gdb/continuations.c - gdb

Data types defined

Functions defined

Source code

  1. /* Continuations for GDB, the GNU debugger.

  3.    Copyright (C) 1986-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  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.

  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.

  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/>.  */

  20. #include "defs.h"
  21. #include "gdbthread.h"
  22. #include "inferior.h"
  23. #include "continuations.h"

  25. ‌struct continuation
  26. {
  27.   struct continuation *next;
  28.   continuation_ftype *function;
  29.   continuation_free_arg_ftype *free_arg;
  30.   void *arg;
  31. };

  33. /* Add a new continuation to the continuation chain.  Args are
  34.    FUNCTION to run the continuation up with, and ARG to pass to
  35.    it.  */

  37. static void
  38. ‌make_continuation (struct continuation **pmy_chain,
  39.                    continuation_ftype *function,
  40.                    void *arg,  void (*free_arg) (void *))
  41. {
  42.   struct continuation *new = XNEW (struct continuation);

  44.   new->next = *pmy_chain;
  45.   new->function = function;
  46.   new->free_arg = free_arg;
  47.   new->arg = arg;
  48.   *pmy_chain = new;
  49. }

  51. static void
  52. ‌do_my_continuations_1 (struct continuation **pmy_chain, int err)
  53. {
  54.   struct continuation *ptr;

  56.   while ((ptr = *pmy_chain) != NULL)
  57.     {
  58.       *pmy_chain = ptr->next;        /* Do this first in case of recursion.  */
  59.       (*ptr->function) (ptr->arg, err);
  60.       if (ptr->free_arg)
  61.         (*ptr->free_arg) (ptr->arg);
  62.       xfree (ptr);
  63.     }
  64. }

  66. static void
  67. ‌do_my_continuations (struct continuation **list, int err)
  68. {
  69.   struct continuation *continuations;

  71.   if (*list == NULL)
  72.     return;

  74.   /* Copy the list header into another pointer, and set the global
  75.      list header to null, so that the global list can change as a side
  76.      effect of invoking the continuations and the processing of the
  77.      preexisting continuations will not be affected.  */

  79.   continuations = *list;
  80.   *list = NULL;

  82.   /* Work now on the list we have set aside.  */
  83.   do_my_continuations_1 (&continuations, err);
  84. }

  86. static void
  87. ‌discard_my_continuations_1 (struct continuation **pmy_chain)
  88. {
  89.   struct continuation *ptr;

  91.   while ((ptr = *pmy_chain) != NULL)
  92.     {
  93.       *pmy_chain = ptr->next;
  94.       if (ptr->free_arg)
  95.         (*ptr->free_arg) (ptr->arg);
  96.       xfree (ptr);
  97.     }
  98. }

  100. static void
  101. ‌discard_my_continuations (struct continuation **list)
  102. {
  103.   discard_my_continuations_1 (list);
  104.   *list = NULL;
  105. }

  107. /* Add a continuation to the continuation list of INFERIOR.  The new
  108.    continuation will be added at the front.  */

  110. void
  111. ‌add_inferior_continuation (continuation_ftype *hook, void *args,
  112.                            continuation_free_arg_ftype *free_arg)
  113. {
  114.   struct inferior *inf = current_inferior ();

  116.   make_continuation (&inf->continuations, hook, args, free_arg);
  117. }

  119. /* Do all continuations of the current inferior.  */

  121. void
  122. ‌do_all_inferior_continuations (int err)
  123. {
  124.   struct inferior *inf = current_inferior ();
  125.   do_my_continuations (&inf->continuations, err);
  126. }

  128. /* Get rid of all the inferior-wide continuations of INF.  */

  130. void
  131. ‌discard_all_inferior_continuations (struct inferior *inf)
  132. {
  133.   discard_my_continuations (&inf->continuations);
  134. }

  136. /* Add a continuation to the continuation list of THREAD.  The new
  137.    continuation will be added at the front.  */

  139. void
  140. ‌add_continuation (struct thread_info *thread,
  141.                   continuation_ftype *hook, void *args,
  142.                   continuation_free_arg_ftype *free_arg)
  143. {
  144.   make_continuation (&thread->continuations, hook, args, free_arg);
  145. }

  147. static void
  148. ‌restore_thread_cleanup (void *arg)
  149. {
  150.   ptid_t *ptid_p = arg;

  152.   switch_to_thread (*ptid_p);
  153. }

  155. /* Walk down the continuation list of PTID, and execute all the
  156.    continuations.  There is a problem though.  In some cases new
  157.    continuations may be added while we are in the middle of this loop.
  158.    If this happens they will be added in the front, and done before we
  159.    have a chance of exhausting those that were already there.  We need
  160.    to then save the beginning of the list in a pointer and do the
  161.    continuations from there on, instead of using the global beginning
  162.    of list as our iteration pointer.  */

  164. static void
  165. ‌do_all_continuations_ptid (ptid_t ptid,
  166.                            struct continuation **continuations_p,
  167.                            int err)
  168. {
  169.   struct cleanup *old_chain;
  170.   ptid_t current_thread;

  172.   if (*continuations_p == NULL)
  173.     return;

  175.   current_thread = inferior_ptid;

  177.   /* Restore selected thread on exit.  Don't try to restore the frame
  178.      as well, because:

  180.      - When running continuations, the selected frame is always #0.

  182.      - The continuations may trigger symbol file loads, which may
  183.      change the frame layout (frame ids change), which would trigger
  184.      a warning if we used make_cleanup_restore_current_thread.  */

  186.   old_chain = make_cleanup (restore_thread_cleanup, &current_thread);

  188.   /* Let the continuation see this thread as selected.  */
  189.   switch_to_thread (ptid);

  191.   do_my_continuations (continuations_p, err);

  193.   do_cleanups (old_chain);
  194. }

  196. /* Callback for iterate over threads.  */

  198. static int
  199. ‌do_all_continuations_thread_callback (struct thread_info *thread, void *data)
  200. {
  201.   int err = * (int *) data;
  202.   do_all_continuations_ptid (thread->ptid, &thread->continuations, err);
  203.   return 0;
  204. }

  206. /* Do all continuations of thread THREAD.  */

  208. void
  209. ‌do_all_continuations_thread (struct thread_info *thread, int err)
  210. {
  211.   do_all_continuations_thread_callback (thread, &err);
  212. }

  214. /* Do all continuations of all threads.  */

  216. void
  217. ‌do_all_continuations (int err)
  218. {
  219.   iterate_over_threads (do_all_continuations_thread_callback, &err);
  220. }

  222. /* Callback for iterate over threads.  */

  224. static int
  225. ‌discard_all_continuations_thread_callback (struct thread_info *thread,
  226.                                            void *data)
  227. {
  228.   discard_my_continuations (&thread->continuations);
  229.   return 0;
  230. }

  232. /* Get rid of all the continuations of THREAD.  */

  234. void
  235. ‌discard_all_continuations_thread (struct thread_info *thread)
  236. {
  237.   discard_all_continuations_thread_callback (thread, NULL);
  238. }

  240. /* Get rid of all the continuations of all threads.  */

  242. void
  243. ‌discard_all_continuations (void)
  244. {
  245.   iterate_over_threads (discard_all_continuations_thread_callback, NULL);
  246. }


  249. /* Add a continuation to the intermediate continuation list of THREAD.
  250.    The new continuation will be added at the front.  */

  252. void
  253. ‌add_intermediate_continuation (struct thread_info *thread,
  254.                                continuation_ftype *hook,
  255.                                void *args,
  256.                                continuation_free_arg_ftype *free_arg)
  257. {
  258.   make_continuation (&thread->intermediate_continuations, hook,
  259.                      args, free_arg);
  260. }

  262. /* Walk down the cmd_continuation list, and execute all the
  263.    continuations.  There is a problem though.  In some cases new
  264.    continuations may be added while we are in the middle of this
  265.    loop.  If this happens they will be added in the front, and done
  266.    before we have a chance of exhausting those that were already
  267.    there.  We need to then save the beginning of the list in a pointer
  268.    and do the continuations from there on, instead of using the
  269.    global beginning of list as our iteration pointer.  */

  271. static int
  272. ‌do_all_intermediate_continuations_thread_callback (struct thread_info *thread,
  273.                                                    void *data)
  274. {
  275.   int err = * (int *) data;

  277.   do_all_continuations_ptid (thread->ptid,
  278.                              &thread->intermediate_continuations, err);
  279.   return 0;
  280. }

  282. /* Do all intermediate continuations of thread THREAD.  */

  284. void
  285. ‌do_all_intermediate_continuations_thread (struct thread_info *thread, int err)
  286. {
  287.   do_all_intermediate_continuations_thread_callback (thread, &err);
  288. }

  290. /* Do all intermediate continuations of all threads.  */

  292. void
  293. ‌do_all_intermediate_continuations (int err)
  294. {
  295.   iterate_over_threads (do_all_intermediate_continuations_thread_callback,
  296.                         &err);
  297. }

  299. /* Callback for iterate over threads.  */

  301. static int
  302. ‌discard_all_intermediate_continuations_thread_callback (struct thread_info *thread,
  303.                                                         void *data)
  304. {
  305.   discard_my_continuations (&thread->intermediate_continuations);
  306.   return 0;
  307. }

  309. /* Get rid of all the intermediate continuations of THREAD.  */

  311. void
  312. ‌discard_all_intermediate_continuations_thread (struct thread_info *thread)
  313. {
  314.   discard_all_intermediate_continuations_thread_callback (thread, NULL);
  315. }

  317. /* Get rid of all the intermediate continuations of all threads.  */

  319. void
  320. ‌discard_all_intermediate_continuations (void)
  321. {
  322.   iterate_over_threads (discard_all_intermediate_continuations_thread_callback,
  323.                         NULL);
  324. }