1 /* Multi-process/thread control defs for GDB, the GNU debugger.
2 Copyright (C) 1987-2015 Free Software Foundation, Inc.
3 Contributed by Lynx Real-Time Systems, Inc. Los Gatos, CA.
6 This file is part of GDB.
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.
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.
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/>. */
26 #include "breakpoint.h"
31 #include "common/vec.h"
33 /* Frontend view of the thread state. Possible extensions: stepping,
34 finishing, until(ling),... */
42 /* Inferior thread specific part of `struct infcall_control_state'.
44 Inferior process counterpart is `struct inferior_control_state'. */
46 struct thread_control_state
48 /* User/external stepping state. */
50 /* Step-resume or longjmp-resume breakpoint. */
51 struct breakpoint *step_resume_breakpoint;
53 /* Exception-resume breakpoint. */
54 struct breakpoint *exception_resume_breakpoint;
56 /* Breakpoints used for software single stepping. Plural, because
57 it may have multiple locations. E.g., if stepping over a
58 conditional branch instruction we can't decode the condition for,
59 we'll need to put a breakpoint at the branch destination, and
60 another at the instruction after the branch. */
61 struct breakpoint *single_step_breakpoints;
63 /* Range to single step within.
65 If this is nonzero, respond to a single-step signal by continuing
66 to step if the pc is in this range.
68 If step_range_start and step_range_end are both 1, it means to
69 step for a single instruction (FIXME: it might clean up
70 wait_for_inferior in a minor way if this were changed to the
71 address of the instruction and that address plus one. But maybe
73 CORE_ADDR step_range_start; /* Inclusive */
74 CORE_ADDR step_range_end; /* Exclusive */
76 /* Function the thread was in as of last it started stepping. */
77 struct symbol *step_start_function;
79 /* If GDB issues a target step request, and this is nonzero, the
80 target should single-step this thread once, and then continue
81 single-stepping it without GDB core involvement as long as the
82 thread stops in the step range above. If this is zero, the
83 target should ignore the step range, and only issue one single
87 /* Stack frame address as of when stepping command was issued.
88 This is how we know when we step into a subroutine call, and how
89 to set the frame for the breakpoint used to step out. */
90 struct frame_id step_frame_id;
92 /* Similarly, the frame ID of the underlying stack frame (skipping
93 any inlined frames). */
94 struct frame_id step_stack_frame_id;
96 /* Nonzero if we are presently stepping over a breakpoint.
98 If we hit a breakpoint or watchpoint, and then continue, we need
99 to single step the current thread with breakpoints disabled, to
100 avoid hitting the same breakpoint or watchpoint again. And we
101 should step just a single thread and keep other threads stopped,
102 so that other threads don't miss breakpoints while they are
105 So, this variable simultaneously means that we need to single
106 step the current thread, keep other threads stopped, and that
107 breakpoints should be removed while we step.
109 This variable is set either:
110 - in proceed, when we resume inferior on user's explicit request
111 - in keep_going, if handle_inferior_event decides we need to
112 step over breakpoint.
114 The variable is cleared in normal_stop. The proceed calls
115 wait_for_inferior, which calls handle_inferior_event in a loop,
116 and until wait_for_inferior exits, this variable is changed only
120 /* Nonzero if the thread is being proceeded for a "finish" command
121 or a similar situation when return value should be printed. */
122 int proceed_to_finish;
124 /* Nonzero if the thread is being proceeded for an inferior function
128 enum step_over_calls_kind step_over_calls;
130 /* Nonzero if stopped due to a step command. */
133 /* Chain containing status of breakpoint(s) the thread stopped
137 /* The interpreter that issued the execution command. NULL if the
138 thread was resumed as a result of a command applied to some other
139 thread (e.g., "next" with scheduler-locking off). */
140 struct interp *command_interp;
142 /* Whether the command that started the thread was a stepping
143 command. This is used to decide whether "set scheduler-locking
144 step" behaves like "on" or "off". */
145 int stepping_command;
148 /* Inferior thread specific part of `struct infcall_suspend_state'. */
150 struct thread_suspend_state
152 /* Last signal that the inferior received (why it stopped). When
153 the thread is resumed, this signal is delivered. Note: the
154 target should not check whether the signal is in pass state,
155 because the signal may have been explicitly passed with the
156 "signal" command, which overrides "handle nopass". If the signal
157 should be suppressed, the core will take care of clearing this
158 before the target is resumed. */
159 enum gdb_signal stop_signal;
162 typedef struct value *value_ptr;
163 DEF_VEC_P (value_ptr);
164 typedef VEC (value_ptr) value_vec;
168 struct thread_info *next;
169 ptid_t ptid; /* "Actual process id";
170 In fact, this may be overloaded with
171 kernel thread id, etc. */
172 int num; /* Convenient handle (GDB thread id) */
174 /* The name of the thread, as specified by the user. This is NULL
175 if the thread does not have a user-given name. */
178 /* Non-zero means the thread is executing. Note: this is different
179 from saying that there is an active target and we are stopped at
180 a breakpoint, for instance. This is a real indicator whether the
181 thread is off and running. */
184 /* Frontend view of the thread state. Note that the THREAD_RUNNING/
185 THREAD_STOPPED states are different from EXECUTING. When the
186 thread is stopped internally while handling an internal event,
187 like a software single-step breakpoint, EXECUTING will be false,
188 but STATE will still be THREAD_RUNNING. */
189 enum thread_state state;
191 /* If this is > 0, then it means there's code out there that relies
192 on this thread being listed. Don't delete it from the lists even
193 if we detect it exiting. */
196 /* State of GDB control of inferior thread execution.
197 See `struct thread_control_state'. */
198 struct thread_control_state control;
200 /* State of inferior thread to restore after GDB is done with an inferior
201 call. See `struct thread_suspend_state'. */
202 struct thread_suspend_state suspend;
205 struct symtab *current_symtab;
207 /* Internal stepping state. */
209 /* Record the pc of the thread the last time it was resumed. (It
210 can't be done on stop as the PC may change since the last stop,
211 e.g., "return" command, or "p $pc = 0xf000"). This is maintained
212 by proceed and keep_going, and among other things, it's used in
213 adjust_pc_after_break to distinguish a hardware single-step
214 SIGTRAP from a breakpoint SIGTRAP. */
217 /* Did we set the thread stepping a breakpoint instruction? This is
218 used in conjunction with PREV_PC to decide whether to adjust the
220 int stepped_breakpoint;
222 /* Should we step over breakpoint next time keep_going is called? */
223 int stepping_over_breakpoint;
225 /* Should we step over a watchpoint next time keep_going is called?
226 This is needed on targets with non-continuable, non-steppable
228 int stepping_over_watchpoint;
230 /* Set to TRUE if we should finish single-stepping over a breakpoint
231 after hitting the current step-resume breakpoint. The context here
232 is that GDB is to do `next' or `step' while signal arrives.
233 When stepping over a breakpoint and signal arrives, GDB will attempt
234 to skip signal handler, so it inserts a step_resume_breakpoint at the
235 signal return address, and resume inferior.
236 step_after_step_resume_breakpoint is set to TRUE at this moment in
237 order to keep GDB in mind that there is still a breakpoint to step over
238 when GDB gets back SIGTRAP from step_resume_breakpoint. */
239 int step_after_step_resume_breakpoint;
241 /* Per-thread command support. */
243 /* Pointer to what is left to do for an execution command after the
244 target stops. Used only in asynchronous mode, by targets that
245 support async execution. Several execution commands use it. */
246 struct continuation *continuations;
248 /* Similar to the above, but used when a single execution command
249 requires several resume/stop iterations. Used by the step
251 struct continuation *intermediate_continuations;
253 /* If stepping, nonzero means step count is > 1 so don't print frame
254 next time inferior stops if it stops due to stepping. */
257 /* This is used to remember when a fork or vfork event was caught by
258 a catchpoint, and thus the event is to be followed at the next
259 resume of the thread, and not immediately. */
260 struct target_waitstatus pending_follow;
262 /* True if this thread has been explicitly requested to stop. */
265 /* The initiating frame of a nexting operation, used for deciding
266 which exceptions to intercept. If it is null_frame_id no
267 bp_longjmp or bp_exception but longjmp has been caught just for
268 bp_longjmp_call_dummy. */
269 struct frame_id initiating_frame;
271 /* Private data used by the target vector implementation. */
272 struct private_thread_info *priv;
274 /* Function that is called to free PRIVATE. If this is NULL, then
275 xfree will be called on PRIVATE. */
276 void (*private_dtor) (struct private_thread_info *);
278 /* Branch trace information for this thread. */
279 struct btrace_thread_info btrace;
281 /* Flag which indicates that the stack temporaries should be stored while
282 evaluating expressions. */
283 int stack_temporaries_enabled;
285 /* Values that are stored as temporaries on stack while evaluating
287 value_vec *stack_temporaries;
289 /* Step-over chain. A thread is in the step-over queue if these are
290 non-NULL. If only a single thread is in the chain, then these
291 fields point to self. */
292 struct thread_info *step_over_prev;
293 struct thread_info *step_over_next;
296 /* Create an empty thread list, or empty the existing one. */
297 extern void init_thread_list (void);
299 /* Add a thread to the thread list, print a message
300 that a new thread is found, and return the pointer to
301 the new thread. Caller my use this pointer to
302 initialize the private thread data. */
303 extern struct thread_info *add_thread (ptid_t ptid);
305 /* Same as add_thread, but does not print a message
307 extern struct thread_info *add_thread_silent (ptid_t ptid);
309 /* Same as add_thread, and sets the private info. */
310 extern struct thread_info *add_thread_with_info (ptid_t ptid,
311 struct private_thread_info *);
313 /* Delete an existing thread list entry. */
314 extern void delete_thread (ptid_t);
316 /* Delete an existing thread list entry, and be quiet about it. Used
317 after the process this thread having belonged to having already
318 exited, for example. */
319 extern void delete_thread_silent (ptid_t);
321 /* Delete a step_resume_breakpoint from the thread database. */
322 extern void delete_step_resume_breakpoint (struct thread_info *);
324 /* Delete an exception_resume_breakpoint from the thread database. */
325 extern void delete_exception_resume_breakpoint (struct thread_info *);
327 /* Delete the single-step breakpoints of thread TP, if any. */
328 extern void delete_single_step_breakpoints (struct thread_info *tp);
330 /* Check if the thread has software single stepping breakpoints
332 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
334 /* Check whether the thread has software single stepping breakpoints
336 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
337 struct address_space *aspace,
340 /* Translate the integer thread id (GDB's homegrown id, not the system's)
341 into a "pid" (which may be overloaded with extra thread information). */
342 extern ptid_t thread_id_to_pid (int);
344 /* Translate a 'pid' (which may be overloaded with extra thread information)
345 into the integer thread id (GDB's homegrown id, not the system's). */
346 extern int pid_to_thread_id (ptid_t ptid);
348 /* Boolean test for an already-known pid (which may be overloaded with
349 extra thread information). */
350 extern int in_thread_list (ptid_t ptid);
352 /* Boolean test for an already-known thread id (GDB's homegrown id,
353 not the system's). */
354 extern int valid_thread_id (int thread);
356 /* Search function to lookup a thread by 'pid'. */
357 extern struct thread_info *find_thread_ptid (ptid_t ptid);
359 /* Find thread by GDB user-visible thread number. */
360 struct thread_info *find_thread_id (int num);
362 /* Finds the first thread of the inferior given by PID. If PID is -1,
363 returns the first thread in the list. */
364 struct thread_info *first_thread_of_process (int pid);
366 /* Returns any thread of process PID, giving preference to the current
368 extern struct thread_info *any_thread_of_process (int pid);
370 /* Returns any non-exited thread of process PID, giving preference to
371 the current thread, and to not executing threads. */
372 extern struct thread_info *any_live_thread_of_process (int pid);
374 /* Change the ptid of thread OLD_PTID to NEW_PTID. */
375 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
377 /* Iterator function to call a user-provided callback function
378 once for each known thread. */
379 typedef int (*thread_callback_func) (struct thread_info *, void *);
380 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
382 /* Traverse all threads, except those that have THREAD_EXITED
385 #define ALL_NON_EXITED_THREADS(T) \
386 for (T = thread_list; T; T = T->next) \
387 if ((T)->state != THREAD_EXITED)
389 /* Traverse all threads, including those that have THREAD_EXITED
390 state. Allows deleting the currently iterated thread. */
391 #define ALL_THREADS_SAFE(T, TMP) \
392 for ((T) = thread_list; \
393 (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
396 extern int thread_count (void);
398 /* Switch from one thread to another. */
399 extern void switch_to_thread (ptid_t ptid);
401 /* Marks thread PTID is running, or stopped.
402 If PTID is minus_one_ptid, marks all threads. */
403 extern void set_running (ptid_t ptid, int running);
405 /* Marks or clears thread(s) PTID as having been requested to stop.
406 If PTID is MINUS_ONE_PTID, applies to all threads. If
407 ptid_is_pid(PTID) is true, applies to all threads of the process
408 pointed at by PTID. If STOP, then the THREAD_STOP_REQUESTED
409 observer is called with PTID as argument. */
410 extern void set_stop_requested (ptid_t ptid, int stop);
412 /* NOTE: Since the thread state is not a boolean, most times, you do
413 not want to check it with negation. If you really want to check if
414 the thread is stopped,
418 if (is_stopped (ptid))
422 if (!is_running (ptid))
424 The latter also returns true on exited threads, most likelly not
427 /* Reports if in the frontend's perpective, thread PTID is running. */
428 extern int is_running (ptid_t ptid);
430 /* Is this thread listed, but known to have exited? We keep it listed
431 (but not visible) until it's safe to delete. */
432 extern int is_exited (ptid_t ptid);
434 /* In the frontend's perpective, is this thread stopped? */
435 extern int is_stopped (ptid_t ptid);
437 /* Marks thread PTID as executing, or not. If PTID is minus_one_ptid,
440 Note that this is different from the running state. See the
441 description of state and executing fields of struct
443 extern void set_executing (ptid_t ptid, int executing);
445 /* Reports if thread PTID is executing. */
446 extern int is_executing (ptid_t ptid);
448 /* True if any (known or unknown) thread is or may be executing. */
449 extern int threads_are_executing (void);
451 /* Merge the executing property of thread PTID over to its thread
452 state property (frontend running/stopped view).
454 "not executing" -> "stopped"
455 "executing" -> "running"
458 If PTID is minus_one_ptid, go over all threads.
460 Notifications are only emitted if the thread state did change. */
461 extern void finish_thread_state (ptid_t ptid);
463 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
464 registered as a cleanup. PTID_P points to the ptid_t that is
465 passed to FINISH_THREAD_STATE. */
466 extern void finish_thread_state_cleanup (void *ptid_p);
468 /* Commands with a prefix of `thread'. */
469 extern struct cmd_list_element *thread_cmd_list;
471 extern void thread_command (char *tidstr, int from_tty);
473 /* Print notices on thread events (attach, detach, etc.), set with
474 `set print thread-events'. */
475 extern int print_thread_events;
477 extern void print_thread_info (struct ui_out *uiout, char *threads,
480 extern struct cleanup *make_cleanup_restore_current_thread (void);
482 /* Returns a pointer into the thread_info corresponding to
483 INFERIOR_PTID. INFERIOR_PTID *must* be in the thread list. */
484 extern struct thread_info* inferior_thread (void);
486 extern void update_thread_list (void);
488 /* Delete any thread the target says is no longer alive. */
490 extern void prune_threads (void);
492 /* Delete threads marked THREAD_EXITED. Unlike prune_threads, this
493 does not consult the target about whether the thread is alive right
495 extern void delete_exited_threads (void);
497 /* Return true if PC is in the stepping range of THREAD. */
499 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
501 extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid);
503 extern int thread_stack_temporaries_enabled_p (ptid_t ptid);
505 extern void push_thread_stack_temporary (ptid_t ptid, struct value *v);
507 extern struct value *get_last_thread_stack_temporary (ptid_t);
509 extern int value_in_thread_stack_temporaries (struct value *, ptid_t);
511 /* Add TP to the end of its inferior's pending step-over chain. */
513 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
515 /* Remove TP from its inferior's pending step-over chain. */
517 extern void thread_step_over_chain_remove (struct thread_info *tp);
519 /* Return the next thread in the step-over chain starting at TP. NULL
520 if TP is the last entry in the chain. */
522 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
524 /* Return true if TP is in the step-over chain. */
526 extern int thread_is_in_step_over_chain (struct thread_info *tp);
528 extern struct thread_info *thread_list;
530 #endif /* GDBTHREAD_H */