gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006-2017 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, 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[0], from_tty);
  54 }
  55
  56 static void
  57 reverse_step (char *args, int from_tty)
  58 {
  59   exec_reverse_once ("step", args, from_tty);
  60 }
  61
  62 static void
  63 reverse_stepi (char *args, int from_tty)
  64 {
  65   exec_reverse_once ("stepi", args, from_tty);
  66 }
  67
  68 static void
  69 reverse_next (char *args, int from_tty)
  70 {
  71   exec_reverse_once ("next", args, from_tty);
  72 }
  73
  74 static void
  75 reverse_nexti (char *args, int from_tty)
  76 {
  77   exec_reverse_once ("nexti", args, from_tty);
  78 }
  79
  80 static void
  81 reverse_continue (char *args, int from_tty)
  82 {
  83   exec_reverse_once ("continue", args, from_tty);
  84 }
  85
  86 static void
  87 reverse_finish (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 (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 bookmark *b, *b1;
 125   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 126
 127   /* CR should not cause another identical bookmark.  */
 128   dont_repeat ();
 129
 130   if (bookmark_id == NULL)
 131     error (_("target_get_bookmark failed."));
 132
 133   /* Set up a bookmark struct.  */
 134   b = XCNEW (struct bookmark);
 135   b->number = ++bookmark_count;
 136   init_sal (&b->sal);
 137   b->pc = regcache_read_pc (get_current_regcache ());
 138   b->sal = find_pc_line (b->pc, 0);
 139   b->sal.pspace = get_frame_program_space (get_current_frame ());
 140   b->opaque_data = bookmark_id;
 141   b->next = NULL;
 142
 143   /* Add this bookmark to the end of the chain, so that a list
 144      of bookmarks will come out in order of increasing numbers.  */
 145
 146   b1 = bookmark_chain;
 147   if (b1 == 0)
 148     bookmark_chain = b;
 149   else
 150     {
 151       while (b1->next)
 152         b1 = b1->next;
 153       b1->next = b;
 154     }
 155   printf_filtered (_("Saved bookmark %d at %s\n"), b->number,
 156                      paddress (gdbarch, b->sal.pc));
 157 }
 158
 159 /* Implement "delete bookmark" command.  */
 160
 161 static int
 162 delete_one_bookmark (int num)
 163 {
 164   struct bookmark *b1, *b;
 165
 166   /* Find bookmark with corresponding number.  */
 167   ALL_BOOKMARKS (b)
 168     if (b->number == num)
 169       break;
 170
 171   /* Special case, first item in list.  */
 172   if (b == bookmark_chain)
 173     bookmark_chain = b->next;
 174
 175   /* Find bookmark preceding "marked" one, so we can unlink.  */
 176   if (b)
 177     {
 178       ALL_BOOKMARKS (b1)
 179         if (b1->next == b)
 180           {
 181             /* Found designated bookmark.  Unlink and delete.  */
 182             b1->next = b->next;
 183             break;
 184           }
 185       xfree (b->opaque_data);
 186       xfree (b);
 187       return 1;         /* success */
 188     }
 189   return 0;             /* failure */
 190 }
 191
 192 static void
 193 delete_all_bookmarks (void)
 194 {
 195   struct bookmark *b, *b1;
 196
 197   ALL_BOOKMARKS_SAFE (b, b1)
 198     {
 199       xfree (b->opaque_data);
 200       xfree (b);
 201     }
 202   bookmark_chain = NULL;
 203 }
 204
 205 static void
 206 delete_bookmark_command (char *args, int from_tty)
 207 {
 208   if (bookmark_chain == NULL)
 209     {
 210       warning (_("No bookmarks."));
 211       return;
 212     }
 213
 214   if (args == NULL || args[0] == '\0')
 215     {
 216       if (from_tty && !query (_("Delete all bookmarks? ")))
 217         return;
 218       delete_all_bookmarks ();
 219       return;
 220     }
 221
 222   number_or_range_parser parser (args);
 223   while (!parser.finished ())
 224     {
 225       int num = parser.get_number ();
 226       if (!delete_one_bookmark (num))
 227         /* Not found.  */
 228         warning (_("No bookmark #%d."), num);
 229     }
 230 }
 231
 232 /* Implement "goto-bookmark" command.  */
 233
 234 static void
 235 goto_bookmark_command (char *args, int from_tty)
 236 {
 237   struct bookmark *b;
 238   unsigned long num;
 239   char *p = args;
 240
 241   if (args == NULL || args[0] == '\0')
 242     error (_("Command requires an argument."));
 243
 244   if (startswith (args, "start")
 245       || startswith (args, "begin")
 246       || startswith (args, "end"))
 247     {
 248       /* Special case.  Give target opportunity to handle.  */
 249       target_goto_bookmark ((gdb_byte *) args, from_tty);
 250       return;
 251     }
 252
 253   if (args[0] == '\'' || args[0] == '\"')
 254     {
 255       /* Special case -- quoted string.  Pass on to target.  */
 256       if (args[strlen (args) - 1] != args[0])
 257         error (_("Unbalanced quotes: %s"), args);
 258       target_goto_bookmark ((gdb_byte *) args, from_tty);
 259       return;
 260     }
 261
 262   /* General case.  Bookmark identified by bookmark number.  */
 263   num = get_number (&args);
 264
 265   if (num == 0)
 266     error (_("goto-bookmark: invalid bookmark number '%s'."), p);
 267
 268   ALL_BOOKMARKS (b)
 269     if (b->number == num)
 270       break;
 271
 272   if (b)
 273     {
 274       /* Found.  Send to target method.  */
 275       target_goto_bookmark (b->opaque_data, from_tty);
 276       return;
 277     }
 278   /* Not found.  */
 279   error (_("goto-bookmark: no bookmark found for '%s'."), p);
 280 }
 281
 282 static int
 283 bookmark_1 (int bnum)
 284 {
 285   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 286   struct bookmark *b;
 287   int matched = 0;
 288
 289   ALL_BOOKMARKS (b)
 290   {
 291     if (bnum == -1 || bnum == b->number)
 292       {
 293         printf_filtered ("   %d       %s    '%s'\n",
 294                          b->number,
 295                          paddress (gdbarch, b->pc),
 296                          b->opaque_data);
 297         matched++;
 298       }
 299   }
 300
 301   if (bnum > 0 && matched == 0)
 302     printf_filtered ("No bookmark #%d\n", bnum);
 303
 304   return matched;
 305 }
 306
 307 /* Implement "info bookmarks" command.  */
 308
 309 static void
 310 info_bookmarks_command (char *args, int from_tty)
 311 {
 312   if (!bookmark_chain)
 313     printf_filtered (_("No bookmarks.\n"));
 314   else if (args == NULL || *args == '\0')
 315     bookmark_1 (-1);
 316   else
 317     {
 318       number_or_range_parser parser (args);
 319       while (!parser.finished ())
 320         {
 321           int bnum = parser.get_number ();
 322           bookmark_1 (bnum);
 323         }
 324     }
 325 }
 326
 327
 328 /* Provide a prototype to silence -Wmissing-prototypes.  */
 329 extern initialize_file_ftype _initialize_reverse;
 330
 331 void
 332 _initialize_reverse (void)
 333 {
 334   add_com ("reverse-step", class_run, reverse_step, _("\
 335 Step program backward until it reaches the beginning of another source line.\n\
 336 Argument N means do this N times (or till program stops for another reason).")
 337            );
 338   add_com_alias ("rs", "reverse-step", class_alias, 1);
 339
 340   add_com ("reverse-next", class_run, reverse_next, _("\
 341 Step program backward, proceeding through subroutine calls.\n\
 342 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 343 when they do, the call is treated as one instruction.\n\
 344 Argument N means do this N times (or till program stops for another reason).")
 345            );
 346   add_com_alias ("rn", "reverse-next", class_alias, 1);
 347
 348   add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 349 Step backward exactly one instruction.\n\
 350 Argument N means do this N times (or till program stops for another reason).")
 351            );
 352   add_com_alias ("rsi", "reverse-stepi", class_alias, 0);
 353
 354   add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 355 Step backward one instruction, but proceed through called subroutines.\n\
 356 Argument N means do this N times (or till program stops for another reason).")
 357            );
 358   add_com_alias ("rni", "reverse-nexti", class_alias, 0);
 359
 360   add_com ("reverse-continue", class_run, reverse_continue, _("\
 361 Continue program being debugged but run it in reverse.\n\
 362 If proceeding from breakpoint, a number N may be used as an argument,\n\
 363 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 364 the breakpoint won't break until the Nth time it is reached)."));
 365   add_com_alias ("rc", "reverse-continue", class_alias, 0);
 366
 367   add_com ("reverse-finish", class_run, reverse_finish, _("\
 368 Execute backward until just before selected stack frame is called."));
 369
 370   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 371 Set a bookmark in the program's execution history.\n\
 372 A bookmark represents a point in the execution history \n\
 373 that can be returned to at a later point in the debug session."));
 374   add_info ("bookmarks", info_bookmarks_command, _("\
 375 Status of user-settable bookmarks.\n\
 376 Bookmarks are user-settable markers representing a point in the \n\
 377 execution history that can be returned to later in the same debug \n\
 378 session."));
 379   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 380 Delete a bookmark from the bookmark list.\n\
 381 Argument is a bookmark number or numbers,\n\
 382  or no argument to delete all bookmarks.\n"),
 383            &deletelist);
 384   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 385 Go to an earlier-bookmarked point in the program's execution history.\n\
 386 Argument is the bookmark number of a bookmark saved earlier by using \n\
 387 the 'bookmark' command, or the special arguments:\n\
 388   start (beginning of recording)\n\
 389   end   (end of recording)\n"));
 390 }