gdb/std-regs.c

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

   Copyright (C) 2002, 2005 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 2 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, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.  */

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

/* Types that describe the various builtin registers.  */

static struct type *builtin_type_frame_reg;

/* Constructors for those types.  */

static void
build_builtin_type_frame_reg (void)
{
  /* $frame.  */
  if (builtin_type_frame_reg == NULL)
    {
#if 0
      struct frame
      {
	void *base;
      };
#endif
      builtin_type_frame_reg = init_composite_type ("frame", TYPE_CODE_STRUCT);
      append_composite_type_field (builtin_type_frame_reg, "base",
				   builtin_type_void_data_ptr);
    }
}

static struct value *
value_of_builtin_frame_reg (struct frame_info *frame)
{
  struct value *val;
  gdb_byte *buf;
  build_builtin_type_frame_reg ();
  val = allocate_value (builtin_type_frame_reg);
  VALUE_LVAL (val) = not_lval;
  buf = value_contents_raw (val);
  memset (buf, 0, TYPE_LENGTH (value_type (val)));
  /* frame.base.  */
  if (frame != NULL)
    ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
			get_frame_base (frame));
  buf += TYPE_LENGTH (builtin_type_void_data_ptr);
  /* frame.XXX.  */
  return val;
}

static struct value *
value_of_builtin_frame_fp_reg (struct frame_info *frame)
{
  if (DEPRECATED_FP_REGNUM >= 0)
    /* NOTE: cagney/2003-04-24: Since the mere presence of "fp" in the
       register name table overrides this built-in $fp register, there
       is no real reason for this DEPRECATED_FP_REGNUM trickery here.
       An architecture wanting to implement "$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 (DEPRECATED_FP_REGNUM, frame);
  else
    {
      struct value *val = allocate_value (builtin_type_void_data_ptr);
      gdb_byte *buf = value_contents_raw (val);
      if (frame == NULL)
	memset (buf, 0, TYPE_LENGTH (value_type (val)));
      else
	ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
			    get_frame_base_address (frame));
      return val;
    }
}

static struct value *
value_of_builtin_frame_pc_reg (struct frame_info *frame)
{
  if (PC_REGNUM >= 0)
    return value_of_register (PC_REGNUM, frame);
  else
    {
      struct value *val = allocate_value (builtin_type_void_data_ptr);
      gdb_byte *buf = value_contents_raw (val);
      if (frame == NULL)
	memset (buf, 0, TYPE_LENGTH (value_type (val)));
      else
	ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
			    get_frame_pc (frame));
      return val;
    }
}

static struct value *
value_of_builtin_frame_sp_reg (struct frame_info *frame)
{
#ifdef SP_REGNUM
  if (SP_REGNUM >= 0)
    return value_of_register (SP_REGNUM, frame);
#endif
  error (_("Standard register ``$sp'' is not available for this target"));
}

static struct value *
value_of_builtin_frame_ps_reg (struct frame_info *frame)
{
#ifdef PS_REGNUM
  if (PS_REGNUM >= 0)
    return value_of_register (PS_REGNUM, frame);
#endif
  error (_("Standard register ``$ps'' is not available for this target"));
}

extern initialize_file_ftype _initialize_frame_reg; /* -Wmissing-prototypes */

void
_initialize_frame_reg (void)
{
  /* FIXME: cagney/2002-02-08: At present the local builtin types
     can't be initialized using _initialize*() or gdbarch.  Due mainly
     to non-multi-arch targets, GDB initializes things piece meal and,
     as a consequence can leave these types NULL.  */
  DEPRECATED_REGISTER_GDBARCH_SWAP (builtin_type_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);
  user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg);
  user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg);
  user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg);

  /* NOTE: cagney/2002-04-05: For moment leave the $frame / $gdbframe
     / $gdb.frame disabled.  It isn't yet clear which of the many
     options is the best.  */
  if (0)
    user_reg_add_builtin ("frame", value_of_builtin_frame_reg);
}