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