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