gdb/std-regs.c

/* Builtin frame register, for GDB, the GNU debugger.

   Copyright (C) 2002-2021 Free Software Foundation, Inc.

   Contributed by Red Hat.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "user-regs.h"
#include "frame.h"
#include "gdbtypes.h"
#include "value.h"
#include "gdbarch.h"

static struct value *
value_of_builtin_frame_fp_reg (struct frame_info *frame, const void *baton)
{
  struct gdbarch *gdbarch = get_frame_arch (frame);

  if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0)
    /* NOTE: cagney/2003-04-24: Since the mere presence of "fp" in the
       register name table overrides this built-in $fp register, there
       is no real reason for this gdbarch_deprecated_fp_regnum trickery here.
       An architecture wanting to implement "$fp" as alias for a raw
       register can do so by adding "fp" to register name table (mind
       you, doing this is probably a dangerous thing).  */
    return value_of_register (gdbarch_deprecated_fp_regnum (gdbarch),
			      frame);
  else
    {
      struct type *data_ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
      struct value *val = allocate_value (data_ptr_type);
      gdb_byte *buf = value_contents_raw (val);

      gdbarch_address_to_pointer (gdbarch, data_ptr_type,
				  buf, get_frame_base_address (frame));
      return val;
    }
}

static struct value *
value_of_builtin_frame_pc_reg (struct frame_info *frame, const void *baton)
{
  struct gdbarch *gdbarch = get_frame_arch (frame);

  if (gdbarch_pc_regnum (gdbarch) >= 0)
    return value_of_register (gdbarch_pc_regnum (gdbarch), frame);
  else
    {
      struct type *func_ptr_type = builtin_type (gdbarch)->builtin_func_ptr;
      struct value *val = allocate_value (func_ptr_type);
      gdb_byte *buf = value_contents_raw (val);

      gdbarch_address_to_pointer (gdbarch, func_ptr_type,
				  buf, get_frame_pc (frame));
      return val;
    }
}

static struct value *
value_of_builtin_frame_sp_reg (struct frame_info *frame, const void *baton)
{
  struct gdbarch *gdbarch = get_frame_arch (frame);

  if (gdbarch_sp_regnum (gdbarch) >= 0)
    return value_of_register (gdbarch_sp_regnum (gdbarch), frame);
  error (_("Standard register ``$sp'' is not available for this target"));
}

static struct value *
value_of_builtin_frame_ps_reg (struct frame_info *frame, const void *baton)
{
  struct gdbarch *gdbarch = get_frame_arch (frame);

  if (gdbarch_ps_regnum (gdbarch) >= 0)
    return value_of_register (gdbarch_ps_regnum (gdbarch), frame);
  error (_("Standard register ``$ps'' is not available for this target"));
}

void _initialize_frame_reg ();
void
_initialize_frame_reg ()
{
  /* Frame based $fp, $pc, $sp and $ps.  These only come into play
     when the target does not define its own version of these
     registers.  */
  user_reg_add_builtin ("fp", value_of_builtin_frame_fp_reg, NULL);
  user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg, NULL);
  user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg, NULL);
  user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg, NULL);
}