1 /* Multi-process/thread control defs for GDB, the GNU debugger.
2 Copyright (C) 1987-2019 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"
30 #include "common/vec.h"
31 #include "target/waitstatus.h"
32 #include "cli/cli-utils.h"
33 #include "common/refcounted-object.h"
34 #include "common/common-gdbthread.h"
35 #include "common/forward-scope-exit.h"
39 /* Frontend view of the thread state. Possible extensions: stepping,
40 finishing, until(ling),...
42 NOTE: Since the thread state is not a boolean, most times, you do
43 not want to check it with negation. If you really want to check if
44 the thread is stopped,
48 if (tp->state == THREAD_STOPPED)
52 if (tp->state != THREAD_RUNNING)
54 The latter is also true for exited threads, most likely not what
58 /* In the frontend's perpective, the thread is stopped. */
61 /* In the frontend's perpective, the thread is running. */
64 /* The thread is listed, but known to have exited. We keep it
65 listed (but not visible) until it's safe to delete it. */
69 /* STEP_OVER_ALL means step over all subroutine calls.
70 STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
71 STEP_OVER_NONE means don't step over any subroutine calls. */
73 enum step_over_calls_kind
77 STEP_OVER_UNDEBUGGABLE
80 /* Inferior thread specific part of `struct infcall_control_state'.
82 Inferior process counterpart is `struct inferior_control_state'. */
84 struct thread_control_state
86 /* User/external stepping state. */
88 /* Step-resume or longjmp-resume breakpoint. */
89 struct breakpoint *step_resume_breakpoint = nullptr;
91 /* Exception-resume breakpoint. */
92 struct breakpoint *exception_resume_breakpoint = nullptr;
94 /* Breakpoints used for software single stepping. Plural, because
95 it may have multiple locations. E.g., if stepping over a
96 conditional branch instruction we can't decode the condition for,
97 we'll need to put a breakpoint at the branch destination, and
98 another at the instruction after the branch. */
99 struct breakpoint *single_step_breakpoints = nullptr;
101 /* Range to single step within.
103 If this is nonzero, respond to a single-step signal by continuing
104 to step if the pc is in this range.
106 If step_range_start and step_range_end are both 1, it means to
107 step for a single instruction (FIXME: it might clean up
108 wait_for_inferior in a minor way if this were changed to the
109 address of the instruction and that address plus one. But maybe
111 CORE_ADDR step_range_start = 0; /* Inclusive */
112 CORE_ADDR step_range_end = 0; /* Exclusive */
114 /* Function the thread was in as of last it started stepping. */
115 struct symbol *step_start_function = nullptr;
117 /* If GDB issues a target step request, and this is nonzero, the
118 target should single-step this thread once, and then continue
119 single-stepping it without GDB core involvement as long as the
120 thread stops in the step range above. If this is zero, the
121 target should ignore the step range, and only issue one single
123 int may_range_step = 0;
125 /* Stack frame address as of when stepping command was issued.
126 This is how we know when we step into a subroutine call, and how
127 to set the frame for the breakpoint used to step out. */
128 struct frame_id step_frame_id {};
130 /* Similarly, the frame ID of the underlying stack frame (skipping
131 any inlined frames). */
132 struct frame_id step_stack_frame_id {};
134 /* Nonzero if we are presently stepping over a breakpoint.
136 If we hit a breakpoint or watchpoint, and then continue, we need
137 to single step the current thread with breakpoints disabled, to
138 avoid hitting the same breakpoint or watchpoint again. And we
139 should step just a single thread and keep other threads stopped,
140 so that other threads don't miss breakpoints while they are
143 So, this variable simultaneously means that we need to single
144 step the current thread, keep other threads stopped, and that
145 breakpoints should be removed while we step.
147 This variable is set either:
148 - in proceed, when we resume inferior on user's explicit request
149 - in keep_going, if handle_inferior_event decides we need to
150 step over breakpoint.
152 The variable is cleared in normal_stop. The proceed calls
153 wait_for_inferior, which calls handle_inferior_event in a loop,
154 and until wait_for_inferior exits, this variable is changed only
156 int trap_expected = 0;
158 /* Nonzero if the thread is being proceeded for a "finish" command
159 or a similar situation when return value should be printed. */
160 int proceed_to_finish = 0;
162 /* Nonzero if the thread is being proceeded for an inferior function
166 enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
168 /* Nonzero if stopped due to a step command. */
171 /* Chain containing status of breakpoint(s) the thread stopped
173 bpstat stop_bpstat = nullptr;
175 /* Whether the command that started the thread was a stepping
176 command. This is used to decide whether "set scheduler-locking
177 step" behaves like "on" or "off". */
178 int stepping_command = 0;
181 /* Inferior thread specific part of `struct infcall_suspend_state'. */
183 struct thread_suspend_state
185 /* Last signal that the inferior received (why it stopped). When
186 the thread is resumed, this signal is delivered. Note: the
187 target should not check whether the signal is in pass state,
188 because the signal may have been explicitly passed with the
189 "signal" command, which overrides "handle nopass". If the signal
190 should be suppressed, the core will take care of clearing this
191 before the target is resumed. */
192 enum gdb_signal stop_signal = GDB_SIGNAL_0;
194 /* The reason the thread last stopped, if we need to track it
195 (breakpoint, watchpoint, etc.) */
196 enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
198 /* The waitstatus for this thread's last event. */
199 struct target_waitstatus waitstatus {};
200 /* If true WAITSTATUS hasn't been handled yet. */
201 int waitstatus_pending_p = 0;
203 /* Record the pc of the thread the last time it stopped. (This is
204 not the current thread's PC as that may have changed since the
205 last stop, e.g., "return" command, or "p $pc = 0xf000").
207 - If the thread's PC has not changed since the thread last
208 stopped, then proceed skips a breakpoint at the current PC,
209 otherwise we let the thread run into the breakpoint.
211 - If the thread has an unprocessed event pending, as indicated by
212 waitstatus_pending_p, this is used in coordination with
213 stop_reason: if the thread's PC has changed since the thread
214 last stopped, a pending breakpoint waitstatus is discarded.
216 - If the thread is running, this is set to -1, to avoid leaving
217 it with a stale value, to make it easier to catch bugs. */
218 CORE_ADDR stop_pc = 0;
221 /* Base class for target-specific thread data. */
222 struct private_thread_info
224 virtual ~private_thread_info () = 0;
227 /* Threads are intrusively refcounted objects. Being the
228 user-selected thread is normally considered an implicit strong
229 reference and is thus not accounted in the refcount, unlike
230 inferior objects. This is necessary, because there's no "current
231 thread" pointer. Instead the current thread is inferred from the
232 inferior_ptid global. However, when GDB needs to remember the
233 selected thread to later restore it, GDB bumps the thread object's
234 refcount, to prevent something deleting the thread object before
235 reverting back (e.g., due to a "kill" command). If the thread
236 meanwhile exits before being re-selected, then the thread object is
237 left listed in the thread list, but marked with state
238 THREAD_EXITED. (See scoped_restore_current_thread and
239 delete_thread). All other thread references are considered weak
240 references. Placing a thread in the thread list is an implicit
241 strong reference, and is thus not accounted for in the thread's
244 class thread_info : public refcounted_object
247 explicit thread_info (inferior *inf, ptid_t ptid);
250 bool deletable () const;
252 /* Mark this thread as running and notify observers. */
253 void set_running (bool running);
255 struct thread_info *next = NULL;
256 ptid_t ptid; /* "Actual process id";
257 In fact, this may be overloaded with
258 kernel thread id, etc. */
260 /* Each thread has two GDB IDs.
262 a) The thread ID (Id). This consists of the pair of:
264 - the number of the thread's inferior and,
266 - the thread's thread number in its inferior, aka, the
267 per-inferior thread number. This number is unique in the
268 inferior but not unique between inferiors.
270 b) The global ID (GId). This is a a single integer unique
271 between all inferiors.
275 (gdb) info threads -gid
276 Id GId Target Id Frame
277 * 1.1 1 Thread A 0x16a09237 in foo () at foo.c:10
278 1.2 3 Thread B 0x15ebc6ed in bar () at foo.c:20
279 1.3 5 Thread C 0x15ebc6ed in bar () at foo.c:20
280 2.1 2 Thread A 0x16a09237 in foo () at foo.c:10
281 2.2 4 Thread B 0x15ebc6ed in bar () at foo.c:20
282 2.3 6 Thread C 0x15ebc6ed in bar () at foo.c:20
284 Above, both inferiors 1 and 2 have threads numbered 1-3, but each
285 thread has its own unique global ID. */
287 /* The thread's global GDB thread number. This is exposed to MI,
288 Python/Scheme, visible with "info threads -gid", and is also what
289 the $_gthread convenience variable is bound to. */
292 /* The per-inferior thread number. This is unique in the inferior
293 the thread belongs to, but not unique between inferiors. This is
294 what the $_thread convenience variable is bound to. */
297 /* The inferior this thread belongs to. */
298 struct inferior *inf;
300 /* The name of the thread, as specified by the user. This is NULL
301 if the thread does not have a user-given name. */
304 /* Non-zero means the thread is executing. Note: this is different
305 from saying that there is an active target and we are stopped at
306 a breakpoint, for instance. This is a real indicator whether the
307 thread is off and running. */
310 /* Non-zero if this thread is resumed from infrun's perspective.
311 Note that a thread can be marked both as not-executing and
312 resumed at the same time. This happens if we try to resume a
313 thread that has a wait status pending. We shouldn't let the
314 thread really run until that wait status has been processed, but
315 we should not process that wait status if we didn't try to let
319 /* Frontend view of the thread state. Note that the THREAD_RUNNING/
320 THREAD_STOPPED states are different from EXECUTING. When the
321 thread is stopped internally while handling an internal event,
322 like a software single-step breakpoint, EXECUTING will be false,
323 but STATE will still be THREAD_RUNNING. */
324 enum thread_state state = THREAD_STOPPED;
326 /* State of GDB control of inferior thread execution.
327 See `struct thread_control_state'. */
328 thread_control_state control;
330 /* State of inferior thread to restore after GDB is done with an inferior
331 call. See `struct thread_suspend_state'. */
332 thread_suspend_state suspend;
334 int current_line = 0;
335 struct symtab *current_symtab = NULL;
337 /* Internal stepping state. */
339 /* Record the pc of the thread the last time it was resumed. (It
340 can't be done on stop as the PC may change since the last stop,
341 e.g., "return" command, or "p $pc = 0xf000"). This is maintained
342 by proceed and keep_going, and among other things, it's used in
343 adjust_pc_after_break to distinguish a hardware single-step
344 SIGTRAP from a breakpoint SIGTRAP. */
345 CORE_ADDR prev_pc = 0;
347 /* Did we set the thread stepping a breakpoint instruction? This is
348 used in conjunction with PREV_PC to decide whether to adjust the
350 int stepped_breakpoint = 0;
352 /* Should we step over breakpoint next time keep_going is called? */
353 int stepping_over_breakpoint = 0;
355 /* Should we step over a watchpoint next time keep_going is called?
356 This is needed on targets with non-continuable, non-steppable
358 int stepping_over_watchpoint = 0;
360 /* Set to TRUE if we should finish single-stepping over a breakpoint
361 after hitting the current step-resume breakpoint. The context here
362 is that GDB is to do `next' or `step' while signal arrives.
363 When stepping over a breakpoint and signal arrives, GDB will attempt
364 to skip signal handler, so it inserts a step_resume_breakpoint at the
365 signal return address, and resume inferior.
366 step_after_step_resume_breakpoint is set to TRUE at this moment in
367 order to keep GDB in mind that there is still a breakpoint to step over
368 when GDB gets back SIGTRAP from step_resume_breakpoint. */
369 int step_after_step_resume_breakpoint = 0;
371 /* Pointer to the state machine manager object that handles what is
372 left to do for the thread's execution command after the target
373 stops. Several execution commands use it. */
374 struct thread_fsm *thread_fsm = NULL;
376 /* This is used to remember when a fork or vfork event was caught by
377 a catchpoint, and thus the event is to be followed at the next
378 resume of the thread, and not immediately. */
379 struct target_waitstatus pending_follow;
381 /* True if this thread has been explicitly requested to stop. */
382 int stop_requested = 0;
384 /* The initiating frame of a nexting operation, used for deciding
385 which exceptions to intercept. If it is null_frame_id no
386 bp_longjmp or bp_exception but longjmp has been caught just for
387 bp_longjmp_call_dummy. */
388 struct frame_id initiating_frame = null_frame_id;
390 /* Private data used by the target vector implementation. */
391 std::unique_ptr<private_thread_info> priv;
393 /* Branch trace information for this thread. */
394 struct btrace_thread_info btrace {};
396 /* Flag which indicates that the stack temporaries should be stored while
397 evaluating expressions. */
398 bool stack_temporaries_enabled = false;
400 /* Values that are stored as temporaries on stack while evaluating
402 std::vector<struct value *> stack_temporaries;
404 /* Step-over chain. A thread is in the step-over queue if these are
405 non-NULL. If only a single thread is in the chain, then these
406 fields point to self. */
407 struct thread_info *step_over_prev = NULL;
408 struct thread_info *step_over_next = NULL;
411 /* A gdb::ref_ptr pointer to a thread_info. */
413 using thread_info_ref
414 = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
416 /* Create an empty thread list, or empty the existing one. */
417 extern void init_thread_list (void);
419 /* Add a thread to the thread list, print a message
420 that a new thread is found, and return the pointer to
421 the new thread. Caller my use this pointer to
422 initialize the private thread data. */
423 extern struct thread_info *add_thread (ptid_t ptid);
425 /* Same as add_thread, but does not print a message
427 extern struct thread_info *add_thread_silent (ptid_t ptid);
429 /* Same as add_thread, and sets the private info. */
430 extern struct thread_info *add_thread_with_info (ptid_t ptid,
431 struct private_thread_info *);
433 /* Delete an existing thread list entry. */
434 extern void delete_thread (struct thread_info *thread);
436 /* Delete an existing thread list entry, and be quiet about it. Used
437 after the process this thread having belonged to having already
438 exited, for example. */
439 extern void delete_thread_silent (struct thread_info *thread);
441 /* Delete a step_resume_breakpoint from the thread database. */
442 extern void delete_step_resume_breakpoint (struct thread_info *);
444 /* Delete an exception_resume_breakpoint from the thread database. */
445 extern void delete_exception_resume_breakpoint (struct thread_info *);
447 /* Delete the single-step breakpoints of thread TP, if any. */
448 extern void delete_single_step_breakpoints (struct thread_info *tp);
450 /* Check if the thread has software single stepping breakpoints
452 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
454 /* Check whether the thread has software single stepping breakpoints
456 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
457 const address_space *aspace,
460 /* Returns whether to show inferior-qualified thread IDs, or plain
461 thread numbers. Inferior-qualified IDs are shown whenever we have
462 multiple inferiors, or the only inferior left has number > 1. */
463 extern int show_inferior_qualified_tids (void);
465 /* Return a string version of THR's thread ID. If there are multiple
466 inferiors, then this prints the inferior-qualifier form, otherwise
467 it only prints the thread number. The result is stored in a
468 circular static buffer, NUMCELLS deep. */
469 const char *print_thread_id (struct thread_info *thr);
471 /* Boolean test for an already-known ptid. */
472 extern int in_thread_list (ptid_t ptid);
474 /* Boolean test for an already-known global thread id (GDB's homegrown
475 global id, not the system's). */
476 extern int valid_global_thread_id (int global_id);
478 /* Search function to lookup a thread by 'pid'. */
479 extern struct thread_info *find_thread_ptid (ptid_t ptid);
481 /* Search function to lookup a thread by 'ptid'. Only searches in
483 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
485 /* Find thread by GDB global thread ID. */
486 struct thread_info *find_thread_global_id (int global_id);
488 /* Find thread by thread library specific handle in inferior INF. */
489 struct thread_info *find_thread_by_handle
490 (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
492 /* Finds the first thread of the specified inferior. */
493 extern struct thread_info *first_thread_of_inferior (inferior *inf);
495 /* Returns any thread of inferior INF, giving preference to the
497 extern struct thread_info *any_thread_of_inferior (inferior *inf);
499 /* Returns any non-exited thread of inferior INF, giving preference to
500 the current thread, and to not executing threads. */
501 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
503 /* Change the ptid of thread OLD_PTID to NEW_PTID. */
504 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
506 /* Iterator function to call a user-provided callback function
507 once for each known thread. */
508 typedef int (*thread_callback_func) (struct thread_info *, void *);
509 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
511 /* Pull in the internals of the inferiors/threads ranges and
512 iterators. Must be done after struct thread_info is defined. */
513 #include "thread-iter.h"
515 /* Return a range that can be used to walk over all threads of all
516 inferiors, with range-for. Used like this:
518 for (thread_info *thr : all_threads ())
521 inline all_threads_range
527 /* Likewise, but accept a filter PTID. */
529 inline all_matching_threads_range
530 all_threads (ptid_t filter_ptid)
532 return all_matching_threads_range (filter_ptid);
535 /* Return a range that can be used to walk over all non-exited threads
536 of all inferiors, with range-for. FILTER_PTID can be used to
537 filter out thread that don't match. */
539 inline all_non_exited_threads_range
540 all_non_exited_threads (ptid_t filter_ptid = minus_one_ptid)
542 return all_non_exited_threads_range (filter_ptid);
545 /* Return a range that can be used to walk over all threads of all
546 inferiors, with range-for, safely. I.e., it is safe to delete the
547 currently-iterated thread. When combined with range-for, this
548 allow convenient patterns like this:
550 for (thread_info *t : all_threads_safe ())
551 if (some_condition ())
555 inline all_threads_safe_range
558 return all_threads_safe_range ();
561 extern int thread_count (void);
563 /* Return true if we have any thread in any inferior. */
564 extern bool any_thread_p ();
566 /* Switch context to thread THR. Also sets the STOP_PC global. */
567 extern void switch_to_thread (struct thread_info *thr);
569 /* Switch context to no thread selected. */
570 extern void switch_to_no_thread ();
572 /* Switch from one thread to another. Does not read registers. */
573 extern void switch_to_thread_no_regs (struct thread_info *thread);
575 /* Marks or clears thread(s) PTID as resumed. If PTID is
576 MINUS_ONE_PTID, applies to all threads. If ptid_is_pid(PTID) is
577 true, applies to all threads of the process pointed at by PTID. */
578 extern void set_resumed (ptid_t ptid, int resumed);
580 /* Marks thread PTID is running, or stopped.
581 If PTID is minus_one_ptid, marks all threads. */
582 extern void set_running (ptid_t ptid, int running);
584 /* Marks or clears thread(s) PTID as having been requested to stop.
585 If PTID is MINUS_ONE_PTID, applies to all threads. If
586 ptid_is_pid(PTID) is true, applies to all threads of the process
587 pointed at by PTID. If STOP, then the THREAD_STOP_REQUESTED
588 observer is called with PTID as argument. */
589 extern void set_stop_requested (ptid_t ptid, int stop);
591 /* Marks thread PTID as executing, or not. If PTID is minus_one_ptid,
594 Note that this is different from the running state. See the
595 description of state and executing fields of struct
597 extern void set_executing (ptid_t ptid, int executing);
599 /* True if any (known or unknown) thread is or may be executing. */
600 extern int threads_are_executing (void);
602 /* Merge the executing property of thread PTID over to its thread
603 state property (frontend running/stopped view).
605 "not executing" -> "stopped"
606 "executing" -> "running"
609 If PTID is minus_one_ptid, go over all threads.
611 Notifications are only emitted if the thread state did change. */
612 extern void finish_thread_state (ptid_t ptid);
614 /* Calls finish_thread_state on scope exit, unless release() is called
616 using scoped_finish_thread_state
617 = FORWARD_SCOPE_EXIT (finish_thread_state);
619 /* Commands with a prefix of `thread'. */
620 extern struct cmd_list_element *thread_cmd_list;
622 extern void thread_command (const char *tidstr, int from_tty);
624 /* Print notices on thread events (attach, detach, etc.), set with
625 `set print thread-events'. */
626 extern int print_thread_events;
628 /* Prints the list of threads and their details on UIOUT. If
629 REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
630 print threads whose ID is included in the list. If PID is not -1,
631 only print threads from the process PID. Otherwise, threads from
632 all attached PIDs are printed. If both REQUESTED_THREADS is not
633 NULL and PID is not -1, then the thread is printed if it belongs to
634 the specified process. Otherwise, an error is raised. */
635 extern void print_thread_info (struct ui_out *uiout,
636 const char *requested_threads,
639 /* Save/restore current inferior/thread/frame. */
641 class scoped_restore_current_thread
644 scoped_restore_current_thread ();
645 ~scoped_restore_current_thread ();
647 DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
650 /* Use the "class" keyword here, because of a clash with a "thread_info"
651 function in the Darwin API. */
652 class thread_info *m_thread;
654 frame_id m_selected_frame_id;
655 int m_selected_frame_level;
659 /* Returns a pointer into the thread_info corresponding to
660 INFERIOR_PTID. INFERIOR_PTID *must* be in the thread list. */
661 extern struct thread_info* inferior_thread (void);
663 extern void update_thread_list (void);
665 /* Delete any thread the target says is no longer alive. */
667 extern void prune_threads (void);
669 /* Delete threads marked THREAD_EXITED. Unlike prune_threads, this
670 does not consult the target about whether the thread is alive right
672 extern void delete_exited_threads (void);
674 /* Return true if PC is in the stepping range of THREAD. */
676 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
678 /* Enable storing stack temporaries for thread THR and disable and
679 clear the stack temporaries on destruction. Holds a strong
682 class enable_thread_stack_temporaries
686 explicit enable_thread_stack_temporaries (struct thread_info *thr)
689 gdb_assert (m_thr != NULL);
693 m_thr->stack_temporaries_enabled = true;
694 m_thr->stack_temporaries.clear ();
697 ~enable_thread_stack_temporaries ()
699 m_thr->stack_temporaries_enabled = false;
700 m_thr->stack_temporaries.clear ();
705 DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
709 struct thread_info *m_thr;
712 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
714 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
716 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
718 extern bool value_in_thread_stack_temporaries (struct value *,
719 struct thread_info *thr);
721 /* Add TP to the end of its inferior's pending step-over chain. */
723 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
725 /* Remove TP from its inferior's pending step-over chain. */
727 extern void thread_step_over_chain_remove (struct thread_info *tp);
729 /* Return the next thread in the step-over chain starting at TP. NULL
730 if TP is the last entry in the chain. */
732 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
734 /* Return true if TP is in the step-over chain. */
736 extern int thread_is_in_step_over_chain (struct thread_info *tp);
738 /* Cancel any ongoing execution command. */
740 extern void thread_cancel_execution_command (struct thread_info *thr);
742 /* Check whether it makes sense to access a register of the current
743 thread at this point. If not, throw an error (e.g., the thread is
745 extern void validate_registers_access (void);
747 /* Check whether it makes sense to access a register of THREAD at this point.
748 Returns true if registers may be accessed; false otherwise. */
749 extern bool can_access_registers_thread (struct thread_info *thread);
751 /* Returns whether to show which thread hit the breakpoint, received a
752 signal, etc. and ended up causing a user-visible stop. This is
753 true iff we ever detected multiple threads. */
754 extern int show_thread_that_caused_stop (void);
756 /* Print the message for a thread or/and frame selected. */
757 extern void print_selected_thread_frame (struct ui_out *uiout,
758 user_selected_what selection);
760 /* Helper for the CLI's "thread" command and for MI's -thread-select.
761 Selects thread THR. TIDSTR is the original string the thread ID
762 was parsed from. This is used in the error message if THR is not
764 extern void thread_select (const char *tidstr, class thread_info *thr);
766 #endif /* GDBTHREAD_H */