gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdb_string.h"
  23 #include "target.h"
  24 #include "top.h"
  25 #include "cli/cli-cmds.h"
  26 #include "cli/cli-decode.h"
  27 #include "cli/cli-utils.h"
  28 #include "inferior.h"
  29 #include "regcache.h"
  30
  31 /* User interface:
  32    reverse-step, reverse-next etc.  */
  33
  34 static void
  35 exec_direction_default (void *notused)
  36 {
  37   /* Return execution direction to default state.  */
  38   execution_direction = EXEC_FORWARD;
  39 }
  40
  41 /* exec_reverse_once -- accepts an arbitrary gdb command (string),
  42    and executes it with exec-direction set to 'reverse'.
  43
  44    Used to implement reverse-next etc. commands.  */
  45
  46 static void
  47 exec_reverse_once (char *cmd, char *args, int from_tty)
  48 {
  49   char *reverse_command;
  50   enum exec_direction_kind dir = execution_direction;
  51   struct cleanup *old_chain;
  52
  53   if (dir == EXEC_ERROR)
  54     error (_("Target %s does not support this command."), target_shortname);
  55
  56   if (dir == EXEC_REVERSE)
  57     error (_("Already in reverse mode.  Use '%s' or 'set exec-dir forward'."),
  58            cmd);
  59
  60   if (!target_can_execute_reverse)
  61     error (_("Target %s does not support this command."), target_shortname);
  62
  63   reverse_command = xstrprintf ("%s %s", cmd, args ? args : "");
  64   old_chain = make_cleanup (exec_direction_default, NULL);
  65   make_cleanup (xfree, reverse_command);
  66   execution_direction = EXEC_REVERSE;
  67   execute_command (reverse_command, from_tty);
  68   do_cleanups (old_chain);
  69 }
  70
  71 static void
  72 reverse_step (char *args, int from_tty)
  73 {
  74   exec_reverse_once ("step", args, from_tty);
  75 }
  76
  77 static void
  78 reverse_stepi (char *args, int from_tty)
  79 {
  80   exec_reverse_once ("stepi", args, from_tty);
  81 }
  82
  83 static void
  84 reverse_next (char *args, int from_tty)
  85 {
  86   exec_reverse_once ("next", args, from_tty);
  87 }
  88
  89 static void
  90 reverse_nexti (char *args, int from_tty)
  91 {
  92   exec_reverse_once ("nexti", args, from_tty);
  93 }
  94
  95 static void
  96 reverse_continue (char *args, int from_tty)
  97 {
  98   exec_reverse_once ("continue", args, from_tty);
  99 }
 100
 101 static void
 102 reverse_finish (char *args, int from_tty)
 103 {
 104   exec_reverse_once ("finish", args, from_tty);
 105 }
 106
 107 /* Data structures for a bookmark list.  */
 108
 109 struct bookmark {
 110   struct bookmark *next;
 111   int number;
 112   CORE_ADDR pc;
 113   struct symtab_and_line sal;
 114   gdb_byte *opaque_data;
 115 };
 116
 117 static struct bookmark *bookmark_chain;
 118 static int bookmark_count;
 119
 120 #define ALL_BOOKMARKS(B) for ((B) = bookmark_chain; (B); (B) = (B)->next)
 121
 122 #define ALL_BOOKMARKS_SAFE(B,TMP)           \
 123      for ((B) = bookmark_chain;             \
 124           (B) ? ((TMP) = (B)->next, 1) : 0; \
 125           (B) = (TMP))
 126
 127 /* save_bookmark_command -- implement "bookmark" command.
 128    Call target method to get a bookmark identifier.
 129    Insert bookmark identifier into list.
 130
 131    Identifier will be a malloc string (gdb_byte *).
 132    Up to us to free it as required.  */
 133
 134 static void
 135 save_bookmark_command (char *args, int from_tty)
 136 {
 137   /* Get target's idea of a bookmark.  */
 138   gdb_byte *bookmark_id = target_get_bookmark (args, from_tty);
 139   struct bookmark *b, *b1;
 140   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 141
 142   /* CR should not cause another identical bookmark.  */
 143   dont_repeat ();
 144
 145   if (bookmark_id == NULL)
 146     error (_("target_get_bookmark failed."));
 147
 148   /* Set up a bookmark struct.  */
 149   b = xcalloc (1, sizeof (struct bookmark));
 150   b->number = ++bookmark_count;
 151   init_sal (&b->sal);
 152   b->pc = regcache_read_pc (get_current_regcache ());
 153   b->sal = find_pc_line (b->pc, 0);
 154   b->sal.pspace = get_frame_program_space (get_current_frame ());
 155   b->opaque_data = bookmark_id;
 156   b->next = NULL;
 157
 158   /* Add this bookmark to the end of the chain, so that a list
 159      of bookmarks will come out in order of increasing numbers.  */
 160
 161   b1 = bookmark_chain;
 162   if (b1 == 0)
 163     bookmark_chain = b;
 164   else
 165     {
 166       while (b1->next)
 167         b1 = b1->next;
 168       b1->next = b;
 169     }
 170   printf_filtered (_("Saved bookmark %d at %s\n"), b->number,
 171                      paddress (gdbarch, b->sal.pc));
 172 }
 173
 174 /* Implement "delete bookmark" command.  */
 175
 176 static int
 177 delete_one_bookmark (int num)
 178 {
 179   struct bookmark *b1, *b;
 180
 181   /* Find bookmark with corresponding number.  */
 182   ALL_BOOKMARKS (b)
 183     if (b->number == num)
 184       break;
 185
 186   /* Special case, first item in list.  */
 187   if (b == bookmark_chain)
 188     bookmark_chain = b->next;
 189
 190   /* Find bookmark preceeding "marked" one, so we can unlink.  */
 191   if (b)
 192     {
 193       ALL_BOOKMARKS (b1)
 194         if (b1->next == b)
 195           {
 196             /* Found designated bookmark.  Unlink and delete.  */
 197             b1->next = b->next;
 198             break;
 199           }
 200       xfree (b->opaque_data);
 201       xfree (b);
 202       return 1;         /* success */
 203     }
 204   return 0;             /* failure */
 205 }
 206
 207 static void
 208 delete_all_bookmarks (void)
 209 {
 210   struct bookmark *b, *b1;
 211
 212   ALL_BOOKMARKS_SAFE (b, b1)
 213     {
 214       xfree (b->opaque_data);
 215       xfree (b);
 216     }
 217   bookmark_chain = NULL;
 218 }
 219
 220 static void
 221 delete_bookmark_command (char *args, int from_tty)
 222 {
 223   struct bookmark *b;
 224   int num;
 225   struct get_number_or_range_state state;
 226
 227   if (bookmark_chain == NULL)
 228     {
 229       warning (_("No bookmarks."));
 230       return;
 231     }
 232
 233   if (args == NULL || args[0] == '\0')
 234     {
 235       if (from_tty && !query (_("Delete all bookmarks? ")))
 236         return;
 237       delete_all_bookmarks ();
 238       return;
 239     }
 240
 241   init_number_or_range (&state, args);
 242   while (!state.finished)
 243     {
 244       num = get_number_or_range (&state);
 245       if (!delete_one_bookmark (num))
 246         /* Not found.  */
 247         warning (_("No bookmark #%d."), num);
 248     }
 249 }
 250
 251 /* Implement "goto-bookmark" command.  */
 252
 253 static void
 254 goto_bookmark_command (char *args, int from_tty)
 255 {
 256   struct bookmark *b;
 257   unsigned long num;
 258
 259   if (args == NULL || args[0] == '\0')
 260     error (_("Command requires an argument."));
 261
 262   if (strncmp (args, "start", strlen ("start")) == 0
 263       || strncmp (args, "begin", strlen ("begin")) == 0
 264       || strncmp (args, "end",   strlen ("end")) == 0)
 265     {
 266       /* Special case.  Give target opportunity to handle.  */
 267       target_goto_bookmark (args, from_tty);
 268       return;
 269     }
 270
 271   if (args[0] == '\'' || args[0] == '\"')
 272     {
 273       /* Special case -- quoted string.  Pass on to target.  */
 274       if (args[strlen (args) - 1] != args[0])
 275         error (_("Unbalanced quotes: %s"), args);
 276       target_goto_bookmark (args, from_tty);
 277       return;
 278     }
 279
 280   /* General case.  Bookmark identified by bookmark number.  */
 281   num = get_number (&args);
 282   ALL_BOOKMARKS (b)
 283     if (b->number == num)
 284       break;
 285
 286   if (b)
 287     {
 288       /* Found.  Send to target method.  */
 289       target_goto_bookmark (b->opaque_data, from_tty);
 290       return;
 291     }
 292   /* Not found.  */
 293   error (_("goto-bookmark: no bookmark found for '%s'."), args);
 294 }
 295
 296 static int
 297 bookmark_1 (int bnum)
 298 {
 299   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 300   struct bookmark *b;
 301   int matched = 0;
 302
 303   ALL_BOOKMARKS (b)
 304   {
 305     if (bnum == -1 || bnum == b->number)
 306       {
 307         printf_filtered ("   %d       %s    '%s'\n",
 308                          b->number,
 309                          paddress (gdbarch, b->pc),
 310                          b->opaque_data);
 311         matched++;
 312       }
 313   }
 314
 315   if (bnum > 0 && matched == 0)
 316     printf_filtered ("No bookmark #%d\n", bnum);
 317
 318   return matched;
 319 }
 320
 321 /* Implement "info bookmarks" command.  */
 322
 323 static void
 324 bookmarks_info (char *args, int from_tty)
 325 {
 326   int bnum = -1;
 327
 328   if (!bookmark_chain)
 329     printf_filtered (_("No bookmarks.\n"));
 330   else if (args == NULL || *args == '\0')
 331     bookmark_1 (-1);
 332   else
 333     {
 334       struct get_number_or_range_state state;
 335
 336       init_number_or_range (&state, args);
 337       while (!state.finished)
 338         {
 339           bnum = get_number_or_range (&state);
 340           bookmark_1 (bnum);
 341         }
 342     }
 343 }
 344
 345
 346 /* Provide a prototype to silence -Wmissing-prototypes.  */
 347 extern initialize_file_ftype _initialize_reverse;
 348
 349 void
 350 _initialize_reverse (void)
 351 {
 352   add_com ("reverse-step", class_run, reverse_step, _("\
 353 Step program backward until it reaches the beginning of another source line.\n\
 354 Argument N means do this N times (or till program stops for another reason).")
 355            );
 356   add_com_alias ("rs", "reverse-step", class_alias, 1);
 357
 358   add_com ("reverse-next", class_run, reverse_next, _("\
 359 Step program backward, proceeding through subroutine calls.\n\
 360 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 361 when they do, the call is treated as one instruction.\n\
 362 Argument N means do this N times (or till program stops for another reason).")
 363            );
 364   add_com_alias ("rn", "reverse-next", class_alias, 1);
 365
 366   add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 367 Step backward exactly one instruction.\n\
 368 Argument N means do this N times (or till program stops for another reason).")
 369            );
 370   add_com_alias ("rsi", "reverse-stepi", class_alias, 0);
 371
 372   add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 373 Step backward one instruction, but proceed through called subroutines.\n\
 374 Argument N means do this N times (or till program stops for another reason).")
 375            );
 376   add_com_alias ("rni", "reverse-nexti", class_alias, 0);
 377
 378   add_com ("reverse-continue", class_run, reverse_continue, _("\
 379 Continue program being debugged but run it in reverse.\n\
 380 If proceeding from breakpoint, a number N may be used as an argument,\n\
 381 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 382 the breakpoint won't break until the Nth time it is reached)."));
 383   add_com_alias ("rc", "reverse-continue", class_alias, 0);
 384
 385   add_com ("reverse-finish", class_run, reverse_finish, _("\
 386 Execute backward until just before selected stack frame is called."));
 387
 388   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 389 Set a bookmark in the program's execution history.\n\
 390 A bookmark represents a point in the execution history \n\
 391 that can be returned to at a later point in the debug session."));
 392   add_info ("bookmarks", bookmarks_info, _("\
 393 Status of user-settable bookmarks.\n\
 394 Bookmarks are user-settable markers representing a point in the \n\
 395 execution history that can be returned to later in the same debug \n\
 396 session."));
 397   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 398 Delete a bookmark from the bookmark list.\n\
 399 Argument is a bookmark number or numbers,\n\
 400  or no argument to delete all bookmarks.\n"),
 401            &deletelist);
 402   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 403 Go to an earlier-bookmarked point in the program's execution history.\n\
 404 Argument is the bookmark number of a bookmark saved earlier by using \n\
 405 the 'bookmark' command, or the special arguments:\n\
 406   start (beginning of recording)\n\
 407   end   (end of recording)\n"));
 408 }