Re: [rfa:solib] Handle start-address descriptors

[Andrew Cagney <ac131313@redhat.com>]

> On Oct 27,  1:45pm, Andrew Cagney wrote:
> 
> 
>> Index: solib-svr4.c
> 
> ...
> 
>> +#include "bfd-target.h"
>> +#include "exec.h"
> 
> 
> I'm surprised that you needed to include exec.h.  solib-svr4.c already
> includes target.h and I would've thought this to be sufficient.  If
> exec.h isn't needed, please take it out.  (Don't forget to fix Makefile.in.)

They are both needed.

>> +/* Given an executable's ABFD and target, compute the entry-point
>> +   address.  */
>> +
>> +static CORE_ADDR
>> +exec_entry_point (struct bfd *abfd, struct target_ops *targ)
>> +{
> 
> 
> Could you add a comment here telling why
> gdbarch_convert_from_func_ptr_addr() is needed.  Maybe something like
> this?

I'll add your comment.

>   /* For most targets, the address returned by bfd_get_start_address()
>      is the entry point for the start function.  But, for some targets,
>      bfd_get_start_address() returns the address of a function descriptor
>      from which the entry point address may be extracted.  This address
>      is extracted by gdbarch_convert_from_func_ptr_addr().  The method
>      gdbarch_convert_from_func_ptr_addr() is the merely the identify
>      function for targets which don't use function descriptors.  */
> 
> Hmm, a possible problem...  What happens when the target uses function
> descriptors, but not for the exec file's start address?  I'm wondering
> (ugh) if a separate gdbarch method is required for obtaining the start
> address.

Fortunatly a previous patch addressed that problem.  The convert 
function is only applied to positively identified descriptors.

>> +  return gdbarch_convert_from_func_ptr_addr (current_gdbarch,
>> +					     bfd_get_start_address (abfd),
>> +					     targ);
>> +}

Andrew