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"
32 #include "target/waitstatus.h"
34 /* Frontend view of the thread state. Possible extensions: stepping,
35 finishing, until(ling),... */
43 /* Inferior thread specific part of `struct infcall_control_state'.
45 Inferior process counterpart is `struct inferior_control_state'. */
47 struct thread_control_state
49 /* User/external stepping state. */
51 /* Step-resume or longjmp-resume breakpoint. */
52 struct breakpoint *step_resume_breakpoint;
54 /* Exception-resume breakpoint. */
55 struct breakpoint *exception_resume_breakpoint;
57 /* Breakpoints used for software single stepping. Plural, because
58 it may have multiple locations. E.g., if stepping over a
59 conditional branch instruction we can't decode the condition for,
60 we'll need to put a breakpoint at the branch destination, and
61 another at the instruction after the branch. */
62 struct breakpoint *single_step_breakpoints;
64 /* Range to single step within.
66 If this is nonzero, respond to a single-step signal by continuing
67 to step if the pc is in this range.
69 If step_range_start and step_range_end are both 1, it means to
70 step for a single instruction (FIXME: it might clean up
71 wait_for_inferior in a minor way if this were changed to the
72 address of the instruction and that address plus one. But maybe
74 CORE_ADDR step_range_start; /* Inclusive */
75 CORE_ADDR step_range_end; /* Exclusive */
77 /* Function the thread was in as of last it started stepping. */
78 struct symbol *step_start_function;
80 /* If GDB issues a target step request, and this is nonzero, the
81 target should single-step this thread once, and then continue
82 single-stepping it without GDB core involvement as long as the
83 thread stops in the step range above. If this is zero, the
84 target should ignore the step range, and only issue one single
88 /* Stack frame address as of when stepping command was issued.
89 This is how we know when we step into a subroutine call, and how
90 to set the frame for the breakpoint used to step out. */
91 struct frame_id step_frame_id;
93 /* Similarly, the frame ID of the underlying stack frame (skipping
94 any inlined frames). */
95 struct frame_id step_stack_frame_id;
97 /* Nonzero if we are presently stepping over a breakpoint.
99 If we hit a breakpoint or watchpoint, and then continue, we need
100 to single step the current thread with breakpoints disabled, to
101 avoid hitting the same breakpoint or watchpoint again. And we
102 should step just a single thread and keep other threads stopped,
103 so that other threads don't miss breakpoints while they are
106 So, this variable simultaneously means that we need to single
107 step the current thread, keep other threads stopped, and that
108 breakpoints should be removed while we step.
110 This variable is set either:
111 - in proceed, when we resume inferior on user's explicit request
112 - in keep_going, if handle_inferior_event decides we need to
113 step over breakpoint.
115 The variable is cleared in normal_stop. The proceed calls
116 wait_for_inferior, which calls handle_inferior_event in a loop,
117 and until wait_for_inferior exits, this variable is changed only
121 /* Nonzero if the thread is being proceeded for a "finish" command
122 or a similar situation when return value should be printed. */
123 int proceed_to_finish;
125 /* Nonzero if the thread is being proceeded for an inferior function
129 enum step_over_calls_kind step_over_calls;
131 /* Nonzero if stopped due to a step command. */
134 /* Chain containing status of breakpoint(s) the thread stopped
138 /* The interpreter that issued the execution command. NULL if the
139 thread was resumed as a result of a command applied to some other
140 thread (e.g., "next" with scheduler-locking off). */
141 struct interp *command_interp;
143 /* Whether the command that started the thread was a stepping
144 command. This is used to decide whether "set scheduler-locking
145 step" behaves like "on" or "off". */
146 int stepping_command;
149 /* Inferior thread specific part of `struct infcall_suspend_state'. */
151 struct thread_suspend_state
153 /* Last signal that the inferior received (why it stopped). When
154 the thread is resumed, this signal is delivered. Note: the
155 target should not check whether the signal is in pass state,
156 because the signal may have been explicitly passed with the
157 "signal" command, which overrides "handle nopass". If the signal
158 should be suppressed, the core will take care of clearing this
159 before the target is resumed. */
160 enum gdb_signal stop_signal;
162 /* The reason the thread last stopped, if we need to track it
163 (breakpoint, watchpoint, etc.) */
164 enum target_stop_reason stop_reason;
166 /* The waitstatus for this thread's last event. */
167 struct target_waitstatus waitstatus;
168 /* If true WAITSTATUS hasn't been handled yet. */
169 int waitstatus_pending_p;
171 /* Record the pc of the thread the last time it stopped. (This is
172 not the current thread's PC as that may have changed since the
173 last stop, e.g., "return" command, or "p $pc = 0xf000"). This is
174 used in coordination with stop_reason and waitstatus_pending_p:
175 if the thread's PC is changed since it last stopped, a pending
176 breakpoint waitstatus is discarded. */
180 typedef struct value *value_ptr;
181 DEF_VEC_P (value_ptr);
182 typedef VEC (value_ptr) value_vec;
186 struct thread_info *next;
187 ptid_t ptid; /* "Actual process id";
188 In fact, this may be overloaded with
189 kernel thread id, etc. */
190 int num; /* Convenient handle (GDB thread id) */
192 /* The name of the thread, as specified by the user. This is NULL
193 if the thread does not have a user-given name. */
196 /* Non-zero means the thread is executing. Note: this is different
197 from saying that there is an active target and we are stopped at
198 a breakpoint, for instance. This is a real indicator whether the
199 thread is off and running. */
202 /* Non-zero if this thread is resumed from infrun's perspective.
203 Note that a thread can be marked both as not-executing and
204 resumed at the same time. This happens if we try to resume a
205 thread that has a wait status pending. We shouldn't let the
206 thread really run until that wait status has been processed, but
207 we should not process that wait status if we didn't try to let
211 /* Frontend view of the thread state. Note that the THREAD_RUNNING/
212 THREAD_STOPPED states are different from EXECUTING. When the
213 thread is stopped internally while handling an internal event,
214 like a software single-step breakpoint, EXECUTING will be false,
215 but STATE will still be THREAD_RUNNING. */
216 enum thread_state state;
218 /* If this is > 0, then it means there's code out there that relies
219 on this thread being listed. Don't delete it from the lists even
220 if we detect it exiting. */
223 /* State of GDB control of inferior thread execution.
224 See `struct thread_control_state'. */
225 struct thread_control_state control;
227 /* State of inferior thread to restore after GDB is done with an inferior
228 call. See `struct thread_suspend_state'. */
229 struct thread_suspend_state suspend;
232 struct symtab *current_symtab;
234 /* Internal stepping state. */
236 /* Record the pc of the thread the last time it was resumed. (It
237 can't be done on stop as the PC may change since the last stop,
238 e.g., "return" command, or "p $pc = 0xf000"). This is maintained
239 by proceed and keep_going, and among other things, it's used in
240 adjust_pc_after_break to distinguish a hardware single-step
241 SIGTRAP from a breakpoint SIGTRAP. */
244 /* Did we set the thread stepping a breakpoint instruction? This is
245 used in conjunction with PREV_PC to decide whether to adjust the
247 int stepped_breakpoint;
249 /* Should we step over breakpoint next time keep_going is called? */
250 int stepping_over_breakpoint;
252 /* Should we step over a watchpoint next time keep_going is called?
253 This is needed on targets with non-continuable, non-steppable
255 int stepping_over_watchpoint;
257 /* Set to TRUE if we should finish single-stepping over a breakpoint
258 after hitting the current step-resume breakpoint. The context here
259 is that GDB is to do `next' or `step' while signal arrives.
260 When stepping over a breakpoint and signal arrives, GDB will attempt
261 to skip signal handler, so it inserts a step_resume_breakpoint at the
262 signal return address, and resume inferior.
263 step_after_step_resume_breakpoint is set to TRUE at this moment in
264 order to keep GDB in mind that there is still a breakpoint to step over
265 when GDB gets back SIGTRAP from step_resume_breakpoint. */
266 int step_after_step_resume_breakpoint;
268 /* Pointer to the state machine manager object that handles what is
269 left to do for the thread's execution command after the target
270 stops. Several execution commands use it. */
271 struct thread_fsm *thread_fsm;
273 /* This is used to remember when a fork or vfork event was caught by
274 a catchpoint, and thus the event is to be followed at the next
275 resume of the thread, and not immediately. */
276 struct target_waitstatus pending_follow;
278 /* True if this thread has been explicitly requested to stop. */
281 /* The initiating frame of a nexting operation, used for deciding
282 which exceptions to intercept. If it is null_frame_id no
283 bp_longjmp or bp_exception but longjmp has been caught just for
284 bp_longjmp_call_dummy. */
285 struct frame_id initiating_frame;
287 /* Private data used by the target vector implementation. */
288 struct private_thread_info *priv;
290 /* Function that is called to free PRIVATE. If this is NULL, then
291 xfree will be called on PRIVATE. */
292 void (*private_dtor) (struct private_thread_info *);
294 /* Branch trace information for this thread. */
295 struct btrace_thread_info btrace;
297 /* Flag which indicates that the stack temporaries should be stored while
298 evaluating expressions. */
299 int stack_temporaries_enabled;
301 /* Values that are stored as temporaries on stack while evaluating
303 value_vec *stack_temporaries;
305 /* Step-over chain. A thread is in the step-over queue if these are
306 non-NULL. If only a single thread is in the chain, then these
307 fields point to self. */
308 struct thread_info *step_over_prev;
309 struct thread_info *step_over_next;
312 /* Create an empty thread list, or empty the existing one. */
313 extern void init_thread_list (void);
315 /* Add a thread to the thread list, print a message
316 that a new thread is found, and return the pointer to
317 the new thread. Caller my use this pointer to
318 initialize the private thread data. */
319 extern struct thread_info *add_thread (ptid_t ptid);
321 /* Same as add_thread, but does not print a message
323 extern struct thread_info *add_thread_silent (ptid_t ptid);
325 /* Same as add_thread, and sets the private info. */
326 extern struct thread_info *add_thread_with_info (ptid_t ptid,
327 struct private_thread_info *);
329 /* Delete an existing thread list entry. */
330 extern void delete_thread (ptid_t);
332 /* Delete an existing thread list entry, and be quiet about it. Used
333 after the process this thread having belonged to having already
334 exited, for example. */
335 extern void delete_thread_silent (ptid_t);
337 /* Delete a step_resume_breakpoint from the thread database. */
338 extern void delete_step_resume_breakpoint (struct thread_info *);
340 /* Delete an exception_resume_breakpoint from the thread database. */
341 extern void delete_exception_resume_breakpoint (struct thread_info *);
343 /* Delete the single-step breakpoints of thread TP, if any. */
344 extern void delete_single_step_breakpoints (struct thread_info *tp);
346 /* Check if the thread has software single stepping breakpoints
348 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
350 /* Check whether the thread has software single stepping breakpoints
352 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
353 struct address_space *aspace,
356 /* Translate the integer thread id (GDB's homegrown id, not the system's)
357 into a "pid" (which may be overloaded with extra thread information). */
358 extern ptid_t thread_id_to_pid (int);
360 /* Translate a 'pid' (which may be overloaded with extra thread information)
361 into the integer thread id (GDB's homegrown id, not the system's). */
362 extern int pid_to_thread_id (ptid_t ptid);
364 /* Boolean test for an already-known pid (which may be overloaded with
365 extra thread information). */
366 extern int in_thread_list (ptid_t ptid);
368 /* Boolean test for an already-known thread id (GDB's homegrown id,
369 not the system's). */
370 extern int valid_thread_id (int thread);
372 /* Search function to lookup a thread by 'pid'. */
373 extern struct thread_info *find_thread_ptid (ptid_t ptid);
375 /* Find thread by GDB user-visible thread number. */
376 struct thread_info *find_thread_id (int num);
378 /* Finds the first thread of the inferior given by PID. If PID is -1,
379 returns the first thread in the list. */
380 struct thread_info *first_thread_of_process (int pid);
382 /* Returns any thread of process PID, giving preference to the current
384 extern struct thread_info *any_thread_of_process (int pid);
386 /* Returns any non-exited thread of process PID, giving preference to
387 the current thread, and to not executing threads. */
388 extern struct thread_info *any_live_thread_of_process (int pid);
390 /* Change the ptid of thread OLD_PTID to NEW_PTID. */
391 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
393 /* Iterator function to call a user-provided callback function
394 once for each known thread. */
395 typedef int (*thread_callback_func) (struct thread_info *, void *);
396 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
398 /* Traverse all threads, except those that have THREAD_EXITED
401 #define ALL_NON_EXITED_THREADS(T) \
402 for (T = thread_list; T; T = T->next) \
403 if ((T)->state != THREAD_EXITED)
405 /* Traverse all threads, including those that have THREAD_EXITED
406 state. Allows deleting the currently iterated thread. */
407 #define ALL_THREADS_SAFE(T, TMP) \
408 for ((T) = thread_list; \
409 (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
412 extern int thread_count (void);
414 /* Switch from one thread to another. */
415 extern void switch_to_thread (ptid_t ptid);
417 /* Marks or clears thread(s) PTID as resumed. If PTID is
418 MINUS_ONE_PTID, applies to all threads. If ptid_is_pid(PTID) is
419 true, applies to all threads of the process pointed at by PTID. */
420 extern void set_resumed (ptid_t ptid, int resumed);
422 /* Marks thread PTID is running, or stopped.
423 If PTID is minus_one_ptid, marks all threads. */
424 extern void set_running (ptid_t ptid, int running);
426 /* Marks or clears thread(s) PTID as having been requested to stop.
427 If PTID is MINUS_ONE_PTID, applies to all threads. If
428 ptid_is_pid(PTID) is true, applies to all threads of the process
429 pointed at by PTID. If STOP, then the THREAD_STOP_REQUESTED
430 observer is called with PTID as argument. */
431 extern void set_stop_requested (ptid_t ptid, int stop);
433 /* NOTE: Since the thread state is not a boolean, most times, you do
434 not want to check it with negation. If you really want to check if
435 the thread is stopped,
439 if (is_stopped (ptid))
443 if (!is_running (ptid))
445 The latter also returns true on exited threads, most likelly not
448 /* Reports if in the frontend's perpective, thread PTID is running. */
449 extern int is_running (ptid_t ptid);
451 /* Is this thread listed, but known to have exited? We keep it listed
452 (but not visible) until it's safe to delete. */
453 extern int is_exited (ptid_t ptid);
455 /* In the frontend's perpective, is this thread stopped? */
456 extern int is_stopped (ptid_t ptid);
458 /* Marks thread PTID as executing, or not. If PTID is minus_one_ptid,
461 Note that this is different from the running state. See the
462 description of state and executing fields of struct
464 extern void set_executing (ptid_t ptid, int executing);
466 /* Reports if thread PTID is executing. */
467 extern int is_executing (ptid_t ptid);
469 /* True if any (known or unknown) thread is or may be executing. */
470 extern int threads_are_executing (void);
472 /* Merge the executing property of thread PTID over to its thread
473 state property (frontend running/stopped view).
475 "not executing" -> "stopped"
476 "executing" -> "running"
479 If PTID is minus_one_ptid, go over all threads.
481 Notifications are only emitted if the thread state did change. */
482 extern void finish_thread_state (ptid_t ptid);
484 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
485 registered as a cleanup. PTID_P points to the ptid_t that is
486 passed to FINISH_THREAD_STATE. */
487 extern void finish_thread_state_cleanup (void *ptid_p);
489 /* Commands with a prefix of `thread'. */
490 extern struct cmd_list_element *thread_cmd_list;
492 extern void thread_command (char *tidstr, int from_tty);
494 /* Print notices on thread events (attach, detach, etc.), set with
495 `set print thread-events'. */
496 extern int print_thread_events;
498 extern void print_thread_info (struct ui_out *uiout, char *threads,
501 extern struct cleanup *make_cleanup_restore_current_thread (void);
503 /* Returns a pointer into the thread_info corresponding to
504 INFERIOR_PTID. INFERIOR_PTID *must* be in the thread list. */
505 extern struct thread_info* inferior_thread (void);
507 extern void update_thread_list (void);
509 /* Delete any thread the target says is no longer alive. */
511 extern void prune_threads (void);
513 /* Delete threads marked THREAD_EXITED. Unlike prune_threads, this
514 does not consult the target about whether the thread is alive right
516 extern void delete_exited_threads (void);
518 /* Return true if PC is in the stepping range of THREAD. */
520 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
522 extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid);
524 extern int thread_stack_temporaries_enabled_p (ptid_t ptid);
526 extern void push_thread_stack_temporary (ptid_t ptid, struct value *v);
528 extern struct value *get_last_thread_stack_temporary (ptid_t);
530 extern int value_in_thread_stack_temporaries (struct value *, ptid_t);
532 /* Add TP to the end of its inferior's pending step-over chain. */
534 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
536 /* Remove TP from its inferior's pending step-over chain. */
538 extern void thread_step_over_chain_remove (struct thread_info *tp);
540 /* Return the next thread in the step-over chain starting at TP. NULL
541 if TP is the last entry in the chain. */
543 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
545 /* Return true if TP is in the step-over chain. */
547 extern int thread_is_in_step_over_chain (struct thread_info *tp);
549 /* Cancel any ongoing execution command. */
551 extern void thread_cancel_execution_command (struct thread_info *thr);
553 extern struct thread_info *thread_list;
555 #endif /* GDBTHREAD_H */