gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2021 Free Software Foundation, Inc.
   3    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   4
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GDBTHREAD_H
  22 #define GDBTHREAD_H
  23
  24 struct symtab;
  25
  26 #include "breakpoint.h"
  27 #include "frame.h"
  28 #include "ui-out.h"
  29 #include "btrace.h"
  30 #include "target/waitstatus.h"
  31 #include "cli/cli-utils.h"
  32 #include "gdbsupport/refcounted-object.h"
  33 #include "gdbsupport/common-gdbthread.h"
  34 #include "gdbsupport/forward-scope-exit.h"
  35 #include "displaced-stepping.h"
  36
  37 struct inferior;
  38 struct process_stratum_target;
  39
  40 /* Frontend view of the thread state.  Possible extensions: stepping,
  41    finishing, until(ling),...
  42
  43    NOTE: Since the thread state is not a boolean, most times, you do
  44    not want to check it with negation.  If you really want to check if
  45    the thread is stopped,
  46
  47     use (good):
  48
  49      if (tp->state == THREAD_STOPPED)
  50
  51     instead of (bad):
  52
  53      if (tp->state != THREAD_RUNNING)
  54
  55    The latter is also true for exited threads, most likely not what
  56    you want.  */
  57 enum thread_state
  58 {
  59   /* In the frontend's perpective, the thread is stopped.  */
  60   THREAD_STOPPED,
  61
  62   /* In the frontend's perpective, the thread is running.  */
  63   THREAD_RUNNING,
  64
  65   /* The thread is listed, but known to have exited.  We keep it
  66      listed (but not visible) until it's safe to delete it.  */
  67   THREAD_EXITED,
  68 };
  69
  70 /* STEP_OVER_ALL means step over all subroutine calls.
  71    STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
  72    STEP_OVER_NONE means don't step over any subroutine calls.  */
  73
  74 enum step_over_calls_kind
  75   {
  76     STEP_OVER_NONE,
  77     STEP_OVER_ALL,
  78     STEP_OVER_UNDEBUGGABLE
  79   };
  80
  81 /* Inferior thread specific part of `struct infcall_control_state'.
  82
  83    Inferior process counterpart is `struct inferior_control_state'.  */
  84
  85 struct thread_control_state
  86 {
  87   /* User/external stepping state.  */
  88
  89   /* Step-resume or longjmp-resume breakpoint.  */
  90   struct breakpoint *step_resume_breakpoint = nullptr;
  91
  92   /* Exception-resume breakpoint.  */
  93   struct breakpoint *exception_resume_breakpoint = nullptr;
  94
  95   /* Breakpoints used for software single stepping.  Plural, because
  96      it may have multiple locations.  E.g., if stepping over a
  97      conditional branch instruction we can't decode the condition for,
  98      we'll need to put a breakpoint at the branch destination, and
  99      another at the instruction after the branch.  */
 100   struct breakpoint *single_step_breakpoints = nullptr;
 101
 102   /* Range to single step within.
 103
 104      If this is nonzero, respond to a single-step signal by continuing
 105      to step if the pc is in this range.
 106
 107      If step_range_start and step_range_end are both 1, it means to
 108      step for a single instruction (FIXME: it might clean up
 109      wait_for_inferior in a minor way if this were changed to the
 110      address of the instruction and that address plus one.  But maybe
 111      not).  */
 112   CORE_ADDR step_range_start = 0;       /* Inclusive */
 113   CORE_ADDR step_range_end = 0;         /* Exclusive */
 114
 115   /* Function the thread was in as of last it started stepping.  */
 116   struct symbol *step_start_function = nullptr;
 117
 118   /* If GDB issues a target step request, and this is nonzero, the
 119      target should single-step this thread once, and then continue
 120      single-stepping it without GDB core involvement as long as the
 121      thread stops in the step range above.  If this is zero, the
 122      target should ignore the step range, and only issue one single
 123      step.  */
 124   int may_range_step = 0;
 125
 126   /* Stack frame address as of when stepping command was issued.
 127      This is how we know when we step into a subroutine call, and how
 128      to set the frame for the breakpoint used to step out.  */
 129   struct frame_id step_frame_id {};
 130
 131   /* Similarly, the frame ID of the underlying stack frame (skipping
 132      any inlined frames).  */
 133   struct frame_id step_stack_frame_id {};
 134
 135   /* True if the the thread is presently stepping over a breakpoint or
 136      a watchpoint, either with an inline step over or a displaced (out
 137      of line) step, and we're now expecting it to report a trap for
 138      the finished single step.  */
 139   int trap_expected = 0;
 140
 141   /* Nonzero if the thread is being proceeded for a "finish" command
 142      or a similar situation when return value should be printed.  */
 143   int proceed_to_finish = 0;
 144
 145   /* Nonzero if the thread is being proceeded for an inferior function
 146      call.  */
 147   int in_infcall = 0;
 148
 149   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 150
 151   /* Nonzero if stopped due to a step command.  */
 152   int stop_step = 0;
 153
 154   /* Chain containing status of breakpoint(s) the thread stopped
 155      at.  */
 156   bpstat stop_bpstat = nullptr;
 157
 158   /* Whether the command that started the thread was a stepping
 159      command.  This is used to decide whether "set scheduler-locking
 160      step" behaves like "on" or "off".  */
 161   int stepping_command = 0;
 162 };
 163
 164 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 165
 166 struct thread_suspend_state
 167 {
 168   /* Last signal that the inferior received (why it stopped).  When
 169      the thread is resumed, this signal is delivered.  Note: the
 170      target should not check whether the signal is in pass state,
 171      because the signal may have been explicitly passed with the
 172      "signal" command, which overrides "handle nopass".  If the signal
 173      should be suppressed, the core will take care of clearing this
 174      before the target is resumed.  */
 175   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 176
 177   /* The reason the thread last stopped, if we need to track it
 178      (breakpoint, watchpoint, etc.)  */
 179   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 180
 181   /* The waitstatus for this thread's last event.  */
 182   struct target_waitstatus waitstatus {};
 183   /* If true WAITSTATUS hasn't been handled yet.  */
 184   int waitstatus_pending_p = 0;
 185
 186   /* Record the pc of the thread the last time it stopped.  (This is
 187      not the current thread's PC as that may have changed since the
 188      last stop, e.g., "return" command, or "p $pc = 0xf000").
 189
 190      - If the thread's PC has not changed since the thread last
 191        stopped, then proceed skips a breakpoint at the current PC,
 192        otherwise we let the thread run into the breakpoint.
 193
 194      - If the thread has an unprocessed event pending, as indicated by
 195        waitstatus_pending_p, this is used in coordination with
 196        stop_reason: if the thread's PC has changed since the thread
 197        last stopped, a pending breakpoint waitstatus is discarded.
 198
 199      - If the thread is running, this is set to -1, to avoid leaving
 200        it with a stale value, to make it easier to catch bugs.  */
 201   CORE_ADDR stop_pc = 0;
 202 };
 203
 204 /* Base class for target-specific thread data.  */
 205 struct private_thread_info
 206 {
 207   virtual ~private_thread_info () = 0;
 208 };
 209
 210 /* Threads are intrusively refcounted objects.  Being the
 211    user-selected thread is normally considered an implicit strong
 212    reference and is thus not accounted in the refcount, unlike
 213    inferior objects.  This is necessary, because there's no "current
 214    thread" pointer.  Instead the current thread is inferred from the
 215    inferior_ptid global.  However, when GDB needs to remember the
 216    selected thread to later restore it, GDB bumps the thread object's
 217    refcount, to prevent something deleting the thread object before
 218    reverting back (e.g., due to a "kill" command).  If the thread
 219    meanwhile exits before being re-selected, then the thread object is
 220    left listed in the thread list, but marked with state
 221    THREAD_EXITED.  (See scoped_restore_current_thread and
 222    delete_thread).  All other thread references are considered weak
 223    references.  Placing a thread in the thread list is an implicit
 224    strong reference, and is thus not accounted for in the thread's
 225    refcount.  */
 226
 227 class thread_info : public refcounted_object
 228 {
 229 public:
 230   explicit thread_info (inferior *inf, ptid_t ptid);
 231   ~thread_info ();
 232
 233   bool deletable () const;
 234
 235   /* Mark this thread as running and notify observers.  */
 236   void set_running (bool running);
 237
 238   struct thread_info *next = NULL;
 239   ptid_t ptid;                  /* "Actual process id";
 240                                     In fact, this may be overloaded with
 241                                     kernel thread id, etc.  */
 242
 243   /* Each thread has two GDB IDs.
 244
 245      a) The thread ID (Id).  This consists of the pair of:
 246
 247         - the number of the thread's inferior and,
 248
 249         - the thread's thread number in its inferior, aka, the
 250           per-inferior thread number.  This number is unique in the
 251           inferior but not unique between inferiors.
 252
 253      b) The global ID (GId).  This is a a single integer unique
 254         between all inferiors.
 255
 256      E.g.:
 257
 258       (gdb) info threads -gid
 259         Id    GId   Target Id   Frame
 260       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 261         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 262         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 263         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 264         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 265         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 266
 267      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 268      thread has its own unique global ID.  */
 269
 270   /* The thread's global GDB thread number.  This is exposed to MI,
 271      Python/Scheme, visible with "info threads -gid", and is also what
 272      the $_gthread convenience variable is bound to.  */
 273   int global_num;
 274
 275   /* The per-inferior thread number.  This is unique in the inferior
 276      the thread belongs to, but not unique between inferiors.  This is
 277      what the $_thread convenience variable is bound to.  */
 278   int per_inf_num;
 279
 280   /* The inferior this thread belongs to.  */
 281   struct inferior *inf;
 282
 283   /* The name of the thread, as specified by the user.  This is NULL
 284      if the thread does not have a user-given name.  */
 285   char *name = NULL;
 286
 287   /* True means the thread is executing.  Note: this is different
 288      from saying that there is an active target and we are stopped at
 289      a breakpoint, for instance.  This is a real indicator whether the
 290      thread is off and running.  */
 291   bool executing = false;
 292
 293   /* True if this thread is resumed from infrun's perspective.
 294      Note that a thread can be marked both as not-executing and
 295      resumed at the same time.  This happens if we try to resume a
 296      thread that has a wait status pending.  We shouldn't let the
 297      thread really run until that wait status has been processed, but
 298      we should not process that wait status if we didn't try to let
 299      the thread run.  */
 300   bool resumed = false;
 301
 302   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 303      THREAD_STOPPED states are different from EXECUTING.  When the
 304      thread is stopped internally while handling an internal event,
 305      like a software single-step breakpoint, EXECUTING will be false,
 306      but STATE will still be THREAD_RUNNING.  */
 307   enum thread_state state = THREAD_STOPPED;
 308
 309   /* State of GDB control of inferior thread execution.
 310      See `struct thread_control_state'.  */
 311   thread_control_state control;
 312
 313   /* State of inferior thread to restore after GDB is done with an inferior
 314      call.  See `struct thread_suspend_state'.  */
 315   thread_suspend_state suspend;
 316
 317   int current_line = 0;
 318   struct symtab *current_symtab = NULL;
 319
 320   /* Internal stepping state.  */
 321
 322   /* Record the pc of the thread the last time it was resumed.  (It
 323      can't be done on stop as the PC may change since the last stop,
 324      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 325      by proceed and keep_going, and among other things, it's used in
 326      adjust_pc_after_break to distinguish a hardware single-step
 327      SIGTRAP from a breakpoint SIGTRAP.  */
 328   CORE_ADDR prev_pc = 0;
 329
 330   /* Did we set the thread stepping a breakpoint instruction?  This is
 331      used in conjunction with PREV_PC to decide whether to adjust the
 332      PC.  */
 333   int stepped_breakpoint = 0;
 334
 335   /* Should we step over breakpoint next time keep_going is called?  */
 336   int stepping_over_breakpoint = 0;
 337
 338   /* Should we step over a watchpoint next time keep_going is called?
 339      This is needed on targets with non-continuable, non-steppable
 340      watchpoints.  */
 341   int stepping_over_watchpoint = 0;
 342
 343   /* Set to TRUE if we should finish single-stepping over a breakpoint
 344      after hitting the current step-resume breakpoint.  The context here
 345      is that GDB is to do `next' or `step' while signal arrives.
 346      When stepping over a breakpoint and signal arrives, GDB will attempt
 347      to skip signal handler, so it inserts a step_resume_breakpoint at the
 348      signal return address, and resume inferior.
 349      step_after_step_resume_breakpoint is set to TRUE at this moment in
 350      order to keep GDB in mind that there is still a breakpoint to step over
 351      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 352   int step_after_step_resume_breakpoint = 0;
 353
 354   /* Pointer to the state machine manager object that handles what is
 355      left to do for the thread's execution command after the target
 356      stops.  Several execution commands use it.  */
 357   struct thread_fsm *thread_fsm = NULL;
 358
 359   /* This is used to remember when a fork or vfork event was caught by
 360      a catchpoint, and thus the event is to be followed at the next
 361      resume of the thread, and not immediately.  */
 362   struct target_waitstatus pending_follow;
 363
 364   /* True if this thread has been explicitly requested to stop.  */
 365   int stop_requested = 0;
 366
 367   /* The initiating frame of a nexting operation, used for deciding
 368      which exceptions to intercept.  If it is null_frame_id no
 369      bp_longjmp or bp_exception but longjmp has been caught just for
 370      bp_longjmp_call_dummy.  */
 371   struct frame_id initiating_frame = null_frame_id;
 372
 373   /* Private data used by the target vector implementation.  */
 374   std::unique_ptr<private_thread_info> priv;
 375
 376   /* Branch trace information for this thread.  */
 377   struct btrace_thread_info btrace {};
 378
 379   /* Flag which indicates that the stack temporaries should be stored while
 380      evaluating expressions.  */
 381   bool stack_temporaries_enabled = false;
 382
 383   /* Values that are stored as temporaries on stack while evaluating
 384      expressions.  */
 385   std::vector<struct value *> stack_temporaries;
 386
 387   /* Step-over chain.  A thread is in the step-over queue if these are
 388      non-NULL.  If only a single thread is in the chain, then these
 389      fields point to self.  */
 390   struct thread_info *step_over_prev = NULL;
 391   struct thread_info *step_over_next = NULL;
 392
 393   /* Displaced-step state for this thread.  */
 394   displaced_step_thread_state displaced_step_state;
 395 };
 396
 397 /* A gdb::ref_ptr pointer to a thread_info.  */
 398
 399 using thread_info_ref
 400   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 401
 402 /* A gdb::ref_ptr pointer to an inferior.  This would ideally be in
 403    inferior.h, but it can't due to header dependencies (inferior.h
 404    includes gdbthread.h).  */
 405
 406 using inferior_ref
 407   = gdb::ref_ptr<struct inferior, refcounted_object_ref_policy>;
 408
 409 /* Create an empty thread list, or empty the existing one.  */
 410 extern void init_thread_list (void);
 411
 412 /* Add a thread to the thread list, print a message
 413    that a new thread is found, and return the pointer to
 414    the new thread.  Caller my use this pointer to
 415    initialize the private thread data.  */
 416 extern struct thread_info *add_thread (process_stratum_target *targ,
 417                                        ptid_t ptid);
 418
 419 /* Same as add_thread, but does not print a message about new
 420    thread.  */
 421 extern struct thread_info *add_thread_silent (process_stratum_target *targ,
 422                                               ptid_t ptid);
 423
 424 /* Same as add_thread, and sets the private info.  */
 425 extern struct thread_info *add_thread_with_info (process_stratum_target *targ,
 426                                                  ptid_t ptid,
 427                                                  private_thread_info *);
 428
 429 /* Delete thread THREAD and notify of thread exit.  If the thread is
 430    currently not deletable, don't actually delete it but still tag it
 431    as exited and do the notification.  */
 432 extern void delete_thread (struct thread_info *thread);
 433
 434 /* Like delete_thread, but be quiet about it.  Used when the process
 435    this thread belonged to has already exited, for example.  */
 436 extern void delete_thread_silent (struct thread_info *thread);
 437
 438 /* Delete a step_resume_breakpoint from the thread database.  */
 439 extern void delete_step_resume_breakpoint (struct thread_info *);
 440
 441 /* Delete an exception_resume_breakpoint from the thread database.  */
 442 extern void delete_exception_resume_breakpoint (struct thread_info *);
 443
 444 /* Delete the single-step breakpoints of thread TP, if any.  */
 445 extern void delete_single_step_breakpoints (struct thread_info *tp);
 446
 447 /* Check if the thread has software single stepping breakpoints
 448    set.  */
 449 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 450
 451 /* Check whether the thread has software single stepping breakpoints
 452    set at PC.  */
 453 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 454                                                    const address_space *aspace,
 455                                                    CORE_ADDR addr);
 456
 457 /* Returns whether to show inferior-qualified thread IDs, or plain
 458    thread numbers.  Inferior-qualified IDs are shown whenever we have
 459    multiple inferiors, or the only inferior left has number > 1.  */
 460 extern int show_inferior_qualified_tids (void);
 461
 462 /* Return a string version of THR's thread ID.  If there are multiple
 463    inferiors, then this prints the inferior-qualifier form, otherwise
 464    it only prints the thread number.  The result is stored in a
 465    circular static buffer, NUMCELLS deep.  */
 466 const char *print_thread_id (struct thread_info *thr);
 467
 468 /* Boolean test for an already-known ptid.  */
 469 extern bool in_thread_list (process_stratum_target *targ, ptid_t ptid);
 470
 471 /* Boolean test for an already-known global thread id (GDB's homegrown
 472    global id, not the system's).  */
 473 extern int valid_global_thread_id (int global_id);
 474
 475 /* Find (non-exited) thread PTID of inferior INF.  */
 476 extern thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 477
 478 /* Search function to lookup a (non-exited) thread by 'ptid'.  */
 479 extern struct thread_info *find_thread_ptid (process_stratum_target *targ,
 480                                              ptid_t ptid);
 481
 482 /* Search function to lookup a (non-exited) thread by 'ptid'.  Only
 483    searches in threads of INF.  */
 484 extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
 485
 486 /* Find thread by GDB global thread ID.  */
 487 struct thread_info *find_thread_global_id (int global_id);
 488
 489 /* Find thread by thread library specific handle in inferior INF.  */
 490 struct thread_info *find_thread_by_handle
 491   (gdb::array_view<const gdb_byte> handle, struct inferior *inf);
 492
 493 /* Finds the first thread of the specified inferior.  */
 494 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 495
 496 /* Returns any thread of inferior INF, giving preference to the
 497    current thread.  */
 498 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 499
 500 /* Returns any non-exited thread of inferior INF, giving preference to
 501    the current thread, and to not executing threads.  */
 502 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 503
 504 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 505 void thread_change_ptid (process_stratum_target *targ,
 506                          ptid_t old_ptid, ptid_t new_ptid);
 507
 508 /* Iterator function to call a user-provided callback function
 509    once for each known thread.  */
 510 typedef int (*thread_callback_func) (struct thread_info *, void *);
 511 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 512
 513 /* Pull in the internals of the inferiors/threads ranges and
 514    iterators.  Must be done after struct thread_info is defined.  */
 515 #include "thread-iter.h"
 516
 517 /* Return a range that can be used to walk over threads, with
 518    range-for.
 519
 520    Used like this, it walks over all threads of all inferiors of all
 521    targets:
 522
 523        for (thread_info *thr : all_threads ())
 524          { .... }
 525
 526    FILTER_PTID can be used to filter out threads that don't match.
 527    FILTER_PTID can be:
 528
 529    - minus_one_ptid, meaning walk all threads of all inferiors of
 530      PROC_TARGET.  If PROC_TARGET is NULL, then of all targets.
 531
 532    - A process ptid, in which case walk all threads of the specified
 533      process.  PROC_TARGET must be non-NULL in this case.
 534
 535    - A thread ptid, in which case walk that thread only.  PROC_TARGET
 536      must be non-NULL in this case.
 537 */
 538
 539 inline all_matching_threads_range
 540 all_threads (process_stratum_target *proc_target = nullptr,
 541              ptid_t filter_ptid = minus_one_ptid)
 542 {
 543   return all_matching_threads_range (proc_target, filter_ptid);
 544 }
 545
 546 /* Return a range that can be used to walk over all non-exited threads
 547    of all inferiors, with range-for.  Arguments are like all_threads
 548    above.  */
 549
 550 inline all_non_exited_threads_range
 551 all_non_exited_threads (process_stratum_target *proc_target = nullptr,
 552                         ptid_t filter_ptid = minus_one_ptid)
 553 {
 554   return all_non_exited_threads_range (proc_target, filter_ptid);
 555 }
 556
 557 /* Return a range that can be used to walk over all threads of all
 558    inferiors, with range-for, safely.  I.e., it is safe to delete the
 559    currently-iterated thread.  When combined with range-for, this
 560    allow convenient patterns like this:
 561
 562      for (thread_info *t : all_threads_safe ())
 563        if (some_condition ())
 564          delete f;
 565 */
 566
 567 inline all_threads_safe_range
 568 all_threads_safe ()
 569 {
 570   return {};
 571 }
 572
 573 extern int thread_count (process_stratum_target *proc_target);
 574
 575 /* Return true if we have any thread in any inferior.  */
 576 extern bool any_thread_p ();
 577
 578 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 579 extern void switch_to_thread (struct thread_info *thr);
 580
 581 /* Switch context to no thread selected.  */
 582 extern void switch_to_no_thread ();
 583
 584 /* Switch from one thread to another.  Does not read registers.  */
 585 extern void switch_to_thread_no_regs (struct thread_info *thread);
 586
 587 /* Marks or clears thread(s) PTID of TARG as resumed.  If PTID is
 588    MINUS_ONE_PTID, applies to all threads of TARG.  If
 589    ptid_is_pid(PTID) is true, applies to all threads of the process
 590    pointed at by {TARG,PTID}.  */
 591 extern void set_resumed (process_stratum_target *targ,
 592                          ptid_t ptid, bool resumed);
 593
 594 /* Marks thread PTID of TARG as running, or as stopped.  If PTID is
 595    minus_one_ptid, marks all threads of TARG.  */
 596 extern void set_running (process_stratum_target *targ,
 597                          ptid_t ptid, bool running);
 598
 599 /* Marks or clears thread(s) PTID of TARG as having been requested to
 600    stop.  If PTID is MINUS_ONE_PTID, applies to all threads of TARG.
 601    If ptid_is_pid(PTID) is true, applies to all threads of the process
 602    pointed at by {TARG, PTID}.  If STOP, then the
 603    THREAD_STOP_REQUESTED observer is called with PTID as argument.  */
 604 extern void set_stop_requested (process_stratum_target *targ,
 605                                 ptid_t ptid, bool stop);
 606
 607 /* Marks thread PTID of TARG as executing, or not.  If PTID is
 608    minus_one_ptid, marks all threads of TARG.
 609
 610    Note that this is different from the running state.  See the
 611    description of state and executing fields of struct
 612    thread_info.  */
 613 extern void set_executing (process_stratum_target *targ,
 614                            ptid_t ptid, bool executing);
 615
 616 /* True if any (known or unknown) thread of TARG is or may be
 617    executing.  */
 618 extern bool threads_are_executing (process_stratum_target *targ);
 619
 620 /* Merge the executing property of thread PTID of TARG over to its
 621    thread state property (frontend running/stopped view).
 622
 623    "not executing" -> "stopped"
 624    "executing"     -> "running"
 625    "exited"        -> "exited"
 626
 627    If PTID is minus_one_ptid, go over all threads of TARG.
 628
 629    Notifications are only emitted if the thread state did change.  */
 630 extern void finish_thread_state (process_stratum_target *targ, ptid_t ptid);
 631
 632 /* Calls finish_thread_state on scope exit, unless release() is called
 633    to disengage.  */
 634 using scoped_finish_thread_state
 635   = FORWARD_SCOPE_EXIT (finish_thread_state);
 636
 637 /* Commands with a prefix of `thread'.  */
 638 extern struct cmd_list_element *thread_cmd_list;
 639
 640 extern void thread_command (const char *tidstr, int from_tty);
 641
 642 /* Print notices on thread events (attach, detach, etc.), set with
 643    `set print thread-events'.  */
 644 extern bool print_thread_events;
 645
 646 /* Prints the list of threads and their details on UIOUT.  If
 647    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 648    print threads whose ID is included in the list.  If PID is not -1,
 649    only print threads from the process PID.  Otherwise, threads from
 650    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 651    NULL and PID is not -1, then the thread is printed if it belongs to
 652    the specified process.  Otherwise, an error is raised.  */
 653 extern void print_thread_info (struct ui_out *uiout,
 654                                const char *requested_threads,
 655                                int pid);
 656
 657 /* Save/restore current inferior/thread/frame.  */
 658
 659 class scoped_restore_current_thread
 660 {
 661 public:
 662   scoped_restore_current_thread ();
 663   ~scoped_restore_current_thread ();
 664
 665   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 666
 667   /* Cancel restoring on scope exit.  */
 668   void dont_restore () { m_dont_restore = true; }
 669
 670 private:
 671   void restore ();
 672
 673   bool m_dont_restore = false;
 674   thread_info_ref m_thread;
 675   inferior_ref m_inf;
 676
 677   frame_id m_selected_frame_id;
 678   int m_selected_frame_level;
 679   bool m_was_stopped;
 680   /* Save/restore the language as well, because selecting a frame
 681      changes the current language to the frame's language if "set
 682      language auto".  */
 683   enum language m_lang;
 684 };
 685
 686 /* Returns a pointer into the thread_info corresponding to
 687    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 688 extern struct thread_info* inferior_thread (void);
 689
 690 extern void update_thread_list (void);
 691
 692 /* Delete any thread the target says is no longer alive.  */
 693
 694 extern void prune_threads (void);
 695
 696 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 697    does not consult the target about whether the thread is alive right
 698    now.  */
 699 extern void delete_exited_threads (void);
 700
 701 /* Return true if PC is in the stepping range of THREAD.  */
 702
 703 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 704
 705 /* Enable storing stack temporaries for thread THR and disable and
 706    clear the stack temporaries on destruction.  Holds a strong
 707    reference to THR.  */
 708
 709 class enable_thread_stack_temporaries
 710 {
 711 public:
 712
 713   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 714     : m_thr (thread_info_ref::new_reference (thr))
 715   {
 716     m_thr->stack_temporaries_enabled = true;
 717     m_thr->stack_temporaries.clear ();
 718   }
 719
 720   ~enable_thread_stack_temporaries ()
 721   {
 722     m_thr->stack_temporaries_enabled = false;
 723     m_thr->stack_temporaries.clear ();
 724   }
 725
 726   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 727
 728 private:
 729
 730   thread_info_ref m_thr;
 731 };
 732
 733 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 734
 735 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 736
 737 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 738
 739 extern bool value_in_thread_stack_temporaries (struct value *,
 740                                                struct thread_info *thr);
 741
 742 /* Add TP to the end of the global pending step-over chain.  */
 743
 744 extern void global_thread_step_over_chain_enqueue (thread_info *tp);
 745
 746 /* Append the thread step over chain CHAIN_HEAD to the global thread step over
 747    chain. */
 748
 749 extern void global_thread_step_over_chain_enqueue_chain
 750   (thread_info *chain_head);
 751
 752 /* Remove TP from step-over chain LIST_P.  */
 753
 754 extern void thread_step_over_chain_remove (thread_info **list_p,
 755                                            thread_info *tp);
 756
 757 /* Remove TP from the global pending step-over chain.  */
 758
 759 extern void global_thread_step_over_chain_remove (thread_info *tp);
 760
 761 /* Return the thread following TP in the step-over chain whose head is
 762    CHAIN_HEAD.  Return NULL if TP is the last entry in the chain.  */
 763
 764 extern thread_info *thread_step_over_chain_next (thread_info *chain_head,
 765                                                  thread_info *tp);
 766
 767 /* Return the thread following TP in the global step-over chain, or NULL if TP
 768    is the last entry in the chain.  */
 769
 770 extern thread_info *global_thread_step_over_chain_next (thread_info *tp);
 771
 772 /* Return true if TP is in any step-over chain.  */
 773
 774 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 775
 776 /* Return the length of the the step over chain TP is in.
 777
 778    If TP is non-nullptr, the thread must be in a step over chain.
 779    TP may be nullptr, in which case it denotes an empty list, so a length of
 780    0.  */
 781
 782 extern int thread_step_over_chain_length (thread_info *tp);
 783
 784 /* Cancel any ongoing execution command.  */
 785
 786 extern void thread_cancel_execution_command (struct thread_info *thr);
 787
 788 /* Check whether it makes sense to access a register of the current
 789    thread at this point.  If not, throw an error (e.g., the thread is
 790    executing).  */
 791 extern void validate_registers_access (void);
 792
 793 /* Check whether it makes sense to access a register of THREAD at this point.
 794    Returns true if registers may be accessed; false otherwise.  */
 795 extern bool can_access_registers_thread (struct thread_info *thread);
 796
 797 /* Returns whether to show which thread hit the breakpoint, received a
 798    signal, etc. and ended up causing a user-visible stop.  This is
 799    true iff we ever detected multiple threads.  */
 800 extern int show_thread_that_caused_stop (void);
 801
 802 /* Print the message for a thread or/and frame selected.  */
 803 extern void print_selected_thread_frame (struct ui_out *uiout,
 804                                          user_selected_what selection);
 805
 806 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 807    Selects thread THR.  TIDSTR is the original string the thread ID
 808    was parsed from.  This is used in the error message if THR is not
 809    alive anymore.  */
 810 extern void thread_select (const char *tidstr, class thread_info *thr);
 811
 812 #endif /* GDBTHREAD_H */