gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2018 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 "btrace.h"
  30 #include "common/vec.h"
  31 #include "target/waitstatus.h"
  32 #include "cli/cli-utils.h"
  33 #include "common/refcounted-object.h"
  34 #include "common-gdbthread.h"
  35
  36 struct inferior;
  37
  38 /* Frontend view of the thread state.  Possible extensions: stepping,
  39    finishing, until(ling),...  */
  40 enum thread_state
  41 {
  42   THREAD_STOPPED,
  43   THREAD_RUNNING,
  44   THREAD_EXITED,
  45 };
  46
  47 /* STEP_OVER_ALL means step over all subroutine calls.
  48    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  49    STEP_OVER_NONE means don't step over any subroutine calls.  */
  50
  51 enum step_over_calls_kind
  52   {
  53     STEP_OVER_NONE,
  54     STEP_OVER_ALL,
  55     STEP_OVER_UNDEBUGGABLE
  56   };
  57
  58 /* Inferior thread specific part of `struct infcall_control_state'.
  59
  60    Inferior process counterpart is `struct inferior_control_state'.  */
  61
  62 struct thread_control_state
  63 {
  64   /* User/external stepping state.  */
  65
  66   /* Step-resume or longjmp-resume breakpoint.  */
  67   struct breakpoint *step_resume_breakpoint = nullptr;
  68
  69   /* Exception-resume breakpoint.  */
  70   struct breakpoint *exception_resume_breakpoint = nullptr;
  71
  72   /* Breakpoints used for software single stepping.  Plural, because
  73      it may have multiple locations.  E.g., if stepping over a
  74      conditional branch instruction we can't decode the condition for,
  75      we'll need to put a breakpoint at the branch destination, and
  76      another at the instruction after the branch.  */
  77   struct breakpoint *single_step_breakpoints = nullptr;
  78
  79   /* Range to single step within.
  80
  81      If this is nonzero, respond to a single-step signal by continuing
  82      to step if the pc is in this range.
  83
  84      If step_range_start and step_range_end are both 1, it means to
  85      step for a single instruction (FIXME: it might clean up
  86      wait_for_inferior in a minor way if this were changed to the
  87      address of the instruction and that address plus one.  But maybe
  88      not).  */
  89   CORE_ADDR step_range_start = 0;       /* Inclusive */
  90   CORE_ADDR step_range_end = 0;         /* Exclusive */
  91
  92   /* Function the thread was in as of last it started stepping.  */
  93   struct symbol *step_start_function = nullptr;
  94
  95   /* If GDB issues a target step request, and this is nonzero, the
  96      target should single-step this thread once, and then continue
  97      single-stepping it without GDB core involvement as long as the
  98      thread stops in the step range above.  If this is zero, the
  99      target should ignore the step range, and only issue one single
 100      step.  */
 101   int may_range_step = 0;
 102
 103   /* Stack frame address as of when stepping command was issued.
 104      This is how we know when we step into a subroutine call, and how
 105      to set the frame for the breakpoint used to step out.  */
 106   struct frame_id step_frame_id {};
 107
 108   /* Similarly, the frame ID of the underlying stack frame (skipping
 109      any inlined frames).  */
 110   struct frame_id step_stack_frame_id {};
 111
 112   /* Nonzero if we are presently stepping over a breakpoint.
 113
 114      If we hit a breakpoint or watchpoint, and then continue, we need
 115      to single step the current thread with breakpoints disabled, to
 116      avoid hitting the same breakpoint or watchpoint again.  And we
 117      should step just a single thread and keep other threads stopped,
 118      so that other threads don't miss breakpoints while they are
 119      removed.
 120
 121      So, this variable simultaneously means that we need to single
 122      step the current thread, keep other threads stopped, and that
 123      breakpoints should be removed while we step.
 124
 125      This variable is set either:
 126      - in proceed, when we resume inferior on user's explicit request
 127      - in keep_going, if handle_inferior_event decides we need to
 128      step over breakpoint.
 129
 130      The variable is cleared in normal_stop.  The proceed calls
 131      wait_for_inferior, which calls handle_inferior_event in a loop,
 132      and until wait_for_inferior exits, this variable is changed only
 133      by keep_going.  */
 134   int trap_expected = 0;
 135
 136   /* Nonzero if the thread is being proceeded for a "finish" command
 137      or a similar situation when return value should be printed.  */
 138   int proceed_to_finish = 0;
 139
 140   /* Nonzero if the thread is being proceeded for an inferior function
 141      call.  */
 142   int in_infcall = 0;
 143
 144   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 145
 146   /* Nonzero if stopped due to a step command.  */
 147   int stop_step = 0;
 148
 149   /* Chain containing status of breakpoint(s) the thread stopped
 150      at.  */
 151   bpstat stop_bpstat = nullptr;
 152
 153   /* Whether the command that started the thread was a stepping
 154      command.  This is used to decide whether "set scheduler-locking
 155      step" behaves like "on" or "off".  */
 156   int stepping_command = 0;
 157 };
 158
 159 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 160
 161 struct thread_suspend_state
 162 {
 163   /* Last signal that the inferior received (why it stopped).  When
 164      the thread is resumed, this signal is delivered.  Note: the
 165      target should not check whether the signal is in pass state,
 166      because the signal may have been explicitly passed with the
 167      "signal" command, which overrides "handle nopass".  If the signal
 168      should be suppressed, the core will take care of clearing this
 169      before the target is resumed.  */
 170   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 171
 172   /* The reason the thread last stopped, if we need to track it
 173      (breakpoint, watchpoint, etc.)  */
 174   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 175
 176   /* The waitstatus for this thread's last event.  */
 177   struct target_waitstatus waitstatus {};
 178   /* If true WAITSTATUS hasn't been handled yet.  */
 179   int waitstatus_pending_p = 0;
 180
 181   /* Record the pc of the thread the last time it stopped.  (This is
 182      not the current thread's PC as that may have changed since the
 183      last stop, e.g., "return" command, or "p $pc = 0xf000").
 184
 185      - If the thread's PC has not changed since the thread last
 186        stopped, then proceed skips a breakpoint at the current PC,
 187        otherwise we let the thread run into the breakpoint.
 188
 189      - If the thread has an unprocessed event pending, as indicated by
 190        waitstatus_pending_p, this is used in coordination with
 191        stop_reason: if the thread's PC has changed since the thread
 192        last stopped, a pending breakpoint waitstatus is discarded.
 193
 194      - If the thread is running, this is set to -1, to avoid leaving
 195        it with a stale value, to make it easier to catch bugs.  */
 196   CORE_ADDR stop_pc = 0;
 197 };
 198
 199 /* Base class for target-specific thread data.  */
 200 struct private_thread_info
 201 {
 202   virtual ~private_thread_info () = 0;
 203 };
 204
 205 /* Threads are intrusively refcounted objects.  Being the
 206    user-selected thread is normally considered an implicit strong
 207    reference and is thus not accounted in the refcount, unlike
 208    inferior objects.  This is necessary, because there's no "current
 209    thread" pointer.  Instead the current thread is inferred from the
 210    inferior_ptid global.  However, when GDB needs to remember the
 211    selected thread to later restore it, GDB bumps the thread object's
 212    refcount, to prevent something deleting the thread object before
 213    reverting back (e.g., due to a "kill" command).  If the thread
 214    meanwhile exits before being re-selected, then the thread object is
 215    left listed in the thread list, but marked with state
 216    THREAD_EXITED.  (See make_cleanup_restore_current_thread and
 217    delete_thread).  All other thread references are considered weak
 218    references.  Placing a thread in the thread list is an implicit
 219    strong reference, and is thus not accounted for in the thread's
 220    refcount.  */
 221
 222 class thread_info : public refcounted_object
 223 {
 224 public:
 225   explicit thread_info (inferior *inf, ptid_t ptid);
 226   ~thread_info ();
 227
 228   bool deletable () const;
 229
 230   /* Mark this thread as running and notify observers.  */
 231   void set_running (bool running);
 232
 233   struct thread_info *next = NULL;
 234   ptid_t ptid;                  /* "Actual process id";
 235                                     In fact, this may be overloaded with
 236                                     kernel thread id, etc.  */
 237
 238   /* Each thread has two GDB IDs.
 239
 240      a) The thread ID (Id).  This consists of the pair of:
 241
 242         - the number of the thread's inferior and,
 243
 244         - the thread's thread number in its inferior, aka, the
 245           per-inferior thread number.  This number is unique in the
 246           inferior but not unique between inferiors.
 247
 248      b) The global ID (GId).  This is a a single integer unique
 249         between all inferiors.
 250
 251      E.g.:
 252
 253       (gdb) info threads -gid
 254         Id    GId   Target Id   Frame
 255       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 256         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 257         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 258         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 259         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 260         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 261
 262      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 263      thread has its own unique global ID.  */
 264
 265   /* The thread's global GDB thread number.  This is exposed to MI,
 266      Python/Scheme, visible with "info threads -gid", and is also what
 267      the $_gthread convenience variable is bound to.  */
 268   int global_num;
 269
 270   /* The per-inferior thread number.  This is unique in the inferior
 271      the thread belongs to, but not unique between inferiors.  This is
 272      what the $_thread convenience variable is bound to.  */
 273   int per_inf_num;
 274
 275   /* The inferior this thread belongs to.  */
 276   struct inferior *inf;
 277
 278   /* The name of the thread, as specified by the user.  This is NULL
 279      if the thread does not have a user-given name.  */
 280   char *name = NULL;
 281
 282   /* Non-zero means the thread is executing.  Note: this is different
 283      from saying that there is an active target and we are stopped at
 284      a breakpoint, for instance.  This is a real indicator whether the
 285      thread is off and running.  */
 286   int executing = 0;
 287
 288   /* Non-zero if this thread is resumed from infrun's perspective.
 289      Note that a thread can be marked both as not-executing and
 290      resumed at the same time.  This happens if we try to resume a
 291      thread that has a wait status pending.  We shouldn't let the
 292      thread really run until that wait status has been processed, but
 293      we should not process that wait status if we didn't try to let
 294      the thread run.  */
 295   int resumed = 0;
 296
 297   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 298      THREAD_STOPPED states are different from EXECUTING.  When the
 299      thread is stopped internally while handling an internal event,
 300      like a software single-step breakpoint, EXECUTING will be false,
 301      but STATE will still be THREAD_RUNNING.  */
 302   enum thread_state state = THREAD_STOPPED;
 303
 304   /* State of GDB control of inferior thread execution.
 305      See `struct thread_control_state'.  */
 306   thread_control_state control;
 307
 308   /* State of inferior thread to restore after GDB is done with an inferior
 309      call.  See `struct thread_suspend_state'.  */
 310   thread_suspend_state suspend;
 311
 312   int current_line = 0;
 313   struct symtab *current_symtab = NULL;
 314
 315   /* Internal stepping state.  */
 316
 317   /* Record the pc of the thread the last time it was resumed.  (It
 318      can't be done on stop as the PC may change since the last stop,
 319      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 320      by proceed and keep_going, and among other things, it's used in
 321      adjust_pc_after_break to distinguish a hardware single-step
 322      SIGTRAP from a breakpoint SIGTRAP.  */
 323   CORE_ADDR prev_pc = 0;
 324
 325   /* Did we set the thread stepping a breakpoint instruction?  This is
 326      used in conjunction with PREV_PC to decide whether to adjust the
 327      PC.  */
 328   int stepped_breakpoint = 0;
 329
 330   /* Should we step over breakpoint next time keep_going is called?  */
 331   int stepping_over_breakpoint = 0;
 332
 333   /* Should we step over a watchpoint next time keep_going is called?
 334      This is needed on targets with non-continuable, non-steppable
 335      watchpoints.  */
 336   int stepping_over_watchpoint = 0;
 337
 338   /* Set to TRUE if we should finish single-stepping over a breakpoint
 339      after hitting the current step-resume breakpoint.  The context here
 340      is that GDB is to do `next' or `step' while signal arrives.
 341      When stepping over a breakpoint and signal arrives, GDB will attempt
 342      to skip signal handler, so it inserts a step_resume_breakpoint at the
 343      signal return address, and resume inferior.
 344      step_after_step_resume_breakpoint is set to TRUE at this moment in
 345      order to keep GDB in mind that there is still a breakpoint to step over
 346      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 347   int step_after_step_resume_breakpoint = 0;
 348
 349   /* Pointer to the state machine manager object that handles what is
 350      left to do for the thread's execution command after the target
 351      stops.  Several execution commands use it.  */
 352   struct thread_fsm *thread_fsm = NULL;
 353
 354   /* This is used to remember when a fork or vfork event was caught by
 355      a catchpoint, and thus the event is to be followed at the next
 356      resume of the thread, and not immediately.  */
 357   struct target_waitstatus pending_follow;
 358
 359   /* True if this thread has been explicitly requested to stop.  */
 360   int stop_requested = 0;
 361
 362   /* The initiating frame of a nexting operation, used for deciding
 363      which exceptions to intercept.  If it is null_frame_id no
 364      bp_longjmp or bp_exception but longjmp has been caught just for
 365      bp_longjmp_call_dummy.  */
 366   struct frame_id initiating_frame = null_frame_id;
 367
 368   /* Private data used by the target vector implementation.  */
 369   std::unique_ptr<private_thread_info> priv;
 370
 371   /* Branch trace information for this thread.  */
 372   struct btrace_thread_info btrace {};
 373
 374   /* Flag which indicates that the stack temporaries should be stored while
 375      evaluating expressions.  */
 376   bool stack_temporaries_enabled = false;
 377
 378   /* Values that are stored as temporaries on stack while evaluating
 379      expressions.  */
 380   std::vector<struct value *> stack_temporaries;
 381
 382   /* Step-over chain.  A thread is in the step-over queue if these are
 383      non-NULL.  If only a single thread is in the chain, then these
 384      fields point to self.  */
 385   struct thread_info *step_over_prev = NULL;
 386   struct thread_info *step_over_next = NULL;
 387 };
 388
 389 /* A gdb::ref_ptr pointer to a thread_info.  */
 390
 391 using thread_info_ref
 392   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 393
 394 /* Create an empty thread list, or empty the existing one.  */
 395 extern void init_thread_list (void);
 396
 397 /* Add a thread to the thread list, print a message
 398    that a new thread is found, and return the pointer to
 399    the new thread.  Caller my use this pointer to
 400    initialize the private thread data.  */
 401 extern struct thread_info *add_thread (ptid_t ptid);
 402
 403 /* Same as add_thread, but does not print a message
 404    about new thread.  */
 405 extern struct thread_info *add_thread_silent (ptid_t ptid);
 406
 407 /* Same as add_thread, and sets the private info.  */
 408 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 409                                                  struct private_thread_info *);
 410
 411 /* Delete an existing thread list entry.  */
 412 extern void delete_thread (struct thread_info *thread);
 413
 414 /* Delete an existing thread list entry, and be quiet about it.  Used
 415    after the process this thread having belonged to having already
 416    exited, for example.  */
 417 extern void delete_thread_silent (struct thread_info *thread);
 418
 419 /* Delete a step_resume_breakpoint from the thread database.  */
 420 extern void delete_step_resume_breakpoint (struct thread_info *);
 421
 422 /* Delete an exception_resume_breakpoint from the thread database.  */
 423 extern void delete_exception_resume_breakpoint (struct thread_info *);
 424
 425 /* Delete the single-step breakpoints of thread TP, if any.  */
 426 extern void delete_single_step_breakpoints (struct thread_info *tp);
 427
 428 /* Check if the thread has software single stepping breakpoints
 429    set.  */
 430 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 431
 432 /* Check whether the thread has software single stepping breakpoints
 433    set at PC.  */
 434 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 435                                                    const address_space *aspace,
 436                                                    CORE_ADDR addr);
 437
 438 /* Returns whether to show inferior-qualified thread IDs, or plain
 439    thread numbers.  Inferior-qualified IDs are shown whenever we have
 440    multiple inferiors, or the only inferior left has number > 1.  */
 441 extern int show_inferior_qualified_tids (void);
 442
 443 /* Return a string version of THR's thread ID.  If there are multiple
 444    inferiors, then this prints the inferior-qualifier form, otherwise
 445    it only prints the thread number.  The result is stored in a
 446    circular static buffer, NUMCELLS deep.  */
 447 const char *print_thread_id (struct thread_info *thr);
 448
 449 /* Boolean test for an already-known ptid.  */
 450 extern int in_thread_list (ptid_t ptid);
 451
 452 /* Boolean test for an already-known global thread id (GDB's homegrown
 453    global id, not the system's).  */
 454 extern int valid_global_thread_id (int global_id);
 455
 456 /* Search function to lookup a thread by 'pid'.  */
 457 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 458
 459 /* Search function to lookup a thread by 'ptid'.  Only searches in
 460    threads of INF.  */
 461 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 462
 463 /* Find thread by GDB global thread ID.  */
 464 struct thread_info *find_thread_global_id (int global_id);
 465
 466 /* Find thread by thread library specific handle in inferior INF.  */
 467 struct thread_info *find_thread_by_handle (struct value *thread_handle,
 468                                            struct inferior *inf);
 469
 470 /* Finds the first thread of the specified inferior.  */
 471 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 472
 473 /* Returns any thread of inferior INF, giving preference to the
 474    current thread.  */
 475 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 476
 477 /* Returns any non-exited thread of inferior INF, giving preference to
 478    the current thread, and to not executing threads.  */
 479 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 480
 481 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 482 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 483
 484 /* Iterator function to call a user-provided callback function
 485    once for each known thread.  */
 486 typedef int (*thread_callback_func) (struct thread_info *, void *);
 487 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 488
 489 /* Pull in the internals of the inferiors/threads ranges and
 490    iterators.  Must be done after struct thread_info is defined.  */
 491 #include "thread-iter.h"
 492
 493 /* Return a range that can be used to walk over all threads of all
 494    inferiors, with range-for.  Used like this:
 495
 496        for (thread_info *thr : all_threads ())
 497          { .... }
 498 */
 499 inline all_threads_range
 500 all_threads ()
 501 {
 502   return {};
 503 }
 504
 505 /* Likewise, but accept a filter PTID.  */
 506
 507 inline all_matching_threads_range
 508 all_threads (ptid_t filter_ptid)
 509 {
 510   return all_matching_threads_range (filter_ptid);
 511 }
 512
 513 /* Return a range that can be used to walk over all non-exited threads
 514    of all inferiors, with range-for.  FILTER_PTID can be used to
 515    filter out thread that don't match.  */
 516
 517 inline all_non_exited_threads_range
 518 all_non_exited_threads (ptid_t filter_ptid = minus_one_ptid)
 519 {
 520   return all_non_exited_threads_range (filter_ptid);
 521 }
 522
 523 /* Return a range that can be used to walk over all threads of all
 524    inferiors, with range-for, safely.  I.e., it is safe to delete the
 525    currently-iterated thread.  When combined with range-for, this
 526    allow convenient patterns like this:
 527
 528      for (thread_info *t : all_threads_safe ())
 529        if (some_condition ())
 530          delete f;
 531 */
 532
 533 inline all_threads_safe_range
 534 all_threads_safe ()
 535 {
 536   return all_threads_safe_range ();
 537 }
 538
 539 extern int thread_count (void);
 540
 541 /* Return true if we have any thread in any inferior.  */
 542 extern bool any_thread_p ();
 543
 544 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 545 extern void switch_to_thread (struct thread_info *thr);
 546
 547 /* Switch context to no thread selected.  */
 548 extern void switch_to_no_thread ();
 549
 550 /* Switch from one thread to another.  Does not read registers.  */
 551 extern void switch_to_thread_no_regs (struct thread_info *thread);
 552
 553 /* Marks or clears thread(s) PTID as resumed.  If PTID is
 554    MINUS_ONE_PTID, applies to all threads.  If ptid_is_pid(PTID) is
 555    true, applies to all threads of the process pointed at by PTID.  */
 556 extern void set_resumed (ptid_t ptid, int resumed);
 557
 558 /* Marks thread PTID is running, or stopped.
 559    If PTID is minus_one_ptid, marks all threads.  */
 560 extern void set_running (ptid_t ptid, int running);
 561
 562 /* Marks or clears thread(s) PTID as having been requested to stop.
 563    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 564    ptid_is_pid(PTID) is true, applies to all threads of the process
 565    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 566    observer is called with PTID as argument.  */
 567 extern void set_stop_requested (ptid_t ptid, int stop);
 568
 569 /* NOTE: Since the thread state is not a boolean, most times, you do
 570    not want to check it with negation.  If you really want to check if
 571    the thread is stopped,
 572
 573     use (good):
 574
 575      if (is_stopped (ptid))
 576
 577     instead of (bad):
 578
 579      if (!is_running (ptid))
 580
 581    The latter also returns true on exited threads, most likelly not
 582    what you want.  */
 583
 584 /* Reports if in the frontend's perpective, thread PTID is running.  */
 585 extern int is_running (ptid_t ptid);
 586
 587 /* Is this thread listed, but known to have exited?  We keep it listed
 588    (but not visible) until it's safe to delete.  */
 589 extern int is_exited (ptid_t ptid);
 590
 591 /* In the frontend's perpective, is this thread stopped?  */
 592 extern int is_stopped (ptid_t ptid);
 593
 594 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 595    marks all threads.
 596
 597    Note that this is different from the running state.  See the
 598    description of state and executing fields of struct
 599    thread_info.  */
 600 extern void set_executing (ptid_t ptid, int executing);
 601
 602 /* True if any (known or unknown) thread is or may be executing.  */
 603 extern int threads_are_executing (void);
 604
 605 /* Merge the executing property of thread PTID over to its thread
 606    state property (frontend running/stopped view).
 607
 608    "not executing" -> "stopped"
 609    "executing"     -> "running"
 610    "exited"        -> "exited"
 611
 612    If PTID is minus_one_ptid, go over all threads.
 613
 614    Notifications are only emitted if the thread state did change.  */
 615 extern void finish_thread_state (ptid_t ptid);
 616
 617 /* Calls finish_thread_state on scope exit, unless release() is called
 618    to disengage.  */
 619 class scoped_finish_thread_state
 620 {
 621 public:
 622   explicit scoped_finish_thread_state (ptid_t ptid)
 623     : m_ptid (ptid)
 624   {}
 625
 626   ~scoped_finish_thread_state ()
 627   {
 628     if (!m_released)
 629       finish_thread_state (m_ptid);
 630   }
 631
 632   /* Disengage.  */
 633   void release ()
 634   {
 635     m_released = true;
 636   }
 637
 638   DISABLE_COPY_AND_ASSIGN (scoped_finish_thread_state);
 639
 640 private:
 641   bool m_released = false;
 642   ptid_t m_ptid;
 643 };
 644
 645 /* Commands with a prefix of `thread'.  */
 646 extern struct cmd_list_element *thread_cmd_list;
 647
 648 extern void thread_command (const char *tidstr, int from_tty);
 649
 650 /* Print notices on thread events (attach, detach, etc.), set with
 651    `set print thread-events'.  */
 652 extern int print_thread_events;
 653
 654 /* Prints the list of threads and their details on UIOUT.  If
 655    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 656    print threads whose ID is included in the list.  If PID is not -1,
 657    only print threads from the process PID.  Otherwise, threads from
 658    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 659    NULL and PID is not -1, then the thread is printed if it belongs to
 660    the specified process.  Otherwise, an error is raised.  */
 661 extern void print_thread_info (struct ui_out *uiout, char *requested_threads,
 662                                int pid);
 663
 664 /* Save/restore current inferior/thread/frame.  */
 665
 666 class scoped_restore_current_thread
 667 {
 668 public:
 669   scoped_restore_current_thread ();
 670   ~scoped_restore_current_thread ();
 671
 672   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 673
 674 private:
 675   /* Use the "class" keyword here, because of a clash with a "thread_info"
 676      function in the Darwin API.  */
 677   class thread_info *m_thread;
 678   inferior *m_inf;
 679   frame_id m_selected_frame_id;
 680   int m_selected_frame_level;
 681   bool m_was_stopped;
 682 };
 683
 684 /* Returns a pointer into the thread_info corresponding to
 685    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 686 extern struct thread_info* inferior_thread (void);
 687
 688 extern void update_thread_list (void);
 689
 690 /* Delete any thread the target says is no longer alive.  */
 691
 692 extern void prune_threads (void);
 693
 694 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 695    does not consult the target about whether the thread is alive right
 696    now.  */
 697 extern void delete_exited_threads (void);
 698
 699 /* Return true if PC is in the stepping range of THREAD.  */
 700
 701 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 702
 703 /* Enable storing stack temporaries for thread THR and disable and
 704    clear the stack temporaries on destruction.  Holds a strong
 705    reference to THR.  */
 706
 707 class enable_thread_stack_temporaries
 708 {
 709 public:
 710
 711   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 712     : m_thr (thr)
 713   {
 714     gdb_assert (m_thr != NULL);
 715
 716     m_thr->incref ();
 717
 718     m_thr->stack_temporaries_enabled = true;
 719     m_thr->stack_temporaries.clear ();
 720   }
 721
 722   ~enable_thread_stack_temporaries ()
 723   {
 724     m_thr->stack_temporaries_enabled = false;
 725     m_thr->stack_temporaries.clear ();
 726
 727     m_thr->decref ();
 728   }
 729
 730   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 731
 732 private:
 733
 734   struct thread_info *m_thr;
 735 };
 736
 737 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 738
 739 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 740
 741 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 742
 743 extern bool value_in_thread_stack_temporaries (struct value *,
 744                                                struct thread_info *thr);
 745
 746 /* Add TP to the end of its inferior's pending step-over chain.  */
 747
 748 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 749
 750 /* Remove TP from its inferior's pending step-over chain.  */
 751
 752 extern void thread_step_over_chain_remove (struct thread_info *tp);
 753
 754 /* Return the next thread in the step-over chain starting at TP.  NULL
 755    if TP is the last entry in the chain.  */
 756
 757 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 758
 759 /* Return true if TP is in the step-over chain.  */
 760
 761 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 762
 763 /* Cancel any ongoing execution command.  */
 764
 765 extern void thread_cancel_execution_command (struct thread_info *thr);
 766
 767 /* Check whether it makes sense to access a register of the current
 768    thread at this point.  If not, throw an error (e.g., the thread is
 769    executing).  */
 770 extern void validate_registers_access (void);
 771
 772 /* Check whether it makes sense to access a register of THREAD at this point.
 773    Returns true if registers may be accessed; false otherwise.  */
 774 extern bool can_access_registers_thread (struct thread_info *thread);
 775
 776 /* Returns whether to show which thread hit the breakpoint, received a
 777    signal, etc. and ended up causing a user-visible stop.  This is
 778    true iff we ever detected multiple threads.  */
 779 extern int show_thread_that_caused_stop (void);
 780
 781 /* Print the message for a thread or/and frame selected.  */
 782 extern void print_selected_thread_frame (struct ui_out *uiout,
 783                                          user_selected_what selection);
 784
 785 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 786    Selects thread THR.  TIDSTR is the original string the thread ID
 787    was parsed from.  This is used in the error message if THR is not
 788    alive anymore.  */
 789 extern void thread_select (const char *tidstr, class thread_info *thr);
 790
 791 #endif /* GDBTHREAD_H */