decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
> !         }
> !       else if (attr->form == DW_FORM_data4 || attr->form == DW_FORM_data8)
> !         {
> !           complain (&dwarf2_complex_location_expr);
> !         }
> !       else
> !         {
> !           complain (&dwarf2_invalid_attrib_class, "DW_AT_location",
> !                     "common block member");
> !         }
>       }
>     if (die->has_children)
>       {
> *************** read_partial_die (struct partial_die_inf
> *** 3458,3464 ****
>   	  part_die->highpc = DW_ADDR (&attr);
>   	  break;
>   	case DW_AT_location:
> ! 	  part_die->locdesc = DW_BLOCK (&attr);
>   	  break;
>   	case DW_AT_language:
>   	  part_die->language = DW_UNSND (&attr);
> --- 3516,3538 ----
>   	  part_die->highpc = DW_ADDR (&attr);
>   	  break;
>   	case DW_AT_location:
> !           /* Support the .debug_loc offsets */
> !           if (attr.form == DW_FORM_block1
> !                        || attr.form == DW_FORM_block2
> !                        || attr.form == DW_FORM_block4
> !                        || attr.form == DW_FORM_block)
> !             {
> ! 	       part_die->locdesc = DW_BLOCK (&attr);
> !             }
> !           else if (attr.form == DW_FORM_data4 || attr.form == DW_FORM_data8)
> !             {
> !               complain (&dwarf2_complex_location_expr);
> !             }
> !           else
> !             {
> !               complain (&dwarf2_invalid_attrib_class, "DW_AT_location",
> !                         "partial symbol information");
> !             }
>   	  break;
>   	case DW_AT_language:
>   	  part_die->language = DW_UNSND (&attr);
> *************** new_symbol (struct die_info *die, struct
> *** 4522,4528 ****
>     char *name;
>     struct attribute *attr = NULL;
>     struct attribute *attr2 = NULL;
> !   CORE_ADDR addr;
>   
>     name = dwarf2_linkage_name (die);
>     if (name)
> --- 4596,4602 ----
>     char *name;
>     struct attribute *attr = NULL;
>     struct attribute *attr2 = NULL;
> !   CORE_ADDR addr = 0;
>   
>     name = dwarf2_linkage_name (die);
>     if (name)
> *************** new_symbol (struct die_info *die, struct
> *** 4606,4613 ****
>   	      attr2 = dwarf_attr (die, DW_AT_external);
>   	      if (attr2 && (DW_UNSND (attr2) != 0))
>   		{
> ! 		  SYMBOL_VALUE_ADDRESS (sym) =
> ! 		    decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
>   		  add_symbol_to_list (sym, &global_symbols);
>   
>   		  /* In shared libraries the address of the variable
> --- 4680,4704 ----
>   	      attr2 = dwarf_attr (die, DW_AT_external);
>   	      if (attr2 && (DW_UNSND (attr2) != 0))
>   		{
> !                   /* Support the .debug_loc offsets */
> !                   if (attr->form == DW_FORM_block1
> !                        || attr->form == DW_FORM_block2
> !                        || attr->form == DW_FORM_block4
> !                        || attr->form == DW_FORM_block)
> !                     {
> ! 		      SYMBOL_VALUE_ADDRESS (sym) =
> ! 		        decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
> !                     }
> !                   else if (attr->form == DW_FORM_data4
> !                            || attr->form == DW_FORM_data8)
> !                     {
> !                       complain (&dwarf2_complex_location_expr);
> !                     }
> !                   else
> !                     {
> !                       complain (&dwarf2_invalid_attrib_class, "DW_AT_location",
> !                                 "external variable");
> !                     }
>   		  add_symbol_to_list (sym, &global_symbols);
>   
>   		  /* In shared libraries the address of the variable
> *************** new_symbol (struct die_info *die, struct
> *** 4630,4637 ****
>   		}
>   	      else
>   		{
> ! 		  SYMBOL_VALUE (sym) = addr =
> ! 		    decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
>   		  add_symbol_to_list (sym, list_in_scope);
>   		  if (optimized_out)
>   		    {
> --- 4721,4746 ----
>   		}
>   	      else
>   		{
> !                   /* Support the .debug_loc offsets */
> !                   if (attr->form == DW_FORM_block1
> !                        || attr->form == DW_FORM_block2
> !                        || attr->form == DW_FORM_block4
> !                        || attr->form == DW_FORM_block)
> !                     {
> ! 		      SYMBOL_VALUE (sym) = addr =
> ! 		        decode_locdesc (DW_BLOCK (attr), objfile, cu_header);
> !                     }
> !                   else if (attr->form == DW_FORM_data4
> !                            || attr->form == DW_FORM_data8)
> !                     {
> !                       complain (&dwarf2_complex_location_expr);
> !                     }
> !                   else
> !                     {
> !                       complain (&dwarf2_invalid_attrib_class, "DW_AT_location",
> !                                 "external variable");
> !                       addr = 0;
> !                     }
>   		  add_symbol_to_list (sym, list_in_scope);
>   		  if (optimized_out)
>   		    {


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