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
  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   struct regcache *regcache ();
 256   struct gdbarch *arch ();
 257
 258   ptid_t ptid;                  /* "Actual process id";
 259                                     In fact, this may be overloaded with
 260                                     kernel thread id, etc.  */
 261
 262   /* Each thread has two GDB IDs.
 263
 264      a) The thread ID (Id).  This consists of the pair of:
 265
 266         - the number of the thread's inferior and,
 267
 268         - the thread's thread number in its inferior, aka, the
 269           per-inferior thread number.  This number is unique in the
 270           inferior but not unique between inferiors.
 271
 272      b) The global ID (GId).  This is a a single integer unique
 273         between all inferiors.
 274
 275      E.g.:
 276
 277       (gdb) info threads -gid
 278         Id    GId   Target Id   Frame
 279       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 280         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 281         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 282         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 283         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 284         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 285
 286      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 287      thread has its own unique global ID.  */
 288
 289   /* The thread's global GDB thread number.  This is exposed to MI,
 290      Python/Scheme, visible with "info threads -gid", and is also what
 291      the $_gthread convenience variable is bound to.  */
 292   int global_num;
 293
 294   /* The per-inferior thread number.  This is unique in the inferior
 295      the thread belongs to, but not unique between inferiors.  This is
 296      what the $_thread convenience variable is bound to.  */
 297   int per_inf_num;
 298
 299   /* The inferior this thread belongs to.  */
 300   struct inferior *inf;
 301
 302   /* The name of the thread, as specified by the user.  This is NULL
 303      if the thread does not have a user-given name.  */
 304   char *name = NULL;
 305
 306   /* Non-zero means the thread is executing.  Note: this is different
 307      from saying that there is an active target and we are stopped at
 308      a breakpoint, for instance.  This is a real indicator whether the
 309      thread is off and running.  */
 310   int executing = 0;
 311
 312   /* Non-zero if this thread is resumed from infrun's perspective.
 313      Note that a thread can be marked both as not-executing and
 314      resumed at the same time.  This happens if we try to resume a
 315      thread that has a wait status pending.  We shouldn't let the
 316      thread really run until that wait status has been processed, but
 317      we should not process that wait status if we didn't try to let
 318      the thread run.  */
 319   int resumed = 0;
 320
 321   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 322      THREAD_STOPPED states are different from EXECUTING.  When the
 323      thread is stopped internally while handling an internal event,
 324      like a software single-step breakpoint, EXECUTING will be false,
 325      but STATE will still be THREAD_RUNNING.  */
 326   enum thread_state state = THREAD_STOPPED;
 327
 328   /* State of GDB control of inferior thread execution.
 329      See `struct thread_control_state'.  */
 330   thread_control_state control;
 331
 332   /* State of inferior thread to restore after GDB is done with an inferior
 333      call.  See `struct thread_suspend_state'.  */
 334   thread_suspend_state suspend;
 335
 336   int current_line = 0;
 337   struct symtab *current_symtab = NULL;
 338
 339   /* Internal stepping state.  */
 340
 341   /* Record the pc of the thread the last time it was resumed.  (It
 342      can't be done on stop as the PC may change since the last stop,
 343      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 344      by proceed and keep_going, and among other things, it's used in
 345      adjust_pc_after_break to distinguish a hardware single-step
 346      SIGTRAP from a breakpoint SIGTRAP.  */
 347   CORE_ADDR prev_pc = 0;
 348
 349   /* Did we set the thread stepping a breakpoint instruction?  This is
 350      used in conjunction with PREV_PC to decide whether to adjust the
 351      PC.  */
 352   int stepped_breakpoint = 0;
 353
 354   /* Should we step over breakpoint next time keep_going is called?  */
 355   int stepping_over_breakpoint = 0;
 356
 357   /* Should we step over a watchpoint next time keep_going is called?
 358      This is needed on targets with non-continuable, non-steppable
 359      watchpoints.  */
 360   int stepping_over_watchpoint = 0;
 361
 362   /* Set to TRUE if we should finish single-stepping over a breakpoint
 363      after hitting the current step-resume breakpoint.  The context here
 364      is that GDB is to do `next' or `step' while signal arrives.
 365      When stepping over a breakpoint and signal arrives, GDB will attempt
 366      to skip signal handler, so it inserts a step_resume_breakpoint at the
 367      signal return address, and resume inferior.
 368      step_after_step_resume_breakpoint is set to TRUE at this moment in
 369      order to keep GDB in mind that there is still a breakpoint to step over
 370      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 371   int step_after_step_resume_breakpoint = 0;
 372
 373   /* Pointer to the state machine manager object that handles what is
 374      left to do for the thread's execution command after the target
 375      stops.  Several execution commands use it.  */
 376   struct thread_fsm *thread_fsm = NULL;
 377
 378   /* This is used to remember when a fork or vfork event was caught by
 379      a catchpoint, and thus the event is to be followed at the next
 380      resume of the thread, and not immediately.  */
 381   struct target_waitstatus pending_follow;
 382
 383   /* True if this thread has been explicitly requested to stop.  */
 384   int stop_requested = 0;
 385
 386   /* The initiating frame of a nexting operation, used for deciding
 387      which exceptions to intercept.  If it is null_frame_id no
 388      bp_longjmp or bp_exception but longjmp has been caught just for
 389      bp_longjmp_call_dummy.  */
 390   struct frame_id initiating_frame = null_frame_id;
 391
 392   /* Private data used by the target vector implementation.  */
 393   std::unique_ptr<private_thread_info> priv;
 394
 395   /* Branch trace information for this thread.  */
 396   struct btrace_thread_info btrace {};
 397
 398   /* Flag which indicates that the stack temporaries should be stored while
 399      evaluating expressions.  */
 400   bool stack_temporaries_enabled = false;
 401
 402   /* Values that are stored as temporaries on stack while evaluating
 403      expressions.  */
 404   std::vector<struct value *> stack_temporaries;
 405
 406   /* Step-over chain.  A thread is in the step-over queue if these are
 407      non-NULL.  If only a single thread is in the chain, then these
 408      fields point to self.  */
 409   struct thread_info *step_over_prev = NULL;
 410   struct thread_info *step_over_next = NULL;
 411
 412   displaced_step_thread_state displaced_step_state;
 413 };
 414
 415 /* A gdb::ref_ptr pointer to a thread_info.  */
 416
 417 using thread_info_ref
 418   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 419
 420 /* Create an empty thread list, or empty the existing one.  */
 421 extern void init_thread_list (void);
 422
 423 /* Add a thread to the thread list, print a message
 424    that a new thread is found, and return the pointer to
 425    the new thread.  Caller my use this pointer to
 426    initialize the private thread data.  */
 427 extern struct thread_info *add_thread (ptid_t ptid);
 428
 429 /* Same as add_thread, but does not print a message
 430    about new thread.  */
 431 extern struct thread_info *add_thread_silent (ptid_t ptid);
 432
 433 /* Same as add_thread, and sets the private info.  */
 434 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 435                                                  struct private_thread_info *);
 436
 437 /* Delete an existing thread, removing the entry from its inferior's thread
 438    map.  */
 439 extern void delete_thread (struct thread_info *thread);
 440
 441 /* Like the above, but don't remove the entry from the inferior thread map.  */
 442 extern void delete_thread_noremove(struct thread_info *thread);
 443
 444 /* Delete an existing thread list entry, and be quiet about it.  Used
 445    after the process this thread having belonged to having already
 446    exited, for example.  */
 447 extern void delete_thread_silent (struct thread_info *thread);
 448
 449 /* Like the above, but don't remove the entry from the inferior thread map.  */
 450 extern void delete_thread_silent_noremove (thread_info *thread);
 451
 452 /* Delete a step_resume_breakpoint from the thread database.  */
 453 extern void delete_step_resume_breakpoint (struct thread_info *);
 454
 455 /* Delete an exception_resume_breakpoint from the thread database.  */
 456 extern void delete_exception_resume_breakpoint (struct thread_info *);
 457
 458 /* Delete the single-step breakpoints of thread TP, if any.  */
 459 extern void delete_single_step_breakpoints (struct thread_info *tp);
 460
 461 /* Check if the thread has software single stepping breakpoints
 462    set.  */
 463 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 464
 465 /* Check whether the thread has software single stepping breakpoints
 466    set at PC.  */
 467 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 468                                                    const address_space *aspace,
 469                                                    CORE_ADDR addr);
 470
 471 /* Returns whether to show inferior-qualified thread IDs, or plain
 472    thread numbers.  Inferior-qualified IDs are shown whenever we have
 473    multiple inferiors, or the only inferior left has number > 1.  */
 474 extern int show_inferior_qualified_tids (void);
 475
 476 /* Return a string version of THR's thread ID.  If there are multiple
 477    inferiors, then this prints the inferior-qualifier form, otherwise
 478    it only prints the thread number.  The result is stored in a
 479    circular static buffer, NUMCELLS deep.  */
 480 const char *print_thread_id (struct thread_info *thr);
 481
 482 /* Boolean test for an already-known ptid.  */
 483 extern int in_thread_list (ptid_t ptid);
 484
 485 /* Boolean test for an already-known global thread id (GDB's homegrown
 486    global id, not the system's).  */
 487 extern int valid_global_thread_id (int global_id);
 488
 489 /* Search function to lookup a thread by 'pid'.  */
 490 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 491
 492 /* Search function to lookup a thread by 'ptid'.  Only searches in
 493    threads of INF.  */
 494 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 495
 496 /* Find thread by GDB global thread ID.  */
 497 struct thread_info *find_thread_global_id (int global_id);
 498
 499 /* Find thread by thread library specific handle in inferior INF.  */
 500 struct thread_info *find_thread_by_handle
 501   (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
 502
 503 /* Finds the first thread of the specified inferior.  */
 504 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 505
 506 /* Returns any thread of inferior INF, giving preference to the
 507    current thread.  */
 508 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 509
 510 /* Returns any non-exited thread of inferior INF, giving preference to
 511    the current thread, and to not executing threads.  */
 512 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 513
 514 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 515 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 516
 517 /* Iterator function to call a user-provided callback function
 518    once for each known thread.  */
 519 typedef int (*thread_callback_func) (struct thread_info *, void *);
 520 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 521
 522 /* Pull in the internals of the inferiors/threads ranges and
 523    iterators.  Must be done after struct thread_info is defined.  */
 524 #include "thread-iter.h"
 525
 526 /* Return a range that can be used to walk over all threads of all
 527    inferiors, with range-for.  Used like this:
 528
 529        for (thread_info *thr : all_threads ())
 530          { .... }
 531 */
 532 inline all_threads_range
 533 all_threads ()
 534 {
 535   return {};
 536 }
 537
 538 /* Likewise, but accept a filter PTID.  */
 539
 540 inline all_matching_threads_range
 541 all_threads (ptid_t filter_ptid)
 542 {
 543   return all_matching_threads_range (filter_ptid);
 544 }
 545
 546 /* Return a range that can be used to walk over all non-exited threads
 547    of all inferiors, with range-for.  FILTER_PTID can be used to
 548    filter out thread that don't match.  */
 549
 550 inline all_non_exited_threads_range
 551 all_non_exited_threads (ptid_t filter_ptid = minus_one_ptid)
 552 {
 553   return all_non_exited_threads_range (filter_ptid);
 554 }
 555
 556 /* Return a range that can be used to walk over all threads of all
 557    inferiors, with range-for, safely.  I.e., it is safe to delete the
 558    currently-iterated thread.  When combined with range-for, this
 559    allow convenient patterns like this:
 560
 561      for (thread_info *t : all_threads_safe ())
 562        if (some_condition ())
 563          delete f;
 564 */
 565
 566 inline all_threads_safe_range
 567 all_threads_safe ()
 568 {
 569   return all_threads_safe_range ();
 570 }
 571
 572 extern int thread_count (void);
 573
 574 /* Return true if we have any thread in any inferior.  */
 575 extern bool any_thread_p ();
 576
 577 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 578 extern void switch_to_thread (struct thread_info *thr);
 579
 580 /* Switch context to no thread selected.  */
 581 extern void switch_to_no_thread ();
 582
 583 /* Switch from one thread to another.  Does not read registers.  */
 584 extern void switch_to_thread_no_regs (struct thread_info *thread);
 585
 586 /* Marks or clears thread(s) PTID as resumed.  If PTID is
 587    MINUS_ONE_PTID, applies to all threads.  If ptid_is_pid(PTID) is
 588    true, applies to all threads of the process pointed at by PTID.  */
 589 extern void set_resumed (ptid_t ptid, int resumed);
 590
 591 /* Marks thread PTID is running, or stopped.
 592    If PTID is minus_one_ptid, marks all threads.  */
 593 extern void set_running (ptid_t ptid, int running);
 594
 595 /* Marks or clears thread(s) PTID as having been requested to stop.
 596    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 597    ptid_is_pid(PTID) is true, applies to all threads of the process
 598    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 599    observer is called with PTID as argument.  */
 600 extern void set_stop_requested (ptid_t ptid, int stop);
 601
 602 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 603    marks all threads.
 604
 605    Note that this is different from the running state.  See the
 606    description of state and executing fields of struct
 607    thread_info.  */
 608 extern void set_executing (ptid_t ptid, int executing);
 609
 610 /* True if any (known or unknown) thread is or may be executing.  */
 611 extern int threads_are_executing (void);
 612
 613 /* Merge the executing property of thread PTID over to its thread
 614    state property (frontend running/stopped view).
 615
 616    "not executing" -> "stopped"
 617    "executing"     -> "running"
 618    "exited"        -> "exited"
 619
 620    If PTID is minus_one_ptid, go over all threads.
 621
 622    Notifications are only emitted if the thread state did change.  */
 623 extern void finish_thread_state (ptid_t ptid);
 624
 625 /* Calls finish_thread_state on scope exit, unless release() is called
 626    to disengage.  */
 627 using scoped_finish_thread_state
 628   = FORWARD_SCOPE_EXIT (finish_thread_state);
 629
 630 /* Commands with a prefix of `thread'.  */
 631 extern struct cmd_list_element *thread_cmd_list;
 632
 633 extern void thread_command (const char *tidstr, int from_tty);
 634
 635 /* Print notices on thread events (attach, detach, etc.), set with
 636    `set print thread-events'.  */
 637 extern bool print_thread_events;
 638
 639 /* Prints the list of threads and their details on UIOUT.  If
 640    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 641    print threads whose ID is included in the list.  If PID is not -1,
 642    only print threads from the process PID.  Otherwise, threads from
 643    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 644    NULL and PID is not -1, then the thread is printed if it belongs to
 645    the specified process.  Otherwise, an error is raised.  */
 646 extern void print_thread_info (struct ui_out *uiout,
 647                                const char *requested_threads,
 648                                int pid);
 649
 650 /* Save/restore current inferior/thread/frame.  */
 651
 652 class scoped_restore_current_thread
 653 {
 654 public:
 655   scoped_restore_current_thread ();
 656   ~scoped_restore_current_thread ();
 657
 658   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 659
 660 private:
 661   /* Use the "class" keyword here, because of a clash with a "thread_info"
 662      function in the Darwin API.  */
 663   class thread_info *m_thread;
 664   inferior *m_inf;
 665   frame_id m_selected_frame_id;
 666   int m_selected_frame_level;
 667   bool m_was_stopped;
 668 };
 669
 670 /* Returns a pointer into the thread_info corresponding to
 671    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 672 extern struct thread_info* inferior_thread (void);
 673
 674 extern void update_thread_list (void);
 675
 676 /* Delete any thread the target says is no longer alive.  */
 677
 678 extern void prune_threads (void);
 679
 680 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 681    does not consult the target about whether the thread is alive right
 682    now.  */
 683 extern void delete_exited_threads (void);
 684
 685 /* Return true if PC is in the stepping range of THREAD.  */
 686
 687 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 688
 689 /* Enable storing stack temporaries for thread THR and disable and
 690    clear the stack temporaries on destruction.  Holds a strong
 691    reference to THR.  */
 692
 693 class enable_thread_stack_temporaries
 694 {
 695 public:
 696
 697   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 698     : m_thr (thr)
 699   {
 700     gdb_assert (m_thr != NULL);
 701
 702     m_thr->incref ();
 703
 704     m_thr->stack_temporaries_enabled = true;
 705     m_thr->stack_temporaries.clear ();
 706   }
 707
 708   ~enable_thread_stack_temporaries ()
 709   {
 710     m_thr->stack_temporaries_enabled = false;
 711     m_thr->stack_temporaries.clear ();
 712
 713     m_thr->decref ();
 714   }
 715
 716   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 717
 718 private:
 719
 720   struct thread_info *m_thr;
 721 };
 722
 723 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 724
 725 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 726
 727 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 728
 729 extern bool value_in_thread_stack_temporaries (struct value *,
 730                                                struct thread_info *thr);
 731
 732 /* Add TP to the end of the global pending step-over chain.  */
 733
 734 extern void global_thread_step_over_chain_enqueue (struct thread_info *tp);
 735
 736 /* Remove TP from step-over chain LIST_P.  */
 737
 738 extern void thread_step_over_chain_remove (thread_info **list_p,
 739                                            thread_info *tp);
 740
 741 /* Remove TP from the global pending step-over chain.  */
 742
 743 extern void global_thread_step_over_chain_remove (thread_info *tp);
 744
 745 /* Return the next thread in the step-over chain whose head is CHAIN_HEAD.
 746    Return NULL if TP is the last entry in the chain.  */
 747
 748 extern thread_info *thread_step_over_chain_next (thread_info *chain_head,
 749                                                  thread_info *tp);
 750
 751 /* Return the next thread in the global step-over chain.  Return NULL if TP is
 752    the last entry in the chain.  */
 753
 754 extern thread_info *global_thread_step_over_chain_next (thread_info *tp);
 755
 756 /* Return true if TP is in any step-over chain.  */
 757
 758 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 759
 760 /* Return the length of the the step over chain TP is in.  */
 761
 762 extern int thread_step_over_chain_length (thread_info *tp);
 763
 764 /* Cancel any ongoing execution command.  */
 765
 766 extern void thread_cancel_execution_command (struct thread_info *thr);
 767
 768 /* Check whether it makes sense to access a register of the current
 769    thread at this point.  If not, throw an error (e.g., the thread is
 770    executing).  */
 771 extern void validate_registers_access (void);
 772
 773 /* Check whether it makes sense to access a register of THREAD at this point.
 774    Returns true if registers may be accessed; false otherwise.  */
 775 extern bool can_access_registers_thread (struct thread_info *thread);
 776
 777 /* Returns whether to show which thread hit the breakpoint, received a
 778    signal, etc. and ended up causing a user-visible stop.  This is
 779    true iff we ever detected multiple threads.  */
 780 extern int show_thread_that_caused_stop (void);
 781
 782 /* Print the message for a thread or/and frame selected.  */
 783 extern void print_selected_thread_frame (struct ui_out *uiout,
 784                                          user_selected_what selection);
 785
 786 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 787    Selects thread THR.  TIDSTR is the original string the thread ID
 788    was parsed from.  This is used in the error message if THR is not
 789    alive anymore.  */
 790 extern void thread_select (const char *tidstr, class thread_info *thr);
 791
 792 #endif /* GDBTHREAD_H */