gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2014 Free Software Foundation, Inc.
   3    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   4
   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 #ifndef GDBTHREAD_H
  22 #define GDBTHREAD_H
  23
  24 struct symtab;
  25
  26 #include "breakpoint.h"
  27 #include "frame.h"
  28 #include "ui-out.h"
  29 #include "inferior.h"
  30 #include "btrace.h"
  31
  32 /* Frontend view of the thread state.  Possible extensions: stepping,
  33    finishing, until(ling),...  */
  34 enum thread_state
  35 {
  36   THREAD_STOPPED,
  37   THREAD_RUNNING,
  38   THREAD_EXITED,
  39 };
  40
  41 /* Inferior thread specific part of `struct infcall_control_state'.
  42
  43    Inferior process counterpart is `struct inferior_control_state'.  */
  44
  45 struct thread_control_state
  46 {
  47   /* User/external stepping state.  */
  48
  49   /* Step-resume or longjmp-resume breakpoint.  */
  50   struct breakpoint *step_resume_breakpoint;
  51
  52   /* Exception-resume breakpoint.  */
  53   struct breakpoint *exception_resume_breakpoint;
  54
  55   /* Range to single step within.
  56
  57      If this is nonzero, respond to a single-step signal by continuing
  58      to step if the pc is in this range.
  59
  60      If step_range_start and step_range_end are both 1, it means to
  61      step for a single instruction (FIXME: it might clean up
  62      wait_for_inferior in a minor way if this were changed to the
  63      address of the instruction and that address plus one.  But maybe
  64      not).  */
  65   CORE_ADDR step_range_start;   /* Inclusive */
  66   CORE_ADDR step_range_end;     /* Exclusive */
  67
  68   /* If GDB issues a target step request, and this is nonzero, the
  69      target should single-step this thread once, and then continue
  70      single-stepping it without GDB core involvement as long as the
  71      thread stops in the step range above.  If this is zero, the
  72      target should ignore the step range, and only issue one single
  73      step.  */
  74   int may_range_step;
  75
  76   /* Stack frame address as of when stepping command was issued.
  77      This is how we know when we step into a subroutine call, and how
  78      to set the frame for the breakpoint used to step out.  */
  79   struct frame_id step_frame_id;
  80
  81   /* Similarly, the frame ID of the underlying stack frame (skipping
  82      any inlined frames).  */
  83   struct frame_id step_stack_frame_id;
  84
  85   /* Nonzero if we are presently stepping over a breakpoint.
  86
  87      If we hit a breakpoint or watchpoint, and then continue, we need
  88      to single step the current thread with breakpoints disabled, to
  89      avoid hitting the same breakpoint or watchpoint again.  And we
  90      should step just a single thread and keep other threads stopped,
  91      so that other threads don't miss breakpoints while they are
  92      removed.
  93
  94      So, this variable simultaneously means that we need to single
  95      step the current thread, keep other threads stopped, and that
  96      breakpoints should be removed while we step.
  97
  98      This variable is set either:
  99      - in proceed, when we resume inferior on user's explicit request
 100      - in keep_going, if handle_inferior_event decides we need to
 101      step over breakpoint.
 102
 103      The variable is cleared in normal_stop.  The proceed calls
 104      wait_for_inferior, which calls handle_inferior_event in a loop,
 105      and until wait_for_inferior exits, this variable is changed only
 106      by keep_going.  */
 107   int trap_expected;
 108
 109   /* Nonzero if the thread is being proceeded for a "finish" command
 110      or a similar situation when stop_registers should be saved.  */
 111   int proceed_to_finish;
 112
 113   /* Nonzero if the thread is being proceeded for an inferior function
 114      call.  */
 115   int in_infcall;
 116
 117   enum step_over_calls_kind step_over_calls;
 118
 119   /* Nonzero if stopped due to a step command.  */
 120   int stop_step;
 121
 122   /* Chain containing status of breakpoint(s) the thread stopped
 123      at.  */
 124   bpstat stop_bpstat;
 125
 126   /* The interpreter that issued the execution command.  NULL if the
 127      thread was resumed as a result of a command applied to some other
 128      thread (e.g., "next" with scheduler-locking off).  */
 129   struct interp *command_interp;
 130 };
 131
 132 /* Inferior thread specific part of `struct infcall_suspend_state'.
 133
 134    Inferior process counterpart is `struct inferior_suspend_state'.  */
 135
 136 struct thread_suspend_state
 137 {
 138   /* Last signal that the inferior received (why it stopped).  */
 139   enum gdb_signal stop_signal;
 140 };
 141
 142 struct thread_info
 143 {
 144   struct thread_info *next;
 145   ptid_t ptid;                  /* "Actual process id";
 146                                     In fact, this may be overloaded with
 147                                     kernel thread id, etc.  */
 148   int num;                      /* Convenient handle (GDB thread id) */
 149
 150   /* The name of the thread, as specified by the user.  This is NULL
 151      if the thread does not have a user-given name.  */
 152   char *name;
 153
 154   /* Non-zero means the thread is executing.  Note: this is different
 155      from saying that there is an active target and we are stopped at
 156      a breakpoint, for instance.  This is a real indicator whether the
 157      thread is off and running.  */
 158   int executing;
 159
 160   /* Frontend view of the thread state.  Note that the RUNNING/STOPPED
 161      states are different from EXECUTING.  When the thread is stopped
 162      internally while handling an internal event, like a software
 163      single-step breakpoint, EXECUTING will be false, but running will
 164      still be true.  As a possible future extension, this could turn
 165      into enum { stopped, exited, stepping, finishing, until(ling),
 166      running ... }  */
 167   int state;
 168
 169   /* If this is > 0, then it means there's code out there that relies
 170      on this thread being listed.  Don't delete it from the lists even
 171      if we detect it exiting.  */
 172   int refcount;
 173
 174   /* State of GDB control of inferior thread execution.
 175      See `struct thread_control_state'.  */
 176   struct thread_control_state control;
 177
 178   /* State of inferior thread to restore after GDB is done with an inferior
 179      call.  See `struct thread_suspend_state'.  */
 180   struct thread_suspend_state suspend;
 181
 182   int current_line;
 183   struct symtab *current_symtab;
 184
 185   /* Internal stepping state.  */
 186
 187   /* Record the pc of the thread the last time it stopped.  This is
 188      maintained by proceed and keep_going, and used in
 189      adjust_pc_after_break to distinguish a hardware single-step
 190      SIGTRAP from a breakpoint SIGTRAP.  */
 191   CORE_ADDR prev_pc;
 192
 193   /* Should we step over breakpoint next time keep_going is called?  */
 194   int stepping_over_breakpoint;
 195
 196   /* Set to TRUE if we should finish single-stepping over a breakpoint
 197      after hitting the current step-resume breakpoint.  The context here
 198      is that GDB is to do `next' or `step' while signal arrives.
 199      When stepping over a breakpoint and signal arrives, GDB will attempt
 200      to skip signal handler, so it inserts a step_resume_breakpoint at the
 201      signal return address, and resume inferior.
 202      step_after_step_resume_breakpoint is set to TRUE at this moment in
 203      order to keep GDB in mind that there is still a breakpoint to step over
 204      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 205   int step_after_step_resume_breakpoint;
 206
 207   /* Per-thread command support.  */
 208
 209   /* Pointer to what is left to do for an execution command after the
 210      target stops.  Used only in asynchronous mode, by targets that
 211      support async execution.  Several execution commands use it.  */
 212   struct continuation *continuations;
 213
 214   /* Similar to the above, but used when a single execution command
 215      requires several resume/stop iterations.  Used by the step
 216      command.  */
 217   struct continuation *intermediate_continuations;
 218
 219   /* If stepping, nonzero means step count is > 1 so don't print frame
 220      next time inferior stops if it stops due to stepping.  */
 221   int step_multi;
 222
 223   /* This is used to remember when a fork or vfork event was caught by
 224      a catchpoint, and thus the event is to be followed at the next
 225      resume of the thread, and not immediately.  */
 226   struct target_waitstatus pending_follow;
 227
 228   /* True if this thread has been explicitly requested to stop.  */
 229   int stop_requested;
 230
 231   /* The initiating frame of a nexting operation, used for deciding
 232      which exceptions to intercept.  If it is null_frame_id no
 233      bp_longjmp or bp_exception but longjmp has been caught just for
 234      bp_longjmp_call_dummy.  */
 235   struct frame_id initiating_frame;
 236
 237   /* Private data used by the target vector implementation.  */
 238   struct private_thread_info *private;
 239
 240   /* Function that is called to free PRIVATE.  If this is NULL, then
 241      xfree will be called on PRIVATE.  */
 242   void (*private_dtor) (struct private_thread_info *);
 243
 244   /* Branch trace information for this thread.  */
 245   struct btrace_thread_info btrace;
 246 };
 247
 248 /* Create an empty thread list, or empty the existing one.  */
 249 extern void init_thread_list (void);
 250
 251 /* Add a thread to the thread list, print a message
 252    that a new thread is found, and return the pointer to
 253    the new thread.  Caller my use this pointer to
 254    initialize the private thread data.  */
 255 extern struct thread_info *add_thread (ptid_t ptid);
 256
 257 /* Same as add_thread, but does not print a message
 258    about new thread.  */
 259 extern struct thread_info *add_thread_silent (ptid_t ptid);
 260
 261 /* Same as add_thread, and sets the private info.  */
 262 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 263                                                  struct private_thread_info *);
 264
 265 /* Delete an existing thread list entry.  */
 266 extern void delete_thread (ptid_t);
 267
 268 /* Delete an existing thread list entry, and be quiet about it.  Used
 269    after the process this thread having belonged to having already
 270    exited, for example.  */
 271 extern void delete_thread_silent (ptid_t);
 272
 273 /* Delete a step_resume_breakpoint from the thread database.  */
 274 extern void delete_step_resume_breakpoint (struct thread_info *);
 275
 276 /* Delete an exception_resume_breakpoint from the thread database.  */
 277 extern void delete_exception_resume_breakpoint (struct thread_info *);
 278
 279 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 280    into a "pid" (which may be overloaded with extra thread information).  */
 281 extern ptid_t thread_id_to_pid (int);
 282
 283 /* Translate a 'pid' (which may be overloaded with extra thread information)
 284    into the integer thread id (GDB's homegrown id, not the system's).  */
 285 extern int pid_to_thread_id (ptid_t ptid);
 286
 287 /* Boolean test for an already-known pid (which may be overloaded with
 288    extra thread information).  */
 289 extern int in_thread_list (ptid_t ptid);
 290
 291 /* Boolean test for an already-known thread id (GDB's homegrown id,
 292    not the system's).  */
 293 extern int valid_thread_id (int thread);
 294
 295 /* Search function to lookup a thread by 'pid'.  */
 296 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 297
 298 /* Find thread by GDB user-visible thread number.  */
 299 struct thread_info *find_thread_id (int num);
 300
 301 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 302    returns the first thread in the list.  */
 303 struct thread_info *first_thread_of_process (int pid);
 304
 305 /* Returns any thread of process PID.  */
 306 extern struct thread_info *any_thread_of_process (int pid);
 307
 308 /* Returns any non-exited thread of process PID, giving preference for
 309    not executing threads.  */
 310 extern struct thread_info *any_live_thread_of_process (int pid);
 311
 312 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 313 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 314
 315 /* Iterator function to call a user-provided callback function
 316    once for each known thread.  */
 317 typedef int (*thread_callback_func) (struct thread_info *, void *);
 318 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 319
 320 /* Traverse all threads, except those that have THREAD_EXITED
 321    state.  */
 322
 323 #define ALL_NON_EXITED_THREADS(T)                               \
 324   for (T = thread_list; T; T = T->next) \
 325     if ((T)->state != THREAD_EXITED)
 326
 327 extern int thread_count (void);
 328
 329 /* Switch from one thread to another.  */
 330 extern void switch_to_thread (ptid_t ptid);
 331
 332 /* Marks thread PTID is running, or stopped.
 333    If ptid_get_pid (PTID) is -1, marks all threads.  */
 334 extern void set_running (ptid_t ptid, int running);
 335
 336 /* Marks or clears thread(s) PTID as having been requested to stop.
 337    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 338    ptid_is_pid(PTID) is true, applies to all threads of the process
 339    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 340    observer is called with PTID as argument.  */
 341 extern void set_stop_requested (ptid_t ptid, int stop);
 342
 343 /* NOTE: Since the thread state is not a boolean, most times, you do
 344    not want to check it with negation.  If you really want to check if
 345    the thread is stopped,
 346
 347     use (good):
 348
 349      if (is_stopped (ptid))
 350
 351     instead of (bad):
 352
 353      if (!is_running (ptid))
 354
 355    The latter also returns true on exited threads, most likelly not
 356    what you want.  */
 357
 358 /* Reports if in the frontend's perpective, thread PTID is running.  */
 359 extern int is_running (ptid_t ptid);
 360
 361 /* Is this thread listed, but known to have exited?  We keep it listed
 362    (but not visible) until it's safe to delete.  */
 363 extern int is_exited (ptid_t ptid);
 364
 365 /* In the frontend's perpective, is this thread stopped?  */
 366 extern int is_stopped (ptid_t ptid);
 367
 368 /* In the frontend's perpective is there any thread running?  */
 369 extern int any_running (void);
 370
 371 /* Marks thread PTID as executing, or not.  If ptid_get_pid (PTID) is -1,
 372    marks all threads.
 373
 374    Note that this is different from the running state.  See the
 375    description of state and executing fields of struct
 376    thread_info.  */
 377 extern void set_executing (ptid_t ptid, int executing);
 378
 379 /* Reports if thread PTID is executing.  */
 380 extern int is_executing (ptid_t ptid);
 381
 382 /* Merge the executing property of thread PTID over to its thread
 383    state property (frontend running/stopped view).
 384
 385    "not executing" -> "stopped"
 386    "executing"     -> "running"
 387    "exited"        -> "exited"
 388
 389    If ptid_get_pid (PTID) is -1, go over all threads.
 390
 391    Notifications are only emitted if the thread state did change.  */
 392 extern void finish_thread_state (ptid_t ptid);
 393
 394 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 395    registered as a cleanup.  PTID_P points to the ptid_t that is
 396    passed to FINISH_THREAD_STATE.  */
 397 extern void finish_thread_state_cleanup (void *ptid_p);
 398
 399 /* Commands with a prefix of `thread'.  */
 400 extern struct cmd_list_element *thread_cmd_list;
 401
 402 /* Print notices on thread events (attach, detach, etc.), set with
 403    `set print thread-events'.  */
 404 extern int print_thread_events;
 405
 406 extern void print_thread_info (struct ui_out *uiout, char *threads,
 407                                int pid);
 408
 409 extern struct cleanup *make_cleanup_restore_current_thread (void);
 410
 411 /* Returns a pointer into the thread_info corresponding to
 412    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 413 extern struct thread_info* inferior_thread (void);
 414
 415 extern void update_thread_list (void);
 416
 417 /* Return true if PC is in the stepping range of THREAD.  */
 418
 419 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 420
 421 extern struct thread_info *thread_list;
 422
 423 #endif /* GDBTHREAD_H */