gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006-2023 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 #include "defs.h"
  21 #include "target.h"
  22 #include "top.h"
  23 #include "cli/cli-cmds.h"
  24 #include "cli/cli-decode.h"
  25 #include "cli/cli-utils.h"
  26 #include "inferior.h"
  27 #include "infrun.h"
  28 #include "regcache.h"
  29
  30 /* User interface:
  31    reverse-step, reverse-next etc.  */
  32
  33 /* exec_reverse_once -- accepts an arbitrary gdb command (string),
  34    and executes it with exec-direction set to 'reverse'.
  35
  36    Used to implement reverse-next etc. commands.  */
  37
  38 static void
  39 exec_reverse_once (const char *cmd, const char *args, int from_tty)
  40 {
  41   enum exec_direction_kind dir = execution_direction;
  42
  43   if (dir == EXEC_REVERSE)
  44     error (_("Already in reverse mode.  Use '%s' or 'set exec-dir forward'."),
  45            cmd);
  46
  47   if (!target_can_execute_reverse ())
  48     error (_("Target %s does not support this command."), target_shortname ());
  49
  50   std::string reverse_command = string_printf ("%s %s", cmd, args ? args : "");
  51   scoped_restore restore_exec_dir
  52     = make_scoped_restore (&execution_direction, EXEC_REVERSE);
  53   execute_command (reverse_command.c_str (), from_tty);
  54 }
  55
  56 static void
  57 reverse_step (const char *args, int from_tty)
  58 {
  59   exec_reverse_once ("step", args, from_tty);
  60 }
  61
  62 static void
  63 reverse_stepi (const char *args, int from_tty)
  64 {
  65   exec_reverse_once ("stepi", args, from_tty);
  66 }
  67
  68 static void
  69 reverse_next (const char *args, int from_tty)
  70 {
  71   exec_reverse_once ("next", args, from_tty);
  72 }
  73
  74 static void
  75 reverse_nexti (const char *args, int from_tty)
  76 {
  77   exec_reverse_once ("nexti", args, from_tty);
  78 }
  79
  80 static void
  81 reverse_continue (const char *args, int from_tty)
  82 {
  83   exec_reverse_once ("continue", args, from_tty);
  84 }
  85
  86 static void
  87 reverse_finish (const char *args, int from_tty)
  88 {
  89   exec_reverse_once ("finish", args, from_tty);
  90 }
  91
  92 /* Data structures for a bookmark list.  */
  93
  94 struct bookmark {
  95   int number = 0;
  96   CORE_ADDR pc = 0;
  97   struct symtab_and_line sal;
  98   gdb::unique_xmalloc_ptr<gdb_byte> opaque_data;
  99 };
 100
 101 static std::vector<struct bookmark> all_bookmarks;
 102 static int bookmark_count;
 103
 104 /* save_bookmark_command -- implement "bookmark" command.
 105    Call target method to get a bookmark identifier.
 106    Insert bookmark identifier into list.
 107
 108    Identifier will be a malloc string (gdb_byte *).
 109    Up to us to free it as required.  */
 110
 111 static void
 112 save_bookmark_command (const char *args, int from_tty)
 113 {
 114   /* Get target's idea of a bookmark.  */
 115   gdb_byte *bookmark_id = target_get_bookmark (args, from_tty);
 116   regcache *regcache = get_thread_regcache (inferior_thread ());
 117   gdbarch *gdbarch = regcache->arch ();
 118
 119   /* CR should not cause another identical bookmark.  */
 120   dont_repeat ();
 121
 122   if (bookmark_id == NULL)
 123     error (_("target_get_bookmark failed."));
 124
 125   /* Set up a bookmark struct.  */
 126   all_bookmarks.emplace_back ();
 127   bookmark &b = all_bookmarks.back ();
 128   b.number = ++bookmark_count;
 129   b.pc = regcache_read_pc (regcache);
 130   b.sal = find_pc_line (b.pc, 0);
 131   b.sal.pspace = get_frame_program_space (get_current_frame ());
 132   b.opaque_data.reset (bookmark_id);
 133
 134   gdb_printf (_("Saved bookmark %d at %s\n"), b.number,
 135               paddress (gdbarch, b.sal.pc));
 136 }
 137
 138 /* Implement "delete bookmark" command.  */
 139
 140 static bool
 141 delete_one_bookmark (int num)
 142 {
 143   /* Find bookmark with corresponding number.  */
 144   for (auto iter = all_bookmarks.begin ();
 145        iter != all_bookmarks.end ();
 146        ++iter)
 147     {
 148       if (iter->number == num)
 149         {
 150           all_bookmarks.erase (iter);
 151           return true;
 152         }
 153     }
 154   return false;
 155 }
 156
 157 static void
 158 delete_all_bookmarks ()
 159 {
 160   all_bookmarks.clear ();
 161 }
 162
 163 static void
 164 delete_bookmark_command (const char *args, int from_tty)
 165 {
 166   if (all_bookmarks.empty ())
 167     {
 168       warning (_("No bookmarks."));
 169       return;
 170     }
 171
 172   if (args == NULL || args[0] == '\0')
 173     {
 174       if (from_tty && !query (_("Delete all bookmarks? ")))
 175         return;
 176       delete_all_bookmarks ();
 177       return;
 178     }
 179
 180   number_or_range_parser parser (args);
 181   while (!parser.finished ())
 182     {
 183       int num = parser.get_number ();
 184       if (!delete_one_bookmark (num))
 185         /* Not found.  */
 186         warning (_("No bookmark #%d."), num);
 187     }
 188 }
 189
 190 /* Implement "goto-bookmark" command.  */
 191
 192 static void
 193 goto_bookmark_command (const char *args, int from_tty)
 194 {
 195   unsigned long num;
 196   const char *p = args;
 197
 198   if (args == NULL || args[0] == '\0')
 199     error (_("Command requires an argument."));
 200
 201   if (startswith (args, "start")
 202       || startswith (args, "begin")
 203       || startswith (args, "end"))
 204     {
 205       /* Special case.  Give target opportunity to handle.  */
 206       target_goto_bookmark ((gdb_byte *) args, from_tty);
 207       return;
 208     }
 209
 210   if (args[0] == '\'' || args[0] == '\"')
 211     {
 212       /* Special case -- quoted string.  Pass on to target.  */
 213       if (args[strlen (args) - 1] != args[0])
 214         error (_("Unbalanced quotes: %s"), args);
 215       target_goto_bookmark ((gdb_byte *) args, from_tty);
 216       return;
 217     }
 218
 219   /* General case.  Bookmark identified by bookmark number.  */
 220   num = get_number (&args);
 221
 222   if (num == 0)
 223     error (_("goto-bookmark: invalid bookmark number '%s'."), p);
 224
 225   for (const bookmark &iter : all_bookmarks)
 226     {
 227       if (iter.number == num)
 228         {
 229           /* Found.  Send to target method.  */
 230           target_goto_bookmark (iter.opaque_data.get (), from_tty);
 231           return;
 232         }
 233     }
 234   /* Not found.  */
 235   error (_("goto-bookmark: no bookmark found for '%s'."), p);
 236 }
 237
 238 static int
 239 bookmark_1 (int bnum)
 240 {
 241   gdbarch *gdbarch = get_thread_regcache (inferior_thread ())->arch ();
 242   int matched = 0;
 243
 244   for (const bookmark &iter : all_bookmarks)
 245     {
 246       if (bnum == -1 || bnum == iter.number)
 247         {
 248           gdb_printf ("   %d       %s    '%s'\n",
 249                       iter.number,
 250                       paddress (gdbarch, iter.pc),
 251                       iter.opaque_data.get ());
 252           matched++;
 253         }
 254     }
 255
 256   if (bnum > 0 && matched == 0)
 257     gdb_printf ("No bookmark #%d\n", bnum);
 258
 259   return matched;
 260 }
 261
 262 /* Implement "info bookmarks" command.  */
 263
 264 static void
 265 info_bookmarks_command (const char *args, int from_tty)
 266 {
 267   if (all_bookmarks.empty ())
 268     gdb_printf (_("No bookmarks.\n"));
 269   else if (args == NULL || *args == '\0')
 270     bookmark_1 (-1);
 271   else
 272     {
 273       number_or_range_parser parser (args);
 274       while (!parser.finished ())
 275         {
 276           int bnum = parser.get_number ();
 277           bookmark_1 (bnum);
 278         }
 279     }
 280 }
 281
 282 void _initialize_reverse ();
 283 void
 284 _initialize_reverse ()
 285 {
 286   cmd_list_element *reverse_step_cmd
 287    = add_com ("reverse-step", class_run, reverse_step, _("\
 288 Step program backward until it reaches the beginning of another source line.\n\
 289 Argument N means do this N times (or till program stops for another reason)."));
 290   add_com_alias ("rs", reverse_step_cmd, class_run, 1);
 291
 292   cmd_list_element *reverse_next_cmd
 293     = add_com ("reverse-next", class_run, reverse_next, _("\
 294 Step program backward, proceeding through subroutine calls.\n\
 295 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 296 when they do, the call is treated as one instruction.\n\
 297 Argument N means do this N times (or till program stops for another reason)."));
 298   add_com_alias ("rn", reverse_next_cmd, class_run, 1);
 299
 300   cmd_list_element *reverse_stepi_cmd
 301     = add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 302 Step backward exactly one instruction.\n\
 303 Argument N means do this N times (or till program stops for another reason)."));
 304   add_com_alias ("rsi", reverse_stepi_cmd, class_run, 0);
 305
 306   cmd_list_element *reverse_nexti_cmd
 307     = add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 308 Step backward one instruction, but proceed through called subroutines.\n\
 309 Argument N means do this N times (or till program stops for another reason)."));
 310   add_com_alias ("rni", reverse_nexti_cmd, class_run, 0);
 311
 312   cmd_list_element *reverse_continue_cmd
 313     = add_com ("reverse-continue", class_run, reverse_continue, _("\
 314 Continue program being debugged but run it in reverse.\n\
 315 If proceeding from breakpoint, a number N may be used as an argument,\n\
 316 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 317 the breakpoint won't break until the Nth time it is reached)."));
 318   add_com_alias ("rc", reverse_continue_cmd, class_run, 0);
 319
 320   add_com ("reverse-finish", class_run, reverse_finish, _("\
 321 Execute backward until just before selected stack frame is called."));
 322
 323   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 324 Set a bookmark in the program's execution history.\n\
 325 A bookmark represents a point in the execution history \n\
 326 that can be returned to at a later point in the debug session."));
 327   add_info ("bookmarks", info_bookmarks_command, _("\
 328 Status of user-settable bookmarks.\n\
 329 Bookmarks are user-settable markers representing a point in the \n\
 330 execution history that can be returned to later in the same debug \n\
 331 session."));
 332   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 333 Delete a bookmark from the bookmark list.\n\
 334 Argument is a bookmark number or numbers,\n\
 335  or no argument to delete all bookmarks."),
 336            &deletelist);
 337   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 338 Go to an earlier-bookmarked point in the program's execution history.\n\
 339 Argument is the bookmark number of a bookmark saved earlier by using \n\
 340 the 'bookmark' command, or the special arguments:\n\
 341   start (beginning of recording)\n\
 342   end   (end of recording)"));
 343 }