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   /* Set to TRUE if we should finish single-stepping over a breakpoint
 201      after hitting the current step-resume breakpoint.  The context here
 202      is that GDB is to do `next' or `step' while signal arrives.
 203      When stepping over a breakpoint and signal arrives, GDB will attempt
 204      to skip signal handler, so it inserts a step_resume_breakpoint at the
 205      signal return address, and resume inferior.
 206      step_after_step_resume_breakpoint is set to TRUE at this moment in
 207      order to keep GDB in mind that there is still a breakpoint to step over
 208      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 209   int step_after_step_resume_breakpoint;
 210
 211   /* Per-thread command support.  */
 212
 213   /* Pointer to what is left to do for an execution command after the
 214      target stops.  Used only in asynchronous mode, by targets that
 215      support async execution.  Several execution commands use it.  */
 216   struct continuation *continuations;
 217
 218   /* Similar to the above, but used when a single execution command
 219      requires several resume/stop iterations.  Used by the step
 220      command.  */
 221   struct continuation *intermediate_continuations;
 222
 223   /* If stepping, nonzero means step count is > 1 so don't print frame
 224      next time inferior stops if it stops due to stepping.  */
 225   int step_multi;
 226
 227   /* This is used to remember when a fork or vfork event was caught by
 228      a catchpoint, and thus the event is to be followed at the next
 229      resume of the thread, and not immediately.  */
 230   struct target_waitstatus pending_follow;
 231
 232   /* True if this thread has been explicitly requested to stop.  */
 233   int stop_requested;
 234
 235   /* The initiating frame of a nexting operation, used for deciding
 236      which exceptions to intercept.  If it is null_frame_id no
 237      bp_longjmp or bp_exception but longjmp has been caught just for
 238      bp_longjmp_call_dummy.  */
 239   struct frame_id initiating_frame;
 240
 241   /* Private data used by the target vector implementation.  */
 242   struct private_thread_info *private;
 243
 244   /* Function that is called to free PRIVATE.  If this is NULL, then
 245      xfree will be called on PRIVATE.  */
 246   void (*private_dtor) (struct private_thread_info *);
 247
 248   /* Branch trace information for this thread.  */
 249   struct btrace_thread_info btrace;
 250 };
 251
 252 /* Create an empty thread list, or empty the existing one.  */
 253 extern void init_thread_list (void);
 254
 255 /* Add a thread to the thread list, print a message
 256    that a new thread is found, and return the pointer to
 257    the new thread.  Caller my use this pointer to
 258    initialize the private thread data.  */
 259 extern struct thread_info *add_thread (ptid_t ptid);
 260
 261 /* Same as add_thread, but does not print a message
 262    about new thread.  */
 263 extern struct thread_info *add_thread_silent (ptid_t ptid);
 264
 265 /* Same as add_thread, and sets the private info.  */
 266 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 267                                                  struct private_thread_info *);
 268
 269 /* Delete an existing thread list entry.  */
 270 extern void delete_thread (ptid_t);
 271
 272 /* Delete an existing thread list entry, and be quiet about it.  Used
 273    after the process this thread having belonged to having already
 274    exited, for example.  */
 275 extern void delete_thread_silent (ptid_t);
 276
 277 /* Delete a step_resume_breakpoint from the thread database.  */
 278 extern void delete_step_resume_breakpoint (struct thread_info *);
 279
 280 /* Delete an exception_resume_breakpoint from the thread database.  */
 281 extern void delete_exception_resume_breakpoint (struct thread_info *);
 282
 283 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 284    into a "pid" (which may be overloaded with extra thread information).  */
 285 extern ptid_t thread_id_to_pid (int);
 286
 287 /* Translate a 'pid' (which may be overloaded with extra thread information)
 288    into the integer thread id (GDB's homegrown id, not the system's).  */
 289 extern int pid_to_thread_id (ptid_t ptid);
 290
 291 /* Boolean test for an already-known pid (which may be overloaded with
 292    extra thread information).  */
 293 extern int in_thread_list (ptid_t ptid);
 294
 295 /* Boolean test for an already-known thread id (GDB's homegrown id,
 296    not the system's).  */
 297 extern int valid_thread_id (int thread);
 298
 299 /* Search function to lookup a thread by 'pid'.  */
 300 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 301
 302 /* Find thread by GDB user-visible thread number.  */
 303 struct thread_info *find_thread_id (int num);
 304
 305 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 306    returns the first thread in the list.  */
 307 struct thread_info *first_thread_of_process (int pid);
 308
 309 /* Returns any thread of process PID.  */
 310 extern struct thread_info *any_thread_of_process (int pid);
 311
 312 /* Returns any non-exited thread of process PID, giving preference for
 313    not executing threads.  */
 314 extern struct thread_info *any_live_thread_of_process (int pid);
 315
 316 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 317 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 318
 319 /* Iterator function to call a user-provided callback function
 320    once for each known thread.  */
 321 typedef int (*thread_callback_func) (struct thread_info *, void *);
 322 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 323
 324 /* Traverse all threads, except those that have THREAD_EXITED
 325    state.  */
 326
 327 #define ALL_NON_EXITED_THREADS(T)                               \
 328   for (T = thread_list; T; T = T->next) \
 329     if ((T)->state != THREAD_EXITED)
 330
 331 extern int thread_count (void);
 332
 333 /* Switch from one thread to another.  */
 334 extern void switch_to_thread (ptid_t ptid);
 335
 336 /* Marks thread PTID is running, or stopped.
 337    If ptid_get_pid (PTID) is -1, marks all threads.  */
 338 extern void set_running (ptid_t ptid, int running);
 339
 340 /* Marks or clears thread(s) PTID as having been requested to stop.
 341    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 342    ptid_is_pid(PTID) is true, applies to all threads of the process
 343    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 344    observer is called with PTID as argument.  */
 345 extern void set_stop_requested (ptid_t ptid, int stop);
 346
 347 /* NOTE: Since the thread state is not a boolean, most times, you do
 348    not want to check it with negation.  If you really want to check if
 349    the thread is stopped,
 350
 351     use (good):
 352
 353      if (is_stopped (ptid))
 354
 355     instead of (bad):
 356
 357      if (!is_running (ptid))
 358
 359    The latter also returns true on exited threads, most likelly not
 360    what you want.  */
 361
 362 /* Reports if in the frontend's perpective, thread PTID is running.  */
 363 extern int is_running (ptid_t ptid);
 364
 365 /* Is this thread listed, but known to have exited?  We keep it listed
 366    (but not visible) until it's safe to delete.  */
 367 extern int is_exited (ptid_t ptid);
 368
 369 /* In the frontend's perpective, is this thread stopped?  */
 370 extern int is_stopped (ptid_t ptid);
 371
 372 /* Marks thread PTID as executing, or not.  If ptid_get_pid (PTID) is -1,
 373    marks all threads.
 374
 375    Note that this is different from the running state.  See the
 376    description of state and executing fields of struct
 377    thread_info.  */
 378 extern void set_executing (ptid_t ptid, int executing);
 379
 380 /* Reports if thread PTID is executing.  */
 381 extern int is_executing (ptid_t ptid);
 382
 383 /* Merge the executing property of thread PTID over to its thread
 384    state property (frontend running/stopped view).
 385
 386    "not executing" -> "stopped"
 387    "executing"     -> "running"
 388    "exited"        -> "exited"
 389
 390    If ptid_get_pid (PTID) is -1, go over all threads.
 391
 392    Notifications are only emitted if the thread state did change.  */
 393 extern void finish_thread_state (ptid_t ptid);
 394
 395 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 396    registered as a cleanup.  PTID_P points to the ptid_t that is
 397    passed to FINISH_THREAD_STATE.  */
 398 extern void finish_thread_state_cleanup (void *ptid_p);
 399
 400 /* Commands with a prefix of `thread'.  */
 401 extern struct cmd_list_element *thread_cmd_list;
 402
 403 /* Print notices on thread events (attach, detach, etc.), set with
 404    `set print thread-events'.  */
 405 extern int print_thread_events;
 406
 407 extern void print_thread_info (struct ui_out *uiout, char *threads,
 408                                int pid);
 409
 410 extern struct cleanup *make_cleanup_restore_current_thread (void);
 411
 412 /* Returns a pointer into the thread_info corresponding to
 413    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 414 extern struct thread_info* inferior_thread (void);
 415
 416 extern void update_thread_list (void);
 417
 418 /* Return true if PC is in the stepping range of THREAD.  */
 419
 420 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 421
 422 extern struct thread_info *thread_list;
 423
 424 #endif /* GDBTHREAD_H */