gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2020 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 "target/waitstatus.h"
  31 #include "cli/cli-utils.h"
  32 #include "gdbsupport/refcounted-object.h"
  33 #include "gdbsupport/common-gdbthread.h"
  34 #include "gdbsupport/forward-scope-exit.h"
  35
  36 struct inferior;
  37
  38 /* Frontend view of the thread state.  Possible extensions: stepping,
  39    finishing, until(ling),...
  40
  41    NOTE: Since the thread state is not a boolean, most times, you do
  42    not want to check it with negation.  If you really want to check if
  43    the thread is stopped,
  44
  45     use (good):
  46
  47      if (tp->state == THREAD_STOPPED)
  48
  49     instead of (bad):
  50
  51      if (tp->state != THREAD_RUNNING)
  52
  53    The latter is also true for exited threads, most likely not what
  54    you want.  */
  55 enum thread_state
  56 {
  57   /* In the frontend's perpective, the thread is stopped.  */
  58   THREAD_STOPPED,
  59
  60   /* In the frontend's perpective, the thread is running.  */
  61   THREAD_RUNNING,
  62
  63   /* The thread is listed, but known to have exited.  We keep it
  64      listed (but not visible) until it's safe to delete it.  */
  65   THREAD_EXITED,
  66 };
  67
  68 /* STEP_OVER_ALL means step over all subroutine calls.
  69    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  70    STEP_OVER_NONE means don't step over any subroutine calls.  */
  71
  72 enum step_over_calls_kind
  73   {
  74     STEP_OVER_NONE,
  75     STEP_OVER_ALL,
  76     STEP_OVER_UNDEBUGGABLE
  77   };
  78
  79 /* Inferior thread specific part of `struct infcall_control_state'.
  80
  81    Inferior process counterpart is `struct inferior_control_state'.  */
  82
  83 struct thread_control_state
  84 {
  85   /* User/external stepping state.  */
  86
  87   /* Step-resume or longjmp-resume breakpoint.  */
  88   struct breakpoint *step_resume_breakpoint = nullptr;
  89
  90   /* Exception-resume breakpoint.  */
  91   struct breakpoint *exception_resume_breakpoint = nullptr;
  92
  93   /* Breakpoints used for software single stepping.  Plural, because
  94      it may have multiple locations.  E.g., if stepping over a
  95      conditional branch instruction we can't decode the condition for,
  96      we'll need to put a breakpoint at the branch destination, and
  97      another at the instruction after the branch.  */
  98   struct breakpoint *single_step_breakpoints = nullptr;
  99
 100   /* Range to single step within.
 101
 102      If this is nonzero, respond to a single-step signal by continuing
 103      to step if the pc is in this range.
 104
 105      If step_range_start and step_range_end are both 1, it means to
 106      step for a single instruction (FIXME: it might clean up
 107      wait_for_inferior in a minor way if this were changed to the
 108      address of the instruction and that address plus one.  But maybe
 109      not).  */
 110   CORE_ADDR step_range_start = 0;       /* Inclusive */
 111   CORE_ADDR step_range_end = 0;         /* Exclusive */
 112
 113   /* Function the thread was in as of last it started stepping.  */
 114   struct symbol *step_start_function = nullptr;
 115
 116   /* If GDB issues a target step request, and this is nonzero, the
 117      target should single-step this thread once, and then continue
 118      single-stepping it without GDB core involvement as long as the
 119      thread stops in the step range above.  If this is zero, the
 120      target should ignore the step range, and only issue one single
 121      step.  */
 122   int may_range_step = 0;
 123
 124   /* Stack frame address as of when stepping command was issued.
 125      This is how we know when we step into a subroutine call, and how
 126      to set the frame for the breakpoint used to step out.  */
 127   struct frame_id step_frame_id {};
 128
 129   /* Similarly, the frame ID of the underlying stack frame (skipping
 130      any inlined frames).  */
 131   struct frame_id step_stack_frame_id {};
 132
 133   /* Nonzero if we are presently stepping over a breakpoint.
 134
 135      If we hit a breakpoint or watchpoint, and then continue, we need
 136      to single step the current thread with breakpoints disabled, to
 137      avoid hitting the same breakpoint or watchpoint again.  And we
 138      should step just a single thread and keep other threads stopped,
 139      so that other threads don't miss breakpoints while they are
 140      removed.
 141
 142      So, this variable simultaneously means that we need to single
 143      step the current thread, keep other threads stopped, and that
 144      breakpoints should be removed while we step.
 145
 146      This variable is set either:
 147      - in proceed, when we resume inferior on user's explicit request
 148      - in keep_going, if handle_inferior_event decides we need to
 149      step over breakpoint.
 150
 151      The variable is cleared in normal_stop.  The proceed calls
 152      wait_for_inferior, which calls handle_inferior_event in a loop,
 153      and until wait_for_inferior exits, this variable is changed only
 154      by keep_going.  */
 155   int trap_expected = 0;
 156
 157   /* Nonzero if the thread is being proceeded for a "finish" command
 158      or a similar situation when return value should be printed.  */
 159   int proceed_to_finish = 0;
 160
 161   /* Nonzero if the thread is being proceeded for an inferior function
 162      call.  */
 163   int in_infcall = 0;
 164
 165   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 166
 167   /* Nonzero if stopped due to a step command.  */
 168   int stop_step = 0;
 169
 170   /* Chain containing status of breakpoint(s) the thread stopped
 171      at.  */
 172   bpstat stop_bpstat = nullptr;
 173
 174   /* Whether the command that started the thread was a stepping
 175      command.  This is used to decide whether "set scheduler-locking
 176      step" behaves like "on" or "off".  */
 177   int stepping_command = 0;
 178 };
 179
 180 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 181
 182 struct thread_suspend_state
 183 {
 184   /* Last signal that the inferior received (why it stopped).  When
 185      the thread is resumed, this signal is delivered.  Note: the
 186      target should not check whether the signal is in pass state,
 187      because the signal may have been explicitly passed with the
 188      "signal" command, which overrides "handle nopass".  If the signal
 189      should be suppressed, the core will take care of clearing this
 190      before the target is resumed.  */
 191   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 192
 193   /* The reason the thread last stopped, if we need to track it
 194      (breakpoint, watchpoint, etc.)  */
 195   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 196
 197   /* The waitstatus for this thread's last event.  */
 198   struct target_waitstatus waitstatus {};
 199   /* If true WAITSTATUS hasn't been handled yet.  */
 200   int waitstatus_pending_p = 0;
 201
 202   /* Record the pc of the thread the last time it stopped.  (This is
 203      not the current thread's PC as that may have changed since the
 204      last stop, e.g., "return" command, or "p $pc = 0xf000").
 205
 206      - If the thread's PC has not changed since the thread last
 207        stopped, then proceed skips a breakpoint at the current PC,
 208        otherwise we let the thread run into the breakpoint.
 209
 210      - If the thread has an unprocessed event pending, as indicated by
 211        waitstatus_pending_p, this is used in coordination with
 212        stop_reason: if the thread's PC has changed since the thread
 213        last stopped, a pending breakpoint waitstatus is discarded.
 214
 215      - If the thread is running, this is set to -1, to avoid leaving
 216        it with a stale value, to make it easier to catch bugs.  */
 217   CORE_ADDR stop_pc = 0;
 218 };
 219
 220 /* Base class for target-specific thread data.  */
 221 struct private_thread_info
 222 {
 223   virtual ~private_thread_info () = 0;
 224 };
 225
 226 /* Threads are intrusively refcounted objects.  Being the
 227    user-selected thread is normally considered an implicit strong
 228    reference and is thus not accounted in the refcount, unlike
 229    inferior objects.  This is necessary, because there's no "current
 230    thread" pointer.  Instead the current thread is inferred from the
 231    inferior_ptid global.  However, when GDB needs to remember the
 232    selected thread to later restore it, GDB bumps the thread object's
 233    refcount, to prevent something deleting the thread object before
 234    reverting back (e.g., due to a "kill" command).  If the thread
 235    meanwhile exits before being re-selected, then the thread object is
 236    left listed in the thread list, but marked with state
 237    THREAD_EXITED.  (See scoped_restore_current_thread and
 238    delete_thread).  All other thread references are considered weak
 239    references.  Placing a thread in the thread list is an implicit
 240    strong reference, and is thus not accounted for in the thread's
 241    refcount.  */
 242
 243 class thread_info : public refcounted_object
 244 {
 245 public:
 246   explicit thread_info (inferior *inf, ptid_t ptid);
 247   ~thread_info ();
 248
 249   bool deletable () const;
 250
 251   /* Mark this thread as running and notify observers.  */
 252   void set_running (bool running);
 253
 254   struct thread_info *next = NULL;
 255   ptid_t ptid;                  /* "Actual process id";
 256                                     In fact, this may be overloaded with
 257                                     kernel thread id, etc.  */
 258
 259   /* Each thread has two GDB IDs.
 260
 261      a) The thread ID (Id).  This consists of the pair of:
 262
 263         - the number of the thread's inferior and,
 264
 265         - the thread's thread number in its inferior, aka, the
 266           per-inferior thread number.  This number is unique in the
 267           inferior but not unique between inferiors.
 268
 269      b) The global ID (GId).  This is a a single integer unique
 270         between all inferiors.
 271
 272      E.g.:
 273
 274       (gdb) info threads -gid
 275         Id    GId   Target Id   Frame
 276       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 277         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 278         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 279         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 280         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 281         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 282
 283      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 284      thread has its own unique global ID.  */
 285
 286   /* The thread's global GDB thread number.  This is exposed to MI,
 287      Python/Scheme, visible with "info threads -gid", and is also what
 288      the $_gthread convenience variable is bound to.  */
 289   int global_num;
 290
 291   /* The per-inferior thread number.  This is unique in the inferior
 292      the thread belongs to, but not unique between inferiors.  This is
 293      what the $_thread convenience variable is bound to.  */
 294   int per_inf_num;
 295
 296   /* The inferior this thread belongs to.  */
 297   struct inferior *inf;
 298
 299   /* The name of the thread, as specified by the user.  This is NULL
 300      if the thread does not have a user-given name.  */
 301   char *name = NULL;
 302
 303   /* Non-zero means the thread is executing.  Note: this is different
 304      from saying that there is an active target and we are stopped at
 305      a breakpoint, for instance.  This is a real indicator whether the
 306      thread is off and running.  */
 307   int executing = 0;
 308
 309   /* Non-zero if this thread is resumed from infrun's perspective.
 310      Note that a thread can be marked both as not-executing and
 311      resumed at the same time.  This happens if we try to resume a
 312      thread that has a wait status pending.  We shouldn't let the
 313      thread really run until that wait status has been processed, but
 314      we should not process that wait status if we didn't try to let
 315      the thread run.  */
 316   int resumed = 0;
 317
 318   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 319      THREAD_STOPPED states are different from EXECUTING.  When the
 320      thread is stopped internally while handling an internal event,
 321      like a software single-step breakpoint, EXECUTING will be false,
 322      but STATE will still be THREAD_RUNNING.  */
 323   enum thread_state state = THREAD_STOPPED;
 324
 325   /* State of GDB control of inferior thread execution.
 326      See `struct thread_control_state'.  */
 327   thread_control_state control;
 328
 329   /* State of inferior thread to restore after GDB is done with an inferior
 330      call.  See `struct thread_suspend_state'.  */
 331   thread_suspend_state suspend;
 332
 333   int current_line = 0;
 334   struct symtab *current_symtab = NULL;
 335
 336   /* Internal stepping state.  */
 337
 338   /* Record the pc of the thread the last time it was resumed.  (It
 339      can't be done on stop as the PC may change since the last stop,
 340      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 341      by proceed and keep_going, and among other things, it's used in
 342      adjust_pc_after_break to distinguish a hardware single-step
 343      SIGTRAP from a breakpoint SIGTRAP.  */
 344   CORE_ADDR prev_pc = 0;
 345
 346   /* Did we set the thread stepping a breakpoint instruction?  This is
 347      used in conjunction with PREV_PC to decide whether to adjust the
 348      PC.  */
 349   int stepped_breakpoint = 0;
 350
 351   /* Should we step over breakpoint next time keep_going is called?  */
 352   int stepping_over_breakpoint = 0;
 353
 354   /* Should we step over a watchpoint next time keep_going is called?
 355      This is needed on targets with non-continuable, non-steppable
 356      watchpoints.  */
 357   int stepping_over_watchpoint = 0;
 358
 359   /* Set to TRUE if we should finish single-stepping over a breakpoint
 360      after hitting the current step-resume breakpoint.  The context here
 361      is that GDB is to do `next' or `step' while signal arrives.
 362      When stepping over a breakpoint and signal arrives, GDB will attempt
 363      to skip signal handler, so it inserts a step_resume_breakpoint at the
 364      signal return address, and resume inferior.
 365      step_after_step_resume_breakpoint is set to TRUE at this moment in
 366      order to keep GDB in mind that there is still a breakpoint to step over
 367      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 368   int step_after_step_resume_breakpoint = 0;
 369
 370   /* Pointer to the state machine manager object that handles what is
 371      left to do for the thread's execution command after the target
 372      stops.  Several execution commands use it.  */
 373   struct thread_fsm *thread_fsm = NULL;
 374
 375   /* This is used to remember when a fork or vfork event was caught by
 376      a catchpoint, and thus the event is to be followed at the next
 377      resume of the thread, and not immediately.  */
 378   struct target_waitstatus pending_follow;
 379
 380   /* True if this thread has been explicitly requested to stop.  */
 381   int stop_requested = 0;
 382
 383   /* The initiating frame of a nexting operation, used for deciding
 384      which exceptions to intercept.  If it is null_frame_id no
 385      bp_longjmp or bp_exception but longjmp has been caught just for
 386      bp_longjmp_call_dummy.  */
 387   struct frame_id initiating_frame = null_frame_id;
 388
 389   /* Private data used by the target vector implementation.  */
 390   std::unique_ptr<private_thread_info> priv;
 391
 392   /* Branch trace information for this thread.  */
 393   struct btrace_thread_info btrace {};
 394
 395   /* Flag which indicates that the stack temporaries should be stored while
 396      evaluating expressions.  */
 397   bool stack_temporaries_enabled = false;
 398
 399   /* Values that are stored as temporaries on stack while evaluating
 400      expressions.  */
 401   std::vector<struct value *> stack_temporaries;
 402
 403   /* Step-over chain.  A thread is in the step-over queue if these are
 404      non-NULL.  If only a single thread is in the chain, then these
 405      fields point to self.  */
 406   struct thread_info *step_over_prev = NULL;
 407   struct thread_info *step_over_next = NULL;
 408 };
 409
 410 /* A gdb::ref_ptr pointer to a thread_info.  */
 411
 412 using thread_info_ref
 413   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 414
 415 /* Create an empty thread list, or empty the existing one.  */
 416 extern void init_thread_list (void);
 417
 418 /* Add a thread to the thread list, print a message
 419    that a new thread is found, and return the pointer to
 420    the new thread.  Caller my use this pointer to
 421    initialize the private thread data.  */
 422 extern struct thread_info *add_thread (ptid_t ptid);
 423
 424 /* Same as add_thread, but does not print a message
 425    about new thread.  */
 426 extern struct thread_info *add_thread_silent (ptid_t ptid);
 427
 428 /* Same as add_thread, and sets the private info.  */
 429 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 430                                                  struct private_thread_info *);
 431
 432 /* Delete an existing thread list entry.  */
 433 extern void delete_thread (struct thread_info *thread);
 434
 435 /* Delete an existing thread list entry, and be quiet about it.  Used
 436    after the process this thread having belonged to having already
 437    exited, for example.  */
 438 extern void delete_thread_silent (struct thread_info *thread);
 439
 440 /* Delete a step_resume_breakpoint from the thread database.  */
 441 extern void delete_step_resume_breakpoint (struct thread_info *);
 442
 443 /* Delete an exception_resume_breakpoint from the thread database.  */
 444 extern void delete_exception_resume_breakpoint (struct thread_info *);
 445
 446 /* Delete the single-step breakpoints of thread TP, if any.  */
 447 extern void delete_single_step_breakpoints (struct thread_info *tp);
 448
 449 /* Check if the thread has software single stepping breakpoints
 450    set.  */
 451 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 452
 453 /* Check whether the thread has software single stepping breakpoints
 454    set at PC.  */
 455 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 456                                                    const address_space *aspace,
 457                                                    CORE_ADDR addr);
 458
 459 /* Returns whether to show inferior-qualified thread IDs, or plain
 460    thread numbers.  Inferior-qualified IDs are shown whenever we have
 461    multiple inferiors, or the only inferior left has number > 1.  */
 462 extern int show_inferior_qualified_tids (void);
 463
 464 /* Return a string version of THR's thread ID.  If there are multiple
 465    inferiors, then this prints the inferior-qualifier form, otherwise
 466    it only prints the thread number.  The result is stored in a
 467    circular static buffer, NUMCELLS deep.  */
 468 const char *print_thread_id (struct thread_info *thr);
 469
 470 /* Boolean test for an already-known ptid.  */
 471 extern int in_thread_list (ptid_t ptid);
 472
 473 /* Boolean test for an already-known global thread id (GDB's homegrown
 474    global id, not the system's).  */
 475 extern int valid_global_thread_id (int global_id);
 476
 477 /* Search function to lookup a thread by 'pid'.  */
 478 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 479
 480 /* Search function to lookup a thread by 'ptid'.  Only searches in
 481    threads of INF.  */
 482 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 483
 484 /* Find thread by GDB global thread ID.  */
 485 struct thread_info *find_thread_global_id (int global_id);
 486
 487 /* Find thread by thread library specific handle in inferior INF.  */
 488 struct thread_info *find_thread_by_handle
 489   (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
 490
 491 /* Finds the first thread of the specified inferior.  */
 492 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 493
 494 /* Returns any thread of inferior INF, giving preference to the
 495    current thread.  */
 496 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 497
 498 /* Returns any non-exited thread of inferior INF, giving preference to
 499    the current thread, and to not executing threads.  */
 500 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 501
 502 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 503 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 504
 505 /* Iterator function to call a user-provided callback function
 506    once for each known thread.  */
 507 typedef int (*thread_callback_func) (struct thread_info *, void *);
 508 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 509
 510 /* Pull in the internals of the inferiors/threads ranges and
 511    iterators.  Must be done after struct thread_info is defined.  */
 512 #include "thread-iter.h"
 513
 514 /* Return a range that can be used to walk over all threads of all
 515    inferiors, with range-for.  Used like this:
 516
 517        for (thread_info *thr : all_threads ())
 518          { .... }
 519 */
 520 inline all_threads_range
 521 all_threads ()
 522 {
 523   return {};
 524 }
 525
 526 /* Likewise, but accept a filter PTID.  */
 527
 528 inline all_matching_threads_range
 529 all_threads (ptid_t filter_ptid)
 530 {
 531   return all_matching_threads_range (filter_ptid);
 532 }
 533
 534 /* Return a range that can be used to walk over all non-exited threads
 535    of all inferiors, with range-for.  FILTER_PTID can be used to
 536    filter out thread that don't match.  */
 537
 538 inline all_non_exited_threads_range
 539 all_non_exited_threads (ptid_t filter_ptid = minus_one_ptid)
 540 {
 541   return all_non_exited_threads_range (filter_ptid);
 542 }
 543
 544 /* Return a range that can be used to walk over all threads of all
 545    inferiors, with range-for, safely.  I.e., it is safe to delete the
 546    currently-iterated thread.  When combined with range-for, this
 547    allow convenient patterns like this:
 548
 549      for (thread_info *t : all_threads_safe ())
 550        if (some_condition ())
 551          delete f;
 552 */
 553
 554 inline all_threads_safe_range
 555 all_threads_safe ()
 556 {
 557   return all_threads_safe_range ();
 558 }
 559
 560 extern int thread_count (void);
 561
 562 /* Return true if we have any thread in any inferior.  */
 563 extern bool any_thread_p ();
 564
 565 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 566 extern void switch_to_thread (struct thread_info *thr);
 567
 568 /* Switch context to no thread selected.  */
 569 extern void switch_to_no_thread ();
 570
 571 /* Switch from one thread to another.  Does not read registers.  */
 572 extern void switch_to_thread_no_regs (struct thread_info *thread);
 573
 574 /* Marks or clears thread(s) PTID as resumed.  If PTID is
 575    MINUS_ONE_PTID, applies to all threads.  If ptid_is_pid(PTID) is
 576    true, applies to all threads of the process pointed at by PTID.  */
 577 extern void set_resumed (ptid_t ptid, int resumed);
 578
 579 /* Marks thread PTID is running, or stopped.
 580    If PTID is minus_one_ptid, marks all threads.  */
 581 extern void set_running (ptid_t ptid, int running);
 582
 583 /* Marks or clears thread(s) PTID as having been requested to stop.
 584    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 585    ptid_is_pid(PTID) is true, applies to all threads of the process
 586    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 587    observer is called with PTID as argument.  */
 588 extern void set_stop_requested (ptid_t ptid, int stop);
 589
 590 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 591    marks all threads.
 592
 593    Note that this is different from the running state.  See the
 594    description of state and executing fields of struct
 595    thread_info.  */
 596 extern void set_executing (ptid_t ptid, int executing);
 597
 598 /* True if any (known or unknown) thread is or may be executing.  */
 599 extern int threads_are_executing (void);
 600
 601 /* Merge the executing property of thread PTID over to its thread
 602    state property (frontend running/stopped view).
 603
 604    "not executing" -> "stopped"
 605    "executing"     -> "running"
 606    "exited"        -> "exited"
 607
 608    If PTID is minus_one_ptid, go over all threads.
 609
 610    Notifications are only emitted if the thread state did change.  */
 611 extern void finish_thread_state (ptid_t ptid);
 612
 613 /* Calls finish_thread_state on scope exit, unless release() is called
 614    to disengage.  */
 615 using scoped_finish_thread_state
 616   = FORWARD_SCOPE_EXIT (finish_thread_state);
 617
 618 /* Commands with a prefix of `thread'.  */
 619 extern struct cmd_list_element *thread_cmd_list;
 620
 621 extern void thread_command (const char *tidstr, int from_tty);
 622
 623 /* Print notices on thread events (attach, detach, etc.), set with
 624    `set print thread-events'.  */
 625 extern bool print_thread_events;
 626
 627 /* Prints the list of threads and their details on UIOUT.  If
 628    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 629    print threads whose ID is included in the list.  If PID is not -1,
 630    only print threads from the process PID.  Otherwise, threads from
 631    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 632    NULL and PID is not -1, then the thread is printed if it belongs to
 633    the specified process.  Otherwise, an error is raised.  */
 634 extern void print_thread_info (struct ui_out *uiout,
 635                                const char *requested_threads,
 636                                int pid);
 637
 638 /* Save/restore current inferior/thread/frame.  */
 639
 640 class scoped_restore_current_thread
 641 {
 642 public:
 643   scoped_restore_current_thread ();
 644   ~scoped_restore_current_thread ();
 645
 646   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 647
 648 private:
 649   /* Use the "class" keyword here, because of a clash with a "thread_info"
 650      function in the Darwin API.  */
 651   class thread_info *m_thread;
 652   inferior *m_inf;
 653   frame_id m_selected_frame_id;
 654   int m_selected_frame_level;
 655   bool m_was_stopped;
 656 };
 657
 658 /* Returns a pointer into the thread_info corresponding to
 659    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 660 extern struct thread_info* inferior_thread (void);
 661
 662 extern void update_thread_list (void);
 663
 664 /* Delete any thread the target says is no longer alive.  */
 665
 666 extern void prune_threads (void);
 667
 668 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 669    does not consult the target about whether the thread is alive right
 670    now.  */
 671 extern void delete_exited_threads (void);
 672
 673 /* Return true if PC is in the stepping range of THREAD.  */
 674
 675 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 676
 677 /* Enable storing stack temporaries for thread THR and disable and
 678    clear the stack temporaries on destruction.  Holds a strong
 679    reference to THR.  */
 680
 681 class enable_thread_stack_temporaries
 682 {
 683 public:
 684
 685   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 686     : m_thr (thr)
 687   {
 688     gdb_assert (m_thr != NULL);
 689
 690     m_thr->incref ();
 691
 692     m_thr->stack_temporaries_enabled = true;
 693     m_thr->stack_temporaries.clear ();
 694   }
 695
 696   ~enable_thread_stack_temporaries ()
 697   {
 698     m_thr->stack_temporaries_enabled = false;
 699     m_thr->stack_temporaries.clear ();
 700
 701     m_thr->decref ();
 702   }
 703
 704   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 705
 706 private:
 707
 708   struct thread_info *m_thr;
 709 };
 710
 711 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 712
 713 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 714
 715 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 716
 717 extern bool value_in_thread_stack_temporaries (struct value *,
 718                                                struct thread_info *thr);
 719
 720 /* Add TP to the end of its inferior's pending step-over chain.  */
 721
 722 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 723
 724 /* Remove TP from its inferior's pending step-over chain.  */
 725
 726 extern void thread_step_over_chain_remove (struct thread_info *tp);
 727
 728 /* Return the next thread in the step-over chain starting at TP.  NULL
 729    if TP is the last entry in the chain.  */
 730
 731 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 732
 733 /* Return true if TP is in the step-over chain.  */
 734
 735 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 736
 737 /* Cancel any ongoing execution command.  */
 738
 739 extern void thread_cancel_execution_command (struct thread_info *thr);
 740
 741 /* Check whether it makes sense to access a register of the current
 742    thread at this point.  If not, throw an error (e.g., the thread is
 743    executing).  */
 744 extern void validate_registers_access (void);
 745
 746 /* Check whether it makes sense to access a register of THREAD at this point.
 747    Returns true if registers may be accessed; false otherwise.  */
 748 extern bool can_access_registers_thread (struct thread_info *thread);
 749
 750 /* Returns whether to show which thread hit the breakpoint, received a
 751    signal, etc. and ended up causing a user-visible stop.  This is
 752    true iff we ever detected multiple threads.  */
 753 extern int show_thread_that_caused_stop (void);
 754
 755 /* Print the message for a thread or/and frame selected.  */
 756 extern void print_selected_thread_frame (struct ui_out *uiout,
 757                                          user_selected_what selection);
 758
 759 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 760    Selects thread THR.  TIDSTR is the original string the thread ID
 761    was parsed from.  This is used in the error message if THR is not
 762    alive anymore.  */
 763 extern void thread_select (const char *tidstr, class thread_info *thr);
 764
 765 #endif /* GDBTHREAD_H */