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/* Code dealing with register stack frames, for GDB, the GNU debugger.

   Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,

   1996, 1997, 1998, 1999, 2000, 2001, 2002, 2007, 2008

   Free Software Foundation, Inc.

   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 "regcache.h"

#include "sentinel-frame.h"

#include "inferior.h"

#include "frame-unwind.h"

struct frame_unwind_cache

{

  struct regcache *regcache;

};

void *

sentinel_frame_cache (struct regcache *regcache)

{

  struct frame_unwind_cache *cache =

    FRAME_OBSTACK_ZALLOC (struct frame_unwind_cache);

  cache->regcache = regcache;

  return cache;

}

/* Here the register value is taken direct from the register cache.  */

static void

sentinel_frame_prev_register (struct frame_info *next_frame,

                              void **this_prologue_cache,

                              int regnum, int *optimized,

                              enum lval_type *lvalp, CORE_ADDR *addrp,

                              int *realnum, gdb_byte *bufferp)

{

  struct frame_unwind_cache *cache = *this_prologue_cache;

  /* Describe the register's location.  A reg-frame maps all registers

     onto the corresponding hardware register.  */

  *optimized = 0;

  *lvalp = lval_register;

  *addrp = 0;

  *realnum = regnum;

  /* If needed, find and return the value of the register.  */

  if (bufferp != NULL)

    {

      /* Return the actual value.  */

      /* Use the regcache_cooked_read() method so that it, on the fly,

         constructs either a raw or pseudo register from the raw

         register cache.  */

      regcache_cooked_read (cache->regcache, regnum, bufferp);

    }

}

static void

sentinel_frame_this_id (struct frame_info *next_frame,

                        void **this_prologue_cache,

                        struct frame_id *this_id)

{

  /* The sentinel frame is used as a starting point for creating the

     previous (inner most) frame.  That frame's THIS_ID method will be

     called to determine the inner most frame's ID.  Not this one.  */

  internal_error (__FILE__, __LINE__, _("sentinel_frame_this_id called"));

}

static CORE_ADDR

sentinel_frame_prev_pc (struct frame_info *next_frame,

                        void **this_prologue_cache)

{

  struct gdbarch *gdbarch = get_frame_arch (next_frame);

  return gdbarch_unwind_pc (gdbarch, next_frame);

}

const struct frame_unwind sentinel_frame_unwinder =

{

  SENTINEL_FRAME,

  sentinel_frame_this_id,

  sentinel_frame_prev_register,

  NULL, /* unwind_data */

  NULL, /* sniffer */

  sentinel_frame_prev_pc,

};

const struct frame_unwind *const sentinel_frame_unwind = &sentinel_frame_unwinder;