gdb/sentinel-frame.c

   1 /* Code dealing with register stack frames, for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #include "regcache.h"
  22 #include "sentinel-frame.h"
  23 #include "inferior.h"
  24 #include "frame-unwind.h"
  25
  26 struct frame_unwind_cache
  27 {
  28   struct regcache *regcache;
  29 };
  30
  31 void *
  32 sentinel_frame_cache (struct regcache *regcache)
  33 {
  34   struct frame_unwind_cache *cache =
  35     FRAME_OBSTACK_ZALLOC (struct frame_unwind_cache);
  36
  37   cache->regcache = regcache;
  38   return cache;
  39 }
  40
  41 /* Here the register value is taken direct from the register cache.  */
  42
  43 static struct value *
  44 sentinel_frame_prev_register (const frame_info_ptr &this_frame,
  45                               void **this_prologue_cache,
  46                               int regnum)
  47 {
  48   struct frame_unwind_cache *cache
  49     = (struct frame_unwind_cache *) *this_prologue_cache;
  50   struct value *value;
  51
  52   frame_id this_frame_id = get_frame_id (this_frame);
  53   gdb_assert (is_sentinel_frame_id (this_frame_id));
  54
  55   value = cache->regcache->cooked_read_value (regnum);
  56
  57   return value;
  58 }
  59
  60 static void
  61 sentinel_frame_this_id (const frame_info_ptr &this_frame,
  62                         void **this_prologue_cache,
  63                         struct frame_id *this_id)
  64 {
  65   /* The sentinel frame is used as a starting point for creating the
  66      previous (inner most) frame.  That frame's THIS_ID method will be
  67      called to determine the inner most frame's ID.  Not this one.  */
  68   internal_error (_("sentinel_frame_this_id called"));
  69 }
  70
  71 static struct gdbarch *
  72 sentinel_frame_prev_arch (const frame_info_ptr &this_frame,
  73                           void **this_prologue_cache)
  74 {
  75   struct frame_unwind_cache *cache
  76     = (struct frame_unwind_cache *) *this_prologue_cache;
  77
  78   return cache->regcache->arch ();
  79 }
  80
  81 const struct frame_unwind sentinel_frame_unwind =
  82 {
  83   "sentinel",
  84   SENTINEL_FRAME,
  85   default_frame_unwind_stop_reason,
  86   sentinel_frame_this_id,
  87   sentinel_frame_prev_register,
  88   NULL,
  89   NULL,
  90   NULL,
  91   sentinel_frame_prev_arch,
  92 };