gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2015 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 #include "common/vec.h"
  32
  33 /* Frontend view of the thread state.  Possible extensions: stepping,
  34    finishing, until(ling),...  */
  35 enum thread_state
  36 {
  37   THREAD_STOPPED,
  38   THREAD_RUNNING,
  39   THREAD_EXITED,
  40 };
  41
  42 /* Inferior thread specific part of `struct infcall_control_state'.
  43
  44    Inferior process counterpart is `struct inferior_control_state'.  */
  45
  46 struct thread_control_state
  47 {
  48   /* User/external stepping state.  */
  49
  50   /* Step-resume or longjmp-resume breakpoint.  */
  51   struct breakpoint *step_resume_breakpoint;
  52
  53   /* Exception-resume breakpoint.  */
  54   struct breakpoint *exception_resume_breakpoint;
  55
  56   /* Breakpoints used for software single stepping.  Plural, because
  57      it may have multiple locations.  E.g., if stepping over a
  58      conditional branch instruction we can't decode the condition for,
  59      we'll need to put a breakpoint at the branch destination, and
  60      another at the instruction after the branch.  */
  61   struct breakpoint *single_step_breakpoints;
  62
  63   /* Range to single step within.
  64
  65      If this is nonzero, respond to a single-step signal by continuing
  66      to step if the pc is in this range.
  67
  68      If step_range_start and step_range_end are both 1, it means to
  69      step for a single instruction (FIXME: it might clean up
  70      wait_for_inferior in a minor way if this were changed to the
  71      address of the instruction and that address plus one.  But maybe
  72      not).  */
  73   CORE_ADDR step_range_start;   /* Inclusive */
  74   CORE_ADDR step_range_end;     /* Exclusive */
  75
  76   /* Function the thread was in as of last it started stepping.  */
  77   struct symbol *step_start_function;
  78
  79   /* If GDB issues a target step request, and this is nonzero, the
  80      target should single-step this thread once, and then continue
  81      single-stepping it without GDB core involvement as long as the
  82      thread stops in the step range above.  If this is zero, the
  83      target should ignore the step range, and only issue one single
  84      step.  */
  85   int may_range_step;
  86
  87   /* Stack frame address as of when stepping command was issued.
  88      This is how we know when we step into a subroutine call, and how
  89      to set the frame for the breakpoint used to step out.  */
  90   struct frame_id step_frame_id;
  91
  92   /* Similarly, the frame ID of the underlying stack frame (skipping
  93      any inlined frames).  */
  94   struct frame_id step_stack_frame_id;
  95
  96   /* Nonzero if we are presently stepping over a breakpoint.
  97
  98      If we hit a breakpoint or watchpoint, and then continue, we need
  99      to single step the current thread with breakpoints disabled, to
 100      avoid hitting the same breakpoint or watchpoint again.  And we
 101      should step just a single thread and keep other threads stopped,
 102      so that other threads don't miss breakpoints while they are
 103      removed.
 104
 105      So, this variable simultaneously means that we need to single
 106      step the current thread, keep other threads stopped, and that
 107      breakpoints should be removed while we step.
 108
 109      This variable is set either:
 110      - in proceed, when we resume inferior on user's explicit request
 111      - in keep_going, if handle_inferior_event decides we need to
 112      step over breakpoint.
 113
 114      The variable is cleared in normal_stop.  The proceed calls
 115      wait_for_inferior, which calls handle_inferior_event in a loop,
 116      and until wait_for_inferior exits, this variable is changed only
 117      by keep_going.  */
 118   int trap_expected;
 119
 120   /* Nonzero if the thread is being proceeded for a "finish" command
 121      or a similar situation when return value should be printed.  */
 122   int proceed_to_finish;
 123
 124   /* Nonzero if the thread is being proceeded for an inferior function
 125      call.  */
 126   int in_infcall;
 127
 128   enum step_over_calls_kind step_over_calls;
 129
 130   /* Nonzero if stopped due to a step command.  */
 131   int stop_step;
 132
 133   /* Chain containing status of breakpoint(s) the thread stopped
 134      at.  */
 135   bpstat stop_bpstat;
 136
 137   /* The interpreter that issued the execution command.  NULL if the
 138      thread was resumed as a result of a command applied to some other
 139      thread (e.g., "next" with scheduler-locking off).  */
 140   struct interp *command_interp;
 141
 142   /* Whether the command that started the thread was a stepping
 143      command.  This is used to decide whether "set scheduler-locking
 144      step" behaves like "on" or "off".  */
 145   int stepping_command;
 146 };
 147
 148 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 149
 150 struct thread_suspend_state
 151 {
 152   /* Last signal that the inferior received (why it stopped).  When
 153      the thread is resumed, this signal is delivered.  Note: the
 154      target should not check whether the signal is in pass state,
 155      because the signal may have been explicitly passed with the
 156      "signal" command, which overrides "handle nopass".  If the signal
 157      should be suppressed, the core will take care of clearing this
 158      before the target is resumed.  */
 159   enum gdb_signal stop_signal;
 160 };
 161
 162 typedef struct value *value_ptr;
 163 DEF_VEC_P (value_ptr);
 164 typedef VEC (value_ptr) value_vec;
 165
 166 struct thread_info
 167 {
 168   struct thread_info *next;
 169   ptid_t ptid;                  /* "Actual process id";
 170                                     In fact, this may be overloaded with
 171                                     kernel thread id, etc.  */
 172   int num;                      /* Convenient handle (GDB thread id) */
 173
 174   /* The name of the thread, as specified by the user.  This is NULL
 175      if the thread does not have a user-given name.  */
 176   char *name;
 177
 178   /* Non-zero means the thread is executing.  Note: this is different
 179      from saying that there is an active target and we are stopped at
 180      a breakpoint, for instance.  This is a real indicator whether the
 181      thread is off and running.  */
 182   int executing;
 183
 184   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 185      THREAD_STOPPED states are different from EXECUTING.  When the
 186      thread is stopped internally while handling an internal event,
 187      like a software single-step breakpoint, EXECUTING will be false,
 188      but STATE will still be THREAD_RUNNING.  */
 189   enum thread_state state;
 190
 191   /* If this is > 0, then it means there's code out there that relies
 192      on this thread being listed.  Don't delete it from the lists even
 193      if we detect it exiting.  */
 194   int refcount;
 195
 196   /* State of GDB control of inferior thread execution.
 197      See `struct thread_control_state'.  */
 198   struct thread_control_state control;
 199
 200   /* State of inferior thread to restore after GDB is done with an inferior
 201      call.  See `struct thread_suspend_state'.  */
 202   struct thread_suspend_state suspend;
 203
 204   int current_line;
 205   struct symtab *current_symtab;
 206
 207   /* Internal stepping state.  */
 208
 209   /* Record the pc of the thread the last time it stopped.  This is
 210      maintained by proceed and keep_going, and used in
 211      adjust_pc_after_break to distinguish a hardware single-step
 212      SIGTRAP from a breakpoint SIGTRAP.  */
 213   CORE_ADDR prev_pc;
 214
 215   /* Did we set the thread stepping a breakpoint instruction?  This is
 216      used in conjunction with PREV_PC to decide whether to adjust the
 217      PC.  */
 218   int stepped_breakpoint;
 219
 220   /* Should we step over breakpoint next time keep_going is called?  */
 221   int stepping_over_breakpoint;
 222
 223   /* Should we step over a watchpoint next time keep_going is called?
 224      This is needed on targets with non-continuable, non-steppable
 225      watchpoints.  */
 226   int stepping_over_watchpoint;
 227
 228   /* Set to TRUE if we should finish single-stepping over a breakpoint
 229      after hitting the current step-resume breakpoint.  The context here
 230      is that GDB is to do `next' or `step' while signal arrives.
 231      When stepping over a breakpoint and signal arrives, GDB will attempt
 232      to skip signal handler, so it inserts a step_resume_breakpoint at the
 233      signal return address, and resume inferior.
 234      step_after_step_resume_breakpoint is set to TRUE at this moment in
 235      order to keep GDB in mind that there is still a breakpoint to step over
 236      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 237   int step_after_step_resume_breakpoint;
 238
 239   /* Per-thread command support.  */
 240
 241   /* Pointer to what is left to do for an execution command after the
 242      target stops.  Used only in asynchronous mode, by targets that
 243      support async execution.  Several execution commands use it.  */
 244   struct continuation *continuations;
 245
 246   /* Similar to the above, but used when a single execution command
 247      requires several resume/stop iterations.  Used by the step
 248      command.  */
 249   struct continuation *intermediate_continuations;
 250
 251   /* If stepping, nonzero means step count is > 1 so don't print frame
 252      next time inferior stops if it stops due to stepping.  */
 253   int step_multi;
 254
 255   /* This is used to remember when a fork or vfork event was caught by
 256      a catchpoint, and thus the event is to be followed at the next
 257      resume of the thread, and not immediately.  */
 258   struct target_waitstatus pending_follow;
 259
 260   /* True if this thread has been explicitly requested to stop.  */
 261   int stop_requested;
 262
 263   /* The initiating frame of a nexting operation, used for deciding
 264      which exceptions to intercept.  If it is null_frame_id no
 265      bp_longjmp or bp_exception but longjmp has been caught just for
 266      bp_longjmp_call_dummy.  */
 267   struct frame_id initiating_frame;
 268
 269   /* Private data used by the target vector implementation.  */
 270   struct private_thread_info *priv;
 271
 272   /* Function that is called to free PRIVATE.  If this is NULL, then
 273      xfree will be called on PRIVATE.  */
 274   void (*private_dtor) (struct private_thread_info *);
 275
 276   /* Branch trace information for this thread.  */
 277   struct btrace_thread_info btrace;
 278
 279   /* Flag which indicates that the stack temporaries should be stored while
 280      evaluating expressions.  */
 281   int stack_temporaries_enabled;
 282
 283   /* Values that are stored as temporaries on stack while evaluating
 284      expressions.  */
 285   value_vec *stack_temporaries;
 286 };
 287
 288 /* Create an empty thread list, or empty the existing one.  */
 289 extern void init_thread_list (void);
 290
 291 /* Add a thread to the thread list, print a message
 292    that a new thread is found, and return the pointer to
 293    the new thread.  Caller my use this pointer to
 294    initialize the private thread data.  */
 295 extern struct thread_info *add_thread (ptid_t ptid);
 296
 297 /* Same as add_thread, but does not print a message
 298    about new thread.  */
 299 extern struct thread_info *add_thread_silent (ptid_t ptid);
 300
 301 /* Same as add_thread, and sets the private info.  */
 302 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 303                                                  struct private_thread_info *);
 304
 305 /* Delete an existing thread list entry.  */
 306 extern void delete_thread (ptid_t);
 307
 308 /* Delete an existing thread list entry, and be quiet about it.  Used
 309    after the process this thread having belonged to having already
 310    exited, for example.  */
 311 extern void delete_thread_silent (ptid_t);
 312
 313 /* Delete a step_resume_breakpoint from the thread database.  */
 314 extern void delete_step_resume_breakpoint (struct thread_info *);
 315
 316 /* Delete an exception_resume_breakpoint from the thread database.  */
 317 extern void delete_exception_resume_breakpoint (struct thread_info *);
 318
 319 /* Delete the single-step breakpoints of thread TP, if any.  */
 320 extern void delete_single_step_breakpoints (struct thread_info *tp);
 321
 322 /* Check if the thread has software single stepping breakpoints
 323    set.  */
 324 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 325
 326 /* Check whether the thread has software single stepping breakpoints
 327    set at PC.  */
 328 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 329                                                    struct address_space *aspace,
 330                                                    CORE_ADDR addr);
 331
 332 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 333    into a "pid" (which may be overloaded with extra thread information).  */
 334 extern ptid_t thread_id_to_pid (int);
 335
 336 /* Translate a 'pid' (which may be overloaded with extra thread information)
 337    into the integer thread id (GDB's homegrown id, not the system's).  */
 338 extern int pid_to_thread_id (ptid_t ptid);
 339
 340 /* Boolean test for an already-known pid (which may be overloaded with
 341    extra thread information).  */
 342 extern int in_thread_list (ptid_t ptid);
 343
 344 /* Boolean test for an already-known thread id (GDB's homegrown id,
 345    not the system's).  */
 346 extern int valid_thread_id (int thread);
 347
 348 /* Search function to lookup a thread by 'pid'.  */
 349 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 350
 351 /* Find thread by GDB user-visible thread number.  */
 352 struct thread_info *find_thread_id (int num);
 353
 354 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 355    returns the first thread in the list.  */
 356 struct thread_info *first_thread_of_process (int pid);
 357
 358 /* Returns any thread of process PID, giving preference to the current
 359    thread.  */
 360 extern struct thread_info *any_thread_of_process (int pid);
 361
 362 /* Returns any non-exited thread of process PID, giving preference to
 363    the current thread, and to not executing threads.  */
 364 extern struct thread_info *any_live_thread_of_process (int pid);
 365
 366 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 367 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 368
 369 /* Iterator function to call a user-provided callback function
 370    once for each known thread.  */
 371 typedef int (*thread_callback_func) (struct thread_info *, void *);
 372 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 373
 374 /* Traverse all threads, except those that have THREAD_EXITED
 375    state.  */
 376
 377 #define ALL_NON_EXITED_THREADS(T)                               \
 378   for (T = thread_list; T; T = T->next) \
 379     if ((T)->state != THREAD_EXITED)
 380
 381 /* Traverse all threads, including those that have THREAD_EXITED
 382    state.  Allows deleting the currently iterated thread.  */
 383 #define ALL_THREADS_SAFE(T, TMP)        \
 384   for ((T) = thread_list;                       \
 385        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 386        (T) = (TMP))
 387
 388 extern int thread_count (void);
 389
 390 /* Switch from one thread to another.  */
 391 extern void switch_to_thread (ptid_t ptid);
 392
 393 /* Marks thread PTID is running, or stopped.
 394    If PTID is minus_one_ptid, marks all threads.  */
 395 extern void set_running (ptid_t ptid, int running);
 396
 397 /* Marks or clears thread(s) PTID as having been requested to stop.
 398    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 399    ptid_is_pid(PTID) is true, applies to all threads of the process
 400    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 401    observer is called with PTID as argument.  */
 402 extern void set_stop_requested (ptid_t ptid, int stop);
 403
 404 /* NOTE: Since the thread state is not a boolean, most times, you do
 405    not want to check it with negation.  If you really want to check if
 406    the thread is stopped,
 407
 408     use (good):
 409
 410      if (is_stopped (ptid))
 411
 412     instead of (bad):
 413
 414      if (!is_running (ptid))
 415
 416    The latter also returns true on exited threads, most likelly not
 417    what you want.  */
 418
 419 /* Reports if in the frontend's perpective, thread PTID is running.  */
 420 extern int is_running (ptid_t ptid);
 421
 422 /* Is this thread listed, but known to have exited?  We keep it listed
 423    (but not visible) until it's safe to delete.  */
 424 extern int is_exited (ptid_t ptid);
 425
 426 /* In the frontend's perpective, is this thread stopped?  */
 427 extern int is_stopped (ptid_t ptid);
 428
 429 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 430    marks all threads.
 431
 432    Note that this is different from the running state.  See the
 433    description of state and executing fields of struct
 434    thread_info.  */
 435 extern void set_executing (ptid_t ptid, int executing);
 436
 437 /* Reports if thread PTID is executing.  */
 438 extern int is_executing (ptid_t ptid);
 439
 440 /* True if any (known or unknown) thread is or may be executing.  */
 441 extern int threads_are_executing (void);
 442
 443 /* Merge the executing property of thread PTID over to its thread
 444    state property (frontend running/stopped view).
 445
 446    "not executing" -> "stopped"
 447    "executing"     -> "running"
 448    "exited"        -> "exited"
 449
 450    If PTID is minus_one_ptid, go over all threads.
 451
 452    Notifications are only emitted if the thread state did change.  */
 453 extern void finish_thread_state (ptid_t ptid);
 454
 455 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 456    registered as a cleanup.  PTID_P points to the ptid_t that is
 457    passed to FINISH_THREAD_STATE.  */
 458 extern void finish_thread_state_cleanup (void *ptid_p);
 459
 460 /* Commands with a prefix of `thread'.  */
 461 extern struct cmd_list_element *thread_cmd_list;
 462
 463 extern void thread_command (char *tidstr, int from_tty);
 464
 465 /* Print notices on thread events (attach, detach, etc.), set with
 466    `set print thread-events'.  */
 467 extern int print_thread_events;
 468
 469 extern void print_thread_info (struct ui_out *uiout, char *threads,
 470                                int pid);
 471
 472 extern struct cleanup *make_cleanup_restore_current_thread (void);
 473
 474 /* Returns a pointer into the thread_info corresponding to
 475    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 476 extern struct thread_info* inferior_thread (void);
 477
 478 extern void update_thread_list (void);
 479
 480 /* Delete any thread the target says is no longer alive.  */
 481
 482 extern void prune_threads (void);
 483
 484 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 485    does not consult the target about whether the thread is alive right
 486    now.  */
 487 extern void delete_exited_threads (void);
 488
 489 /* Return true if PC is in the stepping range of THREAD.  */
 490
 491 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 492
 493 extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid);
 494
 495 extern int thread_stack_temporaries_enabled_p (ptid_t ptid);
 496
 497 extern void push_thread_stack_temporary (ptid_t ptid, struct value *v);
 498
 499 extern struct value *get_last_thread_stack_temporary (ptid_t);
 500
 501 extern int value_in_thread_stack_temporaries (struct value *, ptid_t);
 502
 503 extern struct thread_info *thread_list;
 504
 505 #endif /* GDBTHREAD_H */