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