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