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 return value should be printed.  */
 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   /* Whether the command that started the thread was a stepping
 143      command.  This is used to decide whether "set scheduler-locking
 144      step" behaves like "on" or "off".  */
 145   int stepping_command;
 146 };
 147
 148 /* Inferior thread specific part of `struct infcall_suspend_state'.  */
 149
 150 struct thread_suspend_state
 151 {
 152   /* Last signal that the inferior received (why it stopped).  When
 153      the thread is resumed, this signal is delivered.  Note: the
 154      target should not check whether the signal is in pass state,
 155      because the signal may have been explicitly passed with the
 156      "signal" command, which overrides "handle nopass".  If the signal
 157      should be suppressed, the core will take care of clearing this
 158      before the target is resumed.  */
 159   enum gdb_signal stop_signal;
 160 };
 161
 162 typedef struct value *value_ptr;
 163 DEF_VEC_P (value_ptr);
 164 typedef VEC (value_ptr) value_vec;
 165
 166 struct thread_info
 167 {
 168   struct thread_info *next;
 169   ptid_t ptid;                  /* "Actual process id";
 170                                     In fact, this may be overloaded with
 171                                     kernel thread id, etc.  */
 172   int num;                      /* Convenient handle (GDB thread id) */
 173
 174   /* The name of the thread, as specified by the user.  This is NULL
 175      if the thread does not have a user-given name.  */
 176   char *name;
 177
 178   /* Non-zero means the thread is executing.  Note: this is different
 179      from saying that there is an active target and we are stopped at
 180      a breakpoint, for instance.  This is a real indicator whether the
 181      thread is off and running.  */
 182   int executing;
 183
 184   /* Frontend view of the thread state.  Note that the THREAD_RUNNING/
 185      THREAD_STOPPED states are different from EXECUTING.  When the
 186      thread is stopped internally while handling an internal event,
 187      like a software single-step breakpoint, EXECUTING will be false,
 188      but STATE will still be THREAD_RUNNING.  */
 189   enum thread_state state;
 190
 191   /* If this is > 0, then it means there's code out there that relies
 192      on this thread being listed.  Don't delete it from the lists even
 193      if we detect it exiting.  */
 194   int refcount;
 195
 196   /* State of GDB control of inferior thread execution.
 197      See `struct thread_control_state'.  */
 198   struct thread_control_state control;
 199
 200   /* State of inferior thread to restore after GDB is done with an inferior
 201      call.  See `struct thread_suspend_state'.  */
 202   struct thread_suspend_state suspend;
 203
 204   int current_line;
 205   struct symtab *current_symtab;
 206
 207   /* Internal stepping state.  */
 208
 209   /* Record the pc of the thread the last time it stopped.  This is
 210      maintained by proceed and keep_going, and used in
 211      adjust_pc_after_break to distinguish a hardware single-step
 212      SIGTRAP from a breakpoint SIGTRAP.  */
 213   CORE_ADDR prev_pc;
 214
 215   /* Did we set the thread stepping a breakpoint instruction?  This is
 216      used in conjunction with PREV_PC to decide whether to adjust the
 217      PC.  */
 218   int stepped_breakpoint;
 219
 220   /* Should we step over breakpoint next time keep_going is called?  */
 221   int stepping_over_breakpoint;
 222
 223   /* Should we step over a watchpoint next time keep_going is called?
 224      This is needed on targets with non-continuable, non-steppable
 225      watchpoints.  */
 226   int stepping_over_watchpoint;
 227
 228   /* Set to TRUE if we should finish single-stepping over a breakpoint
 229      after hitting the current step-resume breakpoint.  The context here
 230      is that GDB is to do `next' or `step' while signal arrives.
 231      When stepping over a breakpoint and signal arrives, GDB will attempt
 232      to skip signal handler, so it inserts a step_resume_breakpoint at the
 233      signal return address, and resume inferior.
 234      step_after_step_resume_breakpoint is set to TRUE at this moment in
 235      order to keep GDB in mind that there is still a breakpoint to step over
 236      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 237   int step_after_step_resume_breakpoint;
 238
 239   /* Per-thread command support.  */
 240
 241   /* Pointer to what is left to do for an execution command after the
 242      target stops.  Used only in asynchronous mode, by targets that
 243      support async execution.  Several execution commands use it.  */
 244   struct continuation *continuations;
 245
 246   /* Similar to the above, but used when a single execution command
 247      requires several resume/stop iterations.  Used by the step
 248      command.  */
 249   struct continuation *intermediate_continuations;
 250
 251   /* If stepping, nonzero means step count is > 1 so don't print frame
 252      next time inferior stops if it stops due to stepping.  */
 253   int step_multi;
 254
 255   /* This is used to remember when a fork or vfork event was caught by
 256      a catchpoint, and thus the event is to be followed at the next
 257      resume of the thread, and not immediately.  */
 258   struct target_waitstatus pending_follow;
 259
 260   /* True if this thread has been explicitly requested to stop.  */
 261   int stop_requested;
 262
 263   /* The initiating frame of a nexting operation, used for deciding
 264      which exceptions to intercept.  If it is null_frame_id no
 265      bp_longjmp or bp_exception but longjmp has been caught just for
 266      bp_longjmp_call_dummy.  */
 267   struct frame_id initiating_frame;
 268
 269   /* Private data used by the target vector implementation.  */
 270   struct private_thread_info *priv;
 271
 272   /* Function that is called to free PRIVATE.  If this is NULL, then
 273      xfree will be called on PRIVATE.  */
 274   void (*private_dtor) (struct private_thread_info *);
 275
 276   /* Branch trace information for this thread.  */
 277   struct btrace_thread_info btrace;
 278
 279   /* Flag which indicates that the stack temporaries should be stored while
 280      evaluating expressions.  */
 281   int stack_temporaries_enabled;
 282
 283   /* Values that are stored as temporaries on stack while evaluating
 284      expressions.  */
 285   value_vec *stack_temporaries;
 286
 287   /* Step-over chain.  A thread is in the step-over queue if these are
 288      non-NULL.  If only a single thread is in the chain, then these
 289      fields point to self.  */
 290   struct thread_info *step_over_prev;
 291   struct thread_info *step_over_next;
 292 };
 293
 294 /* Create an empty thread list, or empty the existing one.  */
 295 extern void init_thread_list (void);
 296
 297 /* Add a thread to the thread list, print a message
 298    that a new thread is found, and return the pointer to
 299    the new thread.  Caller my use this pointer to
 300    initialize the private thread data.  */
 301 extern struct thread_info *add_thread (ptid_t ptid);
 302
 303 /* Same as add_thread, but does not print a message
 304    about new thread.  */
 305 extern struct thread_info *add_thread_silent (ptid_t ptid);
 306
 307 /* Same as add_thread, and sets the private info.  */
 308 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 309                                                  struct private_thread_info *);
 310
 311 /* Delete an existing thread list entry.  */
 312 extern void delete_thread (ptid_t);
 313
 314 /* Delete an existing thread list entry, and be quiet about it.  Used
 315    after the process this thread having belonged to having already
 316    exited, for example.  */
 317 extern void delete_thread_silent (ptid_t);
 318
 319 /* Delete a step_resume_breakpoint from the thread database.  */
 320 extern void delete_step_resume_breakpoint (struct thread_info *);
 321
 322 /* Delete an exception_resume_breakpoint from the thread database.  */
 323 extern void delete_exception_resume_breakpoint (struct thread_info *);
 324
 325 /* Delete the single-step breakpoints of thread TP, if any.  */
 326 extern void delete_single_step_breakpoints (struct thread_info *tp);
 327
 328 /* Check if the thread has software single stepping breakpoints
 329    set.  */
 330 extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
 331
 332 /* Check whether the thread has software single stepping breakpoints
 333    set at PC.  */
 334 extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
 335                                                    struct address_space *aspace,
 336                                                    CORE_ADDR addr);
 337
 338 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 339    into a "pid" (which may be overloaded with extra thread information).  */
 340 extern ptid_t thread_id_to_pid (int);
 341
 342 /* Translate a 'pid' (which may be overloaded with extra thread information)
 343    into the integer thread id (GDB's homegrown id, not the system's).  */
 344 extern int pid_to_thread_id (ptid_t ptid);
 345
 346 /* Boolean test for an already-known pid (which may be overloaded with
 347    extra thread information).  */
 348 extern int in_thread_list (ptid_t ptid);
 349
 350 /* Boolean test for an already-known thread id (GDB's homegrown id,
 351    not the system's).  */
 352 extern int valid_thread_id (int thread);
 353
 354 /* Search function to lookup a thread by 'pid'.  */
 355 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 356
 357 /* Find thread by GDB user-visible thread number.  */
 358 struct thread_info *find_thread_id (int num);
 359
 360 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 361    returns the first thread in the list.  */
 362 struct thread_info *first_thread_of_process (int pid);
 363
 364 /* Returns any thread of process PID, giving preference to the current
 365    thread.  */
 366 extern struct thread_info *any_thread_of_process (int pid);
 367
 368 /* Returns any non-exited thread of process PID, giving preference to
 369    the current thread, and to not executing threads.  */
 370 extern struct thread_info *any_live_thread_of_process (int pid);
 371
 372 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 373 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 374
 375 /* Iterator function to call a user-provided callback function
 376    once for each known thread.  */
 377 typedef int (*thread_callback_func) (struct thread_info *, void *);
 378 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 379
 380 /* Traverse all threads, except those that have THREAD_EXITED
 381    state.  */
 382
 383 #define ALL_NON_EXITED_THREADS(T)                               \
 384   for (T = thread_list; T; T = T->next) \
 385     if ((T)->state != THREAD_EXITED)
 386
 387 /* Traverse all threads, including those that have THREAD_EXITED
 388    state.  Allows deleting the currently iterated thread.  */
 389 #define ALL_THREADS_SAFE(T, TMP)        \
 390   for ((T) = thread_list;                       \
 391        (T) != NULL ? ((TMP) = (T)->next, 1): 0; \
 392        (T) = (TMP))
 393
 394 extern int thread_count (void);
 395
 396 /* Switch from one thread to another.  */
 397 extern void switch_to_thread (ptid_t ptid);
 398
 399 /* Marks thread PTID is running, or stopped.
 400    If PTID is minus_one_ptid, marks all threads.  */
 401 extern void set_running (ptid_t ptid, int running);
 402
 403 /* Marks or clears thread(s) PTID as having been requested to stop.
 404    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 405    ptid_is_pid(PTID) is true, applies to all threads of the process
 406    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 407    observer is called with PTID as argument.  */
 408 extern void set_stop_requested (ptid_t ptid, int stop);
 409
 410 /* NOTE: Since the thread state is not a boolean, most times, you do
 411    not want to check it with negation.  If you really want to check if
 412    the thread is stopped,
 413
 414     use (good):
 415
 416      if (is_stopped (ptid))
 417
 418     instead of (bad):
 419
 420      if (!is_running (ptid))
 421
 422    The latter also returns true on exited threads, most likelly not
 423    what you want.  */
 424
 425 /* Reports if in the frontend's perpective, thread PTID is running.  */
 426 extern int is_running (ptid_t ptid);
 427
 428 /* Is this thread listed, but known to have exited?  We keep it listed
 429    (but not visible) until it's safe to delete.  */
 430 extern int is_exited (ptid_t ptid);
 431
 432 /* In the frontend's perpective, is this thread stopped?  */
 433 extern int is_stopped (ptid_t ptid);
 434
 435 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
 436    marks all threads.
 437
 438    Note that this is different from the running state.  See the
 439    description of state and executing fields of struct
 440    thread_info.  */
 441 extern void set_executing (ptid_t ptid, int executing);
 442
 443 /* Reports if thread PTID is executing.  */
 444 extern int is_executing (ptid_t ptid);
 445
 446 /* True if any (known or unknown) thread is or may be executing.  */
 447 extern int threads_are_executing (void);
 448
 449 /* Merge the executing property of thread PTID over to its thread
 450    state property (frontend running/stopped view).
 451
 452    "not executing" -> "stopped"
 453    "executing"     -> "running"
 454    "exited"        -> "exited"
 455
 456    If PTID is minus_one_ptid, go over all threads.
 457
 458    Notifications are only emitted if the thread state did change.  */
 459 extern void finish_thread_state (ptid_t ptid);
 460
 461 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 462    registered as a cleanup.  PTID_P points to the ptid_t that is
 463    passed to FINISH_THREAD_STATE.  */
 464 extern void finish_thread_state_cleanup (void *ptid_p);
 465
 466 /* Commands with a prefix of `thread'.  */
 467 extern struct cmd_list_element *thread_cmd_list;
 468
 469 extern void thread_command (char *tidstr, int from_tty);
 470
 471 /* Print notices on thread events (attach, detach, etc.), set with
 472    `set print thread-events'.  */
 473 extern int print_thread_events;
 474
 475 extern void print_thread_info (struct ui_out *uiout, char *threads,
 476                                int pid);
 477
 478 extern struct cleanup *make_cleanup_restore_current_thread (void);
 479
 480 /* Returns a pointer into the thread_info corresponding to
 481    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 482 extern struct thread_info* inferior_thread (void);
 483
 484 extern void update_thread_list (void);
 485
 486 /* Delete any thread the target says is no longer alive.  */
 487
 488 extern void prune_threads (void);
 489
 490 /* Delete threads marked THREAD_EXITED.  Unlike prune_threads, this
 491    does not consult the target about whether the thread is alive right
 492    now.  */
 493 extern void delete_exited_threads (void);
 494
 495 /* Return true if PC is in the stepping range of THREAD.  */
 496
 497 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 498
 499 extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid);
 500
 501 extern int thread_stack_temporaries_enabled_p (ptid_t ptid);
 502
 503 extern void push_thread_stack_temporary (ptid_t ptid, struct value *v);
 504
 505 extern struct value *get_last_thread_stack_temporary (ptid_t);
 506
 507 extern int value_in_thread_stack_temporaries (struct value *, ptid_t);
 508
 509 /* Add TP to the end of its inferior's pending step-over chain.  */
 510
 511 extern void thread_step_over_chain_enqueue (struct thread_info *tp);
 512
 513 /* Remove TP from its inferior's pending step-over chain.  */
 514
 515 extern void thread_step_over_chain_remove (struct thread_info *tp);
 516
 517 /* Return the next thread in the step-over chain starting at TP.  NULL
 518    if TP is the last entry in the chain.  */
 519
 520 extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
 521
 522 /* Return true if TP is in the step-over chain.  */
 523
 524 extern int thread_is_in_step_over_chain (struct thread_info *tp);
 525
 526 extern struct thread_info *thread_list;
 527
 528 #endif /* GDBTHREAD_H */