gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2019 Free Software Foundation, Inc.
   3    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   4
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GDBTHREAD_H
  22 #define GDBTHREAD_H
  23
  24 struct symtab;
  25
  26 #include "breakpoint.h"
  27 #include "frame.h"
  28 #include "ui-out.h"
  29 #include "btrace.h"
  30 #include "target/waitstatus.h"
  31 #include "cli/cli-utils.h"
  32 #include "gdbsupport/refcounted-object.h"
  33 #include "gdbsupport/common-gdbthread.h"
  34 #include "gdbsupport/forward-scope-exit.h"
  35
  36 struct inferior;
  37
  38 /* Frontend view of the thread state.  Possible extensions: stepping,
  39    finishing, until(ling),...
  40
  41    NOTE: Since the thread state is not a boolean, most times, you do
  42    not want to check it with negation.  If you really want to check if
  43    the thread is stopped,
  44
  45     use (good):
  46
  47      if (tp->state == THREAD_STOPPED)
  48
  49     instead of (bad):
  50
  51      if (tp->state != THREAD_RUNNING)
  52
  53    The latter is also true for exited threads, most likely not what
  54    you want.  */
  55 enum thread_state
  56 {
  57   /* In the frontend's perpective, the thread is stopped.  */
  58   THREAD_STOPPED,
  59
  60   /* In the frontend's perpective, the thread is running.  */
  61   THREAD_RUNNING,
  62
  63   /* The thread is listed, but known to have exited.  We keep it
  64      listed (but not visible) until it's safe to delete it.  */
  65   THREAD_EXITED,
  66 };
  67
  68 /* STEP_OVER_ALL means step over all subroutine calls.
  69    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  70    STEP_OVER_NONE means don't step over any subroutine calls.  */
  71
  72 enum step_over_calls_kind
  73   {
  74     STEP_OVER_NONE,
  75     STEP_OVER_ALL,
  76     STEP_OVER_UNDEBUGGABLE
  77   };
  78
  79 /* Inferior thread specific part of `struct infcall_control_state'.
  80
  81    Inferior process counterpart is `struct inferior_control_state'.  */
  82
  83 struct thread_control_state
  84 {
  85   /* User/external stepping state.  */
  86
  87   /* Step-resume or longjmp-resume breakpoint.  */
  88   struct breakpoint *step_resume_breakpoint = nullptr;
  89
  90   /* Exception-resume breakpoint.  */
  91   struct breakpoint *exception_resume_breakpoint = nullptr;
  92
  93   /* Breakpoints used for software single stepping.  Plural, because
  94      it may have multiple locations.  E.g., if stepping over a
  95      conditional branch instruction we can't decode the condition for,
  96      we'll need to put a breakpoint at the branch destination, and
  97      another at the instruction after the branch.  */
  98   struct breakpoint *single_step_breakpoints = nullptr;
  99
 100   /* Range to single step within.
 101
 102      If this is nonzero, respond to a single-step signal by continuing
 103      to step if the pc is in this range.
 104
 105      If step_range_start and step_range_end are both 1, it means to
 106      step for a single instruction (FIXME: it might clean up
 107      wait_for_inferior in a minor way if this were changed to the
 108      address of the instruction and that address plus one.  But maybe
 109      not).  */
 110   CORE_ADDR step_range_start = 0;       /* Inclusive */
 111   CORE_ADDR step_range_end = 0;         /* Exclusive */
 112
 113   /* Function the thread was in as of last it started stepping.  */
 114   struct symbol *step_start_function = nullptr;
 115
 116   /* If GDB issues a target step request, and this is nonzero, the
 117      target should single-step this thread once, and then continue
 118      single-stepping it without GDB core involvement as long as the
 119      thread stops in the step range above.  If this is zero, the
 120      target should ignore the step range, and only issue one single
 121      step.  */
 122   int may_range_step = 0;
 123
 124   /* Stack frame address as of when stepping command was issued.
 125      This is how we know when we step into a subroutine call, and how
 126      to set the frame for the breakpoint used to step out.  */
 127   struct frame_id step_frame_id {};
 128
 129   /* Similarly, the frame ID of the underlying stack frame (skipping
 130      any inlined frames).  */
 131   struct frame_id step_stack_frame_id {};
 132
 133   /* Nonzero if we are presently stepping over a breakpoint.
 134
 135      If we hit a breakpoint or watchpoint, and then continue, we need
 136      to single step the current thread with breakpoints disabled, to
 137      avoid hitting the same breakpoint or watchpoint again.  And we
 138      should step just a single thread and keep other threads stopped,
 139      so that other threads don't miss breakpoints while they are
 140      removed.
 141
 142      So, this variable simultaneously means that we need to single
 143      step the current thread, keep other threads stopped, and that
 144      breakpoints should be removed while we step.
 145
 146      This variable is set either:
 147      - in proceed, when we resume inferior on user's explicit request
 148      - in keep_going, if handle_inferior_event decides we need to
 149      step over breakpoint.
 150
 151      The variable is cleared in normal_stop.  The proceed calls
 152      wait_for_inferior, which calls handle_inferior_event in a loop,
 153      and until wait_for_inferior exits, this variable is changed only
 154      by keep_going.  */
 155   int trap_expected = 0;
 156
 157   /* Nonzero if the thread is being proceeded for a "finish" command
 158      or a similar situation when return value should be printed.  */
 159   int proceed_to_finish = 0;
 160
 161   /* Nonzero if the thread is being proceeded for an inferior function
 162      call.  */
 163   int in_infcall = 0;
 164
 165   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 166
 167   /* Nonzero if stopped due to a step command.  */
 168   int stop_step = 0;
 169
 170   /* Chain containing status of breakpoint(s) the thread stopped
 171      at.  */
 172   bpstat stop_bpstat = nullptr;
 173
 174   /* Whether the command that started the thread was a stepping
 175      command.  This is used to decide whether "set scheduler-locking
 176      step" behaves like "on" or "off".  */
 177   int stepping_command = 0;
 178 };
 179
 180 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 181
 182 struct thread_suspend_state
 183 {
 184   /* Last signal that the inferior received (why it stopped).  When
 185      the thread is resumed, this signal is delivered.  Note: the
 186      target should not check whether the signal is in pass state,
 187      because the signal may have been explicitly passed with the
 188      "signal" command, which overrides "handle nopass".  If the signal
 189      should be suppressed, the core will take care of clearing this
 190      before the target is resumed.  */
 191   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 192
 193   /* The reason the thread last stopped, if we need to track it
 194      (breakpoint, watchpoint, etc.)  */
 195   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 196
 197   /* The waitstatus for this thread's last event.  */
 198   struct target_waitstatus waitstatus {};
 199   /* If true WAITSTATUS hasn't been handled yet.  */
 200   int waitstatus_pending_p = 0;
 201
 202   /* Record the pc of the thread the last time it stopped.  (This is
 203      not the current thread's PC as that may have changed since the
 204      last stop, e.g., "return" command, or "p $pc = 0xf000").
 205
 206      - If the thread's PC has not changed since the thread last
 207        stopped, then proceed skips a breakpoint at the current PC,
 208        otherwise we let the thread run into the breakpoint.
 209
 210      - If the thread has an unprocessed event pending, as indicated by
 211        waitstatus_pending_p, this is used in coordination with
 212        stop_reason: if the thread's PC has changed since the thread
 213        last stopped, a pending breakpoint waitstatus is discarded.
 214
 215      - If the thread is running, this is set to -1, to avoid leaving
 216        it with a stale value, to make it easier to catch bugs.  */
 217   CORE_ADDR stop_pc = 0;
 218 };
 219
 220 /* Base class for target-specific thread data.  */
 221 struct private_thread_info
 222 {
 223   virtual ~private_thread_info () = 0;
 224 };
 225
 226 /* Threads are intrusively refcounted objects.  Being the
 227    user-selected thread is normally considered an implicit strong
 228    reference and is thus not accounted in the refcount, unlike
 229    inferior objects.  This is necessary, because there's no "current
 230    thread" pointer.  Instead the current thread is inferred from the
 231    inferior_ptid global.  However, when GDB needs to remember the
 232    selected thread to later restore it, GDB bumps the thread object's
 233    refcount, to prevent something deleting the thread object before
 234    reverting back (e.g., due to a "kill" command).  If the thread
 235    meanwhile exits before being re-selected, then the thread object is
 236    left listed in the thread list, but marked with state
 237    THREAD_EXITED.  (See scoped_restore_current_thread and
 238    delete_thread).  All other thread references are considered weak
 239    references.  Placing a thread in the thread list is an implicit
 240    strong reference, and is thus not accounted for in the thread's
 241    refcount.  */
 242
 243 class thread_info : public refcounted_object
 244 {
 245 public:
 246   explicit thread_info (inferior *inf, ptid_t ptid);
 247   ~thread_info ();
 248
 249   bool deletable () const;
 250
 251   /* Mark this thread as running and notify observers.  */
 252   void set_running (bool running);
 253
 254   ptid_t ptid;                  /* "Actual process id";
 255                                     In fact, this may be overloaded with
 256                                     kernel thread id, etc.  */
 257
 258   /* Each thread has two GDB IDs.
 259
 260      a) The thread ID (Id).  This consists of the pair of:
 261
 262         - the number of the thread's inferior and,
 263
 264         - the thread's thread number in its inferior, aka, the
 265           per-inferior thread number.  This number is unique in the
 266           inferior but not unique between inferiors.
 267
 268      b) The global ID (GId).  This is a a single integer unique
 269         between all inferiors.
 270
 271      E.g.:
 272
 273       (gdb) info threads -gid
 274         Id    GId   Target Id   Frame
 275       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 276         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 277         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 278         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 279         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 280         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 281
 282      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 283      thread has its own unique global ID.  */
 284
 285   /* The thread's global GDB thread number.  This is exposed to MI,
 286      Python/Scheme, visible with "info threads -gid", and is also what
 287      the $_gthread convenience variable is bound to.  */
 288   int global_num;
 289
 290   /* The per-inferior thread number.  This is unique in the inferior
 291      the thread belongs to, but not unique between inferiors.  This is
 292      what the $_thread convenience variable is bound to.  */
 293   int per_inf_num;
 294
 295   /* The inferior this thread belongs to.  */
 296   struct inferior *inf;
 297
 298   /* The name of the thread, as specified by the user.  This is NULL
 299      if the thread does not have a user-given name.  */
 300   char *name = NULL;
 301
 302   /* Non-zero means the thread is executing.  Note: this is different
 303      from saying that there is an active target and we are stopped at
 304      a breakpoint, for instance.  This is a real indicator whether the
 305      thread is off and running.  */
 306   int executing = 0;
 307
 308   /* Non-zero if this thread is resumed from infrun's perspective.
 309      Note that a thread can be marked both as not-executing and
 310      resumed at the same time.  This happens if we try to resume a
 311      thread that has a wait status pending.  We shouldn't let the
 312      thread really run until that wait status has been processed, but
 313      we should not process that wait status if we didn't try to let
 314      the thread run.  */
 315   int resumed = 0;
 316
 317   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 318      THREAD_STOPPED states are different from EXECUTING.  When the
 319      thread is stopped internally while handling an internal event,
 320      like a software single-step breakpoint, EXECUTING will be false,
 321      but STATE will still be THREAD_RUNNING.  */
 322   enum thread_state state = THREAD_STOPPED;
 323
 324   /* State of GDB control of inferior thread execution.
 325      See `struct thread_control_state'.  */
 326   thread_control_state control;
 327
 328   /* State of inferior thread to restore after GDB is done with an inferior
 329      call.  See `struct thread_suspend_state'.  */
 330   thread_suspend_state suspend;
 331
 332   int current_line = 0;
 333   struct symtab *current_symtab = NULL;
 334
 335   /* Internal stepping state.  */
 336
 337   /* Record the pc of the thread the last time it was resumed.  (It
 338      can't be done on stop as the PC may change since the last stop,
 339      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 340      by proceed and keep_going, and among other things, it's used in
 341      adjust_pc_after_break to distinguish a hardware single-step
 342      SIGTRAP from a breakpoint SIGTRAP.  */
 343   CORE_ADDR prev_pc = 0;
 344
 345   /* Did we set the thread stepping a breakpoint instruction?  This is
 346      used in conjunction with PREV_PC to decide whether to adjust the
 347      PC.  */
 348   int stepped_breakpoint = 0;
 349
 350   /* Should we step over breakpoint next time keep_going is called?  */
 351   int stepping_over_breakpoint = 0;
 352
 353   /* Should we step over a watchpoint next time keep_going is called?
 354      This is needed on targets with non-continuable, non-steppable
 355      watchpoints.  */
 356   int stepping_over_watchpoint = 0;
 357
 358   /* Set to TRUE if we should finish single-stepping over a breakpoint
 359      after hitting the current step-resume breakpoint.  The context here
 360      is that GDB is to do `next' or `step' while signal arrives.
 361      When stepping over a breakpoint and signal arrives, GDB will attempt
 362      to skip signal handler, so it inserts a step_resume_breakpoint at the
 363      signal return address, and resume inferior.
 364      step_after_step_resume_breakpoint is set to TRUE at this moment in
 365      order to keep GDB in mind that there is still a breakpoint to step over
 366      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 367   int step_after_step_resume_breakpoint = 0;
 368
 369   /* Pointer to the state machine manager object that handles what is
 370      left to do for the thread's execution command after the target
 371      stops.  Several execution commands use it.  */
 372   struct thread_fsm *thread_fsm = NULL;
 373
 374   /* This is used to remember when a fork or vfork event was caught by
 375      a catchpoint, and thus the event is to be followed at the next
 376      resume of the thread, and not immediately.  */
 377   struct target_waitstatus pending_follow;
 378
 379   /* True if this thread has been explicitly requested to stop.  */
 380   int stop_requested = 0;
 381
 382   /* The initiating frame of a nexting operation, used for deciding
 383      which exceptions to intercept.  If it is null_frame_id no
 384      bp_longjmp or bp_exception but longjmp has been caught just for
 385      bp_longjmp_call_dummy.  */
 386   struct frame_id initiating_frame = null_frame_id;
 387
 388   /* Private data used by the target vector implementation.  */
 389   std::unique_ptr<private_thread_info> priv;
 390
 391   /* Branch trace information for this thread.  */
 392   struct btrace_thread_info btrace {};
 393
 394   /* Flag which indicates that the stack temporaries should be stored while
 395      evaluating expressions.  */
 396   bool stack_temporaries_enabled = false;
 397
 398   /* Values that are stored as temporaries on stack while evaluating
 399      expressions.  */
 400   std::vector<struct value *> stack_temporaries;
 401
 402   /* Step-over chain.  A thread is in the step-over queue if these are
 403      non-NULL.  If only a single thread is in the chain, then these
 404      fields point to self.  */
 405   struct thread_info *step_over_prev = NULL;
 406   struct thread_info *step_over_next = NULL;
 407 };
 408
 409 /* A gdb::ref_ptr pointer to a thread_info.  */
 410
 411 using thread_info_ref
 412   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 413
 414 /* Create an empty thread list, or empty the existing one.  */
 415 extern void init_thread_list (void);
 416
 417 /* Add a thread to the thread list, print a message
 418    that a new thread is found, and return the pointer to
 419    the new thread.  Caller my use this pointer to
 420    initialize the private thread data.  */
 421 extern struct thread_info *add_thread (ptid_t ptid);
 422
 423 /* Same as add_thread, but does not print a message
 424    about new thread.  */
 425 extern struct thread_info *add_thread_silent (ptid_t ptid);
 426
 427 /* Same as add_thread, and sets the private info.  */
 428 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 429                                                  struct private_thread_info *);
 430
 431 /* Delete an existing thread, removing the entry from its inferior's thread
 432    map.  */
 433 extern void delete_thread (struct thread_info *thread);
 434
 435 /* Like the above, but don't remove the entry from the inferior thread map.  */
 436 extern void delete_thread_noremove(struct thread_info *thread);
 437
 438 /* Delete an existing thread list entry, and be quiet about it.  Used
 439    after the process this thread having belonged to having already
 440    exited, for example.  */
 441 extern void delete_thread_silent (struct thread_info *thread);
 442
 443 /* Like the above, but don't remove the entry from the inferior thread map.  */
 444 extern void delete_thread_silent_noremove (thread_info *thread);
 445
 446 /* Delete a step_resume_breakpoint from the thread database.  */
 447 extern void delete_step_resume_breakpoint (struct thread_info *);
 448
 449 /* Delete an exception_resume_breakpoint from the thread database.  */
 450 extern void delete_exception_resume_breakpoint (struct thread_info *);
 451
 452 /* Delete the single-step breakpoints of thread TP, if any.  */
 453 extern void delete_single_step_breakpoints (struct thread_info *tp);
 454
 455 /* Check if the thread has software single stepping breakpoints
 456    set.  */
 457 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 458
 459 /* Check whether the thread has software single stepping breakpoints
 460    set at PC.  */
 461 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 462                                                    const address_space *aspace,
 463                                                    CORE_ADDR addr);
 464
 465 /* Returns whether to show inferior-qualified thread IDs, or plain
 466    thread numbers.  Inferior-qualified IDs are shown whenever we have
 467    multiple inferiors, or the only inferior left has number > 1.  */
 468 extern int show_inferior_qualified_tids (void);
 469
 470 /* Return a string version of THR's thread ID.  If there are multiple
 471    inferiors, then this prints the inferior-qualifier form, otherwise
 472    it only prints the thread number.  The result is stored in a
 473    circular static buffer, NUMCELLS deep.  */
 474 const char *print_thread_id (struct thread_info *thr);
 475
 476 /* Boolean test for an already-known ptid.  */
 477 extern int in_thread_list (ptid_t ptid);
 478
 479 /* Boolean test for an already-known global thread id (GDB's homegrown
 480    global id, not the system's).  */
 481 extern int valid_global_thread_id (int global_id);
 482
 483 /* Search function to lookup a thread by 'pid'.  */
 484 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 485
 486 /* Search function to lookup a thread by 'ptid'.  Only searches in
 487    threads of INF.  */
 488 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 489
 490 /* Find thread by GDB global thread ID.  */
 491 struct thread_info *find_thread_global_id (int global_id);
 492
 493 /* Find thread by thread library specific handle in inferior INF.  */
 494 struct thread_info *find_thread_by_handle
 495   (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
 496
 497 /* Finds the first thread of the specified inferior.  */
 498 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 499
 500 /* Returns any thread of inferior INF, giving preference to the
 501    current thread.  */
 502 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 503
 504 /* Returns any non-exited thread of inferior INF, giving preference to
 505    the current thread, and to not executing threads.  */
 506 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 507
 508 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 509 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 510
 511 /* Iterator function to call a user-provided callback function
 512    once for each known thread.  */
 513 typedef int (*thread_callback_func) (struct thread_info *, void *);
 514 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 515
 516 /* Pull in the internals of the inferiors/threads ranges and
 517    iterators.  Must be done after struct thread_info is defined.  */
 518 #include "thread-iter.h"
 519
 520 /* Return a range that can be used to walk over all threads of all
 521    inferiors, with range-for.  Used like this:
 522
 523        for (thread_info *thr : all_threads ())
 524          { .... }
 525 */
 526 inline all_threads_range
 527 all_threads ()
 528 {
 529   return {};
 530 }
 531
 532 /* Likewise, but accept a filter PTID.  */
 533
 534 inline all_matching_threads_range
 535 all_threads (ptid_t filter_ptid)
 536 {
 537   return all_matching_threads_range (filter_ptid);
 538 }
 539
 540 /* Return a range that can be used to walk over all non-exited threads
 541    of all inferiors, with range-for.  FILTER_PTID can be used to
 542    filter out thread that don't match.  */
 543
 544 inline all_non_exited_threads_range
 545 all_non_exited_threads (ptid_t filter_ptid = minus_one_ptid)
 546 {
 547   return all_non_exited_threads_range (filter_ptid);
 548 }
 549
 550 /* Return a range that can be used to walk over all threads of all
 551    inferiors, with range-for, safely.  I.e., it is safe to delete the
 552    currently-iterated thread.  When combined with range-for, this
 553    allow convenient patterns like this:
 554
 555      for (thread_info *t : all_threads_safe ())
 556        if (some_condition ())
 557          delete f;
 558 */
 559
 560 inline all_threads_safe_range
 561 all_threads_safe ()
 562 {
 563   return all_threads_safe_range ();
 564 }
 565
 566 extern int thread_count (void);
 567
 568 /* Return true if we have any thread in any inferior.  */
 569 extern bool any_thread_p ();
 570
 571 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 572 extern void switch_to_thread (struct thread_info *thr);
 573
 574 /* Switch context to no thread selected.  */
 575 extern void switch_to_no_thread ();
 576
 577 /* Switch from one thread to another.  Does not read registers.  */
 578 extern void switch_to_thread_no_regs (struct thread_info *thread);
 579
 580 /* Marks or clears thread(s) PTID as resumed.  If PTID is
 581    MINUS_ONE_PTID, applies to all threads.  If ptid_is_pid(PTID) is
 582    true, applies to all threads of the process pointed at by PTID.  */
 583 extern void set_resumed (ptid_t ptid, int resumed);
 584
 585 /* Marks thread PTID is running, or stopped.
 586    If PTID is minus_one_ptid, marks all threads.  */
 587 extern void set_running (ptid_t ptid, int running);
 588
 589 /* Marks or clears thread(s) PTID as having been requested to stop.
 590    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 591    ptid_is_pid(PTID) is true, applies to all threads of the process
 592    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 593    observer is called with PTID as argument.  */
 594 extern void set_stop_requested (ptid_t ptid, int stop);
 595
 596 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 597    marks all threads.
 598
 599    Note that this is different from the running state.  See the
 600    description of state and executing fields of struct
 601    thread_info.  */
 602 extern void set_executing (ptid_t ptid, int executing);
 603
 604 /* True if any (known or unknown) thread is or may be executing.  */
 605 extern int threads_are_executing (void);
 606
 607 /* Merge the executing property of thread PTID over to its thread
 608    state property (frontend running/stopped view).
 609
 610    "not executing" -> "stopped"
 611    "executing"     -> "running"
 612    "exited"        -> "exited"
 613
 614    If PTID is minus_one_ptid, go over all threads.
 615
 616    Notifications are only emitted if the thread state did change.  */
 617 extern void finish_thread_state (ptid_t ptid);
 618
 619 /* Calls finish_thread_state on scope exit, unless release() is called
 620    to disengage.  */
 621 using scoped_finish_thread_state
 622   = FORWARD_SCOPE_EXIT (finish_thread_state);
 623
 624 /* Commands with a prefix of `thread'.  */
 625 extern struct cmd_list_element *thread_cmd_list;
 626
 627 extern void thread_command (const char *tidstr, int from_tty);
 628
 629 /* Print notices on thread events (attach, detach, etc.), set with
 630    `set print thread-events'.  */
 631 extern bool print_thread_events;
 632
 633 /* Prints the list of threads and their details on UIOUT.  If
 634    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 635    print threads whose ID is included in the list.  If PID is not -1,
 636    only print threads from the process PID.  Otherwise, threads from
 637    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 638    NULL and PID is not -1, then the thread is printed if it belongs to
 639    the specified process.  Otherwise, an error is raised.  */
 640 extern void print_thread_info (struct ui_out *uiout,
 641                                const char *requested_threads,
 642                                int pid);
 643
 644 /* Save/restore current inferior/thread/frame.  */
 645
 646 class scoped_restore_current_thread
 647 {
 648 public:
 649   scoped_restore_current_thread ();
 650   ~scoped_restore_current_thread ();
 651
 652   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 653
 654 private:
 655   /* Use the "class" keyword here, because of a clash with a "thread_info"
 656      function in the Darwin API.  */
 657   class thread_info *m_thread;
 658   inferior *m_inf;
 659   frame_id m_selected_frame_id;
 660   int m_selected_frame_level;
 661   bool m_was_stopped;
 662 };
 663
 664 /* Returns a pointer into the thread_info corresponding to
 665    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 666 extern struct thread_info* inferior_thread (void);
 667
 668 extern void update_thread_list (void);
 669
 670 /* Delete any thread the target says is no longer alive.  */
 671
 672 extern void prune_threads (void);
 673
 674 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 675    does not consult the target about whether the thread is alive right
 676    now.  */
 677 extern void delete_exited_threads (void);
 678
 679 /* Return true if PC is in the stepping range of THREAD.  */
 680
 681 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 682
 683 /* Enable storing stack temporaries for thread THR and disable and
 684    clear the stack temporaries on destruction.  Holds a strong
 685    reference to THR.  */
 686
 687 class enable_thread_stack_temporaries
 688 {
 689 public:
 690
 691   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 692     : m_thr (thr)
 693   {
 694     gdb_assert (m_thr != NULL);
 695
 696     m_thr->incref ();
 697
 698     m_thr->stack_temporaries_enabled = true;
 699     m_thr->stack_temporaries.clear ();
 700   }
 701
 702   ~enable_thread_stack_temporaries ()
 703   {
 704     m_thr->stack_temporaries_enabled = false;
 705     m_thr->stack_temporaries.clear ();
 706
 707     m_thr->decref ();
 708   }
 709
 710   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 711
 712 private:
 713
 714   struct thread_info *m_thr;
 715 };
 716
 717 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 718
 719 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 720
 721 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 722
 723 extern bool value_in_thread_stack_temporaries (struct value *,
 724                                                struct thread_info *thr);
 725
 726 /* Add TP to the end of its inferior's pending step-over chain.  */
 727
 728 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 729
 730 /* Remove TP from its inferior's pending step-over chain.  */
 731
 732 extern void thread_step_over_chain_remove (struct thread_info *tp);
 733
 734 /* Return the next thread in the step-over chain starting at TP.  NULL
 735    if TP is the last entry in the chain.  */
 736
 737 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 738
 739 /* Return true if TP is in the step-over chain.  */
 740
 741 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 742
 743 /* Cancel any ongoing execution command.  */
 744
 745 extern void thread_cancel_execution_command (struct thread_info *thr);
 746
 747 /* Check whether it makes sense to access a register of the current
 748    thread at this point.  If not, throw an error (e.g., the thread is
 749    executing).  */
 750 extern void validate_registers_access (void);
 751
 752 /* Check whether it makes sense to access a register of THREAD at this point.
 753    Returns true if registers may be accessed; false otherwise.  */
 754 extern bool can_access_registers_thread (struct thread_info *thread);
 755
 756 /* Returns whether to show which thread hit the breakpoint, received a
 757    signal, etc. and ended up causing a user-visible stop.  This is
 758    true iff we ever detected multiple threads.  */
 759 extern int show_thread_that_caused_stop (void);
 760
 761 /* Print the message for a thread or/and frame selected.  */
 762 extern void print_selected_thread_frame (struct ui_out *uiout,
 763                                          user_selected_what selection);
 764
 765 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 766    Selects thread THR.  TIDSTR is the original string the thread ID
 767    was parsed from.  This is used in the error message if THR is not
 768    alive anymore.  */
 769 extern void thread_select (const char *tidstr, class thread_info *thr);
 770
 771 #endif /* GDBTHREAD_H */