gdb/reverse.c

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