Re: Regenerate config/features/rs6000

["Anmol P. Paralkar" <b07584 at freescale dot 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.