gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006-2025 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 "target.h"
  21 #include "top.h"
  22 #include "cli/cli-cmds.h"
  23 #include "cli/cli-decode.h"
  24 #include "cli/cli-utils.h"
  25 #include "inferior.h"
  26 #include "infrun.h"
  27 #include "regcache.h"
  28
  29 /* User interface:
  30    reverse-step, reverse-next etc.  */
  31
  32 /* exec_reverse_once -- accepts an arbitrary gdb command (string),
  33    and executes it with exec-direction set to 'reverse'.
  34
  35    Used to implement reverse-next etc. commands.  */
  36
  37 static void
  38 exec_reverse_once (const char *cmd, const char *args, int from_tty)
  39 {
  40   enum exec_direction_kind dir = execution_direction;
  41
  42   if (dir == EXEC_REVERSE)
  43     error (_("Already in reverse mode.  Use '%s' or 'set exec-dir forward'."),
  44            cmd);
  45
  46   if (!target_can_execute_reverse ())
  47     error (_("Target %s does not support this command."), target_shortname ());
  48
  49   std::string reverse_command = string_printf ("%s %s", cmd, args ? args : "");
  50   scoped_restore restore_exec_dir
  51     = make_scoped_restore (&execution_direction, EXEC_REVERSE);
  52   execute_command (reverse_command.c_str (), from_tty);
  53 }
  54
  55 static void
  56 reverse_step (const char *args, int from_tty)
  57 {
  58   exec_reverse_once ("step", args, from_tty);
  59 }
  60
  61 static void
  62 reverse_stepi (const char *args, int from_tty)
  63 {
  64   exec_reverse_once ("stepi", args, from_tty);
  65 }
  66
  67 static void
  68 reverse_next (const char *args, int from_tty)
  69 {
  70   exec_reverse_once ("next", args, from_tty);
  71 }
  72
  73 static void
  74 reverse_nexti (const char *args, int from_tty)
  75 {
  76   exec_reverse_once ("nexti", args, from_tty);
  77 }
  78
  79 static void
  80 reverse_continue (const char *args, int from_tty)
  81 {
  82   exec_reverse_once ("continue", args, from_tty);
  83 }
  84
  85 static void
  86 reverse_finish (const char *args, int from_tty)
  87 {
  88   exec_reverse_once ("finish", args, from_tty);
  89 }
  90
  91 /* Data structures for a bookmark list.  */
  92
  93 struct bookmark {
  94   int number = 0;
  95   CORE_ADDR pc = 0;
  96   struct symtab_and_line sal;
  97   gdb::unique_xmalloc_ptr<gdb_byte> opaque_data;
  98 };
  99
 100 static std::vector<struct bookmark> all_bookmarks;
 101 static int bookmark_count;
 102
 103 /* save_bookmark_command -- implement "bookmark" command.
 104    Call target method to get a bookmark identifier.
 105    Insert bookmark identifier into list.
 106
 107    Identifier will be a malloc string (gdb_byte *).
 108    Up to us to free it as required.  */
 109
 110 static void
 111 save_bookmark_command (const char *args, int from_tty)
 112 {
 113   /* Get target's idea of a bookmark.  */
 114   gdb_byte *bookmark_id = target_get_bookmark (args, from_tty);
 115   regcache *regcache = get_thread_regcache (inferior_thread ());
 116   gdbarch *gdbarch = regcache->arch ();
 117
 118   /* CR should not cause another identical bookmark.  */
 119   dont_repeat ();
 120
 121   if (bookmark_id == NULL)
 122     error (_("target_get_bookmark failed."));
 123
 124   /* Set up a bookmark struct.  */
 125   bookmark &b = all_bookmarks.emplace_back ();
 126   b.number = ++bookmark_count;
 127   b.pc = regcache_read_pc (regcache);
 128   b.sal = find_pc_line (b.pc, 0);
 129   b.sal.pspace = get_frame_program_space (get_current_frame ());
 130   b.opaque_data.reset (bookmark_id);
 131
 132   gdb_printf (_("Saved bookmark %d at %s\n"), b.number,
 133               paddress (gdbarch, b.sal.pc));
 134 }
 135
 136 /* Implement "delete bookmark" command.  */
 137
 138 static bool
 139 delete_one_bookmark (int num)
 140 {
 141   /* Find bookmark with corresponding number.  */
 142   for (auto iter = all_bookmarks.begin ();
 143        iter != all_bookmarks.end ();
 144        ++iter)
 145     {
 146       if (iter->number == num)
 147         {
 148           all_bookmarks.erase (iter);
 149           return true;
 150         }
 151     }
 152   return false;
 153 }
 154
 155 static void
 156 delete_all_bookmarks ()
 157 {
 158   all_bookmarks.clear ();
 159 }
 160
 161 static void
 162 delete_bookmark_command (const char *args, int from_tty)
 163 {
 164   if (all_bookmarks.empty ())
 165     {
 166       warning (_("No bookmarks."));
 167       return;
 168     }
 169
 170   if (args == NULL || args[0] == '\0')
 171     {
 172       if (from_tty && !query (_("Delete all bookmarks? ")))
 173         return;
 174       delete_all_bookmarks ();
 175       return;
 176     }
 177
 178   number_or_range_parser parser (args);
 179   while (!parser.finished ())
 180     {
 181       int num = parser.get_number ();
 182       if (!delete_one_bookmark (num))
 183         /* Not found.  */
 184         warning (_("No bookmark #%d."), num);
 185     }
 186 }
 187
 188 /* Implement "goto-bookmark" command.  */
 189
 190 static void
 191 goto_bookmark_command (const char *args, int from_tty)
 192 {
 193   unsigned long num;
 194   const char *p = args;
 195
 196   if (args == NULL || args[0] == '\0')
 197     error (_("Command requires an argument."));
 198
 199   if (startswith (args, "start")
 200       || startswith (args, "begin")
 201       || startswith (args, "end"))
 202     {
 203       /* Special case.  Give target opportunity to handle.  */
 204       target_goto_bookmark ((gdb_byte *) args, from_tty);
 205       return;
 206     }
 207
 208   if (args[0] == '\'' || args[0] == '\"')
 209     {
 210       /* Special case -- quoted string.  Pass on to target.  */
 211       if (args[strlen (args) - 1] != args[0])
 212         error (_("Unbalanced quotes: %s"), args);
 213       target_goto_bookmark ((gdb_byte *) args, from_tty);
 214       return;
 215     }
 216
 217   /* General case.  Bookmark identified by bookmark number.  */
 218   num = get_number (&args);
 219
 220   if (num == 0)
 221     error (_("goto-bookmark: invalid bookmark number '%s'."), p);
 222
 223   for (const bookmark &iter : all_bookmarks)
 224     {
 225       if (iter.number == num)
 226         {
 227           /* Found.  Send to target method.  */
 228           target_goto_bookmark (iter.opaque_data.get (), from_tty);
 229           return;
 230         }
 231     }
 232   /* Not found.  */
 233   error (_("goto-bookmark: no bookmark found for '%s'."), p);
 234 }
 235
 236 static int
 237 bookmark_1 (int bnum)
 238 {
 239   gdbarch *gdbarch = get_thread_regcache (inferior_thread ())->arch ();
 240   int matched = 0;
 241
 242   for (const bookmark &iter : all_bookmarks)
 243     {
 244       if (bnum == -1 || bnum == iter.number)
 245         {
 246           gdb_printf ("   %d       %s    '%s'\n",
 247                       iter.number,
 248                       paddress (gdbarch, iter.pc),
 249                       iter.opaque_data.get ());
 250           matched++;
 251         }
 252     }
 253
 254   if (bnum > 0 && matched == 0)
 255     gdb_printf ("No bookmark #%d\n", bnum);
 256
 257   return matched;
 258 }
 259
 260 /* Implement "info bookmarks" command.  */
 261
 262 static void
 263 info_bookmarks_command (const char *args, int from_tty)
 264 {
 265   if (all_bookmarks.empty ())
 266     gdb_printf (_("No bookmarks.\n"));
 267   else if (args == NULL || *args == '\0')
 268     bookmark_1 (-1);
 269   else
 270     {
 271       number_or_range_parser parser (args);
 272       while (!parser.finished ())
 273         {
 274           int bnum = parser.get_number ();
 275           bookmark_1 (bnum);
 276         }
 277     }
 278 }
 279
 280 INIT_GDB_FILE (reverse)
 281 {
 282   cmd_list_element *reverse_step_cmd
 283    = add_com ("reverse-step", class_run, reverse_step, _("\
 284 Step program backward until it reaches the beginning of another source line.\n\
 285 Argument N means do this N times (or till program stops for another reason)."));
 286   add_com_alias ("rs", reverse_step_cmd, class_run, 1);
 287
 288   cmd_list_element *reverse_next_cmd
 289     = add_com ("reverse-next", class_run, reverse_next, _("\
 290 Step program backward, proceeding through subroutine calls.\n\
 291 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 292 when they do, the call is treated as one instruction.\n\
 293 Argument N means do this N times (or till program stops for another reason)."));
 294   add_com_alias ("rn", reverse_next_cmd, class_run, 1);
 295
 296   cmd_list_element *reverse_stepi_cmd
 297     = add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 298 Step backward exactly one instruction.\n\
 299 Argument N means do this N times (or till program stops for another reason)."));
 300   add_com_alias ("rsi", reverse_stepi_cmd, class_run, 0);
 301
 302   cmd_list_element *reverse_nexti_cmd
 303     = add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 304 Step backward one instruction, but proceed through called subroutines.\n\
 305 Argument N means do this N times (or till program stops for another reason)."));
 306   add_com_alias ("rni", reverse_nexti_cmd, class_run, 0);
 307
 308   cmd_list_element *reverse_continue_cmd
 309     = add_com ("reverse-continue", class_run, reverse_continue, _("\
 310 Continue program being debugged but run it in reverse.\n\
 311 If proceeding from breakpoint, a number N may be used as an argument,\n\
 312 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 313 the breakpoint won't break until the Nth time it is reached)."));
 314   add_com_alias ("rc", reverse_continue_cmd, class_run, 0);
 315
 316   add_com ("reverse-finish", class_run, reverse_finish, _("\
 317 Execute backward until just before selected stack frame is called."));
 318
 319   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 320 Set a bookmark in the program's execution history.\n\
 321 A bookmark represents a point in the execution history\n\
 322 that can be returned to at a later point in the debug session."));
 323   add_info ("bookmarks", info_bookmarks_command, _("\
 324 Status of user-settable bookmarks.\n\
 325 Bookmarks are user-settable markers representing a point in the\n\
 326 execution history that can be returned to later in the same debug\n\
 327 session."));
 328   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 329 Delete a bookmark from the bookmark list.\n\
 330 Argument is a bookmark number or numbers,\n\
 331  or no argument to delete all bookmarks."),
 332            &deletelist);
 333   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 334 Go to an earlier-bookmarked point in the program's execution history.\n\
 335 Argument is the bookmark number of a bookmark saved earlier by using\n\
 336 the 'bookmark' command, or the special arguments:\n\
 337   start (beginning of recording)\n\
 338   end   (end of recording)"));
 339 }