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   /* Breakpoints used for software single stepping.  Plural, because
  56      it may have multiple locations.  E.g., if stepping over a
  57      conditional branch instruction we can't decode the condition for,
  58      we'll need to put a breakpoint at the branch destination, and
  59      another at the instruction after the branch.  */
  60   struct breakpoint *single_step_breakpoints;
  61
  62   /* Range to single step within.
  63
  64      If this is nonzero, respond to a single-step signal by continuing
  65      to step if the pc is in this range.
  66
  67      If step_range_start and step_range_end are both 1, it means to
  68      step for a single instruction (FIXME: it might clean up
  69      wait_for_inferior in a minor way if this were changed to the
  70      address of the instruction and that address plus one.  But maybe
  71      not).  */
  72   CORE_ADDR step_range_start;   /* Inclusive */
  73   CORE_ADDR step_range_end;     /* Exclusive */
  74
  75   /* If GDB issues a target step request, and this is nonzero, the
  76      target should single-step this thread once, and then continue
  77      single-stepping it without GDB core involvement as long as the
  78      thread stops in the step range above.  If this is zero, the
  79      target should ignore the step range, and only issue one single
  80      step.  */
  81   int may_range_step;
  82
  83   /* Stack frame address as of when stepping command was issued.
  84      This is how we know when we step into a subroutine call, and how
  85      to set the frame for the breakpoint used to step out.  */
  86   struct frame_id step_frame_id;
  87
  88   /* Similarly, the frame ID of the underlying stack frame (skipping
  89      any inlined frames).  */
  90   struct frame_id step_stack_frame_id;
  91
  92   /* Nonzero if we are presently stepping over a breakpoint.
  93
  94      If we hit a breakpoint or watchpoint, and then continue, we need
  95      to single step the current thread with breakpoints disabled, to
  96      avoid hitting the same breakpoint or watchpoint again.  And we
  97      should step just a single thread and keep other threads stopped,
  98      so that other threads don't miss breakpoints while they are
  99      removed.
 100
 101      So, this variable simultaneously means that we need to single
 102      step the current thread, keep other threads stopped, and that
 103      breakpoints should be removed while we step.
 104
 105      This variable is set either:
 106      - in proceed, when we resume inferior on user's explicit request
 107      - in keep_going, if handle_inferior_event decides we need to
 108      step over breakpoint.
 109
 110      The variable is cleared in normal_stop.  The proceed calls
 111      wait_for_inferior, which calls handle_inferior_event in a loop,
 112      and until wait_for_inferior exits, this variable is changed only
 113      by keep_going.  */
 114   int trap_expected;
 115
 116   /* Nonzero if the thread is being proceeded for a "finish" command
 117      or a similar situation when stop_registers should be saved.  */
 118   int proceed_to_finish;
 119
 120   /* Nonzero if the thread is being proceeded for an inferior function
 121      call.  */
 122   int in_infcall;
 123
 124   enum step_over_calls_kind step_over_calls;
 125
 126   /* Nonzero if stopped due to a step command.  */
 127   int stop_step;
 128
 129   /* Chain containing status of breakpoint(s) the thread stopped
 130      at.  */
 131   bpstat stop_bpstat;
 132
 133   /* The interpreter that issued the execution command.  NULL if the
 134      thread was resumed as a result of a command applied to some other
 135      thread (e.g., "next" with scheduler-locking off).  */
 136   struct interp *command_interp;
 137 };
 138
 139 /* Inferior thread specific part of `struct infcall_suspend_state'.
 140
 141    Inferior process counterpart is `struct inferior_suspend_state'.  */
 142
 143 struct thread_suspend_state
 144 {
 145   /* Last signal that the inferior received (why it stopped).  When
 146      the thread is resumed, this signal is delivered.  Note: the
 147      target should not check whether the signal is in pass state,
 148      because the signal may have been explicitly passed with the
 149      "signal" command, which overrides "handle nopass".  If the signal
 150      should be suppressed, the core will take care of clearing this
 151      before the target is resumed.  */
 152   enum gdb_signal stop_signal;
 153 };
 154
 155 struct thread_info
 156 {
 157   struct thread_info *next;
 158   ptid_t ptid;                  /* "Actual process id";
 159                                     In fact, this may be overloaded with
 160                                     kernel thread id, etc.  */
 161   int num;                      /* Convenient handle (GDB thread id) */
 162
 163   /* The name of the thread, as specified by the user.  This is NULL
 164      if the thread does not have a user-given name.  */
 165   char *name;
 166
 167   /* Non-zero means the thread is executing.  Note: this is different
 168      from saying that there is an active target and we are stopped at
 169      a breakpoint, for instance.  This is a real indicator whether the
 170      thread is off and running.  */
 171   int executing;
 172
 173   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 174      THREAD_STOPPED states are different from EXECUTING.  When the
 175      thread is stopped internally while handling an internal event,
 176      like a software single-step breakpoint, EXECUTING will be false,
 177      but STATE will still be THREAD_RUNNING.  */
 178   enum thread_state state;
 179
 180   /* If this is > 0, then it means there's code out there that relies
 181      on this thread being listed.  Don't delete it from the lists even
 182      if we detect it exiting.  */
 183   int refcount;
 184
 185   /* State of GDB control of inferior thread execution.
 186      See `struct thread_control_state'.  */
 187   struct thread_control_state control;
 188
 189   /* State of inferior thread to restore after GDB is done with an inferior
 190      call.  See `struct thread_suspend_state'.  */
 191   struct thread_suspend_state suspend;
 192
 193   int current_line;
 194   struct symtab *current_symtab;
 195
 196   /* Internal stepping state.  */
 197
 198   /* Record the pc of the thread the last time it stopped.  This is
 199      maintained by proceed and keep_going, and used in
 200      adjust_pc_after_break to distinguish a hardware single-step
 201      SIGTRAP from a breakpoint SIGTRAP.  */
 202   CORE_ADDR prev_pc;
 203
 204   /* Did we set the thread stepping a breakpoint instruction?  This is
 205      used in conjunction with PREV_PC to decide whether to adjust the
 206      PC.  */
 207   int stepped_breakpoint;
 208
 209   /* Should we step over breakpoint next time keep_going is called?  */
 210   int stepping_over_breakpoint;
 211
 212   /* Should we step over a watchpoint next time keep_going is called?
 213      This is needed on targets with non-continuable, non-steppable
 214      watchpoints.  */
 215   int stepping_over_watchpoint;
 216
 217   /* Set to TRUE if we should finish single-stepping over a breakpoint
 218      after hitting the current step-resume breakpoint.  The context here
 219      is that GDB is to do `next' or `step' while signal arrives.
 220      When stepping over a breakpoint and signal arrives, GDB will attempt
 221      to skip signal handler, so it inserts a step_resume_breakpoint at the
 222      signal return address, and resume inferior.
 223      step_after_step_resume_breakpoint is set to TRUE at this moment in
 224      order to keep GDB in mind that there is still a breakpoint to step over
 225      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 226   int step_after_step_resume_breakpoint;
 227
 228   /* Per-thread command support.  */
 229
 230   /* Pointer to what is left to do for an execution command after the
 231      target stops.  Used only in asynchronous mode, by targets that
 232      support async execution.  Several execution commands use it.  */
 233   struct continuation *continuations;
 234
 235   /* Similar to the above, but used when a single execution command
 236      requires several resume/stop iterations.  Used by the step
 237      command.  */
 238   struct continuation *intermediate_continuations;
 239
 240   /* If stepping, nonzero means step count is > 1 so don't print frame
 241      next time inferior stops if it stops due to stepping.  */
 242   int step_multi;
 243
 244   /* This is used to remember when a fork or vfork event was caught by
 245      a catchpoint, and thus the event is to be followed at the next
 246      resume of the thread, and not immediately.  */
 247   struct target_waitstatus pending_follow;
 248
 249   /* True if this thread has been explicitly requested to stop.  */
 250   int stop_requested;
 251
 252   /* The initiating frame of a nexting operation, used for deciding
 253      which exceptions to intercept.  If it is null_frame_id no
 254      bp_longjmp or bp_exception but longjmp has been caught just for
 255      bp_longjmp_call_dummy.  */
 256   struct frame_id initiating_frame;
 257
 258   /* Private data used by the target vector implementation.  */
 259   struct private_thread_info *private;
 260
 261   /* Function that is called to free PRIVATE.  If this is NULL, then
 262      xfree will be called on PRIVATE.  */
 263   void (*private_dtor) (struct private_thread_info *);
 264
 265   /* Branch trace information for this thread.  */
 266   struct btrace_thread_info btrace;
 267 };
 268
 269 /* Create an empty thread list, or empty the existing one.  */
 270 extern void init_thread_list (void);
 271
 272 /* Add a thread to the thread list, print a message
 273    that a new thread is found, and return the pointer to
 274    the new thread.  Caller my use this pointer to
 275    initialize the private thread data.  */
 276 extern struct thread_info *add_thread (ptid_t ptid);
 277
 278 /* Same as add_thread, but does not print a message
 279    about new thread.  */
 280 extern struct thread_info *add_thread_silent (ptid_t ptid);
 281
 282 /* Same as add_thread, and sets the private info.  */
 283 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 284                                                  struct private_thread_info *);
 285
 286 /* Delete an existing thread list entry.  */
 287 extern void delete_thread (ptid_t);
 288
 289 /* Delete an existing thread list entry, and be quiet about it.  Used
 290    after the process this thread having belonged to having already
 291    exited, for example.  */
 292 extern void delete_thread_silent (ptid_t);
 293
 294 /* Delete a step_resume_breakpoint from the thread database.  */
 295 extern void delete_step_resume_breakpoint (struct thread_info *);
 296
 297 /* Delete an exception_resume_breakpoint from the thread database.  */
 298 extern void delete_exception_resume_breakpoint (struct thread_info *);
 299
 300 /* Delete the single-step breakpoints of thread TP, if any.  */
 301 extern void delete_single_step_breakpoints (struct thread_info *tp);
 302
 303 /* Check if the thread has software single stepping breakpoints
 304    set.  */
 305 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 306
 307 /* Check whether the thread has software single stepping breakpoints
 308    set at PC.  */
 309 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 310                                                    struct address_space *aspace,
 311                                                    CORE_ADDR addr);
 312
 313 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 314    into a "pid" (which may be overloaded with extra thread information).  */
 315 extern ptid_t thread_id_to_pid (int);
 316
 317 /* Translate a 'pid' (which may be overloaded with extra thread information)
 318    into the integer thread id (GDB's homegrown id, not the system's).  */
 319 extern int pid_to_thread_id (ptid_t ptid);
 320
 321 /* Boolean test for an already-known pid (which may be overloaded with
 322    extra thread information).  */
 323 extern int in_thread_list (ptid_t ptid);
 324
 325 /* Boolean test for an already-known thread id (GDB's homegrown id,
 326    not the system's).  */
 327 extern int valid_thread_id (int thread);
 328
 329 /* Search function to lookup a thread by 'pid'.  */
 330 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 331
 332 /* Find thread by GDB user-visible thread number.  */
 333 struct thread_info *find_thread_id (int num);
 334
 335 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 336    returns the first thread in the list.  */
 337 struct thread_info *first_thread_of_process (int pid);
 338
 339 /* Returns any thread of process PID, giving preference to the current
 340    thread.  */
 341 extern struct thread_info *any_thread_of_process (int pid);
 342
 343 /* Returns any non-exited thread of process PID, giving preference to
 344    the current thread, and to not executing threads.  */
 345 extern struct thread_info *any_live_thread_of_process (int pid);
 346
 347 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 348 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 349
 350 /* Iterator function to call a user-provided callback function
 351    once for each known thread.  */
 352 typedef int (*thread_callback_func) (struct thread_info *, void *);
 353 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 354
 355 /* Traverse all threads, except those that have THREAD_EXITED
 356    state.  */
 357
 358 #define ALL_NON_EXITED_THREADS(T)                               \
 359   for (T = thread_list; T; T = T->next) \
 360     if ((T)->state != THREAD_EXITED)
 361
 362 /* Like ALL_NON_EXITED_THREADS, but allows deleting the currently
 363    iterated thread.  */
 364 #define ALL_NON_EXITED_THREADS_SAFE(T, TMP)     \
 365   for ((T) = thread_list;                       \
 366        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 367        (T) = (TMP))                             \
 368     if ((T)->state != THREAD_EXITED)
 369
 370 extern int thread_count (void);
 371
 372 /* Switch from one thread to another.  */
 373 extern void switch_to_thread (ptid_t ptid);
 374
 375 /* Marks thread PTID is running, or stopped.
 376    If PTID is minus_one_ptid, marks all threads.  */
 377 extern void set_running (ptid_t ptid, int running);
 378
 379 /* Marks or clears thread(s) PTID as having been requested to stop.
 380    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 381    ptid_is_pid(PTID) is true, applies to all threads of the process
 382    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 383    observer is called with PTID as argument.  */
 384 extern void set_stop_requested (ptid_t ptid, int stop);
 385
 386 /* NOTE: Since the thread state is not a boolean, most times, you do
 387    not want to check it with negation.  If you really want to check if
 388    the thread is stopped,
 389
 390     use (good):
 391
 392      if (is_stopped (ptid))
 393
 394     instead of (bad):
 395
 396      if (!is_running (ptid))
 397
 398    The latter also returns true on exited threads, most likelly not
 399    what you want.  */
 400
 401 /* Reports if in the frontend's perpective, thread PTID is running.  */
 402 extern int is_running (ptid_t ptid);
 403
 404 /* Is this thread listed, but known to have exited?  We keep it listed
 405    (but not visible) until it's safe to delete.  */
 406 extern int is_exited (ptid_t ptid);
 407
 408 /* In the frontend's perpective, is this thread stopped?  */
 409 extern int is_stopped (ptid_t ptid);
 410
 411 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 412    marks all threads.
 413
 414    Note that this is different from the running state.  See the
 415    description of state and executing fields of struct
 416    thread_info.  */
 417 extern void set_executing (ptid_t ptid, int executing);
 418
 419 /* Reports if thread PTID is executing.  */
 420 extern int is_executing (ptid_t ptid);
 421
 422 /* True if any (known or unknown) thread is or may be executing.  */
 423 extern int threads_are_executing (void);
 424
 425 /* Merge the executing property of thread PTID over to its thread
 426    state property (frontend running/stopped view).
 427
 428    "not executing" -> "stopped"
 429    "executing"     -> "running"
 430    "exited"        -> "exited"
 431
 432    If PTID is minus_one_ptid, go over all threads.
 433
 434    Notifications are only emitted if the thread state did change.  */
 435 extern void finish_thread_state (ptid_t ptid);
 436
 437 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 438    registered as a cleanup.  PTID_P points to the ptid_t that is
 439    passed to FINISH_THREAD_STATE.  */
 440 extern void finish_thread_state_cleanup (void *ptid_p);
 441
 442 /* Commands with a prefix of `thread'.  */
 443 extern struct cmd_list_element *thread_cmd_list;
 444
 445 /* Print notices on thread events (attach, detach, etc.), set with
 446    `set print thread-events'.  */
 447 extern int print_thread_events;
 448
 449 extern void print_thread_info (struct ui_out *uiout, char *threads,
 450                                int pid);
 451
 452 extern struct cleanup *make_cleanup_restore_current_thread (void);
 453
 454 /* Returns a pointer into the thread_info corresponding to
 455    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 456 extern struct thread_info* inferior_thread (void);
 457
 458 extern void update_thread_list (void);
 459
 460 /* Delete any thread the target says is no longer alive.  */
 461
 462 extern void prune_threads (void);
 463
 464 /* Return true if PC is in the stepping range of THREAD.  */
 465
 466 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 467
 468 extern struct thread_info *thread_list;
 469
 470 #endif /* GDBTHREAD_H */