gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006-2022 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   struct bookmark *next;
  96   int number;
  97   CORE_ADDR pc;
  98   struct symtab_and_line sal;
  99   gdb_byte *opaque_data;
 100 };
 101
 102 static struct bookmark *bookmark_chain;
 103 static int bookmark_count;
 104
 105 #define ALL_BOOKMARKS(B) for ((B) = bookmark_chain; (B); (B) = (B)->next)
 106
 107 #define ALL_BOOKMARKS_SAFE(B,TMP)           \
 108      for ((B) = bookmark_chain;             \
 109           (B) ? ((TMP) = (B)->next, 1) : 0; \
 110           (B) = (TMP))
 111
 112 /* save_bookmark_command -- implement "bookmark" command.
 113    Call target method to get a bookmark identifier.
 114    Insert bookmark identifier into list.
 115
 116    Identifier will be a malloc string (gdb_byte *).
 117    Up to us to free it as required.  */
 118
 119 static void
 120 save_bookmark_command (const char *args, int from_tty)
 121 {
 122   /* Get target's idea of a bookmark.  */
 123   gdb_byte *bookmark_id = target_get_bookmark (args, from_tty);
 124   struct gdbarch *gdbarch = get_current_regcache ()->arch ();
 125
 126   /* CR should not cause another identical bookmark.  */
 127   dont_repeat ();
 128
 129   if (bookmark_id == NULL)
 130     error (_("target_get_bookmark failed."));
 131
 132   /* Set up a bookmark struct.  */
 133   bookmark *b = new bookmark ();
 134   b->number = ++bookmark_count;
 135   b->pc = regcache_read_pc (get_current_regcache ());
 136   b->sal = find_pc_line (b->pc, 0);
 137   b->sal.pspace = get_frame_program_space (get_current_frame ());
 138   b->opaque_data = bookmark_id;
 139   b->next = NULL;
 140
 141   /* Add this bookmark to the end of the chain, so that a list
 142      of bookmarks will come out in order of increasing numbers.  */
 143
 144   bookmark *b1 = bookmark_chain;
 145   if (b1 == 0)
 146     bookmark_chain = b;
 147   else
 148     {
 149       while (b1->next)
 150         b1 = b1->next;
 151       b1->next = b;
 152     }
 153   gdb_printf (_("Saved bookmark %d at %s\n"), b->number,
 154               paddress (gdbarch, b->sal.pc));
 155 }
 156
 157 /* Implement "delete bookmark" command.  */
 158
 159 static int
 160 delete_one_bookmark (int num)
 161 {
 162   struct bookmark *b1, *b;
 163
 164   /* Find bookmark with corresponding number.  */
 165   ALL_BOOKMARKS (b)
 166     if (b->number == num)
 167       break;
 168
 169   /* Special case, first item in list.  */
 170   if (b == bookmark_chain)
 171     bookmark_chain = b->next;
 172
 173   /* Find bookmark preceding "marked" one, so we can unlink.  */
 174   if (b)
 175     {
 176       ALL_BOOKMARKS (b1)
 177         if (b1->next == b)
 178           {
 179             /* Found designated bookmark.  Unlink and delete.  */
 180             b1->next = b->next;
 181             break;
 182           }
 183       xfree (b->opaque_data);
 184       delete b;
 185       return 1;         /* success */
 186     }
 187   return 0;             /* failure */
 188 }
 189
 190 static void
 191 delete_all_bookmarks (void)
 192 {
 193   struct bookmark *b, *b1;
 194
 195   ALL_BOOKMARKS_SAFE (b, b1)
 196     {
 197       xfree (b->opaque_data);
 198       xfree (b);
 199     }
 200   bookmark_chain = NULL;
 201 }
 202
 203 static void
 204 delete_bookmark_command (const char *args, int from_tty)
 205 {
 206   if (bookmark_chain == NULL)
 207     {
 208       warning (_("No bookmarks."));
 209       return;
 210     }
 211
 212   if (args == NULL || args[0] == '\0')
 213     {
 214       if (from_tty && !query (_("Delete all bookmarks? ")))
 215         return;
 216       delete_all_bookmarks ();
 217       return;
 218     }
 219
 220   number_or_range_parser parser (args);
 221   while (!parser.finished ())
 222     {
 223       int num = parser.get_number ();
 224       if (!delete_one_bookmark (num))
 225         /* Not found.  */
 226         warning (_("No bookmark #%d."), num);
 227     }
 228 }
 229
 230 /* Implement "goto-bookmark" command.  */
 231
 232 static void
 233 goto_bookmark_command (const char *args, int from_tty)
 234 {
 235   struct bookmark *b;
 236   unsigned long num;
 237   const char *p = args;
 238
 239   if (args == NULL || args[0] == '\0')
 240     error (_("Command requires an argument."));
 241
 242   if (startswith (args, "start")
 243       || startswith (args, "begin")
 244       || startswith (args, "end"))
 245     {
 246       /* Special case.  Give target opportunity to handle.  */
 247       target_goto_bookmark ((gdb_byte *) args, from_tty);
 248       return;
 249     }
 250
 251   if (args[0] == '\'' || args[0] == '\"')
 252     {
 253       /* Special case -- quoted string.  Pass on to target.  */
 254       if (args[strlen (args) - 1] != args[0])
 255         error (_("Unbalanced quotes: %s"), args);
 256       target_goto_bookmark ((gdb_byte *) args, from_tty);
 257       return;
 258     }
 259
 260   /* General case.  Bookmark identified by bookmark number.  */
 261   num = get_number (&args);
 262
 263   if (num == 0)
 264     error (_("goto-bookmark: invalid bookmark number '%s'."), p);
 265
 266   ALL_BOOKMARKS (b)
 267     if (b->number == num)
 268       break;
 269
 270   if (b)
 271     {
 272       /* Found.  Send to target method.  */
 273       target_goto_bookmark (b->opaque_data, from_tty);
 274       return;
 275     }
 276   /* Not found.  */
 277   error (_("goto-bookmark: no bookmark found for '%s'."), p);
 278 }
 279
 280 static int
 281 bookmark_1 (int bnum)
 282 {
 283   struct gdbarch *gdbarch = get_current_regcache ()->arch ();
 284   struct bookmark *b;
 285   int matched = 0;
 286
 287   ALL_BOOKMARKS (b)
 288   {
 289     if (bnum == -1 || bnum == b->number)
 290       {
 291         gdb_printf ("   %d       %s    '%s'\n",
 292                     b->number,
 293                     paddress (gdbarch, b->pc),
 294                     b->opaque_data);
 295         matched++;
 296       }
 297   }
 298
 299   if (bnum > 0 && matched == 0)
 300     gdb_printf ("No bookmark #%d\n", bnum);
 301
 302   return matched;
 303 }
 304
 305 /* Implement "info bookmarks" command.  */
 306
 307 static void
 308 info_bookmarks_command (const char *args, int from_tty)
 309 {
 310   if (!bookmark_chain)
 311     gdb_printf (_("No bookmarks.\n"));
 312   else if (args == NULL || *args == '\0')
 313     bookmark_1 (-1);
 314   else
 315     {
 316       number_or_range_parser parser (args);
 317       while (!parser.finished ())
 318         {
 319           int bnum = parser.get_number ();
 320           bookmark_1 (bnum);
 321         }
 322     }
 323 }
 324
 325 void _initialize_reverse ();
 326 void
 327 _initialize_reverse ()
 328 {
 329   cmd_list_element *reverse_step_cmd
 330    = add_com ("reverse-step", class_run, reverse_step, _("\
 331 Step program backward until it reaches the beginning of another source line.\n\
 332 Argument N means do this N times (or till program stops for another reason)."));
 333   add_com_alias ("rs", reverse_step_cmd, class_run, 1);
 334
 335   cmd_list_element *reverse_next_cmd
 336     = add_com ("reverse-next", class_run, reverse_next, _("\
 337 Step program backward, proceeding through subroutine calls.\n\
 338 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 339 when they do, the call is treated as one instruction.\n\
 340 Argument N means do this N times (or till program stops for another reason)."));
 341   add_com_alias ("rn", reverse_next_cmd, class_run, 1);
 342
 343   cmd_list_element *reverse_stepi_cmd
 344     = add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 345 Step backward exactly one instruction.\n\
 346 Argument N means do this N times (or till program stops for another reason)."));
 347   add_com_alias ("rsi", reverse_stepi_cmd, class_run, 0);
 348
 349   cmd_list_element *reverse_nexti_cmd
 350     = add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 351 Step backward one instruction, but proceed through called subroutines.\n\
 352 Argument N means do this N times (or till program stops for another reason)."));
 353   add_com_alias ("rni", reverse_nexti_cmd, class_run, 0);
 354
 355   cmd_list_element *reverse_continue_cmd
 356     = add_com ("reverse-continue", class_run, reverse_continue, _("\
 357 Continue program being debugged but run it in reverse.\n\
 358 If proceeding from breakpoint, a number N may be used as an argument,\n\
 359 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 360 the breakpoint won't break until the Nth time it is reached)."));
 361   add_com_alias ("rc", reverse_continue_cmd, class_run, 0);
 362
 363   add_com ("reverse-finish", class_run, reverse_finish, _("\
 364 Execute backward until just before selected stack frame is called."));
 365
 366   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 367 Set a bookmark in the program's execution history.\n\
 368 A bookmark represents a point in the execution history \n\
 369 that can be returned to at a later point in the debug session."));
 370   add_info ("bookmarks", info_bookmarks_command, _("\
 371 Status of user-settable bookmarks.\n\
 372 Bookmarks are user-settable markers representing a point in the \n\
 373 execution history that can be returned to later in the same debug \n\
 374 session."));
 375   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 376 Delete a bookmark from the bookmark list.\n\
 377 Argument is a bookmark number or numbers,\n\
 378  or no argument to delete all bookmarks."),
 379            &deletelist);
 380   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 381 Go to an earlier-bookmarked point in the program's execution history.\n\
 382 Argument is the bookmark number of a bookmark saved earlier by using \n\
 383 the 'bookmark' command, or the special arguments:\n\
 384   start (beginning of recording)\n\
 385   end   (end of recording)"));
 386 }