gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2020 Free Software Foundation, Inc.
   3    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   4
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GDBTHREAD_H
  22 #define GDBTHREAD_H
  23
  24 struct symtab;
  25
  26 #include "breakpoint.h"
  27 #include "frame.h"
  28 #include "ui-out.h"
  29 #include "btrace.h"
  30 #include "target/waitstatus.h"
  31 #include "cli/cli-utils.h"
  32 #include "gdbsupport/refcounted-object.h"
  33 #include "gdbsupport/common-gdbthread.h"
  34 #include "gdbsupport/forward-scope-exit.h"
  35
  36 struct inferior;
  37 struct process_stratum_target;
  38
  39 /* Frontend view of the thread state.  Possible extensions: stepping,
  40    finishing, until(ling),...
  41
  42    NOTE: Since the thread state is not a boolean, most times, you do
  43    not want to check it with negation.  If you really want to check if
  44    the thread is stopped,
  45
  46     use (good):
  47
  48      if (tp->state == THREAD_STOPPED)
  49
  50     instead of (bad):
  51
  52      if (tp->state != THREAD_RUNNING)
  53
  54    The latter is also true for exited threads, most likely not what
  55    you want.  */
  56 enum thread_state
  57 {
  58   /* In the frontend's perpective, the thread is stopped.  */
  59   THREAD_STOPPED,
  60
  61   /* In the frontend's perpective, the thread is running.  */
  62   THREAD_RUNNING,
  63
  64   /* The thread is listed, but known to have exited.  We keep it
  65      listed (but not visible) until it's safe to delete it.  */
  66   THREAD_EXITED,
  67 };
  68
  69 /* STEP_OVER_ALL means step over all subroutine calls.
  70    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  71    STEP_OVER_NONE means don't step over any subroutine calls.  */
  72
  73 enum step_over_calls_kind
  74   {
  75     STEP_OVER_NONE,
  76     STEP_OVER_ALL,
  77     STEP_OVER_UNDEBUGGABLE
  78   };
  79
  80 /* Inferior thread specific part of `struct infcall_control_state'.
  81
  82    Inferior process counterpart is `struct inferior_control_state'.  */
  83
  84 struct thread_control_state
  85 {
  86   /* User/external stepping state.  */
  87
  88   /* Step-resume or longjmp-resume breakpoint.  */
  89   struct breakpoint *step_resume_breakpoint = nullptr;
  90
  91   /* Exception-resume breakpoint.  */
  92   struct breakpoint *exception_resume_breakpoint = nullptr;
  93
  94   /* Breakpoints used for software single stepping.  Plural, because
  95      it may have multiple locations.  E.g., if stepping over a
  96      conditional branch instruction we can't decode the condition for,
  97      we'll need to put a breakpoint at the branch destination, and
  98      another at the instruction after the branch.  */
  99   struct breakpoint *single_step_breakpoints = nullptr;
 100
 101   /* Range to single step within.
 102
 103      If this is nonzero, respond to a single-step signal by continuing
 104      to step if the pc is in this range.
 105
 106      If step_range_start and step_range_end are both 1, it means to
 107      step for a single instruction (FIXME: it might clean up
 108      wait_for_inferior in a minor way if this were changed to the
 109      address of the instruction and that address plus one.  But maybe
 110      not).  */
 111   CORE_ADDR step_range_start = 0;       /* Inclusive */
 112   CORE_ADDR step_range_end = 0;         /* Exclusive */
 113
 114   /* Function the thread was in as of last it started stepping.  */
 115   struct symbol *step_start_function = nullptr;
 116
 117   /* If GDB issues a target step request, and this is nonzero, the
 118      target should single-step this thread once, and then continue
 119      single-stepping it without GDB core involvement as long as the
 120      thread stops in the step range above.  If this is zero, the
 121      target should ignore the step range, and only issue one single
 122      step.  */
 123   int may_range_step = 0;
 124
 125   /* Stack frame address as of when stepping command was issued.
 126      This is how we know when we step into a subroutine call, and how
 127      to set the frame for the breakpoint used to step out.  */
 128   struct frame_id step_frame_id {};
 129
 130   /* Similarly, the frame ID of the underlying stack frame (skipping
 131      any inlined frames).  */
 132   struct frame_id step_stack_frame_id {};
 133
 134   /* True if the the thread is presently stepping over a breakpoint or
 135      a watchpoint, either with an inline step over or a displaced (out
 136      of line) step, and we're now expecting it to report a trap for
 137      the finished single step.  */
 138   int trap_expected = 0;
 139
 140   /* Nonzero if the thread is being proceeded for a "finish" command
 141      or a similar situation when return value should be printed.  */
 142   int proceed_to_finish = 0;
 143
 144   /* Nonzero if the thread is being proceeded for an inferior function
 145      call.  */
 146   int in_infcall = 0;
 147
 148   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 149
 150   /* Nonzero if stopped due to a step command.  */
 151   int stop_step = 0;
 152
 153   /* Chain containing status of breakpoint(s) the thread stopped
 154      at.  */
 155   bpstat stop_bpstat = nullptr;
 156
 157   /* Whether the command that started the thread was a stepping
 158      command.  This is used to decide whether "set scheduler-locking
 159      step" behaves like "on" or "off".  */
 160   int stepping_command = 0;
 161 };
 162
 163 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 164
 165 struct thread_suspend_state
 166 {
 167   /* Last signal that the inferior received (why it stopped).  When
 168      the thread is resumed, this signal is delivered.  Note: the
 169      target should not check whether the signal is in pass state,
 170      because the signal may have been explicitly passed with the
 171      "signal" command, which overrides "handle nopass".  If the signal
 172      should be suppressed, the core will take care of clearing this
 173      before the target is resumed.  */
 174   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 175
 176   /* The reason the thread last stopped, if we need to track it
 177      (breakpoint, watchpoint, etc.)  */
 178   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 179
 180   /* The waitstatus for this thread's last event.  */
 181   struct target_waitstatus waitstatus {};
 182   /* If true WAITSTATUS hasn't been handled yet.  */
 183   int waitstatus_pending_p = 0;
 184
 185   /* Record the pc of the thread the last time it stopped.  (This is
 186      not the current thread's PC as that may have changed since the
 187      last stop, e.g., "return" command, or "p $pc = 0xf000").
 188
 189      - If the thread's PC has not changed since the thread last
 190        stopped, then proceed skips a breakpoint at the current PC,
 191        otherwise we let the thread run into the breakpoint.
 192
 193      - If the thread has an unprocessed event pending, as indicated by
 194        waitstatus_pending_p, this is used in coordination with
 195        stop_reason: if the thread's PC has changed since the thread
 196        last stopped, a pending breakpoint waitstatus is discarded.
 197
 198      - If the thread is running, this is set to -1, to avoid leaving
 199        it with a stale value, to make it easier to catch bugs.  */
 200   CORE_ADDR stop_pc = 0;
 201 };
 202
 203 /* Base class for target-specific thread data.  */
 204 struct private_thread_info
 205 {
 206   virtual ~private_thread_info () = 0;
 207 };
 208
 209 /* Threads are intrusively refcounted objects.  Being the
 210    user-selected thread is normally considered an implicit strong
 211    reference and is thus not accounted in the refcount, unlike
 212    inferior objects.  This is necessary, because there's no "current
 213    thread" pointer.  Instead the current thread is inferred from the
 214    inferior_ptid global.  However, when GDB needs to remember the
 215    selected thread to later restore it, GDB bumps the thread object's
 216    refcount, to prevent something deleting the thread object before
 217    reverting back (e.g., due to a "kill" command).  If the thread
 218    meanwhile exits before being re-selected, then the thread object is
 219    left listed in the thread list, but marked with state
 220    THREAD_EXITED.  (See scoped_restore_current_thread and
 221    delete_thread).  All other thread references are considered weak
 222    references.  Placing a thread in the thread list is an implicit
 223    strong reference, and is thus not accounted for in the thread's
 224    refcount.  */
 225
 226 class thread_info : public refcounted_object
 227 {
 228 public:
 229   explicit thread_info (inferior *inf, ptid_t ptid);
 230   ~thread_info ();
 231
 232   bool deletable () const;
 233
 234   /* Mark this thread as running and notify observers.  */
 235   void set_running (bool running);
 236
 237   struct thread_info *next = NULL;
 238   ptid_t ptid;                  /* "Actual process id";
 239                                     In fact, this may be overloaded with
 240                                     kernel thread id, etc.  */
 241
 242   /* Each thread has two GDB IDs.
 243
 244      a) The thread ID (Id).  This consists of the pair of:
 245
 246         - the number of the thread's inferior and,
 247
 248         - the thread's thread number in its inferior, aka, the
 249           per-inferior thread number.  This number is unique in the
 250           inferior but not unique between inferiors.
 251
 252      b) The global ID (GId).  This is a a single integer unique
 253         between all inferiors.
 254
 255      E.g.:
 256
 257       (gdb) info threads -gid
 258         Id    GId   Target Id   Frame
 259       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 260         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 261         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 262         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 263         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 264         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 265
 266      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 267      thread has its own unique global ID.  */
 268
 269   /* The thread's global GDB thread number.  This is exposed to MI,
 270      Python/Scheme, visible with "info threads -gid", and is also what
 271      the $_gthread convenience variable is bound to.  */
 272   int global_num;
 273
 274   /* The per-inferior thread number.  This is unique in the inferior
 275      the thread belongs to, but not unique between inferiors.  This is
 276      what the $_thread convenience variable is bound to.  */
 277   int per_inf_num;
 278
 279   /* The inferior this thread belongs to.  */
 280   struct inferior *inf;
 281
 282   /* The name of the thread, as specified by the user.  This is NULL
 283      if the thread does not have a user-given name.  */
 284   char *name = NULL;
 285
 286   /* True means the thread is executing.  Note: this is different
 287      from saying that there is an active target and we are stopped at
 288      a breakpoint, for instance.  This is a real indicator whether the
 289      thread is off and running.  */
 290   bool executing = false;
 291
 292   /* True if this thread is resumed from infrun's perspective.
 293      Note that a thread can be marked both as not-executing and
 294      resumed at the same time.  This happens if we try to resume a
 295      thread that has a wait status pending.  We shouldn't let the
 296      thread really run until that wait status has been processed, but
 297      we should not process that wait status if we didn't try to let
 298      the thread run.  */
 299   bool resumed = false;
 300
 301   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 302      THREAD_STOPPED states are different from EXECUTING.  When the
 303      thread is stopped internally while handling an internal event,
 304      like a software single-step breakpoint, EXECUTING will be false,
 305      but STATE will still be THREAD_RUNNING.  */
 306   enum thread_state state = THREAD_STOPPED;
 307
 308   /* State of GDB control of inferior thread execution.
 309      See `struct thread_control_state'.  */
 310   thread_control_state control;
 311
 312   /* State of inferior thread to restore after GDB is done with an inferior
 313      call.  See `struct thread_suspend_state'.  */
 314   thread_suspend_state suspend;
 315
 316   int current_line = 0;
 317   struct symtab *current_symtab = NULL;
 318
 319   /* Internal stepping state.  */
 320
 321   /* Record the pc of the thread the last time it was resumed.  (It
 322      can't be done on stop as the PC may change since the last stop,
 323      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 324      by proceed and keep_going, and among other things, it's used in
 325      adjust_pc_after_break to distinguish a hardware single-step
 326      SIGTRAP from a breakpoint SIGTRAP.  */
 327   CORE_ADDR prev_pc = 0;
 328
 329   /* Did we set the thread stepping a breakpoint instruction?  This is
 330      used in conjunction with PREV_PC to decide whether to adjust the
 331      PC.  */
 332   int stepped_breakpoint = 0;
 333
 334   /* Should we step over breakpoint next time keep_going is called?  */
 335   int stepping_over_breakpoint = 0;
 336
 337   /* Should we step over a watchpoint next time keep_going is called?
 338      This is needed on targets with non-continuable, non-steppable
 339      watchpoints.  */
 340   int stepping_over_watchpoint = 0;
 341
 342   /* Set to TRUE if we should finish single-stepping over a breakpoint
 343      after hitting the current step-resume breakpoint.  The context here
 344      is that GDB is to do `next' or `step' while signal arrives.
 345      When stepping over a breakpoint and signal arrives, GDB will attempt
 346      to skip signal handler, so it inserts a step_resume_breakpoint at the
 347      signal return address, and resume inferior.
 348      step_after_step_resume_breakpoint is set to TRUE at this moment in
 349      order to keep GDB in mind that there is still a breakpoint to step over
 350      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 351   int step_after_step_resume_breakpoint = 0;
 352
 353   /* Pointer to the state machine manager object that handles what is
 354      left to do for the thread's execution command after the target
 355      stops.  Several execution commands use it.  */
 356   struct thread_fsm *thread_fsm = NULL;
 357
 358   /* This is used to remember when a fork or vfork event was caught by
 359      a catchpoint, and thus the event is to be followed at the next
 360      resume of the thread, and not immediately.  */
 361   struct target_waitstatus pending_follow;
 362
 363   /* True if this thread has been explicitly requested to stop.  */
 364   int stop_requested = 0;
 365
 366   /* The initiating frame of a nexting operation, used for deciding
 367      which exceptions to intercept.  If it is null_frame_id no
 368      bp_longjmp or bp_exception but longjmp has been caught just for
 369      bp_longjmp_call_dummy.  */
 370   struct frame_id initiating_frame = null_frame_id;
 371
 372   /* Private data used by the target vector implementation.  */
 373   std::unique_ptr<private_thread_info> priv;
 374
 375   /* Branch trace information for this thread.  */
 376   struct btrace_thread_info btrace {};
 377
 378   /* Flag which indicates that the stack temporaries should be stored while
 379      evaluating expressions.  */
 380   bool stack_temporaries_enabled = false;
 381
 382   /* Values that are stored as temporaries on stack while evaluating
 383      expressions.  */
 384   std::vector<struct value *> stack_temporaries;
 385
 386   /* Step-over chain.  A thread is in the step-over queue if these are
 387      non-NULL.  If only a single thread is in the chain, then these
 388      fields point to self.  */
 389   struct thread_info *step_over_prev = NULL;
 390   struct thread_info *step_over_next = NULL;
 391 };
 392
 393 /* A gdb::ref_ptr pointer to a thread_info.  */
 394
 395 using thread_info_ref
 396   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 397
 398 /* A gdb::ref_ptr pointer to an inferior.  This would ideally be in
 399    inferior.h, but it can't due to header dependencies (inferior.h
 400    includes gdbthread.h).  */
 401
 402 using inferior_ref
 403   = gdb::ref_ptr<struct inferior, refcounted_object_ref_policy>;
 404
 405 /* Create an empty thread list, or empty the existing one.  */
 406 extern void init_thread_list (void);
 407
 408 /* Add a thread to the thread list, print a message
 409    that a new thread is found, and return the pointer to
 410    the new thread.  Caller my use this pointer to
 411    initialize the private thread data.  */
 412 extern struct thread_info *add_thread (process_stratum_target *targ,
 413                                        ptid_t ptid);
 414
 415 /* Same as add_thread, but does not print a message about new
 416    thread.  */
 417 extern struct thread_info *add_thread_silent (process_stratum_target *targ,
 418                                               ptid_t ptid);
 419
 420 /* Same as add_thread, and sets the private info.  */
 421 extern struct thread_info *add_thread_with_info (process_stratum_target *targ,
 422                                                  ptid_t ptid,
 423                                                  private_thread_info *);
 424
 425 /* Delete thread THREAD and notify of thread exit.  If the thread is
 426    currently not deletable, don't actually delete it but still tag it
 427    as exited and do the notification.  */
 428 extern void delete_thread (struct thread_info *thread);
 429
 430 /* Like delete_thread, but be quiet about it.  Used when the process
 431    this thread belonged to has already exited, for example.  */
 432 extern void delete_thread_silent (struct thread_info *thread);
 433
 434 /* Delete a step_resume_breakpoint from the thread database.  */
 435 extern void delete_step_resume_breakpoint (struct thread_info *);
 436
 437 /* Delete an exception_resume_breakpoint from the thread database.  */
 438 extern void delete_exception_resume_breakpoint (struct thread_info *);
 439
 440 /* Delete the single-step breakpoints of thread TP, if any.  */
 441 extern void delete_single_step_breakpoints (struct thread_info *tp);
 442
 443 /* Check if the thread has software single stepping breakpoints
 444    set.  */
 445 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 446
 447 /* Check whether the thread has software single stepping breakpoints
 448    set at PC.  */
 449 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 450                                                    const address_space *aspace,
 451                                                    CORE_ADDR addr);
 452
 453 /* Returns whether to show inferior-qualified thread IDs, or plain
 454    thread numbers.  Inferior-qualified IDs are shown whenever we have
 455    multiple inferiors, or the only inferior left has number > 1.  */
 456 extern int show_inferior_qualified_tids (void);
 457
 458 /* Return a string version of THR's thread ID.  If there are multiple
 459    inferiors, then this prints the inferior-qualifier form, otherwise
 460    it only prints the thread number.  The result is stored in a
 461    circular static buffer, NUMCELLS deep.  */
 462 const char *print_thread_id (struct thread_info *thr);
 463
 464 /* Boolean test for an already-known ptid.  */
 465 extern bool in_thread_list (process_stratum_target *targ, ptid_t ptid);
 466
 467 /* Boolean test for an already-known global thread id (GDB's homegrown
 468    global id, not the system's).  */
 469 extern int valid_global_thread_id (int global_id);
 470
 471 /* Find (non-exited) thread PTID of inferior INF.  */
 472 extern thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 473
 474 /* Search function to lookup a (non-exited) thread by 'ptid'.  */
 475 extern struct thread_info *find_thread_ptid (process_stratum_target *targ,
 476                                              ptid_t ptid);
 477
 478 /* Search function to lookup a (non-exited) thread by 'ptid'.  Only
 479    searches in threads of INF.  */
 480 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 481
 482 /* Find thread by GDB global thread ID.  */
 483 struct thread_info *find_thread_global_id (int global_id);
 484
 485 /* Find thread by thread library specific handle in inferior INF.  */
 486 struct thread_info *find_thread_by_handle
 487   (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
 488
 489 /* Finds the first thread of the specified inferior.  */
 490 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 491
 492 /* Returns any thread of inferior INF, giving preference to the
 493    current thread.  */
 494 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 495
 496 /* Returns any non-exited thread of inferior INF, giving preference to
 497    the current thread, and to not executing threads.  */
 498 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 499
 500 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 501 void thread_change_ptid (process_stratum_target *targ,
 502                          ptid_t old_ptid, ptid_t new_ptid);
 503
 504 /* Iterator function to call a user-provided callback function
 505    once for each known thread.  */
 506 typedef int (*thread_callback_func) (struct thread_info *, void *);
 507 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 508
 509 /* Pull in the internals of the inferiors/threads ranges and
 510    iterators.  Must be done after struct thread_info is defined.  */
 511 #include "thread-iter.h"
 512
 513 /* Return a range that can be used to walk over threads, with
 514    range-for.
 515
 516    Used like this, it walks over all threads of all inferiors of all
 517    targets:
 518
 519        for (thread_info *thr : all_threads ())
 520          { .... }
 521
 522    FILTER_PTID can be used to filter out threads that don't match.
 523    FILTER_PTID can be:
 524
 525    - minus_one_ptid, meaning walk all threads of all inferiors of
 526      PROC_TARGET.  If PROC_TARGET is NULL, then of all targets.
 527
 528    - A process ptid, in which case walk all threads of the specified
 529      process.  PROC_TARGET must be non-NULL in this case.
 530
 531    - A thread ptid, in which case walk that thread only.  PROC_TARGET
 532      must be non-NULL in this case.
 533 */
 534
 535 inline all_matching_threads_range
 536 all_threads (process_stratum_target *proc_target = nullptr,
 537              ptid_t filter_ptid = minus_one_ptid)
 538 {
 539   return all_matching_threads_range (proc_target, filter_ptid);
 540 }
 541
 542 /* Return a range that can be used to walk over all non-exited threads
 543    of all inferiors, with range-for.  Arguments are like all_threads
 544    above.  */
 545
 546 inline all_non_exited_threads_range
 547 all_non_exited_threads (process_stratum_target *proc_target = nullptr,
 548                         ptid_t filter_ptid = minus_one_ptid)
 549 {
 550   return all_non_exited_threads_range (proc_target, filter_ptid);
 551 }
 552
 553 /* Return a range that can be used to walk over all threads of all
 554    inferiors, with range-for, safely.  I.e., it is safe to delete the
 555    currently-iterated thread.  When combined with range-for, this
 556    allow convenient patterns like this:
 557
 558      for (thread_info *t : all_threads_safe ())
 559        if (some_condition ())
 560          delete f;
 561 */
 562
 563 inline all_threads_safe_range
 564 all_threads_safe ()
 565 {
 566   return {};
 567 }
 568
 569 extern int thread_count (process_stratum_target *proc_target);
 570
 571 /* Return true if we have any thread in any inferior.  */
 572 extern bool any_thread_p ();
 573
 574 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 575 extern void switch_to_thread (struct thread_info *thr);
 576
 577 /* Switch context to no thread selected.  */
 578 extern void switch_to_no_thread ();
 579
 580 /* Switch from one thread to another.  Does not read registers.  */
 581 extern void switch_to_thread_no_regs (struct thread_info *thread);
 582
 583 /* Marks or clears thread(s) PTID of TARG as resumed.  If PTID is
 584    MINUS_ONE_PTID, applies to all threads of TARG.  If
 585    ptid_is_pid(PTID) is true, applies to all threads of the process
 586    pointed at by {TARG,PTID}.  */
 587 extern void set_resumed (process_stratum_target *targ,
 588                          ptid_t ptid, bool resumed);
 589
 590 /* Marks thread PTID of TARG as running, or as stopped.  If PTID is
 591    minus_one_ptid, marks all threads of TARG.  */
 592 extern void set_running (process_stratum_target *targ,
 593                          ptid_t ptid, bool running);
 594
 595 /* Marks or clears thread(s) PTID of TARG as having been requested to
 596    stop.  If PTID is MINUS_ONE_PTID, applies to all threads of TARG.
 597    If ptid_is_pid(PTID) is true, applies to all threads of the process
 598    pointed at by {TARG, PTID}.  If STOP, then the
 599    THREAD_STOP_REQUESTED observer is called with PTID as argument.  */
 600 extern void set_stop_requested (process_stratum_target *targ,
 601                                 ptid_t ptid, bool stop);
 602
 603 /* Marks thread PTID of TARG as executing, or not.  If PTID is
 604    minus_one_ptid, marks all threads of TARG.
 605
 606    Note that this is different from the running state.  See the
 607    description of state and executing fields of struct
 608    thread_info.  */
 609 extern void set_executing (process_stratum_target *targ,
 610                            ptid_t ptid, bool executing);
 611
 612 /* True if any (known or unknown) thread of TARG is or may be
 613    executing.  */
 614 extern bool threads_are_executing (process_stratum_target *targ);
 615
 616 /* Merge the executing property of thread PTID of TARG over to its
 617    thread state property (frontend running/stopped view).
 618
 619    "not executing" -> "stopped"
 620    "executing"     -> "running"
 621    "exited"        -> "exited"
 622
 623    If PTID is minus_one_ptid, go over all threads of TARG.
 624
 625    Notifications are only emitted if the thread state did change.  */
 626 extern void finish_thread_state (process_stratum_target *targ, ptid_t ptid);
 627
 628 /* Calls finish_thread_state on scope exit, unless release() is called
 629    to disengage.  */
 630 using scoped_finish_thread_state
 631   = FORWARD_SCOPE_EXIT (finish_thread_state);
 632
 633 /* Commands with a prefix of `thread'.  */
 634 extern struct cmd_list_element *thread_cmd_list;
 635
 636 extern void thread_command (const char *tidstr, int from_tty);
 637
 638 /* Print notices on thread events (attach, detach, etc.), set with
 639    `set print thread-events'.  */
 640 extern bool print_thread_events;
 641
 642 /* Prints the list of threads and their details on UIOUT.  If
 643    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 644    print threads whose ID is included in the list.  If PID is not -1,
 645    only print threads from the process PID.  Otherwise, threads from
 646    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 647    NULL and PID is not -1, then the thread is printed if it belongs to
 648    the specified process.  Otherwise, an error is raised.  */
 649 extern void print_thread_info (struct ui_out *uiout,
 650                                const char *requested_threads,
 651                                int pid);
 652
 653 /* Save/restore current inferior/thread/frame.  */
 654
 655 class scoped_restore_current_thread
 656 {
 657 public:
 658   scoped_restore_current_thread ();
 659   ~scoped_restore_current_thread ();
 660
 661   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 662
 663   /* Cancel restoring on scope exit.  */
 664   void dont_restore () { m_dont_restore = true; }
 665
 666 private:
 667   void restore ();
 668
 669   bool m_dont_restore = false;
 670   thread_info_ref m_thread;
 671   inferior_ref m_inf;
 672
 673   frame_id m_selected_frame_id;
 674   int m_selected_frame_level;
 675   bool m_was_stopped;
 676 };
 677
 678 /* Returns a pointer into the thread_info corresponding to
 679    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 680 extern struct thread_info* inferior_thread (void);
 681
 682 extern void update_thread_list (void);
 683
 684 /* Delete any thread the target says is no longer alive.  */
 685
 686 extern void prune_threads (void);
 687
 688 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 689    does not consult the target about whether the thread is alive right
 690    now.  */
 691 extern void delete_exited_threads (void);
 692
 693 /* Return true if PC is in the stepping range of THREAD.  */
 694
 695 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 696
 697 /* Enable storing stack temporaries for thread THR and disable and
 698    clear the stack temporaries on destruction.  Holds a strong
 699    reference to THR.  */
 700
 701 class enable_thread_stack_temporaries
 702 {
 703 public:
 704
 705   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 706     : m_thr (thr)
 707   {
 708     gdb_assert (m_thr != NULL);
 709
 710     m_thr->incref ();
 711
 712     m_thr->stack_temporaries_enabled = true;
 713     m_thr->stack_temporaries.clear ();
 714   }
 715
 716   ~enable_thread_stack_temporaries ()
 717   {
 718     m_thr->stack_temporaries_enabled = false;
 719     m_thr->stack_temporaries.clear ();
 720
 721     m_thr->decref ();
 722   }
 723
 724   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 725
 726 private:
 727
 728   struct thread_info *m_thr;
 729 };
 730
 731 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 732
 733 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 734
 735 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 736
 737 extern bool value_in_thread_stack_temporaries (struct value *,
 738                                                struct thread_info *thr);
 739
 740 /* Add TP to the end of its inferior's pending step-over chain.  */
 741
 742 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 743
 744 /* Remove TP from its inferior's pending step-over chain.  */
 745
 746 extern void thread_step_over_chain_remove (struct thread_info *tp);
 747
 748 /* Return the next thread in the step-over chain starting at TP.  NULL
 749    if TP is the last entry in the chain.  */
 750
 751 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 752
 753 /* Return true if TP is in the step-over chain.  */
 754
 755 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 756
 757 /* Cancel any ongoing execution command.  */
 758
 759 extern void thread_cancel_execution_command (struct thread_info *thr);
 760
 761 /* Check whether it makes sense to access a register of the current
 762    thread at this point.  If not, throw an error (e.g., the thread is
 763    executing).  */
 764 extern void validate_registers_access (void);
 765
 766 /* Check whether it makes sense to access a register of THREAD at this point.
 767    Returns true if registers may be accessed; false otherwise.  */
 768 extern bool can_access_registers_thread (struct thread_info *thread);
 769
 770 /* Returns whether to show which thread hit the breakpoint, received a
 771    signal, etc. and ended up causing a user-visible stop.  This is
 772    true iff we ever detected multiple threads.  */
 773 extern int show_thread_that_caused_stop (void);
 774
 775 /* Print the message for a thread or/and frame selected.  */
 776 extern void print_selected_thread_frame (struct ui_out *uiout,
 777                                          user_selected_what selection);
 778
 779 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 780    Selects thread THR.  TIDSTR is the original string the thread ID
 781    was parsed from.  This is used in the error message if THR is not
 782    alive anymore.  */
 783 extern void thread_select (const char *tidstr, class thread_info *thr);
 784
 785 #endif /* GDBTHREAD_H */