gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2014 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
  32 /* Frontend view of the thread state.  Possible extensions: stepping,
  33    finishing, until(ling),...  */
  34 enum thread_state
  35 {
  36   THREAD_STOPPED,
  37   THREAD_RUNNING,
  38   THREAD_EXITED,
  39 };
  40
  41 /* Inferior thread specific part of `struct infcall_control_state'.
  42
  43    Inferior process counterpart is `struct inferior_control_state'.  */
  44
  45 struct thread_control_state
  46 {
  47   /* User/external stepping state.  */
  48
  49   /* Step-resume or longjmp-resume breakpoint.  */
  50   struct breakpoint *step_resume_breakpoint;
  51
  52   /* Exception-resume breakpoint.  */
  53   struct breakpoint *exception_resume_breakpoint;
  54
  55   /* Breakpoints used for software single stepping.  Plural, because
  56      it may have multiple locations.  E.g., if stepping over a
  57      conditional branch instruction we can't decode the condition for,
  58      we'll need to put a breakpoint at the branch destination, and
  59      another at the instruction after the branch.  */
  60   struct breakpoint *single_step_breakpoints;
  61
  62   /* Range to single step within.
  63
  64      If this is nonzero, respond to a single-step signal by continuing
  65      to step if the pc is in this range.
  66
  67      If step_range_start and step_range_end are both 1, it means to
  68      step for a single instruction (FIXME: it might clean up
  69      wait_for_inferior in a minor way if this were changed to the
  70      address of the instruction and that address plus one.  But maybe
  71      not).  */
  72   CORE_ADDR step_range_start;   /* Inclusive */
  73   CORE_ADDR step_range_end;     /* Exclusive */
  74
  75   /* If GDB issues a target step request, and this is nonzero, the
  76      target should single-step this thread once, and then continue
  77      single-stepping it without GDB core involvement as long as the
  78      thread stops in the step range above.  If this is zero, the
  79      target should ignore the step range, and only issue one single
  80      step.  */
  81   int may_range_step;
  82
  83   /* Stack frame address as of when stepping command was issued.
  84      This is how we know when we step into a subroutine call, and how
  85      to set the frame for the breakpoint used to step out.  */
  86   struct frame_id step_frame_id;
  87
  88   /* Similarly, the frame ID of the underlying stack frame (skipping
  89      any inlined frames).  */
  90   struct frame_id step_stack_frame_id;
  91
  92   /* Nonzero if we are presently stepping over a breakpoint.
  93
  94      If we hit a breakpoint or watchpoint, and then continue, we need
  95      to single step the current thread with breakpoints disabled, to
  96      avoid hitting the same breakpoint or watchpoint again.  And we
  97      should step just a single thread and keep other threads stopped,
  98      so that other threads don't miss breakpoints while they are
  99      removed.
 100
 101      So, this variable simultaneously means that we need to single
 102      step the current thread, keep other threads stopped, and that
 103      breakpoints should be removed while we step.
 104
 105      This variable is set either:
 106      - in proceed, when we resume inferior on user's explicit request
 107      - in keep_going, if handle_inferior_event decides we need to
 108      step over breakpoint.
 109
 110      The variable is cleared in normal_stop.  The proceed calls
 111      wait_for_inferior, which calls handle_inferior_event in a loop,
 112      and until wait_for_inferior exits, this variable is changed only
 113      by keep_going.  */
 114   int trap_expected;
 115
 116   /* Nonzero if the thread is being proceeded for a "finish" command
 117      or a similar situation when stop_registers should be saved.  */
 118   int proceed_to_finish;
 119
 120   /* Nonzero if the thread is being proceeded for an inferior function
 121      call.  */
 122   int in_infcall;
 123
 124   enum step_over_calls_kind step_over_calls;
 125
 126   /* Nonzero if stopped due to a step command.  */
 127   int stop_step;
 128
 129   /* Chain containing status of breakpoint(s) the thread stopped
 130      at.  */
 131   bpstat stop_bpstat;
 132
 133   /* The interpreter that issued the execution command.  NULL if the
 134      thread was resumed as a result of a command applied to some other
 135      thread (e.g., "next" with scheduler-locking off).  */
 136   struct interp *command_interp;
 137 };
 138
 139 /* Inferior thread specific part of `struct infcall_suspend_state'.
 140
 141    Inferior process counterpart is `struct inferior_suspend_state'.  */
 142
 143 struct thread_suspend_state
 144 {
 145   /* Last signal that the inferior received (why it stopped).  When
 146      the thread is resumed, this signal is delivered.  Note: the
 147      target should not check whether the signal is in pass state,
 148      because the signal may have been explicitly passed with the
 149      "signal" command, which overrides "handle nopass".  If the signal
 150      should be suppressed, the core will take care of clearing this
 151      before the target is resumed.  */
 152   enum gdb_signal stop_signal;
 153 };
 154
 155 struct thread_info
 156 {
 157   struct thread_info *next;
 158   ptid_t ptid;                  /* "Actual process id";
 159                                     In fact, this may be overloaded with
 160                                     kernel thread id, etc.  */
 161   int num;                      /* Convenient handle (GDB thread id) */
 162
 163   /* The name of the thread, as specified by the user.  This is NULL
 164      if the thread does not have a user-given name.  */
 165   char *name;
 166
 167   /* Non-zero means the thread is executing.  Note: this is different
 168      from saying that there is an active target and we are stopped at
 169      a breakpoint, for instance.  This is a real indicator whether the
 170      thread is off and running.  */
 171   int executing;
 172
 173   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 174      THREAD_STOPPED states are different from EXECUTING.  When the
 175      thread is stopped internally while handling an internal event,
 176      like a software single-step breakpoint, EXECUTING will be false,
 177      but STATE will still be THREAD_RUNNING.  */
 178   enum thread_state state;
 179
 180   /* If this is > 0, then it means there's code out there that relies
 181      on this thread being listed.  Don't delete it from the lists even
 182      if we detect it exiting.  */
 183   int refcount;
 184
 185   /* State of GDB control of inferior thread execution.
 186      See `struct thread_control_state'.  */
 187   struct thread_control_state control;
 188
 189   /* State of inferior thread to restore after GDB is done with an inferior
 190      call.  See `struct thread_suspend_state'.  */
 191   struct thread_suspend_state suspend;
 192
 193   int current_line;
 194   struct symtab *current_symtab;
 195
 196   /* Internal stepping state.  */
 197
 198   /* Record the pc of the thread the last time it stopped.  This is
 199      maintained by proceed and keep_going, and used in
 200      adjust_pc_after_break to distinguish a hardware single-step
 201      SIGTRAP from a breakpoint SIGTRAP.  */
 202   CORE_ADDR prev_pc;
 203
 204   /* Should we step over breakpoint next time keep_going is called?  */
 205   int stepping_over_breakpoint;
 206
 207   /* Should we step over a watchpoint next time keep_going is called?
 208      This is needed on targets with non-continuable, non-steppable
 209      watchpoints.  */
 210   int stepping_over_watchpoint;
 211
 212   /* Set to TRUE if we should finish single-stepping over a breakpoint
 213      after hitting the current step-resume breakpoint.  The context here
 214      is that GDB is to do `next' or `step' while signal arrives.
 215      When stepping over a breakpoint and signal arrives, GDB will attempt
 216      to skip signal handler, so it inserts a step_resume_breakpoint at the
 217      signal return address, and resume inferior.
 218      step_after_step_resume_breakpoint is set to TRUE at this moment in
 219      order to keep GDB in mind that there is still a breakpoint to step over
 220      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 221   int step_after_step_resume_breakpoint;
 222
 223   /* Per-thread command support.  */
 224
 225   /* Pointer to what is left to do for an execution command after the
 226      target stops.  Used only in asynchronous mode, by targets that
 227      support async execution.  Several execution commands use it.  */
 228   struct continuation *continuations;
 229
 230   /* Similar to the above, but used when a single execution command
 231      requires several resume/stop iterations.  Used by the step
 232      command.  */
 233   struct continuation *intermediate_continuations;
 234
 235   /* If stepping, nonzero means step count is > 1 so don't print frame
 236      next time inferior stops if it stops due to stepping.  */
 237   int step_multi;
 238
 239   /* This is used to remember when a fork or vfork event was caught by
 240      a catchpoint, and thus the event is to be followed at the next
 241      resume of the thread, and not immediately.  */
 242   struct target_waitstatus pending_follow;
 243
 244   /* True if this thread has been explicitly requested to stop.  */
 245   int stop_requested;
 246
 247   /* The initiating frame of a nexting operation, used for deciding
 248      which exceptions to intercept.  If it is null_frame_id no
 249      bp_longjmp or bp_exception but longjmp has been caught just for
 250      bp_longjmp_call_dummy.  */
 251   struct frame_id initiating_frame;
 252
 253   /* Private data used by the target vector implementation.  */
 254   struct private_thread_info *private;
 255
 256   /* Function that is called to free PRIVATE.  If this is NULL, then
 257      xfree will be called on PRIVATE.  */
 258   void (*private_dtor) (struct private_thread_info *);
 259
 260   /* Branch trace information for this thread.  */
 261   struct btrace_thread_info btrace;
 262 };
 263
 264 /* Create an empty thread list, or empty the existing one.  */
 265 extern void init_thread_list (void);
 266
 267 /* Add a thread to the thread list, print a message
 268    that a new thread is found, and return the pointer to
 269    the new thread.  Caller my use this pointer to
 270    initialize the private thread data.  */
 271 extern struct thread_info *add_thread (ptid_t ptid);
 272
 273 /* Same as add_thread, but does not print a message
 274    about new thread.  */
 275 extern struct thread_info *add_thread_silent (ptid_t ptid);
 276
 277 /* Same as add_thread, and sets the private info.  */
 278 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 279                                                  struct private_thread_info *);
 280
 281 /* Delete an existing thread list entry.  */
 282 extern void delete_thread (ptid_t);
 283
 284 /* Delete an existing thread list entry, and be quiet about it.  Used
 285    after the process this thread having belonged to having already
 286    exited, for example.  */
 287 extern void delete_thread_silent (ptid_t);
 288
 289 /* Delete a step_resume_breakpoint from the thread database.  */
 290 extern void delete_step_resume_breakpoint (struct thread_info *);
 291
 292 /* Delete an exception_resume_breakpoint from the thread database.  */
 293 extern void delete_exception_resume_breakpoint (struct thread_info *);
 294
 295 /* Delete the single-step breakpoints of thread TP, if any.  */
 296 extern void delete_single_step_breakpoints (struct thread_info *tp);
 297
 298 /* Check if the thread has software single stepping breakpoints
 299    set.  */
 300 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 301
 302 /* Check whether the thread has software single stepping breakpoints
 303    set at PC.  */
 304 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 305                                                    struct address_space *aspace,
 306                                                    CORE_ADDR addr);
 307
 308 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 309    into a "pid" (which may be overloaded with extra thread information).  */
 310 extern ptid_t thread_id_to_pid (int);
 311
 312 /* Translate a 'pid' (which may be overloaded with extra thread information)
 313    into the integer thread id (GDB's homegrown id, not the system's).  */
 314 extern int pid_to_thread_id (ptid_t ptid);
 315
 316 /* Boolean test for an already-known pid (which may be overloaded with
 317    extra thread information).  */
 318 extern int in_thread_list (ptid_t ptid);
 319
 320 /* Boolean test for an already-known thread id (GDB's homegrown id,
 321    not the system's).  */
 322 extern int valid_thread_id (int thread);
 323
 324 /* Search function to lookup a thread by 'pid'.  */
 325 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 326
 327 /* Find thread by GDB user-visible thread number.  */
 328 struct thread_info *find_thread_id (int num);
 329
 330 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 331    returns the first thread in the list.  */
 332 struct thread_info *first_thread_of_process (int pid);
 333
 334 /* Returns any thread of process PID, giving preference to the current
 335    thread.  */
 336 extern struct thread_info *any_thread_of_process (int pid);
 337
 338 /* Returns any non-exited thread of process PID, giving preference to
 339    the current thread, and to not executing threads.  */
 340 extern struct thread_info *any_live_thread_of_process (int pid);
 341
 342 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 343 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 344
 345 /* Iterator function to call a user-provided callback function
 346    once for each known thread.  */
 347 typedef int (*thread_callback_func) (struct thread_info *, void *);
 348 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 349
 350 /* Traverse all threads, except those that have THREAD_EXITED
 351    state.  */
 352
 353 #define ALL_NON_EXITED_THREADS(T)                               \
 354   for (T = thread_list; T; T = T->next) \
 355     if ((T)->state != THREAD_EXITED)
 356
 357 /* Like ALL_NON_EXITED_THREADS, but allows deleting the currently
 358    iterated thread.  */
 359 #define ALL_NON_EXITED_THREADS_SAFE(T, TMP)     \
 360   for ((T) = thread_list;                       \
 361        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 362        (T) = (TMP))                             \
 363     if ((T)->state != THREAD_EXITED)
 364
 365 extern int thread_count (void);
 366
 367 /* Switch from one thread to another.  */
 368 extern void switch_to_thread (ptid_t ptid);
 369
 370 /* Marks thread PTID is running, or stopped.
 371    If ptid_get_pid (PTID) is -1, marks all threads.  */
 372 extern void set_running (ptid_t ptid, int running);
 373
 374 /* Marks or clears thread(s) PTID as having been requested to stop.
 375    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 376    ptid_is_pid(PTID) is true, applies to all threads of the process
 377    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 378    observer is called with PTID as argument.  */
 379 extern void set_stop_requested (ptid_t ptid, int stop);
 380
 381 /* NOTE: Since the thread state is not a boolean, most times, you do
 382    not want to check it with negation.  If you really want to check if
 383    the thread is stopped,
 384
 385     use (good):
 386
 387      if (is_stopped (ptid))
 388
 389     instead of (bad):
 390
 391      if (!is_running (ptid))
 392
 393    The latter also returns true on exited threads, most likelly not
 394    what you want.  */
 395
 396 /* Reports if in the frontend's perpective, thread PTID is running.  */
 397 extern int is_running (ptid_t ptid);
 398
 399 /* Is this thread listed, but known to have exited?  We keep it listed
 400    (but not visible) until it's safe to delete.  */
 401 extern int is_exited (ptid_t ptid);
 402
 403 /* In the frontend's perpective, is this thread stopped?  */
 404 extern int is_stopped (ptid_t ptid);
 405
 406 /* Marks thread PTID as executing, or not.  If ptid_get_pid (PTID) is -1,
 407    marks all threads.
 408
 409    Note that this is different from the running state.  See the
 410    description of state and executing fields of struct
 411    thread_info.  */
 412 extern void set_executing (ptid_t ptid, int executing);
 413
 414 /* Reports if thread PTID is executing.  */
 415 extern int is_executing (ptid_t ptid);
 416
 417 /* True if any (known or unknown) thread is or may be executing.  */
 418 extern int threads_are_executing (void);
 419
 420 /* Merge the executing property of thread PTID over to its thread
 421    state property (frontend running/stopped view).
 422
 423    "not executing" -> "stopped"
 424    "executing"     -> "running"
 425    "exited"        -> "exited"
 426
 427    If ptid_get_pid (PTID) is -1, go over all threads.
 428
 429    Notifications are only emitted if the thread state did change.  */
 430 extern void finish_thread_state (ptid_t ptid);
 431
 432 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 433    registered as a cleanup.  PTID_P points to the ptid_t that is
 434    passed to FINISH_THREAD_STATE.  */
 435 extern void finish_thread_state_cleanup (void *ptid_p);
 436
 437 /* Commands with a prefix of `thread'.  */
 438 extern struct cmd_list_element *thread_cmd_list;
 439
 440 /* Print notices on thread events (attach, detach, etc.), set with
 441    `set print thread-events'.  */
 442 extern int print_thread_events;
 443
 444 extern void print_thread_info (struct ui_out *uiout, char *threads,
 445                                int pid);
 446
 447 extern struct cleanup *make_cleanup_restore_current_thread (void);
 448
 449 /* Returns a pointer into the thread_info corresponding to
 450    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 451 extern struct thread_info* inferior_thread (void);
 452
 453 extern void update_thread_list (void);
 454
 455 /* Delete any thread the target says is no longer alive.  */
 456
 457 extern void prune_threads (void);
 458
 459 /* Return true if PC is in the stepping range of THREAD.  */
 460
 461 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 462
 463 extern struct thread_info *thread_list;
 464
 465 #endif /* GDBTHREAD_H */