d425664
[binutils-gdb.git] /
1 /* Target-struct-independent code to start (run) and stop an inferior
2 process.
3
4 Copyright (C) 1986-2017 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
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.
12
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.
17
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/>. */
20
21 #include "defs.h"
22 #include "infrun.h"
23 #include <ctype.h>
24 #include "symtab.h"
25 #include "frame.h"
26 #include "inferior.h"
27 #include "breakpoint.h"
28 #include "gdb_wait.h"
29 #include "gdbcore.h"
30 #include "gdbcmd.h"
31 #include "cli/cli-script.h"
32 #include "target.h"
33 #include "gdbthread.h"
34 #include "annotate.h"
35 #include "symfile.h"
36 #include "top.h"
37 #include <signal.h>
38 #include "inf-loop.h"
39 #include "regcache.h"
40 #include "value.h"
41 #include "observer.h"
42 #include "language.h"
43 #include "solib.h"
44 #include "main.h"
45 #include "dictionary.h"
46 #include "block.h"
47 #include "mi/mi-common.h"
48 #include "event-top.h"
49 #include "record.h"
50 #include "record-full.h"
51 #include "inline-frame.h"
52 #include "jit.h"
53 #include "tracepoint.h"
54 #include "continuations.h"
55 #include "interps.h"
56 #include "skip.h"
57 #include "probe.h"
58 #include "objfiles.h"
59 #include "completer.h"
60 #include "target-descriptions.h"
61 #include "target-dcache.h"
62 #include "terminal.h"
63 #include "solist.h"
64 #include "event-loop.h"
65 #include "thread-fsm.h"
66 #include "common/enum-flags.h"
67 #include "progspace-and-thread.h"
68 #include "common/gdb_optional.h"
69 #include "arch-utils.h"
70
71 /* Prototypes for local functions */
72
73 static void info_signals_command (char *, int);
74
75 static void handle_command (char *, int);
76
77 static void sig_print_info (enum gdb_signal);
78
79 static void sig_print_header (void);
80
81 static void resume_cleanups (void *);
82
83 static int follow_fork (void);
84
85 static int follow_fork_inferior (int follow_child, int detach_fork);
86
87 static void follow_inferior_reset_breakpoints (void);
88
89 static void set_schedlock_func (char *args, int from_tty,
90 struct cmd_list_element *c);
91
92 static int currently_stepping (struct thread_info *tp);
93
94 void nullify_last_target_wait_ptid (void);
95
96 static void insert_hp_step_resume_breakpoint_at_frame (struct frame_info *);
97
98 static void insert_step_resume_breakpoint_at_caller (struct frame_info *);
99
100 static void insert_longjmp_resume_breakpoint (struct gdbarch *, CORE_ADDR);
101
102 static int maybe_software_singlestep (struct gdbarch *gdbarch, CORE_ADDR pc);
103
104 /* Asynchronous signal handler registered as event loop source for
105 when we have pending events ready to be passed to the core. */
106 static struct async_event_handler *infrun_async_inferior_event_token;
107
108 /* Stores whether infrun_async was previously enabled or disabled.
109 Starts off as -1, indicating "never enabled/disabled". */
110 static int infrun_is_async = -1;
111
112 /* See infrun.h. */
113
114 void
115 infrun_async (int enable)
116 {
117 if (infrun_is_async != enable)
118 {
119 infrun_is_async = enable;
120
121 if (debug_infrun)
122 fprintf_unfiltered (gdb_stdlog,
123 "infrun: infrun_async(%d)\n",
124 enable);
125
126 if (enable)
127 mark_async_event_handler (infrun_async_inferior_event_token);
128 else
129 clear_async_event_handler (infrun_async_inferior_event_token);
130 }
131 }
132
133 /* See infrun.h. */
134
135 void
136 mark_infrun_async_event_handler (void)
137 {
138 mark_async_event_handler (infrun_async_inferior_event_token);
139 }
140
141 /* When set, stop the 'step' command if we enter a function which has
142 no line number information. The normal behavior is that we step
143 over such function. */
144 int step_stop_if_no_debug = 0;
145 static void
146 show_step_stop_if_no_debug (struct ui_file *file, int from_tty,
147 struct cmd_list_element *c, const char *value)
148 {
149 fprintf_filtered (file, _("Mode of the step operation is %s.\n"), value);
150 }
151
152 /* proceed and normal_stop use this to notify the user when the
153 inferior stopped in a different thread than it had been running
154 in. */
155
156 static ptid_t previous_inferior_ptid;
157
158 /* If set (default for legacy reasons), when following a fork, GDB
159 will detach from one of the fork branches, child or parent.
160 Exactly which branch is detached depends on 'set follow-fork-mode'
161 setting. */
162
163 static int detach_fork = 1;
164
165 int debug_displaced = 0;
166 static void
167 show_debug_displaced (struct ui_file *file, int from_tty,
168 struct cmd_list_element *c, const char *value)
169 {
170 fprintf_filtered (file, _("Displace stepping debugging is %s.\n"), value);
171 }
172
173 unsigned int debug_infrun = 0;
174 static void
175 show_debug_infrun (struct ui_file *file, int from_tty,
176 struct cmd_list_element *c, const char *value)
177 {
178 fprintf_filtered (file, _("Inferior debugging is %s.\n"), value);
179 }
180
181
182 /* Support for disabling address space randomization. */
183
184 int disable_randomization = 1;
185
186 static void
187 show_disable_randomization (struct ui_file *file, int from_tty,
188 struct cmd_list_element *c, const char *value)
189 {
190 if (target_supports_disable_randomization ())
191 fprintf_filtered (file,
192 _("Disabling randomization of debuggee's "
193 "virtual address space is %s.\n"),
194 value);
195 else
196 fputs_filtered (_("Disabling randomization of debuggee's "
197 "virtual address space is unsupported on\n"
198 "this platform.\n"), file);
199 }
200
201 static void
202 set_disable_randomization (char *args, int from_tty,
203 struct cmd_list_element *c)
204 {
205 if (!target_supports_disable_randomization ())
206 error (_("Disabling randomization of debuggee's "
207 "virtual address space is unsupported on\n"
208 "this platform."));
209 }
210
211 /* User interface for non-stop mode. */
212
213 int non_stop = 0;
214 static int non_stop_1 = 0;
215
216 static void
217 set_non_stop (char *args, int from_tty,
218 struct cmd_list_element *c)
219 {
220 if (target_has_execution)
221 {
222 non_stop_1 = non_stop;
223 error (_("Cannot change this setting while the inferior is running."));
224 }
225
226 non_stop = non_stop_1;
227 }
228
229 static void
230 show_non_stop (struct ui_file *file, int from_tty,
231 struct cmd_list_element *c, const char *value)
232 {
233 fprintf_filtered (file,
234 _("Controlling the inferior in non-stop mode is %s.\n"),
235 value);
236 }
237
238 /* "Observer mode" is somewhat like a more extreme version of
239 non-stop, in which all GDB operations that might affect the
240 target's execution have been disabled. */
241
242 int observer_mode = 0;
243 static int observer_mode_1 = 0;
244
245 static void
246 set_observer_mode (char *args, int from_tty,
247 struct cmd_list_element *c)
248 {
249 if (target_has_execution)
250 {
251 observer_mode_1 = observer_mode;
252 error (_("Cannot change this setting while the inferior is running."));
253 }
254
255 observer_mode = observer_mode_1;
256
257 may_write_registers = !observer_mode;
258 may_write_memory = !observer_mode;
259 may_insert_breakpoints = !observer_mode;
260 may_insert_tracepoints = !observer_mode;
261 /* We can insert fast tracepoints in or out of observer mode,
262 but enable them if we're going into this mode. */
263 if (observer_mode)
264 may_insert_fast_tracepoints = 1;
265 may_stop = !observer_mode;
266 update_target_permissions ();
267
268 /* Going *into* observer mode we must force non-stop, then
269 going out we leave it that way. */
270 if (observer_mode)
271 {
272 pagination_enabled = 0;
273 non_stop = non_stop_1 = 1;
274 }
275
276 if (from_tty)
277 printf_filtered (_("Observer mode is now %s.\n"),
278 (observer_mode ? "on" : "off"));
279 }
280
281 static void
282 show_observer_mode (struct ui_file *file, int from_tty,
283 struct cmd_list_element *c, const char *value)
284 {
285 fprintf_filtered (file, _("Observer mode is %s.\n"), value);
286 }
287
288 /* This updates the value of observer mode based on changes in
289 permissions. Note that we are deliberately ignoring the values of
290 may-write-registers and may-write-memory, since the user may have
291 reason to enable these during a session, for instance to turn on a
292 debugging-related global. */
293
294 void
295 update_observer_mode (void)
296 {
297 int newval;
298
299 newval = (!may_insert_breakpoints
300 && !may_insert_tracepoints
301 && may_insert_fast_tracepoints
302 && !may_stop
303 && non_stop);
304
305 /* Let the user know if things change. */
306 if (newval != observer_mode)
307 printf_filtered (_("Observer mode is now %s.\n"),
308 (newval ? "on" : "off"));
309
310 observer_mode = observer_mode_1 = newval;
311 }
312
313 /* Tables of how to react to signals; the user sets them. */
314
315 static unsigned char *signal_stop;
316 static unsigned char *signal_print;
317 static unsigned char *signal_program;
318
319 /* Table of signals that are registered with "catch signal". A
320 non-zero entry indicates that the signal is caught by some "catch
321 signal" command. This has size GDB_SIGNAL_LAST, to accommodate all
322 signals. */
323 static unsigned char *signal_catch;
324
325 /* Table of signals that the target may silently handle.
326 This is automatically determined from the flags above,
327 and simply cached here. */
328 static unsigned char *signal_pass;
329
330 #define SET_SIGS(nsigs,sigs,flags) \
331 do { \
332 int signum = (nsigs); \
333 while (signum-- > 0) \
334 if ((sigs)[signum]) \
335 (flags)[signum] = 1; \
336 } while (0)
337
338 #define UNSET_SIGS(nsigs,sigs,flags) \
339 do { \
340 int signum = (nsigs); \
341 while (signum-- > 0) \
342 if ((sigs)[signum]) \
343 (flags)[signum] = 0; \
344 } while (0)
345
346 /* Update the target's copy of SIGNAL_PROGRAM. The sole purpose of
347 this function is to avoid exporting `signal_program'. */
348
349 void
350 update_signals_program_target (void)
351 {
352 target_program_signals ((int) GDB_SIGNAL_LAST, signal_program);
353 }
354
355 /* Value to pass to target_resume() to cause all threads to resume. */
356
357 #define RESUME_ALL minus_one_ptid
358
359 /* Command list pointer for the "stop" placeholder. */
360
361 static struct cmd_list_element *stop_command;
362
363 /* Nonzero if we want to give control to the user when we're notified
364 of shared library events by the dynamic linker. */
365 int stop_on_solib_events;
366
367 /* Enable or disable optional shared library event breakpoints
368 as appropriate when the above flag is changed. */
369
370 static void
371 set_stop_on_solib_events (char *args, int from_tty, struct cmd_list_element *c)
372 {
373 update_solib_breakpoints ();
374 }
375
376 static void
377 show_stop_on_solib_events (struct ui_file *file, int from_tty,
378 struct cmd_list_element *c, const char *value)
379 {
380 fprintf_filtered (file, _("Stopping for shared library events is %s.\n"),
381 value);
382 }
383
384 /* Nonzero after stop if current stack frame should be printed. */
385
386 static int stop_print_frame;
387
388 /* This is a cached copy of the pid/waitstatus of the last event
389 returned by target_wait()/deprecated_target_wait_hook(). This
390 information is returned by get_last_target_status(). */
391 static ptid_t target_last_wait_ptid;
392 static struct target_waitstatus target_last_waitstatus;
393
394 static void context_switch (ptid_t ptid);
395
396 void init_thread_stepping_state (struct thread_info *tss);
397
398 static const char follow_fork_mode_child[] = "child";
399 static const char follow_fork_mode_parent[] = "parent";
400
401 static const char *const follow_fork_mode_kind_names[] = {
402 follow_fork_mode_child,
403 follow_fork_mode_parent,
404 NULL
405 };
406
407 static const char *follow_fork_mode_string = follow_fork_mode_parent;
408 static void
409 show_follow_fork_mode_string (struct ui_file *file, int from_tty,
410 struct cmd_list_element *c, const char *value)
411 {
412 fprintf_filtered (file,
413 _("Debugger response to a program "
414 "call of fork or vfork is \"%s\".\n"),
415 value);
416 }
417 \f
418
419 /* Handle changes to the inferior list based on the type of fork,
420 which process is being followed, and whether the other process
421 should be detached. On entry inferior_ptid must be the ptid of
422 the fork parent. At return inferior_ptid is the ptid of the
423 followed inferior. */
424
425 static int
426 follow_fork_inferior (int follow_child, int detach_fork)
427 {
428 int has_vforked;
429 ptid_t parent_ptid, child_ptid;
430
431 has_vforked = (inferior_thread ()->pending_follow.kind
432 == TARGET_WAITKIND_VFORKED);
433 parent_ptid = inferior_ptid;
434 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
435
436 if (has_vforked
437 && !non_stop /* Non-stop always resumes both branches. */
438 && current_ui->prompt_state == PROMPT_BLOCKED
439 && !(follow_child || detach_fork || sched_multi))
440 {
441 /* The parent stays blocked inside the vfork syscall until the
442 child execs or exits. If we don't let the child run, then
443 the parent stays blocked. If we're telling the parent to run
444 in the foreground, the user will not be able to ctrl-c to get
445 back the terminal, effectively hanging the debug session. */
446 fprintf_filtered (gdb_stderr, _("\
447 Can not resume the parent process over vfork in the foreground while\n\
448 holding the child stopped. Try \"set detach-on-fork\" or \
449 \"set schedule-multiple\".\n"));
450 /* FIXME output string > 80 columns. */
451 return 1;
452 }
453
454 if (!follow_child)
455 {
456 /* Detach new forked process? */
457 if (detach_fork)
458 {
459 /* Before detaching from the child, remove all breakpoints
460 from it. If we forked, then this has already been taken
461 care of by infrun.c. If we vforked however, any
462 breakpoint inserted in the parent is visible in the
463 child, even those added while stopped in a vfork
464 catchpoint. This will remove the breakpoints from the
465 parent also, but they'll be reinserted below. */
466 if (has_vforked)
467 {
468 /* Keep breakpoints list in sync. */
469 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
470 }
471
472 if (info_verbose || debug_infrun)
473 {
474 /* Ensure that we have a process ptid. */
475 ptid_t process_ptid = pid_to_ptid (ptid_get_pid (child_ptid));
476
477 target_terminal::ours_for_output ();
478 fprintf_filtered (gdb_stdlog,
479 _("Detaching after %s from child %s.\n"),
480 has_vforked ? "vfork" : "fork",
481 target_pid_to_str (process_ptid));
482 }
483 }
484 else
485 {
486 struct inferior *parent_inf, *child_inf;
487
488 /* Add process to GDB's tables. */
489 child_inf = add_inferior (ptid_get_pid (child_ptid));
490
491 parent_inf = current_inferior ();
492 child_inf->attach_flag = parent_inf->attach_flag;
493 copy_terminal_info (child_inf, parent_inf);
494 child_inf->gdbarch = parent_inf->gdbarch;
495 copy_inferior_target_desc_info (child_inf, parent_inf);
496
497 scoped_restore_current_pspace_and_thread restore_pspace_thread;
498
499 inferior_ptid = child_ptid;
500 add_thread (inferior_ptid);
501 set_current_inferior (child_inf);
502 child_inf->symfile_flags = SYMFILE_NO_READ;
503
504 /* If this is a vfork child, then the address-space is
505 shared with the parent. */
506 if (has_vforked)
507 {
508 child_inf->pspace = parent_inf->pspace;
509 child_inf->aspace = parent_inf->aspace;
510
511 /* The parent will be frozen until the child is done
512 with the shared region. Keep track of the
513 parent. */
514 child_inf->vfork_parent = parent_inf;
515 child_inf->pending_detach = 0;
516 parent_inf->vfork_child = child_inf;
517 parent_inf->pending_detach = 0;
518 }
519 else
520 {
521 child_inf->aspace = new_address_space ();
522 child_inf->pspace = add_program_space (child_inf->aspace);
523 child_inf->removable = 1;
524 set_current_program_space (child_inf->pspace);
525 clone_program_space (child_inf->pspace, parent_inf->pspace);
526
527 /* Let the shared library layer (e.g., solib-svr4) learn
528 about this new process, relocate the cloned exec, pull
529 in shared libraries, and install the solib event
530 breakpoint. If a "cloned-VM" event was propagated
531 better throughout the core, this wouldn't be
532 required. */
533 solib_create_inferior_hook (0);
534 }
535 }
536
537 if (has_vforked)
538 {
539 struct inferior *parent_inf;
540
541 parent_inf = current_inferior ();
542
543 /* If we detached from the child, then we have to be careful
544 to not insert breakpoints in the parent until the child
545 is done with the shared memory region. However, if we're
546 staying attached to the child, then we can and should
547 insert breakpoints, so that we can debug it. A
548 subsequent child exec or exit is enough to know when does
549 the child stops using the parent's address space. */
550 parent_inf->waiting_for_vfork_done = detach_fork;
551 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
552 }
553 }
554 else
555 {
556 /* Follow the child. */
557 struct inferior *parent_inf, *child_inf;
558 struct program_space *parent_pspace;
559
560 if (info_verbose || debug_infrun)
561 {
562 target_terminal::ours_for_output ();
563 fprintf_filtered (gdb_stdlog,
564 _("Attaching after %s %s to child %s.\n"),
565 target_pid_to_str (parent_ptid),
566 has_vforked ? "vfork" : "fork",
567 target_pid_to_str (child_ptid));
568 }
569
570 /* Add the new inferior first, so that the target_detach below
571 doesn't unpush the target. */
572
573 child_inf = add_inferior (ptid_get_pid (child_ptid));
574
575 parent_inf = current_inferior ();
576 child_inf->attach_flag = parent_inf->attach_flag;
577 copy_terminal_info (child_inf, parent_inf);
578 child_inf->gdbarch = parent_inf->gdbarch;
579 copy_inferior_target_desc_info (child_inf, parent_inf);
580
581 parent_pspace = parent_inf->pspace;
582
583 /* If we're vforking, we want to hold on to the parent until the
584 child exits or execs. At child exec or exit time we can
585 remove the old breakpoints from the parent and detach or
586 resume debugging it. Otherwise, detach the parent now; we'll
587 want to reuse it's program/address spaces, but we can't set
588 them to the child before removing breakpoints from the
589 parent, otherwise, the breakpoints module could decide to
590 remove breakpoints from the wrong process (since they'd be
591 assigned to the same address space). */
592
593 if (has_vforked)
594 {
595 gdb_assert (child_inf->vfork_parent == NULL);
596 gdb_assert (parent_inf->vfork_child == NULL);
597 child_inf->vfork_parent = parent_inf;
598 child_inf->pending_detach = 0;
599 parent_inf->vfork_child = child_inf;
600 parent_inf->pending_detach = detach_fork;
601 parent_inf->waiting_for_vfork_done = 0;
602 }
603 else if (detach_fork)
604 {
605 if (info_verbose || debug_infrun)
606 {
607 /* Ensure that we have a process ptid. */
608 ptid_t process_ptid = pid_to_ptid (ptid_get_pid (child_ptid));
609
610 target_terminal::ours_for_output ();
611 fprintf_filtered (gdb_stdlog,
612 _("Detaching after fork from "
613 "child %s.\n"),
614 target_pid_to_str (process_ptid));
615 }
616
617 target_detach (NULL, 0);
618 }
619
620 /* Note that the detach above makes PARENT_INF dangling. */
621
622 /* Add the child thread to the appropriate lists, and switch to
623 this new thread, before cloning the program space, and
624 informing the solib layer about this new process. */
625
626 inferior_ptid = child_ptid;
627 add_thread (inferior_ptid);
628 set_current_inferior (child_inf);
629
630 /* If this is a vfork child, then the address-space is shared
631 with the parent. If we detached from the parent, then we can
632 reuse the parent's program/address spaces. */
633 if (has_vforked || detach_fork)
634 {
635 child_inf->pspace = parent_pspace;
636 child_inf->aspace = child_inf->pspace->aspace;
637 }
638 else
639 {
640 child_inf->aspace = new_address_space ();
641 child_inf->pspace = add_program_space (child_inf->aspace);
642 child_inf->removable = 1;
643 child_inf->symfile_flags = SYMFILE_NO_READ;
644 set_current_program_space (child_inf->pspace);
645 clone_program_space (child_inf->pspace, parent_pspace);
646
647 /* Let the shared library layer (e.g., solib-svr4) learn
648 about this new process, relocate the cloned exec, pull in
649 shared libraries, and install the solib event breakpoint.
650 If a "cloned-VM" event was propagated better throughout
651 the core, this wouldn't be required. */
652 solib_create_inferior_hook (0);
653 }
654 }
655
656 return target_follow_fork (follow_child, detach_fork);
657 }
658
659 /* Tell the target to follow the fork we're stopped at. Returns true
660 if the inferior should be resumed; false, if the target for some
661 reason decided it's best not to resume. */
662
663 static int
664 follow_fork (void)
665 {
666 int follow_child = (follow_fork_mode_string == follow_fork_mode_child);
667 int should_resume = 1;
668 struct thread_info *tp;
669
670 /* Copy user stepping state to the new inferior thread. FIXME: the
671 followed fork child thread should have a copy of most of the
672 parent thread structure's run control related fields, not just these.
673 Initialized to avoid "may be used uninitialized" warnings from gcc. */
674 struct breakpoint *step_resume_breakpoint = NULL;
675 struct breakpoint *exception_resume_breakpoint = NULL;
676 CORE_ADDR step_range_start = 0;
677 CORE_ADDR step_range_end = 0;
678 struct frame_id step_frame_id = { 0 };
679 struct thread_fsm *thread_fsm = NULL;
680
681 if (!non_stop)
682 {
683 ptid_t wait_ptid;
684 struct target_waitstatus wait_status;
685
686 /* Get the last target status returned by target_wait(). */
687 get_last_target_status (&wait_ptid, &wait_status);
688
689 /* If not stopped at a fork event, then there's nothing else to
690 do. */
691 if (wait_status.kind != TARGET_WAITKIND_FORKED
692 && wait_status.kind != TARGET_WAITKIND_VFORKED)
693 return 1;
694
695 /* Check if we switched over from WAIT_PTID, since the event was
696 reported. */
697 if (!ptid_equal (wait_ptid, minus_one_ptid)
698 && !ptid_equal (inferior_ptid, wait_ptid))
699 {
700 /* We did. Switch back to WAIT_PTID thread, to tell the
701 target to follow it (in either direction). We'll
702 afterwards refuse to resume, and inform the user what
703 happened. */
704 switch_to_thread (wait_ptid);
705 should_resume = 0;
706 }
707 }
708
709 tp = inferior_thread ();
710
711 /* If there were any forks/vforks that were caught and are now to be
712 followed, then do so now. */
713 switch (tp->pending_follow.kind)
714 {
715 case TARGET_WAITKIND_FORKED:
716 case TARGET_WAITKIND_VFORKED:
717 {
718 ptid_t parent, child;
719
720 /* If the user did a next/step, etc, over a fork call,
721 preserve the stepping state in the fork child. */
722 if (follow_child && should_resume)
723 {
724 step_resume_breakpoint = clone_momentary_breakpoint
725 (tp->control.step_resume_breakpoint);
726 step_range_start = tp->control.step_range_start;
727 step_range_end = tp->control.step_range_end;
728 step_frame_id = tp->control.step_frame_id;
729 exception_resume_breakpoint
730 = clone_momentary_breakpoint (tp->control.exception_resume_breakpoint);
731 thread_fsm = tp->thread_fsm;
732
733 /* For now, delete the parent's sr breakpoint, otherwise,
734 parent/child sr breakpoints are considered duplicates,
735 and the child version will not be installed. Remove
736 this when the breakpoints module becomes aware of
737 inferiors and address spaces. */
738 delete_step_resume_breakpoint (tp);
739 tp->control.step_range_start = 0;
740 tp->control.step_range_end = 0;
741 tp->control.step_frame_id = null_frame_id;
742 delete_exception_resume_breakpoint (tp);
743 tp->thread_fsm = NULL;
744 }
745
746 parent = inferior_ptid;
747 child = tp->pending_follow.value.related_pid;
748
749 /* Set up inferior(s) as specified by the caller, and tell the
750 target to do whatever is necessary to follow either parent
751 or child. */
752 if (follow_fork_inferior (follow_child, detach_fork))
753 {
754 /* Target refused to follow, or there's some other reason
755 we shouldn't resume. */
756 should_resume = 0;
757 }
758 else
759 {
760 /* This pending follow fork event is now handled, one way
761 or another. The previous selected thread may be gone
762 from the lists by now, but if it is still around, need
763 to clear the pending follow request. */
764 tp = find_thread_ptid (parent);
765 if (tp)
766 tp->pending_follow.kind = TARGET_WAITKIND_SPURIOUS;
767
768 /* This makes sure we don't try to apply the "Switched
769 over from WAIT_PID" logic above. */
770 nullify_last_target_wait_ptid ();
771
772 /* If we followed the child, switch to it... */
773 if (follow_child)
774 {
775 switch_to_thread (child);
776
777 /* ... and preserve the stepping state, in case the
778 user was stepping over the fork call. */
779 if (should_resume)
780 {
781 tp = inferior_thread ();
782 tp->control.step_resume_breakpoint
783 = step_resume_breakpoint;
784 tp->control.step_range_start = step_range_start;
785 tp->control.step_range_end = step_range_end;
786 tp->control.step_frame_id = step_frame_id;
787 tp->control.exception_resume_breakpoint
788 = exception_resume_breakpoint;
789 tp->thread_fsm = thread_fsm;
790 }
791 else
792 {
793 /* If we get here, it was because we're trying to
794 resume from a fork catchpoint, but, the user
795 has switched threads away from the thread that
796 forked. In that case, the resume command
797 issued is most likely not applicable to the
798 child, so just warn, and refuse to resume. */
799 warning (_("Not resuming: switched threads "
800 "before following fork child."));
801 }
802
803 /* Reset breakpoints in the child as appropriate. */
804 follow_inferior_reset_breakpoints ();
805 }
806 else
807 switch_to_thread (parent);
808 }
809 }
810 break;
811 case TARGET_WAITKIND_SPURIOUS:
812 /* Nothing to follow. */
813 break;
814 default:
815 internal_error (__FILE__, __LINE__,
816 "Unexpected pending_follow.kind %d\n",
817 tp->pending_follow.kind);
818 break;
819 }
820
821 return should_resume;
822 }
823
824 static void
825 follow_inferior_reset_breakpoints (void)
826 {
827 struct thread_info *tp = inferior_thread ();
828
829 /* Was there a step_resume breakpoint? (There was if the user
830 did a "next" at the fork() call.) If so, explicitly reset its
831 thread number. Cloned step_resume breakpoints are disabled on
832 creation, so enable it here now that it is associated with the
833 correct thread.
834
835 step_resumes are a form of bp that are made to be per-thread.
836 Since we created the step_resume bp when the parent process
837 was being debugged, and now are switching to the child process,
838 from the breakpoint package's viewpoint, that's a switch of
839 "threads". We must update the bp's notion of which thread
840 it is for, or it'll be ignored when it triggers. */
841
842 if (tp->control.step_resume_breakpoint)
843 {
844 breakpoint_re_set_thread (tp->control.step_resume_breakpoint);
845 tp->control.step_resume_breakpoint->loc->enabled = 1;
846 }
847
848 /* Treat exception_resume breakpoints like step_resume breakpoints. */
849 if (tp->control.exception_resume_breakpoint)
850 {
851 breakpoint_re_set_thread (tp->control.exception_resume_breakpoint);
852 tp->control.exception_resume_breakpoint->loc->enabled = 1;
853 }
854
855 /* Reinsert all breakpoints in the child. The user may have set
856 breakpoints after catching the fork, in which case those
857 were never set in the child, but only in the parent. This makes
858 sure the inserted breakpoints match the breakpoint list. */
859
860 breakpoint_re_set ();
861 insert_breakpoints ();
862 }
863
864 /* The child has exited or execed: resume threads of the parent the
865 user wanted to be executing. */
866
867 static int
868 proceed_after_vfork_done (struct thread_info *thread,
869 void *arg)
870 {
871 int pid = * (int *) arg;
872
873 if (ptid_get_pid (thread->ptid) == pid
874 && is_running (thread->ptid)
875 && !is_executing (thread->ptid)
876 && !thread->stop_requested
877 && thread->suspend.stop_signal == GDB_SIGNAL_0)
878 {
879 if (debug_infrun)
880 fprintf_unfiltered (gdb_stdlog,
881 "infrun: resuming vfork parent thread %s\n",
882 target_pid_to_str (thread->ptid));
883
884 switch_to_thread (thread->ptid);
885 clear_proceed_status (0);
886 proceed ((CORE_ADDR) -1, GDB_SIGNAL_DEFAULT);
887 }
888
889 return 0;
890 }
891
892 /* Save/restore inferior_ptid, current program space and current
893 inferior. Only use this if the current context points at an exited
894 inferior (and therefore there's no current thread to save). */
895 class scoped_restore_exited_inferior
896 {
897 public:
898 scoped_restore_exited_inferior ()
899 : m_saved_ptid (&inferior_ptid)
900 {}
901
902 private:
903 scoped_restore_tmpl<ptid_t> m_saved_ptid;
904 scoped_restore_current_program_space m_pspace;
905 scoped_restore_current_inferior m_inferior;
906 };
907
908 /* Called whenever we notice an exec or exit event, to handle
909 detaching or resuming a vfork parent. */
910
911 static void
912 handle_vfork_child_exec_or_exit (int exec)
913 {
914 struct inferior *inf = current_inferior ();
915
916 if (inf->vfork_parent)
917 {
918 int resume_parent = -1;
919
920 /* This exec or exit marks the end of the shared memory region
921 between the parent and the child. If the user wanted to
922 detach from the parent, now is the time. */
923
924 if (inf->vfork_parent->pending_detach)
925 {
926 struct thread_info *tp;
927 struct program_space *pspace;
928 struct address_space *aspace;
929
930 /* follow-fork child, detach-on-fork on. */
931
932 inf->vfork_parent->pending_detach = 0;
933
934 gdb::optional<scoped_restore_exited_inferior>
935 maybe_restore_inferior;
936 gdb::optional<scoped_restore_current_pspace_and_thread>
937 maybe_restore_thread;
938
939 /* If we're handling a child exit, then inferior_ptid points
940 at the inferior's pid, not to a thread. */
941 if (!exec)
942 maybe_restore_inferior.emplace ();
943 else
944 maybe_restore_thread.emplace ();
945
946 /* We're letting loose of the parent. */
947 tp = any_live_thread_of_process (inf->vfork_parent->pid);
948 switch_to_thread (tp->ptid);
949
950 /* We're about to detach from the parent, which implicitly
951 removes breakpoints from its address space. There's a
952 catch here: we want to reuse the spaces for the child,
953 but, parent/child are still sharing the pspace at this
954 point, although the exec in reality makes the kernel give
955 the child a fresh set of new pages. The problem here is
956 that the breakpoints module being unaware of this, would
957 likely chose the child process to write to the parent
958 address space. Swapping the child temporarily away from
959 the spaces has the desired effect. Yes, this is "sort
960 of" a hack. */
961
962 pspace = inf->pspace;
963 aspace = inf->aspace;
964 inf->aspace = NULL;
965 inf->pspace = NULL;
966
967 if (debug_infrun || info_verbose)
968 {
969 target_terminal::ours_for_output ();
970
971 if (exec)
972 {
973 fprintf_filtered (gdb_stdlog,
974 _("Detaching vfork parent process "
975 "%d after child exec.\n"),
976 inf->vfork_parent->pid);
977 }
978 else
979 {
980 fprintf_filtered (gdb_stdlog,
981 _("Detaching vfork parent process "
982 "%d after child exit.\n"),
983 inf->vfork_parent->pid);
984 }
985 }
986
987 target_detach (NULL, 0);
988
989 /* Put it back. */
990 inf->pspace = pspace;
991 inf->aspace = aspace;
992 }
993 else if (exec)
994 {
995 /* We're staying attached to the parent, so, really give the
996 child a new address space. */
997 inf->pspace = add_program_space (maybe_new_address_space ());
998 inf->aspace = inf->pspace->aspace;
999 inf->removable = 1;
1000 set_current_program_space (inf->pspace);
1001
1002 resume_parent = inf->vfork_parent->pid;
1003
1004 /* Break the bonds. */
1005 inf->vfork_parent->vfork_child = NULL;
1006 }
1007 else
1008 {
1009 struct program_space *pspace;
1010
1011 /* If this is a vfork child exiting, then the pspace and
1012 aspaces were shared with the parent. Since we're
1013 reporting the process exit, we'll be mourning all that is
1014 found in the address space, and switching to null_ptid,
1015 preparing to start a new inferior. But, since we don't
1016 want to clobber the parent's address/program spaces, we
1017 go ahead and create a new one for this exiting
1018 inferior. */
1019
1020 /* Switch to null_ptid while running clone_program_space, so
1021 that clone_program_space doesn't want to read the
1022 selected frame of a dead process. */
1023 scoped_restore restore_ptid
1024 = make_scoped_restore (&inferior_ptid, null_ptid);
1025
1026 /* This inferior is dead, so avoid giving the breakpoints
1027 module the option to write through to it (cloning a
1028 program space resets breakpoints). */
1029 inf->aspace = NULL;
1030 inf->pspace = NULL;
1031 pspace = add_program_space (maybe_new_address_space ());
1032 set_current_program_space (pspace);
1033 inf->removable = 1;
1034 inf->symfile_flags = SYMFILE_NO_READ;
1035 clone_program_space (pspace, inf->vfork_parent->pspace);
1036 inf->pspace = pspace;
1037 inf->aspace = pspace->aspace;
1038
1039 resume_parent = inf->vfork_parent->pid;
1040 /* Break the bonds. */
1041 inf->vfork_parent->vfork_child = NULL;
1042 }
1043
1044 inf->vfork_parent = NULL;
1045
1046 gdb_assert (current_program_space == inf->pspace);
1047
1048 if (non_stop && resume_parent != -1)
1049 {
1050 /* If the user wanted the parent to be running, let it go
1051 free now. */
1052 scoped_restore_current_thread restore_thread;
1053
1054 if (debug_infrun)
1055 fprintf_unfiltered (gdb_stdlog,
1056 "infrun: resuming vfork parent process %d\n",
1057 resume_parent);
1058
1059 iterate_over_threads (proceed_after_vfork_done, &resume_parent);
1060 }
1061 }
1062 }
1063
1064 /* Enum strings for "set|show follow-exec-mode". */
1065
1066 static const char follow_exec_mode_new[] = "new";
1067 static const char follow_exec_mode_same[] = "same";
1068 static const char *const follow_exec_mode_names[] =
1069 {
1070 follow_exec_mode_new,
1071 follow_exec_mode_same,
1072 NULL,
1073 };
1074
1075 static const char *follow_exec_mode_string = follow_exec_mode_same;
1076 static void
1077 show_follow_exec_mode_string (struct ui_file *file, int from_tty,
1078 struct cmd_list_element *c, const char *value)
1079 {
1080 fprintf_filtered (file, _("Follow exec mode is \"%s\".\n"), value);
1081 }
1082
1083 /* EXEC_FILE_TARGET is assumed to be non-NULL. */
1084
1085 static void
1086 follow_exec (ptid_t ptid, char *exec_file_target)
1087 {
1088 struct thread_info *th, *tmp;
1089 struct inferior *inf = current_inferior ();
1090 int pid = ptid_get_pid (ptid);
1091 ptid_t process_ptid;
1092 char *exec_file_host;
1093 struct cleanup *old_chain;
1094
1095 /* This is an exec event that we actually wish to pay attention to.
1096 Refresh our symbol table to the newly exec'd program, remove any
1097 momentary bp's, etc.
1098
1099 If there are breakpoints, they aren't really inserted now,
1100 since the exec() transformed our inferior into a fresh set
1101 of instructions.
1102
1103 We want to preserve symbolic breakpoints on the list, since
1104 we have hopes that they can be reset after the new a.out's
1105 symbol table is read.
1106
1107 However, any "raw" breakpoints must be removed from the list
1108 (e.g., the solib bp's), since their address is probably invalid
1109 now.
1110
1111 And, we DON'T want to call delete_breakpoints() here, since
1112 that may write the bp's "shadow contents" (the instruction
1113 value that was overwritten witha TRAP instruction). Since
1114 we now have a new a.out, those shadow contents aren't valid. */
1115
1116 mark_breakpoints_out ();
1117
1118 /* The target reports the exec event to the main thread, even if
1119 some other thread does the exec, and even if the main thread was
1120 stopped or already gone. We may still have non-leader threads of
1121 the process on our list. E.g., on targets that don't have thread
1122 exit events (like remote); or on native Linux in non-stop mode if
1123 there were only two threads in the inferior and the non-leader
1124 one is the one that execs (and nothing forces an update of the
1125 thread list up to here). When debugging remotely, it's best to
1126 avoid extra traffic, when possible, so avoid syncing the thread
1127 list with the target, and instead go ahead and delete all threads
1128 of the process but one that reported the event. Note this must
1129 be done before calling update_breakpoints_after_exec, as
1130 otherwise clearing the threads' resources would reference stale
1131 thread breakpoints -- it may have been one of these threads that
1132 stepped across the exec. We could just clear their stepping
1133 states, but as long as we're iterating, might as well delete
1134 them. Deleting them now rather than at the next user-visible
1135 stop provides a nicer sequence of events for user and MI
1136 notifications. */
1137 ALL_THREADS_SAFE (th, tmp)
1138 if (ptid_get_pid (th->ptid) == pid && !ptid_equal (th->ptid, ptid))
1139 delete_thread (th->ptid);
1140
1141 /* We also need to clear any left over stale state for the
1142 leader/event thread. E.g., if there was any step-resume
1143 breakpoint or similar, it's gone now. We cannot truly
1144 step-to-next statement through an exec(). */
1145 th = inferior_thread ();
1146 th->control.step_resume_breakpoint = NULL;
1147 th->control.exception_resume_breakpoint = NULL;
1148 th->control.single_step_breakpoints = NULL;
1149 th->control.step_range_start = 0;
1150 th->control.step_range_end = 0;
1151
1152 /* The user may have had the main thread held stopped in the
1153 previous image (e.g., schedlock on, or non-stop). Release
1154 it now. */
1155 th->stop_requested = 0;
1156
1157 update_breakpoints_after_exec ();
1158
1159 /* What is this a.out's name? */
1160 process_ptid = pid_to_ptid (pid);
1161 printf_unfiltered (_("%s is executing new program: %s\n"),
1162 target_pid_to_str (process_ptid),
1163 exec_file_target);
1164
1165 /* We've followed the inferior through an exec. Therefore, the
1166 inferior has essentially been killed & reborn. */
1167
1168 gdb_flush (gdb_stdout);
1169
1170 breakpoint_init_inferior (inf_execd);
1171
1172 exec_file_host = exec_file_find (exec_file_target, NULL);
1173 old_chain = make_cleanup (xfree, exec_file_host);
1174
1175 /* If we were unable to map the executable target pathname onto a host
1176 pathname, tell the user that. Otherwise GDB's subsequent behavior
1177 is confusing. Maybe it would even be better to stop at this point
1178 so that the user can specify a file manually before continuing. */
1179 if (exec_file_host == NULL)
1180 warning (_("Could not load symbols for executable %s.\n"
1181 "Do you need \"set sysroot\"?"),
1182 exec_file_target);
1183
1184 /* Reset the shared library package. This ensures that we get a
1185 shlib event when the child reaches "_start", at which point the
1186 dld will have had a chance to initialize the child. */
1187 /* Also, loading a symbol file below may trigger symbol lookups, and
1188 we don't want those to be satisfied by the libraries of the
1189 previous incarnation of this process. */
1190 no_shared_libraries (NULL, 0);
1191
1192 if (follow_exec_mode_string == follow_exec_mode_new)
1193 {
1194 /* The user wants to keep the old inferior and program spaces
1195 around. Create a new fresh one, and switch to it. */
1196
1197 /* Do exit processing for the original inferior before adding
1198 the new inferior so we don't have two active inferiors with
1199 the same ptid, which can confuse find_inferior_ptid. */
1200 exit_inferior_num_silent (current_inferior ()->num);
1201
1202 inf = add_inferior_with_spaces ();
1203 inf->pid = pid;
1204 target_follow_exec (inf, exec_file_target);
1205
1206 set_current_inferior (inf);
1207 set_current_program_space (inf->pspace);
1208 }
1209 else
1210 {
1211 /* The old description may no longer be fit for the new image.
1212 E.g, a 64-bit process exec'ed a 32-bit process. Clear the
1213 old description; we'll read a new one below. No need to do
1214 this on "follow-exec-mode new", as the old inferior stays
1215 around (its description is later cleared/refetched on
1216 restart). */
1217 target_clear_description ();
1218 }
1219
1220 gdb_assert (current_program_space == inf->pspace);
1221
1222 /* Attempt to open the exec file. SYMFILE_DEFER_BP_RESET is used
1223 because the proper displacement for a PIE (Position Independent
1224 Executable) main symbol file will only be computed by
1225 solib_create_inferior_hook below. breakpoint_re_set would fail
1226 to insert the breakpoints with the zero displacement. */
1227 try_open_exec_file (exec_file_host, inf, SYMFILE_DEFER_BP_RESET);
1228
1229 do_cleanups (old_chain);
1230
1231 /* If the target can specify a description, read it. Must do this
1232 after flipping to the new executable (because the target supplied
1233 description must be compatible with the executable's
1234 architecture, and the old executable may e.g., be 32-bit, while
1235 the new one 64-bit), and before anything involving memory or
1236 registers. */
1237 target_find_description ();
1238
1239 /* The add_thread call ends up reading registers, so do it after updating the
1240 target description. */
1241 if (follow_exec_mode_string == follow_exec_mode_new)
1242 add_thread (ptid);
1243
1244 solib_create_inferior_hook (0);
1245
1246 jit_inferior_created_hook ();
1247
1248 breakpoint_re_set ();
1249
1250 /* Reinsert all breakpoints. (Those which were symbolic have
1251 been reset to the proper address in the new a.out, thanks
1252 to symbol_file_command...). */
1253 insert_breakpoints ();
1254
1255 /* The next resume of this inferior should bring it to the shlib
1256 startup breakpoints. (If the user had also set bp's on
1257 "main" from the old (parent) process, then they'll auto-
1258 matically get reset there in the new process.). */
1259 }
1260
1261 /* The queue of threads that need to do a step-over operation to get
1262 past e.g., a breakpoint. What technique is used to step over the
1263 breakpoint/watchpoint does not matter -- all threads end up in the
1264 same queue, to maintain rough temporal order of execution, in order
1265 to avoid starvation, otherwise, we could e.g., find ourselves
1266 constantly stepping the same couple threads past their breakpoints
1267 over and over, if the single-step finish fast enough. */
1268 struct thread_info *step_over_queue_head;
1269
1270 /* Bit flags indicating what the thread needs to step over. */
1271
1272 enum step_over_what_flag
1273 {
1274 /* Step over a breakpoint. */
1275 STEP_OVER_BREAKPOINT = 1,
1276
1277 /* Step past a non-continuable watchpoint, in order to let the
1278 instruction execute so we can evaluate the watchpoint
1279 expression. */
1280 STEP_OVER_WATCHPOINT = 2
1281 };
1282 DEF_ENUM_FLAGS_TYPE (enum step_over_what_flag, step_over_what);
1283
1284 /* Info about an instruction that is being stepped over. */
1285
1286 struct step_over_info
1287 {
1288 /* If we're stepping past a breakpoint, this is the address space
1289 and address of the instruction the breakpoint is set at. We'll
1290 skip inserting all breakpoints here. Valid iff ASPACE is
1291 non-NULL. */
1292 const address_space *aspace;
1293 CORE_ADDR address;
1294
1295 /* The instruction being stepped over triggers a nonsteppable
1296 watchpoint. If true, we'll skip inserting watchpoints. */
1297 int nonsteppable_watchpoint_p;
1298
1299 /* The thread's global number. */
1300 int thread;
1301 };
1302
1303 /* The step-over info of the location that is being stepped over.
1304
1305 Note that with async/breakpoint always-inserted mode, a user might
1306 set a new breakpoint/watchpoint/etc. exactly while a breakpoint is
1307 being stepped over. As setting a new breakpoint inserts all
1308 breakpoints, we need to make sure the breakpoint being stepped over
1309 isn't inserted then. We do that by only clearing the step-over
1310 info when the step-over is actually finished (or aborted).
1311
1312 Presently GDB can only step over one breakpoint at any given time.
1313 Given threads that can't run code in the same address space as the
1314 breakpoint's can't really miss the breakpoint, GDB could be taught
1315 to step-over at most one breakpoint per address space (so this info
1316 could move to the address space object if/when GDB is extended).
1317 The set of breakpoints being stepped over will normally be much
1318 smaller than the set of all breakpoints, so a flag in the
1319 breakpoint location structure would be wasteful. A separate list
1320 also saves complexity and run-time, as otherwise we'd have to go
1321 through all breakpoint locations clearing their flag whenever we
1322 start a new sequence. Similar considerations weigh against storing
1323 this info in the thread object. Plus, not all step overs actually
1324 have breakpoint locations -- e.g., stepping past a single-step
1325 breakpoint, or stepping to complete a non-continuable
1326 watchpoint. */
1327 static struct step_over_info step_over_info;
1328
1329 /* Record the address of the breakpoint/instruction we're currently
1330 stepping over.
1331 N.B. We record the aspace and address now, instead of say just the thread,
1332 because when we need the info later the thread may be running. */
1333
1334 static void
1335 set_step_over_info (const address_space *aspace, CORE_ADDR address,
1336 int nonsteppable_watchpoint_p,
1337 int thread)
1338 {
1339 step_over_info.aspace = aspace;
1340 step_over_info.address = address;
1341 step_over_info.nonsteppable_watchpoint_p = nonsteppable_watchpoint_p;
1342 step_over_info.thread = thread;
1343 }
1344
1345 /* Called when we're not longer stepping over a breakpoint / an
1346 instruction, so all breakpoints are free to be (re)inserted. */
1347
1348 static void
1349 clear_step_over_info (void)
1350 {
1351 if (debug_infrun)
1352 fprintf_unfiltered (gdb_stdlog,
1353 "infrun: clear_step_over_info\n");
1354 step_over_info.aspace = NULL;
1355 step_over_info.address = 0;
1356 step_over_info.nonsteppable_watchpoint_p = 0;
1357 step_over_info.thread = -1;
1358 }
1359
1360 /* See infrun.h. */
1361
1362 int
1363 stepping_past_instruction_at (struct address_space *aspace,
1364 CORE_ADDR address)
1365 {
1366 return (step_over_info.aspace != NULL
1367 && breakpoint_address_match (aspace, address,
1368 step_over_info.aspace,
1369 step_over_info.address));
1370 }
1371
1372 /* See infrun.h. */
1373
1374 int
1375 thread_is_stepping_over_breakpoint (int thread)
1376 {
1377 return (step_over_info.thread != -1
1378 && thread == step_over_info.thread);
1379 }
1380
1381 /* See infrun.h. */
1382
1383 int
1384 stepping_past_nonsteppable_watchpoint (void)
1385 {
1386 return step_over_info.nonsteppable_watchpoint_p;
1387 }
1388
1389 /* Returns true if step-over info is valid. */
1390
1391 static int
1392 step_over_info_valid_p (void)
1393 {
1394 return (step_over_info.aspace != NULL
1395 || stepping_past_nonsteppable_watchpoint ());
1396 }
1397
1398 \f
1399 /* Displaced stepping. */
1400
1401 /* In non-stop debugging mode, we must take special care to manage
1402 breakpoints properly; in particular, the traditional strategy for
1403 stepping a thread past a breakpoint it has hit is unsuitable.
1404 'Displaced stepping' is a tactic for stepping one thread past a
1405 breakpoint it has hit while ensuring that other threads running
1406 concurrently will hit the breakpoint as they should.
1407
1408 The traditional way to step a thread T off a breakpoint in a
1409 multi-threaded program in all-stop mode is as follows:
1410
1411 a0) Initially, all threads are stopped, and breakpoints are not
1412 inserted.
1413 a1) We single-step T, leaving breakpoints uninserted.
1414 a2) We insert breakpoints, and resume all threads.
1415
1416 In non-stop debugging, however, this strategy is unsuitable: we
1417 don't want to have to stop all threads in the system in order to
1418 continue or step T past a breakpoint. Instead, we use displaced
1419 stepping:
1420
1421 n0) Initially, T is stopped, other threads are running, and
1422 breakpoints are inserted.
1423 n1) We copy the instruction "under" the breakpoint to a separate
1424 location, outside the main code stream, making any adjustments
1425 to the instruction, register, and memory state as directed by
1426 T's architecture.
1427 n2) We single-step T over the instruction at its new location.
1428 n3) We adjust the resulting register and memory state as directed
1429 by T's architecture. This includes resetting T's PC to point
1430 back into the main instruction stream.
1431 n4) We resume T.
1432
1433 This approach depends on the following gdbarch methods:
1434
1435 - gdbarch_max_insn_length and gdbarch_displaced_step_location
1436 indicate where to copy the instruction, and how much space must
1437 be reserved there. We use these in step n1.
1438
1439 - gdbarch_displaced_step_copy_insn copies a instruction to a new
1440 address, and makes any necessary adjustments to the instruction,
1441 register contents, and memory. We use this in step n1.
1442
1443 - gdbarch_displaced_step_fixup adjusts registers and memory after
1444 we have successfuly single-stepped the instruction, to yield the
1445 same effect the instruction would have had if we had executed it
1446 at its original address. We use this in step n3.
1447
1448 The gdbarch_displaced_step_copy_insn and
1449 gdbarch_displaced_step_fixup functions must be written so that
1450 copying an instruction with gdbarch_displaced_step_copy_insn,
1451 single-stepping across the copied instruction, and then applying
1452 gdbarch_displaced_insn_fixup should have the same effects on the
1453 thread's memory and registers as stepping the instruction in place
1454 would have. Exactly which responsibilities fall to the copy and
1455 which fall to the fixup is up to the author of those functions.
1456
1457 See the comments in gdbarch.sh for details.
1458
1459 Note that displaced stepping and software single-step cannot
1460 currently be used in combination, although with some care I think
1461 they could be made to. Software single-step works by placing
1462 breakpoints on all possible subsequent instructions; if the
1463 displaced instruction is a PC-relative jump, those breakpoints
1464 could fall in very strange places --- on pages that aren't
1465 executable, or at addresses that are not proper instruction
1466 boundaries. (We do generally let other threads run while we wait
1467 to hit the software single-step breakpoint, and they might
1468 encounter such a corrupted instruction.) One way to work around
1469 this would be to have gdbarch_displaced_step_copy_insn fully
1470 simulate the effect of PC-relative instructions (and return NULL)
1471 on architectures that use software single-stepping.
1472
1473 In non-stop mode, we can have independent and simultaneous step
1474 requests, so more than one thread may need to simultaneously step
1475 over a breakpoint. The current implementation assumes there is
1476 only one scratch space per process. In this case, we have to
1477 serialize access to the scratch space. If thread A wants to step
1478 over a breakpoint, but we are currently waiting for some other
1479 thread to complete a displaced step, we leave thread A stopped and
1480 place it in the displaced_step_request_queue. Whenever a displaced
1481 step finishes, we pick the next thread in the queue and start a new
1482 displaced step operation on it. See displaced_step_prepare and
1483 displaced_step_fixup for details. */
1484
1485 /* Default destructor for displaced_step_closure. */
1486
1487 displaced_step_closure::~displaced_step_closure () = default;
1488
1489 /* Per-inferior displaced stepping state. */
1490 struct displaced_step_inferior_state
1491 {
1492 /* Pointer to next in linked list. */
1493 struct displaced_step_inferior_state *next;
1494
1495 /* The process this displaced step state refers to. */
1496 int pid;
1497
1498 /* True if preparing a displaced step ever failed. If so, we won't
1499 try displaced stepping for this inferior again. */
1500 int failed_before;
1501
1502 /* If this is not null_ptid, this is the thread carrying out a
1503 displaced single-step in process PID. This thread's state will
1504 require fixing up once it has completed its step. */
1505 ptid_t step_ptid;
1506
1507 /* The architecture the thread had when we stepped it. */
1508 struct gdbarch *step_gdbarch;
1509
1510 /* The closure provided gdbarch_displaced_step_copy_insn, to be used
1511 for post-step cleanup. */
1512 struct displaced_step_closure *step_closure;
1513
1514 /* The address of the original instruction, and the copy we
1515 made. */
1516 CORE_ADDR step_original, step_copy;
1517
1518 /* Saved contents of copy area. */
1519 gdb_byte *step_saved_copy;
1520 };
1521
1522 /* The list of states of processes involved in displaced stepping
1523 presently. */
1524 static struct displaced_step_inferior_state *displaced_step_inferior_states;
1525
1526 /* Get the displaced stepping state of process PID. */
1527
1528 static struct displaced_step_inferior_state *
1529 get_displaced_stepping_state (int pid)
1530 {
1531 struct displaced_step_inferior_state *state;
1532
1533 for (state = displaced_step_inferior_states;
1534 state != NULL;
1535 state = state->next)
1536 if (state->pid == pid)
1537 return state;
1538
1539 return NULL;
1540 }
1541
1542 /* Returns true if any inferior has a thread doing a displaced
1543 step. */
1544
1545 static int
1546 displaced_step_in_progress_any_inferior (void)
1547 {
1548 struct displaced_step_inferior_state *state;
1549
1550 for (state = displaced_step_inferior_states;
1551 state != NULL;
1552 state = state->next)
1553 if (!ptid_equal (state->step_ptid, null_ptid))
1554 return 1;
1555
1556 return 0;
1557 }
1558
1559 /* Return true if thread represented by PTID is doing a displaced
1560 step. */
1561
1562 static int
1563 displaced_step_in_progress_thread (ptid_t ptid)
1564 {
1565 struct displaced_step_inferior_state *displaced;
1566
1567 gdb_assert (!ptid_equal (ptid, null_ptid));
1568
1569 displaced = get_displaced_stepping_state (ptid_get_pid (ptid));
1570
1571 return (displaced != NULL && ptid_equal (displaced->step_ptid, ptid));
1572 }
1573
1574 /* Return true if process PID has a thread doing a displaced step. */
1575
1576 static int
1577 displaced_step_in_progress (int pid)
1578 {
1579 struct displaced_step_inferior_state *displaced;
1580
1581 displaced = get_displaced_stepping_state (pid);
1582 if (displaced != NULL && !ptid_equal (displaced->step_ptid, null_ptid))
1583 return 1;
1584
1585 return 0;
1586 }
1587
1588 /* Add a new displaced stepping state for process PID to the displaced
1589 stepping state list, or return a pointer to an already existing
1590 entry, if it already exists. Never returns NULL. */
1591
1592 static struct displaced_step_inferior_state *
1593 add_displaced_stepping_state (int pid)
1594 {
1595 struct displaced_step_inferior_state *state;
1596
1597 for (state = displaced_step_inferior_states;
1598 state != NULL;
1599 state = state->next)
1600 if (state->pid == pid)
1601 return state;
1602
1603 state = XCNEW (struct displaced_step_inferior_state);
1604 state->pid = pid;
1605 state->next = displaced_step_inferior_states;
1606 displaced_step_inferior_states = state;
1607
1608 return state;
1609 }
1610
1611 /* If inferior is in displaced stepping, and ADDR equals to starting address
1612 of copy area, return corresponding displaced_step_closure. Otherwise,
1613 return NULL. */
1614
1615 struct displaced_step_closure*
1616 get_displaced_step_closure_by_addr (CORE_ADDR addr)
1617 {
1618 struct displaced_step_inferior_state *displaced
1619 = get_displaced_stepping_state (ptid_get_pid (inferior_ptid));
1620
1621 /* If checking the mode of displaced instruction in copy area. */
1622 if (displaced && !ptid_equal (displaced->step_ptid, null_ptid)
1623 && (displaced->step_copy == addr))
1624 return displaced->step_closure;
1625
1626 return NULL;
1627 }
1628
1629 /* Remove the displaced stepping state of process PID. */
1630
1631 static void
1632 remove_displaced_stepping_state (int pid)
1633 {
1634 struct displaced_step_inferior_state *it, **prev_next_p;
1635
1636 gdb_assert (pid != 0);
1637
1638 it = displaced_step_inferior_states;
1639 prev_next_p = &displaced_step_inferior_states;
1640 while (it)
1641 {
1642 if (it->pid == pid)
1643 {
1644 *prev_next_p = it->next;
1645 xfree (it);
1646 return;
1647 }
1648
1649 prev_next_p = &it->next;
1650 it = *prev_next_p;
1651 }
1652 }
1653
1654 static void
1655 infrun_inferior_exit (struct inferior *inf)
1656 {
1657 remove_displaced_stepping_state (inf->pid);
1658 }
1659
1660 /* If ON, and the architecture supports it, GDB will use displaced
1661 stepping to step over breakpoints. If OFF, or if the architecture
1662 doesn't support it, GDB will instead use the traditional
1663 hold-and-step approach. If AUTO (which is the default), GDB will
1664 decide which technique to use to step over breakpoints depending on
1665 which of all-stop or non-stop mode is active --- displaced stepping
1666 in non-stop mode; hold-and-step in all-stop mode. */
1667
1668 static enum auto_boolean can_use_displaced_stepping = AUTO_BOOLEAN_AUTO;
1669
1670 static void
1671 show_can_use_displaced_stepping (struct ui_file *file, int from_tty,
1672 struct cmd_list_element *c,
1673 const char *value)
1674 {
1675 if (can_use_displaced_stepping == AUTO_BOOLEAN_AUTO)
1676 fprintf_filtered (file,
1677 _("Debugger's willingness to use displaced stepping "
1678 "to step over breakpoints is %s (currently %s).\n"),
1679 value, target_is_non_stop_p () ? "on" : "off");
1680 else
1681 fprintf_filtered (file,
1682 _("Debugger's willingness to use displaced stepping "
1683 "to step over breakpoints is %s.\n"), value);
1684 }
1685
1686 /* Return non-zero if displaced stepping can/should be used to step
1687 over breakpoints of thread TP. */
1688
1689 static int
1690 use_displaced_stepping (struct thread_info *tp)
1691 {
1692 struct regcache *regcache = get_thread_regcache (tp->ptid);
1693 struct gdbarch *gdbarch = regcache->arch ();
1694 struct displaced_step_inferior_state *displaced_state;
1695
1696 displaced_state = get_displaced_stepping_state (ptid_get_pid (tp->ptid));
1697
1698 return (((can_use_displaced_stepping == AUTO_BOOLEAN_AUTO
1699 && target_is_non_stop_p ())
1700 || can_use_displaced_stepping == AUTO_BOOLEAN_TRUE)
1701 && gdbarch_displaced_step_copy_insn_p (gdbarch)
1702 && find_record_target () == NULL
1703 && (displaced_state == NULL
1704 || !displaced_state->failed_before));
1705 }
1706
1707 /* Clean out any stray displaced stepping state. */
1708 static void
1709 displaced_step_clear (struct displaced_step_inferior_state *displaced)
1710 {
1711 /* Indicate that there is no cleanup pending. */
1712 displaced->step_ptid = null_ptid;
1713
1714 delete displaced->step_closure;
1715 displaced->step_closure = NULL;
1716 }
1717
1718 static void
1719 displaced_step_clear_cleanup (void *arg)
1720 {
1721 struct displaced_step_inferior_state *state
1722 = (struct displaced_step_inferior_state *) arg;
1723
1724 displaced_step_clear (state);
1725 }
1726
1727 /* Dump LEN bytes at BUF in hex to FILE, followed by a newline. */
1728 void
1729 displaced_step_dump_bytes (struct ui_file *file,
1730 const gdb_byte *buf,
1731 size_t len)
1732 {
1733 int i;
1734
1735 for (i = 0; i < len; i++)
1736 fprintf_unfiltered (file, "%02x ", buf[i]);
1737 fputs_unfiltered ("\n", file);
1738 }
1739
1740 /* Prepare to single-step, using displaced stepping.
1741
1742 Note that we cannot use displaced stepping when we have a signal to
1743 deliver. If we have a signal to deliver and an instruction to step
1744 over, then after the step, there will be no indication from the
1745 target whether the thread entered a signal handler or ignored the
1746 signal and stepped over the instruction successfully --- both cases
1747 result in a simple SIGTRAP. In the first case we mustn't do a
1748 fixup, and in the second case we must --- but we can't tell which.
1749 Comments in the code for 'random signals' in handle_inferior_event
1750 explain how we handle this case instead.
1751
1752 Returns 1 if preparing was successful -- this thread is going to be
1753 stepped now; 0 if displaced stepping this thread got queued; or -1
1754 if this instruction can't be displaced stepped. */
1755
1756 static int
1757 displaced_step_prepare_throw (ptid_t ptid)
1758 {
1759 struct cleanup *ignore_cleanups;
1760 struct thread_info *tp = find_thread_ptid (ptid);
1761 struct regcache *regcache = get_thread_regcache (ptid);
1762 struct gdbarch *gdbarch = regcache->arch ();
1763 const address_space *aspace = regcache->aspace ();
1764 CORE_ADDR original, copy;
1765 ULONGEST len;
1766 struct displaced_step_closure *closure;
1767 struct displaced_step_inferior_state *displaced;
1768 int status;
1769
1770 /* We should never reach this function if the architecture does not
1771 support displaced stepping. */
1772 gdb_assert (gdbarch_displaced_step_copy_insn_p (gdbarch));
1773
1774 /* Nor if the thread isn't meant to step over a breakpoint. */
1775 gdb_assert (tp->control.trap_expected);
1776
1777 /* Disable range stepping while executing in the scratch pad. We
1778 want a single-step even if executing the displaced instruction in
1779 the scratch buffer lands within the stepping range (e.g., a
1780 jump/branch). */
1781 tp->control.may_range_step = 0;
1782
1783 /* We have to displaced step one thread at a time, as we only have
1784 access to a single scratch space per inferior. */
1785
1786 displaced = add_displaced_stepping_state (ptid_get_pid (ptid));
1787
1788 if (!ptid_equal (displaced->step_ptid, null_ptid))
1789 {
1790 /* Already waiting for a displaced step to finish. Defer this
1791 request and place in queue. */
1792
1793 if (debug_displaced)
1794 fprintf_unfiltered (gdb_stdlog,
1795 "displaced: deferring step of %s\n",
1796 target_pid_to_str (ptid));
1797
1798 thread_step_over_chain_enqueue (tp);
1799 return 0;
1800 }
1801 else
1802 {
1803 if (debug_displaced)
1804 fprintf_unfiltered (gdb_stdlog,
1805 "displaced: stepping %s now\n",
1806 target_pid_to_str (ptid));
1807 }
1808
1809 displaced_step_clear (displaced);
1810
1811 scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
1812 inferior_ptid = ptid;
1813
1814 original = regcache_read_pc (regcache);
1815
1816 copy = gdbarch_displaced_step_location (gdbarch);
1817 len = gdbarch_max_insn_length (gdbarch);
1818
1819 if (breakpoint_in_range_p (aspace, copy, len))
1820 {
1821 /* There's a breakpoint set in the scratch pad location range
1822 (which is usually around the entry point). We'd either
1823 install it before resuming, which would overwrite/corrupt the
1824 scratch pad, or if it was already inserted, this displaced
1825 step would overwrite it. The latter is OK in the sense that
1826 we already assume that no thread is going to execute the code
1827 in the scratch pad range (after initial startup) anyway, but
1828 the former is unacceptable. Simply punt and fallback to
1829 stepping over this breakpoint in-line. */
1830 if (debug_displaced)
1831 {
1832 fprintf_unfiltered (gdb_stdlog,
1833 "displaced: breakpoint set in scratch pad. "
1834 "Stepping over breakpoint in-line instead.\n");
1835 }
1836
1837 return -1;
1838 }
1839
1840 /* Save the original contents of the copy area. */
1841 displaced->step_saved_copy = (gdb_byte *) xmalloc (len);
1842 ignore_cleanups = make_cleanup (free_current_contents,
1843 &displaced->step_saved_copy);
1844 status = target_read_memory (copy, displaced->step_saved_copy, len);
1845 if (status != 0)
1846 throw_error (MEMORY_ERROR,
1847 _("Error accessing memory address %s (%s) for "
1848 "displaced-stepping scratch space."),
1849 paddress (gdbarch, copy), safe_strerror (status));
1850 if (debug_displaced)
1851 {
1852 fprintf_unfiltered (gdb_stdlog, "displaced: saved %s: ",
1853 paddress (gdbarch, copy));
1854 displaced_step_dump_bytes (gdb_stdlog,
1855 displaced->step_saved_copy,
1856 len);
1857 };
1858
1859 closure = gdbarch_displaced_step_copy_insn (gdbarch,
1860 original, copy, regcache);
1861 if (closure == NULL)
1862 {
1863 /* The architecture doesn't know how or want to displaced step
1864 this instruction or instruction sequence. Fallback to
1865 stepping over the breakpoint in-line. */
1866 do_cleanups (ignore_cleanups);
1867 return -1;
1868 }
1869
1870 /* Save the information we need to fix things up if the step
1871 succeeds. */
1872 displaced->step_ptid = ptid;
1873 displaced->step_gdbarch = gdbarch;
1874 displaced->step_closure = closure;
1875 displaced->step_original = original;
1876 displaced->step_copy = copy;
1877
1878 make_cleanup (displaced_step_clear_cleanup, displaced);
1879
1880 /* Resume execution at the copy. */
1881 regcache_write_pc (regcache, copy);
1882
1883 discard_cleanups (ignore_cleanups);
1884
1885 if (debug_displaced)
1886 fprintf_unfiltered (gdb_stdlog, "displaced: displaced pc to %s\n",
1887 paddress (gdbarch, copy));
1888
1889 return 1;
1890 }
1891
1892 /* Wrapper for displaced_step_prepare_throw that disabled further
1893 attempts at displaced stepping if we get a memory error. */
1894
1895 static int
1896 displaced_step_prepare (ptid_t ptid)
1897 {
1898 int prepared = -1;
1899
1900 TRY
1901 {
1902 prepared = displaced_step_prepare_throw (ptid);
1903 }
1904 CATCH (ex, RETURN_MASK_ERROR)
1905 {
1906 struct displaced_step_inferior_state *displaced_state;
1907
1908 if (ex.error != MEMORY_ERROR
1909 && ex.error != NOT_SUPPORTED_ERROR)
1910 throw_exception (ex);
1911
1912 if (debug_infrun)
1913 {
1914 fprintf_unfiltered (gdb_stdlog,
1915 "infrun: disabling displaced stepping: %s\n",
1916 ex.message);
1917 }
1918
1919 /* Be verbose if "set displaced-stepping" is "on", silent if
1920 "auto". */
1921 if (can_use_displaced_stepping == AUTO_BOOLEAN_TRUE)
1922 {
1923 warning (_("disabling displaced stepping: %s"),
1924 ex.message);
1925 }
1926
1927 /* Disable further displaced stepping attempts. */
1928 displaced_state
1929 = get_displaced_stepping_state (ptid_get_pid (ptid));
1930 displaced_state->failed_before = 1;
1931 }
1932 END_CATCH
1933
1934 return prepared;
1935 }
1936
1937 static void
1938 write_memory_ptid (ptid_t ptid, CORE_ADDR memaddr,
1939 const gdb_byte *myaddr, int len)
1940 {
1941 scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
1942
1943 inferior_ptid = ptid;
1944 write_memory (memaddr, myaddr, len);
1945 }
1946
1947 /* Restore the contents of the copy area for thread PTID. */
1948
1949 static void
1950 displaced_step_restore (struct displaced_step_inferior_state *displaced,
1951 ptid_t ptid)
1952 {
1953 ULONGEST len = gdbarch_max_insn_length (displaced->step_gdbarch);
1954
1955 write_memory_ptid (ptid, displaced->step_copy,
1956 displaced->step_saved_copy, len);
1957 if (debug_displaced)
1958 fprintf_unfiltered (gdb_stdlog, "displaced: restored %s %s\n",
1959 target_pid_to_str (ptid),
1960 paddress (displaced->step_gdbarch,
1961 displaced->step_copy));
1962 }
1963
1964 /* If we displaced stepped an instruction successfully, adjust
1965 registers and memory to yield the same effect the instruction would
1966 have had if we had executed it at its original address, and return
1967 1. If the instruction didn't complete, relocate the PC and return
1968 -1. If the thread wasn't displaced stepping, return 0. */
1969
1970 static int
1971 displaced_step_fixup (ptid_t event_ptid, enum gdb_signal signal)
1972 {
1973 struct cleanup *old_cleanups;
1974 struct displaced_step_inferior_state *displaced
1975 = get_displaced_stepping_state (ptid_get_pid (event_ptid));
1976 int ret;
1977
1978 /* Was any thread of this process doing a displaced step? */
1979 if (displaced == NULL)
1980 return 0;
1981
1982 /* Was this event for the pid we displaced? */
1983 if (ptid_equal (displaced->step_ptid, null_ptid)
1984 || ! ptid_equal (displaced->step_ptid, event_ptid))
1985 return 0;
1986
1987 old_cleanups = make_cleanup (displaced_step_clear_cleanup, displaced);
1988
1989 displaced_step_restore (displaced, displaced->step_ptid);
1990
1991 /* Fixup may need to read memory/registers. Switch to the thread
1992 that we're fixing up. Also, target_stopped_by_watchpoint checks
1993 the current thread. */
1994 switch_to_thread (event_ptid);
1995
1996 /* Did the instruction complete successfully? */
1997 if (signal == GDB_SIGNAL_TRAP
1998 && !(target_stopped_by_watchpoint ()
1999 && (gdbarch_have_nonsteppable_watchpoint (displaced->step_gdbarch)
2000 || target_have_steppable_watchpoint)))
2001 {
2002 /* Fix up the resulting state. */
2003 gdbarch_displaced_step_fixup (displaced->step_gdbarch,
2004 displaced->step_closure,
2005 displaced->step_original,
2006 displaced->step_copy,
2007 get_thread_regcache (displaced->step_ptid));
2008 ret = 1;
2009 }
2010 else
2011 {
2012 /* Since the instruction didn't complete, all we can do is
2013 relocate the PC. */
2014 struct regcache *regcache = get_thread_regcache (event_ptid);
2015 CORE_ADDR pc = regcache_read_pc (regcache);
2016
2017 pc = displaced->step_original + (pc - displaced->step_copy);
2018 regcache_write_pc (regcache, pc);
2019 ret = -1;
2020 }
2021
2022 do_cleanups (old_cleanups);
2023
2024 displaced->step_ptid = null_ptid;
2025
2026 return ret;
2027 }
2028
2029 /* Data to be passed around while handling an event. This data is
2030 discarded between events. */
2031 struct execution_control_state
2032 {
2033 ptid_t ptid;
2034 /* The thread that got the event, if this was a thread event; NULL
2035 otherwise. */
2036 struct thread_info *event_thread;
2037
2038 struct target_waitstatus ws;
2039 int stop_func_filled_in;
2040 CORE_ADDR stop_func_start;
2041 CORE_ADDR stop_func_end;
2042 const char *stop_func_name;
2043 int wait_some_more;
2044
2045 /* True if the event thread hit the single-step breakpoint of
2046 another thread. Thus the event doesn't cause a stop, the thread
2047 needs to be single-stepped past the single-step breakpoint before
2048 we can switch back to the original stepping thread. */
2049 int hit_singlestep_breakpoint;
2050 };
2051
2052 /* Clear ECS and set it to point at TP. */
2053
2054 static void
2055 reset_ecs (struct execution_control_state *ecs, struct thread_info *tp)
2056 {
2057 memset (ecs, 0, sizeof (*ecs));
2058 ecs->event_thread = tp;
2059 ecs->ptid = tp->ptid;
2060 }
2061
2062 static void keep_going_pass_signal (struct execution_control_state *ecs);
2063 static void prepare_to_wait (struct execution_control_state *ecs);
2064 static int keep_going_stepped_thread (struct thread_info *tp);
2065 static step_over_what thread_still_needs_step_over (struct thread_info *tp);
2066
2067 /* Are there any pending step-over requests? If so, run all we can
2068 now and return true. Otherwise, return false. */
2069
2070 static int
2071 start_step_over (void)
2072 {
2073 struct thread_info *tp, *next;
2074
2075 /* Don't start a new step-over if we already have an in-line
2076 step-over operation ongoing. */
2077 if (step_over_info_valid_p ())
2078 return 0;
2079
2080 for (tp = step_over_queue_head; tp != NULL; tp = next)
2081 {
2082 struct execution_control_state ecss;
2083 struct execution_control_state *ecs = &ecss;
2084 step_over_what step_what;
2085 int must_be_in_line;
2086
2087 gdb_assert (!tp->stop_requested);
2088
2089 next = thread_step_over_chain_next (tp);
2090
2091 /* If this inferior already has a displaced step in process,
2092 don't start a new one. */
2093 if (displaced_step_in_progress (ptid_get_pid (tp->ptid)))
2094 continue;
2095
2096 step_what = thread_still_needs_step_over (tp);
2097 must_be_in_line = ((step_what & STEP_OVER_WATCHPOINT)
2098 || ((step_what & STEP_OVER_BREAKPOINT)
2099 && !use_displaced_stepping (tp)));
2100
2101 /* We currently stop all threads of all processes to step-over
2102 in-line. If we need to start a new in-line step-over, let
2103 any pending displaced steps finish first. */
2104 if (must_be_in_line && displaced_step_in_progress_any_inferior ())
2105 return 0;
2106
2107 thread_step_over_chain_remove (tp);
2108
2109 if (step_over_queue_head == NULL)
2110 {
2111 if (debug_infrun)
2112 fprintf_unfiltered (gdb_stdlog,
2113 "infrun: step-over queue now empty\n");
2114 }
2115
2116 if (tp->control.trap_expected
2117 || tp->resumed
2118 || tp->executing)
2119 {
2120 internal_error (__FILE__, __LINE__,
2121 "[%s] has inconsistent state: "
2122 "trap_expected=%d, resumed=%d, executing=%d\n",
2123 target_pid_to_str (tp->ptid),
2124 tp->control.trap_expected,
2125 tp->resumed,
2126 tp->executing);
2127 }
2128
2129 if (debug_infrun)
2130 fprintf_unfiltered (gdb_stdlog,
2131 "infrun: resuming [%s] for step-over\n",
2132 target_pid_to_str (tp->ptid));
2133
2134 /* keep_going_pass_signal skips the step-over if the breakpoint
2135 is no longer inserted. In all-stop, we want to keep looking
2136 for a thread that needs a step-over instead of resuming TP,
2137 because we wouldn't be able to resume anything else until the
2138 target stops again. In non-stop, the resume always resumes
2139 only TP, so it's OK to let the thread resume freely. */
2140 if (!target_is_non_stop_p () && !step_what)
2141 continue;
2142
2143 switch_to_thread (tp->ptid);
2144 reset_ecs (ecs, tp);
2145 keep_going_pass_signal (ecs);
2146
2147 if (!ecs->wait_some_more)
2148 error (_("Command aborted."));
2149
2150 gdb_assert (tp->resumed);
2151
2152 /* If we started a new in-line step-over, we're done. */
2153 if (step_over_info_valid_p ())
2154 {
2155 gdb_assert (tp->control.trap_expected);
2156 return 1;
2157 }
2158
2159 if (!target_is_non_stop_p ())
2160 {
2161 /* On all-stop, shouldn't have resumed unless we needed a
2162 step over. */
2163 gdb_assert (tp->control.trap_expected
2164 || tp->step_after_step_resume_breakpoint);
2165
2166 /* With remote targets (at least), in all-stop, we can't
2167 issue any further remote commands until the program stops
2168 again. */
2169 return 1;
2170 }
2171
2172 /* Either the thread no longer needed a step-over, or a new
2173 displaced stepping sequence started. Even in the latter
2174 case, continue looking. Maybe we can also start another
2175 displaced step on a thread of other process. */
2176 }
2177
2178 return 0;
2179 }
2180
2181 /* Update global variables holding ptids to hold NEW_PTID if they were
2182 holding OLD_PTID. */
2183 static void
2184 infrun_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid)
2185 {
2186 struct displaced_step_inferior_state *displaced;
2187
2188 if (ptid_equal (inferior_ptid, old_ptid))
2189 inferior_ptid = new_ptid;
2190
2191 for (displaced = displaced_step_inferior_states;
2192 displaced;
2193 displaced = displaced->next)
2194 {
2195 if (ptid_equal (displaced->step_ptid, old_ptid))
2196 displaced->step_ptid = new_ptid;
2197 }
2198 }
2199
2200 \f
2201 /* Resuming. */
2202
2203 /* Things to clean up if we QUIT out of resume (). */
2204 static void
2205 resume_cleanups (void *ignore)
2206 {
2207 if (!ptid_equal (inferior_ptid, null_ptid))
2208 delete_single_step_breakpoints (inferior_thread ());
2209
2210 normal_stop ();
2211 }
2212
2213 static const char schedlock_off[] = "off";
2214 static const char schedlock_on[] = "on";
2215 static const char schedlock_step[] = "step";
2216 static const char schedlock_replay[] = "replay";
2217 static const char *const scheduler_enums[] = {
2218 schedlock_off,
2219 schedlock_on,
2220 schedlock_step,
2221 schedlock_replay,
2222 NULL
2223 };
2224 static const char *scheduler_mode = schedlock_replay;
2225 static void
2226 show_scheduler_mode (struct ui_file *file, int from_tty,
2227 struct cmd_list_element *c, const char *value)
2228 {
2229 fprintf_filtered (file,
2230 _("Mode for locking scheduler "
2231 "during execution is \"%s\".\n"),
2232 value);
2233 }
2234
2235 static void
2236 set_schedlock_func (char *args, int from_tty, struct cmd_list_element *c)
2237 {
2238 if (!target_can_lock_scheduler)
2239 {
2240 scheduler_mode = schedlock_off;
2241 error (_("Target '%s' cannot support this command."), target_shortname);
2242 }
2243 }
2244
2245 /* True if execution commands resume all threads of all processes by
2246 default; otherwise, resume only threads of the current inferior
2247 process. */
2248 int sched_multi = 0;
2249
2250 /* Try to setup for software single stepping over the specified location.
2251 Return 1 if target_resume() should use hardware single step.
2252
2253 GDBARCH the current gdbarch.
2254 PC the location to step over. */
2255
2256 static int
2257 maybe_software_singlestep (struct gdbarch *gdbarch, CORE_ADDR pc)
2258 {
2259 int hw_step = 1;
2260
2261 if (execution_direction == EXEC_FORWARD
2262 && gdbarch_software_single_step_p (gdbarch))
2263 hw_step = !insert_single_step_breakpoints (gdbarch);
2264
2265 return hw_step;
2266 }
2267
2268 /* See infrun.h. */
2269
2270 ptid_t
2271 user_visible_resume_ptid (int step)
2272 {
2273 ptid_t resume_ptid;
2274
2275 if (non_stop)
2276 {
2277 /* With non-stop mode on, threads are always handled
2278 individually. */
2279 resume_ptid = inferior_ptid;
2280 }
2281 else if ((scheduler_mode == schedlock_on)
2282 || (scheduler_mode == schedlock_step && step))
2283 {
2284 /* User-settable 'scheduler' mode requires solo thread
2285 resume. */
2286 resume_ptid = inferior_ptid;
2287 }
2288 else if ((scheduler_mode == schedlock_replay)
2289 && target_record_will_replay (minus_one_ptid, execution_direction))
2290 {
2291 /* User-settable 'scheduler' mode requires solo thread resume in replay
2292 mode. */
2293 resume_ptid = inferior_ptid;
2294 }
2295 else if (!sched_multi && target_supports_multi_process ())
2296 {
2297 /* Resume all threads of the current process (and none of other
2298 processes). */
2299 resume_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
2300 }
2301 else
2302 {
2303 /* Resume all threads of all processes. */
2304 resume_ptid = RESUME_ALL;
2305 }
2306
2307 return resume_ptid;
2308 }
2309
2310 /* Return a ptid representing the set of threads that we will resume,
2311 in the perspective of the target, assuming run control handling
2312 does not require leaving some threads stopped (e.g., stepping past
2313 breakpoint). USER_STEP indicates whether we're about to start the
2314 target for a stepping command. */
2315
2316 static ptid_t
2317 internal_resume_ptid (int user_step)
2318 {
2319 /* In non-stop, we always control threads individually. Note that
2320 the target may always work in non-stop mode even with "set
2321 non-stop off", in which case user_visible_resume_ptid could
2322 return a wildcard ptid. */
2323 if (target_is_non_stop_p ())
2324 return inferior_ptid;
2325 else
2326 return user_visible_resume_ptid (user_step);
2327 }
2328
2329 /* Wrapper for target_resume, that handles infrun-specific
2330 bookkeeping. */
2331
2332 static void
2333 do_target_resume (ptid_t resume_ptid, int step, enum gdb_signal sig)
2334 {
2335 struct thread_info *tp = inferior_thread ();
2336
2337 gdb_assert (!tp->stop_requested);
2338
2339 /* Install inferior's terminal modes. */
2340 target_terminal::inferior ();
2341
2342 /* Avoid confusing the next resume, if the next stop/resume
2343 happens to apply to another thread. */
2344 tp->suspend.stop_signal = GDB_SIGNAL_0;
2345
2346 /* Advise target which signals may be handled silently.
2347
2348 If we have removed breakpoints because we are stepping over one
2349 in-line (in any thread), we need to receive all signals to avoid
2350 accidentally skipping a breakpoint during execution of a signal
2351 handler.
2352
2353 Likewise if we're displaced stepping, otherwise a trap for a
2354 breakpoint in a signal handler might be confused with the
2355 displaced step finishing. We don't make the displaced_step_fixup
2356 step distinguish the cases instead, because:
2357
2358 - a backtrace while stopped in the signal handler would show the
2359 scratch pad as frame older than the signal handler, instead of
2360 the real mainline code.
2361
2362 - when the thread is later resumed, the signal handler would
2363 return to the scratch pad area, which would no longer be
2364 valid. */
2365 if (step_over_info_valid_p ()
2366 || displaced_step_in_progress (ptid_get_pid (tp->ptid)))
2367 target_pass_signals (0, NULL);
2368 else
2369 target_pass_signals ((int) GDB_SIGNAL_LAST, signal_pass);
2370
2371 target_resume (resume_ptid, step, sig);
2372
2373 target_commit_resume ();
2374 }
2375
2376 /* Resume the inferior, but allow a QUIT. This is useful if the user
2377 wants to interrupt some lengthy single-stepping operation
2378 (for child processes, the SIGINT goes to the inferior, and so
2379 we get a SIGINT random_signal, but for remote debugging and perhaps
2380 other targets, that's not true).
2381
2382 SIG is the signal to give the inferior (zero for none). */
2383 void
2384 resume (enum gdb_signal sig)
2385 {
2386 struct cleanup *old_cleanups = make_cleanup (resume_cleanups, 0);
2387 struct regcache *regcache = get_current_regcache ();
2388 struct gdbarch *gdbarch = regcache->arch ();
2389 struct thread_info *tp = inferior_thread ();
2390 CORE_ADDR pc = regcache_read_pc (regcache);
2391 const address_space *aspace = regcache->aspace ();
2392 ptid_t resume_ptid;
2393 /* This represents the user's step vs continue request. When
2394 deciding whether "set scheduler-locking step" applies, it's the
2395 user's intention that counts. */
2396 const int user_step = tp->control.stepping_command;
2397 /* This represents what we'll actually request the target to do.
2398 This can decay from a step to a continue, if e.g., we need to
2399 implement single-stepping with breakpoints (software
2400 single-step). */
2401 int step;
2402
2403 gdb_assert (!tp->stop_requested);
2404 gdb_assert (!thread_is_in_step_over_chain (tp));
2405
2406 QUIT;
2407
2408 if (tp->suspend.waitstatus_pending_p)
2409 {
2410 if (debug_infrun)
2411 {
2412 std::string statstr
2413 = target_waitstatus_to_string (&tp->suspend.waitstatus);
2414
2415 fprintf_unfiltered (gdb_stdlog,
2416 "infrun: resume: thread %s has pending wait "
2417 "status %s (currently_stepping=%d).\n",
2418 target_pid_to_str (tp->ptid), statstr.c_str (),
2419 currently_stepping (tp));
2420 }
2421
2422 tp->resumed = 1;
2423
2424 /* FIXME: What should we do if we are supposed to resume this
2425 thread with a signal? Maybe we should maintain a queue of
2426 pending signals to deliver. */
2427 if (sig != GDB_SIGNAL_0)
2428 {
2429 warning (_("Couldn't deliver signal %s to %s."),
2430 gdb_signal_to_name (sig), target_pid_to_str (tp->ptid));
2431 }
2432
2433 tp->suspend.stop_signal = GDB_SIGNAL_0;
2434 discard_cleanups (old_cleanups);
2435
2436 if (target_can_async_p ())
2437 target_async (1);
2438 return;
2439 }
2440
2441 tp->stepped_breakpoint = 0;
2442
2443 /* Depends on stepped_breakpoint. */
2444 step = currently_stepping (tp);
2445
2446 if (current_inferior ()->waiting_for_vfork_done)
2447 {
2448 /* Don't try to single-step a vfork parent that is waiting for
2449 the child to get out of the shared memory region (by exec'ing
2450 or exiting). This is particularly important on software
2451 single-step archs, as the child process would trip on the
2452 software single step breakpoint inserted for the parent
2453 process. Since the parent will not actually execute any
2454 instruction until the child is out of the shared region (such
2455 are vfork's semantics), it is safe to simply continue it.
2456 Eventually, we'll see a TARGET_WAITKIND_VFORK_DONE event for
2457 the parent, and tell it to `keep_going', which automatically
2458 re-sets it stepping. */
2459 if (debug_infrun)
2460 fprintf_unfiltered (gdb_stdlog,
2461 "infrun: resume : clear step\n");
2462 step = 0;
2463 }
2464
2465 if (debug_infrun)
2466 fprintf_unfiltered (gdb_stdlog,
2467 "infrun: resume (step=%d, signal=%s), "
2468 "trap_expected=%d, current thread [%s] at %s\n",
2469 step, gdb_signal_to_symbol_string (sig),
2470 tp->control.trap_expected,
2471 target_pid_to_str (inferior_ptid),
2472 paddress (gdbarch, pc));
2473
2474 /* Normally, by the time we reach `resume', the breakpoints are either
2475 removed or inserted, as appropriate. The exception is if we're sitting
2476 at a permanent breakpoint; we need to step over it, but permanent
2477 breakpoints can't be removed. So we have to test for it here. */
2478 if (breakpoint_here_p (aspace, pc) == permanent_breakpoint_here)
2479 {
2480 if (sig != GDB_SIGNAL_0)
2481 {
2482 /* We have a signal to pass to the inferior. The resume
2483 may, or may not take us to the signal handler. If this
2484 is a step, we'll need to stop in the signal handler, if
2485 there's one, (if the target supports stepping into
2486 handlers), or in the next mainline instruction, if
2487 there's no handler. If this is a continue, we need to be
2488 sure to run the handler with all breakpoints inserted.
2489 In all cases, set a breakpoint at the current address
2490 (where the handler returns to), and once that breakpoint
2491 is hit, resume skipping the permanent breakpoint. If
2492 that breakpoint isn't hit, then we've stepped into the
2493 signal handler (or hit some other event). We'll delete
2494 the step-resume breakpoint then. */
2495
2496 if (debug_infrun)
2497 fprintf_unfiltered (gdb_stdlog,
2498 "infrun: resume: skipping permanent breakpoint, "
2499 "deliver signal first\n");
2500
2501 clear_step_over_info ();
2502 tp->control.trap_expected = 0;
2503
2504 if (tp->control.step_resume_breakpoint == NULL)
2505 {
2506 /* Set a "high-priority" step-resume, as we don't want
2507 user breakpoints at PC to trigger (again) when this
2508 hits. */
2509 insert_hp_step_resume_breakpoint_at_frame (get_current_frame ());
2510 gdb_assert (tp->control.step_resume_breakpoint->loc->permanent);
2511
2512 tp->step_after_step_resume_breakpoint = step;
2513 }
2514
2515 insert_breakpoints ();
2516 }
2517 else
2518 {
2519 /* There's no signal to pass, we can go ahead and skip the
2520 permanent breakpoint manually. */
2521 if (debug_infrun)
2522 fprintf_unfiltered (gdb_stdlog,
2523 "infrun: resume: skipping permanent breakpoint\n");
2524 gdbarch_skip_permanent_breakpoint (gdbarch, regcache);
2525 /* Update pc to reflect the new address from which we will
2526 execute instructions. */
2527 pc = regcache_read_pc (regcache);
2528
2529 if (step)
2530 {
2531 /* We've already advanced the PC, so the stepping part
2532 is done. Now we need to arrange for a trap to be
2533 reported to handle_inferior_event. Set a breakpoint
2534 at the current PC, and run to it. Don't update
2535 prev_pc, because if we end in
2536 switch_back_to_stepped_thread, we want the "expected
2537 thread advanced also" branch to be taken. IOW, we
2538 don't want this thread to step further from PC
2539 (overstep). */
2540 gdb_assert (!step_over_info_valid_p ());
2541 insert_single_step_breakpoint (gdbarch, aspace, pc);
2542 insert_breakpoints ();
2543
2544 resume_ptid = internal_resume_ptid (user_step);
2545 do_target_resume (resume_ptid, 0, GDB_SIGNAL_0);
2546 discard_cleanups (old_cleanups);
2547 tp->resumed = 1;
2548 return;
2549 }
2550 }
2551 }
2552
2553 /* If we have a breakpoint to step over, make sure to do a single
2554 step only. Same if we have software watchpoints. */
2555 if (tp->control.trap_expected || bpstat_should_step ())
2556 tp->control.may_range_step = 0;
2557
2558 /* If enabled, step over breakpoints by executing a copy of the
2559 instruction at a different address.
2560
2561 We can't use displaced stepping when we have a signal to deliver;
2562 the comments for displaced_step_prepare explain why. The
2563 comments in the handle_inferior event for dealing with 'random
2564 signals' explain what we do instead.
2565
2566 We can't use displaced stepping when we are waiting for vfork_done
2567 event, displaced stepping breaks the vfork child similarly as single
2568 step software breakpoint. */
2569 if (tp->control.trap_expected
2570 && use_displaced_stepping (tp)
2571 && !step_over_info_valid_p ()
2572 && sig == GDB_SIGNAL_0
2573 && !current_inferior ()->waiting_for_vfork_done)
2574 {
2575 int prepared = displaced_step_prepare (inferior_ptid);
2576
2577 if (prepared == 0)
2578 {
2579 if (debug_infrun)
2580 fprintf_unfiltered (gdb_stdlog,
2581 "Got placed in step-over queue\n");
2582
2583 tp->control.trap_expected = 0;
2584 discard_cleanups (old_cleanups);
2585 return;
2586 }
2587 else if (prepared < 0)
2588 {
2589 /* Fallback to stepping over the breakpoint in-line. */
2590
2591 if (target_is_non_stop_p ())
2592 stop_all_threads ();
2593
2594 set_step_over_info (regcache->aspace (),
2595 regcache_read_pc (regcache), 0, tp->global_num);
2596
2597 step = maybe_software_singlestep (gdbarch, pc);
2598
2599 insert_breakpoints ();
2600 }
2601 else if (prepared > 0)
2602 {
2603 struct displaced_step_inferior_state *displaced;
2604
2605 /* Update pc to reflect the new address from which we will
2606 execute instructions due to displaced stepping. */
2607 pc = regcache_read_pc (get_thread_regcache (inferior_ptid));
2608
2609 displaced = get_displaced_stepping_state (ptid_get_pid (inferior_ptid));
2610 step = gdbarch_displaced_step_hw_singlestep (gdbarch,
2611 displaced->step_closure);
2612 }
2613 }
2614
2615 /* Do we need to do it the hard way, w/temp breakpoints? */
2616 else if (step)
2617 step = maybe_software_singlestep (gdbarch, pc);
2618
2619 /* Currently, our software single-step implementation leads to different
2620 results than hardware single-stepping in one situation: when stepping
2621 into delivering a signal which has an associated signal handler,
2622 hardware single-step will stop at the first instruction of the handler,
2623 while software single-step will simply skip execution of the handler.
2624
2625 For now, this difference in behavior is accepted since there is no
2626 easy way to actually implement single-stepping into a signal handler
2627 without kernel support.
2628
2629 However, there is one scenario where this difference leads to follow-on
2630 problems: if we're stepping off a breakpoint by removing all breakpoints
2631 and then single-stepping. In this case, the software single-step
2632 behavior means that even if there is a *breakpoint* in the signal
2633 handler, GDB still would not stop.
2634
2635 Fortunately, we can at least fix this particular issue. We detect
2636 here the case where we are about to deliver a signal while software
2637 single-stepping with breakpoints removed. In this situation, we
2638 revert the decisions to remove all breakpoints and insert single-
2639 step breakpoints, and instead we install a step-resume breakpoint
2640 at the current address, deliver the signal without stepping, and
2641 once we arrive back at the step-resume breakpoint, actually step
2642 over the breakpoint we originally wanted to step over. */
2643 if (thread_has_single_step_breakpoints_set (tp)
2644 && sig != GDB_SIGNAL_0
2645 && step_over_info_valid_p ())
2646 {
2647 /* If we have nested signals or a pending signal is delivered
2648 immediately after a handler returns, might might already have
2649 a step-resume breakpoint set on the earlier handler. We cannot
2650 set another step-resume breakpoint; just continue on until the
2651 original breakpoint is hit. */
2652 if (tp->control.step_resume_breakpoint == NULL)
2653 {
2654 insert_hp_step_resume_breakpoint_at_frame (get_current_frame ());
2655 tp->step_after_step_resume_breakpoint = 1;
2656 }
2657
2658 delete_single_step_breakpoints (tp);
2659
2660 clear_step_over_info ();
2661 tp->control.trap_expected = 0;
2662
2663 insert_breakpoints ();
2664 }
2665
2666 /* If STEP is set, it's a request to use hardware stepping
2667 facilities. But in that case, we should never
2668 use singlestep breakpoint. */
2669 gdb_assert (!(thread_has_single_step_breakpoints_set (tp) && step));
2670
2671 /* Decide the set of threads to ask the target to resume. */
2672 if (tp->control.trap_expected)
2673 {
2674 /* We're allowing a thread to run past a breakpoint it has
2675 hit, either by single-stepping the thread with the breakpoint
2676 removed, or by displaced stepping, with the breakpoint inserted.
2677 In the former case, we need to single-step only this thread,
2678 and keep others stopped, as they can miss this breakpoint if
2679 allowed to run. That's not really a problem for displaced
2680 stepping, but, we still keep other threads stopped, in case
2681 another thread is also stopped for a breakpoint waiting for
2682 its turn in the displaced stepping queue. */
2683 resume_ptid = inferior_ptid;
2684 }
2685 else
2686 resume_ptid = internal_resume_ptid (user_step);
2687
2688 if (execution_direction != EXEC_REVERSE
2689 && step && breakpoint_inserted_here_p (aspace, pc))
2690 {
2691 /* There are two cases where we currently need to step a
2692 breakpoint instruction when we have a signal to deliver:
2693
2694 - See handle_signal_stop where we handle random signals that
2695 could take out us out of the stepping range. Normally, in
2696 that case we end up continuing (instead of stepping) over the
2697 signal handler with a breakpoint at PC, but there are cases
2698 where we should _always_ single-step, even if we have a
2699 step-resume breakpoint, like when a software watchpoint is
2700 set. Assuming single-stepping and delivering a signal at the
2701 same time would takes us to the signal handler, then we could
2702 have removed the breakpoint at PC to step over it. However,
2703 some hardware step targets (like e.g., Mac OS) can't step
2704 into signal handlers, and for those, we need to leave the
2705 breakpoint at PC inserted, as otherwise if the handler
2706 recurses and executes PC again, it'll miss the breakpoint.
2707 So we leave the breakpoint inserted anyway, but we need to
2708 record that we tried to step a breakpoint instruction, so
2709 that adjust_pc_after_break doesn't end up confused.
2710
2711 - In non-stop if we insert a breakpoint (e.g., a step-resume)
2712 in one thread after another thread that was stepping had been
2713 momentarily paused for a step-over. When we re-resume the
2714 stepping thread, it may be resumed from that address with a
2715 breakpoint that hasn't trapped yet. Seen with
2716 gdb.threads/non-stop-fair-events.exp, on targets that don't
2717 do displaced stepping. */
2718
2719 if (debug_infrun)
2720 fprintf_unfiltered (gdb_stdlog,
2721 "infrun: resume: [%s] stepped breakpoint\n",
2722 target_pid_to_str (tp->ptid));
2723
2724 tp->stepped_breakpoint = 1;
2725
2726 /* Most targets can step a breakpoint instruction, thus
2727 executing it normally. But if this one cannot, just
2728 continue and we will hit it anyway. */
2729 if (gdbarch_cannot_step_breakpoint (gdbarch))
2730 step = 0;
2731 }
2732
2733 if (debug_displaced
2734 && tp->control.trap_expected
2735 && use_displaced_stepping (tp)
2736 && !step_over_info_valid_p ())
2737 {
2738 struct regcache *resume_regcache = get_thread_regcache (tp->ptid);
2739 struct gdbarch *resume_gdbarch = resume_regcache->arch ();
2740 CORE_ADDR actual_pc = regcache_read_pc (resume_regcache);
2741 gdb_byte buf[4];
2742
2743 fprintf_unfiltered (gdb_stdlog, "displaced: run %s: ",
2744 paddress (resume_gdbarch, actual_pc));
2745 read_memory (actual_pc, buf, sizeof (buf));
2746 displaced_step_dump_bytes (gdb_stdlog, buf, sizeof (buf));
2747 }
2748
2749 if (tp->control.may_range_step)
2750 {
2751 /* If we're resuming a thread with the PC out of the step
2752 range, then we're doing some nested/finer run control
2753 operation, like stepping the thread out of the dynamic
2754 linker or the displaced stepping scratch pad. We
2755 shouldn't have allowed a range step then. */
2756 gdb_assert (pc_in_thread_step_range (pc, tp));
2757 }
2758
2759 do_target_resume (resume_ptid, step, sig);
2760 tp->resumed = 1;
2761 discard_cleanups (old_cleanups);
2762 }
2763 \f
2764 /* Proceeding. */
2765
2766 /* See infrun.h. */
2767
2768 /* Counter that tracks number of user visible stops. This can be used
2769 to tell whether a command has proceeded the inferior past the
2770 current location. This allows e.g., inferior function calls in
2771 breakpoint commands to not interrupt the command list. When the
2772 call finishes successfully, the inferior is standing at the same
2773 breakpoint as if nothing happened (and so we don't call
2774 normal_stop). */
2775 static ULONGEST current_stop_id;
2776
2777 /* See infrun.h. */
2778
2779 ULONGEST
2780 get_stop_id (void)
2781 {
2782 return current_stop_id;
2783 }
2784
2785 /* Called when we report a user visible stop. */
2786
2787 static void
2788 new_stop_id (void)
2789 {
2790 current_stop_id++;
2791 }
2792
2793 /* Clear out all variables saying what to do when inferior is continued.
2794 First do this, then set the ones you want, then call `proceed'. */
2795
2796 static void
2797 clear_proceed_status_thread (struct thread_info *tp)
2798 {
2799 if (debug_infrun)
2800 fprintf_unfiltered (gdb_stdlog,
2801 "infrun: clear_proceed_status_thread (%s)\n",
2802 target_pid_to_str (tp->ptid));
2803
2804 /* If we're starting a new sequence, then the previous finished
2805 single-step is no longer relevant. */
2806 if (tp->suspend.waitstatus_pending_p)
2807 {
2808 if (tp->suspend.stop_reason == TARGET_STOPPED_BY_SINGLE_STEP)
2809 {
2810 if (debug_infrun)
2811 fprintf_unfiltered (gdb_stdlog,
2812 "infrun: clear_proceed_status: pending "
2813 "event of %s was a finished step. "
2814 "Discarding.\n",
2815 target_pid_to_str (tp->ptid));
2816
2817 tp->suspend.waitstatus_pending_p = 0;
2818 tp->suspend.stop_reason = TARGET_STOPPED_BY_NO_REASON;
2819 }
2820 else if (debug_infrun)
2821 {
2822 std::string statstr
2823 = target_waitstatus_to_string (&tp->suspend.waitstatus);
2824
2825 fprintf_unfiltered (gdb_stdlog,
2826 "infrun: clear_proceed_status_thread: thread %s "
2827 "has pending wait status %s "
2828 "(currently_stepping=%d).\n",
2829 target_pid_to_str (tp->ptid), statstr.c_str (),
2830 currently_stepping (tp));
2831 }
2832 }
2833
2834 /* If this signal should not be seen by program, give it zero.
2835 Used for debugging signals. */
2836 if (!signal_pass_state (tp->suspend.stop_signal))
2837 tp->suspend.stop_signal = GDB_SIGNAL_0;
2838
2839 thread_fsm_delete (tp->thread_fsm);
2840 tp->thread_fsm = NULL;
2841
2842 tp->control.trap_expected = 0;
2843 tp->control.step_range_start = 0;
2844 tp->control.step_range_end = 0;
2845 tp->control.may_range_step = 0;
2846 tp->control.step_frame_id = null_frame_id;
2847 tp->control.step_stack_frame_id = null_frame_id;
2848 tp->control.step_over_calls = STEP_OVER_UNDEBUGGABLE;
2849 tp->control.step_start_function = NULL;
2850 tp->stop_requested = 0;
2851
2852 tp->control.stop_step = 0;
2853
2854 tp->control.proceed_to_finish = 0;
2855
2856 tp->control.stepping_command = 0;
2857
2858 /* Discard any remaining commands or status from previous stop. */
2859 bpstat_clear (&tp->control.stop_bpstat);
2860 }
2861
2862 void
2863 clear_proceed_status (int step)
2864 {
2865 /* With scheduler-locking replay, stop replaying other threads if we're
2866 not replaying the user-visible resume ptid.
2867
2868 This is a convenience feature to not require the user to explicitly
2869 stop replaying the other threads. We're assuming that the user's
2870 intent is to resume tracing the recorded process. */
2871 if (!non_stop && scheduler_mode == schedlock_replay
2872 && target_record_is_replaying (minus_one_ptid)
2873 && !target_record_will_replay (user_visible_resume_ptid (step),
2874 execution_direction))
2875 target_record_stop_replaying ();
2876
2877 if (!non_stop)
2878 {
2879 struct thread_info *tp;
2880 ptid_t resume_ptid;
2881
2882 resume_ptid = user_visible_resume_ptid (step);
2883
2884 /* In all-stop mode, delete the per-thread status of all threads
2885 we're about to resume, implicitly and explicitly. */
2886 ALL_NON_EXITED_THREADS (tp)
2887 {
2888 if (!ptid_match (tp->ptid, resume_ptid))
2889 continue;
2890 clear_proceed_status_thread (tp);
2891 }
2892 }
2893
2894 if (!ptid_equal (inferior_ptid, null_ptid))
2895 {
2896 struct inferior *inferior;
2897
2898 if (non_stop)
2899 {
2900 /* If in non-stop mode, only delete the per-thread status of
2901 the current thread. */
2902 clear_proceed_status_thread (inferior_thread ());
2903 }
2904
2905 inferior = current_inferior ();
2906 inferior->control.stop_soon = NO_STOP_QUIETLY;
2907 }
2908
2909 observer_notify_about_to_proceed ();
2910 }
2911
2912 /* Returns true if TP is still stopped at a breakpoint that needs
2913 stepping-over in order to make progress. If the breakpoint is gone
2914 meanwhile, we can skip the whole step-over dance. */
2915
2916 static int
2917 thread_still_needs_step_over_bp (struct thread_info *tp)
2918 {
2919 if (tp->stepping_over_breakpoint)
2920 {
2921 struct regcache *regcache = get_thread_regcache (tp->ptid);
2922
2923 if (breakpoint_here_p (regcache->aspace (),
2924 regcache_read_pc (regcache))
2925 == ordinary_breakpoint_here)
2926 return 1;
2927
2928 tp->stepping_over_breakpoint = 0;
2929 }
2930
2931 return 0;
2932 }
2933
2934 /* Check whether thread TP still needs to start a step-over in order
2935 to make progress when resumed. Returns an bitwise or of enum
2936 step_over_what bits, indicating what needs to be stepped over. */
2937
2938 static step_over_what
2939 thread_still_needs_step_over (struct thread_info *tp)
2940 {
2941 step_over_what what = 0;
2942
2943 if (thread_still_needs_step_over_bp (tp))
2944 what |= STEP_OVER_BREAKPOINT;
2945
2946 if (tp->stepping_over_watchpoint
2947 && !target_have_steppable_watchpoint)
2948 what |= STEP_OVER_WATCHPOINT;
2949
2950 return what;
2951 }
2952
2953 /* Returns true if scheduler locking applies. STEP indicates whether
2954 we're about to do a step/next-like command to a thread. */
2955
2956 static int
2957 schedlock_applies (struct thread_info *tp)
2958 {
2959 return (scheduler_mode == schedlock_on
2960 || (scheduler_mode == schedlock_step
2961 && tp->control.stepping_command)
2962 || (scheduler_mode == schedlock_replay
2963 && target_record_will_replay (minus_one_ptid,
2964 execution_direction)));
2965 }
2966
2967 /* Basic routine for continuing the program in various fashions.
2968
2969 ADDR is the address to resume at, or -1 for resume where stopped.
2970 SIGGNAL is the signal to give it, or 0 for none,
2971 or -1 for act according to how it stopped.
2972 STEP is nonzero if should trap after one instruction.
2973 -1 means return after that and print nothing.
2974 You should probably set various step_... variables
2975 before calling here, if you are stepping.
2976
2977 You should call clear_proceed_status before calling proceed. */
2978
2979 void
2980 proceed (CORE_ADDR addr, enum gdb_signal siggnal)
2981 {
2982 struct regcache *regcache;
2983 struct gdbarch *gdbarch;
2984 struct thread_info *tp;
2985 CORE_ADDR pc;
2986 ptid_t resume_ptid;
2987 struct execution_control_state ecss;
2988 struct execution_control_state *ecs = &ecss;
2989 struct cleanup *old_chain;
2990 int started;
2991
2992 /* If we're stopped at a fork/vfork, follow the branch set by the
2993 "set follow-fork-mode" command; otherwise, we'll just proceed
2994 resuming the current thread. */
2995 if (!follow_fork ())
2996 {
2997 /* The target for some reason decided not to resume. */
2998 normal_stop ();
2999 if (target_can_async_p ())
3000 inferior_event_handler (INF_EXEC_COMPLETE, NULL);
3001 return;
3002 }
3003
3004 /* We'll update this if & when we switch to a new thread. */
3005 previous_inferior_ptid = inferior_ptid;
3006
3007 regcache = get_current_regcache ();
3008 gdbarch = regcache->arch ();
3009 const address_space *aspace = regcache->aspace ();
3010
3011 pc = regcache_read_pc (regcache);
3012 tp = inferior_thread ();
3013
3014 /* Fill in with reasonable starting values. */
3015 init_thread_stepping_state (tp);
3016
3017 gdb_assert (!thread_is_in_step_over_chain (tp));
3018
3019 if (addr == (CORE_ADDR) -1)
3020 {
3021 if (pc == stop_pc
3022 && breakpoint_here_p (aspace, pc) == ordinary_breakpoint_here
3023 && execution_direction != EXEC_REVERSE)
3024 /* There is a breakpoint at the address we will resume at,
3025 step one instruction before inserting breakpoints so that
3026 we do not stop right away (and report a second hit at this
3027 breakpoint).
3028
3029 Note, we don't do this in reverse, because we won't
3030 actually be executing the breakpoint insn anyway.
3031 We'll be (un-)executing the previous instruction. */
3032 tp->stepping_over_breakpoint = 1;
3033 else if (gdbarch_single_step_through_delay_p (gdbarch)
3034 && gdbarch_single_step_through_delay (gdbarch,
3035 get_current_frame ()))
3036 /* We stepped onto an instruction that needs to be stepped
3037 again before re-inserting the breakpoint, do so. */
3038 tp->stepping_over_breakpoint = 1;
3039 }
3040 else
3041 {
3042 regcache_write_pc (regcache, addr);
3043 }
3044
3045 if (siggnal != GDB_SIGNAL_DEFAULT)
3046 tp->suspend.stop_signal = siggnal;
3047
3048 resume_ptid = user_visible_resume_ptid (tp->control.stepping_command);
3049
3050 /* If an exception is thrown from this point on, make sure to
3051 propagate GDB's knowledge of the executing state to the
3052 frontend/user running state. */
3053 old_chain = make_cleanup (finish_thread_state_cleanup, &resume_ptid);
3054
3055 /* Even if RESUME_PTID is a wildcard, and we end up resuming fewer
3056 threads (e.g., we might need to set threads stepping over
3057 breakpoints first), from the user/frontend's point of view, all
3058 threads in RESUME_PTID are now running. Unless we're calling an
3059 inferior function, as in that case we pretend the inferior
3060 doesn't run at all. */
3061 if (!tp->control.in_infcall)
3062 set_running (resume_ptid, 1);
3063
3064 if (debug_infrun)
3065 fprintf_unfiltered (gdb_stdlog,
3066 "infrun: proceed (addr=%s, signal=%s)\n",
3067 paddress (gdbarch, addr),
3068 gdb_signal_to_symbol_string (siggnal));
3069
3070 annotate_starting ();
3071
3072 /* Make sure that output from GDB appears before output from the
3073 inferior. */
3074 gdb_flush (gdb_stdout);
3075
3076 /* In a multi-threaded task we may select another thread and
3077 then continue or step.
3078
3079 But if a thread that we're resuming had stopped at a breakpoint,
3080 it will immediately cause another breakpoint stop without any
3081 execution (i.e. it will report a breakpoint hit incorrectly). So
3082 we must step over it first.
3083
3084 Look for threads other than the current (TP) that reported a
3085 breakpoint hit and haven't been resumed yet since. */
3086
3087 /* If scheduler locking applies, we can avoid iterating over all
3088 threads. */
3089 if (!non_stop && !schedlock_applies (tp))
3090 {
3091 struct thread_info *current = tp;
3092
3093 ALL_NON_EXITED_THREADS (tp)
3094 {
3095 /* Ignore the current thread here. It's handled
3096 afterwards. */
3097 if (tp == current)
3098 continue;
3099
3100 /* Ignore threads of processes we're not resuming. */
3101 if (!ptid_match (tp->ptid, resume_ptid))
3102 continue;
3103
3104 if (!thread_still_needs_step_over (tp))
3105 continue;
3106
3107 gdb_assert (!thread_is_in_step_over_chain (tp));
3108
3109 if (debug_infrun)
3110 fprintf_unfiltered (gdb_stdlog,
3111 "infrun: need to step-over [%s] first\n",
3112 target_pid_to_str (tp->ptid));
3113
3114 thread_step_over_chain_enqueue (tp);
3115 }
3116
3117 tp = current;
3118 }
3119
3120 /* Enqueue the current thread last, so that we move all other
3121 threads over their breakpoints first. */
3122 if (tp->stepping_over_breakpoint)
3123 thread_step_over_chain_enqueue (tp);
3124
3125 /* If the thread isn't started, we'll still need to set its prev_pc,
3126 so that switch_back_to_stepped_thread knows the thread hasn't
3127 advanced. Must do this before resuming any thread, as in
3128 all-stop/remote, once we resume we can't send any other packet
3129 until the target stops again. */
3130 tp->prev_pc = regcache_read_pc (regcache);
3131
3132 {
3133 scoped_restore save_defer_tc = make_scoped_defer_target_commit_resume ();
3134
3135 started = start_step_over ();
3136
3137 if (step_over_info_valid_p ())
3138 {
3139 /* Either this thread started a new in-line step over, or some
3140 other thread was already doing one. In either case, don't
3141 resume anything else until the step-over is finished. */
3142 }
3143 else if (started && !target_is_non_stop_p ())
3144 {
3145 /* A new displaced stepping sequence was started. In all-stop,
3146 we can't talk to the target anymore until it next stops. */
3147 }
3148 else if (!non_stop && target_is_non_stop_p ())
3149 {
3150 /* In all-stop, but the target is always in non-stop mode.
3151 Start all other threads that are implicitly resumed too. */
3152 ALL_NON_EXITED_THREADS (tp)
3153 {
3154 /* Ignore threads of processes we're not resuming. */
3155 if (!ptid_match (tp->ptid, resume_ptid))
3156 continue;
3157
3158 if (tp->resumed)
3159 {
3160 if (debug_infrun)
3161 fprintf_unfiltered (gdb_stdlog,
3162 "infrun: proceed: [%s] resumed\n",
3163 target_pid_to_str (tp->ptid));
3164 gdb_assert (tp->executing || tp->suspend.waitstatus_pending_p);
3165 continue;
3166 }
3167
3168 if (thread_is_in_step_over_chain (tp))
3169 {
3170 if (debug_infrun)
3171 fprintf_unfiltered (gdb_stdlog,
3172 "infrun: proceed: [%s] needs step-over\n",
3173 target_pid_to_str (tp->ptid));
3174 continue;
3175 }
3176
3177 if (debug_infrun)
3178 fprintf_unfiltered (gdb_stdlog,
3179 "infrun: proceed: resuming %s\n",
3180 target_pid_to_str (tp->ptid));
3181
3182 reset_ecs (ecs, tp);
3183 switch_to_thread (tp->ptid);
3184 keep_going_pass_signal (ecs);
3185 if (!ecs->wait_some_more)
3186 error (_("Command aborted."));
3187 }
3188 }
3189 else if (!tp->resumed && !thread_is_in_step_over_chain (tp))
3190 {
3191 /* The thread wasn't started, and isn't queued, run it now. */
3192 reset_ecs (ecs, tp);
3193 switch_to_thread (tp->ptid);
3194 keep_going_pass_signal (ecs);
3195 if (!ecs->wait_some_more)
3196 error (_("Command aborted."));
3197 }
3198 }
3199
3200 target_commit_resume ();
3201
3202 discard_cleanups (old_chain);
3203
3204 /* Tell the event loop to wait for it to stop. If the target
3205 supports asynchronous execution, it'll do this from within
3206 target_resume. */
3207 if (!target_can_async_p ())
3208 mark_async_event_handler (infrun_async_inferior_event_token);
3209 }
3210 \f
3211
3212 /* Start remote-debugging of a machine over a serial link. */
3213
3214 void
3215 start_remote (int from_tty)
3216 {
3217 struct inferior *inferior;
3218
3219 inferior = current_inferior ();
3220 inferior->control.stop_soon = STOP_QUIETLY_REMOTE;
3221
3222 /* Always go on waiting for the target, regardless of the mode. */
3223 /* FIXME: cagney/1999-09-23: At present it isn't possible to
3224 indicate to wait_for_inferior that a target should timeout if
3225 nothing is returned (instead of just blocking). Because of this,
3226 targets expecting an immediate response need to, internally, set
3227 things up so that the target_wait() is forced to eventually
3228 timeout. */
3229 /* FIXME: cagney/1999-09-24: It isn't possible for target_open() to
3230 differentiate to its caller what the state of the target is after
3231 the initial open has been performed. Here we're assuming that
3232 the target has stopped. It should be possible to eventually have
3233 target_open() return to the caller an indication that the target
3234 is currently running and GDB state should be set to the same as
3235 for an async run. */
3236 wait_for_inferior ();
3237
3238 /* Now that the inferior has stopped, do any bookkeeping like
3239 loading shared libraries. We want to do this before normal_stop,
3240 so that the displayed frame is up to date. */
3241 post_create_inferior (&current_target, from_tty);
3242
3243 normal_stop ();
3244 }
3245
3246 /* Initialize static vars when a new inferior begins. */
3247
3248 void
3249 init_wait_for_inferior (void)
3250 {
3251 /* These are meaningless until the first time through wait_for_inferior. */
3252
3253 breakpoint_init_inferior (inf_starting);
3254
3255 clear_proceed_status (0);
3256
3257 target_last_wait_ptid = minus_one_ptid;
3258
3259 previous_inferior_ptid = inferior_ptid;
3260
3261 /* Discard any skipped inlined frames. */
3262 clear_inline_frame_state (minus_one_ptid);
3263 }
3264
3265 \f
3266
3267 static void handle_inferior_event (struct execution_control_state *ecs);
3268
3269 static void handle_step_into_function (struct gdbarch *gdbarch,
3270 struct execution_control_state *ecs);
3271 static void handle_step_into_function_backward (struct gdbarch *gdbarch,
3272 struct execution_control_state *ecs);
3273 static void handle_signal_stop (struct execution_control_state *ecs);
3274 static void check_exception_resume (struct execution_control_state *,
3275 struct frame_info *);
3276
3277 static void end_stepping_range (struct execution_control_state *ecs);
3278 static void stop_waiting (struct execution_control_state *ecs);
3279 static void keep_going (struct execution_control_state *ecs);
3280 static void process_event_stop_test (struct execution_control_state *ecs);
3281 static int switch_back_to_stepped_thread (struct execution_control_state *ecs);
3282
3283 /* This function is attached as a "thread_stop_requested" observer.
3284 Cleanup local state that assumed the PTID was to be resumed, and
3285 report the stop to the frontend. */
3286
3287 static void
3288 infrun_thread_stop_requested (ptid_t ptid)
3289 {
3290 struct thread_info *tp;
3291
3292 /* PTID was requested to stop. If the thread was already stopped,
3293 but the user/frontend doesn't know about that yet (e.g., the
3294 thread had been temporarily paused for some step-over), set up
3295 for reporting the stop now. */
3296 ALL_NON_EXITED_THREADS (tp)
3297 if (ptid_match (tp->ptid, ptid))
3298 {
3299 if (tp->state != THREAD_RUNNING)
3300 continue;
3301 if (tp->executing)
3302 continue;
3303
3304 /* Remove matching threads from the step-over queue, so
3305 start_step_over doesn't try to resume them
3306 automatically. */
3307 if (thread_is_in_step_over_chain (tp))
3308 thread_step_over_chain_remove (tp);
3309
3310 /* If the thread is stopped, but the user/frontend doesn't
3311 know about that yet, queue a pending event, as if the
3312 thread had just stopped now. Unless the thread already had
3313 a pending event. */
3314 if (!tp->suspend.waitstatus_pending_p)
3315 {
3316 tp->suspend.waitstatus_pending_p = 1;
3317 tp->suspend.waitstatus.kind = TARGET_WAITKIND_STOPPED;
3318 tp->suspend.waitstatus.value.sig = GDB_SIGNAL_0;
3319 }
3320
3321 /* Clear the inline-frame state, since we're re-processing the
3322 stop. */
3323 clear_inline_frame_state (tp->ptid);
3324
3325 /* If this thread was paused because some other thread was
3326 doing an inline-step over, let that finish first. Once
3327 that happens, we'll restart all threads and consume pending
3328 stop events then. */
3329 if (step_over_info_valid_p ())
3330 continue;
3331
3332 /* Otherwise we can process the (new) pending event now. Set
3333 it so this pending event is considered by
3334 do_target_wait. */
3335 tp->resumed = 1;
3336 }
3337 }
3338
3339 static void
3340 infrun_thread_thread_exit (struct thread_info *tp, int silent)
3341 {
3342 if (ptid_equal (target_last_wait_ptid, tp->ptid))
3343 nullify_last_target_wait_ptid ();
3344 }
3345
3346 /* Delete the step resume, single-step and longjmp/exception resume
3347 breakpoints of TP. */
3348
3349 static void
3350 delete_thread_infrun_breakpoints (struct thread_info *tp)
3351 {
3352 delete_step_resume_breakpoint (tp);
3353 delete_exception_resume_breakpoint (tp);
3354 delete_single_step_breakpoints (tp);
3355 }
3356
3357 /* If the target still has execution, call FUNC for each thread that
3358 just stopped. In all-stop, that's all the non-exited threads; in
3359 non-stop, that's the current thread, only. */
3360
3361 typedef void (*for_each_just_stopped_thread_callback_func)
3362 (struct thread_info *tp);
3363
3364 static void
3365 for_each_just_stopped_thread (for_each_just_stopped_thread_callback_func func)
3366 {
3367 if (!target_has_execution || ptid_equal (inferior_ptid, null_ptid))
3368 return;
3369
3370 if (target_is_non_stop_p ())
3371 {
3372 /* If in non-stop mode, only the current thread stopped. */
3373 func (inferior_thread ());
3374 }
3375 else
3376 {
3377 struct thread_info *tp;
3378
3379 /* In all-stop mode, all threads have stopped. */
3380 ALL_NON_EXITED_THREADS (tp)
3381 {
3382 func (tp);
3383 }
3384 }
3385 }
3386
3387 /* Delete the step resume and longjmp/exception resume breakpoints of
3388 the threads that just stopped. */
3389
3390 static void
3391 delete_just_stopped_threads_infrun_breakpoints (void)
3392 {
3393 for_each_just_stopped_thread (delete_thread_infrun_breakpoints);
3394 }
3395
3396 /* Delete the single-step breakpoints of the threads that just
3397 stopped. */
3398
3399 static void
3400 delete_just_stopped_threads_single_step_breakpoints (void)
3401 {
3402 for_each_just_stopped_thread (delete_single_step_breakpoints);
3403 }
3404
3405 /* A cleanup wrapper. */
3406
3407 static void
3408 delete_just_stopped_threads_infrun_breakpoints_cleanup (void *arg)
3409 {
3410 delete_just_stopped_threads_infrun_breakpoints ();
3411 }
3412
3413 /* See infrun.h. */
3414
3415 void
3416 print_target_wait_results (ptid_t waiton_ptid, ptid_t result_ptid,
3417 const struct target_waitstatus *ws)
3418 {
3419 std::string status_string = target_waitstatus_to_string (ws);
3420 string_file stb;
3421
3422 /* The text is split over several lines because it was getting too long.
3423 Call fprintf_unfiltered (gdb_stdlog) once so that the text is still
3424 output as a unit; we want only one timestamp printed if debug_timestamp
3425 is set. */
3426
3427 stb.printf ("infrun: target_wait (%d.%ld.%ld",
3428 ptid_get_pid (waiton_ptid),
3429 ptid_get_lwp (waiton_ptid),
3430 ptid_get_tid (waiton_ptid));
3431 if (ptid_get_pid (waiton_ptid) != -1)
3432 stb.printf (" [%s]", target_pid_to_str (waiton_ptid));
3433 stb.printf (", status) =\n");
3434 stb.printf ("infrun: %d.%ld.%ld [%s],\n",
3435 ptid_get_pid (result_ptid),
3436 ptid_get_lwp (result_ptid),
3437 ptid_get_tid (result_ptid),
3438 target_pid_to_str (result_ptid));
3439 stb.printf ("infrun: %s\n", status_string.c_str ());
3440
3441 /* This uses %s in part to handle %'s in the text, but also to avoid
3442 a gcc error: the format attribute requires a string literal. */
3443 fprintf_unfiltered (gdb_stdlog, "%s", stb.c_str ());
3444 }
3445
3446 /* Select a thread at random, out of those which are resumed and have
3447 had events. */
3448
3449 static struct thread_info *
3450 random_pending_event_thread (ptid_t waiton_ptid)
3451 {
3452 struct thread_info *event_tp;
3453 int num_events = 0;
3454 int random_selector;
3455
3456 /* First see how many events we have. Count only resumed threads
3457 that have an event pending. */
3458 ALL_NON_EXITED_THREADS (event_tp)
3459 if (ptid_match (event_tp->ptid, waiton_ptid)
3460 && event_tp->resumed
3461 && event_tp->suspend.waitstatus_pending_p)
3462 num_events++;
3463
3464 if (num_events == 0)
3465 return NULL;
3466
3467 /* Now randomly pick a thread out of those that have had events. */
3468 random_selector = (int)
3469 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
3470
3471 if (debug_infrun && num_events > 1)
3472 fprintf_unfiltered (gdb_stdlog,
3473 "infrun: Found %d events, selecting #%d\n",
3474 num_events, random_selector);
3475
3476 /* Select the Nth thread that has had an event. */
3477 ALL_NON_EXITED_THREADS (event_tp)
3478 if (ptid_match (event_tp->ptid, waiton_ptid)
3479 && event_tp->resumed
3480 && event_tp->suspend.waitstatus_pending_p)
3481 if (random_selector-- == 0)
3482 break;
3483
3484 return event_tp;
3485 }
3486
3487 /* Wrapper for target_wait that first checks whether threads have
3488 pending statuses to report before actually asking the target for
3489 more events. */
3490
3491 static ptid_t
3492 do_target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
3493 {
3494 ptid_t event_ptid;
3495 struct thread_info *tp;
3496
3497 /* First check if there is a resumed thread with a wait status
3498 pending. */
3499 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3500 {
3501 tp = random_pending_event_thread (ptid);
3502 }
3503 else
3504 {
3505 if (debug_infrun)
3506 fprintf_unfiltered (gdb_stdlog,
3507 "infrun: Waiting for specific thread %s.\n",
3508 target_pid_to_str (ptid));
3509
3510 /* We have a specific thread to check. */
3511 tp = find_thread_ptid (ptid);
3512 gdb_assert (tp != NULL);
3513 if (!tp->suspend.waitstatus_pending_p)
3514 tp = NULL;
3515 }
3516
3517 if (tp != NULL
3518 && (tp->suspend.stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3519 || tp->suspend.stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT))
3520 {
3521 struct regcache *regcache = get_thread_regcache (tp->ptid);
3522 struct gdbarch *gdbarch = regcache->arch ();
3523 CORE_ADDR pc;
3524 int discard = 0;
3525
3526 pc = regcache_read_pc (regcache);
3527
3528 if (pc != tp->suspend.stop_pc)
3529 {
3530 if (debug_infrun)
3531 fprintf_unfiltered (gdb_stdlog,
3532 "infrun: PC of %s changed. was=%s, now=%s\n",
3533 target_pid_to_str (tp->ptid),
3534 paddress (gdbarch, tp->prev_pc),
3535 paddress (gdbarch, pc));
3536 discard = 1;
3537 }
3538 else if (!breakpoint_inserted_here_p (regcache->aspace (), pc))
3539 {
3540 if (debug_infrun)
3541 fprintf_unfiltered (gdb_stdlog,
3542 "infrun: previous breakpoint of %s, at %s gone\n",
3543 target_pid_to_str (tp->ptid),
3544 paddress (gdbarch, pc));
3545
3546 discard = 1;
3547 }
3548
3549 if (discard)
3550 {
3551 if (debug_infrun)
3552 fprintf_unfiltered (gdb_stdlog,
3553 "infrun: pending event of %s cancelled.\n",
3554 target_pid_to_str (tp->ptid));
3555
3556 tp->suspend.waitstatus.kind = TARGET_WAITKIND_SPURIOUS;
3557 tp->suspend.stop_reason = TARGET_STOPPED_BY_NO_REASON;
3558 }
3559 }
3560
3561 if (tp != NULL)
3562 {
3563 if (debug_infrun)
3564 {
3565 std::string statstr
3566 = target_waitstatus_to_string (&tp->suspend.waitstatus);
3567
3568 fprintf_unfiltered (gdb_stdlog,
3569 "infrun: Using pending wait status %s for %s.\n",
3570 statstr.c_str (),
3571 target_pid_to_str (tp->ptid));
3572 }
3573
3574 /* Now that we've selected our final event LWP, un-adjust its PC
3575 if it was a software breakpoint (and the target doesn't
3576 always adjust the PC itself). */
3577 if (tp->suspend.stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3578 && !target_supports_stopped_by_sw_breakpoint ())
3579 {
3580 struct regcache *regcache;
3581 struct gdbarch *gdbarch;
3582 int decr_pc;
3583
3584 regcache = get_thread_regcache (tp->ptid);
3585 gdbarch = regcache->arch ();
3586
3587 decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3588 if (decr_pc != 0)
3589 {
3590 CORE_ADDR pc;
3591
3592 pc = regcache_read_pc (regcache);
3593 regcache_write_pc (regcache, pc + decr_pc);
3594 }
3595 }
3596
3597 tp->suspend.stop_reason = TARGET_STOPPED_BY_NO_REASON;
3598 *status = tp->suspend.waitstatus;
3599 tp->suspend.waitstatus_pending_p = 0;
3600
3601 /* Wake up the event loop again, until all pending events are
3602 processed. */
3603 if (target_is_async_p ())
3604 mark_async_event_handler (infrun_async_inferior_event_token);
3605 return tp->ptid;
3606 }
3607
3608 /* But if we don't find one, we'll have to wait. */
3609
3610 if (deprecated_target_wait_hook)
3611 event_ptid = deprecated_target_wait_hook (ptid, status, options);
3612 else
3613 event_ptid = target_wait (ptid, status, options);
3614
3615 return event_ptid;
3616 }
3617
3618 /* Prepare and stabilize the inferior for detaching it. E.g.,
3619 detaching while a thread is displaced stepping is a recipe for
3620 crashing it, as nothing would readjust the PC out of the scratch
3621 pad. */
3622
3623 void
3624 prepare_for_detach (void)
3625 {
3626 struct inferior *inf = current_inferior ();
3627 ptid_t pid_ptid = pid_to_ptid (inf->pid);
3628 struct displaced_step_inferior_state *displaced;
3629
3630 displaced = get_displaced_stepping_state (inf->pid);
3631
3632 /* Is any thread of this process displaced stepping? If not,
3633 there's nothing else to do. */
3634 if (displaced == NULL || ptid_equal (displaced->step_ptid, null_ptid))
3635 return;
3636
3637 if (debug_infrun)
3638 fprintf_unfiltered (gdb_stdlog,
3639 "displaced-stepping in-process while detaching");
3640
3641 scoped_restore restore_detaching = make_scoped_restore (&inf->detaching, true);
3642
3643 while (!ptid_equal (displaced->step_ptid, null_ptid))
3644 {
3645 struct cleanup *old_chain_2;
3646 struct execution_control_state ecss;
3647 struct execution_control_state *ecs;
3648
3649 ecs = &ecss;
3650 memset (ecs, 0, sizeof (*ecs));
3651
3652 overlay_cache_invalid = 1;
3653 /* Flush target cache before starting to handle each event.
3654 Target was running and cache could be stale. This is just a
3655 heuristic. Running threads may modify target memory, but we
3656 don't get any event. */
3657 target_dcache_invalidate ();
3658
3659 ecs->ptid = do_target_wait (pid_ptid, &ecs->ws, 0);
3660
3661 if (debug_infrun)
3662 print_target_wait_results (pid_ptid, ecs->ptid, &ecs->ws);
3663
3664 /* If an error happens while handling the event, propagate GDB's
3665 knowledge of the executing state to the frontend/user running
3666 state. */
3667 old_chain_2 = make_cleanup (finish_thread_state_cleanup,
3668 &minus_one_ptid);
3669
3670 /* Now figure out what to do with the result of the result. */
3671 handle_inferior_event (ecs);
3672
3673 /* No error, don't finish the state yet. */
3674 discard_cleanups (old_chain_2);
3675
3676 /* Breakpoints and watchpoints are not installed on the target
3677 at this point, and signals are passed directly to the
3678 inferior, so this must mean the process is gone. */
3679 if (!ecs->wait_some_more)
3680 {
3681 restore_detaching.release ();
3682 error (_("Program exited while detaching"));
3683 }
3684 }
3685
3686 restore_detaching.release ();
3687 }
3688
3689 /* Wait for control to return from inferior to debugger.
3690
3691 If inferior gets a signal, we may decide to start it up again
3692 instead of returning. That is why there is a loop in this function.
3693 When this function actually returns it means the inferior
3694 should be left stopped and GDB should read more commands. */
3695
3696 void
3697 wait_for_inferior (void)
3698 {
3699 struct cleanup *old_cleanups;
3700 struct cleanup *thread_state_chain;
3701
3702 if (debug_infrun)
3703 fprintf_unfiltered
3704 (gdb_stdlog, "infrun: wait_for_inferior ()\n");
3705
3706 old_cleanups
3707 = make_cleanup (delete_just_stopped_threads_infrun_breakpoints_cleanup,
3708 NULL);
3709
3710 /* If an error happens while handling the event, propagate GDB's
3711 knowledge of the executing state to the frontend/user running
3712 state. */
3713 thread_state_chain = make_cleanup (finish_thread_state_cleanup, &minus_one_ptid);
3714
3715 while (1)
3716 {
3717 struct execution_control_state ecss;
3718 struct execution_control_state *ecs = &ecss;
3719 ptid_t waiton_ptid = minus_one_ptid;
3720
3721 memset (ecs, 0, sizeof (*ecs));
3722
3723 overlay_cache_invalid = 1;
3724
3725 /* Flush target cache before starting to handle each event.
3726 Target was running and cache could be stale. This is just a
3727 heuristic. Running threads may modify target memory, but we
3728 don't get any event. */
3729 target_dcache_invalidate ();
3730
3731 ecs->ptid = do_target_wait (waiton_ptid, &ecs->ws, 0);
3732
3733 if (debug_infrun)
3734 print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws);
3735
3736 /* Now figure out what to do with the result of the result. */
3737 handle_inferior_event (ecs);
3738
3739 if (!ecs->wait_some_more)
3740 break;
3741 }
3742
3743 /* No error, don't finish the state yet. */
3744 discard_cleanups (thread_state_chain);
3745
3746 do_cleanups (old_cleanups);
3747 }
3748
3749 /* Cleanup that reinstalls the readline callback handler, if the
3750 target is running in the background. If while handling the target
3751 event something triggered a secondary prompt, like e.g., a
3752 pagination prompt, we'll have removed the callback handler (see
3753 gdb_readline_wrapper_line). Need to do this as we go back to the
3754 event loop, ready to process further input. Note this has no
3755 effect if the handler hasn't actually been removed, because calling
3756 rl_callback_handler_install resets the line buffer, thus losing
3757 input. */
3758
3759 static void
3760 reinstall_readline_callback_handler_cleanup (void *arg)
3761 {
3762 struct ui *ui = current_ui;
3763
3764 if (!ui->async)
3765 {
3766 /* We're not going back to the top level event loop yet. Don't
3767 install the readline callback, as it'd prep the terminal,
3768 readline-style (raw, noecho) (e.g., --batch). We'll install
3769 it the next time the prompt is displayed, when we're ready
3770 for input. */
3771 return;
3772 }
3773
3774 if (ui->command_editing && ui->prompt_state != PROMPT_BLOCKED)
3775 gdb_rl_callback_handler_reinstall ();
3776 }
3777
3778 /* Clean up the FSMs of threads that are now stopped. In non-stop,
3779 that's just the event thread. In all-stop, that's all threads. */
3780
3781 static void
3782 clean_up_just_stopped_threads_fsms (struct execution_control_state *ecs)
3783 {
3784 struct thread_info *thr = ecs->event_thread;
3785
3786 if (thr != NULL && thr->thread_fsm != NULL)
3787 thread_fsm_clean_up (thr->thread_fsm, thr);
3788
3789 if (!non_stop)
3790 {
3791 ALL_NON_EXITED_THREADS (thr)
3792 {
3793 if (thr->thread_fsm == NULL)
3794 continue;
3795 if (thr == ecs->event_thread)
3796 continue;
3797
3798 switch_to_thread (thr->ptid);
3799 thread_fsm_clean_up (thr->thread_fsm, thr);
3800 }
3801
3802 if (ecs->event_thread != NULL)
3803 switch_to_thread (ecs->event_thread->ptid);
3804 }
3805 }
3806
3807 /* Helper for all_uis_check_sync_execution_done that works on the
3808 current UI. */
3809
3810 static void
3811 check_curr_ui_sync_execution_done (void)
3812 {
3813 struct ui *ui = current_ui;
3814
3815 if (ui->prompt_state == PROMPT_NEEDED
3816 && ui->async
3817 && !gdb_in_secondary_prompt_p (ui))
3818 {
3819 target_terminal::ours ();
3820 observer_notify_sync_execution_done ();
3821 ui_register_input_event_handler (ui);
3822 }
3823 }
3824
3825 /* See infrun.h. */
3826
3827 void
3828 all_uis_check_sync_execution_done (void)
3829 {
3830 SWITCH_THRU_ALL_UIS ()
3831 {
3832 check_curr_ui_sync_execution_done ();
3833 }
3834 }
3835
3836 /* See infrun.h. */
3837
3838 void
3839 all_uis_on_sync_execution_starting (void)
3840 {
3841 SWITCH_THRU_ALL_UIS ()
3842 {
3843 if (current_ui->prompt_state == PROMPT_NEEDED)
3844 async_disable_stdin ();
3845 }
3846 }
3847
3848 /* Asynchronous version of wait_for_inferior. It is called by the
3849 event loop whenever a change of state is detected on the file
3850 descriptor corresponding to the target. It can be called more than
3851 once to complete a single execution command. In such cases we need
3852 to keep the state in a global variable ECSS. If it is the last time
3853 that this function is called for a single execution command, then
3854 report to the user that the inferior has stopped, and do the
3855 necessary cleanups. */
3856
3857 void
3858 fetch_inferior_event (void *client_data)
3859 {
3860 struct execution_control_state ecss;
3861 struct execution_control_state *ecs = &ecss;
3862 struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
3863 struct cleanup *ts_old_chain;
3864 int cmd_done = 0;
3865 ptid_t waiton_ptid = minus_one_ptid;
3866
3867 memset (ecs, 0, sizeof (*ecs));
3868
3869 /* Events are always processed with the main UI as current UI. This
3870 way, warnings, debug output, etc. are always consistently sent to
3871 the main console. */
3872 scoped_restore save_ui = make_scoped_restore (&current_ui, main_ui);
3873
3874 /* End up with readline processing input, if necessary. */
3875 make_cleanup (reinstall_readline_callback_handler_cleanup, NULL);
3876
3877 /* We're handling a live event, so make sure we're doing live
3878 debugging. If we're looking at traceframes while the target is
3879 running, we're going to need to get back to that mode after
3880 handling the event. */
3881 if (non_stop)
3882 {
3883 make_cleanup_restore_current_traceframe ();
3884 set_current_traceframe (-1);
3885 }
3886
3887 gdb::optional<scoped_restore_current_thread> maybe_restore_thread;
3888
3889 if (non_stop)
3890 /* In non-stop mode, the user/frontend should not notice a thread
3891 switch due to internal events. Make sure we reverse to the
3892 user selected thread and frame after handling the event and
3893 running any breakpoint commands. */
3894 maybe_restore_thread.emplace ();
3895
3896 overlay_cache_invalid = 1;
3897 /* Flush target cache before starting to handle each event. Target
3898 was running and cache could be stale. This is just a heuristic.
3899 Running threads may modify target memory, but we don't get any
3900 event. */
3901 target_dcache_invalidate ();
3902
3903 scoped_restore save_exec_dir
3904 = make_scoped_restore (&execution_direction, target_execution_direction ());
3905
3906 ecs->ptid = do_target_wait (waiton_ptid, &ecs->ws,
3907 target_can_async_p () ? TARGET_WNOHANG : 0);
3908
3909 if (debug_infrun)
3910 print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws);
3911
3912 /* If an error happens while handling the event, propagate GDB's
3913 knowledge of the executing state to the frontend/user running
3914 state. */
3915 if (!target_is_non_stop_p ())
3916 ts_old_chain = make_cleanup (finish_thread_state_cleanup, &minus_one_ptid);
3917 else
3918 ts_old_chain = make_cleanup (finish_thread_state_cleanup, &ecs->ptid);
3919
3920 /* Get executed before make_cleanup_restore_current_thread above to apply
3921 still for the thread which has thrown the exception. */
3922 make_bpstat_clear_actions_cleanup ();
3923
3924 make_cleanup (delete_just_stopped_threads_infrun_breakpoints_cleanup, NULL);
3925
3926 /* Now figure out what to do with the result of the result. */
3927 handle_inferior_event (ecs);
3928
3929 if (!ecs->wait_some_more)
3930 {
3931 struct inferior *inf = find_inferior_ptid (ecs->ptid);
3932 int should_stop = 1;
3933 struct thread_info *thr = ecs->event_thread;
3934 int should_notify_stop = 1;
3935
3936 delete_just_stopped_threads_infrun_breakpoints ();
3937
3938 if (thr != NULL)
3939 {
3940 struct thread_fsm *thread_fsm = thr->thread_fsm;
3941
3942 if (thread_fsm != NULL)
3943 should_stop = thread_fsm_should_stop (thread_fsm, thr);
3944 }
3945
3946 if (!should_stop)
3947 {
3948 keep_going (ecs);
3949 }
3950 else
3951 {
3952 clean_up_just_stopped_threads_fsms (ecs);
3953
3954 if (thr != NULL && thr->thread_fsm != NULL)
3955 {
3956 should_notify_stop
3957 = thread_fsm_should_notify_stop (thr->thread_fsm);
3958 }
3959
3960 if (should_notify_stop)
3961 {
3962 int proceeded = 0;
3963
3964 /* We may not find an inferior if this was a process exit. */
3965 if (inf == NULL || inf->control.stop_soon == NO_STOP_QUIETLY)
3966 proceeded = normal_stop ();
3967
3968 if (!proceeded)
3969 {
3970 inferior_event_handler (INF_EXEC_COMPLETE, NULL);
3971 cmd_done = 1;
3972 }
3973 }
3974 }
3975 }
3976
3977 /* No error, don't finish the thread states yet. */
3978 discard_cleanups (ts_old_chain);
3979
3980 /* Revert thread and frame. */
3981 do_cleanups (old_chain);
3982
3983 /* If a UI was in sync execution mode, and now isn't, restore its
3984 prompt (a synchronous execution command has finished, and we're
3985 ready for input). */
3986 all_uis_check_sync_execution_done ();
3987
3988 if (cmd_done
3989 && exec_done_display_p
3990 && (ptid_equal (inferior_ptid, null_ptid)
3991 || !is_running (inferior_ptid)))
3992 printf_unfiltered (_("completed.\n"));
3993 }
3994
3995 /* Record the frame and location we're currently stepping through. */
3996 void
3997 set_step_info (struct frame_info *frame, struct symtab_and_line sal)
3998 {
3999 struct thread_info *tp = inferior_thread ();
4000
4001 tp->control.step_frame_id = get_frame_id (frame);
4002 tp->control.step_stack_frame_id = get_stack_frame_id (frame);
4003
4004 tp->current_symtab = sal.symtab;
4005 tp->current_line = sal.line;
4006 }
4007
4008 /* Clear context switchable stepping state. */
4009
4010 void
4011 init_thread_stepping_state (struct thread_info *tss)
4012 {
4013 tss->stepped_breakpoint = 0;
4014 tss->stepping_over_breakpoint = 0;
4015 tss->stepping_over_watchpoint = 0;
4016 tss->step_after_step_resume_breakpoint = 0;
4017 }
4018
4019 /* Set the cached copy of the last ptid/waitstatus. */
4020
4021 void
4022 set_last_target_status (ptid_t ptid, struct target_waitstatus status)
4023 {
4024 target_last_wait_ptid = ptid;
4025 target_last_waitstatus = status;
4026 }
4027
4028 /* Return the cached copy of the last pid/waitstatus returned by
4029 target_wait()/deprecated_target_wait_hook(). The data is actually
4030 cached by handle_inferior_event(), which gets called immediately
4031 after target_wait()/deprecated_target_wait_hook(). */
4032
4033 void
4034 get_last_target_status (ptid_t *ptidp, struct target_waitstatus *status)
4035 {
4036 *ptidp = target_last_wait_ptid;
4037 *status = target_last_waitstatus;
4038 }
4039
4040 void
4041 nullify_last_target_wait_ptid (void)
4042 {
4043 target_last_wait_ptid = minus_one_ptid;
4044 }
4045
4046 /* Switch thread contexts. */
4047
4048 static void
4049 context_switch (ptid_t ptid)
4050 {
4051 if (debug_infrun && !ptid_equal (ptid, inferior_ptid))
4052 {
4053 fprintf_unfiltered (gdb_stdlog, "infrun: Switching context from %s ",
4054 target_pid_to_str (inferior_ptid));
4055 fprintf_unfiltered (gdb_stdlog, "to %s\n",
4056 target_pid_to_str (ptid));
4057 }
4058
4059 switch_to_thread (ptid);
4060 }
4061
4062 /* If the target can't tell whether we've hit breakpoints
4063 (target_supports_stopped_by_sw_breakpoint), and we got a SIGTRAP,
4064 check whether that could have been caused by a breakpoint. If so,
4065 adjust the PC, per gdbarch_decr_pc_after_break. */
4066
4067 static void
4068 adjust_pc_after_break (struct thread_info *thread,
4069 struct target_waitstatus *ws)
4070 {
4071 struct regcache *regcache;
4072 struct gdbarch *gdbarch;
4073 CORE_ADDR breakpoint_pc, decr_pc;
4074
4075 /* If we've hit a breakpoint, we'll normally be stopped with SIGTRAP. If
4076 we aren't, just return.
4077
4078 We assume that waitkinds other than TARGET_WAITKIND_STOPPED are not
4079 affected by gdbarch_decr_pc_after_break. Other waitkinds which are
4080 implemented by software breakpoints should be handled through the normal
4081 breakpoint layer.
4082
4083 NOTE drow/2004-01-31: On some targets, breakpoints may generate
4084 different signals (SIGILL or SIGEMT for instance), but it is less
4085 clear where the PC is pointing afterwards. It may not match
4086 gdbarch_decr_pc_after_break. I don't know any specific target that
4087 generates these signals at breakpoints (the code has been in GDB since at
4088 least 1992) so I can not guess how to handle them here.
4089
4090 In earlier versions of GDB, a target with
4091 gdbarch_have_nonsteppable_watchpoint would have the PC after hitting a
4092 watchpoint affected by gdbarch_decr_pc_after_break. I haven't found any
4093 target with both of these set in GDB history, and it seems unlikely to be
4094 correct, so gdbarch_have_nonsteppable_watchpoint is not checked here. */
4095
4096 if (ws->kind != TARGET_WAITKIND_STOPPED)
4097 return;
4098
4099 if (ws->value.sig != GDB_SIGNAL_TRAP)
4100 return;
4101
4102 /* In reverse execution, when a breakpoint is hit, the instruction
4103 under it has already been de-executed. The reported PC always
4104 points at the breakpoint address, so adjusting it further would
4105 be wrong. E.g., consider this case on a decr_pc_after_break == 1
4106 architecture:
4107
4108 B1 0x08000000 : INSN1
4109 B2 0x08000001 : INSN2
4110 0x08000002 : INSN3
4111 PC -> 0x08000003 : INSN4
4112
4113 Say you're stopped at 0x08000003 as above. Reverse continuing
4114 from that point should hit B2 as below. Reading the PC when the
4115 SIGTRAP is reported should read 0x08000001 and INSN2 should have
4116 been de-executed already.
4117
4118 B1 0x08000000 : INSN1
4119 B2 PC -> 0x08000001 : INSN2
4120 0x08000002 : INSN3
4121 0x08000003 : INSN4
4122
4123 We can't apply the same logic as for forward execution, because
4124 we would wrongly adjust the PC to 0x08000000, since there's a
4125 breakpoint at PC - 1. We'd then report a hit on B1, although
4126 INSN1 hadn't been de-executed yet. Doing nothing is the correct
4127 behaviour. */
4128 if (execution_direction == EXEC_REVERSE)
4129 return;
4130
4131 /* If the target can tell whether the thread hit a SW breakpoint,
4132 trust it. Targets that can tell also adjust the PC
4133 themselves. */
4134 if (target_supports_stopped_by_sw_breakpoint ())
4135 return;
4136
4137 /* Note that relying on whether a breakpoint is planted in memory to
4138 determine this can fail. E.g,. the breakpoint could have been
4139 removed since. Or the thread could have been told to step an
4140 instruction the size of a breakpoint instruction, and only
4141 _after_ was a breakpoint inserted at its address. */
4142
4143 /* If this target does not decrement the PC after breakpoints, then
4144 we have nothing to do. */
4145 regcache = get_thread_regcache (thread->ptid);
4146 gdbarch = regcache->arch ();
4147
4148 decr_pc = gdbarch_decr_pc_after_break (gdbarch);
4149 if (decr_pc == 0)
4150 return;
4151
4152 const address_space *aspace = regcache->aspace ();
4153
4154 /* Find the location where (if we've hit a breakpoint) the
4155 breakpoint would be. */
4156 breakpoint_pc = regcache_read_pc (regcache) - decr_pc;
4157
4158 /* If the target can't tell whether a software breakpoint triggered,
4159 fallback to figuring it out based on breakpoints we think were
4160 inserted in the target, and on whether the thread was stepped or
4161 continued. */
4162
4163 /* Check whether there actually is a software breakpoint inserted at
4164 that location.
4165
4166 If in non-stop mode, a race condition is possible where we've
4167 removed a breakpoint, but stop events for that breakpoint were
4168 already queued and arrive later. To suppress those spurious
4169 SIGTRAPs, we keep a list of such breakpoint locations for a bit,
4170 and retire them after a number of stop events are reported. Note
4171 this is an heuristic and can thus get confused. The real fix is
4172 to get the "stopped by SW BP and needs adjustment" info out of
4173 the target/kernel (and thus never reach here; see above). */
4174 if (software_breakpoint_inserted_here_p (aspace, breakpoint_pc)
4175 || (target_is_non_stop_p ()
4176 && moribund_breakpoint_here_p (aspace, breakpoint_pc)))
4177 {
4178 gdb::optional<scoped_restore_tmpl<int>> restore_operation_disable;
4179
4180 if (record_full_is_used ())
4181 restore_operation_disable.emplace
4182 (record_full_gdb_operation_disable_set ());
4183
4184 /* When using hardware single-step, a SIGTRAP is reported for both
4185 a completed single-step and a software breakpoint. Need to
4186 differentiate between the two, as the latter needs adjusting
4187 but the former does not.
4188
4189 The SIGTRAP can be due to a completed hardware single-step only if
4190 - we didn't insert software single-step breakpoints
4191 - this thread is currently being stepped
4192
4193 If any of these events did not occur, we must have stopped due
4194 to hitting a software breakpoint, and have to back up to the
4195 breakpoint address.
4196
4197 As a special case, we could have hardware single-stepped a
4198 software breakpoint. In this case (prev_pc == breakpoint_pc),
4199 we also need to back up to the breakpoint address. */
4200
4201 if (thread_has_single_step_breakpoints_set (thread)
4202 || !currently_stepping (thread)
4203 || (thread->stepped_breakpoint
4204 && thread->prev_pc == breakpoint_pc))
4205 regcache_write_pc (regcache, breakpoint_pc);
4206 }
4207 }
4208
4209 static int
4210 stepped_in_from (struct frame_info *frame, struct frame_id step_frame_id)
4211 {
4212 for (frame = get_prev_frame (frame);
4213 frame != NULL;
4214 frame = get_prev_frame (frame))
4215 {
4216 if (frame_id_eq (get_frame_id (frame), step_frame_id))
4217 return 1;
4218 if (get_frame_type (frame) != INLINE_FRAME)
4219 break;
4220 }
4221
4222 return 0;
4223 }
4224
4225 /* If the event thread has the stop requested flag set, pretend it
4226 stopped for a GDB_SIGNAL_0 (i.e., as if it stopped due to
4227 target_stop). */
4228
4229 static bool
4230 handle_stop_requested (struct execution_control_state *ecs)
4231 {
4232 if (ecs->event_thread->stop_requested)
4233 {
4234 ecs->ws.kind = TARGET_WAITKIND_STOPPED;
4235 ecs->ws.value.sig = GDB_SIGNAL_0;
4236 handle_signal_stop (ecs);
4237 return true;
4238 }
4239 return false;
4240 }
4241
4242 /* Auxiliary function that handles syscall entry/return events.
4243 It returns 1 if the inferior should keep going (and GDB
4244 should ignore the event), or 0 if the event deserves to be
4245 processed. */
4246
4247 static int
4248 handle_syscall_event (struct execution_control_state *ecs)
4249 {
4250 struct regcache *regcache;
4251 int syscall_number;
4252
4253 if (!ptid_equal (ecs->ptid, inferior_ptid))
4254 context_switch (ecs->ptid);
4255
4256 regcache = get_thread_regcache (ecs->ptid);
4257 syscall_number = ecs->ws.value.syscall_number;
4258 stop_pc = regcache_read_pc (regcache);
4259
4260 if (catch_syscall_enabled () > 0
4261 && catching_syscall_number (syscall_number) > 0)
4262 {
4263 if (debug_infrun)
4264 fprintf_unfiltered (gdb_stdlog, "infrun: syscall number = '%d'\n",
4265 syscall_number);
4266
4267 ecs->event_thread->control.stop_bpstat
4268 = bpstat_stop_status (regcache->aspace (),
4269 stop_pc, ecs->ptid, &ecs->ws);
4270
4271 if (handle_stop_requested (ecs))
4272 return 0;
4273
4274 if (bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
4275 {
4276 /* Catchpoint hit. */
4277 return 0;
4278 }
4279 }
4280
4281 if (handle_stop_requested (ecs))
4282 return 0;
4283
4284 /* If no catchpoint triggered for this, then keep going. */
4285 keep_going (ecs);
4286 return 1;
4287 }
4288
4289 /* Lazily fill in the execution_control_state's stop_func_* fields. */
4290
4291 static void
4292 fill_in_stop_func (struct gdbarch *gdbarch,
4293 struct execution_control_state *ecs)
4294 {
4295 if (!ecs->stop_func_filled_in)
4296 {
4297 /* Don't care about return value; stop_func_start and stop_func_name
4298 will both be 0 if it doesn't work. */
4299 find_pc_partial_function (stop_pc, &ecs->stop_func_name,
4300 &ecs->stop_func_start, &ecs->stop_func_end);
4301 ecs->stop_func_start
4302 += gdbarch_deprecated_function_start_offset (gdbarch);
4303
4304 if (gdbarch_skip_entrypoint_p (gdbarch))
4305 ecs->stop_func_start = gdbarch_skip_entrypoint (gdbarch,
4306 ecs->stop_func_start);
4307
4308 ecs->stop_func_filled_in = 1;
4309 }
4310 }
4311
4312
4313 /* Return the STOP_SOON field of the inferior pointed at by PTID. */
4314
4315 static enum stop_kind
4316 get_inferior_stop_soon (ptid_t ptid)
4317 {
4318 struct inferior *inf = find_inferior_ptid (ptid);
4319
4320 gdb_assert (inf != NULL);
4321 return inf->control.stop_soon;
4322 }
4323
4324 /* Wait for one event. Store the resulting waitstatus in WS, and
4325 return the event ptid. */
4326
4327 static ptid_t
4328 wait_one (struct target_waitstatus *ws)
4329 {
4330 ptid_t event_ptid;
4331 ptid_t wait_ptid = minus_one_ptid;
4332
4333 overlay_cache_invalid = 1;
4334
4335 /* Flush target cache before starting to handle each event.
4336 Target was running and cache could be stale. This is just a
4337 heuristic. Running threads may modify target memory, but we
4338 don't get any event. */
4339 target_dcache_invalidate ();
4340
4341 if (deprecated_target_wait_hook)
4342 event_ptid = deprecated_target_wait_hook (wait_ptid, ws, 0);
4343 else
4344 event_ptid = target_wait (wait_ptid, ws, 0);
4345
4346 if (debug_infrun)
4347 print_target_wait_results (wait_ptid, event_ptid, ws);
4348
4349 return event_ptid;
4350 }
4351
4352 /* Generate a wrapper for target_stopped_by_REASON that works on PTID
4353 instead of the current thread. */
4354 #define THREAD_STOPPED_BY(REASON) \
4355 static int \
4356 thread_stopped_by_ ## REASON (ptid_t ptid) \
4357 { \
4358 scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid); \
4359 inferior_ptid = ptid; \
4360 \
4361 return target_stopped_by_ ## REASON (); \
4362 }
4363
4364 /* Generate thread_stopped_by_watchpoint. */
4365 THREAD_STOPPED_BY (watchpoint)
4366 /* Generate thread_stopped_by_sw_breakpoint. */
4367 THREAD_STOPPED_BY (sw_breakpoint)
4368 /* Generate thread_stopped_by_hw_breakpoint. */
4369 THREAD_STOPPED_BY (hw_breakpoint)
4370
4371 /* Cleanups that switches to the PTID pointed at by PTID_P. */
4372
4373 static void
4374 switch_to_thread_cleanup (void *ptid_p)
4375 {
4376 ptid_t ptid = *(ptid_t *) ptid_p;
4377
4378 switch_to_thread (ptid);
4379 }
4380
4381 /* Save the thread's event and stop reason to process it later. */
4382
4383 static void
4384 save_waitstatus (struct thread_info *tp, struct target_waitstatus *ws)
4385 {
4386 struct regcache *regcache;
4387
4388 if (debug_infrun)
4389 {
4390 std::string statstr = target_waitstatus_to_string (ws);
4391
4392 fprintf_unfiltered (gdb_stdlog,
4393 "infrun: saving status %s for %d.%ld.%ld\n",
4394 statstr.c_str (),
4395 ptid_get_pid (tp->ptid),
4396 ptid_get_lwp (tp->ptid),
4397 ptid_get_tid (tp->ptid));
4398 }
4399
4400 /* Record for later. */
4401 tp->suspend.waitstatus = *ws;
4402 tp->suspend.waitstatus_pending_p = 1;
4403
4404 regcache = get_thread_regcache (tp->ptid);
4405 const address_space *aspace = regcache->aspace ();
4406
4407 if (ws->kind == TARGET_WAITKIND_STOPPED
4408 && ws->value.sig == GDB_SIGNAL_TRAP)
4409 {
4410 CORE_ADDR pc = regcache_read_pc (regcache);
4411
4412 adjust_pc_after_break (tp, &tp->suspend.waitstatus);
4413
4414 if (thread_stopped_by_watchpoint (tp->ptid))
4415 {
4416 tp->suspend.stop_reason
4417 = TARGET_STOPPED_BY_WATCHPOINT;
4418 }
4419 else if (target_supports_stopped_by_sw_breakpoint ()
4420 && thread_stopped_by_sw_breakpoint (tp->ptid))
4421 {
4422 tp->suspend.stop_reason
4423 = TARGET_STOPPED_BY_SW_BREAKPOINT;
4424 }
4425 else if (target_supports_stopped_by_hw_breakpoint ()
4426 && thread_stopped_by_hw_breakpoint (tp->ptid))
4427 {
4428 tp->suspend.stop_reason
4429 = TARGET_STOPPED_BY_HW_BREAKPOINT;
4430 }
4431 else if (!target_supports_stopped_by_hw_breakpoint ()
4432 && hardware_breakpoint_inserted_here_p (aspace,
4433 pc))
4434 {
4435 tp->suspend.stop_reason
4436 = TARGET_STOPPED_BY_HW_BREAKPOINT;
4437 }
4438 else if (!target_supports_stopped_by_sw_breakpoint ()
4439 && software_breakpoint_inserted_here_p (aspace,
4440 pc))
4441 {
4442 tp->suspend.stop_reason
4443 = TARGET_STOPPED_BY_SW_BREAKPOINT;
4444 }
4445 else if (!thread_has_single_step_breakpoints_set (tp)
4446 && currently_stepping (tp))
4447 {
4448 tp->suspend.stop_reason
4449 = TARGET_STOPPED_BY_SINGLE_STEP;
4450 }
4451 }
4452 }
4453
4454 /* A cleanup that disables thread create/exit events. */
4455
4456 static void
4457 disable_thread_events (void *arg)
4458 {
4459 target_thread_events (0);
4460 }
4461
4462 /* See infrun.h. */
4463
4464 void
4465 stop_all_threads (void)
4466 {
4467 /* We may need multiple passes to discover all threads. */
4468 int pass;
4469 int iterations = 0;
4470 ptid_t entry_ptid;
4471 struct cleanup *old_chain;
4472
4473 gdb_assert (target_is_non_stop_p ());
4474
4475 if (debug_infrun)
4476 fprintf_unfiltered (gdb_stdlog, "infrun: stop_all_threads\n");
4477
4478 entry_ptid = inferior_ptid;
4479 old_chain = make_cleanup (switch_to_thread_cleanup, &entry_ptid);
4480
4481 target_thread_events (1);
4482 make_cleanup (disable_thread_events, NULL);
4483
4484 /* Request threads to stop, and then wait for the stops. Because
4485 threads we already know about can spawn more threads while we're
4486 trying to stop them, and we only learn about new threads when we
4487 update the thread list, do this in a loop, and keep iterating
4488 until two passes find no threads that need to be stopped. */
4489 for (pass = 0; pass < 2; pass++, iterations++)
4490 {
4491 if (debug_infrun)
4492 fprintf_unfiltered (gdb_stdlog,
4493 "infrun: stop_all_threads, pass=%d, "
4494 "iterations=%d\n", pass, iterations);
4495 while (1)
4496 {
4497 ptid_t event_ptid;
4498 struct target_waitstatus ws;
4499 int need_wait = 0;
4500 struct thread_info *t;
4501
4502 update_thread_list ();
4503
4504 /* Go through all threads looking for threads that we need
4505 to tell the target to stop. */
4506 ALL_NON_EXITED_THREADS (t)
4507 {
4508 if (t->executing)
4509 {
4510 /* If already stopping, don't request a stop again.
4511 We just haven't seen the notification yet. */
4512 if (!t->stop_requested)
4513 {
4514 if (debug_infrun)
4515 fprintf_unfiltered (gdb_stdlog,
4516 "infrun: %s executing, "
4517 "need stop\n",
4518 target_pid_to_str (t->ptid));
4519 target_stop (t->ptid);
4520 t->stop_requested = 1;
4521 }
4522 else
4523 {
4524 if (debug_infrun)
4525 fprintf_unfiltered (gdb_stdlog,
4526 "infrun: %s executing, "
4527 "already stopping\n",
4528 target_pid_to_str (t->ptid));
4529 }
4530
4531 if (t->stop_requested)
4532 need_wait = 1;
4533 }
4534 else
4535 {
4536 if (debug_infrun)
4537 fprintf_unfiltered (gdb_stdlog,
4538 "infrun: %s not executing\n",
4539 target_pid_to_str (t->ptid));
4540
4541 /* The thread may be not executing, but still be
4542 resumed with a pending status to process. */
4543 t->resumed = 0;
4544 }
4545 }
4546
4547 if (!need_wait)
4548 break;
4549
4550 /* If we find new threads on the second iteration, restart
4551 over. We want to see two iterations in a row with all
4552 threads stopped. */
4553 if (pass > 0)
4554 pass = -1;
4555
4556 event_ptid = wait_one (&ws);
4557 if (ws.kind == TARGET_WAITKIND_NO_RESUMED)
4558 {
4559 /* All resumed threads exited. */
4560 }
4561 else if (ws.kind == TARGET_WAITKIND_THREAD_EXITED
4562 || ws.kind == TARGET_WAITKIND_EXITED
4563 || ws.kind == TARGET_WAITKIND_SIGNALLED)
4564 {
4565 if (debug_infrun)
4566 {
4567 ptid_t ptid = pid_to_ptid (ws.value.integer);
4568
4569 fprintf_unfiltered (gdb_stdlog,
4570 "infrun: %s exited while "
4571 "stopping threads\n",
4572 target_pid_to_str (ptid));
4573 }
4574 }
4575 else
4576 {
4577 struct inferior *inf;
4578
4579 t = find_thread_ptid (event_ptid);
4580 if (t == NULL)
4581 t = add_thread (event_ptid);
4582
4583 t->stop_requested = 0;
4584 t->executing = 0;
4585 t->resumed = 0;
4586 t->control.may_range_step = 0;
4587
4588 /* This may be the first time we see the inferior report
4589 a stop. */
4590 inf = find_inferior_ptid (event_ptid);
4591 if (inf->needs_setup)
4592 {
4593 switch_to_thread_no_regs (t);
4594 setup_inferior (0);
4595 }
4596
4597 if (ws.kind == TARGET_WAITKIND_STOPPED
4598 && ws.value.sig == GDB_SIGNAL_0)
4599 {
4600 /* We caught the event that we intended to catch, so
4601 there's no event pending. */
4602 t->suspend.waitstatus.kind = TARGET_WAITKIND_IGNORE;
4603 t->suspend.waitstatus_pending_p = 0;
4604
4605 if (displaced_step_fixup (t->ptid, GDB_SIGNAL_0) < 0)
4606 {
4607 /* Add it back to the step-over queue. */
4608 if (debug_infrun)
4609 {
4610 fprintf_unfiltered (gdb_stdlog,
4611 "infrun: displaced-step of %s "
4612 "canceled: adding back to the "
4613 "step-over queue\n",
4614 target_pid_to_str (t->ptid));
4615 }
4616 t->control.trap_expected = 0;
4617 thread_step_over_chain_enqueue (t);
4618 }
4619 }
4620 else
4621 {
4622 enum gdb_signal sig;
4623 struct regcache *regcache;
4624
4625 if (debug_infrun)
4626 {
4627 std::string statstr = target_waitstatus_to_string (&ws);
4628
4629 fprintf_unfiltered (gdb_stdlog,
4630 "infrun: target_wait %s, saving "
4631 "status for %d.%ld.%ld\n",
4632 statstr.c_str (),
4633 ptid_get_pid (t->ptid),
4634 ptid_get_lwp (t->ptid),
4635 ptid_get_tid (t->ptid));
4636 }
4637
4638 /* Record for later. */
4639 save_waitstatus (t, &ws);
4640
4641 sig = (ws.kind == TARGET_WAITKIND_STOPPED
4642 ? ws.value.sig : GDB_SIGNAL_0);
4643
4644 if (displaced_step_fixup (t->ptid, sig) < 0)
4645 {
4646 /* Add it back to the step-over queue. */
4647 t->control.trap_expected = 0;
4648 thread_step_over_chain_enqueue (t);
4649 }
4650
4651 regcache = get_thread_regcache (t->ptid);
4652 t->suspend.stop_pc = regcache_read_pc (regcache);
4653
4654 if (debug_infrun)
4655 {
4656 fprintf_unfiltered (gdb_stdlog,
4657 "infrun: saved stop_pc=%s for %s "
4658 "(currently_stepping=%d)\n",
4659 paddress (target_gdbarch (),
4660 t->suspend.stop_pc),
4661 target_pid_to_str (t->ptid),
4662 currently_stepping (t));
4663 }
4664 }
4665 }
4666 }
4667 }
4668
4669 do_cleanups (old_chain);
4670
4671 if (debug_infrun)
4672 fprintf_unfiltered (gdb_stdlog, "infrun: stop_all_threads done\n");
4673 }
4674
4675 /* Handle a TARGET_WAITKIND_NO_RESUMED event. */
4676
4677 static int
4678 handle_no_resumed (struct execution_control_state *ecs)
4679 {
4680 struct inferior *inf;
4681 struct thread_info *thread;
4682
4683 if (target_can_async_p ())
4684 {
4685 struct ui *ui;
4686 int any_sync = 0;
4687
4688 ALL_UIS (ui)
4689 {
4690 if (ui->prompt_state == PROMPT_BLOCKED)
4691 {
4692 any_sync = 1;
4693 break;
4694 }
4695 }
4696 if (!any_sync)
4697 {
4698 /* There were no unwaited-for children left in the target, but,
4699 we're not synchronously waiting for events either. Just
4700 ignore. */
4701
4702 if (debug_infrun)
4703 fprintf_unfiltered (gdb_stdlog,
4704 "infrun: TARGET_WAITKIND_NO_RESUMED "
4705 "(ignoring: bg)\n");
4706 prepare_to_wait (ecs);
4707 return 1;
4708 }
4709 }
4710
4711 /* Otherwise, if we were running a synchronous execution command, we
4712 may need to cancel it and give the user back the terminal.
4713
4714 In non-stop mode, the target can't tell whether we've already
4715 consumed previous stop events, so it can end up sending us a
4716 no-resumed event like so:
4717
4718 #0 - thread 1 is left stopped
4719
4720 #1 - thread 2 is resumed and hits breakpoint
4721 -> TARGET_WAITKIND_STOPPED
4722
4723 #2 - thread 3 is resumed and exits
4724 this is the last resumed thread, so
4725 -> TARGET_WAITKIND_NO_RESUMED
4726
4727 #3 - gdb processes stop for thread 2 and decides to re-resume
4728 it.
4729
4730 #4 - gdb processes the TARGET_WAITKIND_NO_RESUMED event.
4731 thread 2 is now resumed, so the event should be ignored.
4732
4733 IOW, if the stop for thread 2 doesn't end a foreground command,
4734 then we need to ignore the following TARGET_WAITKIND_NO_RESUMED
4735 event. But it could be that the event meant that thread 2 itself
4736 (or whatever other thread was the last resumed thread) exited.
4737
4738 To address this we refresh the thread list and check whether we
4739 have resumed threads _now_. In the example above, this removes
4740 thread 3 from the thread list. If thread 2 was re-resumed, we
4741 ignore this event. If we find no thread resumed, then we cancel
4742 the synchronous command show "no unwaited-for " to the user. */
4743 update_thread_list ();
4744
4745 ALL_NON_EXITED_THREADS (thread)
4746 {
4747 if (thread->executing
4748 || thread->suspend.waitstatus_pending_p)
4749 {
4750 /* There were no unwaited-for children left in the target at
4751 some point, but there are now. Just ignore. */
4752 if (debug_infrun)
4753 fprintf_unfiltered (gdb_stdlog,
4754 "infrun: TARGET_WAITKIND_NO_RESUMED "
4755 "(ignoring: found resumed)\n");
4756 prepare_to_wait (ecs);
4757 return 1;
4758 }
4759 }
4760
4761 /* Note however that we may find no resumed thread because the whole
4762 process exited meanwhile (thus updating the thread list results
4763 in an empty thread list). In this case we know we'll be getting
4764 a process exit event shortly. */
4765 ALL_INFERIORS (inf)
4766 {
4767 if (inf->pid == 0)
4768 continue;
4769
4770 thread = any_live_thread_of_process (inf->pid);
4771 if (thread == NULL)
4772 {
4773 if (debug_infrun)
4774 fprintf_unfiltered (gdb_stdlog,
4775 "infrun: TARGET_WAITKIND_NO_RESUMED "
4776 "(expect process exit)\n");
4777 prepare_to_wait (ecs);
4778 return 1;
4779 }
4780 }
4781
4782 /* Go ahead and report the event. */
4783 return 0;
4784 }
4785
4786 /* Given an execution control state that has been freshly filled in by
4787 an event from the inferior, figure out what it means and take
4788 appropriate action.
4789
4790 The alternatives are:
4791
4792 1) stop_waiting and return; to really stop and return to the
4793 debugger.
4794
4795 2) keep_going and return; to wait for the next event (set
4796 ecs->event_thread->stepping_over_breakpoint to 1 to single step
4797 once). */
4798
4799 static void
4800 handle_inferior_event_1 (struct execution_control_state *ecs)
4801 {
4802 enum stop_kind stop_soon;
4803
4804 if (ecs->ws.kind == TARGET_WAITKIND_IGNORE)
4805 {
4806 /* We had an event in the inferior, but we are not interested in
4807 handling it at this level. The lower layers have already
4808 done what needs to be done, if anything.
4809
4810 One of the possible circumstances for this is when the
4811 inferior produces output for the console. The inferior has
4812 not stopped, and we are ignoring the event. Another possible
4813 circumstance is any event which the lower level knows will be
4814 reported multiple times without an intervening resume. */
4815 if (debug_infrun)
4816 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_IGNORE\n");
4817 prepare_to_wait (ecs);
4818 return;
4819 }
4820
4821 if (ecs->ws.kind == TARGET_WAITKIND_THREAD_EXITED)
4822 {
4823 if (debug_infrun)
4824 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_THREAD_EXITED\n");
4825 prepare_to_wait (ecs);
4826 return;
4827 }
4828
4829 if (ecs->ws.kind == TARGET_WAITKIND_NO_RESUMED
4830 && handle_no_resumed (ecs))
4831 return;
4832
4833 /* Cache the last pid/waitstatus. */
4834 set_last_target_status (ecs->ptid, ecs->ws);
4835
4836 /* Always clear state belonging to the previous time we stopped. */
4837 stop_stack_dummy = STOP_NONE;
4838
4839 if (ecs->ws.kind == TARGET_WAITKIND_NO_RESUMED)
4840 {
4841 /* No unwaited-for children left. IOW, all resumed children
4842 have exited. */
4843 if (debug_infrun)
4844 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_NO_RESUMED\n");
4845
4846 stop_print_frame = 0;
4847 stop_waiting (ecs);
4848 return;
4849 }
4850
4851 if (ecs->ws.kind != TARGET_WAITKIND_EXITED
4852 && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED)
4853 {
4854 ecs->event_thread = find_thread_ptid (ecs->ptid);
4855 /* If it's a new thread, add it to the thread database. */
4856 if (ecs->event_thread == NULL)
4857 ecs->event_thread = add_thread (ecs->ptid);
4858
4859 /* Disable range stepping. If the next step request could use a
4860 range, this will be end up re-enabled then. */
4861 ecs->event_thread->control.may_range_step = 0;
4862 }
4863
4864 /* Dependent on valid ECS->EVENT_THREAD. */
4865 adjust_pc_after_break (ecs->event_thread, &ecs->ws);
4866
4867 /* Dependent on the current PC value modified by adjust_pc_after_break. */
4868 reinit_frame_cache ();
4869
4870 breakpoint_retire_moribund ();
4871
4872 /* First, distinguish signals caused by the debugger from signals
4873 that have to do with the program's own actions. Note that
4874 breakpoint insns may cause SIGTRAP or SIGILL or SIGEMT, depending
4875 on the operating system version. Here we detect when a SIGILL or
4876 SIGEMT is really a breakpoint and change it to SIGTRAP. We do
4877 something similar for SIGSEGV, since a SIGSEGV will be generated
4878 when we're trying to execute a breakpoint instruction on a
4879 non-executable stack. This happens for call dummy breakpoints
4880 for architectures like SPARC that place call dummies on the
4881 stack. */
4882 if (ecs->ws.kind == TARGET_WAITKIND_STOPPED
4883 && (ecs->ws.value.sig == GDB_SIGNAL_ILL
4884 || ecs->ws.value.sig == GDB_SIGNAL_SEGV
4885 || ecs->ws.value.sig == GDB_SIGNAL_EMT))
4886 {
4887 struct regcache *regcache = get_thread_regcache (ecs->ptid);
4888
4889 if (breakpoint_inserted_here_p (regcache->aspace (),
4890 regcache_read_pc (regcache)))
4891 {
4892 if (debug_infrun)
4893 fprintf_unfiltered (gdb_stdlog,
4894 "infrun: Treating signal as SIGTRAP\n");
4895 ecs->ws.value.sig = GDB_SIGNAL_TRAP;
4896 }
4897 }
4898
4899 /* Mark the non-executing threads accordingly. In all-stop, all
4900 threads of all processes are stopped when we get any event
4901 reported. In non-stop mode, only the event thread stops. */
4902 {
4903 ptid_t mark_ptid;
4904
4905 if (!target_is_non_stop_p ())
4906 mark_ptid = minus_one_ptid;
4907 else if (ecs->ws.kind == TARGET_WAITKIND_SIGNALLED
4908 || ecs->ws.kind == TARGET_WAITKIND_EXITED)
4909 {
4910 /* If we're handling a process exit in non-stop mode, even
4911 though threads haven't been deleted yet, one would think
4912 that there is nothing to do, as threads of the dead process
4913 will be soon deleted, and threads of any other process were
4914 left running. However, on some targets, threads survive a
4915 process exit event. E.g., for the "checkpoint" command,
4916 when the current checkpoint/fork exits, linux-fork.c
4917 automatically switches to another fork from within
4918 target_mourn_inferior, by associating the same
4919 inferior/thread to another fork. We haven't mourned yet at
4920 this point, but we must mark any threads left in the
4921 process as not-executing so that finish_thread_state marks
4922 them stopped (in the user's perspective) if/when we present
4923 the stop to the user. */
4924 mark_ptid = pid_to_ptid (ptid_get_pid (ecs->ptid));
4925 }
4926 else
4927 mark_ptid = ecs->ptid;
4928
4929 set_executing (mark_ptid, 0);
4930
4931 /* Likewise the resumed flag. */
4932 set_resumed (mark_ptid, 0);
4933 }
4934
4935 switch (ecs->ws.kind)
4936 {
4937 case TARGET_WAITKIND_LOADED:
4938 if (debug_infrun)
4939 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_LOADED\n");
4940 if (!ptid_equal (ecs->ptid, inferior_ptid))
4941 context_switch (ecs->ptid);
4942 /* Ignore gracefully during startup of the inferior, as it might
4943 be the shell which has just loaded some objects, otherwise
4944 add the symbols for the newly loaded objects. Also ignore at
4945 the beginning of an attach or remote session; we will query
4946 the full list of libraries once the connection is
4947 established. */
4948
4949 stop_soon = get_inferior_stop_soon (ecs->ptid);
4950 if (stop_soon == NO_STOP_QUIETLY)
4951 {
4952 struct regcache *regcache;
4953
4954 regcache = get_thread_regcache (ecs->ptid);
4955
4956 handle_solib_event ();
4957
4958 ecs->event_thread->control.stop_bpstat
4959 = bpstat_stop_status (regcache->aspace (),
4960 stop_pc, ecs->ptid, &ecs->ws);
4961
4962 if (handle_stop_requested (ecs))
4963 return;
4964
4965 if (bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
4966 {
4967 /* A catchpoint triggered. */
4968 process_event_stop_test (ecs);
4969 return;
4970 }
4971
4972 /* If requested, stop when the dynamic linker notifies
4973 gdb of events. This allows the user to get control
4974 and place breakpoints in initializer routines for
4975 dynamically loaded objects (among other things). */
4976 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
4977 if (stop_on_solib_events)
4978 {
4979 /* Make sure we print "Stopped due to solib-event" in
4980 normal_stop. */
4981 stop_print_frame = 1;
4982
4983 stop_waiting (ecs);
4984 return;
4985 }
4986 }
4987
4988 /* If we are skipping through a shell, or through shared library
4989 loading that we aren't interested in, resume the program. If
4990 we're running the program normally, also resume. */
4991 if (stop_soon == STOP_QUIETLY || stop_soon == NO_STOP_QUIETLY)
4992 {
4993 /* Loading of shared libraries might have changed breakpoint
4994 addresses. Make sure new breakpoints are inserted. */
4995 if (stop_soon == NO_STOP_QUIETLY)
4996 insert_breakpoints ();
4997 resume (GDB_SIGNAL_0);
4998 prepare_to_wait (ecs);
4999 return;
5000 }
5001
5002 /* But stop if we're attaching or setting up a remote
5003 connection. */
5004 if (stop_soon == STOP_QUIETLY_NO_SIGSTOP
5005 || stop_soon == STOP_QUIETLY_REMOTE)
5006 {
5007 if (debug_infrun)
5008 fprintf_unfiltered (gdb_stdlog, "infrun: quietly stopped\n");
5009 stop_waiting (ecs);
5010 return;
5011 }
5012
5013 internal_error (__FILE__, __LINE__,
5014 _("unhandled stop_soon: %d"), (int) stop_soon);
5015
5016 case TARGET_WAITKIND_SPURIOUS:
5017 if (debug_infrun)
5018 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_SPURIOUS\n");
5019 if (handle_stop_requested (ecs))
5020 return;
5021 if (!ptid_equal (ecs->ptid, inferior_ptid))
5022 context_switch (ecs->ptid);
5023 resume (GDB_SIGNAL_0);
5024 prepare_to_wait (ecs);
5025 return;
5026
5027 case TARGET_WAITKIND_THREAD_CREATED:
5028 if (debug_infrun)
5029 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_THREAD_CREATED\n");
5030 if (handle_stop_requested (ecs))
5031 return;
5032 if (!ptid_equal (ecs->ptid, inferior_ptid))
5033 context_switch (ecs->ptid);
5034 if (!switch_back_to_stepped_thread (ecs))
5035 keep_going (ecs);
5036 return;
5037
5038 case TARGET_WAITKIND_EXITED:
5039 case TARGET_WAITKIND_SIGNALLED:
5040 if (debug_infrun)
5041 {
5042 if (ecs->ws.kind == TARGET_WAITKIND_EXITED)
5043 fprintf_unfiltered (gdb_stdlog,
5044 "infrun: TARGET_WAITKIND_EXITED\n");
5045 else
5046 fprintf_unfiltered (gdb_stdlog,
5047 "infrun: TARGET_WAITKIND_SIGNALLED\n");
5048 }
5049
5050 inferior_ptid = ecs->ptid;
5051 set_current_inferior (find_inferior_ptid (ecs->ptid));
5052 set_current_program_space (current_inferior ()->pspace);
5053 handle_vfork_child_exec_or_exit (0);
5054 target_terminal::ours (); /* Must do this before mourn anyway. */
5055
5056 /* Clearing any previous state of convenience variables. */
5057 clear_exit_convenience_vars ();
5058
5059 if (ecs->ws.kind == TARGET_WAITKIND_EXITED)
5060 {
5061 /* Record the exit code in the convenience variable $_exitcode, so
5062 that the user can inspect this again later. */
5063 set_internalvar_integer (lookup_internalvar ("_exitcode"),
5064 (LONGEST) ecs->ws.value.integer);
5065
5066 /* Also record this in the inferior itself. */
5067 current_inferior ()->has_exit_code = 1;
5068 current_inferior ()->exit_code = (LONGEST) ecs->ws.value.integer;
5069
5070 /* Support the --return-child-result option. */
5071 return_child_result_value = ecs->ws.value.integer;
5072
5073 observer_notify_exited (ecs->ws.value.integer);
5074 }
5075 else
5076 {
5077 struct regcache *regcache = get_thread_regcache (ecs->ptid);
5078 struct gdbarch *gdbarch = regcache->arch ();
5079
5080 if (gdbarch_gdb_signal_to_target_p (gdbarch))
5081 {
5082 /* Set the value of the internal variable $_exitsignal,
5083 which holds the signal uncaught by the inferior. */
5084 set_internalvar_integer (lookup_internalvar ("_exitsignal"),
5085 gdbarch_gdb_signal_to_target (gdbarch,
5086 ecs->ws.value.sig));
5087 }
5088 else
5089 {
5090 /* We don't have access to the target's method used for
5091 converting between signal numbers (GDB's internal
5092 representation <-> target's representation).
5093 Therefore, we cannot do a good job at displaying this
5094 information to the user. It's better to just warn
5095 her about it (if infrun debugging is enabled), and
5096 give up. */
5097 if (debug_infrun)
5098 fprintf_filtered (gdb_stdlog, _("\
5099 Cannot fill $_exitsignal with the correct signal number.\n"));
5100 }
5101
5102 observer_notify_signal_exited (ecs->ws.value.sig);
5103 }
5104
5105 gdb_flush (gdb_stdout);
5106 target_mourn_inferior (inferior_ptid);
5107 stop_print_frame = 0;
5108 stop_waiting (ecs);
5109 return;
5110
5111 /* The following are the only cases in which we keep going;
5112 the above cases end in a continue or goto. */
5113 case TARGET_WAITKIND_FORKED:
5114 case TARGET_WAITKIND_VFORKED:
5115 if (debug_infrun)
5116 {
5117 if (ecs->ws.kind == TARGET_WAITKIND_FORKED)
5118 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_FORKED\n");
5119 else
5120 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_VFORKED\n");
5121 }
5122
5123 /* Check whether the inferior is displaced stepping. */
5124 {
5125 struct regcache *regcache = get_thread_regcache (ecs->ptid);
5126 struct gdbarch *gdbarch = regcache->arch ();
5127
5128 /* If checking displaced stepping is supported, and thread
5129 ecs->ptid is displaced stepping. */
5130 if (displaced_step_in_progress_thread (ecs->ptid))
5131 {
5132 struct inferior *parent_inf
5133 = find_inferior_ptid (ecs->ptid);
5134 struct regcache *child_regcache;
5135 CORE_ADDR parent_pc;
5136
5137 /* GDB has got TARGET_WAITKIND_FORKED or TARGET_WAITKIND_VFORKED,
5138 indicating that the displaced stepping of syscall instruction
5139 has been done. Perform cleanup for parent process here. Note
5140 that this operation also cleans up the child process for vfork,
5141 because their pages are shared. */
5142 displaced_step_fixup (ecs->ptid, GDB_SIGNAL_TRAP);
5143 /* Start a new step-over in another thread if there's one
5144 that needs it. */
5145 start_step_over ();
5146
5147 if (ecs->ws.kind == TARGET_WAITKIND_FORKED)
5148 {
5149 struct displaced_step_inferior_state *displaced
5150 = get_displaced_stepping_state (ptid_get_pid (ecs->ptid));
5151
5152 /* Restore scratch pad for child process. */
5153 displaced_step_restore (displaced, ecs->ws.value.related_pid);
5154 }
5155
5156 /* Since the vfork/fork syscall instruction was executed in the scratchpad,
5157 the child's PC is also within the scratchpad. Set the child's PC
5158 to the parent's PC value, which has already been fixed up.
5159 FIXME: we use the parent's aspace here, although we're touching
5160 the child, because the child hasn't been added to the inferior
5161 list yet at this point. */
5162
5163 child_regcache
5164 = get_thread_arch_aspace_regcache (ecs->ws.value.related_pid,
5165 gdbarch,
5166 parent_inf->aspace);
5167 /* Read PC value of parent process. */
5168 parent_pc = regcache_read_pc (regcache);
5169
5170 if (debug_displaced)
5171 fprintf_unfiltered (gdb_stdlog,
5172 "displaced: write child pc from %s to %s\n",
5173 paddress (gdbarch,
5174 regcache_read_pc (child_regcache)),
5175 paddress (gdbarch, parent_pc));
5176
5177 regcache_write_pc (child_regcache, parent_pc);
5178 }
5179 }
5180
5181 if (!ptid_equal (ecs->ptid, inferior_ptid))
5182 context_switch (ecs->ptid);
5183
5184 /* Immediately detach breakpoints from the child before there's
5185 any chance of letting the user delete breakpoints from the
5186 breakpoint lists. If we don't do this early, it's easy to
5187 leave left over traps in the child, vis: "break foo; catch
5188 fork; c; <fork>; del; c; <child calls foo>". We only follow
5189 the fork on the last `continue', and by that time the
5190 breakpoint at "foo" is long gone from the breakpoint table.
5191 If we vforked, then we don't need to unpatch here, since both
5192 parent and child are sharing the same memory pages; we'll
5193 need to unpatch at follow/detach time instead to be certain
5194 that new breakpoints added between catchpoint hit time and
5195 vfork follow are detached. */
5196 if (ecs->ws.kind != TARGET_WAITKIND_VFORKED)
5197 {
5198 /* This won't actually modify the breakpoint list, but will
5199 physically remove the breakpoints from the child. */
5200 detach_breakpoints (ecs->ws.value.related_pid);
5201 }
5202
5203 delete_just_stopped_threads_single_step_breakpoints ();
5204
5205 /* In case the event is caught by a catchpoint, remember that
5206 the event is to be followed at the next resume of the thread,
5207 and not immediately. */
5208 ecs->event_thread->pending_follow = ecs->ws;
5209
5210 stop_pc = regcache_read_pc (get_thread_regcache (ecs->ptid));
5211
5212 ecs->event_thread->control.stop_bpstat
5213 = bpstat_stop_status (get_current_regcache ()->aspace (),
5214 stop_pc, ecs->ptid, &ecs->ws);
5215
5216 if (handle_stop_requested (ecs))
5217 return;
5218
5219 /* If no catchpoint triggered for this, then keep going. Note
5220 that we're interested in knowing the bpstat actually causes a
5221 stop, not just if it may explain the signal. Software
5222 watchpoints, for example, always appear in the bpstat. */
5223 if (!bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
5224 {
5225 ptid_t parent;
5226 ptid_t child;
5227 int should_resume;
5228 int follow_child
5229 = (follow_fork_mode_string == follow_fork_mode_child);
5230
5231 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
5232
5233 should_resume = follow_fork ();
5234
5235 parent = ecs->ptid;
5236 child = ecs->ws.value.related_pid;
5237
5238 /* At this point, the parent is marked running, and the
5239 child is marked stopped. */
5240
5241 /* If not resuming the parent, mark it stopped. */
5242 if (follow_child && !detach_fork && !non_stop && !sched_multi)
5243 set_running (parent, 0);
5244
5245 /* If resuming the child, mark it running. */
5246 if (follow_child || (!detach_fork && (non_stop || sched_multi)))
5247 set_running (child, 1);
5248
5249 /* In non-stop mode, also resume the other branch. */
5250 if (!detach_fork && (non_stop
5251 || (sched_multi && target_is_non_stop_p ())))
5252 {
5253 if (follow_child)
5254 switch_to_thread (parent);
5255 else
5256 switch_to_thread (child);
5257
5258 ecs->event_thread = inferior_thread ();
5259 ecs->ptid = inferior_ptid;
5260 keep_going (ecs);
5261 }
5262
5263 if (follow_child)
5264 switch_to_thread (child);
5265 else
5266 switch_to_thread (parent);
5267
5268 ecs->event_thread = inferior_thread ();
5269 ecs->ptid = inferior_ptid;
5270
5271 if (should_resume)
5272 keep_going (ecs);
5273 else
5274 stop_waiting (ecs);
5275 return;
5276 }
5277 process_event_stop_test (ecs);
5278 return;
5279
5280 case TARGET_WAITKIND_VFORK_DONE:
5281 /* Done with the shared memory region. Re-insert breakpoints in
5282 the parent, and keep going. */
5283
5284 if (debug_infrun)
5285 fprintf_unfiltered (gdb_stdlog,
5286 "infrun: TARGET_WAITKIND_VFORK_DONE\n");
5287
5288 if (!ptid_equal (ecs->ptid, inferior_ptid))
5289 context_switch (ecs->ptid);
5290
5291 current_inferior ()->waiting_for_vfork_done = 0;
5292 current_inferior ()->pspace->breakpoints_not_allowed = 0;
5293
5294 if (handle_stop_requested (ecs))
5295 return;
5296
5297 /* This also takes care of reinserting breakpoints in the
5298 previously locked inferior. */
5299 keep_going (ecs);
5300 return;
5301
5302 case TARGET_WAITKIND_EXECD:
5303 if (debug_infrun)
5304 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_EXECD\n");
5305
5306 /* Note we can't read registers yet (the stop_pc), because we
5307 don't yet know the inferior's post-exec architecture.
5308 'stop_pc' is explicitly read below instead. */
5309 if (!ptid_equal (ecs->ptid, inferior_ptid))
5310 switch_to_thread_no_regs (ecs->event_thread);
5311
5312 /* Do whatever is necessary to the parent branch of the vfork. */
5313 handle_vfork_child_exec_or_exit (1);
5314
5315 /* This causes the eventpoints and symbol table to be reset.
5316 Must do this now, before trying to determine whether to
5317 stop. */
5318 follow_exec (inferior_ptid, ecs->ws.value.execd_pathname);
5319
5320 stop_pc = regcache_read_pc (get_thread_regcache (ecs->ptid));
5321
5322 /* In follow_exec we may have deleted the original thread and
5323 created a new one. Make sure that the event thread is the
5324 execd thread for that case (this is a nop otherwise). */
5325 ecs->event_thread = inferior_thread ();
5326
5327 ecs->event_thread->control.stop_bpstat
5328 = bpstat_stop_status (get_current_regcache ()->aspace (),
5329 stop_pc, ecs->ptid, &ecs->ws);
5330
5331 /* Note that this may be referenced from inside
5332 bpstat_stop_status above, through inferior_has_execd. */
5333 xfree (ecs->ws.value.execd_pathname);
5334 ecs->ws.value.execd_pathname = NULL;
5335
5336 if (handle_stop_requested (ecs))
5337 return;
5338
5339 /* If no catchpoint triggered for this, then keep going. */
5340 if (!bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
5341 {
5342 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
5343 keep_going (ecs);
5344 return;
5345 }
5346 process_event_stop_test (ecs);
5347 return;
5348
5349 /* Be careful not to try to gather much state about a thread
5350 that's in a syscall. It's frequently a losing proposition. */
5351 case TARGET_WAITKIND_SYSCALL_ENTRY:
5352 if (debug_infrun)
5353 fprintf_unfiltered (gdb_stdlog,
5354 "infrun: TARGET_WAITKIND_SYSCALL_ENTRY\n");
5355 /* Getting the current syscall number. */
5356 if (handle_syscall_event (ecs) == 0)
5357 process_event_stop_test (ecs);
5358 return;
5359
5360 /* Before examining the threads further, step this thread to
5361 get it entirely out of the syscall. (We get notice of the
5362 event when the thread is just on the verge of exiting a
5363 syscall. Stepping one instruction seems to get it back
5364 into user code.) */
5365 case TARGET_WAITKIND_SYSCALL_RETURN:
5366 if (debug_infrun)
5367 fprintf_unfiltered (gdb_stdlog,
5368 "infrun: TARGET_WAITKIND_SYSCALL_RETURN\n");
5369 if (handle_syscall_event (ecs) == 0)
5370 process_event_stop_test (ecs);
5371 return;
5372
5373 case TARGET_WAITKIND_STOPPED:
5374 if (debug_infrun)
5375 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_STOPPED\n");
5376 handle_signal_stop (ecs);
5377 return;
5378
5379 case TARGET_WAITKIND_NO_HISTORY:
5380 if (debug_infrun)
5381 fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_NO_HISTORY\n");
5382 /* Reverse execution: target ran out of history info. */
5383
5384 /* Switch to the stopped thread. */
5385 if (!ptid_equal (ecs->ptid, inferior_ptid))
5386 context_switch (ecs->ptid);
5387 if (debug_infrun)
5388 fprintf_unfiltered (gdb_stdlog, "infrun: stopped\n");
5389
5390 delete_just_stopped_threads_single_step_breakpoints ();
5391 stop_pc = regcache_read_pc (get_thread_regcache (inferior_ptid));
5392
5393 if (handle_stop_requested (ecs))
5394 return;
5395
5396 observer_notify_no_history ();
5397 stop_waiting (ecs);
5398 return;
5399 }
5400 }
5401
5402 /* A wrapper around handle_inferior_event_1, which also makes sure
5403 that all temporary struct value objects that were created during
5404 the handling of the event get deleted at the end. */
5405
5406 static void
5407 handle_inferior_event (struct execution_control_state *ecs)
5408 {
5409 struct value *mark = value_mark ();
5410
5411 handle_inferior_event_1 (ecs);
5412 /* Purge all temporary values created during the event handling,
5413 as it could be a long time before we return to the command level
5414 where such values would otherwise be purged. */
5415 value_free_to_mark (mark);
5416 }
5417
5418 /* Restart threads back to what they were trying to do back when we
5419 paused them for an in-line step-over. The EVENT_THREAD thread is
5420 ignored. */
5421
5422 static void
5423 restart_threads (struct thread_info *event_thread)
5424 {
5425 struct thread_info *tp;
5426
5427 /* In case the instruction just stepped spawned a new thread. */
5428 update_thread_list ();
5429
5430 ALL_NON_EXITED_THREADS (tp)
5431 {
5432 if (tp == event_thread)
5433 {
5434 if (debug_infrun)
5435 fprintf_unfiltered (gdb_stdlog,
5436 "infrun: restart threads: "
5437 "[%s] is event thread\n",
5438 target_pid_to_str (tp->ptid));
5439 continue;
5440 }
5441
5442 if (!(tp->state == THREAD_RUNNING || tp->control.in_infcall))
5443 {
5444 if (debug_infrun)
5445 fprintf_unfiltered (gdb_stdlog,
5446 "infrun: restart threads: "
5447 "[%s] not meant to be running\n",
5448 target_pid_to_str (tp->ptid));
5449 continue;
5450 }
5451
5452 if (tp->resumed)
5453 {
5454 if (debug_infrun)
5455 fprintf_unfiltered (gdb_stdlog,
5456 "infrun: restart threads: [%s] resumed\n",
5457 target_pid_to_str (tp->ptid));
5458 gdb_assert (tp->executing || tp->suspend.waitstatus_pending_p);
5459 continue;
5460 }
5461
5462 if (thread_is_in_step_over_chain (tp))
5463 {
5464 if (debug_infrun)
5465 fprintf_unfiltered (gdb_stdlog,
5466 "infrun: restart threads: "
5467 "[%s] needs step-over\n",
5468 target_pid_to_str (tp->ptid));
5469 gdb_assert (!tp->resumed);
5470 continue;
5471 }
5472
5473
5474 if (tp->suspend.waitstatus_pending_p)
5475 {
5476 if (debug_infrun)
5477 fprintf_unfiltered (gdb_stdlog,
5478 "infrun: restart threads: "
5479 "[%s] has pending status\n",
5480 target_pid_to_str (tp->ptid));
5481 tp->resumed = 1;
5482 continue;
5483 }
5484
5485 gdb_assert (!tp->stop_requested);
5486
5487 /* If some thread needs to start a step-over at this point, it
5488 should still be in the step-over queue, and thus skipped
5489 above. */
5490 if (thread_still_needs_step_over (tp))
5491 {
5492 internal_error (__FILE__, __LINE__,
5493 "thread [%s] needs a step-over, but not in "
5494 "step-over queue\n",
5495 target_pid_to_str (tp->ptid));
5496 }
5497
5498 if (currently_stepping (tp))
5499 {
5500 if (debug_infrun)
5501 fprintf_unfiltered (gdb_stdlog,
5502 "infrun: restart threads: [%s] was stepping\n",
5503 target_pid_to_str (tp->ptid));
5504 keep_going_stepped_thread (tp);
5505 }
5506 else
5507 {
5508 struct execution_control_state ecss;
5509 struct execution_control_state *ecs = &ecss;
5510
5511 if (debug_infrun)
5512 fprintf_unfiltered (gdb_stdlog,
5513 "infrun: restart threads: [%s] continuing\n",
5514 target_pid_to_str (tp->ptid));
5515 reset_ecs (ecs, tp);
5516 switch_to_thread (tp->ptid);
5517 keep_going_pass_signal (ecs);
5518 }
5519 }
5520 }
5521
5522 /* Callback for iterate_over_threads. Find a resumed thread that has
5523 a pending waitstatus. */
5524
5525 static int
5526 resumed_thread_with_pending_status (struct thread_info *tp,
5527 void *arg)
5528 {
5529 return (tp->resumed
5530 && tp->suspend.waitstatus_pending_p);
5531 }
5532
5533 /* Called when we get an event that may finish an in-line or
5534 out-of-line (displaced stepping) step-over started previously.
5535 Return true if the event is processed and we should go back to the
5536 event loop; false if the caller should continue processing the
5537 event. */
5538
5539 static int
5540 finish_step_over (struct execution_control_state *ecs)
5541 {
5542 int had_step_over_info;
5543
5544 displaced_step_fixup (ecs->ptid,
5545 ecs->event_thread->suspend.stop_signal);
5546
5547 had_step_over_info = step_over_info_valid_p ();
5548
5549 if (had_step_over_info)
5550 {
5551 /* If we're stepping over a breakpoint with all threads locked,
5552 then only the thread that was stepped should be reporting
5553 back an event. */
5554 gdb_assert (ecs->event_thread->control.trap_expected);
5555
5556 clear_step_over_info ();
5557 }
5558
5559 if (!target_is_non_stop_p ())
5560 return 0;
5561
5562 /* Start a new step-over in another thread if there's one that
5563 needs it. */
5564 start_step_over ();
5565
5566 /* If we were stepping over a breakpoint before, and haven't started
5567 a new in-line step-over sequence, then restart all other threads
5568 (except the event thread). We can't do this in all-stop, as then
5569 e.g., we wouldn't be able to issue any other remote packet until
5570 these other threads stop. */
5571 if (had_step_over_info && !step_over_info_valid_p ())
5572 {
5573 struct thread_info *pending;
5574
5575 /* If we only have threads with pending statuses, the restart
5576 below won't restart any thread and so nothing re-inserts the
5577 breakpoint we just stepped over. But we need it inserted
5578 when we later process the pending events, otherwise if
5579 another thread has a pending event for this breakpoint too,
5580 we'd discard its event (because the breakpoint that
5581 originally caused the event was no longer inserted). */
5582 context_switch (ecs->ptid);
5583 insert_breakpoints ();
5584
5585 restart_threads (ecs->event_thread);
5586
5587 /* If we have events pending, go through handle_inferior_event
5588 again, picking up a pending event at random. This avoids
5589 thread starvation. */
5590
5591 /* But not if we just stepped over a watchpoint in order to let
5592 the instruction execute so we can evaluate its expression.
5593 The set of watchpoints that triggered is recorded in the
5594 breakpoint objects themselves (see bp->watchpoint_triggered).
5595 If we processed another event first, that other event could
5596 clobber this info. */
5597 if (ecs->event_thread->stepping_over_watchpoint)
5598 return 0;
5599
5600 pending = iterate_over_threads (resumed_thread_with_pending_status,
5601 NULL);
5602 if (pending != NULL)
5603 {
5604 struct thread_info *tp = ecs->event_thread;
5605 struct regcache *regcache;
5606
5607 if (debug_infrun)
5608 {
5609 fprintf_unfiltered (gdb_stdlog,
5610 "infrun: found resumed threads with "
5611 "pending events, saving status\n");
5612 }
5613
5614 gdb_assert (pending != tp);
5615
5616 /* Record the event thread's event for later. */
5617 save_waitstatus (tp, &ecs->ws);
5618 /* This was cleared early, by handle_inferior_event. Set it
5619 so this pending event is considered by
5620 do_target_wait. */
5621 tp->resumed = 1;
5622
5623 gdb_assert (!tp->executing);
5624
5625 regcache = get_thread_regcache (tp->ptid);
5626 tp->suspend.stop_pc = regcache_read_pc (regcache);
5627
5628 if (debug_infrun)
5629 {
5630 fprintf_unfiltered (gdb_stdlog,
5631 "infrun: saved stop_pc=%s for %s "
5632 "(currently_stepping=%d)\n",
5633 paddress (target_gdbarch (),
5634 tp->suspend.stop_pc),
5635 target_pid_to_str (tp->ptid),
5636 currently_stepping (tp));
5637 }
5638
5639 /* This in-line step-over finished; clear this so we won't
5640 start a new one. This is what handle_signal_stop would
5641 do, if we returned false. */
5642 tp->stepping_over_breakpoint = 0;
5643
5644 /* Wake up the event loop again. */
5645 mark_async_event_handler (infrun_async_inferior_event_token);
5646
5647 prepare_to_wait (ecs);
5648 return 1;
5649 }
5650 }
5651
5652 return 0;
5653 }
5654
5655 /* Come here when the program has stopped with a signal. */
5656
5657 static void
5658 handle_signal_stop (struct execution_control_state *ecs)
5659 {
5660 struct frame_info *frame;
5661 struct gdbarch *gdbarch;
5662 int stopped_by_watchpoint;
5663 enum stop_kind stop_soon;
5664 int random_signal;
5665
5666 gdb_assert (ecs->ws.kind == TARGET_WAITKIND_STOPPED);
5667
5668 ecs->event_thread->suspend.stop_signal = ecs->ws.value.sig;
5669
5670 /* Do we need to clean up the state of a thread that has
5671 completed a displaced single-step? (Doing so usually affects
5672 the PC, so do it here, before we set stop_pc.) */
5673 if (finish_step_over (ecs))
5674 return;
5675
5676 /* If we either finished a single-step or hit a breakpoint, but
5677 the user wanted this thread to be stopped, pretend we got a
5678 SIG0 (generic unsignaled stop). */
5679 if (ecs->event_thread->stop_requested
5680 && ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
5681 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
5682
5683 stop_pc = regcache_read_pc (get_thread_regcache (ecs->ptid));
5684
5685 if (debug_infrun)
5686 {
5687 struct regcache *regcache = get_thread_regcache (ecs->ptid);
5688 struct gdbarch *gdbarch = regcache->arch ();
5689 scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
5690
5691 inferior_ptid = ecs->ptid;
5692
5693 fprintf_unfiltered (gdb_stdlog, "infrun: stop_pc = %s\n",
5694 paddress (gdbarch, stop_pc));
5695 if (target_stopped_by_watchpoint ())
5696 {
5697 CORE_ADDR addr;
5698
5699 fprintf_unfiltered (gdb_stdlog, "infrun: stopped by watchpoint\n");
5700
5701 if (target_stopped_data_address (&current_target, &addr))
5702 fprintf_unfiltered (gdb_stdlog,
5703 "infrun: stopped data address = %s\n",
5704 paddress (gdbarch, addr));
5705 else
5706 fprintf_unfiltered (gdb_stdlog,
5707 "infrun: (no data address available)\n");
5708 }
5709 }
5710
5711 /* This is originated from start_remote(), start_inferior() and
5712 shared libraries hook functions. */
5713 stop_soon = get_inferior_stop_soon (ecs->ptid);
5714 if (stop_soon == STOP_QUIETLY || stop_soon == STOP_QUIETLY_REMOTE)
5715 {
5716 if (!ptid_equal (ecs->ptid, inferior_ptid))
5717 context_switch (ecs->ptid);
5718 if (debug_infrun)
5719 fprintf_unfiltered (gdb_stdlog, "infrun: quietly stopped\n");
5720 stop_print_frame = 1;
5721 stop_waiting (ecs);
5722 return;
5723 }
5724
5725 /* This originates from attach_command(). We need to overwrite
5726 the stop_signal here, because some kernels don't ignore a
5727 SIGSTOP in a subsequent ptrace(PTRACE_CONT,SIGSTOP) call.
5728 See more comments in inferior.h. On the other hand, if we
5729 get a non-SIGSTOP, report it to the user - assume the backend
5730 will handle the SIGSTOP if it should show up later.
5731
5732 Also consider that the attach is complete when we see a
5733 SIGTRAP. Some systems (e.g. Windows), and stubs supporting
5734 target extended-remote report it instead of a SIGSTOP
5735 (e.g. gdbserver). We already rely on SIGTRAP being our
5736 signal, so this is no exception.
5737
5738 Also consider that the attach is complete when we see a
5739 GDB_SIGNAL_0. In non-stop mode, GDB will explicitly tell
5740 the target to stop all threads of the inferior, in case the
5741 low level attach operation doesn't stop them implicitly. If
5742 they weren't stopped implicitly, then the stub will report a
5743 GDB_SIGNAL_0, meaning: stopped for no particular reason
5744 other than GDB's request. */
5745 if (stop_soon == STOP_QUIETLY_NO_SIGSTOP
5746 && (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_STOP
5747 || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
5748 || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_0))
5749 {
5750 stop_print_frame = 1;
5751 stop_waiting (ecs);
5752 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
5753 return;
5754 }
5755
5756 /* See if something interesting happened to the non-current thread. If
5757 so, then switch to that thread. */
5758 if (!ptid_equal (ecs->ptid, inferior_ptid))
5759 {
5760 if (debug_infrun)
5761 fprintf_unfiltered (gdb_stdlog, "infrun: context switch\n");
5762
5763 context_switch (ecs->ptid);
5764
5765 if (deprecated_context_hook)
5766 deprecated_context_hook (ptid_to_global_thread_id (ecs->ptid));
5767 }
5768
5769 /* At this point, get hold of the now-current thread's frame. */
5770 frame = get_current_frame ();
5771 gdbarch = get_frame_arch (frame);
5772
5773 /* Pull the single step breakpoints out of the target. */
5774 if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
5775 {
5776 struct regcache *regcache;
5777 CORE_ADDR pc;
5778
5779 regcache = get_thread_regcache (ecs->ptid);
5780 const address_space *aspace = regcache->aspace ();
5781
5782 pc = regcache_read_pc (regcache);
5783
5784 /* However, before doing so, if this single-step breakpoint was
5785 actually for another thread, set this thread up for moving
5786 past it. */
5787 if (!thread_has_single_step_breakpoint_here (ecs->event_thread,
5788 aspace, pc))
5789 {
5790 if (single_step_breakpoint_inserted_here_p (aspace, pc))
5791 {
5792 if (debug_infrun)
5793 {
5794 fprintf_unfiltered (gdb_stdlog,
5795 "infrun: [%s] hit another thread's "
5796 "single-step breakpoint\n",
5797 target_pid_to_str (ecs->ptid));
5798 }
5799 ecs->hit_singlestep_breakpoint = 1;
5800 }
5801 }
5802 else
5803 {
5804 if (debug_infrun)
5805 {
5806 fprintf_unfiltered (gdb_stdlog,
5807 "infrun: [%s] hit its "
5808 "single-step breakpoint\n",
5809 target_pid_to_str (ecs->ptid));
5810 }
5811 }
5812 }
5813 delete_just_stopped_threads_single_step_breakpoints ();
5814
5815 if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
5816 && ecs->event_thread->control.trap_expected
5817 && ecs->event_thread->stepping_over_watchpoint)
5818 stopped_by_watchpoint = 0;
5819 else
5820 stopped_by_watchpoint = watchpoints_triggered (&ecs->ws);
5821
5822 /* If necessary, step over this watchpoint. We'll be back to display
5823 it in a moment. */
5824 if (stopped_by_watchpoint
5825 && (target_have_steppable_watchpoint
5826 || gdbarch_have_nonsteppable_watchpoint (gdbarch)))
5827 {
5828 /* At this point, we are stopped at an instruction which has
5829 attempted to write to a piece of memory under control of
5830 a watchpoint. The instruction hasn't actually executed
5831 yet. If we were to evaluate the watchpoint expression
5832 now, we would get the old value, and therefore no change
5833 would seem to have occurred.
5834
5835 In order to make watchpoints work `right', we really need
5836 to complete the memory write, and then evaluate the
5837 watchpoint expression. We do this by single-stepping the
5838 target.
5839
5840 It may not be necessary to disable the watchpoint to step over
5841 it. For example, the PA can (with some kernel cooperation)
5842 single step over a watchpoint without disabling the watchpoint.
5843
5844 It is far more common to need to disable a watchpoint to step
5845 the inferior over it. If we have non-steppable watchpoints,
5846 we must disable the current watchpoint; it's simplest to
5847 disable all watchpoints.
5848
5849 Any breakpoint at PC must also be stepped over -- if there's
5850 one, it will have already triggered before the watchpoint
5851 triggered, and we either already reported it to the user, or
5852 it didn't cause a stop and we called keep_going. In either
5853 case, if there was a breakpoint at PC, we must be trying to
5854 step past it. */
5855 ecs->event_thread->stepping_over_watchpoint = 1;
5856 keep_going (ecs);
5857 return;
5858 }
5859
5860 ecs->event_thread->stepping_over_breakpoint = 0;
5861 ecs->event_thread->stepping_over_watchpoint = 0;
5862 bpstat_clear (&ecs->event_thread->control.stop_bpstat);
5863 ecs->event_thread->control.stop_step = 0;
5864 stop_print_frame = 1;
5865 stopped_by_random_signal = 0;
5866
5867 /* Hide inlined functions starting here, unless we just performed stepi or
5868 nexti. After stepi and nexti, always show the innermost frame (not any
5869 inline function call sites). */
5870 if (ecs->event_thread->control.step_range_end != 1)
5871 {
5872 const address_space *aspace =
5873 get_thread_regcache (ecs->ptid)->aspace ();
5874
5875 /* skip_inline_frames is expensive, so we avoid it if we can
5876 determine that the address is one where functions cannot have
5877 been inlined. This improves performance with inferiors that
5878 load a lot of shared libraries, because the solib event
5879 breakpoint is defined as the address of a function (i.e. not
5880 inline). Note that we have to check the previous PC as well
5881 as the current one to catch cases when we have just
5882 single-stepped off a breakpoint prior to reinstating it.
5883 Note that we're assuming that the code we single-step to is
5884 not inline, but that's not definitive: there's nothing
5885 preventing the event breakpoint function from containing
5886 inlined code, and the single-step ending up there. If the
5887 user had set a breakpoint on that inlined code, the missing
5888 skip_inline_frames call would break things. Fortunately
5889 that's an extremely unlikely scenario. */
5890 if (!pc_at_non_inline_function (aspace, stop_pc, &ecs->ws)
5891 && !(ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
5892 && ecs->event_thread->control.trap_expected
5893 && pc_at_non_inline_function (aspace,
5894 ecs->event_thread->prev_pc,
5895 &ecs->ws)))
5896 {
5897 skip_inline_frames (ecs->ptid);
5898
5899 /* Re-fetch current thread's frame in case that invalidated
5900 the frame cache. */
5901 frame = get_current_frame ();
5902 gdbarch = get_frame_arch (frame);
5903 }
5904 }
5905
5906 if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
5907 && ecs->event_thread->control.trap_expected
5908 && gdbarch_single_step_through_delay_p (gdbarch)
5909 && currently_stepping (ecs->event_thread))
5910 {
5911 /* We're trying to step off a breakpoint. Turns out that we're
5912 also on an instruction that needs to be stepped multiple
5913 times before it's been fully executing. E.g., architectures
5914 with a delay slot. It needs to be stepped twice, once for
5915 the instruction and once for the delay slot. */
5916 int step_through_delay
5917 = gdbarch_single_step_through_delay (gdbarch, frame);
5918
5919 if (debug_infrun && step_through_delay)
5920 fprintf_unfiltered (gdb_stdlog, "infrun: step through delay\n");
5921 if (ecs->event_thread->control.step_range_end == 0
5922 && step_through_delay)
5923 {
5924 /* The user issued a continue when stopped at a breakpoint.
5925 Set up for another trap and get out of here. */
5926 ecs->event_thread->stepping_over_breakpoint = 1;
5927 keep_going (ecs);
5928 return;
5929 }
5930 else if (step_through_delay)
5931 {
5932 /* The user issued a step when stopped at a breakpoint.
5933 Maybe we should stop, maybe we should not - the delay
5934 slot *might* correspond to a line of source. In any
5935 case, don't decide that here, just set
5936 ecs->stepping_over_breakpoint, making sure we
5937 single-step again before breakpoints are re-inserted. */
5938 ecs->event_thread->stepping_over_breakpoint = 1;
5939 }
5940 }
5941
5942 /* See if there is a breakpoint/watchpoint/catchpoint/etc. that
5943 handles this event. */
5944 ecs->event_thread->control.stop_bpstat
5945 = bpstat_stop_status (get_current_regcache ()->aspace (),
5946 stop_pc, ecs->ptid, &ecs->ws);
5947
5948 /* Following in case break condition called a
5949 function. */
5950 stop_print_frame = 1;
5951
5952 /* This is where we handle "moribund" watchpoints. Unlike
5953 software breakpoints traps, hardware watchpoint traps are
5954 always distinguishable from random traps. If no high-level
5955 watchpoint is associated with the reported stop data address
5956 anymore, then the bpstat does not explain the signal ---
5957 simply make sure to ignore it if `stopped_by_watchpoint' is
5958 set. */
5959
5960 if (debug_infrun
5961 && ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
5962 && !bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
5963 GDB_SIGNAL_TRAP)
5964 && stopped_by_watchpoint)
5965 fprintf_unfiltered (gdb_stdlog,
5966 "infrun: no user watchpoint explains "
5967 "watchpoint SIGTRAP, ignoring\n");
5968
5969 /* NOTE: cagney/2003-03-29: These checks for a random signal
5970 at one stage in the past included checks for an inferior
5971 function call's call dummy's return breakpoint. The original
5972 comment, that went with the test, read:
5973
5974 ``End of a stack dummy. Some systems (e.g. Sony news) give
5975 another signal besides SIGTRAP, so check here as well as
5976 above.''
5977
5978 If someone ever tries to get call dummys on a
5979 non-executable stack to work (where the target would stop
5980 with something like a SIGSEGV), then those tests might need
5981 to be re-instated. Given, however, that the tests were only
5982 enabled when momentary breakpoints were not being used, I
5983 suspect that it won't be the case.
5984
5985 NOTE: kettenis/2004-02-05: Indeed such checks don't seem to
5986 be necessary for call dummies on a non-executable stack on
5987 SPARC. */
5988
5989 /* See if the breakpoints module can explain the signal. */
5990 random_signal
5991 = !bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
5992 ecs->event_thread->suspend.stop_signal);
5993
5994 /* Maybe this was a trap for a software breakpoint that has since
5995 been removed. */
5996 if (random_signal && target_stopped_by_sw_breakpoint ())
5997 {
5998 if (program_breakpoint_here_p (gdbarch, stop_pc))
5999 {
6000 struct regcache *regcache;
6001 int decr_pc;
6002
6003 /* Re-adjust PC to what the program would see if GDB was not
6004 debugging it. */
6005 regcache = get_thread_regcache (ecs->event_thread->ptid);
6006 decr_pc = gdbarch_decr_pc_after_break (gdbarch);
6007 if (decr_pc != 0)
6008 {
6009 gdb::optional<scoped_restore_tmpl<int>>
6010 restore_operation_disable;
6011
6012 if (record_full_is_used ())
6013 restore_operation_disable.emplace
6014 (record_full_gdb_operation_disable_set ());
6015
6016 regcache_write_pc (regcache, stop_pc + decr_pc);
6017 }
6018 }
6019 else
6020 {
6021 /* A delayed software breakpoint event. Ignore the trap. */
6022 if (debug_infrun)
6023 fprintf_unfiltered (gdb_stdlog,
6024 "infrun: delayed software breakpoint "
6025 "trap, ignoring\n");
6026 random_signal = 0;
6027 }
6028 }
6029
6030 /* Maybe this was a trap for a hardware breakpoint/watchpoint that
6031 has since been removed. */
6032 if (random_signal && target_stopped_by_hw_breakpoint ())
6033 {
6034 /* A delayed hardware breakpoint event. Ignore the trap. */
6035 if (debug_infrun)
6036 fprintf_unfiltered (gdb_stdlog,
6037 "infrun: delayed hardware breakpoint/watchpoint "
6038 "trap, ignoring\n");
6039 random_signal = 0;
6040 }
6041
6042 /* If not, perhaps stepping/nexting can. */
6043 if (random_signal)
6044 random_signal = !(ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
6045 && currently_stepping (ecs->event_thread));
6046
6047 /* Perhaps the thread hit a single-step breakpoint of _another_
6048 thread. Single-step breakpoints are transparent to the
6049 breakpoints module. */
6050 if (random_signal)
6051 random_signal = !ecs->hit_singlestep_breakpoint;
6052
6053 /* No? Perhaps we got a moribund watchpoint. */
6054 if (random_signal)
6055 random_signal = !stopped_by_watchpoint;
6056
6057 /* Always stop if the user explicitly requested this thread to
6058 remain stopped. */
6059 if (ecs->event_thread->stop_requested)
6060 {
6061 random_signal = 1;
6062 if (debug_infrun)
6063 fprintf_unfiltered (gdb_stdlog, "infrun: user-requested stop\n");
6064 }
6065
6066 /* For the program's own signals, act according to
6067 the signal handling tables. */
6068
6069 if (random_signal)
6070 {
6071 /* Signal not for debugging purposes. */
6072 struct inferior *inf = find_inferior_ptid (ecs->ptid);
6073 enum gdb_signal stop_signal = ecs->event_thread->suspend.stop_signal;
6074
6075 if (debug_infrun)
6076 fprintf_unfiltered (gdb_stdlog, "infrun: random signal (%s)\n",
6077 gdb_signal_to_symbol_string (stop_signal));
6078
6079 stopped_by_random_signal = 1;
6080
6081 /* Always stop on signals if we're either just gaining control
6082 of the program, or the user explicitly requested this thread
6083 to remain stopped. */
6084 if (stop_soon != NO_STOP_QUIETLY
6085 || ecs->event_thread->stop_requested
6086 || (!inf->detaching
6087 && signal_stop_state (ecs->event_thread->suspend.stop_signal)))
6088 {
6089 stop_waiting (ecs);
6090 return;
6091 }
6092
6093 /* Notify observers the signal has "handle print" set. Note we
6094 returned early above if stopping; normal_stop handles the
6095 printing in that case. */
6096 if (signal_print[ecs->event_thread->suspend.stop_signal])
6097 {
6098 /* The signal table tells us to print about this signal. */
6099 target_terminal::ours_for_output ();
6100 observer_notify_signal_received (ecs->event_thread->suspend.stop_signal);
6101 target_terminal::inferior ();
6102 }
6103
6104 /* Clear the signal if it should not be passed. */
6105 if (signal_program[ecs->event_thread->suspend.stop_signal] == 0)
6106 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
6107
6108 if (ecs->event_thread->prev_pc == stop_pc
6109 && ecs->event_thread->control.trap_expected
6110 && ecs->event_thread->control.step_resume_breakpoint == NULL)
6111 {
6112 /* We were just starting a new sequence, attempting to
6113 single-step off of a breakpoint and expecting a SIGTRAP.
6114 Instead this signal arrives. This signal will take us out
6115 of the stepping range so GDB needs to remember to, when
6116 the signal handler returns, resume stepping off that
6117 breakpoint. */
6118 /* To simplify things, "continue" is forced to use the same
6119 code paths as single-step - set a breakpoint at the
6120 signal return address and then, once hit, step off that
6121 breakpoint. */
6122 if (debug_infrun)
6123 fprintf_unfiltered (gdb_stdlog,
6124 "infrun: signal arrived while stepping over "
6125 "breakpoint\n");
6126
6127 insert_hp_step_resume_breakpoint_at_frame (frame);
6128 ecs->event_thread->step_after_step_resume_breakpoint = 1;
6129 /* Reset trap_expected to ensure breakpoints are re-inserted. */
6130 ecs->event_thread->control.trap_expected = 0;
6131
6132 /* If we were nexting/stepping some other thread, switch to
6133 it, so that we don't continue it, losing control. */
6134 if (!switch_back_to_stepped_thread (ecs))
6135 keep_going (ecs);
6136 return;
6137 }
6138
6139 if (ecs->event_thread->suspend.stop_signal != GDB_SIGNAL_0
6140 && (pc_in_thread_step_range (stop_pc, ecs->event_thread)
6141 || ecs->event_thread->control.step_range_end == 1)
6142 && frame_id_eq (get_stack_frame_id (frame),
6143 ecs->event_thread->control.step_stack_frame_id)
6144 && ecs->event_thread->control.step_resume_breakpoint == NULL)
6145 {
6146 /* The inferior is about to take a signal that will take it
6147 out of the single step range. Set a breakpoint at the
6148 current PC (which is presumably where the signal handler
6149 will eventually return) and then allow the inferior to
6150 run free.
6151
6152 Note that this is only needed for a signal delivered
6153 while in the single-step range. Nested signals aren't a
6154 problem as they eventually all return. */
6155 if (debug_infrun)
6156 fprintf_unfiltered (gdb_stdlog,
6157 "infrun: signal may take us out of "
6158 "single-step range\n");
6159
6160 clear_step_over_info ();
6161 insert_hp_step_resume_breakpoint_at_frame (frame);
6162 ecs->event_thread->step_after_step_resume_breakpoint = 1;
6163 /* Reset trap_expected to ensure breakpoints are re-inserted. */
6164 ecs->event_thread->control.trap_expected = 0;
6165 keep_going (ecs);
6166 return;
6167 }
6168
6169 /* Note: step_resume_breakpoint may be non-NULL. This occures
6170 when either there's a nested signal, or when there's a
6171 pending signal enabled just as the signal handler returns
6172 (leaving the inferior at the step-resume-breakpoint without
6173 actually executing it). Either way continue until the
6174 breakpoint is really hit. */
6175
6176 if (!switch_back_to_stepped_thread (ecs))
6177 {
6178 if (debug_infrun)
6179 fprintf_unfiltered (gdb_stdlog,
6180 "infrun: random signal, keep going\n");
6181
6182 keep_going (ecs);
6183 }
6184 return;
6185 }
6186
6187 process_event_stop_test (ecs);
6188 }
6189
6190 /* Come here when we've got some debug event / signal we can explain
6191 (IOW, not a random signal), and test whether it should cause a
6192 stop, or whether we should resume the inferior (transparently).
6193 E.g., could be a breakpoint whose condition evaluates false; we
6194 could be still stepping within the line; etc. */
6195
6196 static void
6197 process_event_stop_test (struct execution_control_state *ecs)
6198 {
6199 struct symtab_and_line stop_pc_sal;
6200 struct frame_info *frame;
6201 struct gdbarch *gdbarch;
6202 CORE_ADDR jmp_buf_pc;
6203 struct bpstat_what what;
6204
6205 /* Handle cases caused by hitting a breakpoint. */
6206
6207 frame = get_current_frame ();
6208 gdbarch = get_frame_arch (frame);
6209
6210 what = bpstat_what (ecs->event_thread->control.stop_bpstat);
6211
6212 if (what.call_dummy)
6213 {
6214 stop_stack_dummy = what.call_dummy;
6215 }
6216
6217 /* A few breakpoint types have callbacks associated (e.g.,
6218 bp_jit_event). Run them now. */
6219 bpstat_run_callbacks (ecs->event_thread->control.stop_bpstat);
6220
6221 /* If we hit an internal event that triggers symbol changes, the
6222 current frame will be invalidated within bpstat_what (e.g., if we
6223 hit an internal solib event). Re-fetch it. */
6224 frame = get_current_frame ();
6225 gdbarch = get_frame_arch (frame);
6226
6227 switch (what.main_action)
6228 {
6229 case BPSTAT_WHAT_SET_LONGJMP_RESUME:
6230 /* If we hit the breakpoint at longjmp while stepping, we
6231 install a momentary breakpoint at the target of the
6232 jmp_buf. */
6233
6234 if (debug_infrun)
6235 fprintf_unfiltered (gdb_stdlog,
6236 "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME\n");
6237
6238 ecs->event_thread->stepping_over_breakpoint = 1;
6239
6240 if (what.is_longjmp)
6241 {
6242 struct value *arg_value;
6243
6244 /* If we set the longjmp breakpoint via a SystemTap probe,
6245 then use it to extract the arguments. The destination PC
6246 is the third argument to the probe. */
6247 arg_value = probe_safe_evaluate_at_pc (frame, 2);
6248 if (arg_value)
6249 {
6250 jmp_buf_pc = value_as_address (arg_value);
6251 jmp_buf_pc = gdbarch_addr_bits_remove (gdbarch, jmp_buf_pc);
6252 }
6253 else if (!gdbarch_get_longjmp_target_p (gdbarch)
6254 || !gdbarch_get_longjmp_target (gdbarch,
6255 frame, &jmp_buf_pc))
6256 {
6257 if (debug_infrun)
6258 fprintf_unfiltered (gdb_stdlog,
6259 "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME "
6260 "(!gdbarch_get_longjmp_target)\n");
6261 keep_going (ecs);
6262 return;
6263 }
6264
6265 /* Insert a breakpoint at resume address. */
6266 insert_longjmp_resume_breakpoint (gdbarch, jmp_buf_pc);
6267 }
6268 else
6269 check_exception_resume (ecs, frame);
6270 keep_going (ecs);
6271 return;
6272
6273 case BPSTAT_WHAT_CLEAR_LONGJMP_RESUME:
6274 {
6275 struct frame_info *init_frame;
6276
6277 /* There are several cases to consider.
6278
6279 1. The initiating frame no longer exists. In this case we
6280 must stop, because the exception or longjmp has gone too
6281 far.
6282
6283 2. The initiating frame exists, and is the same as the
6284 current frame. We stop, because the exception or longjmp
6285 has been caught.
6286
6287 3. The initiating frame exists and is different from the
6288 current frame. This means the exception or longjmp has
6289 been caught beneath the initiating frame, so keep going.
6290
6291 4. longjmp breakpoint has been placed just to protect
6292 against stale dummy frames and user is not interested in
6293 stopping around longjmps. */
6294
6295 if (debug_infrun)
6296 fprintf_unfiltered (gdb_stdlog,
6297 "infrun: BPSTAT_WHAT_CLEAR_LONGJMP_RESUME\n");
6298
6299 gdb_assert (ecs->event_thread->control.exception_resume_breakpoint
6300 != NULL);
6301 delete_exception_resume_breakpoint (ecs->event_thread);
6302
6303 if (what.is_longjmp)
6304 {
6305 check_longjmp_breakpoint_for_call_dummy (ecs->event_thread);
6306
6307 if (!frame_id_p (ecs->event_thread->initiating_frame))
6308 {
6309 /* Case 4. */
6310 keep_going (ecs);
6311 return;
6312 }
6313 }
6314
6315 init_frame = frame_find_by_id (ecs->event_thread->initiating_frame);
6316
6317 if (init_frame)
6318 {
6319 struct frame_id current_id
6320 = get_frame_id (get_current_frame ());
6321 if (frame_id_eq (current_id,
6322 ecs->event_thread->initiating_frame))
6323 {
6324 /* Case 2. Fall through. */
6325 }
6326 else
6327 {
6328 /* Case 3. */
6329 keep_going (ecs);
6330 return;
6331 }
6332 }
6333
6334 /* For Cases 1 and 2, remove the step-resume breakpoint, if it
6335 exists. */
6336 delete_step_resume_breakpoint (ecs->event_thread);
6337
6338 end_stepping_range (ecs);
6339 }
6340 return;
6341
6342 case BPSTAT_WHAT_SINGLE:
6343 if (debug_infrun)
6344 fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SINGLE\n");
6345 ecs->event_thread->stepping_over_breakpoint = 1;
6346 /* Still need to check other stuff, at least the case where we
6347 are stepping and step out of the right range. */
6348 break;
6349
6350 case BPSTAT_WHAT_STEP_RESUME:
6351 if (debug_infrun)
6352 fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STEP_RESUME\n");
6353
6354 delete_step_resume_breakpoint (ecs->event_thread);
6355 if (ecs->event_thread->control.proceed_to_finish
6356 && execution_direction == EXEC_REVERSE)
6357 {
6358 struct thread_info *tp = ecs->event_thread;
6359
6360 /* We are finishing a function in reverse, and just hit the
6361 step-resume breakpoint at the start address of the
6362 function, and we're almost there -- just need to back up
6363 by one more single-step, which should take us back to the
6364 function call. */
6365 tp->control.step_range_start = tp->control.step_range_end = 1;
6366 keep_going (ecs);
6367 return;
6368 }
6369 fill_in_stop_func (gdbarch, ecs);
6370 if (stop_pc == ecs->stop_func_start
6371 && execution_direction == EXEC_REVERSE)
6372 {
6373 /* We are stepping over a function call in reverse, and just
6374 hit the step-resume breakpoint at the start address of
6375 the function. Go back to single-stepping, which should
6376 take us back to the function call. */
6377 ecs->event_thread->stepping_over_breakpoint = 1;
6378 keep_going (ecs);
6379 return;
6380 }
6381 break;
6382
6383 case BPSTAT_WHAT_STOP_NOISY:
6384 if (debug_infrun)
6385 fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STOP_NOISY\n");
6386 stop_print_frame = 1;
6387
6388 /* Assume the thread stopped for a breapoint. We'll still check
6389 whether a/the breakpoint is there when the thread is next
6390 resumed. */
6391 ecs->event_thread->stepping_over_breakpoint = 1;
6392
6393 stop_waiting (ecs);
6394 return;
6395
6396 case BPSTAT_WHAT_STOP_SILENT:
6397 if (debug_infrun)
6398 fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STOP_SILENT\n");
6399 stop_print_frame = 0;
6400
6401 /* Assume the thread stopped for a breapoint. We'll still check
6402 whether a/the breakpoint is there when the thread is next
6403 resumed. */
6404 ecs->event_thread->stepping_over_breakpoint = 1;
6405 stop_waiting (ecs);
6406 return;
6407
6408 case BPSTAT_WHAT_HP_STEP_RESUME:
6409 if (debug_infrun)
6410 fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_HP_STEP_RESUME\n");
6411
6412 delete_step_resume_breakpoint (ecs->event_thread);
6413 if (ecs->event_thread->step_after_step_resume_breakpoint)
6414 {
6415 /* Back when the step-resume breakpoint was inserted, we
6416 were trying to single-step off a breakpoint. Go back to
6417 doing that. */
6418 ecs->event_thread->step_after_step_resume_breakpoint = 0;
6419 ecs->event_thread->stepping_over_breakpoint = 1;
6420 keep_going (ecs);
6421 return;
6422 }
6423 break;
6424
6425 case BPSTAT_WHAT_KEEP_CHECKING:
6426 break;
6427 }
6428
6429 /* If we stepped a permanent breakpoint and we had a high priority
6430 step-resume breakpoint for the address we stepped, but we didn't
6431 hit it, then we must have stepped into the signal handler. The
6432 step-resume was only necessary to catch the case of _not_
6433 stepping into the handler, so delete it, and fall through to
6434 checking whether the step finished. */
6435 if (ecs->event_thread->stepped_breakpoint)
6436 {
6437 struct breakpoint *sr_bp
6438 = ecs->event_thread->control.step_resume_breakpoint;
6439
6440 if (sr_bp != NULL
6441 && sr_bp->loc->permanent
6442 && sr_bp->type == bp_hp_step_resume
6443 && sr_bp->loc->address == ecs->event_thread->prev_pc)
6444 {
6445 if (debug_infrun)
6446 fprintf_unfiltered (gdb_stdlog,
6447 "infrun: stepped permanent breakpoint, stopped in "
6448 "handler\n");
6449 delete_step_resume_breakpoint (ecs->event_thread);
6450 ecs->event_thread->step_after_step_resume_breakpoint = 0;
6451 }
6452 }
6453
6454 /* We come here if we hit a breakpoint but should not stop for it.
6455 Possibly we also were stepping and should stop for that. So fall
6456 through and test for stepping. But, if not stepping, do not
6457 stop. */
6458
6459 /* In all-stop mode, if we're currently stepping but have stopped in
6460 some other thread, we need to switch back to the stepped thread. */
6461 if (switch_back_to_stepped_thread (ecs))
6462 return;
6463
6464 if (ecs->event_thread->control.step_resume_breakpoint)
6465 {
6466 if (debug_infrun)
6467 fprintf_unfiltered (gdb_stdlog,
6468 "infrun: step-resume breakpoint is inserted\n");
6469
6470 /* Having a step-resume breakpoint overrides anything
6471 else having to do with stepping commands until
6472 that breakpoint is reached. */
6473 keep_going (ecs);
6474 return;
6475 }
6476
6477 if (ecs->event_thread->control.step_range_end == 0)
6478 {
6479 if (debug_infrun)
6480 fprintf_unfiltered (gdb_stdlog, "infrun: no stepping, continue\n");
6481 /* Likewise if we aren't even stepping. */
6482 keep_going (ecs);
6483 return;
6484 }
6485
6486 /* Re-fetch current thread's frame in case the code above caused
6487 the frame cache to be re-initialized, making our FRAME variable
6488 a dangling pointer. */
6489 frame = get_current_frame ();
6490 gdbarch = get_frame_arch (frame);
6491 fill_in_stop_func (gdbarch, ecs);
6492
6493 /* If stepping through a line, keep going if still within it.
6494
6495 Note that step_range_end is the address of the first instruction
6496 beyond the step range, and NOT the address of the last instruction
6497 within it!
6498
6499 Note also that during reverse execution, we may be stepping
6500 through a function epilogue and therefore must detect when
6501 the current-frame changes in the middle of a line. */
6502
6503 if (pc_in_thread_step_range (stop_pc, ecs->event_thread)
6504 && (execution_direction != EXEC_REVERSE
6505 || frame_id_eq (get_frame_id (frame),
6506 ecs->event_thread->control.step_frame_id)))
6507 {
6508 if (debug_infrun)
6509 fprintf_unfiltered
6510 (gdb_stdlog, "infrun: stepping inside range [%s-%s]\n",
6511 paddress (gdbarch, ecs->event_thread->control.step_range_start),
6512 paddress (gdbarch, ecs->event_thread->control.step_range_end));
6513
6514 /* Tentatively re-enable range stepping; `resume' disables it if
6515 necessary (e.g., if we're stepping over a breakpoint or we
6516 have software watchpoints). */
6517 ecs->event_thread->control.may_range_step = 1;
6518
6519 /* When stepping backward, stop at beginning of line range
6520 (unless it's the function entry point, in which case
6521 keep going back to the call point). */
6522 if (stop_pc == ecs->event_thread->control.step_range_start
6523 && stop_pc != ecs->stop_func_start
6524 && execution_direction == EXEC_REVERSE)
6525 end_stepping_range (ecs);
6526 else
6527 keep_going (ecs);
6528
6529 return;
6530 }
6531
6532 /* We stepped out of the stepping range. */
6533
6534 /* If we are stepping at the source level and entered the runtime
6535 loader dynamic symbol resolution code...
6536
6537 EXEC_FORWARD: we keep on single stepping until we exit the run
6538 time loader code and reach the callee's address.
6539
6540 EXEC_REVERSE: we've already executed the callee (backward), and
6541 the runtime loader code is handled just like any other
6542 undebuggable function call. Now we need only keep stepping
6543 backward through the trampoline code, and that's handled further
6544 down, so there is nothing for us to do here. */
6545
6546 if (execution_direction != EXEC_REVERSE
6547 && ecs->event_thread->control.step_over_calls == STEP_OVER_UNDEBUGGABLE
6548 && in_solib_dynsym_resolve_code (stop_pc))
6549 {
6550 CORE_ADDR pc_after_resolver =
6551 gdbarch_skip_solib_resolver (gdbarch, stop_pc);
6552
6553 if (debug_infrun)
6554 fprintf_unfiltered (gdb_stdlog,
6555 "infrun: stepped into dynsym resolve code\n");
6556
6557 if (pc_after_resolver)
6558 {
6559 /* Set up a step-resume breakpoint at the address
6560 indicated by SKIP_SOLIB_RESOLVER. */
6561 symtab_and_line sr_sal;
6562 sr_sal.pc = pc_after_resolver;
6563 sr_sal.pspace = get_frame_program_space (frame);
6564
6565 insert_step_resume_breakpoint_at_sal (gdbarch,
6566 sr_sal, null_frame_id);
6567 }
6568
6569 keep_going (ecs);
6570 return;
6571 }
6572
6573 if (ecs->event_thread->control.step_range_end != 1
6574 && (ecs->event_thread->control.step_over_calls == STEP_OVER_UNDEBUGGABLE
6575 || ecs->event_thread->control.step_over_calls == STEP_OVER_ALL)
6576 && get_frame_type (frame) == SIGTRAMP_FRAME)
6577 {
6578 if (debug_infrun)
6579 fprintf_unfiltered (gdb_stdlog,
6580 "infrun: stepped into signal trampoline\n");
6581 /* The inferior, while doing a "step" or "next", has ended up in
6582 a signal trampoline (either by a signal being delivered or by
6583 the signal handler returning). Just single-step until the
6584 inferior leaves the trampoline (either by calling the handler
6585 or returning). */
6586 keep_going (ecs);
6587 return;
6588 }
6589
6590 /* If we're in the return path from a shared library trampoline,
6591 we want to proceed through the trampoline when stepping. */
6592 /* macro/2012-04-25: This needs to come before the subroutine
6593 call check below as on some targets return trampolines look
6594 like subroutine calls (MIPS16 return thunks). */
6595 if (gdbarch_in_solib_return_trampoline (gdbarch,
6596 stop_pc, ecs->stop_func_name)
6597 && ecs->event_thread->control.step_over_calls != STEP_OVER_NONE)
6598 {
6599 /* Determine where this trampoline returns. */
6600 CORE_ADDR real_stop_pc;
6601
6602 real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc);
6603
6604 if (debug_infrun)
6605 fprintf_unfiltered (gdb_stdlog,
6606 "infrun: stepped into solib return tramp\n");
6607
6608 /* Only proceed through if we know where it's going. */
6609 if (real_stop_pc)
6610 {
6611 /* And put the step-breakpoint there and go until there. */
6612 symtab_and_line sr_sal;
6613 sr_sal.pc = real_stop_pc;
6614 sr_sal.section = find_pc_overlay (sr_sal.pc);
6615 sr_sal.pspace = get_frame_program_space (frame);
6616
6617 /* Do not specify what the fp should be when we stop since
6618 on some machines the prologue is where the new fp value
6619 is established. */
6620 insert_step_resume_breakpoint_at_sal (gdbarch,
6621 sr_sal, null_frame_id);
6622
6623 /* Restart without fiddling with the step ranges or
6624 other state. */
6625 keep_going (ecs);
6626 return;
6627 }
6628 }
6629
6630 /* Check for subroutine calls. The check for the current frame
6631 equalling the step ID is not necessary - the check of the
6632 previous frame's ID is sufficient - but it is a common case and
6633 cheaper than checking the previous frame's ID.
6634
6635 NOTE: frame_id_eq will never report two invalid frame IDs as
6636 being equal, so to get into this block, both the current and
6637 previous frame must have valid frame IDs. */
6638 /* The outer_frame_id check is a heuristic to detect stepping
6639 through startup code. If we step over an instruction which
6640 sets the stack pointer from an invalid value to a valid value,
6641 we may detect that as a subroutine call from the mythical
6642 "outermost" function. This could be fixed by marking
6643 outermost frames as !stack_p,code_p,special_p. Then the
6644 initial outermost frame, before sp was valid, would
6645 have code_addr == &_start. See the comment in frame_id_eq
6646 for more. */
6647 if (!frame_id_eq (get_stack_frame_id (frame),
6648 ecs->event_thread->control.step_stack_frame_id)
6649 && (frame_id_eq (frame_unwind_caller_id (get_current_frame ()),
6650 ecs->event_thread->control.step_stack_frame_id)
6651 && (!frame_id_eq (ecs->event_thread->control.step_stack_frame_id,
6652 outer_frame_id)
6653 || (ecs->event_thread->control.step_start_function
6654 != find_pc_function (stop_pc)))))
6655 {
6656 CORE_ADDR real_stop_pc;
6657
6658 if (debug_infrun)
6659 fprintf_unfiltered (gdb_stdlog, "infrun: stepped into subroutine\n");
6660
6661 if (ecs->event_thread->control.step_over_calls == STEP_OVER_NONE)
6662 {
6663 /* I presume that step_over_calls is only 0 when we're
6664 supposed to be stepping at the assembly language level
6665 ("stepi"). Just stop. */
6666 /* And this works the same backward as frontward. MVS */
6667 end_stepping_range (ecs);
6668 return;
6669 }
6670
6671 /* Reverse stepping through solib trampolines. */
6672
6673 if (execution_direction == EXEC_REVERSE
6674 && ecs->event_thread->control.step_over_calls != STEP_OVER_NONE
6675 && (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
6676 || (ecs->stop_func_start == 0
6677 && in_solib_dynsym_resolve_code (stop_pc))))
6678 {
6679 /* Any solib trampoline code can be handled in reverse
6680 by simply continuing to single-step. We have already
6681 executed the solib function (backwards), and a few
6682 steps will take us back through the trampoline to the
6683 caller. */
6684 keep_going (ecs);
6685 return;
6686 }
6687
6688 if (ecs->event_thread->control.step_over_calls == STEP_OVER_ALL)
6689 {
6690 /* We're doing a "next".
6691
6692 Normal (forward) execution: set a breakpoint at the
6693 callee's return address (the address at which the caller
6694 will resume).
6695
6696 Reverse (backward) execution. set the step-resume
6697 breakpoint at the start of the function that we just
6698 stepped into (backwards), and continue to there. When we
6699 get there, we'll need to single-step back to the caller. */
6700
6701 if (execution_direction == EXEC_REVERSE)
6702 {
6703 /* If we're already at the start of the function, we've either
6704 just stepped backward into a single instruction function,
6705 or stepped back out of a signal handler to the first instruction
6706 of the function. Just keep going, which will single-step back
6707 to the caller. */
6708 if (ecs->stop_func_start != stop_pc && ecs->stop_func_start != 0)
6709 {
6710 /* Normal function call return (static or dynamic). */
6711 symtab_and_line sr_sal;
6712 sr_sal.pc = ecs->stop_func_start;
6713 sr_sal.pspace = get_frame_program_space (frame);
6714 insert_step_resume_breakpoint_at_sal (gdbarch,
6715 sr_sal, null_frame_id);
6716 }
6717 }
6718 else
6719 insert_step_resume_breakpoint_at_caller (frame);
6720
6721 keep_going (ecs);
6722 return;
6723 }
6724
6725 /* If we are in a function call trampoline (a stub between the
6726 calling routine and the real function), locate the real
6727 function. That's what tells us (a) whether we want to step
6728 into it at all, and (b) what prologue we want to run to the
6729 end of, if we do step into it. */
6730 real_stop_pc = skip_language_trampoline (frame, stop_pc);
6731 if (real_stop_pc == 0)
6732 real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc);
6733 if (real_stop_pc != 0)
6734 ecs->stop_func_start = real_stop_pc;
6735
6736 if (real_stop_pc != 0 && in_solib_dynsym_resolve_code (real_stop_pc))
6737 {
6738 symtab_and_line sr_sal;
6739 sr_sal.pc = ecs->stop_func_start;
6740 sr_sal.pspace = get_frame_program_space (frame);
6741
6742 insert_step_resume_breakpoint_at_sal (gdbarch,
6743 sr_sal, null_frame_id);
6744 keep_going (ecs);
6745 return;
6746 }
6747
6748 /* If we have line number information for the function we are
6749 thinking of stepping into and the function isn't on the skip
6750 list, step into it.
6751
6752 If there are several symtabs at that PC (e.g. with include
6753 files), just want to know whether *any* of them have line
6754 numbers. find_pc_line handles this. */
6755 {
6756 struct symtab_and_line tmp_sal;
6757
6758 tmp_sal = find_pc_line (ecs->stop_func_start, 0);
6759 if (tmp_sal.line != 0
6760 && !function_name_is_marked_for_skip (ecs->stop_func_name,
6761 tmp_sal))
6762 {
6763 if (execution_direction == EXEC_REVERSE)
6764 handle_step_into_function_backward (gdbarch, ecs);
6765 else
6766 handle_step_into_function (gdbarch, ecs);
6767 return;
6768 }
6769 }
6770
6771 /* If we have no line number and the step-stop-if-no-debug is
6772 set, we stop the step so that the user has a chance to switch
6773 in assembly mode. */
6774 if (ecs->event_thread->control.step_over_calls == STEP_OVER_UNDEBUGGABLE
6775 && step_stop_if_no_debug)
6776 {
6777 end_stepping_range (ecs);
6778 return;
6779 }
6780
6781 if (execution_direction == EXEC_REVERSE)
6782 {
6783 /* If we're already at the start of the function, we've either just
6784 stepped backward into a single instruction function without line
6785 number info, or stepped back out of a signal handler to the first
6786 instruction of the function without line number info. Just keep
6787 going, which will single-step back to the caller. */
6788 if (ecs->stop_func_start != stop_pc)
6789 {
6790 /* Set a breakpoint at callee's start address.
6791 From there we can step once and be back in the caller. */
6792 symtab_and_line sr_sal;
6793 sr_sal.pc = ecs->stop_func_start;
6794 sr_sal.pspace = get_frame_program_space (frame);
6795 insert_step_resume_breakpoint_at_sal (gdbarch,
6796 sr_sal, null_frame_id);
6797 }
6798 }
6799 else
6800 /* Set a breakpoint at callee's return address (the address
6801 at which the caller will resume). */
6802 insert_step_resume_breakpoint_at_caller (frame);
6803
6804 keep_going (ecs);
6805 return;
6806 }
6807
6808 /* Reverse stepping through solib trampolines. */
6809
6810 if (execution_direction == EXEC_REVERSE
6811 && ecs->event_thread->control.step_over_calls != STEP_OVER_NONE)
6812 {
6813 if (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
6814 || (ecs->stop_func_start == 0
6815 && in_solib_dynsym_resolve_code (stop_pc)))
6816 {
6817 /* Any solib trampoline code can be handled in reverse
6818 by simply continuing to single-step. We have already
6819 executed the solib function (backwards), and a few
6820 steps will take us back through the trampoline to the
6821 caller. */
6822 keep_going (ecs);
6823 return;
6824 }
6825 else if (in_solib_dynsym_resolve_code (stop_pc))
6826 {
6827 /* Stepped backward into the solib dynsym resolver.
6828 Set a breakpoint at its start and continue, then
6829 one more step will take us out. */
6830 symtab_and_line sr_sal;
6831 sr_sal.pc = ecs->stop_func_start;
6832 sr_sal.pspace = get_frame_program_space (frame);
6833 insert_step_resume_breakpoint_at_sal (gdbarch,
6834 sr_sal, null_frame_id);
6835 keep_going (ecs);
6836 return;
6837 }
6838 }
6839
6840 stop_pc_sal = find_pc_line (stop_pc, 0);
6841
6842 /* NOTE: tausq/2004-05-24: This if block used to be done before all
6843 the trampoline processing logic, however, there are some trampolines
6844 that have no names, so we should do trampoline handling first. */
6845 if (ecs->event_thread->control.step_over_calls == STEP_OVER_UNDEBUGGABLE
6846 && ecs->stop_func_name == NULL
6847 && stop_pc_sal.line == 0)
6848 {
6849 if (debug_infrun)
6850 fprintf_unfiltered (gdb_stdlog,
6851 "infrun: stepped into undebuggable function\n");
6852
6853 /* The inferior just stepped into, or returned to, an
6854 undebuggable function (where there is no debugging information
6855 and no line number corresponding to the address where the
6856 inferior stopped). Since we want to skip this kind of code,
6857 we keep going until the inferior returns from this
6858 function - unless the user has asked us not to (via
6859 set step-mode) or we no longer know how to get back
6860 to the call site. */
6861 if (step_stop_if_no_debug
6862 || !frame_id_p (frame_unwind_caller_id (frame)))
6863 {
6864 /* If we have no line number and the step-stop-if-no-debug
6865 is set, we stop the step so that the user has a chance to
6866 switch in assembly mode. */
6867 end_stepping_range (ecs);
6868 return;
6869 }
6870 else
6871 {
6872 /* Set a breakpoint at callee's return address (the address
6873 at which the caller will resume). */
6874 insert_step_resume_breakpoint_at_caller (frame);
6875 keep_going (ecs);
6876 return;
6877 }
6878 }
6879
6880 if (ecs->event_thread->control.step_range_end == 1)
6881 {
6882 /* It is stepi or nexti. We always want to stop stepping after
6883 one instruction. */
6884 if (debug_infrun)
6885 fprintf_unfiltered (gdb_stdlog, "infrun: stepi/nexti\n");
6886 end_stepping_range (ecs);
6887 return;
6888 }
6889
6890 if (stop_pc_sal.line == 0)
6891 {
6892 /* We have no line number information. That means to stop
6893 stepping (does this always happen right after one instruction,
6894 when we do "s" in a function with no line numbers,
6895 or can this happen as a result of a return or longjmp?). */
6896 if (debug_infrun)
6897 fprintf_unfiltered (gdb_stdlog, "infrun: no line number info\n");
6898 end_stepping_range (ecs);
6899 return;
6900 }
6901
6902 /* Look for "calls" to inlined functions, part one. If the inline
6903 frame machinery detected some skipped call sites, we have entered
6904 a new inline function. */
6905
6906 if (frame_id_eq (get_frame_id (get_current_frame ()),
6907 ecs->event_thread->control.step_frame_id)
6908 && inline_skipped_frames (ecs->ptid))
6909 {
6910 if (debug_infrun)
6911 fprintf_unfiltered (gdb_stdlog,
6912 "infrun: stepped into inlined function\n");
6913
6914 symtab_and_line call_sal = find_frame_sal (get_current_frame ());
6915
6916 if (ecs->event_thread->control.step_over_calls != STEP_OVER_ALL)
6917 {
6918 /* For "step", we're going to stop. But if the call site
6919 for this inlined function is on the same source line as
6920 we were previously stepping, go down into the function
6921 first. Otherwise stop at the call site. */
6922
6923 if (call_sal.line == ecs->event_thread->current_line
6924 && call_sal.symtab == ecs->event_thread->current_symtab)
6925 step_into_inline_frame (ecs->ptid);
6926
6927 end_stepping_range (ecs);
6928 return;
6929 }
6930 else
6931 {
6932 /* For "next", we should stop at the call site if it is on a
6933 different source line. Otherwise continue through the
6934 inlined function. */
6935 if (call_sal.line == ecs->event_thread->current_line
6936 && call_sal.symtab == ecs->event_thread->current_symtab)
6937 keep_going (ecs);
6938 else
6939 end_stepping_range (ecs);
6940 return;
6941 }
6942 }
6943
6944 /* Look for "calls" to inlined functions, part two. If we are still
6945 in the same real function we were stepping through, but we have
6946 to go further up to find the exact frame ID, we are stepping
6947 through a more inlined call beyond its call site. */
6948
6949 if (get_frame_type (get_current_frame ()) == INLINE_FRAME
6950 && !frame_id_eq (get_frame_id (get_current_frame ()),
6951 ecs->event_thread->control.step_frame_id)
6952 && stepped_in_from (get_current_frame (),
6953 ecs->event_thread->control.step_frame_id))
6954 {
6955 if (debug_infrun)
6956 fprintf_unfiltered (gdb_stdlog,
6957 "infrun: stepping through inlined function\n");
6958
6959 if (ecs->event_thread->control.step_over_calls == STEP_OVER_ALL)
6960 keep_going (ecs);
6961 else
6962 end_stepping_range (ecs);
6963 return;
6964 }
6965
6966 if ((stop_pc == stop_pc_sal.pc)
6967 && (ecs->event_thread->current_line != stop_pc_sal.line
6968 || ecs->event_thread->current_symtab != stop_pc_sal.symtab))
6969 {
6970 /* We are at the start of a different line. So stop. Note that
6971 we don't stop if we step into the middle of a different line.
6972 That is said to make things like for (;;) statements work
6973 better. */
6974 if (debug_infrun)
6975 fprintf_unfiltered (gdb_stdlog,
6976 "infrun: stepped to a different line\n");
6977 end_stepping_range (ecs);
6978 return;
6979 }
6980
6981 /* We aren't done stepping.
6982
6983 Optimize by setting the stepping range to the line.
6984 (We might not be in the original line, but if we entered a
6985 new line in mid-statement, we continue stepping. This makes
6986 things like for(;;) statements work better.) */
6987
6988 ecs->event_thread->control.step_range_start = stop_pc_sal.pc;
6989 ecs->event_thread->control.step_range_end = stop_pc_sal.end;
6990 ecs->event_thread->control.may_range_step = 1;
6991 set_step_info (frame, stop_pc_sal);
6992
6993 if (debug_infrun)
6994 fprintf_unfiltered (gdb_stdlog, "infrun: keep going\n");
6995 keep_going (ecs);
6996 }
6997
6998 /* In all-stop mode, if we're currently stepping but have stopped in
6999 some other thread, we may need to switch back to the stepped
7000 thread. Returns true we set the inferior running, false if we left
7001 it stopped (and the event needs further processing). */
7002
7003 static int
7004 switch_back_to_stepped_thread (struct execution_control_state *ecs)
7005 {
7006 if (!target_is_non_stop_p ())
7007 {
7008 struct thread_info *tp;
7009 struct thread_info *stepping_thread;
7010
7011 /* If any thread is blocked on some internal breakpoint, and we
7012 simply need to step over that breakpoint to get it going
7013 again, do that first. */
7014
7015 /* However, if we see an event for the stepping thread, then we
7016 know all other threads have been moved past their breakpoints
7017 already. Let the caller check whether the step is finished,
7018 etc., before deciding to move it past a breakpoint. */
7019 if (ecs->event_thread->control.step_range_end != 0)
7020 return 0;
7021
7022 /* Check if the current thread is blocked on an incomplete
7023 step-over, interrupted by a random signal. */
7024 if (ecs->event_thread->control.trap_expected
7025 && ecs->event_thread->suspend.stop_signal != GDB_SIGNAL_TRAP)
7026 {
7027 if (debug_infrun)
7028 {
7029 fprintf_unfiltered (gdb_stdlog,
7030 "infrun: need to finish step-over of [%s]\n",
7031 target_pid_to_str (ecs->event_thread->ptid));
7032 }
7033 keep_going (ecs);
7034 return 1;
7035 }
7036
7037 /* Check if the current thread is blocked by a single-step
7038 breakpoint of another thread. */
7039 if (ecs->hit_singlestep_breakpoint)
7040 {
7041 if (debug_infrun)
7042 {
7043 fprintf_unfiltered (gdb_stdlog,
7044 "infrun: need to step [%s] over single-step "
7045 "breakpoint\n",
7046 target_pid_to_str (ecs->ptid));
7047 }
7048 keep_going (ecs);
7049 return 1;
7050 }
7051
7052 /* If this thread needs yet another step-over (e.g., stepping
7053 through a delay slot), do it first before moving on to
7054 another thread. */
7055 if (thread_still_needs_step_over (ecs->event_thread))
7056 {
7057 if (debug_infrun)
7058 {
7059 fprintf_unfiltered (gdb_stdlog,
7060 "infrun: thread [%s] still needs step-over\n",
7061 target_pid_to_str (ecs->event_thread->ptid));
7062 }
7063 keep_going (ecs);
7064 return 1;
7065 }
7066
7067 /* If scheduler locking applies even if not stepping, there's no
7068 need to walk over threads. Above we've checked whether the
7069 current thread is stepping. If some other thread not the
7070 event thread is stepping, then it must be that scheduler
7071 locking is not in effect. */
7072 if (schedlock_applies (ecs->event_thread))
7073 return 0;
7074
7075 /* Otherwise, we no longer expect a trap in the current thread.
7076 Clear the trap_expected flag before switching back -- this is
7077 what keep_going does as well, if we call it. */
7078 ecs->event_thread->control.trap_expected = 0;
7079
7080 /* Likewise, clear the signal if it should not be passed. */
7081 if (!signal_program[ecs->event_thread->suspend.stop_signal])
7082 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
7083
7084 /* Do all pending step-overs before actually proceeding with
7085 step/next/etc. */
7086 if (start_step_over ())
7087 {
7088 prepare_to_wait (ecs);
7089 return 1;
7090 }
7091
7092 /* Look for the stepping/nexting thread. */
7093 stepping_thread = NULL;
7094
7095 ALL_NON_EXITED_THREADS (tp)
7096 {
7097 /* Ignore threads of processes the caller is not
7098 resuming. */
7099 if (!sched_multi
7100 && ptid_get_pid (tp->ptid) != ptid_get_pid (ecs->ptid))
7101 continue;
7102
7103 /* When stepping over a breakpoint, we lock all threads
7104 except the one that needs to move past the breakpoint.
7105 If a non-event thread has this set, the "incomplete
7106 step-over" check above should have caught it earlier. */
7107 if (tp->control.trap_expected)
7108 {
7109 internal_error (__FILE__, __LINE__,
7110 "[%s] has inconsistent state: "
7111 "trap_expected=%d\n",
7112 target_pid_to_str (tp->ptid),
7113 tp->control.trap_expected);
7114 }
7115
7116 /* Did we find the stepping thread? */
7117 if (tp->control.step_range_end)
7118 {
7119 /* Yep. There should only one though. */
7120 gdb_assert (stepping_thread == NULL);
7121
7122 /* The event thread is handled at the top, before we
7123 enter this loop. */
7124 gdb_assert (tp != ecs->event_thread);
7125
7126 /* If some thread other than the event thread is
7127 stepping, then scheduler locking can't be in effect,
7128 otherwise we wouldn't have resumed the current event
7129 thread in the first place. */
7130 gdb_assert (!schedlock_applies (tp));
7131
7132 stepping_thread = tp;
7133 }
7134 }
7135
7136 if (stepping_thread != NULL)
7137 {
7138 if (debug_infrun)
7139 fprintf_unfiltered (gdb_stdlog,
7140 "infrun: switching back to stepped thread\n");
7141
7142 if (keep_going_stepped_thread (stepping_thread))
7143 {
7144 prepare_to_wait (ecs);
7145 return 1;
7146 }
7147 }
7148 }
7149
7150 return 0;
7151 }
7152
7153 /* Set a previously stepped thread back to stepping. Returns true on
7154 success, false if the resume is not possible (e.g., the thread
7155 vanished). */
7156
7157 static int
7158 keep_going_stepped_thread (struct thread_info *tp)
7159 {
7160 struct frame_info *frame;
7161 struct execution_control_state ecss;
7162 struct execution_control_state *ecs = &ecss;
7163
7164 /* If the stepping thread exited, then don't try to switch back and
7165 resume it, which could fail in several different ways depending
7166 on the target. Instead, just keep going.
7167
7168 We can find a stepping dead thread in the thread list in two
7169 cases:
7170
7171 - The target supports thread exit events, and when the target
7172 tries to delete the thread from the thread list, inferior_ptid
7173 pointed at the exiting thread. In such case, calling
7174 delete_thread does not really remove the thread from the list;
7175 instead, the thread is left listed, with 'exited' state.
7176
7177 - The target's debug interface does not support thread exit
7178 events, and so we have no idea whatsoever if the previously
7179 stepping thread is still alive. For that reason, we need to
7180 synchronously query the target now. */
7181
7182 if (is_exited (tp->ptid)
7183 || !target_thread_alive (tp->ptid))
7184 {
7185 if (debug_infrun)
7186 fprintf_unfiltered (gdb_stdlog,
7187 "infrun: not resuming previously "
7188 "stepped thread, it has vanished\n");
7189
7190 delete_thread (tp->ptid);
7191 return 0;
7192 }
7193
7194 if (debug_infrun)
7195 fprintf_unfiltered (gdb_stdlog,
7196 "infrun: resuming previously stepped thread\n");
7197
7198 reset_ecs (ecs, tp);
7199 switch_to_thread (tp->ptid);
7200
7201 stop_pc = regcache_read_pc (get_thread_regcache (tp->ptid));
7202 frame = get_current_frame ();
7203
7204 /* If the PC of the thread we were trying to single-step has
7205 changed, then that thread has trapped or been signaled, but the
7206 event has not been reported to GDB yet. Re-poll the target
7207 looking for this particular thread's event (i.e. temporarily
7208 enable schedlock) by:
7209
7210 - setting a break at the current PC
7211 - resuming that particular thread, only (by setting trap
7212 expected)
7213
7214 This prevents us continuously moving the single-step breakpoint
7215 forward, one instruction at a time, overstepping. */
7216
7217 if (stop_pc != tp->prev_pc)
7218 {
7219 ptid_t resume_ptid;
7220
7221 if (debug_infrun)
7222 fprintf_unfiltered (gdb_stdlog,
7223 "infrun: expected thread advanced also (%s -> %s)\n",
7224 paddress (target_gdbarch (), tp->prev_pc),
7225 paddress (target_gdbarch (), stop_pc));
7226
7227 /* Clear the info of the previous step-over, as it's no longer
7228 valid (if the thread was trying to step over a breakpoint, it
7229 has already succeeded). It's what keep_going would do too,
7230 if we called it. Do this before trying to insert the sss
7231 breakpoint, otherwise if we were previously trying to step
7232 over this exact address in another thread, the breakpoint is
7233 skipped. */
7234 clear_step_over_info ();
7235 tp->control.trap_expected = 0;
7236
7237 insert_single_step_breakpoint (get_frame_arch (frame),
7238 get_frame_address_space (frame),
7239 stop_pc);
7240
7241 tp->resumed = 1;
7242 resume_ptid = internal_resume_ptid (tp->control.stepping_command);
7243 do_target_resume (resume_ptid, 0, GDB_SIGNAL_0);
7244 }
7245 else
7246 {
7247 if (debug_infrun)
7248 fprintf_unfiltered (gdb_stdlog,
7249 "infrun: expected thread still hasn't advanced\n");
7250
7251 keep_going_pass_signal (ecs);
7252 }
7253 return 1;
7254 }
7255
7256 /* Is thread TP in the middle of (software or hardware)
7257 single-stepping? (Note the result of this function must never be
7258 passed directly as target_resume's STEP parameter.) */
7259
7260 static int
7261 currently_stepping (struct thread_info *tp)
7262 {
7263 return ((tp->control.step_range_end
7264 && tp->control.step_resume_breakpoint == NULL)
7265 || tp->control.trap_expected
7266 || tp->stepped_breakpoint
7267 || bpstat_should_step ());
7268 }
7269
7270 /* Inferior has stepped into a subroutine call with source code that
7271 we should not step over. Do step to the first line of code in
7272 it. */
7273
7274 static void
7275 handle_step_into_function (struct gdbarch *gdbarch,
7276 struct execution_control_state *ecs)
7277 {
7278 fill_in_stop_func (gdbarch, ecs);
7279
7280 compunit_symtab *cust = find_pc_compunit_symtab (stop_pc);
7281 if (cust != NULL && compunit_language (cust) != language_asm)
7282 ecs->stop_func_start
7283 = gdbarch_skip_prologue_noexcept (gdbarch, ecs->stop_func_start);
7284
7285 symtab_and_line stop_func_sal = find_pc_line (ecs->stop_func_start, 0);
7286 /* Use the step_resume_break to step until the end of the prologue,
7287 even if that involves jumps (as it seems to on the vax under
7288 4.2). */
7289 /* If the prologue ends in the middle of a source line, continue to
7290 the end of that source line (if it is still within the function).
7291 Otherwise, just go to end of prologue. */
7292 if (stop_func_sal.end
7293 && stop_func_sal.pc != ecs->stop_func_start
7294 && stop_func_sal.end < ecs->stop_func_end)
7295 ecs->stop_func_start = stop_func_sal.end;
7296
7297 /* Architectures which require breakpoint adjustment might not be able
7298 to place a breakpoint at the computed address. If so, the test
7299 ``ecs->stop_func_start == stop_pc'' will never succeed. Adjust
7300 ecs->stop_func_start to an address at which a breakpoint may be
7301 legitimately placed.
7302
7303 Note: kevinb/2004-01-19: On FR-V, if this adjustment is not
7304 made, GDB will enter an infinite loop when stepping through
7305 optimized code consisting of VLIW instructions which contain
7306 subinstructions corresponding to different source lines. On
7307 FR-V, it's not permitted to place a breakpoint on any but the
7308 first subinstruction of a VLIW instruction. When a breakpoint is
7309 set, GDB will adjust the breakpoint address to the beginning of
7310 the VLIW instruction. Thus, we need to make the corresponding
7311 adjustment here when computing the stop address. */
7312
7313 if (gdbarch_adjust_breakpoint_address_p (gdbarch))
7314 {
7315 ecs->stop_func_start
7316 = gdbarch_adjust_breakpoint_address (gdbarch,
7317 ecs->stop_func_start);
7318 }
7319
7320 if (ecs->stop_func_start == stop_pc)
7321 {
7322 /* We are already there: stop now. */
7323 end_stepping_range (ecs);
7324 return;
7325 }
7326 else
7327 {
7328 /* Put the step-breakpoint there and go until there. */
7329 symtab_and_line sr_sal;
7330 sr_sal.pc = ecs->stop_func_start;
7331 sr_sal.section = find_pc_overlay (ecs->stop_func_start);
7332 sr_sal.pspace = get_frame_program_space (get_current_frame ());
7333
7334 /* Do not specify what the fp should be when we stop since on
7335 some machines the prologue is where the new fp value is
7336 established. */
7337 insert_step_resume_breakpoint_at_sal (gdbarch, sr_sal, null_frame_id);
7338
7339 /* And make sure stepping stops right away then. */
7340 ecs->event_thread->control.step_range_end
7341 = ecs->event_thread->control.step_range_start;
7342 }
7343 keep_going (ecs);
7344 }
7345
7346 /* Inferior has stepped backward into a subroutine call with source
7347 code that we should not step over. Do step to the beginning of the
7348 last line of code in it. */
7349
7350 static void
7351 handle_step_into_function_backward (struct gdbarch *gdbarch,
7352 struct execution_control_state *ecs)
7353 {
7354 struct compunit_symtab *cust;
7355 struct symtab_and_line stop_func_sal;
7356
7357 fill_in_stop_func (gdbarch, ecs);
7358
7359 cust = find_pc_compunit_symtab (stop_pc);
7360 if (cust != NULL && compunit_language (cust) != language_asm)
7361 ecs->stop_func_start
7362 = gdbarch_skip_prologue_noexcept (gdbarch, ecs->stop_func_start);
7363
7364 stop_func_sal = find_pc_line (stop_pc, 0);
7365
7366 /* OK, we're just going to keep stepping here. */
7367 if (stop_func_sal.pc == stop_pc)
7368 {
7369 /* We're there already. Just stop stepping now. */
7370 end_stepping_range (ecs);
7371 }
7372 else
7373 {
7374 /* Else just reset the step range and keep going.
7375 No step-resume breakpoint, they don't work for
7376 epilogues, which can have multiple entry paths. */
7377 ecs->event_thread->control.step_range_start = stop_func_sal.pc;
7378 ecs->event_thread->control.step_range_end = stop_func_sal.end;
7379 keep_going (ecs);
7380 }
7381 return;
7382 }
7383
7384 /* Insert a "step-resume breakpoint" at SR_SAL with frame ID SR_ID.
7385 This is used to both functions and to skip over code. */
7386
7387 static void
7388 insert_step_resume_breakpoint_at_sal_1 (struct gdbarch *gdbarch,
7389 struct symtab_and_line sr_sal,
7390 struct frame_id sr_id,
7391 enum bptype sr_type)
7392 {
7393 /* There should never be more than one step-resume or longjmp-resume
7394 breakpoint per thread, so we should never be setting a new
7395 step_resume_breakpoint when one is already active. */
7396 gdb_assert (inferior_thread ()->control.step_resume_breakpoint == NULL);
7397 gdb_assert (sr_type == bp_step_resume || sr_type == bp_hp_step_resume);
7398
7399 if (debug_infrun)
7400 fprintf_unfiltered (gdb_stdlog,
7401 "infrun: inserting step-resume breakpoint at %s\n",
7402 paddress (gdbarch, sr_sal.pc));
7403
7404 inferior_thread ()->control.step_resume_breakpoint
7405 = set_momentary_breakpoint (gdbarch, sr_sal, sr_id, sr_type).release ();
7406 }
7407
7408 void
7409 insert_step_resume_breakpoint_at_sal (struct gdbarch *gdbarch,
7410 struct symtab_and_line sr_sal,
7411 struct frame_id sr_id)
7412 {
7413 insert_step_resume_breakpoint_at_sal_1 (gdbarch,
7414 sr_sal, sr_id,
7415 bp_step_resume);
7416 }
7417
7418 /* Insert a "high-priority step-resume breakpoint" at RETURN_FRAME.pc.
7419 This is used to skip a potential signal handler.
7420
7421 This is called with the interrupted function's frame. The signal
7422 handler, when it returns, will resume the interrupted function at
7423 RETURN_FRAME.pc. */
7424
7425 static void
7426 insert_hp_step_resume_breakpoint_at_frame (struct frame_info *return_frame)
7427 {
7428 gdb_assert (return_frame != NULL);
7429
7430 struct gdbarch *gdbarch = get_frame_arch (return_frame);
7431
7432 symtab_and_line sr_sal;
7433 sr_sal.pc = gdbarch_addr_bits_remove (gdbarch, get_frame_pc (return_frame));
7434 sr_sal.section = find_pc_overlay (sr_sal.pc);
7435 sr_sal.pspace = get_frame_program_space (return_frame);
7436
7437 insert_step_resume_breakpoint_at_sal_1 (gdbarch, sr_sal,
7438 get_stack_frame_id (return_frame),
7439 bp_hp_step_resume);
7440 }
7441
7442 /* Insert a "step-resume breakpoint" at the previous frame's PC. This
7443 is used to skip a function after stepping into it (for "next" or if
7444 the called function has no debugging information).
7445
7446 The current function has almost always been reached by single
7447 stepping a call or return instruction. NEXT_FRAME belongs to the
7448 current function, and the breakpoint will be set at the caller's
7449 resume address.
7450
7451 This is a separate function rather than reusing
7452 insert_hp_step_resume_breakpoint_at_frame in order to avoid
7453 get_prev_frame, which may stop prematurely (see the implementation
7454 of frame_unwind_caller_id for an example). */
7455
7456 static void
7457 insert_step_resume_breakpoint_at_caller (struct frame_info *next_frame)
7458 {
7459 /* We shouldn't have gotten here if we don't know where the call site
7460 is. */
7461 gdb_assert (frame_id_p (frame_unwind_caller_id (next_frame)));
7462
7463 struct gdbarch *gdbarch = frame_unwind_caller_arch (next_frame);
7464
7465 symtab_and_line sr_sal;
7466 sr_sal.pc = gdbarch_addr_bits_remove (gdbarch,
7467 frame_unwind_caller_pc (next_frame));
7468 sr_sal.section = find_pc_overlay (sr_sal.pc);
7469 sr_sal.pspace = frame_unwind_program_space (next_frame);
7470
7471 insert_step_resume_breakpoint_at_sal (gdbarch, sr_sal,
7472 frame_unwind_caller_id (next_frame));
7473 }
7474
7475 /* Insert a "longjmp-resume" breakpoint at PC. This is used to set a
7476 new breakpoint at the target of a jmp_buf. The handling of
7477 longjmp-resume uses the same mechanisms used for handling
7478 "step-resume" breakpoints. */
7479
7480 static void
7481 insert_longjmp_resume_breakpoint (struct gdbarch *gdbarch, CORE_ADDR pc)
7482 {
7483 /* There should never be more than one longjmp-resume breakpoint per
7484 thread, so we should never be setting a new
7485 longjmp_resume_breakpoint when one is already active. */
7486 gdb_assert (inferior_thread ()->control.exception_resume_breakpoint == NULL);
7487
7488 if (debug_infrun)
7489 fprintf_unfiltered (gdb_stdlog,
7490 "infrun: inserting longjmp-resume breakpoint at %s\n",
7491 paddress (gdbarch, pc));
7492
7493 inferior_thread ()->control.exception_resume_breakpoint =
7494 set_momentary_breakpoint_at_pc (gdbarch, pc, bp_longjmp_resume).release ();
7495 }
7496
7497 /* Insert an exception resume breakpoint. TP is the thread throwing
7498 the exception. The block B is the block of the unwinder debug hook
7499 function. FRAME is the frame corresponding to the call to this
7500 function. SYM is the symbol of the function argument holding the
7501 target PC of the exception. */
7502
7503 static void
7504 insert_exception_resume_breakpoint (struct thread_info *tp,
7505 const struct block *b,
7506 struct frame_info *frame,
7507 struct symbol *sym)
7508 {
7509 TRY
7510 {
7511 struct block_symbol vsym;
7512 struct value *value;
7513 CORE_ADDR handler;
7514 struct breakpoint *bp;
7515
7516 vsym = lookup_symbol (SYMBOL_LINKAGE_NAME (sym), b, VAR_DOMAIN, NULL);
7517 value = read_var_value (vsym.symbol, vsym.block, frame);
7518 /* If the value was optimized out, revert to the old behavior. */
7519 if (! value_optimized_out (value))
7520 {
7521 handler = value_as_address (value);
7522
7523 if (debug_infrun)
7524 fprintf_unfiltered (gdb_stdlog,
7525 "infrun: exception resume at %lx\n",
7526 (unsigned long) handler);
7527
7528 bp = set_momentary_breakpoint_at_pc (get_frame_arch (frame),
7529 handler,
7530 bp_exception_resume).release ();
7531
7532 /* set_momentary_breakpoint_at_pc invalidates FRAME. */
7533 frame = NULL;
7534
7535 bp->thread = tp->global_num;
7536 inferior_thread ()->control.exception_resume_breakpoint = bp;
7537 }
7538 }
7539 CATCH (e, RETURN_MASK_ERROR)
7540 {
7541 /* We want to ignore errors here. */
7542 }
7543 END_CATCH
7544 }
7545
7546 /* A helper for check_exception_resume that sets an
7547 exception-breakpoint based on a SystemTap probe. */
7548
7549 static void
7550 insert_exception_resume_from_probe (struct thread_info *tp,
7551 const struct bound_probe *probe,
7552 struct frame_info *frame)
7553 {
7554 struct value *arg_value;
7555 CORE_ADDR handler;
7556 struct breakpoint *bp;
7557
7558 arg_value = probe_safe_evaluate_at_pc (frame, 1);
7559 if (!arg_value)
7560 return;
7561
7562 handler = value_as_address (arg_value);
7563
7564 if (debug_infrun)
7565 fprintf_unfiltered (gdb_stdlog,
7566 "infrun: exception resume at %s\n",
7567 paddress (get_objfile_arch (probe->objfile),
7568 handler));
7569
7570 bp = set_momentary_breakpoint_at_pc (get_frame_arch (frame),
7571 handler, bp_exception_resume).release ();
7572 bp->thread = tp->global_num;
7573 inferior_thread ()->control.exception_resume_breakpoint = bp;
7574 }
7575
7576 /* This is called when an exception has been intercepted. Check to
7577 see whether the exception's destination is of interest, and if so,
7578 set an exception resume breakpoint there. */
7579
7580 static void
7581 check_exception_resume (struct execution_control_state *ecs,
7582 struct frame_info *frame)
7583 {
7584 struct bound_probe probe;
7585 struct symbol *func;
7586
7587 /* First see if this exception unwinding breakpoint was set via a
7588 SystemTap probe point. If so, the probe has two arguments: the
7589 CFA and the HANDLER. We ignore the CFA, extract the handler, and
7590 set a breakpoint there. */
7591 probe = find_probe_by_pc (get_frame_pc (frame));
7592 if (probe.probe)
7593 {
7594 insert_exception_resume_from_probe (ecs->event_thread, &probe, frame);
7595 return;
7596 }
7597
7598 func = get_frame_function (frame);
7599 if (!func)
7600 return;
7601
7602 TRY
7603 {
7604 const struct block *b;
7605 struct block_iterator iter;
7606 struct symbol *sym;
7607 int argno = 0;
7608
7609 /* The exception breakpoint is a thread-specific breakpoint on
7610 the unwinder's debug hook, declared as:
7611
7612 void _Unwind_DebugHook (void *cfa, void *handler);
7613
7614 The CFA argument indicates the frame to which control is
7615 about to be transferred. HANDLER is the destination PC.
7616
7617 We ignore the CFA and set a temporary breakpoint at HANDLER.
7618 This is not extremely efficient but it avoids issues in gdb
7619 with computing the DWARF CFA, and it also works even in weird
7620 cases such as throwing an exception from inside a signal
7621 handler. */
7622
7623 b = SYMBOL_BLOCK_VALUE (func);
7624 ALL_BLOCK_SYMBOLS (b, iter, sym)
7625 {
7626 if (!SYMBOL_IS_ARGUMENT (sym))
7627 continue;
7628
7629 if (argno == 0)
7630 ++argno;
7631 else
7632 {
7633 insert_exception_resume_breakpoint (ecs->event_thread,
7634 b, frame, sym);
7635 break;
7636 }
7637 }
7638 }
7639 CATCH (e, RETURN_MASK_ERROR)
7640 {
7641 }
7642 END_CATCH
7643 }
7644
7645 static void
7646 stop_waiting (struct execution_control_state *ecs)
7647 {
7648 if (debug_infrun)
7649 fprintf_unfiltered (gdb_stdlog, "infrun: stop_waiting\n");
7650
7651 /* Let callers know we don't want to wait for the inferior anymore. */
7652 ecs->wait_some_more = 0;
7653
7654 /* If all-stop, but the target is always in non-stop mode, stop all
7655 threads now that we're presenting the stop to the user. */
7656 if (!non_stop && target_is_non_stop_p ())
7657 stop_all_threads ();
7658 }
7659
7660 /* Like keep_going, but passes the signal to the inferior, even if the
7661 signal is set to nopass. */
7662
7663 static void
7664 keep_going_pass_signal (struct execution_control_state *ecs)
7665 {
7666 /* Make sure normal_stop is called if we get a QUIT handled before
7667 reaching resume. */
7668 struct cleanup *old_cleanups = make_cleanup (resume_cleanups, 0);
7669
7670 gdb_assert (ptid_equal (ecs->event_thread->ptid, inferior_ptid));
7671 gdb_assert (!ecs->event_thread->resumed);
7672
7673 /* Save the pc before execution, to compare with pc after stop. */
7674 ecs->event_thread->prev_pc
7675 = regcache_read_pc (get_thread_regcache (ecs->ptid));
7676
7677 if (ecs->event_thread->control.trap_expected)
7678 {
7679 struct thread_info *tp = ecs->event_thread;
7680
7681 if (debug_infrun)
7682 fprintf_unfiltered (gdb_stdlog,
7683 "infrun: %s has trap_expected set, "
7684 "resuming to collect trap\n",
7685 target_pid_to_str (tp->ptid));
7686
7687 /* We haven't yet gotten our trap, and either: intercepted a
7688 non-signal event (e.g., a fork); or took a signal which we
7689 are supposed to pass through to the inferior. Simply
7690 continue. */
7691 discard_cleanups (old_cleanups);
7692 resume (ecs->event_thread->suspend.stop_signal);
7693 }
7694 else if (step_over_info_valid_p ())
7695 {
7696 /* Another thread is stepping over a breakpoint in-line. If
7697 this thread needs a step-over too, queue the request. In
7698 either case, this resume must be deferred for later. */
7699 struct thread_info *tp = ecs->event_thread;
7700
7701 if (ecs->hit_singlestep_breakpoint
7702 || thread_still_needs_step_over (tp))
7703 {
7704 if (debug_infrun)
7705 fprintf_unfiltered (gdb_stdlog,
7706 "infrun: step-over already in progress: "
7707 "step-over for %s deferred\n",
7708 target_pid_to_str (tp->ptid));
7709 thread_step_over_chain_enqueue (tp);
7710 }
7711 else
7712 {
7713 if (debug_infrun)
7714 fprintf_unfiltered (gdb_stdlog,
7715 "infrun: step-over in progress: "
7716 "resume of %s deferred\n",
7717 target_pid_to_str (tp->ptid));
7718 }
7719
7720 discard_cleanups (old_cleanups);
7721 }
7722 else
7723 {
7724 struct regcache *regcache = get_current_regcache ();
7725 int remove_bp;
7726 int remove_wps;
7727 step_over_what step_what;
7728
7729 /* Either the trap was not expected, but we are continuing
7730 anyway (if we got a signal, the user asked it be passed to
7731 the child)
7732 -- or --
7733 We got our expected trap, but decided we should resume from
7734 it.
7735
7736 We're going to run this baby now!
7737
7738 Note that insert_breakpoints won't try to re-insert
7739 already inserted breakpoints. Therefore, we don't
7740 care if breakpoints were already inserted, or not. */
7741
7742 /* If we need to step over a breakpoint, and we're not using
7743 displaced stepping to do so, insert all breakpoints
7744 (watchpoints, etc.) but the one we're stepping over, step one
7745 instruction, and then re-insert the breakpoint when that step
7746 is finished. */
7747
7748 step_what = thread_still_needs_step_over (ecs->event_thread);
7749
7750 remove_bp = (ecs->hit_singlestep_breakpoint
7751 || (step_what & STEP_OVER_BREAKPOINT));
7752 remove_wps = (step_what & STEP_OVER_WATCHPOINT);
7753
7754 /* We can't use displaced stepping if we need to step past a
7755 watchpoint. The instruction copied to the scratch pad would
7756 still trigger the watchpoint. */
7757 if (remove_bp
7758 && (remove_wps || !use_displaced_stepping (ecs->event_thread)))
7759 {
7760 set_step_over_info (regcache->aspace (),
7761 regcache_read_pc (regcache), remove_wps,
7762 ecs->event_thread->global_num);
7763 }
7764 else if (remove_wps)
7765 set_step_over_info (NULL, 0, remove_wps, -1);
7766
7767 /* If we now need to do an in-line step-over, we need to stop
7768 all other threads. Note this must be done before
7769 insert_breakpoints below, because that removes the breakpoint
7770 we're about to step over, otherwise other threads could miss
7771 it. */
7772 if (step_over_info_valid_p () && target_is_non_stop_p ())
7773 stop_all_threads ();
7774
7775 /* Stop stepping if inserting breakpoints fails. */
7776 TRY
7777 {
7778 insert_breakpoints ();
7779 }
7780 CATCH (e, RETURN_MASK_ERROR)
7781 {
7782 exception_print (gdb_stderr, e);
7783 stop_waiting (ecs);
7784 discard_cleanups (old_cleanups);
7785 return;
7786 }
7787 END_CATCH
7788
7789 ecs->event_thread->control.trap_expected = (remove_bp || remove_wps);
7790
7791 discard_cleanups (old_cleanups);
7792 resume (ecs->event_thread->suspend.stop_signal);
7793 }
7794
7795 prepare_to_wait (ecs);
7796 }
7797
7798 /* Called when we should continue running the inferior, because the
7799 current event doesn't cause a user visible stop. This does the
7800 resuming part; waiting for the next event is done elsewhere. */
7801
7802 static void
7803 keep_going (struct execution_control_state *ecs)
7804 {
7805 if (ecs->event_thread->control.trap_expected
7806 && ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
7807 ecs->event_thread->control.trap_expected = 0;
7808
7809 if (!signal_program[ecs->event_thread->suspend.stop_signal])
7810 ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
7811 keep_going_pass_signal (ecs);
7812 }
7813
7814 /* This function normally comes after a resume, before
7815 handle_inferior_event exits. It takes care of any last bits of
7816 housekeeping, and sets the all-important wait_some_more flag. */
7817
7818 static void
7819 prepare_to_wait (struct execution_control_state *ecs)
7820 {
7821 if (debug_infrun)
7822 fprintf_unfiltered (gdb_stdlog, "infrun: prepare_to_wait\n");
7823
7824 ecs->wait_some_more = 1;
7825
7826 if (!target_is_async_p ())
7827 mark_infrun_async_event_handler ();
7828 }
7829
7830 /* We are done with the step range of a step/next/si/ni command.
7831 Called once for each n of a "step n" operation. */
7832
7833 static void
7834 end_stepping_range (struct execution_control_state *ecs)
7835 {
7836 ecs->event_thread->control.stop_step = 1;
7837 stop_waiting (ecs);
7838 }
7839
7840 /* Several print_*_reason functions to print why the inferior has stopped.
7841 We always print something when the inferior exits, or receives a signal.
7842 The rest of the cases are dealt with later on in normal_stop and
7843 print_it_typical. Ideally there should be a call to one of these
7844 print_*_reason functions functions from handle_inferior_event each time
7845 stop_waiting is called.
7846
7847 Note that we don't call these directly, instead we delegate that to
7848 the interpreters, through observers. Interpreters then call these
7849 with whatever uiout is right. */
7850
7851 void
7852 print_end_stepping_range_reason (struct ui_out *uiout)
7853 {
7854 /* For CLI-like interpreters, print nothing. */
7855
7856 if (uiout->is_mi_like_p ())
7857 {
7858 uiout->field_string ("reason",
7859 async_reason_lookup (EXEC_ASYNC_END_STEPPING_RANGE));
7860 }
7861 }
7862
7863 void
7864 print_signal_exited_reason (struct ui_out *uiout, enum gdb_signal siggnal)
7865 {
7866 annotate_signalled ();
7867 if (uiout->is_mi_like_p ())
7868 uiout->field_string
7869 ("reason", async_reason_lookup (EXEC_ASYNC_EXITED_SIGNALLED));
7870 uiout->text ("\nProgram terminated with signal ");
7871 annotate_signal_name ();
7872 uiout->field_string ("signal-name",
7873 gdb_signal_to_name (siggnal));
7874 annotate_signal_name_end ();
7875 uiout->text (", ");
7876 annotate_signal_string ();
7877 uiout->field_string ("signal-meaning",
7878 gdb_signal_to_string (siggnal));
7879 annotate_signal_string_end ();
7880 uiout->text (".\n");
7881 uiout->text ("The program no longer exists.\n");
7882 }
7883
7884 void
7885 print_exited_reason (struct ui_out *uiout, int exitstatus)
7886 {
7887 struct inferior *inf = current_inferior ();
7888 const char *pidstr = target_pid_to_str (pid_to_ptid (inf->pid));
7889
7890 annotate_exited (exitstatus);
7891 if (exitstatus)
7892 {
7893 if (uiout->is_mi_like_p ())
7894 uiout->field_string ("reason", async_reason_lookup (EXEC_ASYNC_EXITED));
7895 uiout->text ("[Inferior ");
7896 uiout->text (plongest (inf->num));
7897 uiout->text (" (");
7898 uiout->text (pidstr);
7899 uiout->text (") exited with code ");
7900 uiout->field_fmt ("exit-code", "0%o", (unsigned int) exitstatus);
7901 uiout->text ("]\n");
7902 }
7903 else
7904 {
7905 if (uiout->is_mi_like_p ())
7906 uiout->field_string
7907 ("reason", async_reason_lookup (EXEC_ASYNC_EXITED_NORMALLY));
7908 uiout->text ("[Inferior ");
7909 uiout->text (plongest (inf->num));
7910 uiout->text (" (");
7911 uiout->text (pidstr);
7912 uiout->text (") exited normally]\n");
7913 }
7914 }
7915
7916 /* Some targets/architectures can do extra processing/display of
7917 segmentation faults. E.g., Intel MPX boundary faults.
7918 Call the architecture dependent function to handle the fault. */
7919
7920 static void
7921 handle_segmentation_fault (struct ui_out *uiout)
7922 {
7923 struct regcache *regcache = get_current_regcache ();
7924 struct gdbarch *gdbarch = regcache->arch ();
7925
7926 if (gdbarch_handle_segmentation_fault_p (gdbarch))
7927 gdbarch_handle_segmentation_fault (gdbarch, uiout);
7928 }
7929
7930 void
7931 print_signal_received_reason (struct ui_out *uiout, enum gdb_signal siggnal)
7932 {
7933 struct thread_info *thr = inferior_thread ();
7934
7935 annotate_signal ();
7936
7937 if (uiout->is_mi_like_p ())
7938 ;
7939 else if (show_thread_that_caused_stop ())
7940 {
7941 const char *name;
7942
7943 uiout->text ("\nThread ");
7944 uiout->field_fmt ("thread-id", "%s", print_thread_id (thr));
7945
7946 name = thr->name != NULL ? thr->name : target_thread_name (thr);
7947 if (name != NULL)
7948 {
7949 uiout->text (" \"");
7950 uiout->field_fmt ("name", "%s", name);
7951 uiout->text ("\"");
7952 }
7953 }
7954 else
7955 uiout->text ("\nProgram");
7956
7957 if (siggnal == GDB_SIGNAL_0 && !uiout->is_mi_like_p ())
7958 uiout->text (" stopped");
7959 else
7960 {
7961 uiout->text (" received signal ");
7962 annotate_signal_name ();
7963 if (uiout->is_mi_like_p ())
7964 uiout->field_string
7965 ("reason", async_reason_lookup (EXEC_ASYNC_SIGNAL_RECEIVED));
7966 uiout->field_string ("signal-name", gdb_signal_to_name (siggnal));
7967 annotate_signal_name_end ();
7968 uiout->text (", ");
7969 annotate_signal_string ();
7970 uiout->field_string ("signal-meaning", gdb_signal_to_string (siggnal));
7971
7972 if (siggnal == GDB_SIGNAL_SEGV)
7973 handle_segmentation_fault (uiout);
7974
7975 annotate_signal_string_end ();
7976 }
7977 uiout->text (".\n");
7978 }
7979
7980 void
7981 print_no_history_reason (struct ui_out *uiout)
7982 {
7983 uiout->text ("\nNo more reverse-execution history.\n");
7984 }
7985
7986 /* Print current location without a level number, if we have changed
7987 functions or hit a breakpoint. Print source line if we have one.
7988 bpstat_print contains the logic deciding in detail what to print,
7989 based on the event(s) that just occurred. */
7990
7991 static void
7992 print_stop_location (struct target_waitstatus *ws)
7993 {
7994 int bpstat_ret;
7995 enum print_what source_flag;
7996 int do_frame_printing = 1;
7997 struct thread_info *tp = inferior_thread ();
7998
7999 bpstat_ret = bpstat_print (tp->control.stop_bpstat, ws->kind);
8000 switch (bpstat_ret)
8001 {
8002 case PRINT_UNKNOWN:
8003 /* FIXME: cagney/2002-12-01: Given that a frame ID does (or
8004 should) carry around the function and does (or should) use
8005 that when doing a frame comparison. */
8006 if (tp->control.stop_step
8007 && frame_id_eq (tp->control.step_frame_id,
8008 get_frame_id (get_current_frame ()))
8009 && tp->control.step_start_function == find_pc_function (stop_pc))
8010 {
8011 /* Finished step, just print source line. */
8012 source_flag = SRC_LINE;
8013 }
8014 else
8015 {
8016 /* Print location and source line. */
8017 source_flag = SRC_AND_LOC;
8018 }
8019 break;
8020 case PRINT_SRC_AND_LOC:
8021 /* Print location and source line. */
8022 source_flag = SRC_AND_LOC;
8023 break;
8024 case PRINT_SRC_ONLY:
8025 source_flag = SRC_LINE;
8026 break;
8027 case PRINT_NOTHING:
8028 /* Something bogus. */
8029 source_flag = SRC_LINE;
8030 do_frame_printing = 0;
8031 break;
8032 default:
8033 internal_error (__FILE__, __LINE__, _("Unknown value."));
8034 }
8035
8036 /* The behavior of this routine with respect to the source
8037 flag is:
8038 SRC_LINE: Print only source line
8039 LOCATION: Print only location
8040 SRC_AND_LOC: Print location and source line. */
8041 if (do_frame_printing)
8042 print_stack_frame (get_selected_frame (NULL), 0, source_flag, 1);
8043 }
8044
8045 /* See infrun.h. */
8046
8047 void
8048 print_stop_event (struct ui_out *uiout)
8049 {
8050 struct target_waitstatus last;
8051 ptid_t last_ptid;
8052 struct thread_info *tp;
8053
8054 get_last_target_status (&last_ptid, &last);
8055
8056 {
8057 scoped_restore save_uiout = make_scoped_restore (&current_uiout, uiout);
8058
8059 print_stop_location (&last);
8060
8061 /* Display the auto-display expressions. */
8062 do_displays ();
8063 }
8064
8065 tp = inferior_thread ();
8066 if (tp->thread_fsm != NULL
8067 && thread_fsm_finished_p (tp->thread_fsm))
8068 {
8069 struct return_value_info *rv;
8070
8071 rv = thread_fsm_return_value (tp->thread_fsm);
8072 if (rv != NULL)
8073 print_return_value (uiout, rv);
8074 }
8075 }
8076
8077 /* See infrun.h. */
8078
8079 void
8080 maybe_remove_breakpoints (void)
8081 {
8082 if (!breakpoints_should_be_inserted_now () && target_has_execution)
8083 {
8084 if (remove_breakpoints ())
8085 {
8086 target_terminal::ours_for_output ();
8087 printf_filtered (_("Cannot remove breakpoints because "
8088 "program is no longer writable.\nFurther "
8089 "execution is probably impossible.\n"));
8090 }
8091 }
8092 }
8093
8094 /* The execution context that just caused a normal stop. */
8095
8096 struct stop_context
8097 {
8098 /* The stop ID. */
8099 ULONGEST stop_id;
8100
8101 /* The event PTID. */
8102
8103 ptid_t ptid;
8104
8105 /* If stopp for a thread event, this is the thread that caused the
8106 stop. */
8107 struct thread_info *thread;
8108
8109 /* The inferior that caused the stop. */
8110 int inf_num;
8111 };
8112
8113 /* Returns a new stop context. If stopped for a thread event, this
8114 takes a strong reference to the thread. */
8115
8116 static struct stop_context *
8117 save_stop_context (void)
8118 {
8119 struct stop_context *sc = XNEW (struct stop_context);
8120
8121 sc->stop_id = get_stop_id ();
8122 sc->ptid = inferior_ptid;
8123 sc->inf_num = current_inferior ()->num;
8124
8125 if (!ptid_equal (inferior_ptid, null_ptid))
8126 {
8127 /* Take a strong reference so that the thread can't be deleted
8128 yet. */
8129 sc->thread = inferior_thread ();
8130 sc->thread->incref ();
8131 }
8132 else
8133 sc->thread = NULL;
8134
8135 return sc;
8136 }
8137
8138 /* Release a stop context previously created with save_stop_context.
8139 Releases the strong reference to the thread as well. */
8140
8141 static void
8142 release_stop_context_cleanup (void *arg)
8143 {
8144 struct stop_context *sc = (struct stop_context *) arg;
8145
8146 if (sc->thread != NULL)
8147 sc->thread->decref ();
8148 xfree (sc);
8149 }
8150
8151 /* Return true if the current context no longer matches the saved stop
8152 context. */
8153
8154 static int
8155 stop_context_changed (struct stop_context *prev)
8156 {
8157 if (!ptid_equal (prev->ptid, inferior_ptid))
8158 return 1;
8159 if (prev->inf_num != current_inferior ()->num)
8160 return 1;
8161 if (prev->thread != NULL && prev->thread->state != THREAD_STOPPED)
8162 return 1;
8163 if (get_stop_id () != prev->stop_id)
8164 return 1;
8165 return 0;
8166 }
8167
8168 /* See infrun.h. */
8169
8170 int
8171 normal_stop (void)
8172 {
8173 struct target_waitstatus last;
8174 ptid_t last_ptid;
8175 struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
8176 ptid_t pid_ptid;
8177
8178 get_last_target_status (&last_ptid, &last);
8179
8180 new_stop_id ();
8181
8182 /* If an exception is thrown from this point on, make sure to
8183 propagate GDB's knowledge of the executing state to the
8184 frontend/user running state. A QUIT is an easy exception to see
8185 here, so do this before any filtered output. */
8186 if (!non_stop)
8187 make_cleanup (finish_thread_state_cleanup, &minus_one_ptid);
8188 else if (last.kind == TARGET_WAITKIND_SIGNALLED
8189 || last.kind == TARGET_WAITKIND_EXITED)
8190 {
8191 /* On some targets, we may still have live threads in the
8192 inferior when we get a process exit event. E.g., for
8193 "checkpoint", when the current checkpoint/fork exits,
8194 linux-fork.c automatically switches to another fork from
8195 within target_mourn_inferior. */
8196 if (!ptid_equal (inferior_ptid, null_ptid))
8197 {
8198 pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
8199 make_cleanup (finish_thread_state_cleanup, &pid_ptid);
8200 }
8201 }
8202 else if (last.kind != TARGET_WAITKIND_NO_RESUMED)
8203 make_cleanup (finish_thread_state_cleanup, &inferior_ptid);
8204
8205 /* As we're presenting a stop, and potentially removing breakpoints,
8206 update the thread list so we can tell whether there are threads
8207 running on the target. With target remote, for example, we can
8208 only learn about new threads when we explicitly update the thread
8209 list. Do this before notifying the interpreters about signal
8210 stops, end of stepping ranges, etc., so that the "new thread"
8211 output is emitted before e.g., "Program received signal FOO",
8212 instead of after. */
8213 update_thread_list ();
8214
8215 if (last.kind == TARGET_WAITKIND_STOPPED && stopped_by_random_signal)
8216 observer_notify_signal_received (inferior_thread ()->suspend.stop_signal);
8217
8218 /* As with the notification of thread events, we want to delay
8219 notifying the user that we've switched thread context until
8220 the inferior actually stops.
8221
8222 There's no point in saying anything if the inferior has exited.
8223 Note that SIGNALLED here means "exited with a signal", not
8224 "received a signal".
8225
8226 Also skip saying anything in non-stop mode. In that mode, as we
8227 don't want GDB to switch threads behind the user's back, to avoid
8228 races where the user is typing a command to apply to thread x,
8229 but GDB switches to thread y before the user finishes entering
8230 the command, fetch_inferior_event installs a cleanup to restore
8231 the current thread back to the thread the user had selected right
8232 after this event is handled, so we're not really switching, only
8233 informing of a stop. */
8234 if (!non_stop
8235 && !ptid_equal (previous_inferior_ptid, inferior_ptid)
8236 && target_has_execution
8237 && last.kind != TARGET_WAITKIND_SIGNALLED
8238 && last.kind != TARGET_WAITKIND_EXITED
8239 && last.kind != TARGET_WAITKIND_NO_RESUMED)
8240 {
8241 SWITCH_THRU_ALL_UIS ()
8242 {
8243 target_terminal::ours_for_output ();
8244 printf_filtered (_("[Switching to %s]\n"),
8245 target_pid_to_str (inferior_ptid));
8246 annotate_thread_changed ();
8247 }
8248 previous_inferior_ptid = inferior_ptid;
8249 }
8250
8251 if (last.kind == TARGET_WAITKIND_NO_RESUMED)
8252 {
8253 SWITCH_THRU_ALL_UIS ()
8254 if (current_ui->prompt_state == PROMPT_BLOCKED)
8255 {
8256 target_terminal::ours_for_output ();
8257 printf_filtered (_("No unwaited-for children left.\n"));
8258 }
8259 }
8260
8261 /* Note: this depends on the update_thread_list call above. */
8262 maybe_remove_breakpoints ();
8263
8264 /* If an auto-display called a function and that got a signal,
8265 delete that auto-display to avoid an infinite recursion. */
8266
8267 if (stopped_by_random_signal)
8268 disable_current_display ();
8269
8270 SWITCH_THRU_ALL_UIS ()
8271 {
8272 async_enable_stdin ();
8273 }
8274
8275 /* Let the user/frontend see the threads as stopped. */
8276 do_cleanups (old_chain);
8277
8278 /* Select innermost stack frame - i.e., current frame is frame 0,
8279 and current location is based on that. Handle the case where the
8280 dummy call is returning after being stopped. E.g. the dummy call
8281 previously hit a breakpoint. (If the dummy call returns
8282 normally, we won't reach here.) Do this before the stop hook is
8283 run, so that it doesn't get to see the temporary dummy frame,
8284 which is not where we'll present the stop. */
8285 if (has_stack_frames ())
8286 {
8287 if (stop_stack_dummy == STOP_STACK_DUMMY)
8288 {
8289 /* Pop the empty frame that contains the stack dummy. This
8290 also restores inferior state prior to the call (struct
8291 infcall_suspend_state). */
8292 struct frame_info *frame = get_current_frame ();
8293
8294 gdb_assert (get_frame_type (frame) == DUMMY_FRAME);
8295 frame_pop (frame);
8296 /* frame_pop calls reinit_frame_cache as the last thing it
8297 does which means there's now no selected frame. */
8298 }
8299
8300 select_frame (get_current_frame ());
8301
8302 /* Set the current source location. */
8303 set_current_sal_from_frame (get_current_frame ());
8304 }
8305
8306 /* Look up the hook_stop and run it (CLI internally handles problem
8307 of stop_command's pre-hook not existing). */
8308 if (stop_command != NULL)
8309 {
8310 struct stop_context *saved_context = save_stop_context ();
8311 struct cleanup *old_chain
8312 = make_cleanup (release_stop_context_cleanup, saved_context);
8313
8314 TRY
8315 {
8316 execute_cmd_pre_hook (stop_command);
8317 }
8318 CATCH (ex, RETURN_MASK_ALL)
8319 {
8320 exception_fprintf (gdb_stderr, ex,
8321 "Error while running hook_stop:\n");
8322 }
8323 END_CATCH
8324
8325 /* If the stop hook resumes the target, then there's no point in
8326 trying to notify about the previous stop; its context is
8327 gone. Likewise if the command switches thread or inferior --
8328 the observers would print a stop for the wrong
8329 thread/inferior. */
8330 if (stop_context_changed (saved_context))
8331 {
8332 do_cleanups (old_chain);
8333 return 1;
8334 }
8335 do_cleanups (old_chain);
8336 }
8337
8338 /* Notify observers about the stop. This is where the interpreters
8339 print the stop event. */
8340 if (!ptid_equal (inferior_ptid, null_ptid))
8341 observer_notify_normal_stop (inferior_thread ()->control.stop_bpstat,
8342 stop_print_frame);
8343 else
8344 observer_notify_normal_stop (NULL, stop_print_frame);
8345
8346 annotate_stopped ();
8347
8348 if (target_has_execution)
8349 {
8350 if (last.kind != TARGET_WAITKIND_SIGNALLED
8351 && last.kind != TARGET_WAITKIND_EXITED)
8352 /* Delete the breakpoint we stopped at, if it wants to be deleted.
8353 Delete any breakpoint that is to be deleted at the next stop. */
8354 breakpoint_auto_delete (inferior_thread ()->control.stop_bpstat);
8355 }
8356
8357 /* Try to get rid of automatically added inferiors that are no
8358 longer needed. Keeping those around slows down things linearly.
8359 Note that this never removes the current inferior. */
8360 prune_inferiors ();
8361
8362 return 0;
8363 }
8364 \f
8365 int
8366 signal_stop_state (int signo)
8367 {
8368 return signal_stop[signo];
8369 }
8370
8371 int
8372 signal_print_state (int signo)
8373 {
8374 return signal_print[signo];
8375 }
8376
8377 int
8378 signal_pass_state (int signo)
8379 {
8380 return signal_program[signo];
8381 }
8382
8383 static void
8384 signal_cache_update (int signo)
8385 {
8386 if (signo == -1)
8387 {
8388 for (signo = 0; signo < (int) GDB_SIGNAL_LAST; signo++)
8389 signal_cache_update (signo);
8390
8391 return;
8392 }
8393
8394 signal_pass[signo] = (signal_stop[signo] == 0
8395 && signal_print[signo] == 0
8396 && signal_program[signo] == 1
8397 && signal_catch[signo] == 0);
8398 }
8399
8400 int
8401 signal_stop_update (int signo, int state)
8402 {
8403 int ret = signal_stop[signo];
8404
8405 signal_stop[signo] = state;
8406 signal_cache_update (signo);
8407 return ret;
8408 }
8409
8410 int
8411 signal_print_update (int signo, int state)
8412 {
8413 int ret = signal_print[signo];
8414
8415 signal_print[signo] = state;
8416 signal_cache_update (signo);
8417 return ret;
8418 }
8419
8420 int
8421 signal_pass_update (int signo, int state)
8422 {
8423 int ret = signal_program[signo];
8424
8425 signal_program[signo] = state;
8426 signal_cache_update (signo);
8427 return ret;
8428 }
8429
8430 /* Update the global 'signal_catch' from INFO and notify the
8431 target. */
8432
8433 void
8434 signal_catch_update (const unsigned int *info)
8435 {
8436 int i;
8437
8438 for (i = 0; i < GDB_SIGNAL_LAST; ++i)
8439 signal_catch[i] = info[i] > 0;
8440 signal_cache_update (-1);
8441 target_pass_signals ((int) GDB_SIGNAL_LAST, signal_pass);
8442 }
8443
8444 static void
8445 sig_print_header (void)
8446 {
8447 printf_filtered (_("Signal Stop\tPrint\tPass "
8448 "to program\tDescription\n"));
8449 }
8450
8451 static void
8452 sig_print_info (enum gdb_signal oursig)
8453 {
8454 const char *name = gdb_signal_to_name (oursig);
8455 int name_padding = 13 - strlen (name);
8456
8457 if (name_padding <= 0)
8458 name_padding = 0;
8459
8460 printf_filtered ("%s", name);
8461 printf_filtered ("%*.*s ", name_padding, name_padding, " ");
8462 printf_filtered ("%s\t", signal_stop[oursig] ? "Yes" : "No");
8463 printf_filtered ("%s\t", signal_print[oursig] ? "Yes" : "No");
8464 printf_filtered ("%s\t\t", signal_program[oursig] ? "Yes" : "No");
8465 printf_filtered ("%s\n", gdb_signal_to_string (oursig));
8466 }
8467
8468 /* Specify how various signals in the inferior should be handled. */
8469
8470 static void
8471 handle_command (char *args, int from_tty)
8472 {
8473 int digits, wordlen;
8474 int sigfirst, signum, siglast;
8475 enum gdb_signal oursig;
8476 int allsigs;
8477 int nsigs;
8478 unsigned char *sigs;
8479
8480 if (args == NULL)
8481 {
8482 error_no_arg (_("signal to handle"));
8483 }
8484
8485 /* Allocate and zero an array of flags for which signals to handle. */
8486
8487 nsigs = (int) GDB_SIGNAL_LAST;
8488 sigs = (unsigned char *) alloca (nsigs);
8489 memset (sigs, 0, nsigs);
8490
8491 /* Break the command line up into args. */
8492
8493 gdb_argv built_argv (args);
8494
8495 /* Walk through the args, looking for signal oursigs, signal names, and
8496 actions. Signal numbers and signal names may be interspersed with
8497 actions, with the actions being performed for all signals cumulatively
8498 specified. Signal ranges can be specified as <LOW>-<HIGH>. */
8499
8500 for (char *arg : built_argv)
8501 {
8502 wordlen = strlen (arg);
8503 for (digits = 0; isdigit (arg[digits]); digits++)
8504 {;
8505 }
8506 allsigs = 0;
8507 sigfirst = siglast = -1;
8508
8509 if (wordlen >= 1 && !strncmp (arg, "all", wordlen))
8510 {
8511 /* Apply action to all signals except those used by the
8512 debugger. Silently skip those. */
8513 allsigs = 1;
8514 sigfirst = 0;
8515 siglast = nsigs - 1;
8516 }
8517 else if (wordlen >= 1 && !strncmp (arg, "stop", wordlen))
8518 {
8519 SET_SIGS (nsigs, sigs, signal_stop);
8520 SET_SIGS (nsigs, sigs, signal_print);
8521 }
8522 else if (wordlen >= 1 && !strncmp (arg, "ignore", wordlen))
8523 {
8524 UNSET_SIGS (nsigs, sigs, signal_program);
8525 }
8526 else if (wordlen >= 2 && !strncmp (arg, "print", wordlen))
8527 {
8528 SET_SIGS (nsigs, sigs, signal_print);
8529 }
8530 else if (wordlen >= 2 && !strncmp (arg, "pass", wordlen))
8531 {
8532 SET_SIGS (nsigs, sigs, signal_program);
8533 }
8534 else if (wordlen >= 3 && !strncmp (arg, "nostop", wordlen))
8535 {
8536 UNSET_SIGS (nsigs, sigs, signal_stop);
8537 }
8538 else if (wordlen >= 3 && !strncmp (arg, "noignore", wordlen))
8539 {
8540 SET_SIGS (nsigs, sigs, signal_program);
8541 }
8542 else if (wordlen >= 4 && !strncmp (arg, "noprint", wordlen))
8543 {
8544 UNSET_SIGS (nsigs, sigs, signal_print);
8545 UNSET_SIGS (nsigs, sigs, signal_stop);
8546 }
8547 else if (wordlen >= 4 && !strncmp (arg, "nopass", wordlen))
8548 {
8549 UNSET_SIGS (nsigs, sigs, signal_program);
8550 }
8551 else if (digits > 0)
8552 {
8553 /* It is numeric. The numeric signal refers to our own
8554 internal signal numbering from target.h, not to host/target
8555 signal number. This is a feature; users really should be
8556 using symbolic names anyway, and the common ones like
8557 SIGHUP, SIGINT, SIGALRM, etc. will work right anyway. */
8558
8559 sigfirst = siglast = (int)
8560 gdb_signal_from_command (atoi (arg));
8561 if (arg[digits] == '-')
8562 {
8563 siglast = (int)
8564 gdb_signal_from_command (atoi (arg + digits + 1));
8565 }
8566 if (sigfirst > siglast)
8567 {
8568 /* Bet he didn't figure we'd think of this case... */
8569 signum = sigfirst;
8570 sigfirst = siglast;
8571 siglast = signum;
8572 }
8573 }
8574 else
8575 {
8576 oursig = gdb_signal_from_name (arg);
8577 if (oursig != GDB_SIGNAL_UNKNOWN)
8578 {
8579 sigfirst = siglast = (int) oursig;
8580 }
8581 else
8582 {
8583 /* Not a number and not a recognized flag word => complain. */
8584 error (_("Unrecognized or ambiguous flag word: \"%s\"."), arg);
8585 }
8586 }
8587
8588 /* If any signal numbers or symbol names were found, set flags for
8589 which signals to apply actions to. */
8590
8591 for (signum = sigfirst; signum >= 0 && signum <= siglast; signum++)
8592 {
8593 switch ((enum gdb_signal) signum)
8594 {
8595 case GDB_SIGNAL_TRAP:
8596 case GDB_SIGNAL_INT:
8597 if (!allsigs && !sigs[signum])
8598 {
8599 if (query (_("%s is used by the debugger.\n\
8600 Are you sure you want to change it? "),
8601 gdb_signal_to_name ((enum gdb_signal) signum)))
8602 {
8603 sigs[signum] = 1;
8604 }
8605 else
8606 {
8607 printf_unfiltered (_("Not confirmed, unchanged.\n"));
8608 gdb_flush (gdb_stdout);
8609 }
8610 }
8611 break;
8612 case GDB_SIGNAL_0:
8613 case GDB_SIGNAL_DEFAULT:
8614 case GDB_SIGNAL_UNKNOWN:
8615 /* Make sure that "all" doesn't print these. */
8616 break;
8617 default:
8618 sigs[signum] = 1;
8619 break;
8620 }
8621 }
8622 }
8623
8624 for (signum = 0; signum < nsigs; signum++)
8625 if (sigs[signum])
8626 {
8627 signal_cache_update (-1);
8628 target_pass_signals ((int) GDB_SIGNAL_LAST, signal_pass);
8629 target_program_signals ((int) GDB_SIGNAL_LAST, signal_program);
8630
8631 if (from_tty)
8632 {
8633 /* Show the results. */
8634 sig_print_header ();
8635 for (; signum < nsigs; signum++)
8636 if (sigs[signum])
8637 sig_print_info ((enum gdb_signal) signum);
8638 }
8639
8640 break;
8641 }
8642 }
8643
8644 /* Complete the "handle" command. */
8645
8646 static void
8647 handle_completer (struct cmd_list_element *ignore,
8648 completion_tracker &tracker,
8649 const char *text, const char *word)
8650 {
8651 static const char * const keywords[] =
8652 {
8653 "all",
8654 "stop",
8655 "ignore",
8656 "print",
8657 "pass",
8658 "nostop",
8659 "noignore",
8660 "noprint",
8661 "nopass",
8662 NULL,
8663 };
8664
8665 signal_completer (ignore, tracker, text, word);
8666 complete_on_enum (tracker, keywords, word, word);
8667 }
8668
8669 enum gdb_signal
8670 gdb_signal_from_command (int num)
8671 {
8672 if (num >= 1 && num <= 15)
8673 return (enum gdb_signal) num;
8674 error (_("Only signals 1-15 are valid as numeric signals.\n\
8675 Use \"info signals\" for a list of symbolic signals."));
8676 }
8677
8678 /* Print current contents of the tables set by the handle command.
8679 It is possible we should just be printing signals actually used
8680 by the current target (but for things to work right when switching
8681 targets, all signals should be in the signal tables). */
8682
8683 static void
8684 info_signals_command (char *signum_exp, int from_tty)
8685 {
8686 enum gdb_signal oursig;
8687
8688 sig_print_header ();
8689
8690 if (signum_exp)
8691 {
8692 /* First see if this is a symbol name. */
8693 oursig = gdb_signal_from_name (signum_exp);
8694 if (oursig == GDB_SIGNAL_UNKNOWN)
8695 {
8696 /* No, try numeric. */
8697 oursig =
8698 gdb_signal_from_command (parse_and_eval_long (signum_exp));
8699 }
8700 sig_print_info (oursig);
8701 return;
8702 }
8703
8704 printf_filtered ("\n");
8705 /* These ugly casts brought to you by the native VAX compiler. */
8706 for (oursig = GDB_SIGNAL_FIRST;
8707 (int) oursig < (int) GDB_SIGNAL_LAST;
8708 oursig = (enum gdb_signal) ((int) oursig + 1))
8709 {
8710 QUIT;
8711
8712 if (oursig != GDB_SIGNAL_UNKNOWN
8713 && oursig != GDB_SIGNAL_DEFAULT && oursig != GDB_SIGNAL_0)
8714 sig_print_info (oursig);
8715 }
8716
8717 printf_filtered (_("\nUse the \"handle\" command "
8718 "to change these tables.\n"));
8719 }
8720
8721 /* The $_siginfo convenience variable is a bit special. We don't know
8722 for sure the type of the value until we actually have a chance to
8723 fetch the data. The type can change depending on gdbarch, so it is
8724 also dependent on which thread you have selected.
8725
8726 1. making $_siginfo be an internalvar that creates a new value on
8727 access.
8728
8729 2. making the value of $_siginfo be an lval_computed value. */
8730
8731 /* This function implements the lval_computed support for reading a
8732 $_siginfo value. */
8733
8734 static void
8735 siginfo_value_read (struct value *v)
8736 {
8737 LONGEST transferred;
8738
8739 /* If we can access registers, so can we access $_siginfo. Likewise
8740 vice versa. */
8741 validate_registers_access ();
8742
8743 transferred =
8744 target_read (&current_target, TARGET_OBJECT_SIGNAL_INFO,
8745 NULL,
8746 value_contents_all_raw (v),
8747 value_offset (v),
8748 TYPE_LENGTH (value_type (v)));
8749
8750 if (transferred != TYPE_LENGTH (value_type (v)))
8751 error (_("Unable to read siginfo"));
8752 }
8753
8754 /* This function implements the lval_computed support for writing a
8755 $_siginfo value. */
8756
8757 static void
8758 siginfo_value_write (struct value *v, struct value *fromval)
8759 {
8760 LONGEST transferred;
8761
8762 /* If we can access registers, so can we access $_siginfo. Likewise
8763 vice versa. */
8764 validate_registers_access ();
8765
8766 transferred = target_write (&current_target,
8767 TARGET_OBJECT_SIGNAL_INFO,
8768 NULL,
8769 value_contents_all_raw (fromval),
8770 value_offset (v),
8771 TYPE_LENGTH (value_type (fromval)));
8772
8773 if (transferred != TYPE_LENGTH (value_type (fromval)))
8774 error (_("Unable to write siginfo"));
8775 }
8776
8777 static const struct lval_funcs siginfo_value_funcs =
8778 {
8779 siginfo_value_read,
8780 siginfo_value_write
8781 };
8782
8783 /* Return a new value with the correct type for the siginfo object of
8784 the current thread using architecture GDBARCH. Return a void value
8785 if there's no object available. */
8786
8787 static struct value *
8788 siginfo_make_value (struct gdbarch *gdbarch, struct internalvar *var,
8789 void *ignore)
8790 {
8791 if (target_has_stack
8792 && !ptid_equal (inferior_ptid, null_ptid)
8793 && gdbarch_get_siginfo_type_p (gdbarch))
8794 {
8795 struct type *type = gdbarch_get_siginfo_type (gdbarch);
8796
8797 return allocate_computed_value (type, &siginfo_value_funcs, NULL);
8798 }
8799
8800 return allocate_value (builtin_type (gdbarch)->builtin_void);
8801 }
8802
8803 \f
8804 /* infcall_suspend_state contains state about the program itself like its
8805 registers and any signal it received when it last stopped.
8806 This state must be restored regardless of how the inferior function call
8807 ends (either successfully, or after it hits a breakpoint or signal)
8808 if the program is to properly continue where it left off. */
8809
8810 struct infcall_suspend_state
8811 {
8812 struct thread_suspend_state thread_suspend;
8813
8814 /* Other fields: */
8815 CORE_ADDR stop_pc;
8816 struct regcache *registers;
8817
8818 /* Format of SIGINFO_DATA or NULL if it is not present. */
8819 struct gdbarch *siginfo_gdbarch;
8820
8821 /* The inferior format depends on SIGINFO_GDBARCH and it has a length of
8822 TYPE_LENGTH (gdbarch_get_siginfo_type ()). For different gdbarch the
8823 content would be invalid. */
8824 gdb_byte *siginfo_data;
8825 };
8826
8827 struct infcall_suspend_state *
8828 save_infcall_suspend_state (void)
8829 {
8830 struct infcall_suspend_state *inf_state;
8831 struct thread_info *tp = inferior_thread ();
8832 struct regcache *regcache = get_current_regcache ();
8833 struct gdbarch *gdbarch = regcache->arch ();
8834 gdb_byte *siginfo_data = NULL;
8835
8836 if (gdbarch_get_siginfo_type_p (gdbarch))
8837 {
8838 struct type *type = gdbarch_get_siginfo_type (gdbarch);
8839 size_t len = TYPE_LENGTH (type);
8840 struct cleanup *back_to;
8841
8842 siginfo_data = (gdb_byte *) xmalloc (len);
8843 back_to = make_cleanup (xfree, siginfo_data);
8844
8845 if (target_read (&current_target, TARGET_OBJECT_SIGNAL_INFO, NULL,
8846 siginfo_data, 0, len) == len)
8847 discard_cleanups (back_to);
8848 else
8849 {
8850 /* Errors ignored. */
8851 do_cleanups (back_to);
8852 siginfo_data = NULL;
8853 }
8854 }
8855
8856 inf_state = XCNEW (struct infcall_suspend_state);
8857
8858 if (siginfo_data)
8859 {
8860 inf_state->siginfo_gdbarch = gdbarch;
8861 inf_state->siginfo_data = siginfo_data;
8862 }
8863
8864 inf_state->thread_suspend = tp->suspend;
8865
8866 /* run_inferior_call will not use the signal due to its `proceed' call with
8867 GDB_SIGNAL_0 anyway. */
8868 tp->suspend.stop_signal = GDB_SIGNAL_0;
8869
8870 inf_state->stop_pc = stop_pc;
8871
8872 inf_state->registers = regcache_dup (regcache);
8873
8874 return inf_state;
8875 }
8876
8877 /* Restore inferior session state to INF_STATE. */
8878
8879 void
8880 restore_infcall_suspend_state (struct infcall_suspend_state *inf_state)
8881 {
8882 struct thread_info *tp = inferior_thread ();
8883 struct regcache *regcache = get_current_regcache ();
8884 struct gdbarch *gdbarch = regcache->arch ();
8885
8886 tp->suspend = inf_state->thread_suspend;
8887
8888 stop_pc = inf_state->stop_pc;
8889
8890 if (inf_state->siginfo_gdbarch == gdbarch)
8891 {
8892 struct type *type = gdbarch_get_siginfo_type (gdbarch);
8893
8894 /* Errors ignored. */
8895 target_write (&current_target, TARGET_OBJECT_SIGNAL_INFO, NULL,
8896 inf_state->siginfo_data, 0, TYPE_LENGTH (type));
8897 }
8898
8899 /* The inferior can be gone if the user types "print exit(0)"
8900 (and perhaps other times). */
8901 if (target_has_execution)
8902 /* NB: The register write goes through to the target. */
8903 regcache_cpy (regcache, inf_state->registers);
8904
8905 discard_infcall_suspend_state (inf_state);
8906 }
8907
8908 static void
8909 do_restore_infcall_suspend_state_cleanup (void *state)
8910 {
8911 restore_infcall_suspend_state ((struct infcall_suspend_state *) state);
8912 }
8913
8914 struct cleanup *
8915 make_cleanup_restore_infcall_suspend_state
8916 (struct infcall_suspend_state *inf_state)
8917 {
8918 return make_cleanup (do_restore_infcall_suspend_state_cleanup, inf_state);
8919 }
8920
8921 void
8922 discard_infcall_suspend_state (struct infcall_suspend_state *inf_state)
8923 {
8924 delete inf_state->registers;
8925 xfree (inf_state->siginfo_data);
8926 xfree (inf_state);
8927 }
8928
8929 struct regcache *
8930 get_infcall_suspend_state_regcache (struct infcall_suspend_state *inf_state)
8931 {
8932 return inf_state->registers;
8933 }
8934
8935 /* infcall_control_state contains state regarding gdb's control of the
8936 inferior itself like stepping control. It also contains session state like
8937 the user's currently selected frame. */
8938
8939 struct infcall_control_state
8940 {
8941 struct thread_control_state thread_control;
8942 struct inferior_control_state inferior_control;
8943
8944 /* Other fields: */
8945 enum stop_stack_kind stop_stack_dummy;
8946 int stopped_by_random_signal;
8947
8948 /* ID if the selected frame when the inferior function call was made. */
8949 struct frame_id selected_frame_id;
8950 };
8951
8952 /* Save all of the information associated with the inferior<==>gdb
8953 connection. */
8954
8955 struct infcall_control_state *
8956 save_infcall_control_state (void)
8957 {
8958 struct infcall_control_state *inf_status =
8959 XNEW (struct infcall_control_state);
8960 struct thread_info *tp = inferior_thread ();
8961 struct inferior *inf = current_inferior ();
8962
8963 inf_status->thread_control = tp->control;
8964 inf_status->inferior_control = inf->control;
8965
8966 tp->control.step_resume_breakpoint = NULL;
8967 tp->control.exception_resume_breakpoint = NULL;
8968
8969 /* Save original bpstat chain to INF_STATUS; replace it in TP with copy of
8970 chain. If caller's caller is walking the chain, they'll be happier if we
8971 hand them back the original chain when restore_infcall_control_state is
8972 called. */
8973 tp->control.stop_bpstat = bpstat_copy (tp->control.stop_bpstat);
8974
8975 /* Other fields: */
8976 inf_status->stop_stack_dummy = stop_stack_dummy;
8977 inf_status->stopped_by_random_signal = stopped_by_random_signal;
8978
8979 inf_status->selected_frame_id = get_frame_id (get_selected_frame (NULL));
8980
8981 return inf_status;
8982 }
8983
8984 static void
8985 restore_selected_frame (const frame_id &fid)
8986 {
8987 frame_info *frame = frame_find_by_id (fid);
8988
8989 /* If inf_status->selected_frame_id is NULL, there was no previously
8990 selected frame. */
8991 if (frame == NULL)
8992 {
8993 warning (_("Unable to restore previously selected frame."));
8994 return;
8995 }
8996
8997 select_frame (frame);
8998 }
8999
9000 /* Restore inferior session state to INF_STATUS. */
9001
9002 void
9003 restore_infcall_control_state (struct infcall_control_state *inf_status)
9004 {
9005 struct thread_info *tp = inferior_thread ();
9006 struct inferior *inf = current_inferior ();
9007
9008 if (tp->control.step_resume_breakpoint)
9009 tp->control.step_resume_breakpoint->disposition = disp_del_at_next_stop;
9010
9011 if (tp->control.exception_resume_breakpoint)
9012 tp->control.exception_resume_breakpoint->disposition
9013 = disp_del_at_next_stop;
9014
9015 /* Handle the bpstat_copy of the chain. */
9016 bpstat_clear (&tp->control.stop_bpstat);
9017
9018 tp->control = inf_status->thread_control;
9019 inf->control = inf_status->inferior_control;
9020
9021 /* Other fields: */
9022 stop_stack_dummy = inf_status->stop_stack_dummy;
9023 stopped_by_random_signal = inf_status->stopped_by_random_signal;
9024
9025 if (target_has_stack)
9026 {
9027 /* The point of the try/catch is that if the stack is clobbered,
9028 walking the stack might encounter a garbage pointer and
9029 error() trying to dereference it. */
9030 TRY
9031 {
9032 restore_selected_frame (inf_status->selected_frame_id);
9033 }
9034 CATCH (ex, RETURN_MASK_ERROR)
9035 {
9036 exception_fprintf (gdb_stderr, ex,
9037 "Unable to restore previously selected frame:\n");
9038 /* Error in restoring the selected frame. Select the
9039 innermost frame. */
9040 select_frame (get_current_frame ());
9041 }
9042 END_CATCH
9043 }
9044
9045 xfree (inf_status);
9046 }
9047
9048 static void
9049 do_restore_infcall_control_state_cleanup (void *sts)
9050 {
9051 restore_infcall_control_state ((struct infcall_control_state *) sts);
9052 }
9053
9054 struct cleanup *
9055 make_cleanup_restore_infcall_control_state
9056 (struct infcall_control_state *inf_status)
9057 {
9058 return make_cleanup (do_restore_infcall_control_state_cleanup, inf_status);
9059 }
9060
9061 void
9062 discard_infcall_control_state (struct infcall_control_state *inf_status)
9063 {
9064 if (inf_status->thread_control.step_resume_breakpoint)
9065 inf_status->thread_control.step_resume_breakpoint->disposition
9066 = disp_del_at_next_stop;
9067
9068 if (inf_status->thread_control.exception_resume_breakpoint)
9069 inf_status->thread_control.exception_resume_breakpoint->disposition
9070 = disp_del_at_next_stop;
9071
9072 /* See save_infcall_control_state for info on stop_bpstat. */
9073 bpstat_clear (&inf_status->thread_control.stop_bpstat);
9074
9075 xfree (inf_status);
9076 }
9077 \f
9078 /* See infrun.h. */
9079
9080 void
9081 clear_exit_convenience_vars (void)
9082 {
9083 clear_internalvar (lookup_internalvar ("_exitsignal"));
9084 clear_internalvar (lookup_internalvar ("_exitcode"));
9085 }
9086 \f
9087
9088 /* User interface for reverse debugging:
9089 Set exec-direction / show exec-direction commands
9090 (returns error unless target implements to_set_exec_direction method). */
9091
9092 enum exec_direction_kind execution_direction = EXEC_FORWARD;
9093 static const char exec_forward[] = "forward";
9094 static const char exec_reverse[] = "reverse";
9095 static const char *exec_direction = exec_forward;
9096 static const char *const exec_direction_names[] = {
9097 exec_forward,
9098 exec_reverse,
9099 NULL
9100 };
9101
9102 static void
9103 set_exec_direction_func (char *args, int from_tty,
9104 struct cmd_list_element *cmd)
9105 {
9106 if (target_can_execute_reverse)
9107 {
9108 if (!strcmp (exec_direction, exec_forward))
9109 execution_direction = EXEC_FORWARD;
9110 else if (!strcmp (exec_direction, exec_reverse))
9111 execution_direction = EXEC_REVERSE;
9112 }
9113 else
9114 {
9115 exec_direction = exec_forward;
9116 error (_("Target does not support this operation."));
9117 }
9118 }
9119
9120 static void
9121 show_exec_direction_func (struct ui_file *out, int from_tty,
9122 struct cmd_list_element *cmd, const char *value)
9123 {
9124 switch (execution_direction) {
9125 case EXEC_FORWARD:
9126 fprintf_filtered (out, _("Forward.\n"));
9127 break;
9128 case EXEC_REVERSE:
9129 fprintf_filtered (out, _("Reverse.\n"));
9130 break;
9131 default:
9132 internal_error (__FILE__, __LINE__,
9133 _("bogus execution_direction value: %d"),
9134 (int) execution_direction);
9135 }
9136 }
9137
9138 static void
9139 show_schedule_multiple (struct ui_file *file, int from_tty,
9140 struct cmd_list_element *c, const char *value)
9141 {
9142 fprintf_filtered (file, _("Resuming the execution of threads "
9143 "of all processes is %s.\n"), value);
9144 }
9145
9146 /* Implementation of `siginfo' variable. */
9147
9148 static const struct internalvar_funcs siginfo_funcs =
9149 {
9150 siginfo_make_value,
9151 NULL,
9152 NULL
9153 };
9154
9155 /* Callback for infrun's target events source. This is marked when a
9156 thread has a pending status to process. */
9157
9158 static void
9159 infrun_async_inferior_event_handler (gdb_client_data data)
9160 {
9161 inferior_event_handler (INF_REG_EVENT, NULL);
9162 }
9163
9164 void
9165 _initialize_infrun (void)
9166 {
9167 int i;
9168 int numsigs;
9169 struct cmd_list_element *c;
9170
9171 /* Register extra event sources in the event loop. */
9172 infrun_async_inferior_event_token
9173 = create_async_event_handler (infrun_async_inferior_event_handler, NULL);
9174
9175 add_info ("signals", info_signals_command, _("\
9176 What debugger does when program gets various signals.\n\
9177 Specify a signal as argument to print info on that signal only."));
9178 add_info_alias ("handle", "signals", 0);
9179
9180 c = add_com ("handle", class_run, handle_command, _("\
9181 Specify how to handle signals.\n\
9182 Usage: handle SIGNAL [ACTIONS]\n\
9183 Args are signals and actions to apply to those signals.\n\
9184 If no actions are specified, the current settings for the specified signals\n\
9185 will be displayed instead.\n\
9186 \n\
9187 Symbolic signals (e.g. SIGSEGV) are recommended but numeric signals\n\
9188 from 1-15 are allowed for compatibility with old versions of GDB.\n\
9189 Numeric ranges may be specified with the form LOW-HIGH (e.g. 1-5).\n\
9190 The special arg \"all\" is recognized to mean all signals except those\n\
9191 used by the debugger, typically SIGTRAP and SIGINT.\n\
9192 \n\
9193 Recognized actions include \"stop\", \"nostop\", \"print\", \"noprint\",\n\
9194 \"pass\", \"nopass\", \"ignore\", or \"noignore\".\n\
9195 Stop means reenter debugger if this signal happens (implies print).\n\
9196 Print means print a message if this signal happens.\n\
9197 Pass means let program see this signal; otherwise program doesn't know.\n\
9198 Ignore is a synonym for nopass and noignore is a synonym for pass.\n\
9199 Pass and Stop may be combined.\n\
9200 \n\
9201 Multiple signals may be specified. Signal numbers and signal names\n\
9202 may be interspersed with actions, with the actions being performed for\n\
9203 all signals cumulatively specified."));
9204 set_cmd_completer (c, handle_completer);
9205
9206 if (!dbx_commands)
9207 stop_command = add_cmd ("stop", class_obscure,
9208 not_just_help_class_command, _("\
9209 There is no `stop' command, but you can set a hook on `stop'.\n\
9210 This allows you to set a list of commands to be run each time execution\n\
9211 of the program stops."), &cmdlist);
9212
9213 add_setshow_zuinteger_cmd ("infrun", class_maintenance, &debug_infrun, _("\
9214 Set inferior debugging."), _("\
9215 Show inferior debugging."), _("\
9216 When non-zero, inferior specific debugging is enabled."),
9217 NULL,
9218 show_debug_infrun,
9219 &setdebuglist, &showdebuglist);
9220
9221 add_setshow_boolean_cmd ("displaced", class_maintenance,
9222 &debug_displaced, _("\
9223 Set displaced stepping debugging."), _("\
9224 Show displaced stepping debugging."), _("\
9225 When non-zero, displaced stepping specific debugging is enabled."),
9226 NULL,
9227 show_debug_displaced,
9228 &setdebuglist, &showdebuglist);
9229
9230 add_setshow_boolean_cmd ("non-stop", no_class,
9231 &non_stop_1, _("\
9232 Set whether gdb controls the inferior in non-stop mode."), _("\
9233 Show whether gdb controls the inferior in non-stop mode."), _("\
9234 When debugging a multi-threaded program and this setting is\n\
9235 off (the default, also called all-stop mode), when one thread stops\n\
9236 (for a breakpoint, watchpoint, exception, or similar events), GDB stops\n\
9237 all other threads in the program while you interact with the thread of\n\
9238 interest. When you continue or step a thread, you can allow the other\n\
9239 threads to run, or have them remain stopped, but while you inspect any\n\
9240 thread's state, all threads stop.\n\
9241 \n\
9242 In non-stop mode, when one thread stops, other threads can continue\n\
9243 to run freely. You'll be able to step each thread independently,\n\
9244 leave it stopped or free to run as needed."),
9245 set_non_stop,
9246 show_non_stop,
9247 &setlist,
9248 &showlist);
9249
9250 numsigs = (int) GDB_SIGNAL_LAST;
9251 signal_stop = XNEWVEC (unsigned char, numsigs);
9252 signal_print = XNEWVEC (unsigned char, numsigs);
9253 signal_program = XNEWVEC (unsigned char, numsigs);
9254 signal_catch = XNEWVEC (unsigned char, numsigs);
9255 signal_pass = XNEWVEC (unsigned char, numsigs);
9256 for (i = 0; i < numsigs; i++)
9257 {
9258 signal_stop[i] = 1;
9259 signal_print[i] = 1;
9260 signal_program[i] = 1;
9261 signal_catch[i] = 0;
9262 }
9263
9264 /* Signals caused by debugger's own actions should not be given to
9265 the program afterwards.
9266
9267 Do not deliver GDB_SIGNAL_TRAP by default, except when the user
9268 explicitly specifies that it should be delivered to the target
9269 program. Typically, that would occur when a user is debugging a
9270 target monitor on a simulator: the target monitor sets a
9271 breakpoint; the simulator encounters this breakpoint and halts
9272 the simulation handing control to GDB; GDB, noting that the stop
9273 address doesn't map to any known breakpoint, returns control back
9274 to the simulator; the simulator then delivers the hardware
9275 equivalent of a GDB_SIGNAL_TRAP to the program being
9276 debugged. */
9277 signal_program[GDB_SIGNAL_TRAP] = 0;
9278 signal_program[GDB_SIGNAL_INT] = 0;
9279
9280 /* Signals that are not errors should not normally enter the debugger. */
9281 signal_stop[GDB_SIGNAL_ALRM] = 0;
9282 signal_print[GDB_SIGNAL_ALRM] = 0;
9283 signal_stop[GDB_SIGNAL_VTALRM] = 0;
9284 signal_print[GDB_SIGNAL_VTALRM] = 0;
9285 signal_stop[GDB_SIGNAL_PROF] = 0;
9286 signal_print[GDB_SIGNAL_PROF] = 0;
9287 signal_stop[GDB_SIGNAL_CHLD] = 0;
9288 signal_print[GDB_SIGNAL_CHLD] = 0;
9289 signal_stop[GDB_SIGNAL_IO] = 0;
9290 signal_print[GDB_SIGNAL_IO] = 0;
9291 signal_stop[GDB_SIGNAL_POLL] = 0;
9292 signal_print[GDB_SIGNAL_POLL] = 0;
9293 signal_stop[GDB_SIGNAL_URG] = 0;
9294 signal_print[GDB_SIGNAL_URG] = 0;
9295 signal_stop[GDB_SIGNAL_WINCH] = 0;
9296 signal_print[GDB_SIGNAL_WINCH] = 0;
9297 signal_stop[GDB_SIGNAL_PRIO] = 0;
9298 signal_print[GDB_SIGNAL_PRIO] = 0;
9299
9300 /* These signals are used internally by user-level thread
9301 implementations. (See signal(5) on Solaris.) Like the above
9302 signals, a healthy program receives and handles them as part of
9303 its normal operation. */
9304 signal_stop[GDB_SIGNAL_LWP] = 0;
9305 signal_print[GDB_SIGNAL_LWP] = 0;
9306 signal_stop[GDB_SIGNAL_WAITING] = 0;
9307 signal_print[GDB_SIGNAL_WAITING] = 0;
9308 signal_stop[GDB_SIGNAL_CANCEL] = 0;
9309 signal_print[GDB_SIGNAL_CANCEL] = 0;
9310 signal_stop[GDB_SIGNAL_LIBRT] = 0;
9311 signal_print[GDB_SIGNAL_LIBRT] = 0;
9312
9313 /* Update cached state. */
9314 signal_cache_update (-1);
9315
9316 add_setshow_zinteger_cmd ("stop-on-solib-events", class_support,
9317 &stop_on_solib_events, _("\
9318 Set stopping for shared library events."), _("\
9319 Show stopping for shared library events."), _("\
9320 If nonzero, gdb will give control to the user when the dynamic linker\n\
9321 notifies gdb of shared library events. The most common event of interest\n\
9322 to the user would be loading/unloading of a new library."),
9323 set_stop_on_solib_events,
9324 show_stop_on_solib_events,
9325 &setlist, &showlist);
9326
9327 add_setshow_enum_cmd ("follow-fork-mode", class_run,
9328 follow_fork_mode_kind_names,
9329 &follow_fork_mode_string, _("\
9330 Set debugger response to a program call of fork or vfork."), _("\
9331 Show debugger response to a program call of fork or vfork."), _("\
9332 A fork or vfork creates a new process. follow-fork-mode can be:\n\
9333 parent - the original process is debugged after a fork\n\
9334 child - the new process is debugged after a fork\n\
9335 The unfollowed process will continue to run.\n\
9336 By default, the debugger will follow the parent process."),
9337 NULL,
9338 show_follow_fork_mode_string,
9339 &setlist, &showlist);
9340
9341 add_setshow_enum_cmd ("follow-exec-mode", class_run,
9342 follow_exec_mode_names,
9343 &follow_exec_mode_string, _("\
9344 Set debugger response to a program call of exec."), _("\
9345 Show debugger response to a program call of exec."), _("\
9346 An exec call replaces the program image of a process.\n\
9347 \n\
9348 follow-exec-mode can be:\n\
9349 \n\
9350 new - the debugger creates a new inferior and rebinds the process\n\
9351 to this new inferior. The program the process was running before\n\
9352 the exec call can be restarted afterwards by restarting the original\n\
9353 inferior.\n\
9354 \n\
9355 same - the debugger keeps the process bound to the same inferior.\n\
9356 The new executable image replaces the previous executable loaded in\n\
9357 the inferior. Restarting the inferior after the exec call restarts\n\
9358 the executable the process was running after the exec call.\n\
9359 \n\
9360 By default, the debugger will use the same inferior."),
9361 NULL,
9362 show_follow_exec_mode_string,
9363 &setlist, &showlist);
9364
9365 add_setshow_enum_cmd ("scheduler-locking", class_run,
9366 scheduler_enums, &scheduler_mode, _("\
9367 Set mode for locking scheduler during execution."), _("\
9368 Show mode for locking scheduler during execution."), _("\
9369 off == no locking (threads may preempt at any time)\n\
9370 on == full locking (no thread except the current thread may run)\n\
9371 This applies to both normal execution and replay mode.\n\
9372 step == scheduler locked during stepping commands (step, next, stepi, nexti).\n\
9373 In this mode, other threads may run during other commands.\n\
9374 This applies to both normal execution and replay mode.\n\
9375 replay == scheduler locked in replay mode and unlocked during normal execution."),
9376 set_schedlock_func, /* traps on target vector */
9377 show_scheduler_mode,
9378 &setlist, &showlist);
9379
9380 add_setshow_boolean_cmd ("schedule-multiple", class_run, &sched_multi, _("\
9381 Set mode for resuming threads of all processes."), _("\
9382 Show mode for resuming threads of all processes."), _("\
9383 When on, execution commands (such as 'continue' or 'next') resume all\n\
9384 threads of all processes. When off (which is the default), execution\n\
9385 commands only resume the threads of the current process. The set of\n\
9386 threads that are resumed is further refined by the scheduler-locking\n\
9387 mode (see help set scheduler-locking)."),
9388 NULL,
9389 show_schedule_multiple,
9390 &setlist, &showlist);
9391
9392 add_setshow_boolean_cmd ("step-mode", class_run, &step_stop_if_no_debug, _("\
9393 Set mode of the step operation."), _("\
9394 Show mode of the step operation."), _("\
9395 When set, doing a step over a function without debug line information\n\
9396 will stop at the first instruction of that function. Otherwise, the\n\
9397 function is skipped and the step command stops at a different source line."),
9398 NULL,
9399 show_step_stop_if_no_debug,
9400 &setlist, &showlist);
9401
9402 add_setshow_auto_boolean_cmd ("displaced-stepping", class_run,
9403 &can_use_displaced_stepping, _("\
9404 Set debugger's willingness to use displaced stepping."), _("\
9405 Show debugger's willingness to use displaced stepping."), _("\
9406 If on, gdb will use displaced stepping to step over breakpoints if it is\n\
9407 supported by the target architecture. If off, gdb will not use displaced\n\
9408 stepping to step over breakpoints, even if such is supported by the target\n\
9409 architecture. If auto (which is the default), gdb will use displaced stepping\n\
9410 if the target architecture supports it and non-stop mode is active, but will not\n\
9411 use it in all-stop mode (see help set non-stop)."),
9412 NULL,
9413 show_can_use_displaced_stepping,
9414 &setlist, &showlist);
9415
9416 add_setshow_enum_cmd ("exec-direction", class_run, exec_direction_names,
9417 &exec_direction, _("Set direction of execution.\n\
9418 Options are 'forward' or 'reverse'."),
9419 _("Show direction of execution (forward/reverse)."),
9420 _("Tells gdb whether to execute forward or backward."),
9421 set_exec_direction_func, show_exec_direction_func,
9422 &setlist, &showlist);
9423
9424 /* Set/show detach-on-fork: user-settable mode. */
9425
9426 add_setshow_boolean_cmd ("detach-on-fork", class_run, &detach_fork, _("\
9427 Set whether gdb will detach the child of a fork."), _("\
9428 Show whether gdb will detach the child of a fork."), _("\
9429 Tells gdb whether to detach the child of a fork."),
9430 NULL, NULL, &setlist, &showlist);
9431
9432 /* Set/show disable address space randomization mode. */
9433
9434 add_setshow_boolean_cmd ("disable-randomization", class_support,
9435 &disable_randomization, _("\
9436 Set disabling of debuggee's virtual address space randomization."), _("\
9437 Show disabling of debuggee's virtual address space randomization."), _("\
9438 When this mode is on (which is the default), randomization of the virtual\n\
9439 address space is disabled. Standalone programs run with the randomization\n\
9440 enabled by default on some platforms."),
9441 &set_disable_randomization,
9442 &show_disable_randomization,
9443 &setlist, &showlist);
9444
9445 /* ptid initializations */
9446 inferior_ptid = null_ptid;
9447 target_last_wait_ptid = minus_one_ptid;
9448
9449 observer_attach_thread_ptid_changed (infrun_thread_ptid_changed);
9450 observer_attach_thread_stop_requested (infrun_thread_stop_requested);
9451 observer_attach_thread_exit (infrun_thread_thread_exit);
9452 observer_attach_inferior_exit (infrun_inferior_exit);
9453
9454 /* Explicitly create without lookup, since that tries to create a
9455 value with a void typed value, and when we get here, gdbarch
9456 isn't initialized yet. At this point, we're quite sure there
9457 isn't another convenience variable of the same name. */
9458 create_internalvar_type_lazy ("_siginfo", &siginfo_funcs, NULL);
9459
9460 add_setshow_boolean_cmd ("observer", no_class,
9461 &observer_mode_1, _("\
9462 Set whether gdb controls the inferior in observer mode."), _("\
9463 Show whether gdb controls the inferior in observer mode."), _("\
9464 In observer mode, GDB can get data from the inferior, but not\n\
9465 affect its execution. Registers and memory may not be changed,\n\
9466 breakpoints may not be set, and the program cannot be interrupted\n\
9467 or signalled."),
9468 set_observer_mode,
9469 show_observer_mode,
9470 &setlist,
9471 &showlist);
9472 }