gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2016 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
  34 /* Frontend view of the thread state.  Possible extensions: stepping,
  35    finishing, until(ling),...  */
  36 enum thread_state
  37 {
  38   THREAD_STOPPED,
  39   THREAD_RUNNING,
  40   THREAD_EXITED,
  41 };
  42
  43 /* Inferior thread specific part of `struct infcall_control_state'.
  44
  45    Inferior process counterpart is `struct inferior_control_state'.  */
  46
  47 struct thread_control_state
  48 {
  49   /* User/external stepping state.  */
  50
  51   /* Step-resume or longjmp-resume breakpoint.  */
  52   struct breakpoint *step_resume_breakpoint;
  53
  54   /* Exception-resume breakpoint.  */
  55   struct breakpoint *exception_resume_breakpoint;
  56
  57   /* Breakpoints used for software single stepping.  Plural, because
  58      it may have multiple locations.  E.g., if stepping over a
  59      conditional branch instruction we can't decode the condition for,
  60      we'll need to put a breakpoint at the branch destination, and
  61      another at the instruction after the branch.  */
  62   struct breakpoint *single_step_breakpoints;
  63
  64   /* Range to single step within.
  65
  66      If this is nonzero, respond to a single-step signal by continuing
  67      to step if the pc is in this range.
  68
  69      If step_range_start and step_range_end are both 1, it means to
  70      step for a single instruction (FIXME: it might clean up
  71      wait_for_inferior in a minor way if this were changed to the
  72      address of the instruction and that address plus one.  But maybe
  73      not).  */
  74   CORE_ADDR step_range_start;   /* Inclusive */
  75   CORE_ADDR step_range_end;     /* Exclusive */
  76
  77   /* Function the thread was in as of last it started stepping.  */
  78   struct symbol *step_start_function;
  79
  80   /* If GDB issues a target step request, and this is nonzero, the
  81      target should single-step this thread once, and then continue
  82      single-stepping it without GDB core involvement as long as the
  83      thread stops in the step range above.  If this is zero, the
  84      target should ignore the step range, and only issue one single
  85      step.  */
  86   int may_range_step;
  87
  88   /* Stack frame address as of when stepping command was issued.
  89      This is how we know when we step into a subroutine call, and how
  90      to set the frame for the breakpoint used to step out.  */
  91   struct frame_id step_frame_id;
  92
  93   /* Similarly, the frame ID of the underlying stack frame (skipping
  94      any inlined frames).  */
  95   struct frame_id step_stack_frame_id;
  96
  97   /* Nonzero if we are presently stepping over a breakpoint.
  98
  99      If we hit a breakpoint or watchpoint, and then continue, we need
 100      to single step the current thread with breakpoints disabled, to
 101      avoid hitting the same breakpoint or watchpoint again.  And we
 102      should step just a single thread and keep other threads stopped,
 103      so that other threads don't miss breakpoints while they are
 104      removed.
 105
 106      So, this variable simultaneously means that we need to single
 107      step the current thread, keep other threads stopped, and that
 108      breakpoints should be removed while we step.
 109
 110      This variable is set either:
 111      - in proceed, when we resume inferior on user's explicit request
 112      - in keep_going, if handle_inferior_event decides we need to
 113      step over breakpoint.
 114
 115      The variable is cleared in normal_stop.  The proceed calls
 116      wait_for_inferior, which calls handle_inferior_event in a loop,
 117      and until wait_for_inferior exits, this variable is changed only
 118      by keep_going.  */
 119   int trap_expected;
 120
 121   /* Nonzero if the thread is being proceeded for a "finish" command
 122      or a similar situation when return value should be printed.  */
 123   int proceed_to_finish;
 124
 125   /* Nonzero if the thread is being proceeded for an inferior function
 126      call.  */
 127   int in_infcall;
 128
 129   enum step_over_calls_kind step_over_calls;
 130
 131   /* Nonzero if stopped due to a step command.  */
 132   int stop_step;
 133
 134   /* Chain containing status of breakpoint(s) the thread stopped
 135      at.  */
 136   bpstat stop_bpstat;
 137
 138   /* The interpreter that issued the execution command.  NULL if the
 139      thread was resumed as a result of a command applied to some other
 140      thread (e.g., "next" with scheduler-locking off).  */
 141   struct interp *command_interp;
 142
 143   /* Whether the command that started the thread was a stepping
 144      command.  This is used to decide whether "set scheduler-locking
 145      step" behaves like "on" or "off".  */
 146   int stepping_command;
 147 };
 148
 149 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 150
 151 struct thread_suspend_state
 152 {
 153   /* Last signal that the inferior received (why it stopped).  When
 154      the thread is resumed, this signal is delivered.  Note: the
 155      target should not check whether the signal is in pass state,
 156      because the signal may have been explicitly passed with the
 157      "signal" command, which overrides "handle nopass".  If the signal
 158      should be suppressed, the core will take care of clearing this
 159      before the target is resumed.  */
 160   enum gdb_signal stop_signal;
 161
 162   /* The reason the thread last stopped, if we need to track it
 163      (breakpoint, watchpoint, etc.)  */
 164   enum target_stop_reason stop_reason;
 165
 166   /* The waitstatus for this thread's last event.  */
 167   struct target_waitstatus waitstatus;
 168   /* If true WAITSTATUS hasn't been handled yet.  */
 169   int waitstatus_pending_p;
 170
 171   /* Record the pc of the thread the last time it stopped.  (This is
 172      not the current thread's PC as that may have changed since the
 173      last stop, e.g., "return" command, or "p $pc = 0xf000").  This is
 174      used in coordination with stop_reason and waitstatus_pending_p:
 175      if the thread's PC is changed since it last stopped, a pending
 176      breakpoint waitstatus is discarded.  */
 177   CORE_ADDR stop_pc;
 178 };
 179
 180 typedef struct value *value_ptr;
 181 DEF_VEC_P (value_ptr);
 182 typedef VEC (value_ptr) value_vec;
 183
 184 struct thread_info
 185 {
 186   struct thread_info *next;
 187   ptid_t ptid;                  /* "Actual process id";
 188                                     In fact, this may be overloaded with
 189                                     kernel thread id, etc.  */
 190   int num;                      /* Convenient handle (GDB thread id) */
 191
 192   /* The name of the thread, as specified by the user.  This is NULL
 193      if the thread does not have a user-given name.  */
 194   char *name;
 195
 196   /* Non-zero means the thread is executing.  Note: this is different
 197      from saying that there is an active target and we are stopped at
 198      a breakpoint, for instance.  This is a real indicator whether the
 199      thread is off and running.  */
 200   int executing;
 201
 202   /* Non-zero if this thread is resumed from infrun's perspective.
 203      Note that a thread can be marked both as not-executing and
 204      resumed at the same time.  This happens if we try to resume a
 205      thread that has a wait status pending.  We shouldn't let the
 206      thread really run until that wait status has been processed, but
 207      we should not process that wait status if we didn't try to let
 208      the thread run.  */
 209   int resumed;
 210
 211   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 212      THREAD_STOPPED states are different from EXECUTING.  When the
 213      thread is stopped internally while handling an internal event,
 214      like a software single-step breakpoint, EXECUTING will be false,
 215      but STATE will still be THREAD_RUNNING.  */
 216   enum thread_state state;
 217
 218   /* If this is > 0, then it means there's code out there that relies
 219      on this thread being listed.  Don't delete it from the lists even
 220      if we detect it exiting.  */
 221   int refcount;
 222
 223   /* State of GDB control of inferior thread execution.
 224      See `struct thread_control_state'.  */
 225   struct thread_control_state control;
 226
 227   /* State of inferior thread to restore after GDB is done with an inferior
 228      call.  See `struct thread_suspend_state'.  */
 229   struct thread_suspend_state suspend;
 230
 231   int current_line;
 232   struct symtab *current_symtab;
 233
 234   /* Internal stepping state.  */
 235
 236   /* Record the pc of the thread the last time it was resumed.  (It
 237      can't be done on stop as the PC may change since the last stop,
 238      e.g., "return" command, or "p $pc = 0xf000").  This is maintained
 239      by proceed and keep_going, and among other things, it's used in
 240      adjust_pc_after_break to distinguish a hardware single-step
 241      SIGTRAP from a breakpoint SIGTRAP.  */
 242   CORE_ADDR prev_pc;
 243
 244   /* Did we set the thread stepping a breakpoint instruction?  This is
 245      used in conjunction with PREV_PC to decide whether to adjust the
 246      PC.  */
 247   int stepped_breakpoint;
 248
 249   /* Should we step over breakpoint next time keep_going is called?  */
 250   int stepping_over_breakpoint;
 251
 252   /* Should we step over a watchpoint next time keep_going is called?
 253      This is needed on targets with non-continuable, non-steppable
 254      watchpoints.  */
 255   int stepping_over_watchpoint;
 256
 257   /* Set to TRUE if we should finish single-stepping over a breakpoint
 258      after hitting the current step-resume breakpoint.  The context here
 259      is that GDB is to do `next' or `step' while signal arrives.
 260      When stepping over a breakpoint and signal arrives, GDB will attempt
 261      to skip signal handler, so it inserts a step_resume_breakpoint at the
 262      signal return address, and resume inferior.
 263      step_after_step_resume_breakpoint is set to TRUE at this moment in
 264      order to keep GDB in mind that there is still a breakpoint to step over
 265      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 266   int step_after_step_resume_breakpoint;
 267
 268   /* Pointer to the state machine manager object that handles what is
 269      left to do for the thread's execution command after the target
 270      stops.  Several execution commands use it.  */
 271   struct thread_fsm *thread_fsm;
 272
 273   /* This is used to remember when a fork or vfork event was caught by
 274      a catchpoint, and thus the event is to be followed at the next
 275      resume of the thread, and not immediately.  */
 276   struct target_waitstatus pending_follow;
 277
 278   /* True if this thread has been explicitly requested to stop.  */
 279   int stop_requested;
 280
 281   /* The initiating frame of a nexting operation, used for deciding
 282      which exceptions to intercept.  If it is null_frame_id no
 283      bp_longjmp or bp_exception but longjmp has been caught just for
 284      bp_longjmp_call_dummy.  */
 285   struct frame_id initiating_frame;
 286
 287   /* Private data used by the target vector implementation.  */
 288   struct private_thread_info *priv;
 289
 290   /* Function that is called to free PRIVATE.  If this is NULL, then
 291      xfree will be called on PRIVATE.  */
 292   void (*private_dtor) (struct private_thread_info *);
 293
 294   /* Branch trace information for this thread.  */
 295   struct btrace_thread_info btrace;
 296
 297   /* Flag which indicates that the stack temporaries should be stored while
 298      evaluating expressions.  */
 299   int stack_temporaries_enabled;
 300
 301   /* Values that are stored as temporaries on stack while evaluating
 302      expressions.  */
 303   value_vec *stack_temporaries;
 304
 305   /* Step-over chain.  A thread is in the step-over queue if these are
 306      non-NULL.  If only a single thread is in the chain, then these
 307      fields point to self.  */
 308   struct thread_info *step_over_prev;
 309   struct thread_info *step_over_next;
 310 };
 311
 312 /* Create an empty thread list, or empty the existing one.  */
 313 extern void init_thread_list (void);
 314
 315 /* Add a thread to the thread list, print a message
 316    that a new thread is found, and return the pointer to
 317    the new thread.  Caller my use this pointer to
 318    initialize the private thread data.  */
 319 extern struct thread_info *add_thread (ptid_t ptid);
 320
 321 /* Same as add_thread, but does not print a message
 322    about new thread.  */
 323 extern struct thread_info *add_thread_silent (ptid_t ptid);
 324
 325 /* Same as add_thread, and sets the private info.  */
 326 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 327                                                  struct private_thread_info *);
 328
 329 /* Delete an existing thread list entry.  */
 330 extern void delete_thread (ptid_t);
 331
 332 /* Delete an existing thread list entry, and be quiet about it.  Used
 333    after the process this thread having belonged to having already
 334    exited, for example.  */
 335 extern void delete_thread_silent (ptid_t);
 336
 337 /* Delete a step_resume_breakpoint from the thread database.  */
 338 extern void delete_step_resume_breakpoint (struct thread_info *);
 339
 340 /* Delete an exception_resume_breakpoint from the thread database.  */
 341 extern void delete_exception_resume_breakpoint (struct thread_info *);
 342
 343 /* Delete the single-step breakpoints of thread TP, if any.  */
 344 extern void delete_single_step_breakpoints (struct thread_info *tp);
 345
 346 /* Check if the thread has software single stepping breakpoints
 347    set.  */
 348 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 349
 350 /* Check whether the thread has software single stepping breakpoints
 351    set at PC.  */
 352 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 353                                                    struct address_space *aspace,
 354                                                    CORE_ADDR addr);
 355
 356 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 357    into a "pid" (which may be overloaded with extra thread information).  */
 358 extern ptid_t thread_id_to_pid (int);
 359
 360 /* Translate a 'pid' (which may be overloaded with extra thread information)
 361    into the integer thread id (GDB's homegrown id, not the system's).  */
 362 extern int pid_to_thread_id (ptid_t ptid);
 363
 364 /* Return a string version of THR's thread ID.  The result is stored
 365    in a circular static buffer, NUMCELLS deep.  */
 366 const char *print_thread_id (struct thread_info *thr);
 367
 368 /* Boolean test for an already-known pid (which may be overloaded with
 369    extra thread information).  */
 370 extern int in_thread_list (ptid_t ptid);
 371
 372 /* Boolean test for an already-known thread id (GDB's homegrown id,
 373    not the system's).  */
 374 extern int valid_thread_id (int thread);
 375
 376 /* Search function to lookup a thread by 'pid'.  */
 377 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 378
 379 /* Find thread by GDB user-visible thread number.  */
 380 struct thread_info *find_thread_id (int num);
 381
 382 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 383    returns the first thread in the list.  */
 384 struct thread_info *first_thread_of_process (int pid);
 385
 386 /* Returns any thread of process PID, giving preference to the current
 387    thread.  */
 388 extern struct thread_info *any_thread_of_process (int pid);
 389
 390 /* Returns any non-exited thread of process PID, giving preference to
 391    the current thread, and to not executing threads.  */
 392 extern struct thread_info *any_live_thread_of_process (int pid);
 393
 394 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 395 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 396
 397 /* Iterator function to call a user-provided callback function
 398    once for each known thread.  */
 399 typedef int (*thread_callback_func) (struct thread_info *, void *);
 400 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 401
 402 /* Traverse all threads, except those that have THREAD_EXITED
 403    state.  */
 404
 405 #define ALL_NON_EXITED_THREADS(T)                               \
 406   for (T = thread_list; T; T = T->next) \
 407     if ((T)->state != THREAD_EXITED)
 408
 409 /* Traverse all threads, including those that have THREAD_EXITED
 410    state.  Allows deleting the currently iterated thread.  */
 411 #define ALL_THREADS_SAFE(T, TMP)        \
 412   for ((T) = thread_list;                       \
 413        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 414        (T) = (TMP))
 415
 416 extern int thread_count (void);
 417
 418 /* Switch from one thread to another.  Also sets the STOP_PC
 419    global.  */
 420 extern void switch_to_thread (ptid_t ptid);
 421
 422 /* Switch from one thread to another.  Does not read registers and
 423    sets STOP_PC to -1.  */
 424 extern void switch_to_thread_no_regs (struct thread_info *thread);
 425
 426 /* Marks or clears thread(s) PTID as resumed.  If PTID is
 427    MINUS_ONE_PTID, applies to all threads.  If ptid_is_pid(PTID) is
 428    true, applies to all threads of the process pointed at by PTID.  */
 429 extern void set_resumed (ptid_t ptid, int resumed);
 430
 431 /* Marks thread PTID is running, or stopped.
 432    If PTID is minus_one_ptid, marks all threads.  */
 433 extern void set_running (ptid_t ptid, int running);
 434
 435 /* Marks or clears thread(s) PTID as having been requested to stop.
 436    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 437    ptid_is_pid(PTID) is true, applies to all threads of the process
 438    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 439    observer is called with PTID as argument.  */
 440 extern void set_stop_requested (ptid_t ptid, int stop);
 441
 442 /* NOTE: Since the thread state is not a boolean, most times, you do
 443    not want to check it with negation.  If you really want to check if
 444    the thread is stopped,
 445
 446     use (good):
 447
 448      if (is_stopped (ptid))
 449
 450     instead of (bad):
 451
 452      if (!is_running (ptid))
 453
 454    The latter also returns true on exited threads, most likelly not
 455    what you want.  */
 456
 457 /* Reports if in the frontend's perpective, thread PTID is running.  */
 458 extern int is_running (ptid_t ptid);
 459
 460 /* Is this thread listed, but known to have exited?  We keep it listed
 461    (but not visible) until it's safe to delete.  */
 462 extern int is_exited (ptid_t ptid);
 463
 464 /* In the frontend's perpective, is this thread stopped?  */
 465 extern int is_stopped (ptid_t ptid);
 466
 467 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 468    marks all threads.
 469
 470    Note that this is different from the running state.  See the
 471    description of state and executing fields of struct
 472    thread_info.  */
 473 extern void set_executing (ptid_t ptid, int executing);
 474
 475 /* Reports if thread PTID is executing.  */
 476 extern int is_executing (ptid_t ptid);
 477
 478 /* True if any (known or unknown) thread is or may be executing.  */
 479 extern int threads_are_executing (void);
 480
 481 /* Merge the executing property of thread PTID over to its thread
 482    state property (frontend running/stopped view).
 483
 484    "not executing" -> "stopped"
 485    "executing"     -> "running"
 486    "exited"        -> "exited"
 487
 488    If PTID is minus_one_ptid, go over all threads.
 489
 490    Notifications are only emitted if the thread state did change.  */
 491 extern void finish_thread_state (ptid_t ptid);
 492
 493 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 494    registered as a cleanup.  PTID_P points to the ptid_t that is
 495    passed to FINISH_THREAD_STATE.  */
 496 extern void finish_thread_state_cleanup (void *ptid_p);
 497
 498 /* Commands with a prefix of `thread'.  */
 499 extern struct cmd_list_element *thread_cmd_list;
 500
 501 extern void thread_command (char *tidstr, int from_tty);
 502
 503 /* Print notices on thread events (attach, detach, etc.), set with
 504    `set print thread-events'.  */
 505 extern int print_thread_events;
 506
 507 extern void print_thread_info (struct ui_out *uiout, char *threads,
 508                                int pid);
 509
 510 extern struct cleanup *make_cleanup_restore_current_thread (void);
 511
 512 /* Returns a pointer into the thread_info corresponding to
 513    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 514 extern struct thread_info* inferior_thread (void);
 515
 516 extern void update_thread_list (void);
 517
 518 /* Delete any thread the target says is no longer alive.  */
 519
 520 extern void prune_threads (void);
 521
 522 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 523    does not consult the target about whether the thread is alive right
 524    now.  */
 525 extern void delete_exited_threads (void);
 526
 527 /* Return true if PC is in the stepping range of THREAD.  */
 528
 529 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 530
 531 extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid);
 532
 533 extern int thread_stack_temporaries_enabled_p (ptid_t ptid);
 534
 535 extern void push_thread_stack_temporary (ptid_t ptid, struct value *v);
 536
 537 extern struct value *get_last_thread_stack_temporary (ptid_t);
 538
 539 extern int value_in_thread_stack_temporaries (struct value *, ptid_t);
 540
 541 /* Add TP to the end of its inferior's pending step-over chain.  */
 542
 543 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 544
 545 /* Remove TP from its inferior's pending step-over chain.  */
 546
 547 extern void thread_step_over_chain_remove (struct thread_info *tp);
 548
 549 /* Return the next thread in the step-over chain starting at TP.  NULL
 550    if TP is the last entry in the chain.  */
 551
 552 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 553
 554 /* Return true if TP is in the step-over chain.  */
 555
 556 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 557
 558 /* Cancel any ongoing execution command.  */
 559
 560 extern void thread_cancel_execution_command (struct thread_info *thr);
 561
 562 /* Check whether it makes sense to access a register of the current
 563    thread at this point.  If not, throw an error (e.g., the thread is
 564    executing).  */
 565 extern void validate_registers_access (void);
 566
 567 extern struct thread_info *thread_list;
 568
 569 #endif /* GDBTHREAD_H */