Re: gdb.mi/mi-cli.exp failures

Nick Clifton
2003-04-02T17:06:18Z

Hi Daniel,

> 1. stabs.c can create a new section while reading stabs from an input
> BFD. This means that I can't save and restore a per-section datum
> (output_offset and output_section) around a call to
> bfd_link_add_symbols.
>
> #0 bfd_section_init (abfd=0x8277980, newsect=0x827b9b4) at /opt/src/gdb/src/bfd/section.c:734
> #1 0x0818039d in _bfd_link_section_stabs (abfd=0x8277980, psinfo=0x827855c, stabsec=0x827cae8,
> stabstrsec=0x827cb7c, psecinfo=0x827b9c0) at /opt/src/gdb/src/bfd/stabs.c:240
> #2 0x081501d6 in elf_link_add_object_symbols (abfd=0x8277980, info=0xbfffe0b0)
> at /opt/src/gdb/src/bfd/elflink.h:2305
> #3 0x08148f8b in bfd_simple_get_relocated_section_contents (abfd=0x8277980, sec=0x827cae8,
> outbuf=0x828f868 "", symbol_table=0x0) at /opt/src/gdb/src/bfd/simple.c:247
>
> It's doing this:
> sinfo->stabstr = bfd_make_section_anyway (abfd, ".stabstr");
> which doesn't make much sense to me; there's _already_ a section named
> .stabstr in the executable, why not use that one?

Hmm, agreed - this probably ought to be a call to
bfd_get_section_by_name(). And if that fails then the code should try
to find the output bfd and create the section there. (Either that or
else return a failure result. Can you have a .stabs section without a
.stabsstr section ?)

> Can I not rely on section_count remaining stable for an input BFD?

I think that you ought to be able to rely on this.

> 2. We call bfd_simple_get_relocated_section_contents twice on the same
> section. The second time, it crashes. It appears that pointers to the
> symbol table are stored in the canonicalized relocations, in
> elf_slurp_reloc_table_from_section. This means that the symbol table
> can no longer be freed. Should it be allocated via bfd_alloc instead
> of bfd_malloc?

> Note that this is a significant change, since we're talking about the
> pointer table, i.e. the area of size bfd_get_symtab_upper_bound ().

Plus we would now have to ensure that the caller has allocated the
memory in the same bfd, it is passing in the 'symbol_table' pointer.

However, since the relocs are persistent, I think that the symbols
that they use need to be persistent too. Hence we need to use
bfd_alloc.

Cheers
Nick