gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-1993, 1997-2000, 2007-2012 Free Software
   3    Foundation, Inc.
   4    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   5
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef GDBTHREAD_H
  23 #define GDBTHREAD_H
  24
  25 struct symtab;
  26
  27 #include "breakpoint.h"
  28 #include "frame.h"
  29 #include "ui-out.h"
  30 #include "inferior.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   /* Stack frame address as of when stepping command was issued.
  69      This is how we know when we step into a subroutine call, and how
  70      to set the frame for the breakpoint used to step out.  */
  71   struct frame_id step_frame_id;
  72
  73   /* Similarly, the frame ID of the underlying stack frame (skipping
  74      any inlined frames).  */
  75   struct frame_id step_stack_frame_id;
  76
  77   /* Nonzero if we are presently stepping over a breakpoint.
  78
  79      If we hit a breakpoint or watchpoint, and then continue, we need
  80      to single step the current thread with breakpoints disabled, to
  81      avoid hitting the same breakpoint or watchpoint again.  And we
  82      should step just a single thread and keep other threads stopped,
  83      so that other threads don't miss breakpoints while they are
  84      removed.
  85
  86      So, this variable simultaneously means that we need to single
  87      step the current thread, keep other threads stopped, and that
  88      breakpoints should be removed while we step.
  89
  90      This variable is set either:
  91      - in proceed, when we resume inferior on user's explicit request
  92      - in keep_going, if handle_inferior_event decides we need to
  93      step over breakpoint.
  94
  95      The variable is cleared in normal_stop.  The proceed calls
  96      wait_for_inferior, which calls handle_inferior_event in a loop,
  97      and until wait_for_inferior exits, this variable is changed only
  98      by keep_going.  */
  99   int trap_expected;
 100
 101   /* Nonzero if the thread is being proceeded for a "finish" command
 102      or a similar situation when stop_registers should be saved.  */
 103   int proceed_to_finish;
 104
 105   /* Nonzero if the thread is being proceeded for an inferior function
 106      call.  */
 107   int in_infcall;
 108
 109   enum step_over_calls_kind step_over_calls;
 110
 111   /* Nonzero if stopped due to a step command.  */
 112   int stop_step;
 113
 114   /* Chain containing status of breakpoint(s) the thread stopped
 115      at.  */
 116   bpstat stop_bpstat;
 117 };
 118
 119 /* Inferior thread specific part of `struct infcall_suspend_state'.
 120
 121    Inferior process counterpart is `struct inferior_suspend_state'.  */
 122
 123 struct thread_suspend_state
 124 {
 125   /* Last signal that the inferior received (why it stopped).  */
 126   enum gdb_signal stop_signal;
 127 };
 128
 129 struct thread_info
 130 {
 131   struct thread_info *next;
 132   ptid_t ptid;                  /* "Actual process id";
 133                                     In fact, this may be overloaded with
 134                                     kernel thread id, etc.  */
 135   int num;                      /* Convenient handle (GDB thread id) */
 136
 137   /* The name of the thread, as specified by the user.  This is NULL
 138      if the thread does not have a user-given name.  */
 139   char *name;
 140
 141   /* Non-zero means the thread is executing.  Note: this is different
 142      from saying that there is an active target and we are stopped at
 143      a breakpoint, for instance.  This is a real indicator whether the
 144      thread is off and running.  */
 145   int executing;
 146
 147   /* Frontend view of the thread state.  Note that the RUNNING/STOPPED
 148      states are different from EXECUTING.  When the thread is stopped
 149      internally while handling an internal event, like a software
 150      single-step breakpoint, EXECUTING will be false, but running will
 151      still be true.  As a possible future extension, this could turn
 152      into enum { stopped, exited, stepping, finishing, until(ling),
 153      running ... }  */
 154   int state;
 155
 156   /* If this is > 0, then it means there's code out there that relies
 157      on this thread being listed.  Don't delete it from the lists even
 158      if we detect it exiting.  */
 159   int refcount;
 160
 161   /* State of GDB control of inferior thread execution.
 162      See `struct thread_control_state'.  */
 163   struct thread_control_state control;
 164
 165   /* State of inferior thread to restore after GDB is done with an inferior
 166      call.  See `struct thread_suspend_state'.  */
 167   struct thread_suspend_state suspend;
 168
 169   int current_line;
 170   struct symtab *current_symtab;
 171
 172   /* Internal stepping state.  */
 173
 174   /* Record the pc of the thread the last time it stopped.  This is
 175      maintained by proceed and keep_going, and used in
 176      adjust_pc_after_break to distinguish a hardware single-step
 177      SIGTRAP from a breakpoint SIGTRAP.  */
 178   CORE_ADDR prev_pc;
 179
 180   /* Should we step over breakpoint next time keep_going is called?  */
 181   int stepping_over_breakpoint;
 182
 183   /* Set to TRUE if we should finish single-stepping over a breakpoint
 184      after hitting the current step-resume breakpoint.  The context here
 185      is that GDB is to do `next' or `step' while signal arrives.
 186      When stepping over a breakpoint and signal arrives, GDB will attempt
 187      to skip signal handler, so it inserts a step_resume_breakpoint at the
 188      signal return address, and resume inferior.
 189      step_after_step_resume_breakpoint is set to TRUE at this moment in
 190      order to keep GDB in mind that there is still a breakpoint to step over
 191      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 192   int step_after_step_resume_breakpoint;
 193
 194   /* Per-thread command support.  */
 195
 196   /* Pointer to what is left to do for an execution command after the
 197      target stops.  Used only in asynchronous mode, by targets that
 198      support async execution.  Several execution commands use it.  */
 199   struct continuation *continuations;
 200
 201   /* Similar to the above, but used when a single execution command
 202      requires several resume/stop iterations.  Used by the step
 203      command.  */
 204   struct continuation *intermediate_continuations;
 205
 206   /* If stepping, nonzero means step count is > 1 so don't print frame
 207      next time inferior stops if it stops due to stepping.  */
 208   int step_multi;
 209
 210   /* This is used to remember when a fork or vfork event was caught by
 211      a catchpoint, and thus the event is to be followed at the next
 212      resume of the thread, and not immediately.  */
 213   struct target_waitstatus pending_follow;
 214
 215   /* True if this thread has been explicitly requested to stop.  */
 216   int stop_requested;
 217
 218   /* The initiating frame of a nexting operation, used for deciding
 219      which exceptions to intercept.  If it is null_frame_id no
 220      bp_longjmp or bp_exception but longjmp has been caught just for
 221      bp_longjmp_call_dummy.  */
 222   struct frame_id initiating_frame;
 223
 224   /* Private data used by the target vector implementation.  */
 225   struct private_thread_info *private;
 226
 227   /* Function that is called to free PRIVATE.  If this is NULL, then
 228      xfree will be called on PRIVATE.  */
 229   void (*private_dtor) (struct private_thread_info *);
 230 };
 231
 232 /* Create an empty thread list, or empty the existing one.  */
 233 extern void init_thread_list (void);
 234
 235 /* Add a thread to the thread list, print a message
 236    that a new thread is found, and return the pointer to
 237    the new thread.  Caller my use this pointer to
 238    initialize the private thread data.  */
 239 extern struct thread_info *add_thread (ptid_t ptid);
 240
 241 /* Same as add_thread, but does not print a message
 242    about new thread.  */
 243 extern struct thread_info *add_thread_silent (ptid_t ptid);
 244
 245 /* Same as add_thread, and sets the private info.  */
 246 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 247                                                  struct private_thread_info *);
 248
 249 /* Delete an existing thread list entry.  */
 250 extern void delete_thread (ptid_t);
 251
 252 /* Delete an existing thread list entry, and be quiet about it.  Used
 253    after the process this thread having belonged to having already
 254    exited, for example.  */
 255 extern void delete_thread_silent (ptid_t);
 256
 257 /* Delete a step_resume_breakpoint from the thread database.  */
 258 extern void delete_step_resume_breakpoint (struct thread_info *);
 259
 260 /* Delete an exception_resume_breakpoint from the thread database.  */
 261 extern void delete_exception_resume_breakpoint (struct thread_info *);
 262
 263 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 264    into a "pid" (which may be overloaded with extra thread information).  */
 265 extern ptid_t thread_id_to_pid (int);
 266
 267 /* Translate a 'pid' (which may be overloaded with extra thread information)
 268    into the integer thread id (GDB's homegrown id, not the system's).  */
 269 extern int pid_to_thread_id (ptid_t ptid);
 270
 271 /* Boolean test for an already-known pid (which may be overloaded with
 272    extra thread information).  */
 273 extern int in_thread_list (ptid_t ptid);
 274
 275 /* Boolean test for an already-known thread id (GDB's homegrown id,
 276    not the system's).  */
 277 extern int valid_thread_id (int thread);
 278
 279 /* Search function to lookup a thread by 'pid'.  */
 280 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 281
 282 /* Find thread by GDB user-visible thread number.  */
 283 struct thread_info *find_thread_id (int num);
 284
 285 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 286    returns the first thread in the list.  */
 287 struct thread_info *first_thread_of_process (int pid);
 288
 289 /* Returns any thread of process PID.  */
 290 extern struct thread_info *any_thread_of_process (int pid);
 291
 292 /* Returns any non-exited thread of process PID, giving preference for
 293    not executing threads.  */
 294 extern struct thread_info *any_live_thread_of_process (int pid);
 295
 296 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 297 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 298
 299 /* Iterator function to call a user-provided callback function
 300    once for each known thread.  */
 301 typedef int (*thread_callback_func) (struct thread_info *, void *);
 302 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 303
 304 /* Traverse all threads.  */
 305
 306 #define ALL_THREADS(T)                          \
 307   for (T = thread_list; T; T = T->next)
 308
 309 extern int thread_count (void);
 310
 311 /* Switch from one thread to another.  */
 312 extern void switch_to_thread (ptid_t ptid);
 313
 314 /* Marks thread PTID is running, or stopped.
 315    If PIDGET (PTID) is -1, marks all threads.  */
 316 extern void set_running (ptid_t ptid, int running);
 317
 318 /* Marks or clears thread(s) PTID as having been requested to stop.
 319    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 320    ptid_is_pid(PTID) is true, applies to all threads of the process
 321    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 322    observer is called with PTID as argument.  */
 323 extern void set_stop_requested (ptid_t ptid, int stop);
 324
 325 /* NOTE: Since the thread state is not a boolean, most times, you do
 326    not want to check it with negation.  If you really want to check if
 327    the thread is stopped,
 328
 329     use (good):
 330
 331      if (is_stopped (ptid))
 332
 333     instead of (bad):
 334
 335      if (!is_running (ptid))
 336
 337    The latter also returns true on exited threads, most likelly not
 338    what you want.  */
 339
 340 /* Reports if in the frontend's perpective, thread PTID is running.  */
 341 extern int is_running (ptid_t ptid);
 342
 343 /* Is this thread listed, but known to have exited?  We keep it listed
 344    (but not visible) until it's safe to delete.  */
 345 extern int is_exited (ptid_t ptid);
 346
 347 /* In the frontend's perpective, is this thread stopped?  */
 348 extern int is_stopped (ptid_t ptid);
 349
 350 /* In the frontend's perpective is there any thread running?  */
 351 extern int any_running (void);
 352
 353 /* Marks thread PTID as executing, or not.  If PIDGET (PTID) is -1,
 354    marks all threads.
 355
 356    Note that this is different from the running state.  See the
 357    description of state and executing fields of struct
 358    thread_info.  */
 359 extern void set_executing (ptid_t ptid, int executing);
 360
 361 /* Reports if thread PTID is executing.  */
 362 extern int is_executing (ptid_t ptid);
 363
 364 /* Merge the executing property of thread PTID over to its thread
 365    state property (frontend running/stopped view).
 366
 367    "not executing" -> "stopped"
 368    "executing"     -> "running"
 369    "exited"        -> "exited"
 370
 371    If PIDGET (PTID) is -1, go over all threads.
 372
 373    Notifications are only emitted if the thread state did change.  */
 374 extern void finish_thread_state (ptid_t ptid);
 375
 376 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 377    registered as a cleanup.  PTID_P points to the ptid_t that is
 378    passed to FINISH_THREAD_STATE.  */
 379 extern void finish_thread_state_cleanup (void *ptid_p);
 380
 381 /* Commands with a prefix of `thread'.  */
 382 extern struct cmd_list_element *thread_cmd_list;
 383
 384 /* Print notices on thread events (attach, detach, etc.), set with
 385    `set print thread-events'.  */
 386 extern int print_thread_events;
 387
 388 extern void print_thread_info (struct ui_out *uiout, char *threads,
 389                                int pid);
 390
 391 extern struct cleanup *make_cleanup_restore_current_thread (void);
 392
 393 /* Returns a pointer into the thread_info corresponding to
 394    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 395 extern struct thread_info* inferior_thread (void);
 396
 397 extern void update_thread_list (void);
 398
 399 extern struct thread_info *thread_list;
 400
 401 #endif /* GDBTHREAD_H */