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