[PATCH RESEND] gdb/hppa: guess g packet size

[Helge Deller]

On 11/1/25 09:05, Sven Schnelle wrote:
> With qemu supporting 64 bit now, add some code to determine the
> register size of a hppa remote target.
> 
> Signed-off-by: Sven Schnelle <svens@stackframe.org>

Tested-by: Helge Deller <deller@gmx.de>

Helge


> ---
>   gdb/hppa-tdep.c | 46 +++++++++++++++++++++++++++++++++++++++++-----
>   1 file changed, 41 insertions(+), 5 deletions(-)
> 
> diff --git a/gdb/hppa-tdep.c b/gdb/hppa-tdep.c
> index 96cb797c023..ca59fc63d1d 100644
> --- a/gdb/hppa-tdep.c
> +++ b/gdb/hppa-tdep.c
> @@ -33,6 +33,8 @@
>   #include "trad-frame.h"
>   #include "frame-unwind.h"
>   #include "frame-base.h"
> +#include "remote.h"
> +#include "target-descriptions.h"
>   
>   #include "gdbcore.h"
>   #include "cli/cli-cmds.h"
> @@ -43,6 +45,14 @@
>   
>   static bool hppa_debug = false;
>   
> +/* Properties (for struct target_desc) describing the g/G packet
> +   layout.  */
> +#define PROPERTY_GP32 "internal: transfers-32bit-registers"
> +#define PROPERTY_GP64 "internal: transfers-64bit-registers"
> +
> +struct target_desc *hppa_tdesc32;
> +struct target_desc *hppa_tdesc64;
> +
>   /* Some local constants.  */
>   static const int hppa32_num_regs = 128;
>   static const int hppa64_num_regs = 96;
> @@ -2978,6 +2988,17 @@ hppa_skip_trampoline_code (const frame_info_ptr &frame, CORE_ADDR pc)
>   
>      -- chastain 2003-12-18  */
>   
> +static void
> +hppa_register_g_packet_guesses (struct gdbarch *gdbarch)
> +{
> +  /* If the size matches the set of 32-bit or 64-bit integer registers,
> +     assume that's what we've got.  */
> +  register_remote_g_packet_guess (gdbarch, hppa32_num_regs * 4, hppa_tdesc32);
> +  register_remote_g_packet_guess (gdbarch, hppa64_num_regs * 8, hppa_tdesc64);
> +
> +  /* Otherwise we don't have a useful guess.  */
> +}
> +
>   static struct gdbarch *
>   hppa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>   {
> @@ -2991,14 +3012,24 @@ hppa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>       = gdbarch_alloc (&info, gdbarch_tdep_up (new hppa_gdbarch_tdep));
>     hppa_gdbarch_tdep *tdep = gdbarch_tdep<hppa_gdbarch_tdep> (gdbarch);
>   
> -  /* Determine from the bfd_arch_info structure if we are dealing with
> -     a 32 or 64 bits architecture.  If the bfd_arch_info is not available,
> -     then default to a 32bit machine.  */
> -  if (info.bfd_arch_info != NULL)
> +  /* Determine from the target description if we are dealing with
> +     a 32 or 64 bits architecture. If the target description is not
> +     available, then check whether bfd_arch_info could be used.
> +     Otherwise default to a 32bit machine.
> +  */
> +  if (info.target_desc != NULL) {
> +    if (tdesc_property (info.target_desc, PROPERTY_GP64) != NULL)
> +      tdep->bytes_per_address = 8;
> +    else if (tdesc_property (info.target_desc, PROPERTY_GP32) != NULL)
> +      tdep->bytes_per_address = 4;
> +  } else if (info.bfd_arch_info != NULL) {
>       tdep->bytes_per_address =
>         info.bfd_arch_info->bits_per_address / info.bfd_arch_info->bits_per_byte;
> -  else
> +  } else {
>       tdep->bytes_per_address = 4;
> +  }
> +
> +  hppa_register_g_packet_guesses (gdbarch);
>   
>     tdep->find_global_pointer = hppa_find_global_pointer;
>   
> @@ -3122,6 +3153,11 @@ hppa_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
>   INIT_GDB_FILE (hppa_tdep)
>   {
>     gdbarch_register (bfd_arch_hppa, hppa_gdbarch_init, hppa_dump_tdep);
> +  hppa_tdesc32 = allocate_target_description ().release ();
> +  set_tdesc_property (hppa_tdesc32, PROPERTY_GP32, "");
> +
> +  hppa_tdesc64 = allocate_target_description ().release ();
> +  set_tdesc_property (hppa_tdesc64, PROPERTY_GP64, "");
>   
>     add_cmd ("unwind", class_maintenance, unwind_command,
>   	   _("Print unwind table entry at given address."),