relocations when doing file command at gdb prompt

[Roland Puntaier <Roland dot Puntaier at br-automation dot com>]

Hi,

maybe someone can help me.

The Problem
-----------
I try to remote debug an embedded device with gdb.
(gdb) target remote XXX
I found that in 
    remote.c:
        get_offsets(){...
    objfiles.c:
        objfile_relocate(){...
l->item[i].pc is quite out of range.

My investigations so far
------------------------
The pc value comes from the preceeding file command:
(gdb) file -readnow YYY
    dbxread.c:
        process_one_symbol(){...
        function_start_offset = ANOFFSET (section_offsets, 
SECT_OFF_TEXT (objfile));
        ...
        case N_SLINE:...
        valu += function_start_offset;
        ...
        record_line(,,valu);
    buildsym.c:
        record_line(,,pc){...e->pc = ADDR_BITS_REMOVE(pc);
function_start_offset had twice the value it should have when 
compared to objdump output.

The wrong values showed up first in
    bfd/simple.c:
        bfd_simple_get_relocated_section_contents(){...
        contents = bfd_get_relocated_section_contents(){...
    bfd/reloc.c:
        bfd_generic_get_relocated_section_contents (reloc.c:4432){...
        bfd_perform_relocation{...
        symbol = *(reloc_entry->sym_ptr_ptr);
        ...
        relocation = symbol->value;
        ...
        output_base = reloc_target_output_section->vma;
        relocation += output_base + symbol->section->output_offset;
        ...
        DOIT(x);
output_base had a value equal x, such that x got doubled.
x is section_offsets from above.

There is a branch, if symbol->section->output_section==0, that 
makes output_base=0;

symbol->section->output_section gets its value from the 
  bfd_simple_get_relocated_section_contents
  {...bfd_canonicalize_symtab()
          {...elf_slurp_symbol_table (elfcode.h)
              {...bfd_elf_get_elf_syms
                  ...
                  sym->symbol.section = bfd_section_from_elf_index ()
                      {...return elf_elfsections 
(abfd)[index]->bfd_section;
 
And bfd_section->output_section is filled in
  symbol_file_command{...symbol_file_add_main_1{...symbol_file_add{...
  symbol_file_add_from_bfd{...
  symbol_file_add_with_addrs_or_offsets{...
    syms_from_objfile()
       {...elf_symfile_read (elfread.c)
            {...elfstab_build_psymtabs (dbxread.c)
                {...symfile_relocate_debug_section (symfile.c)
                    {...bfd_map_over_sections (abfd, 
symfile_dummy_outputs, NULL);

I first thought to change symfile_dummy_outputs (symfile.c), by replacing
  sectp->output_section = sectp;
with
  sectp->output_section = NULL;

I tried this, but unfortunately later on in 
  bfd_simple_get_relocated_section_contents(simple.c:209),
  (bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);)
which is called immediately afterwards from 
symfile_relocate_debug_section,
output_section is set to section again. This time by bfd and not gdb.

I changed simple_save_output_info to set output_section=NULL.
And now linetable's pc had the value as in the file. 

Question/Goal
-------------
Is there another way to make gdb/bfd consistently relocate symbol
information, when doing the gdb file command? 
The best for me would be to have old_offset relative to the 
beginning of the sections, then objfile_relocate would add 
new_offset-old_offset, where new_offset would be the new address.

regards, Roland