gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2018 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 "inferior.h"
  30 #include "btrace.h"
  31 #include "common/vec.h"
  32 #include "target/waitstatus.h"
  33 #include "cli/cli-utils.h"
  34 #include "common/refcounted-object.h"
  35 #include "common-gdbthread.h"
  36
  37 /* Frontend view of the thread state.  Possible extensions: stepping,
  38    finishing, until(ling),...  */
  39 enum thread_state
  40 {
  41   THREAD_STOPPED,
  42   THREAD_RUNNING,
  43   THREAD_EXITED,
  44 };
  45
  46 /* Inferior thread specific part of `struct infcall_control_state'.
  47
  48    Inferior process counterpart is `struct inferior_control_state'.  */
  49
  50 struct thread_control_state
  51 {
  52   /* User/external stepping state.  */
  53
  54   /* Step-resume or longjmp-resume breakpoint.  */
  55   struct breakpoint *step_resume_breakpoint = nullptr;
  56
  57   /* Exception-resume breakpoint.  */
  58   struct breakpoint *exception_resume_breakpoint = nullptr;
  59
  60   /* Breakpoints used for software single stepping.  Plural, because
  61      it may have multiple locations.  E.g., if stepping over a
  62      conditional branch instruction we can't decode the condition for,
  63      we'll need to put a breakpoint at the branch destination, and
  64      another at the instruction after the branch.  */
  65   struct breakpoint *single_step_breakpoints = nullptr;
  66
  67   /* Range to single step within.
  68
  69      If this is nonzero, respond to a single-step signal by continuing
  70      to step if the pc is in this range.
  71
  72      If step_range_start and step_range_end are both 1, it means to
  73      step for a single instruction (FIXME: it might clean up
  74      wait_for_inferior in a minor way if this were changed to the
  75      address of the instruction and that address plus one.  But maybe
  76      not).  */
  77   CORE_ADDR step_range_start = 0;       /* Inclusive */
  78   CORE_ADDR step_range_end = 0;         /* Exclusive */
  79
  80   /* Function the thread was in as of last it started stepping.  */
  81   struct symbol *step_start_function = nullptr;
  82
  83   /* If GDB issues a target step request, and this is nonzero, the
  84      target should single-step this thread once, and then continue
  85      single-stepping it without GDB core involvement as long as the
  86      thread stops in the step range above.  If this is zero, the
  87      target should ignore the step range, and only issue one single
  88      step.  */
  89   int may_range_step = 0;
  90
  91   /* Stack frame address as of when stepping command was issued.
  92      This is how we know when we step into a subroutine call, and how
  93      to set the frame for the breakpoint used to step out.  */
  94   struct frame_id step_frame_id {};
  95
  96   /* Similarly, the frame ID of the underlying stack frame (skipping
  97      any inlined frames).  */
  98   struct frame_id step_stack_frame_id {};
  99
 100   /* Nonzero if we are presently stepping over a breakpoint.
 101
 102      If we hit a breakpoint or watchpoint, and then continue, we need
 103      to single step the current thread with breakpoints disabled, to
 104      avoid hitting the same breakpoint or watchpoint again.  And we
 105      should step just a single thread and keep other threads stopped,
 106      so that other threads don't miss breakpoints while they are
 107      removed.
 108
 109      So, this variable simultaneously means that we need to single
 110      step the current thread, keep other threads stopped, and that
 111      breakpoints should be removed while we step.
 112
 113      This variable is set either:
 114      - in proceed, when we resume inferior on user's explicit request
 115      - in keep_going, if handle_inferior_event decides we need to
 116      step over breakpoint.
 117
 118      The variable is cleared in normal_stop.  The proceed calls
 119      wait_for_inferior, which calls handle_inferior_event in a loop,
 120      and until wait_for_inferior exits, this variable is changed only
 121      by keep_going.  */
 122   int trap_expected = 0;
 123
 124   /* Nonzero if the thread is being proceeded for a "finish" command
 125      or a similar situation when return value should be printed.  */
 126   int proceed_to_finish = 0;
 127
 128   /* Nonzero if the thread is being proceeded for an inferior function
 129      call.  */
 130   int in_infcall = 0;
 131
 132   enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
 133
 134   /* Nonzero if stopped due to a step command.  */
 135   int stop_step = 0;
 136
 137   /* Chain containing status of breakpoint(s) the thread stopped
 138      at.  */
 139   bpstat stop_bpstat = nullptr;
 140
 141   /* Whether the command that started the thread was a stepping
 142      command.  This is used to decide whether "set scheduler-locking
 143      step" behaves like "on" or "off".  */
 144   int stepping_command = 0;
 145 };
 146
 147 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 148
 149 struct thread_suspend_state
 150 {
 151   /* Last signal that the inferior received (why it stopped).  When
 152      the thread is resumed, this signal is delivered.  Note: the
 153      target should not check whether the signal is in pass state,
 154      because the signal may have been explicitly passed with the
 155      "signal" command, which overrides "handle nopass".  If the signal
 156      should be suppressed, the core will take care of clearing this
 157      before the target is resumed.  */
 158   enum gdb_signal stop_signal = GDB_SIGNAL_0;
 159
 160   /* The reason the thread last stopped, if we need to track it
 161      (breakpoint, watchpoint, etc.)  */
 162   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 163
 164   /* The waitstatus for this thread's last event.  */
 165   struct target_waitstatus waitstatus {};
 166   /* If true WAITSTATUS hasn't been handled yet.  */
 167   int waitstatus_pending_p = 0;
 168
 169   /* Record the pc of the thread the last time it stopped.  (This is
 170      not the current thread's PC as that may have changed since the
 171      last stop, e.g., "return" command, or "p $pc = 0xf000").
 172
 173      - If the thread's PC has not changed since the thread last
 174        stopped, then proceed skips a breakpoint at the current PC,
 175        otherwise we let the thread run into the breakpoint.
 176
 177      - If the thread has an unprocessed event pending, as indicated by
 178        waitstatus_pending_p, this is used in coordination with
 179        stop_reason: if the thread's PC has changed since the thread
 180        last stopped, a pending breakpoint waitstatus is discarded.
 181
 182      - If the thread is running, this is set to -1, to avoid leaving
 183        it with a stale value, to make it easier to catch bugs.  */
 184   CORE_ADDR stop_pc = 0;
 185 };
 186
 187 /* Base class for target-specific thread data.  */
 188 struct private_thread_info
 189 {
 190   virtual ~private_thread_info () = 0;
 191 };
 192
 193 /* Threads are intrusively refcounted objects.  Being the
 194    user-selected thread is normally considered an implicit strong
 195    reference and is thus not accounted in the refcount, unlike
 196    inferior objects.  This is necessary, because there's no "current
 197    thread" pointer.  Instead the current thread is inferred from the
 198    inferior_ptid global.  However, when GDB needs to remember the
 199    selected thread to later restore it, GDB bumps the thread object's
 200    refcount, to prevent something deleting the thread object before
 201    reverting back (e.g., due to a "kill" command).  If the thread
 202    meanwhile exits before being re-selected, then the thread object is
 203    left listed in the thread list, but marked with state
 204    THREAD_EXITED.  (See make_cleanup_restore_current_thread and
 205    delete_thread).  All other thread references are considered weak
 206    references.  Placing a thread in the thread list is an implicit
 207    strong reference, and is thus not accounted for in the thread's
 208    refcount.  */
 209
 210 class thread_info : public refcounted_object
 211 {
 212 public:
 213   explicit thread_info (inferior *inf, ptid_t ptid);
 214   ~thread_info ();
 215
 216   bool deletable () const
 217   {
 218     /* If this is the current thread, or there's code out there that
 219        relies on it existing (refcount > 0) we can't delete yet.  */
 220     return (refcount () == 0 && ptid != inferior_ptid);
 221   }
 222
 223   /* Mark this thread as running and notify observers.  */
 224   void set_running (bool running);
 225
 226   struct thread_info *next = NULL;
 227   ptid_t ptid;                  /* "Actual process id";
 228                                     In fact, this may be overloaded with
 229                                     kernel thread id, etc.  */
 230
 231   /* Each thread has two GDB IDs.
 232
 233      a) The thread ID (Id).  This consists of the pair of:
 234
 235         - the number of the thread's inferior and,
 236
 237         - the thread's thread number in its inferior, aka, the
 238           per-inferior thread number.  This number is unique in the
 239           inferior but not unique between inferiors.
 240
 241      b) The global ID (GId).  This is a a single integer unique
 242         between all inferiors.
 243
 244      E.g.:
 245
 246       (gdb) info threads -gid
 247         Id    GId   Target Id   Frame
 248       * 1.1   1     Thread A    0x16a09237 in foo () at foo.c:10
 249         1.2   3     Thread B    0x15ebc6ed in bar () at foo.c:20
 250         1.3   5     Thread C    0x15ebc6ed in bar () at foo.c:20
 251         2.1   2     Thread A    0x16a09237 in foo () at foo.c:10
 252         2.2   4     Thread B    0x15ebc6ed in bar () at foo.c:20
 253         2.3   6     Thread C    0x15ebc6ed in bar () at foo.c:20
 254
 255      Above, both inferiors 1 and 2 have threads numbered 1-3, but each
 256      thread has its own unique global ID.  */
 257
 258   /* The thread's global GDB thread number.  This is exposed to MI,
 259      Python/Scheme, visible with "info threads -gid", and is also what
 260      the $_gthread convenience variable is bound to.  */
 261   int global_num;
 262
 263   /* The per-inferior thread number.  This is unique in the inferior
 264      the thread belongs to, but not unique between inferiors.  This is
 265      what the $_thread convenience variable is bound to.  */
 266   int per_inf_num;
 267
 268   /* The inferior this thread belongs to.  */
 269   struct inferior *inf;
 270
 271   /* The name of the thread, as specified by the user.  This is NULL
 272      if the thread does not have a user-given name.  */
 273   char *name = NULL;
 274
 275   /* Non-zero means the thread is executing.  Note: this is different
 276      from saying that there is an active target and we are stopped at
 277      a breakpoint, for instance.  This is a real indicator whether the
 278      thread is off and running.  */
 279   int executing = 0;
 280
 281   /* Non-zero if this thread is resumed from infrun's perspective.
 282      Note that a thread can be marked both as not-executing and
 283      resumed at the same time.  This happens if we try to resume a
 284      thread that has a wait status pending.  We shouldn't let the
 285      thread really run until that wait status has been processed, but
 286      we should not process that wait status if we didn't try to let
 287      the thread run.  */
 288   int resumed = 0;
 289
 290   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 291      THREAD_STOPPED states are different from EXECUTING.  When the
 292      thread is stopped internally while handling an internal event,
 293      like a software single-step breakpoint, EXECUTING will be false,
 294      but STATE will still be THREAD_RUNNING.  */
 295   enum thread_state state = THREAD_STOPPED;
 296
 297   /* State of GDB control of inferior thread execution.
 298      See `struct thread_control_state'.  */
 299   thread_control_state control;
 300
 301   /* State of inferior thread to restore after GDB is done with an inferior
 302      call.  See `struct thread_suspend_state'.  */
 303   thread_suspend_state suspend;
 304
 305   int current_line = 0;
 306   struct symtab *current_symtab = NULL;
 307
 308   /* Internal stepping state.  */
 309
 310   /* Record the pc of the thread the last time it was resumed.  (It
 311      can't be done on stop as the PC may change since the last stop,
 312      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 313      by proceed and keep_going, and among other things, it's used in
 314      adjust_pc_after_break to distinguish a hardware single-step
 315      SIGTRAP from a breakpoint SIGTRAP.  */
 316   CORE_ADDR prev_pc = 0;
 317
 318   /* Did we set the thread stepping a breakpoint instruction?  This is
 319      used in conjunction with PREV_PC to decide whether to adjust the
 320      PC.  */
 321   int stepped_breakpoint = 0;
 322
 323   /* Should we step over breakpoint next time keep_going is called?  */
 324   int stepping_over_breakpoint = 0;
 325
 326   /* Should we step over a watchpoint next time keep_going is called?
 327      This is needed on targets with non-continuable, non-steppable
 328      watchpoints.  */
 329   int stepping_over_watchpoint = 0;
 330
 331   /* Set to TRUE if we should finish single-stepping over a breakpoint
 332      after hitting the current step-resume breakpoint.  The context here
 333      is that GDB is to do `next' or `step' while signal arrives.
 334      When stepping over a breakpoint and signal arrives, GDB will attempt
 335      to skip signal handler, so it inserts a step_resume_breakpoint at the
 336      signal return address, and resume inferior.
 337      step_after_step_resume_breakpoint is set to TRUE at this moment in
 338      order to keep GDB in mind that there is still a breakpoint to step over
 339      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 340   int step_after_step_resume_breakpoint = 0;
 341
 342   /* Pointer to the state machine manager object that handles what is
 343      left to do for the thread's execution command after the target
 344      stops.  Several execution commands use it.  */
 345   struct thread_fsm *thread_fsm = NULL;
 346
 347   /* This is used to remember when a fork or vfork event was caught by
 348      a catchpoint, and thus the event is to be followed at the next
 349      resume of the thread, and not immediately.  */
 350   struct target_waitstatus pending_follow;
 351
 352   /* True if this thread has been explicitly requested to stop.  */
 353   int stop_requested = 0;
 354
 355   /* The initiating frame of a nexting operation, used for deciding
 356      which exceptions to intercept.  If it is null_frame_id no
 357      bp_longjmp or bp_exception but longjmp has been caught just for
 358      bp_longjmp_call_dummy.  */
 359   struct frame_id initiating_frame = null_frame_id;
 360
 361   /* Private data used by the target vector implementation.  */
 362   std::unique_ptr<private_thread_info> priv;
 363
 364   /* Branch trace information for this thread.  */
 365   struct btrace_thread_info btrace {};
 366
 367   /* Flag which indicates that the stack temporaries should be stored while
 368      evaluating expressions.  */
 369   bool stack_temporaries_enabled = false;
 370
 371   /* Values that are stored as temporaries on stack while evaluating
 372      expressions.  */
 373   std::vector<struct value *> stack_temporaries;
 374
 375   /* Step-over chain.  A thread is in the step-over queue if these are
 376      non-NULL.  If only a single thread is in the chain, then these
 377      fields point to self.  */
 378   struct thread_info *step_over_prev = NULL;
 379   struct thread_info *step_over_next = NULL;
 380 };
 381
 382 /* A gdb::ref_ptr pointer to a thread_info.  */
 383
 384 using thread_info_ref
 385   = gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
 386
 387 /* Create an empty thread list, or empty the existing one.  */
 388 extern void init_thread_list (void);
 389
 390 /* Add a thread to the thread list, print a message
 391    that a new thread is found, and return the pointer to
 392    the new thread.  Caller my use this pointer to
 393    initialize the private thread data.  */
 394 extern struct thread_info *add_thread (ptid_t ptid);
 395
 396 /* Same as add_thread, but does not print a message
 397    about new thread.  */
 398 extern struct thread_info *add_thread_silent (ptid_t ptid);
 399
 400 /* Same as add_thread, and sets the private info.  */
 401 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 402                                                  struct private_thread_info *);
 403
 404 /* Delete an existing thread list entry.  */
 405 extern void delete_thread (struct thread_info *thread);
 406
 407 /* Delete an existing thread list entry, and be quiet about it.  Used
 408    after the process this thread having belonged to having already
 409    exited, for example.  */
 410 extern void delete_thread_silent (struct thread_info *thread);
 411
 412 /* Delete a step_resume_breakpoint from the thread database.  */
 413 extern void delete_step_resume_breakpoint (struct thread_info *);
 414
 415 /* Delete an exception_resume_breakpoint from the thread database.  */
 416 extern void delete_exception_resume_breakpoint (struct thread_info *);
 417
 418 /* Delete the single-step breakpoints of thread TP, if any.  */
 419 extern void delete_single_step_breakpoints (struct thread_info *tp);
 420
 421 /* Check if the thread has software single stepping breakpoints
 422    set.  */
 423 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 424
 425 /* Check whether the thread has software single stepping breakpoints
 426    set at PC.  */
 427 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 428                                                    const address_space *aspace,
 429                                                    CORE_ADDR addr);
 430
 431 /* Returns whether to show inferior-qualified thread IDs, or plain
 432    thread numbers.  Inferior-qualified IDs are shown whenever we have
 433    multiple inferiors, or the only inferior left has number > 1.  */
 434 extern int show_inferior_qualified_tids (void);
 435
 436 /* Return a string version of THR's thread ID.  If there are multiple
 437    inferiors, then this prints the inferior-qualifier form, otherwise
 438    it only prints the thread number.  The result is stored in a
 439    circular static buffer, NUMCELLS deep.  */
 440 const char *print_thread_id (struct thread_info *thr);
 441
 442 /* Boolean test for an already-known ptid.  */
 443 extern int in_thread_list (ptid_t ptid);
 444
 445 /* Boolean test for an already-known global thread id (GDB's homegrown
 446    global id, not the system's).  */
 447 extern int valid_global_thread_id (int global_id);
 448
 449 /* Search function to lookup a thread by 'pid'.  */
 450 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 451
 452 /* Find thread by GDB global thread ID.  */
 453 struct thread_info *find_thread_global_id (int global_id);
 454
 455 /* Find thread by thread library specific handle in inferior INF.  */
 456 struct thread_info *find_thread_by_handle (struct value *thread_handle,
 457                                            struct inferior *inf);
 458
 459 /* Finds the first thread of the specified inferior.  */
 460 extern struct thread_info *first_thread_of_inferior (inferior *inf);
 461
 462 /* Returns any thread of inferior INF, giving preference to the
 463    current thread.  */
 464 extern struct thread_info *any_thread_of_inferior (inferior *inf);
 465
 466 /* Returns any non-exited thread of inferior INF, giving preference to
 467    the current thread, and to not executing threads.  */
 468 extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
 469
 470 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 471 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 472
 473 /* Iterator function to call a user-provided callback function
 474    once for each known thread.  */
 475 typedef int (*thread_callback_func) (struct thread_info *, void *);
 476 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 477
 478 /* Traverse all threads.  */
 479 #define ALL_THREADS(T)                          \
 480   for (T = thread_list; T; T = T->next)         \
 481
 482 /* Traverse over all threads, sorted by inferior.  */
 483 #define ALL_THREADS_BY_INFERIOR(inf, tp) \
 484   ALL_INFERIORS (inf) \
 485     ALL_THREADS (tp) \
 486       if (inf == tp->inf)
 487
 488 /* Traverse all threads, except those that have THREAD_EXITED
 489    state.  */
 490
 491 #define ALL_NON_EXITED_THREADS(T)                               \
 492   for (T = thread_list; T; T = T->next) \
 493     if ((T)->state != THREAD_EXITED)
 494
 495 /* Traverse all threads, including those that have THREAD_EXITED
 496    state.  Allows deleting the currently iterated thread.  */
 497 #define ALL_THREADS_SAFE(T, TMP)        \
 498   for ((T) = thread_list;                       \
 499        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 500        (T) = (TMP))
 501
 502 extern int thread_count (void);
 503
 504 /* Switch context to thread THR.  Also sets the STOP_PC global.  */
 505 extern void switch_to_thread (struct thread_info *thr);
 506
 507 /* Switch context to no thread selected.  */
 508 extern void switch_to_no_thread ();
 509
 510 /* Switch from one thread to another.  Does not read registers.  */
 511 extern void switch_to_thread_no_regs (struct thread_info *thread);
 512
 513 /* Marks or clears thread(s) PTID as resumed.  If PTID is
 514    MINUS_ONE_PTID, applies to all threads.  If ptid_is_pid(PTID) is
 515    true, applies to all threads of the process pointed at by PTID.  */
 516 extern void set_resumed (ptid_t ptid, int resumed);
 517
 518 /* Marks thread PTID is running, or stopped.
 519    If PTID is minus_one_ptid, marks all threads.  */
 520 extern void set_running (ptid_t ptid, int running);
 521
 522 /* Marks or clears thread(s) PTID as having been requested to stop.
 523    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 524    ptid_is_pid(PTID) is true, applies to all threads of the process
 525    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 526    observer is called with PTID as argument.  */
 527 extern void set_stop_requested (ptid_t ptid, int stop);
 528
 529 /* NOTE: Since the thread state is not a boolean, most times, you do
 530    not want to check it with negation.  If you really want to check if
 531    the thread is stopped,
 532
 533     use (good):
 534
 535      if (is_stopped (ptid))
 536
 537     instead of (bad):
 538
 539      if (!is_running (ptid))
 540
 541    The latter also returns true on exited threads, most likelly not
 542    what you want.  */
 543
 544 /* Reports if in the frontend's perpective, thread PTID is running.  */
 545 extern int is_running (ptid_t ptid);
 546
 547 /* Is this thread listed, but known to have exited?  We keep it listed
 548    (but not visible) until it's safe to delete.  */
 549 extern int is_exited (ptid_t ptid);
 550
 551 /* In the frontend's perpective, is this thread stopped?  */
 552 extern int is_stopped (ptid_t ptid);
 553
 554 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 555    marks all threads.
 556
 557    Note that this is different from the running state.  See the
 558    description of state and executing fields of struct
 559    thread_info.  */
 560 extern void set_executing (ptid_t ptid, int executing);
 561
 562 /* True if any (known or unknown) thread is or may be executing.  */
 563 extern int threads_are_executing (void);
 564
 565 /* Merge the executing property of thread PTID over to its thread
 566    state property (frontend running/stopped view).
 567
 568    "not executing" -> "stopped"
 569    "executing"     -> "running"
 570    "exited"        -> "exited"
 571
 572    If PTID is minus_one_ptid, go over all threads.
 573
 574    Notifications are only emitted if the thread state did change.  */
 575 extern void finish_thread_state (ptid_t ptid);
 576
 577 /* Calls finish_thread_state on scope exit, unless release() is called
 578    to disengage.  */
 579 class scoped_finish_thread_state
 580 {
 581 public:
 582   explicit scoped_finish_thread_state (ptid_t ptid)
 583     : m_ptid (ptid)
 584   {}
 585
 586   ~scoped_finish_thread_state ()
 587   {
 588     if (!m_released)
 589       finish_thread_state (m_ptid);
 590   }
 591
 592   /* Disengage.  */
 593   void release ()
 594   {
 595     m_released = true;
 596   }
 597
 598   DISABLE_COPY_AND_ASSIGN (scoped_finish_thread_state);
 599
 600 private:
 601   bool m_released = false;
 602   ptid_t m_ptid;
 603 };
 604
 605 /* Commands with a prefix of `thread'.  */
 606 extern struct cmd_list_element *thread_cmd_list;
 607
 608 extern void thread_command (const char *tidstr, int from_tty);
 609
 610 /* Print notices on thread events (attach, detach, etc.), set with
 611    `set print thread-events'.  */
 612 extern int print_thread_events;
 613
 614 /* Prints the list of threads and their details on UIOUT.  If
 615    REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
 616    print threads whose ID is included in the list.  If PID is not -1,
 617    only print threads from the process PID.  Otherwise, threads from
 618    all attached PIDs are printed.  If both REQUESTED_THREADS is not
 619    NULL and PID is not -1, then the thread is printed if it belongs to
 620    the specified process.  Otherwise, an error is raised.  */
 621 extern void print_thread_info (struct ui_out *uiout, char *requested_threads,
 622                                int pid);
 623
 624 /* Save/restore current inferior/thread/frame.  */
 625
 626 class scoped_restore_current_thread
 627 {
 628 public:
 629   scoped_restore_current_thread ();
 630   ~scoped_restore_current_thread ();
 631
 632   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
 633
 634 private:
 635   /* Use the "class" keyword here, because of a clash with a "thread_info"
 636      function in the Darwin API.  */
 637   class thread_info *m_thread;
 638   inferior *m_inf;
 639   frame_id m_selected_frame_id;
 640   int m_selected_frame_level;
 641   bool m_was_stopped;
 642 };
 643
 644 /* Returns a pointer into the thread_info corresponding to
 645    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 646 extern struct thread_info* inferior_thread (void);
 647
 648 extern void update_thread_list (void);
 649
 650 /* Delete any thread the target says is no longer alive.  */
 651
 652 extern void prune_threads (void);
 653
 654 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 655    does not consult the target about whether the thread is alive right
 656    now.  */
 657 extern void delete_exited_threads (void);
 658
 659 /* Return true if PC is in the stepping range of THREAD.  */
 660
 661 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 662
 663 /* Enable storing stack temporaries for thread THR and disable and
 664    clear the stack temporaries on destruction.  Holds a strong
 665    reference to THR.  */
 666
 667 class enable_thread_stack_temporaries
 668 {
 669 public:
 670
 671   explicit enable_thread_stack_temporaries (struct thread_info *thr)
 672     : m_thr (thr)
 673   {
 674     gdb_assert (m_thr != NULL);
 675
 676     m_thr->incref ();
 677
 678     m_thr->stack_temporaries_enabled = true;
 679     m_thr->stack_temporaries.clear ();
 680   }
 681
 682   ~enable_thread_stack_temporaries ()
 683   {
 684     m_thr->stack_temporaries_enabled = false;
 685     m_thr->stack_temporaries.clear ();
 686
 687     m_thr->decref ();
 688   }
 689
 690   DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
 691
 692 private:
 693
 694   struct thread_info *m_thr;
 695 };
 696
 697 extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
 698
 699 extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
 700
 701 extern value *get_last_thread_stack_temporary (struct thread_info *tp);
 702
 703 extern bool value_in_thread_stack_temporaries (struct value *,
 704                                                struct thread_info *thr);
 705
 706 /* Add TP to the end of its inferior's pending step-over chain.  */
 707
 708 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 709
 710 /* Remove TP from its inferior's pending step-over chain.  */
 711
 712 extern void thread_step_over_chain_remove (struct thread_info *tp);
 713
 714 /* Return the next thread in the step-over chain starting at TP.  NULL
 715    if TP is the last entry in the chain.  */
 716
 717 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 718
 719 /* Return true if TP is in the step-over chain.  */
 720
 721 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 722
 723 /* Cancel any ongoing execution command.  */
 724
 725 extern void thread_cancel_execution_command (struct thread_info *thr);
 726
 727 /* Check whether it makes sense to access a register of the current
 728    thread at this point.  If not, throw an error (e.g., the thread is
 729    executing).  */
 730 extern void validate_registers_access (void);
 731
 732 /* Check whether it makes sense to access a register of THREAD at this point.
 733    Returns true if registers may be accessed; false otherwise.  */
 734 extern bool can_access_registers_thread (struct thread_info *thread);
 735
 736 /* Returns whether to show which thread hit the breakpoint, received a
 737    signal, etc. and ended up causing a user-visible stop.  This is
 738    true iff we ever detected multiple threads.  */
 739 extern int show_thread_that_caused_stop (void);
 740
 741 /* Print the message for a thread or/and frame selected.  */
 742 extern void print_selected_thread_frame (struct ui_out *uiout,
 743                                          user_selected_what selection);
 744
 745 /* Helper for the CLI's "thread" command and for MI's -thread-select.
 746    Selects thread THR.  TIDSTR is the original string the thread ID
 747    was parsed from.  This is used in the error message if THR is not
 748    alive anymore.  */
 749 extern void thread_select (const char *tidstr, class thread_info *thr);
 750
 751 extern struct thread_info *thread_list;
 752
 753 #endif /* GDBTHREAD_H */