Re: [PATCH, gdbserver] Further cleanup of FDPIC/DSBT divergences

[Luis Machado <lgustavo at codesourcery dot com>]

Hi,

On 08/09/2013 09:32 PM, Yao Qi wrote:
> On 08/10/2013 01:20 AM, Luis Machado wrote:
> > +/* Scan for DYNTAG in .dynamic section of ABFD.  If DYNTAG is found 1
> > +   is returned and the corresponding PTR is set.  We only search in
> > +   the BFD, not in the target's memory.  */
> > +
> > +static int
> > +scan_dyntag_in_bfd (int dyntag, bfd *abfd, CORE_ADDR *ptr)
>
> Luis,
> We've already have a function scan_dyntag in solib-dsbt.c which reads
> in both BFD and the target memory.  There are some duplications in
> scan_dyntag and scan_dyntag_in_bfd.  We can combine them into one
> function, probably.

I seem to recall the code to read target memory, in the case of targets 
that do relocations based on loadmaps, get this information wrong, based 
on past experience with a different DSBT-based target.

From what i recall, it tries to read the dsbt_index from the main 
executable's .dynamic, but the information is in the solib's .dynamic 
section.

I can't be sure it works for c6x since there is no target for me to test 
on. If someone has access to that, i can coordinate some testing. This 
is the biggest problem right now.

> > +/* Given a shared library filename, load it up and find
> > +   out what is its dsbt index.  */
> > +
> > +static int
> > +fetch_solib_dsbt_index (const char *filename)
> > +{
> > +  unsigned long dsbt_index;
> > +  CORE_ADDR addr;
> > +  bfd *solib_bfd = NULL;
> > +  volatile struct gdb_exception ex;
> > +
> > +  if (filename == NULL)
> > +    return -1;
> > +
> > +  /* Open the shared library.  */
> > +  TRY_CATCH (ex, RETURN_MASK_ALL)
> > +    {
> > +      solib_bfd = solib_bfd_open ((char *) filename);
> > +    }
> > +  if (solib_bfd == NULL)
> > +    {
> > +      return -1;
> > +    }
>
> Unnecessary braces.

Fixed.

> > +
> > +  /* Fetch the DSBT_INDEX from the shared library file on disk.  */
> > +  if (scan_dyntag_in_bfd (DT_TIC6X_DSBT_INDEX, solib_bfd, &addr) == 0)
>
> I don't find the definition of DT_TIC6X_DSBT_INDEX.  In uclibc, I only
> find DT_C6000_DSBT_INDEX.

That is exactly what it is. I named it DT_TIC6X_DSBT_INDEX to make it 
more meaningful, but i can use DT_C6000_DSBT_INDEX without problems i think.