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 struct process_stratum_target;
  38
  39 /* Frontend view of the thread state.  Possible extensions: stepping,
  40    finishing, until(ling),...
  41
  42    NOTE: Since the thread state is not a boolean, most times, you do
  43    not want to check it with negation.  If you really want to check if
  44    the thread is stopped,
  45
  46     use (good):
  47
  48      if (tp->state == THREAD_STOPPED)
  49
  50     instead of (bad):
  51
  52      if (tp->state != THREAD_RUNNING)
  53
  54    The latter is also true for exited threads, most likely not what
  55    you want.  */
  56 enum thread_state
  57 {
  58   /* In the frontend's perpective, the thread is stopped.  */
  59   THREAD_STOPPED,
  60
  61   /* In the frontend's perpective, the thread is running.  */
  62   THREAD_RUNNING,
  63
  64   /* The thread is listed, but known to have exited.  We keep it
  65      listed (but not visible) until it's safe to delete it.  */
  66   THREAD_EXITED,
  67 };
  68
  69 /* STEP_OVER_ALL means step over all subroutine calls.
  70    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  71    STEP_OVER_NONE means don't step over any subroutine calls.  */
  72
  73 enum step_over_calls_kind
  74   {
  75     STEP_OVER_NONE,
  76     STEP_OVER_ALL,
  77     STEP_OVER_UNDEBUGGABLE
  78   };
  79
  80 /* Inferior thread specific part of `struct infcall_control_state'.
  81
  82    Inferior process counterpart is `struct inferior_control_state'.  */
  83
  84 struct thread_control_state
  85 {
  86   /* User/external stepping state.  */
  87
  88   /* Step-resume or longjmp-resume breakpoint.  */
  89   struct breakpoint *step_resume_breakpoint = nullptr;
  90
  91   /* Exception-resume breakpoint.  */
  92   struct breakpoint *exception_resume_breakpoint = nullptr;
  93
  94   /* Breakpoints used for software single stepping.  Plural, because
  95      it may have multiple locations.  E.g., if stepping over a
  96      conditional branch instruction we can't decode the condition for,
  97      we'll need to put a breakpoint at the branch destination, and
  98      another at the instruction after the branch.  */
  99   struct breakpoint *single_step_breakpoints = nullptr;
 100
 101   /* Range to single step within.
 102
 103      If this is nonzero, respond to a single-step signal by continuing
 104      to step if the pc is in this range.
 105
 106      If step_range_start and step_range_end are both 1, it means to
 107      step for a single instruction (FIXME: it might clean up
 108      wait_for_inferior in a minor way if this were changed to the
 109      address of the instruction and that address plus one.  But maybe
 110      not).  */
 111   CORE_ADDR step_range_start = 0;       /* Inclusive */
 112   CORE_ADDR step_range_end = 0;         /* Exclusive */
 113
 114   /* Function the thread was in as of last it started stepping.  */
 115   struct symbol *step_start_function = nullptr;
 116
 117   /* If GDB issues a target step request, and this is nonzero, the
 118      target should single-step this thread once, and then continue
 119      single-stepping it without GDB core involvement as long as the
 120      thread stops in the step range above.  If this is zero, the
 121      target should ignore the step range, and only issue one single
 122      step.  */
 123   int may_range_step = 0;
 124
 125   /* Stack frame address as of when stepping command was issued.
 126      This is how we know when we step into a subroutine call, and how
 127      to set the frame for the breakpoint used to step out.  */
 128   struct frame_id step_frame_id {};
 129
 130   /* Similarly, the frame ID of the underlying stack frame (skipping
 131      any inlined frames).  */
 132   struct frame_id step_stack_frame_id {};
 133
 134   /* Nonzero if we are presently stepping over a breakpoint.
 135
 136      If we hit a breakpoint or watchpoint, and then continue, we need
 137      to single step the current thread with breakpoints disabled, to
 138      avoid hitting the same breakpoint or watchpoint again.  And we
 139      should step just a single thread and keep other threads stopped,
 140      so that other threads don't miss breakpoints while they are
 141      removed.
 142
 143      So, this variable simultaneously means that we need to single
 144      step the current thread, keep other threads stopped, and that
 145      breakpoints should be removed while we step.
 146
 147      This variable is set either:
 148      - in proceed, when we resume inferior on user's explicit request
 149      - in keep_going, if handle_inferior_event decides we need to
 150      step over breakpoint.
 151
 152      The variable is cleared in normal_stop.  The proceed calls
 153      wait_for_inferior, which calls handle_inferior_event in a loop,
 154      and until wait_for_inferior exits, this variable is changed only
 155      by keep_going.  */
 156   int trap_expected = 0;
 157
 158   /* Nonzero if the thread is being proceeded for a "finish" command
 159      or a similar situation when return value should be printed.  */
 160   int proceed_to_finish = 0;
 161
 162   /* Nonzero if the thread is being proceeded for an inferior function
 163      call.  */
 164   int in_infcall = 0;
 165
 166   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 167
 168   /* Nonzero if stopped due to a step command.  */
 169   int stop_step = 0;
 170
 171   /* Chain containing status of breakpoint(s) the thread stopped
 172      at.  */
 173   bpstat stop_bpstat = nullptr;
 174
 175   /* Whether the command that started the thread was a stepping
 176      command.  This is used to decide whether "set scheduler-locking
 177      step" behaves like "on" or "off".  */
 178   int stepping_command = 0;
 179 };
 180
 181 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 182
 183 struct thread_suspend_state
 184 {
 185   /* Last signal that the inferior received (why it stopped).  When
 186      the thread is resumed, this signal is delivered.  Note: the
 187      target should not check whether the signal is in pass state,
 188      because the signal may have been explicitly passed with the
 189      "signal" command, which overrides "handle nopass".  If the signal
 190      should be suppressed, the core will take care of clearing this
 191      before the target is resumed.  */
 192   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 193
 194   /* The reason the thread last stopped, if we need to track it
 195      (breakpoint, watchpoint, etc.)  */
 196   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 197
 198   /* The waitstatus for this thread's last event.  */
 199   struct target_waitstatus waitstatus {};
 200   /* If true WAITSTATUS hasn't been handled yet.  */
 201   int waitstatus_pending_p = 0;
 202
 203   /* Record the pc of the thread the last time it stopped.  (This is
 204      not the current thread's PC as that may have changed since the
 205      last stop, e.g., "return" command, or "p $pc = 0xf000").
 206
 207      - If the thread's PC has not changed since the thread last
 208        stopped, then proceed skips a breakpoint at the current PC,
 209        otherwise we let the thread run into the breakpoint.
 210
 211      - If the thread has an unprocessed event pending, as indicated by
 212        waitstatus_pending_p, this is used in coordination with
 213        stop_reason: if the thread's PC has changed since the thread
 214        last stopped, a pending breakpoint waitstatus is discarded.
 215
 216      - If the thread is running, this is set to -1, to avoid leaving
 217        it with a stale value, to make it easier to catch bugs.  */
 218   CORE_ADDR stop_pc = 0;
 219 };
 220
 221 /* Base class for target-specific thread data.  */
 222 struct private_thread_info
 223 {
 224   virtual ~private_thread_info () = 0;
 225 };
 226
 227 /* Threads are intrusively refcounted objects.  Being the
 228    user-selected thread is normally considered an implicit strong
 229    reference and is thus not accounted in the refcount, unlike
 230    inferior objects.  This is necessary, because there's no "current
 231    thread" pointer.  Instead the current thread is inferred from the
 232    inferior_ptid global.  However, when GDB needs to remember the
 233    selected thread to later restore it, GDB bumps the thread object's
 234    refcount, to prevent something deleting the thread object before
 235    reverting back (e.g., due to a "kill" command).  If the thread
 236    meanwhile exits before being re-selected, then the thread object is
 237    left listed in the thread list, but marked with state
 238    THREAD_EXITED.  (See scoped_restore_current_thread and
 239    delete_thread).  All other thread references are considered weak
 240    references.  Placing a thread in the thread list is an implicit
 241    strong reference, and is thus not accounted for in the thread's
 242    refcount.  */
 243
 244 class thread_info : public refcounted_object
 245 {
 246 public:
 247   explicit thread_info (inferior *inf, ptid_t ptid);
 248   ~thread_info ();
 249
 250   bool deletable () const;
 251
 252   /* Mark this thread as running and notify observers.  */
 253   void set_running (bool running);
 254
 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   bool executing = false;
 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 (process_stratum_target *targ,
 423                                        ptid_t ptid);
 424
 425 /* Same as add_thread, but does not print a message about new
 426    thread.  */
 427 extern struct thread_info *add_thread_silent (process_stratum_target *targ,
 428                                               ptid_t ptid);
 429
 430 /* Same as add_thread, and sets the private info.  */
 431 extern struct thread_info *add_thread_with_info (process_stratum_target *targ,
 432                                                  ptid_t ptid,
 433                                                  private_thread_info *);
 434
 435 /* Delete an existing thread, removing the entry from its inferior's thread
 436    map.  */
 437 extern void delete_thread (struct thread_info *thread);
 438
 439 /* Like the above, but don't remove the entry from the inferior thread map.  */
 440 extern void delete_thread_noremove(struct thread_info *thread);
 441
 442 /* Delete an existing thread list entry, and be quiet about it.  Used
 443    after the process this thread having belonged to having already
 444    exited, for example.  */
 445 extern void delete_thread_silent (struct thread_info *thread);
 446
 447 /* Like the above, but don't remove the entry from the inferior thread map.  */
 448 extern void delete_thread_silent_noremove (thread_info *thread);
 449
 450 /* Delete a step_resume_breakpoint from the thread database.  */
 451 extern void delete_step_resume_breakpoint (struct thread_info *);
 452
 453 /* Delete an exception_resume_breakpoint from the thread database.  */
 454 extern void delete_exception_resume_breakpoint (struct thread_info *);
 455
 456 /* Delete the single-step breakpoints of thread TP, if any.  */
 457 extern void delete_single_step_breakpoints (struct thread_info *tp);
 458
 459 /* Check if the thread has software single stepping breakpoints
 460    set.  */
 461 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 462
 463 /* Check whether the thread has software single stepping breakpoints
 464    set at PC.  */
 465 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 466                                                    const address_space *aspace,
 467                                                    CORE_ADDR addr);
 468
 469 /* Returns whether to show inferior-qualified thread IDs, or plain
 470    thread numbers.  Inferior-qualified IDs are shown whenever we have
 471    multiple inferiors, or the only inferior left has number > 1.  */
 472 extern int show_inferior_qualified_tids (void);
 473
 474 /* Return a string version of THR's thread ID.  If there are multiple
 475    inferiors, then this prints the inferior-qualifier form, otherwise
 476    it only prints the thread number.  The result is stored in a
 477    circular static buffer, NUMCELLS deep.  */
 478 const char *print_thread_id (struct thread_info *thr);
 479
 480 /* Boolean test for an already-known ptid.  */
 481 extern bool in_thread_list (process_stratum_target *targ, ptid_t ptid);
 482
 483 /* Boolean test for an already-known global thread id (GDB's homegrown
 484    global id, not the system's).  */
 485 extern int valid_global_thread_id (int global_id);
 486
 487 /* Find thread PTID of inferior INF.  */
 488 extern thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 489
 490 /* Search function to lookup a thread by 'pid'.  */
 491 extern struct thread_info *find_thread_ptid (process_stratum_target *targ,
 492                                              ptid_t ptid);
 493
 494 /* Search function to lookup a thread by 'ptid'.  Only searches in
 495    threads of INF.  */
 496 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 497
 498 /* Find thread by GDB global thread ID.  */
 499 struct thread_info *find_thread_global_id (int global_id);
 500
 501 /* Find thread by thread library specific handle in inferior INF.  */
 502 struct thread_info *find_thread_by_handle
 503   (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
 504
 505 /* Finds the first thread of the specified inferior.  */
 506 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 507
 508 /* Returns any thread of inferior INF, giving preference to the
 509    current thread.  */
 510 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 511
 512 /* Returns any non-exited thread of inferior INF, giving preference to
 513    the current thread, and to not executing threads.  */
 514 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 515
 516 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 517 void thread_change_ptid (process_stratum_target *targ,
 518                          ptid_t old_ptid, ptid_t new_ptid);
 519
 520 /* Iterator function to call a user-provided callback function
 521    once for each known thread.  */
 522 typedef int (*thread_callback_func) (struct thread_info *, void *);
 523 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 524
 525 /* Pull in the internals of the inferiors/threads ranges and
 526    iterators.  Must be done after struct thread_info is defined.  */
 527 #include "thread-iter.h"
 528
 529 /* Return a range that can be used to walk over threads, with
 530    range-for.
 531
 532    Used like this, it walks over all threads of all inferiors of all
 533    targets:
 534
 535        for (thread_info *thr : all_threads ())
 536          { .... }
 537
 538    FILTER_PTID can be used to filter out threads that don't match.
 539    FILTER_PTID can be:
 540
 541    - minus_one_ptid, meaning walk all threads of all inferiors of
 542      PROC_TARGET.  If PROC_TARGET is NULL, then of all targets.
 543
 544    - A process ptid, in which case walk all threads of the specified
 545      process.  PROC_TARGET must be non-NULL in this case.
 546
 547    - A thread ptid, in which case walk that thread only.  PROC_TARGET
 548      must be non-NULL in this case.
 549 */
 550
 551 inline all_matching_threads_range
 552 all_threads (process_stratum_target *proc_target = nullptr,
 553              ptid_t filter_ptid = minus_one_ptid)
 554 {
 555   return all_matching_threads_range (proc_target, filter_ptid);
 556 }
 557
 558 /* Return a range that can be used to walk over all non-exited threads
 559    of all inferiors, with range-for.  Arguments are like all_threads
 560    above.  */
 561
 562 inline all_non_exited_threads_range
 563 all_non_exited_threads (process_stratum_target *proc_target = nullptr,
 564                         ptid_t filter_ptid = minus_one_ptid)
 565 {
 566   return all_non_exited_threads_range (proc_target, filter_ptid);
 567 }
 568
 569 /* Return a range that can be used to walk over all threads of all
 570    inferiors, with range-for, safely.  I.e., it is safe to delete the
 571    currently-iterated thread.  When combined with range-for, this
 572    allow convenient patterns like this:
 573
 574      for (thread_info *t : all_threads_safe ())
 575        if (some_condition ())
 576          delete f;
 577 */
 578
 579 inline all_threads_safe_range
 580 all_threads_safe ()
 581 {
 582   return {};
 583 }
 584
 585 extern int thread_count (process_stratum_target *proc_target);
 586
 587 /* Return true if we have any thread in any inferior.  */
 588 extern bool any_thread_p ();
 589
 590 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 591 extern void switch_to_thread (struct thread_info *thr);
 592
 593 /* Switch context to no thread selected.  */
 594 extern void switch_to_no_thread ();
 595
 596 /* Switch from one thread to another.  Does not read registers.  */
 597 extern void switch_to_thread_no_regs (struct thread_info *thread);
 598
 599 /* Marks or clears thread(s) PTID of TARG as resumed.  If PTID is
 600    MINUS_ONE_PTID, applies to all threads of TARG.  If
 601    ptid_is_pid(PTID) is true, applies to all threads of the process
 602    pointed at by {TARG,PTID}.  */
 603 extern void set_resumed (process_stratum_target *targ,
 604                          ptid_t ptid, bool resumed);
 605
 606 /* Marks thread PTID of TARG as running, or as stopped.  If PTID is
 607    minus_one_ptid, marks all threads of TARG.  */
 608 extern void set_running (process_stratum_target *targ,
 609                          ptid_t ptid, bool running);
 610
 611 /* Marks or clears thread(s) PTID of TARG as having been requested to
 612    stop.  If PTID is MINUS_ONE_PTID, applies to all threads of TARG.
 613    If ptid_is_pid(PTID) is true, applies to all threads of the process
 614    pointed at by {TARG, PTID}.  If STOP, then the
 615    THREAD_STOP_REQUESTED observer is called with PTID as argument.  */
 616 extern void set_stop_requested (process_stratum_target *targ,
 617                                 ptid_t ptid, bool stop);
 618
 619 /* Marks thread PTID of TARG as executing, or not.  If PTID is
 620    minus_one_ptid, marks all threads of TARG.
 621
 622    Note that this is different from the running state.  See the
 623    description of state and executing fields of struct
 624    thread_info.  */
 625 extern void set_executing (process_stratum_target *targ,
 626                            ptid_t ptid, bool executing);
 627
 628 /* True if any (known or unknown) thread of TARG is or may be
 629    executing.  */
 630 extern bool threads_are_executing (process_stratum_target *targ);
 631
 632 /* Merge the executing property of thread PTID of TARG over to its
 633    thread state property (frontend running/stopped view).
 634
 635    "not executing" -> "stopped"
 636    "executing"     -> "running"
 637    "exited"        -> "exited"
 638
 639    If PTID is minus_one_ptid, go over all threads of TARG.
 640
 641    Notifications are only emitted if the thread state did change.  */
 642 extern void finish_thread_state (process_stratum_target *targ, ptid_t ptid);
 643
 644 /* Calls finish_thread_state on scope exit, unless release() is called
 645    to disengage.  */
 646 using scoped_finish_thread_state
 647   = FORWARD_SCOPE_EXIT (finish_thread_state);
 648
 649 /* Commands with a prefix of `thread'.  */
 650 extern struct cmd_list_element *thread_cmd_list;
 651
 652 extern void thread_command (const char *tidstr, int from_tty);
 653
 654 /* Print notices on thread events (attach, detach, etc.), set with
 655    `set print thread-events'.  */
 656 extern bool print_thread_events;
 657
 658 /* Prints the list of threads and their details on UIOUT.  If
 659    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 660    print threads whose ID is included in the list.  If PID is not -1,
 661    only print threads from the process PID.  Otherwise, threads from
 662    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 663    NULL and PID is not -1, then the thread is printed if it belongs to
 664    the specified process.  Otherwise, an error is raised.  */
 665 extern void print_thread_info (struct ui_out *uiout,
 666                                const char *requested_threads,
 667                                int pid);
 668
 669 /* Save/restore current inferior/thread/frame.  */
 670
 671 class scoped_restore_current_thread
 672 {
 673 public:
 674   scoped_restore_current_thread ();
 675   ~scoped_restore_current_thread ();
 676
 677   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 678
 679   /* Cancel restoring on scope exit.  */
 680   void dont_restore () { m_dont_restore = true; }
 681
 682 private:
 683   void restore ();
 684
 685   bool m_dont_restore = false;
 686   /* Use the "class" keyword here, because of a clash with a "thread_info"
 687      function in the Darwin API.  */
 688   class thread_info *m_thread;
 689   inferior *m_inf;
 690   frame_id m_selected_frame_id;
 691   int m_selected_frame_level;
 692   bool m_was_stopped;
 693 };
 694
 695 /* Returns a pointer into the thread_info corresponding to
 696    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 697 extern struct thread_info* inferior_thread (void);
 698
 699 extern void update_thread_list (void);
 700
 701 /* Delete any thread the target says is no longer alive.  */
 702
 703 extern void prune_threads (void);
 704
 705 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 706    does not consult the target about whether the thread is alive right
 707    now.  */
 708 extern void delete_exited_threads (void);
 709
 710 /* Return true if PC is in the stepping range of THREAD.  */
 711
 712 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 713
 714 /* Enable storing stack temporaries for thread THR and disable and
 715    clear the stack temporaries on destruction.  Holds a strong
 716    reference to THR.  */
 717
 718 class enable_thread_stack_temporaries
 719 {
 720 public:
 721
 722   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 723     : m_thr (thr)
 724   {
 725     gdb_assert (m_thr != NULL);
 726
 727     m_thr->incref ();
 728
 729     m_thr->stack_temporaries_enabled = true;
 730     m_thr->stack_temporaries.clear ();
 731   }
 732
 733   ~enable_thread_stack_temporaries ()
 734   {
 735     m_thr->stack_temporaries_enabled = false;
 736     m_thr->stack_temporaries.clear ();
 737
 738     m_thr->decref ();
 739   }
 740
 741   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 742
 743 private:
 744
 745   struct thread_info *m_thr;
 746 };
 747
 748 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 749
 750 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 751
 752 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 753
 754 extern bool value_in_thread_stack_temporaries (struct value *,
 755                                                struct thread_info *thr);
 756
 757 /* Add TP to the end of its inferior's pending step-over chain.  */
 758
 759 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 760
 761 /* Remove TP from its inferior's pending step-over chain.  */
 762
 763 extern void thread_step_over_chain_remove (struct thread_info *tp);
 764
 765 /* Return the next thread in the step-over chain starting at TP.  NULL
 766    if TP is the last entry in the chain.  */
 767
 768 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 769
 770 /* Return true if TP is in the step-over chain.  */
 771
 772 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 773
 774 /* Cancel any ongoing execution command.  */
 775
 776 extern void thread_cancel_execution_command (struct thread_info *thr);
 777
 778 /* Check whether it makes sense to access a register of the current
 779    thread at this point.  If not, throw an error (e.g., the thread is
 780    executing).  */
 781 extern void validate_registers_access (void);
 782
 783 /* Check whether it makes sense to access a register of THREAD at this point.
 784    Returns true if registers may be accessed; false otherwise.  */
 785 extern bool can_access_registers_thread (struct thread_info *thread);
 786
 787 /* Returns whether to show which thread hit the breakpoint, received a
 788    signal, etc. and ended up causing a user-visible stop.  This is
 789    true iff we ever detected multiple threads.  */
 790 extern int show_thread_that_caused_stop (void);
 791
 792 /* Print the message for a thread or/and frame selected.  */
 793 extern void print_selected_thread_frame (struct ui_out *uiout,
 794                                          user_selected_what selection);
 795
 796 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 797    Selects thread THR.  TIDSTR is the original string the thread ID
 798    was parsed from.  This is used in the error message if THR is not
 799    alive anymore.  */
 800 extern void thread_select (const char *tidstr, class thread_info *thr);
 801
 802 #endif /* GDBTHREAD_H */