Re: Regenerate config/features/rs6000

["Anmol P. Paralkar" <b07584@freescale.com>]

On Mon, 31 Mar 2008, Daniel Jacobowitz wrote:

> On Mon, Mar 31, 2008 at 04:58:15PM -0700, Michael Eager wrote:
>> Daniel Jacobowitz wrote:
>>> On Mon, Mar 31, 2008 at 04:01:13PM -0700, Michael Eager wrote:
>>>> How are the C files generated from the xml files?
>>>
>>> It's described in the comments in features/Makefile (you have to set
>>> CFILES and use a specific target).
>>
>> Apparently, there's a circular dependency:  you have to have
>> build a gdb so you can generate the feature file which is needed
>> to build gdb.
>
> Yes, there is.  You've got to add XML support separately from
> requiring the C precompiled features.
>
> -- 
> Daniel Jacobowitz
> CodeSourcery
>

Hello,

  I recently tried this out; perhaps the following sketch helps:

  Assume that you are adding support for 'newarch' (say under powerpc).

  First, "declare" newarch to GDB:

  bfd/archures.c
  .#define bfd_mach_ppc_newarch    newarchval

  bfd/bfd-in2.h
  #define bfd_mach_ppc_newarch    newarchval

  bfd/cpu-powerpc.c
  const bfd_arch_info_type bfd_powerpc_archs[] =
  {
   ...
     &bfd_powerpc_archs[<index of the <newarch> bfd_arch_info_type that you are adding>]
   },
    {
     32, /* 32 bits in a word */
     32, /* 32 bits in an address */
     8,  /* 8 bits in a byte */
     bfd_arch_powerpc,
     bfd_mach_ppc_<newarch>,
     "powerpc",
     "powerpc:<newarch>",
     3,
     FALSE, /* not the default */
     powerpc_compatible,
     bfd_default_scan,
     NULL
   },
  }

  gdb/rs6000-tdep.c

  static struct variant variants[] =
{
    ...
    {"<newarch>", "PowerPC <newarch>", bfd_arch_powerpc,
    bfd_mach_ppc_<newarch>, NULL /* For now this is NULL. we'll change this after we generate gdb/features/rs6000/powerpc-<newarch>.c */,
    ...
}

  Build GDB. Create gdb/features/rs6000/<newarch>.xml

  We are now ready to generate <newarch>.c from <newarch>.xml

  Use the newly built GDB (at this stage you should be able to do a: 'set architecture powerpc:<newarch>' and see the effect with a: 'show architecture').

  cd gdb/features

  gmake GDB=<prefix>/bin/powerpc-linux-gnu-gdb XMLTOC="./rs6000/powerpc-<newarch>.xml" ./rs6000/powerpc-<newarch>.c

  If all goes well, you should have gdb/features/rs6000/powerpc-<newarch>.c now.

  Go back to gdb/rs6000-tdep.c

#include "features/rs6000/powerpc-<newarch>.c"

...

  static struct variant variants[] =
{
    ...
    {"<newarch>", "PowerPC <newarch>", bfd_arch_powerpc,
    bfd_mach_ppc_<newarch>, &tdesc_powerpc_<newarch>,  /* Note! */
    ...
}

...

void
_initialize_rs6000_tdep (void)
{
  ...
  initialize_tdesc_powerpc_<newarch> ();
  ...
}

  That should be it. You should now be able to: 'set tdesc filename <?>/gdb/features/rs6000/<newarch>.xml' ...

Regards,
Anmol.