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 #include "displaced-stepping.h"
  36
  37 struct inferior;
  38 struct process_stratum_target;
  39
  40 /* Frontend view of the thread state.  Possible extensions: stepping,
  41    finishing, until(ling),...
  42
  43    NOTE: Since the thread state is not a boolean, most times, you do
  44    not want to check it with negation.  If you really want to check if
  45    the thread is stopped,
  46
  47     use (good):
  48
  49      if (tp->state == THREAD_STOPPED)
  50
  51     instead of (bad):
  52
  53      if (tp->state != THREAD_RUNNING)
  54
  55    The latter is also true for exited threads, most likely not what
  56    you want.  */
  57 enum thread_state
  58 {
  59   /* In the frontend's perpective, the thread is stopped.  */
  60   THREAD_STOPPED,
  61
  62   /* In the frontend's perpective, the thread is running.  */
  63   THREAD_RUNNING,
  64
  65   /* The thread is listed, but known to have exited.  We keep it
  66      listed (but not visible) until it's safe to delete it.  */
  67   THREAD_EXITED,
  68 };
  69
  70 /* STEP_OVER_ALL means step over all subroutine calls.
  71    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  72    STEP_OVER_NONE means don't step over any subroutine calls.  */
  73
  74 enum step_over_calls_kind
  75   {
  76     STEP_OVER_NONE,
  77     STEP_OVER_ALL,
  78     STEP_OVER_UNDEBUGGABLE
  79   };
  80
  81 /* Inferior thread specific part of `struct infcall_control_state'.
  82
  83    Inferior process counterpart is `struct inferior_control_state'.  */
  84
  85 struct thread_control_state
  86 {
  87   /* User/external stepping state.  */
  88
  89   /* Step-resume or longjmp-resume breakpoint.  */
  90   struct breakpoint *step_resume_breakpoint = nullptr;
  91
  92   /* Exception-resume breakpoint.  */
  93   struct breakpoint *exception_resume_breakpoint = nullptr;
  94
  95   /* Breakpoints used for software single stepping.  Plural, because
  96      it may have multiple locations.  E.g., if stepping over a
  97      conditional branch instruction we can't decode the condition for,
  98      we'll need to put a breakpoint at the branch destination, and
  99      another at the instruction after the branch.  */
 100   struct breakpoint *single_step_breakpoints = nullptr;
 101
 102   /* Range to single step within.
 103
 104      If this is nonzero, respond to a single-step signal by continuing
 105      to step if the pc is in this range.
 106
 107      If step_range_start and step_range_end are both 1, it means to
 108      step for a single instruction (FIXME: it might clean up
 109      wait_for_inferior in a minor way if this were changed to the
 110      address of the instruction and that address plus one.  But maybe
 111      not).  */
 112   CORE_ADDR step_range_start = 0;       /* Inclusive */
 113   CORE_ADDR step_range_end = 0;         /* Exclusive */
 114
 115   /* Function the thread was in as of last it started stepping.  */
 116   struct symbol *step_start_function = nullptr;
 117
 118   /* If GDB issues a target step request, and this is nonzero, the
 119      target should single-step this thread once, and then continue
 120      single-stepping it without GDB core involvement as long as the
 121      thread stops in the step range above.  If this is zero, the
 122      target should ignore the step range, and only issue one single
 123      step.  */
 124   int may_range_step = 0;
 125
 126   /* Stack frame address as of when stepping command was issued.
 127      This is how we know when we step into a subroutine call, and how
 128      to set the frame for the breakpoint used to step out.  */
 129   struct frame_id step_frame_id {};
 130
 131   /* Similarly, the frame ID of the underlying stack frame (skipping
 132      any inlined frames).  */
 133   struct frame_id step_stack_frame_id {};
 134
 135   /* Nonzero if we are presently stepping over a breakpoint.
 136
 137      If we hit a breakpoint or watchpoint, and then continue, we need
 138      to single step the current thread with breakpoints disabled, to
 139      avoid hitting the same breakpoint or watchpoint again.  And we
 140      should step just a single thread and keep other threads stopped,
 141      so that other threads don't miss breakpoints while they are
 142      removed.
 143
 144      So, this variable simultaneously means that we need to single
 145      step the current thread, keep other threads stopped, and that
 146      breakpoints should be removed while we step.
 147
 148      This variable is set either:
 149      - in proceed, when we resume inferior on user's explicit request
 150      - in keep_going, if handle_inferior_event decides we need to
 151      step over breakpoint.
 152
 153      The variable is cleared in normal_stop.  The proceed calls
 154      wait_for_inferior, which calls handle_inferior_event in a loop,
 155      and until wait_for_inferior exits, this variable is changed only
 156      by keep_going.  */
 157   int trap_expected = 0;
 158
 159   /* Nonzero if the thread is being proceeded for a "finish" command
 160      or a similar situation when return value should be printed.  */
 161   int proceed_to_finish = 0;
 162
 163   /* Nonzero if the thread is being proceeded for an inferior function
 164      call.  */
 165   int in_infcall = 0;
 166
 167   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 168
 169   /* Nonzero if stopped due to a step command.  */
 170   int stop_step = 0;
 171
 172   /* Chain containing status of breakpoint(s) the thread stopped
 173      at.  */
 174   bpstat stop_bpstat = nullptr;
 175
 176   /* Whether the command that started the thread was a stepping
 177      command.  This is used to decide whether "set scheduler-locking
 178      step" behaves like "on" or "off".  */
 179   int stepping_command = 0;
 180 };
 181
 182 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 183
 184 struct thread_suspend_state
 185 {
 186   /* Last signal that the inferior received (why it stopped).  When
 187      the thread is resumed, this signal is delivered.  Note: the
 188      target should not check whether the signal is in pass state,
 189      because the signal may have been explicitly passed with the
 190      "signal" command, which overrides "handle nopass".  If the signal
 191      should be suppressed, the core will take care of clearing this
 192      before the target is resumed.  */
 193   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 194
 195   /* The reason the thread last stopped, if we need to track it
 196      (breakpoint, watchpoint, etc.)  */
 197   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 198
 199   /* The waitstatus for this thread's last event.  */
 200   struct target_waitstatus waitstatus {};
 201   /* If true WAITSTATUS hasn't been handled yet.  */
 202   int waitstatus_pending_p = 0;
 203
 204   /* Record the pc of the thread the last time it stopped.  (This is
 205      not the current thread's PC as that may have changed since the
 206      last stop, e.g., "return" command, or "p $pc = 0xf000").
 207
 208      - If the thread's PC has not changed since the thread last
 209        stopped, then proceed skips a breakpoint at the current PC,
 210        otherwise we let the thread run into the breakpoint.
 211
 212      - If the thread has an unprocessed event pending, as indicated by
 213        waitstatus_pending_p, this is used in coordination with
 214        stop_reason: if the thread's PC has changed since the thread
 215        last stopped, a pending breakpoint waitstatus is discarded.
 216
 217      - If the thread is running, this is set to -1, to avoid leaving
 218        it with a stale value, to make it easier to catch bugs.  */
 219   CORE_ADDR stop_pc = 0;
 220 };
 221
 222 /* Base class for target-specific thread data.  */
 223 struct private_thread_info
 224 {
 225   virtual ~private_thread_info () = 0;
 226 };
 227
 228 /* Threads are intrusively refcounted objects.  Being the
 229    user-selected thread is normally considered an implicit strong
 230    reference and is thus not accounted in the refcount, unlike
 231    inferior objects.  This is necessary, because there's no "current
 232    thread" pointer.  Instead the current thread is inferred from the
 233    inferior_ptid global.  However, when GDB needs to remember the
 234    selected thread to later restore it, GDB bumps the thread object's
 235    refcount, to prevent something deleting the thread object before
 236    reverting back (e.g., due to a "kill" command).  If the thread
 237    meanwhile exits before being re-selected, then the thread object is
 238    left listed in the thread list, but marked with state
 239    THREAD_EXITED.  (See scoped_restore_current_thread and
 240    delete_thread).  All other thread references are considered weak
 241    references.  Placing a thread in the thread list is an implicit
 242    strong reference, and is thus not accounted for in the thread's
 243    refcount.  */
 244
 245 class thread_info : public refcounted_object
 246 {
 247 public:
 248   explicit thread_info (inferior *inf, ptid_t ptid);
 249   ~thread_info ();
 250
 251   bool deletable () const;
 252
 253   /* Mark this thread as running and notify observers.  */
 254   void set_running (bool running);
 255
 256   struct regcache *regcache ();
 257   struct gdbarch *arch ();
 258
 259   struct thread_info *next = NULL;
 260   ptid_t ptid;                  /* "Actual process id";
 261                                     In fact, this may be overloaded with
 262                                     kernel thread id, etc.  */
 263
 264   /* Each thread has two GDB IDs.
 265
 266      a) The thread ID (Id).  This consists of the pair of:
 267
 268         - the number of the thread's inferior and,
 269
 270         - the thread's thread number in its inferior, aka, the
 271           per-inferior thread number.  This number is unique in the
 272           inferior but not unique between inferiors.
 273
 274      b) The global ID (GId).  This is a a single integer unique
 275         between all inferiors.
 276
 277      E.g.:
 278
 279       (gdb) info threads -gid
 280         Id    GId   Target Id   Frame
 281       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 282         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 283         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 284         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 285         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 286         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 287
 288      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 289      thread has its own unique global ID.  */
 290
 291   /* The thread's global GDB thread number.  This is exposed to MI,
 292      Python/Scheme, visible with "info threads -gid", and is also what
 293      the $_gthread convenience variable is bound to.  */
 294   int global_num;
 295
 296   /* The per-inferior thread number.  This is unique in the inferior
 297      the thread belongs to, but not unique between inferiors.  This is
 298      what the $_thread convenience variable is bound to.  */
 299   int per_inf_num;
 300
 301   /* The inferior this thread belongs to.  */
 302   struct inferior *inf;
 303
 304   /* The name of the thread, as specified by the user.  This is NULL
 305      if the thread does not have a user-given name.  */
 306   char *name = NULL;
 307
 308   /* True means the thread is executing.  Note: this is different
 309      from saying that there is an active target and we are stopped at
 310      a breakpoint, for instance.  This is a real indicator whether the
 311      thread is off and running.  */
 312   bool executing = false;
 313
 314   /* True if this thread is resumed from infrun's perspective.
 315      Note that a thread can be marked both as not-executing and
 316      resumed at the same time.  This happens if we try to resume a
 317      thread that has a wait status pending.  We shouldn't let the
 318      thread really run until that wait status has been processed, but
 319      we should not process that wait status if we didn't try to let
 320      the thread run.  */
 321   bool resumed = false;
 322
 323   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 324      THREAD_STOPPED states are different from EXECUTING.  When the
 325      thread is stopped internally while handling an internal event,
 326      like a software single-step breakpoint, EXECUTING will be false,
 327      but STATE will still be THREAD_RUNNING.  */
 328   enum thread_state state = THREAD_STOPPED;
 329
 330   /* State of GDB control of inferior thread execution.
 331      See `struct thread_control_state'.  */
 332   thread_control_state control;
 333
 334   /* State of inferior thread to restore after GDB is done with an inferior
 335      call.  See `struct thread_suspend_state'.  */
 336   thread_suspend_state suspend;
 337
 338   int current_line = 0;
 339   struct symtab *current_symtab = NULL;
 340
 341   /* Internal stepping state.  */
 342
 343   /* Record the pc of the thread the last time it was resumed.  (It
 344      can't be done on stop as the PC may change since the last stop,
 345      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 346      by proceed and keep_going, and among other things, it's used in
 347      adjust_pc_after_break to distinguish a hardware single-step
 348      SIGTRAP from a breakpoint SIGTRAP.  */
 349   CORE_ADDR prev_pc = 0;
 350
 351   /* Did we set the thread stepping a breakpoint instruction?  This is
 352      used in conjunction with PREV_PC to decide whether to adjust the
 353      PC.  */
 354   int stepped_breakpoint = 0;
 355
 356   /* Should we step over breakpoint next time keep_going is called?  */
 357   int stepping_over_breakpoint = 0;
 358
 359   /* Should we step over a watchpoint next time keep_going is called?
 360      This is needed on targets with non-continuable, non-steppable
 361      watchpoints.  */
 362   int stepping_over_watchpoint = 0;
 363
 364   /* Set to TRUE if we should finish single-stepping over a breakpoint
 365      after hitting the current step-resume breakpoint.  The context here
 366      is that GDB is to do `next' or `step' while signal arrives.
 367      When stepping over a breakpoint and signal arrives, GDB will attempt
 368      to skip signal handler, so it inserts a step_resume_breakpoint at the
 369      signal return address, and resume inferior.
 370      step_after_step_resume_breakpoint is set to TRUE at this moment in
 371      order to keep GDB in mind that there is still a breakpoint to step over
 372      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 373   int step_after_step_resume_breakpoint = 0;
 374
 375   /* Pointer to the state machine manager object that handles what is
 376      left to do for the thread's execution command after the target
 377      stops.  Several execution commands use it.  */
 378   struct thread_fsm *thread_fsm = NULL;
 379
 380   /* This is used to remember when a fork or vfork event was caught by
 381      a catchpoint, and thus the event is to be followed at the next
 382      resume of the thread, and not immediately.  */
 383   struct target_waitstatus pending_follow;
 384
 385   /* True if this thread has been explicitly requested to stop.  */
 386   int stop_requested = 0;
 387
 388   /* The initiating frame of a nexting operation, used for deciding
 389      which exceptions to intercept.  If it is null_frame_id no
 390      bp_longjmp or bp_exception but longjmp has been caught just for
 391      bp_longjmp_call_dummy.  */
 392   struct frame_id initiating_frame = null_frame_id;
 393
 394   /* Private data used by the target vector implementation.  */
 395   std::unique_ptr<private_thread_info> priv;
 396
 397   /* Branch trace information for this thread.  */
 398   struct btrace_thread_info btrace {};
 399
 400   /* Flag which indicates that the stack temporaries should be stored while
 401      evaluating expressions.  */
 402   bool stack_temporaries_enabled = false;
 403
 404   /* Values that are stored as temporaries on stack while evaluating
 405      expressions.  */
 406   std::vector<struct value *> stack_temporaries;
 407
 408   /* Step-over chain.  A thread is in the step-over queue if these are
 409      non-NULL.  If only a single thread is in the chain, then these
 410      fields point to self.  */
 411   struct thread_info *step_over_prev = NULL;
 412   struct thread_info *step_over_next = NULL;
 413
 414   displaced_step_thread_state displaced_step_state;
 415 };
 416
 417 /* A gdb::ref_ptr pointer to a thread_info.  */
 418
 419 using thread_info_ref
 420   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 421
 422 /* Create an empty thread list, or empty the existing one.  */
 423 extern void init_thread_list (void);
 424
 425 /* Add a thread to the thread list, print a message
 426    that a new thread is found, and return the pointer to
 427    the new thread.  Caller my use this pointer to
 428    initialize the private thread data.  */
 429 extern struct thread_info *add_thread (process_stratum_target *targ,
 430                                        ptid_t ptid);
 431
 432 /* Same as add_thread, but does not print a message about new
 433    thread.  */
 434 extern struct thread_info *add_thread_silent (process_stratum_target *targ,
 435                                               ptid_t ptid);
 436
 437 /* Same as add_thread, and sets the private info.  */
 438 extern struct thread_info *add_thread_with_info (process_stratum_target *targ,
 439                                                  ptid_t ptid,
 440                                                  private_thread_info *);
 441
 442 /* Delete an existing thread list entry.  */
 443 extern void delete_thread (struct thread_info *thread);
 444
 445 /* Delete an existing thread list entry, and be quiet about it.  Used
 446    after the process this thread having belonged to having already
 447    exited, for example.  */
 448 extern void delete_thread_silent (struct 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 the global pending step-over chain.  */
 758
 759 extern void global_thread_step_over_chain_enqueue (struct thread_info *tp);
 760
 761 /* Remove TP from step-over chain LIST_P.  */
 762
 763 extern void thread_step_over_chain_remove (thread_info **list_p,
 764                                            thread_info *tp);
 765
 766 /* Remove TP from the global pending step-over chain.  */
 767
 768 extern void global_thread_step_over_chain_remove (thread_info *tp);
 769
 770 /* Return the next thread in the step-over chain whose head is CHAIN_HEAD.
 771    Return NULL if TP is the last entry in the chain.  */
 772
 773 extern thread_info *thread_step_over_chain_next (thread_info *chain_head,
 774                                                  thread_info *tp);
 775
 776 /* Return the next thread in the global step-over chain.  Return NULL if TP is
 777    the last entry in the chain.  */
 778
 779 extern thread_info *global_thread_step_over_chain_next (thread_info *tp);
 780
 781 /* Return true if TP is in any step-over chain.  */
 782
 783 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 784
 785 /* Return the length of the the step over chain TP is in.  */
 786
 787 extern int thread_step_over_chain_length (thread_info *tp);
 788
 789 /* Cancel any ongoing execution command.  */
 790
 791 extern void thread_cancel_execution_command (struct thread_info *thr);
 792
 793 /* Check whether it makes sense to access a register of the current
 794    thread at this point.  If not, throw an error (e.g., the thread is
 795    executing).  */
 796 extern void validate_registers_access (void);
 797
 798 /* Check whether it makes sense to access a register of THREAD at this point.
 799    Returns true if registers may be accessed; false otherwise.  */
 800 extern bool can_access_registers_thread (struct thread_info *thread);
 801
 802 /* Returns whether to show which thread hit the breakpoint, received a
 803    signal, etc. and ended up causing a user-visible stop.  This is
 804    true iff we ever detected multiple threads.  */
 805 extern int show_thread_that_caused_stop (void);
 806
 807 /* Print the message for a thread or/and frame selected.  */
 808 extern void print_selected_thread_frame (struct ui_out *uiout,
 809                                          user_selected_what selection);
 810
 811 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 812    Selects thread THR.  TIDSTR is the original string the thread ID
 813    was parsed from.  This is used in the error message if THR is not
 814    alive anymore.  */
 815 extern void thread_select (const char *tidstr, class thread_info *thr);
 816
 817 #endif /* GDBTHREAD_H */