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Re: [RFA] Better support for DWARF location blocks (was DWARF support for .debug_loc offsets)
- From: Jim Blandy <jimb at redhat dot com>
- To: Petr Sorfa <petrs at caldera dot com>
- Cc: "gdb-patches at sources dot redhat dot com" <gdb-patches at sources dot redhat dot com>
- Date: 12 Jul 2002 11:04:28 -0500
- Subject: Re: [RFA] Better support for DWARF location blocks (was DWARF support for .debug_loc offsets)
- References: <3D2DE995.BE7DA3B4@caldera.com>
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)
> {