gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2015 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
  33 /* Frontend view of the thread state.  Possible extensions: stepping,
  34    finishing, until(ling),...  */
  35 enum thread_state
  36 {
  37   THREAD_STOPPED,
  38   THREAD_RUNNING,
  39   THREAD_EXITED,
  40 };
  41
  42 /* Inferior thread specific part of `struct infcall_control_state'.
  43
  44    Inferior process counterpart is `struct inferior_control_state'.  */
  45
  46 struct thread_control_state
  47 {
  48   /* User/external stepping state.  */
  49
  50   /* Step-resume or longjmp-resume breakpoint.  */
  51   struct breakpoint *step_resume_breakpoint;
  52
  53   /* Exception-resume breakpoint.  */
  54   struct breakpoint *exception_resume_breakpoint;
  55
  56   /* Breakpoints used for software single stepping.  Plural, because
  57      it may have multiple locations.  E.g., if stepping over a
  58      conditional branch instruction we can't decode the condition for,
  59      we'll need to put a breakpoint at the branch destination, and
  60      another at the instruction after the branch.  */
  61   struct breakpoint *single_step_breakpoints;
  62
  63   /* Range to single step within.
  64
  65      If this is nonzero, respond to a single-step signal by continuing
  66      to step if the pc is in this range.
  67
  68      If step_range_start and step_range_end are both 1, it means to
  69      step for a single instruction (FIXME: it might clean up
  70      wait_for_inferior in a minor way if this were changed to the
  71      address of the instruction and that address plus one.  But maybe
  72      not).  */
  73   CORE_ADDR step_range_start;   /* Inclusive */
  74   CORE_ADDR step_range_end;     /* Exclusive */
  75
  76   /* Function the thread was in as of last it started stepping.  */
  77   struct symbol *step_start_function;
  78
  79   /* If GDB issues a target step request, and this is nonzero, the
  80      target should single-step this thread once, and then continue
  81      single-stepping it without GDB core involvement as long as the
  82      thread stops in the step range above.  If this is zero, the
  83      target should ignore the step range, and only issue one single
  84      step.  */
  85   int may_range_step;
  86
  87   /* Stack frame address as of when stepping command was issued.
  88      This is how we know when we step into a subroutine call, and how
  89      to set the frame for the breakpoint used to step out.  */
  90   struct frame_id step_frame_id;
  91
  92   /* Similarly, the frame ID of the underlying stack frame (skipping
  93      any inlined frames).  */
  94   struct frame_id step_stack_frame_id;
  95
  96   /* Nonzero if we are presently stepping over a breakpoint.
  97
  98      If we hit a breakpoint or watchpoint, and then continue, we need
  99      to single step the current thread with breakpoints disabled, to
 100      avoid hitting the same breakpoint or watchpoint again.  And we
 101      should step just a single thread and keep other threads stopped,
 102      so that other threads don't miss breakpoints while they are
 103      removed.
 104
 105      So, this variable simultaneously means that we need to single
 106      step the current thread, keep other threads stopped, and that
 107      breakpoints should be removed while we step.
 108
 109      This variable is set either:
 110      - in proceed, when we resume inferior on user's explicit request
 111      - in keep_going, if handle_inferior_event decides we need to
 112      step over breakpoint.
 113
 114      The variable is cleared in normal_stop.  The proceed calls
 115      wait_for_inferior, which calls handle_inferior_event in a loop,
 116      and until wait_for_inferior exits, this variable is changed only
 117      by keep_going.  */
 118   int trap_expected;
 119
 120   /* Nonzero if the thread is being proceeded for a "finish" command
 121      or a similar situation when stop_registers should be saved.  */
 122   int proceed_to_finish;
 123
 124   /* Nonzero if the thread is being proceeded for an inferior function
 125      call.  */
 126   int in_infcall;
 127
 128   enum step_over_calls_kind step_over_calls;
 129
 130   /* Nonzero if stopped due to a step command.  */
 131   int stop_step;
 132
 133   /* Chain containing status of breakpoint(s) the thread stopped
 134      at.  */
 135   bpstat stop_bpstat;
 136
 137   /* The interpreter that issued the execution command.  NULL if the
 138      thread was resumed as a result of a command applied to some other
 139      thread (e.g., "next" with scheduler-locking off).  */
 140   struct interp *command_interp;
 141 };
 142
 143 /* Inferior thread specific part of `struct infcall_suspend_state'.
 144
 145    Inferior process counterpart is `struct inferior_suspend_state'.  */
 146
 147 struct thread_suspend_state
 148 {
 149   /* Last signal that the inferior received (why it stopped).  When
 150      the thread is resumed, this signal is delivered.  Note: the
 151      target should not check whether the signal is in pass state,
 152      because the signal may have been explicitly passed with the
 153      "signal" command, which overrides "handle nopass".  If the signal
 154      should be suppressed, the core will take care of clearing this
 155      before the target is resumed.  */
 156   enum gdb_signal stop_signal;
 157 };
 158
 159 typedef struct value *value_ptr;
 160 DEF_VEC_P (value_ptr);
 161 typedef VEC (value_ptr) value_vec;
 162
 163 struct thread_info
 164 {
 165   struct thread_info *next;
 166   ptid_t ptid;                  /* "Actual process id";
 167                                     In fact, this may be overloaded with
 168                                     kernel thread id, etc.  */
 169   int num;                      /* Convenient handle (GDB thread id) */
 170
 171   /* The name of the thread, as specified by the user.  This is NULL
 172      if the thread does not have a user-given name.  */
 173   char *name;
 174
 175   /* Non-zero means the thread is executing.  Note: this is different
 176      from saying that there is an active target and we are stopped at
 177      a breakpoint, for instance.  This is a real indicator whether the
 178      thread is off and running.  */
 179   int executing;
 180
 181   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 182      THREAD_STOPPED states are different from EXECUTING.  When the
 183      thread is stopped internally while handling an internal event,
 184      like a software single-step breakpoint, EXECUTING will be false,
 185      but STATE will still be THREAD_RUNNING.  */
 186   enum thread_state state;
 187
 188   /* If this is > 0, then it means there's code out there that relies
 189      on this thread being listed.  Don't delete it from the lists even
 190      if we detect it exiting.  */
 191   int refcount;
 192
 193   /* State of GDB control of inferior thread execution.
 194      See `struct thread_control_state'.  */
 195   struct thread_control_state control;
 196
 197   /* State of inferior thread to restore after GDB is done with an inferior
 198      call.  See `struct thread_suspend_state'.  */
 199   struct thread_suspend_state suspend;
 200
 201   int current_line;
 202   struct symtab *current_symtab;
 203
 204   /* Internal stepping state.  */
 205
 206   /* Record the pc of the thread the last time it stopped.  This is
 207      maintained by proceed and keep_going, and used in
 208      adjust_pc_after_break to distinguish a hardware single-step
 209      SIGTRAP from a breakpoint SIGTRAP.  */
 210   CORE_ADDR prev_pc;
 211
 212   /* Did we set the thread stepping a breakpoint instruction?  This is
 213      used in conjunction with PREV_PC to decide whether to adjust the
 214      PC.  */
 215   int stepped_breakpoint;
 216
 217   /* Should we step over breakpoint next time keep_going is called?  */
 218   int stepping_over_breakpoint;
 219
 220   /* Should we step over a watchpoint next time keep_going is called?
 221      This is needed on targets with non-continuable, non-steppable
 222      watchpoints.  */
 223   int stepping_over_watchpoint;
 224
 225   /* Set to TRUE if we should finish single-stepping over a breakpoint
 226      after hitting the current step-resume breakpoint.  The context here
 227      is that GDB is to do `next' or `step' while signal arrives.
 228      When stepping over a breakpoint and signal arrives, GDB will attempt
 229      to skip signal handler, so it inserts a step_resume_breakpoint at the
 230      signal return address, and resume inferior.
 231      step_after_step_resume_breakpoint is set to TRUE at this moment in
 232      order to keep GDB in mind that there is still a breakpoint to step over
 233      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 234   int step_after_step_resume_breakpoint;
 235
 236   /* Per-thread command support.  */
 237
 238   /* Pointer to what is left to do for an execution command after the
 239      target stops.  Used only in asynchronous mode, by targets that
 240      support async execution.  Several execution commands use it.  */
 241   struct continuation *continuations;
 242
 243   /* Similar to the above, but used when a single execution command
 244      requires several resume/stop iterations.  Used by the step
 245      command.  */
 246   struct continuation *intermediate_continuations;
 247
 248   /* If stepping, nonzero means step count is > 1 so don't print frame
 249      next time inferior stops if it stops due to stepping.  */
 250   int step_multi;
 251
 252   /* This is used to remember when a fork or vfork event was caught by
 253      a catchpoint, and thus the event is to be followed at the next
 254      resume of the thread, and not immediately.  */
 255   struct target_waitstatus pending_follow;
 256
 257   /* True if this thread has been explicitly requested to stop.  */
 258   int stop_requested;
 259
 260   /* The initiating frame of a nexting operation, used for deciding
 261      which exceptions to intercept.  If it is null_frame_id no
 262      bp_longjmp or bp_exception but longjmp has been caught just for
 263      bp_longjmp_call_dummy.  */
 264   struct frame_id initiating_frame;
 265
 266   /* Private data used by the target vector implementation.  */
 267   struct private_thread_info *priv;
 268
 269   /* Function that is called to free PRIVATE.  If this is NULL, then
 270      xfree will be called on PRIVATE.  */
 271   void (*private_dtor) (struct private_thread_info *);
 272
 273   /* Branch trace information for this thread.  */
 274   struct btrace_thread_info btrace;
 275
 276   /* Flag which indicates that the stack temporaries should be stored while
 277      evaluating expressions.  */
 278   int stack_temporaries_enabled;
 279
 280   /* Values that are stored as temporaries on stack while evaluating
 281      expressions.  */
 282   value_vec *stack_temporaries;
 283 };
 284
 285 /* Create an empty thread list, or empty the existing one.  */
 286 extern void init_thread_list (void);
 287
 288 /* Add a thread to the thread list, print a message
 289    that a new thread is found, and return the pointer to
 290    the new thread.  Caller my use this pointer to
 291    initialize the private thread data.  */
 292 extern struct thread_info *add_thread (ptid_t ptid);
 293
 294 /* Same as add_thread, but does not print a message
 295    about new thread.  */
 296 extern struct thread_info *add_thread_silent (ptid_t ptid);
 297
 298 /* Same as add_thread, and sets the private info.  */
 299 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 300                                                  struct private_thread_info *);
 301
 302 /* Delete an existing thread list entry.  */
 303 extern void delete_thread (ptid_t);
 304
 305 /* Delete an existing thread list entry, and be quiet about it.  Used
 306    after the process this thread having belonged to having already
 307    exited, for example.  */
 308 extern void delete_thread_silent (ptid_t);
 309
 310 /* Delete a step_resume_breakpoint from the thread database.  */
 311 extern void delete_step_resume_breakpoint (struct thread_info *);
 312
 313 /* Delete an exception_resume_breakpoint from the thread database.  */
 314 extern void delete_exception_resume_breakpoint (struct thread_info *);
 315
 316 /* Delete the single-step breakpoints of thread TP, if any.  */
 317 extern void delete_single_step_breakpoints (struct thread_info *tp);
 318
 319 /* Check if the thread has software single stepping breakpoints
 320    set.  */
 321 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 322
 323 /* Check whether the thread has software single stepping breakpoints
 324    set at PC.  */
 325 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 326                                                    struct address_space *aspace,
 327                                                    CORE_ADDR addr);
 328
 329 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 330    into a "pid" (which may be overloaded with extra thread information).  */
 331 extern ptid_t thread_id_to_pid (int);
 332
 333 /* Translate a 'pid' (which may be overloaded with extra thread information)
 334    into the integer thread id (GDB's homegrown id, not the system's).  */
 335 extern int pid_to_thread_id (ptid_t ptid);
 336
 337 /* Boolean test for an already-known pid (which may be overloaded with
 338    extra thread information).  */
 339 extern int in_thread_list (ptid_t ptid);
 340
 341 /* Boolean test for an already-known thread id (GDB's homegrown id,
 342    not the system's).  */
 343 extern int valid_thread_id (int thread);
 344
 345 /* Search function to lookup a thread by 'pid'.  */
 346 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 347
 348 /* Find thread by GDB user-visible thread number.  */
 349 struct thread_info *find_thread_id (int num);
 350
 351 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 352    returns the first thread in the list.  */
 353 struct thread_info *first_thread_of_process (int pid);
 354
 355 /* Returns any thread of process PID, giving preference to the current
 356    thread.  */
 357 extern struct thread_info *any_thread_of_process (int pid);
 358
 359 /* Returns any non-exited thread of process PID, giving preference to
 360    the current thread, and to not executing threads.  */
 361 extern struct thread_info *any_live_thread_of_process (int pid);
 362
 363 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 364 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 365
 366 /* Iterator function to call a user-provided callback function
 367    once for each known thread.  */
 368 typedef int (*thread_callback_func) (struct thread_info *, void *);
 369 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 370
 371 /* Traverse all threads, except those that have THREAD_EXITED
 372    state.  */
 373
 374 #define ALL_NON_EXITED_THREADS(T)                               \
 375   for (T = thread_list; T; T = T->next) \
 376     if ((T)->state != THREAD_EXITED)
 377
 378 /* Like ALL_NON_EXITED_THREADS, but allows deleting the currently
 379    iterated thread.  */
 380 #define ALL_NON_EXITED_THREADS_SAFE(T, TMP)     \
 381   for ((T) = thread_list;                       \
 382        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 383        (T) = (TMP))                             \
 384     if ((T)->state != THREAD_EXITED)
 385
 386 extern int thread_count (void);
 387
 388 /* Switch from one thread to another.  */
 389 extern void switch_to_thread (ptid_t ptid);
 390
 391 /* Marks thread PTID is running, or stopped.
 392    If PTID is minus_one_ptid, marks all threads.  */
 393 extern void set_running (ptid_t ptid, int running);
 394
 395 /* Marks or clears thread(s) PTID as having been requested to stop.
 396    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 397    ptid_is_pid(PTID) is true, applies to all threads of the process
 398    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 399    observer is called with PTID as argument.  */
 400 extern void set_stop_requested (ptid_t ptid, int stop);
 401
 402 /* NOTE: Since the thread state is not a boolean, most times, you do
 403    not want to check it with negation.  If you really want to check if
 404    the thread is stopped,
 405
 406     use (good):
 407
 408      if (is_stopped (ptid))
 409
 410     instead of (bad):
 411
 412      if (!is_running (ptid))
 413
 414    The latter also returns true on exited threads, most likelly not
 415    what you want.  */
 416
 417 /* Reports if in the frontend's perpective, thread PTID is running.  */
 418 extern int is_running (ptid_t ptid);
 419
 420 /* Is this thread listed, but known to have exited?  We keep it listed
 421    (but not visible) until it's safe to delete.  */
 422 extern int is_exited (ptid_t ptid);
 423
 424 /* In the frontend's perpective, is this thread stopped?  */
 425 extern int is_stopped (ptid_t ptid);
 426
 427 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 428    marks all threads.
 429
 430    Note that this is different from the running state.  See the
 431    description of state and executing fields of struct
 432    thread_info.  */
 433 extern void set_executing (ptid_t ptid, int executing);
 434
 435 /* Reports if thread PTID is executing.  */
 436 extern int is_executing (ptid_t ptid);
 437
 438 /* True if any (known or unknown) thread is or may be executing.  */
 439 extern int threads_are_executing (void);
 440
 441 /* Merge the executing property of thread PTID over to its thread
 442    state property (frontend running/stopped view).
 443
 444    "not executing" -> "stopped"
 445    "executing"     -> "running"
 446    "exited"        -> "exited"
 447
 448    If PTID is minus_one_ptid, go over all threads.
 449
 450    Notifications are only emitted if the thread state did change.  */
 451 extern void finish_thread_state (ptid_t ptid);
 452
 453 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 454    registered as a cleanup.  PTID_P points to the ptid_t that is
 455    passed to FINISH_THREAD_STATE.  */
 456 extern void finish_thread_state_cleanup (void *ptid_p);
 457
 458 /* Commands with a prefix of `thread'.  */
 459 extern struct cmd_list_element *thread_cmd_list;
 460
 461 extern void thread_command (char *tidstr, int from_tty);
 462
 463 /* Print notices on thread events (attach, detach, etc.), set with
 464    `set print thread-events'.  */
 465 extern int print_thread_events;
 466
 467 extern void print_thread_info (struct ui_out *uiout, char *threads,
 468                                int pid);
 469
 470 extern struct cleanup *make_cleanup_restore_current_thread (void);
 471
 472 /* Returns a pointer into the thread_info corresponding to
 473    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 474 extern struct thread_info* inferior_thread (void);
 475
 476 extern void update_thread_list (void);
 477
 478 /* Delete any thread the target says is no longer alive.  */
 479
 480 extern void prune_threads (void);
 481
 482 /* Return true if PC is in the stepping range of THREAD.  */
 483
 484 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 485
 486 extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid);
 487
 488 extern int thread_stack_temporaries_enabled_p (ptid_t ptid);
 489
 490 extern void push_thread_stack_temporary (ptid_t ptid, struct value *v);
 491
 492 extern struct value *get_last_thread_stack_temporary (ptid_t);
 493
 494 extern int value_in_thread_stack_temporaries (struct value *, ptid_t);
 495
 496 extern struct thread_info *thread_list;
 497
 498 #endif /* GDBTHREAD_H */