1/* Multi-process/thread control defs for GDB, the GNU debugger.
2   Copyright (C) 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1997, 1998, 1999,
3   2000, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4   Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
5
6
7   This file is part of GDB.
8
9   This program is free software; you can redistribute it and/or modify
10   it under the terms of the GNU General Public License as published by
11   the Free Software Foundation; either version 3 of the License, or
12   (at your option) any later version.
13
14   This program is distributed in the hope that it will be useful,
15   but WITHOUT ANY WARRANTY; without even the implied warranty of
16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17   GNU General Public License for more details.
18
19   You should have received a copy of the GNU General Public License
20   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
21
22#ifndef GDBTHREAD_H
23#define GDBTHREAD_H
24
25struct symtab;
26
27#include "breakpoint.h"
28#include "frame.h"
29#include "ui-out.h"
30#include "inferior.h"
31
32/* Inferior thread specific part of `struct infcall_control_state'.
33
34   Inferior process counterpart is `struct inferior_control_state'.  */
35
36struct thread_control_state
37{
38  /* User/external stepping state.  */
39
40  /* Step-resume or longjmp-resume breakpoint.  */
41  struct breakpoint *step_resume_breakpoint;
42
43  /* Exception-resume breakpoint.  */
44  struct breakpoint *exception_resume_breakpoint;
45
46  /* Range to single step within.
47
48     If this is nonzero, respond to a single-step signal by continuing
49     to step if the pc is in this range.
50
51     If step_range_start and step_range_end are both 1, it means to
52     step for a single instruction (FIXME: it might clean up
53     wait_for_inferior in a minor way if this were changed to the
54     address of the instruction and that address plus one.  But maybe
55     not).  */
56  CORE_ADDR step_range_start;	/* Inclusive */
57  CORE_ADDR step_range_end;	/* Exclusive */
58
59  /* Stack frame address as of when stepping command was issued.
60     This is how we know when we step into a subroutine call, and how
61     to set the frame for the breakpoint used to step out.  */
62  struct frame_id step_frame_id;
63
64  /* Similarly, the frame ID of the underlying stack frame (skipping
65     any inlined frames).  */
66  struct frame_id step_stack_frame_id;
67
68  /* Nonzero if we are presently stepping over a breakpoint.
69
70     If we hit a breakpoint or watchpoint, and then continue, we need
71     to single step the current thread with breakpoints disabled, to
72     avoid hitting the same breakpoint or watchpoint again.  And we
73     should step just a single thread and keep other threads stopped,
74     so that other threads don't miss breakpoints while they are
75     removed.
76
77     So, this variable simultaneously means that we need to single
78     step the current thread, keep other threads stopped, and that
79     breakpoints should be removed while we step.
80
81     This variable is set either:
82     - in proceed, when we resume inferior on user's explicit request
83     - in keep_going, if handle_inferior_event decides we need to
84     step over breakpoint.
85
86     The variable is cleared in normal_stop.  The proceed calls
87     wait_for_inferior, which calls handle_inferior_event in a loop,
88     and until wait_for_inferior exits, this variable is changed only
89     by keep_going.  */
90  int trap_expected;
91
92  /* Nonzero if the thread is being proceeded for a "finish" command
93     or a similar situation when stop_registers should be saved.  */
94  int proceed_to_finish;
95
96  /* Nonzero if the thread is being proceeded for an inferior function
97     call.  */
98  int in_infcall;
99
100  enum step_over_calls_kind step_over_calls;
101
102  /* Nonzero if stopped due to a step command.  */
103  int stop_step;
104
105  /* Chain containing status of breakpoint(s) the thread stopped
106     at.  */
107  bpstat stop_bpstat;
108};
109
110/* Inferior thread specific part of `struct infcall_suspend_state'.
111
112   Inferior process counterpart is `struct inferior_suspend_state'.  */
113
114struct thread_suspend_state
115{
116  /* Last signal that the inferior received (why it stopped).  */
117  enum target_signal stop_signal;
118};
119
120struct thread_info
121{
122  struct thread_info *next;
123  ptid_t ptid;			/* "Actual process id";
124				    In fact, this may be overloaded with
125				    kernel thread id, etc.  */
126  int num;			/* Convenient handle (GDB thread id) */
127
128  /* The name of the thread, as specified by the user.  This is NULL
129     if the thread does not have a user-given name.  */
130  char *name;
131
132  /* Non-zero means the thread is executing.  Note: this is different
133     from saying that there is an active target and we are stopped at
134     a breakpoint, for instance.  This is a real indicator whether the
135     thread is off and running.  */
136  /* This field is internal to thread.c.  Never access it directly,
137     use is_executing instead.  */
138  int executing_;
139
140  /* Frontend view of the thread state.  Note that the RUNNING/STOPPED
141     states are different from EXECUTING.  When the thread is stopped
142     internally while handling an internal event, like a software
143     single-step breakpoint, EXECUTING will be false, but running will
144     still be true.  As a possible future extension, this could turn
145     into enum { stopped, exited, stepping, finishing, until(ling),
146     running ... }  */
147  /* This field is internal to thread.c.  Never access it directly,
148     use is_running instead.  */
149  int state_;
150
151  /* If this is > 0, then it means there's code out there that relies
152     on this thread being listed.  Don't delete it from the lists even
153     if we detect it exiting.  */
154  int refcount;
155
156  /* State of GDB control of inferior thread execution.
157     See `struct thread_control_state'.  */
158  struct thread_control_state control;
159
160  /* State of inferior thread to restore after GDB is done with an inferior
161     call.  See `struct thread_suspend_state'.  */
162  struct thread_suspend_state suspend;
163
164  int current_line;
165  struct symtab *current_symtab;
166
167  /* Internal stepping state.  */
168
169  /* Record the pc of the thread the last time it stopped.  This is
170     maintained by proceed and keep_going, and used in
171     adjust_pc_after_break to distinguish a hardware single-step
172     SIGTRAP from a breakpoint SIGTRAP.  */
173  CORE_ADDR prev_pc;
174
175  /* Should we step over breakpoint next time keep_going is called?  */
176  int stepping_over_breakpoint;
177
178  /* Set to TRUE if we should finish single-stepping over a breakpoint
179     after hitting the current step-resume breakpoint.  */
180  int step_after_step_resume_breakpoint;
181
182  /* This is set TRUE when a catchpoint of a shared library event
183     triggers.  Since we don't wish to leave the inferior in the
184     solib hook when we report the event, we step the inferior
185     back to user code before stopping and reporting the event.  */
186  int stepping_through_solib_after_catch;
187
188  /* When stepping_through_solib_after_catch is TRUE, this is a
189     list of the catchpoints that should be reported as triggering
190     when we finally do stop stepping.  */
191  bpstat stepping_through_solib_catchpoints;
192
193  /* Per-thread command support.  */
194
195  /* Pointer to what is left to do for an execution command after the
196     target stops.  Used only in asynchronous mode, by targets that
197     support async execution.  Several execution commands use it.  */
198  struct continuation *continuations;
199
200  /* Similar to the above, but used when a single execution command
201     requires several resume/stop iterations.  Used by the step
202     command.  */
203  struct continuation *intermediate_continuations;
204
205  /* If stepping, nonzero means step count is > 1 so don't print frame
206     next time inferior stops if it stops due to stepping.  */
207  int step_multi;
208
209  /* This is used to remember when a fork or vfork event was caught by
210     a catchpoint, and thus the event is to be followed at the next
211     resume of the thread, and not immediately.  */
212  struct target_waitstatus pending_follow;
213
214  /* True if this thread has been explicitly requested to stop.  */
215  int stop_requested;
216
217  /* The initiating frame of a nexting operation, used for deciding
218     which exceptions to intercept.  */
219  struct frame_id initiating_frame;
220
221  /* Private data used by the target vector implementation.  */
222  struct private_thread_info *private;
223
224  /* Function that is called to free PRIVATE.  If this is NULL, then
225     xfree will be called on PRIVATE.  */
226  void (*private_dtor) (struct private_thread_info *);
227};
228
229/* Create an empty thread list, or empty the existing one.  */
230extern void init_thread_list (void);
231
232/* Add a thread to the thread list, print a message
233   that a new thread is found, and return the pointer to
234   the new thread.  Caller my use this pointer to
235   initialize the private thread data.  */
236extern struct thread_info *add_thread (ptid_t ptid);
237
238/* Same as add_thread, but does not print a message
239   about new thread.  */
240extern struct thread_info *add_thread_silent (ptid_t ptid);
241
242/* Same as add_thread, and sets the private info.  */
243extern struct thread_info *add_thread_with_info (ptid_t ptid,
244						 struct private_thread_info *);
245
246/* Delete an existing thread list entry.  */
247extern void delete_thread (ptid_t);
248
249/* Delete an existing thread list entry, and be quiet about it.  Used
250   after the process this thread having belonged to having already
251   exited, for example.  */
252extern void delete_thread_silent (ptid_t);
253
254/* Delete a step_resume_breakpoint from the thread database.  */
255extern void delete_step_resume_breakpoint (struct thread_info *);
256
257/* Delete an exception_resume_breakpoint from the thread database.  */
258extern void delete_exception_resume_breakpoint (struct thread_info *);
259
260/* Translate the integer thread id (GDB's homegrown id, not the system's)
261   into a "pid" (which may be overloaded with extra thread information).  */
262extern ptid_t thread_id_to_pid (int);
263
264/* Translate a 'pid' (which may be overloaded with extra thread information)
265   into the integer thread id (GDB's homegrown id, not the system's).  */
266extern int pid_to_thread_id (ptid_t ptid);
267
268/* Boolean test for an already-known pid (which may be overloaded with
269   extra thread information).  */
270extern int in_thread_list (ptid_t ptid);
271
272/* Boolean test for an already-known thread id (GDB's homegrown id,
273   not the system's).  */
274extern int valid_thread_id (int thread);
275
276/* Search function to lookup a thread by 'pid'.  */
277extern struct thread_info *find_thread_ptid (ptid_t ptid);
278
279/* Find thread by GDB user-visible thread number.  */
280struct thread_info *find_thread_id (int num);
281
282/* Finds the first thread of the inferior given by PID.  If PID is -1,
283   returns the first thread in the list.  */
284struct thread_info *first_thread_of_process (int pid);
285
286/* Returns any thread of process PID.  */
287extern struct thread_info *any_thread_of_process (int pid);
288
289/* Returns any non-exited thread of process PID, giving preference for
290   not executing threads.  */
291extern struct thread_info *any_live_thread_of_process (int pid);
292
293/* Change the ptid of thread OLD_PTID to NEW_PTID.  */
294void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
295
296/* Iterator function to call a user-provided callback function
297   once for each known thread.  */
298typedef int (*thread_callback_func) (struct thread_info *, void *);
299extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
300
301extern int thread_count (void);
302
303/* Switch from one thread to another.  */
304extern void switch_to_thread (ptid_t ptid);
305
306/* Marks thread PTID is running, or stopped.
307   If PIDGET (PTID) is -1, marks all threads.  */
308extern void set_running (ptid_t ptid, int running);
309
310/* Marks or clears thread(s) PTID as having been requested to stop.
311   If PTID is MINUS_ONE_PTID, applies to all threads.  If
312   ptid_is_pid(PTID) is true, applies to all threads of the process
313   pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
314   observer is called with PTID as argument.  */
315extern void set_stop_requested (ptid_t ptid, int stop);
316
317/* NOTE: Since the thread state is not a boolean, most times, you do
318   not want to check it with negation.  If you really want to check if
319   the thread is stopped,
320
321    use (good):
322
323     if (is_stopped (ptid))
324
325    instead of (bad):
326
327     if (!is_running (ptid))
328
329   The latter also returns true on exited threads, most likelly not
330   what you want.  */
331
332/* Reports if in the frontend's perpective, thread PTID is running.  */
333extern int is_running (ptid_t ptid);
334
335/* Is this thread listed, but known to have exited?  We keep it listed
336   (but not visible) until it's safe to delete.  */
337extern int is_exited (ptid_t ptid);
338
339/* In the frontend's perpective, is this thread stopped?  */
340extern int is_stopped (ptid_t ptid);
341
342/* In the frontend's perpective is there any thread running?  */
343extern int any_running (void);
344
345/* Marks thread PTID as executing, or not.  If PIDGET (PTID) is -1,
346   marks all threads.
347
348   Note that this is different from the running state.  See the
349   description of state_ and executing_ fields of struct
350   thread_info.  */
351extern void set_executing (ptid_t ptid, int executing);
352
353/* Reports if thread PTID is executing.  */
354extern int is_executing (ptid_t ptid);
355
356/* Merge the executing property of thread PTID over to its thread
357   state property (frontend running/stopped view).
358
359   "not executing" -> "stopped"
360   "executing"     -> "running"
361   "exited"        -> "exited"
362
363   If PIDGET (PTID) is -1, go over all threads.
364
365   Notifications are only emitted if the thread state did change.  */
366extern void finish_thread_state (ptid_t ptid);
367
368/* Same as FINISH_THREAD_STATE, but with an interface suitable to be
369   registered as a cleanup.  PTID_P points to the ptid_t that is
370   passed to FINISH_THREAD_STATE.  */
371extern void finish_thread_state_cleanup (void *ptid_p);
372
373/* Commands with a prefix of `thread'.  */
374extern struct cmd_list_element *thread_cmd_list;
375
376/* Print notices on thread events (attach, detach, etc.), set with
377   `set print thread-events'.  */
378extern int print_thread_events;
379
380extern void print_thread_info (struct ui_out *uiout, char *threads,
381			       int pid);
382
383extern struct cleanup *make_cleanup_restore_current_thread (void);
384
385/* Returns a pointer into the thread_info corresponding to
386   INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
387extern struct thread_info* inferior_thread (void);
388
389extern void update_thread_list (void);
390
391#endif /* GDBTHREAD_H */
392