gdb/gdbthread.h

   1 /* Multi-process/thread control defs for GDB, the GNU debugger.
   2    Copyright (C) 1987-2013 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
  31 /* Frontend view of the thread state.  Possible extensions: stepping,
  32    finishing, until(ling),...  */
  33 enum thread_state
  34 {
  35   THREAD_STOPPED,
  36   THREAD_RUNNING,
  37   THREAD_EXITED,
  38 };
  39
  40 /* Inferior thread specific part of `struct infcall_control_state'.
  41
  42    Inferior process counterpart is `struct inferior_control_state'.  */
  43
  44 struct thread_control_state
  45 {
  46   /* User/external stepping state.  */
  47
  48   /* Step-resume or longjmp-resume breakpoint.  */
  49   struct breakpoint *step_resume_breakpoint;
  50
  51   /* Exception-resume breakpoint.  */
  52   struct breakpoint *exception_resume_breakpoint;
  53
  54   /* Range to single step within.
  55
  56      If this is nonzero, respond to a single-step signal by continuing
  57      to step if the pc is in this range.
  58
  59      If step_range_start and step_range_end are both 1, it means to
  60      step for a single instruction (FIXME: it might clean up
  61      wait_for_inferior in a minor way if this were changed to the
  62      address of the instruction and that address plus one.  But maybe
  63      not).  */
  64   CORE_ADDR step_range_start;   /* Inclusive */
  65   CORE_ADDR step_range_end;     /* Exclusive */
  66
  67   /* Stack frame address as of when stepping command was issued.
  68      This is how we know when we step into a subroutine call, and how
  69      to set the frame for the breakpoint used to step out.  */
  70   struct frame_id step_frame_id;
  71
  72   /* Similarly, the frame ID of the underlying stack frame (skipping
  73      any inlined frames).  */
  74   struct frame_id step_stack_frame_id;
  75
  76   /* Nonzero if we are presently stepping over a breakpoint.
  77
  78      If we hit a breakpoint or watchpoint, and then continue, we need
  79      to single step the current thread with breakpoints disabled, to
  80      avoid hitting the same breakpoint or watchpoint again.  And we
  81      should step just a single thread and keep other threads stopped,
  82      so that other threads don't miss breakpoints while they are
  83      removed.
  84
  85      So, this variable simultaneously means that we need to single
  86      step the current thread, keep other threads stopped, and that
  87      breakpoints should be removed while we step.
  88
  89      This variable is set either:
  90      - in proceed, when we resume inferior on user's explicit request
  91      - in keep_going, if handle_inferior_event decides we need to
  92      step over breakpoint.
  93
  94      The variable is cleared in normal_stop.  The proceed calls
  95      wait_for_inferior, which calls handle_inferior_event in a loop,
  96      and until wait_for_inferior exits, this variable is changed only
  97      by keep_going.  */
  98   int trap_expected;
  99
 100   /* Nonzero if the thread is being proceeded for a "finish" command
 101      or a similar situation when stop_registers should be saved.  */
 102   int proceed_to_finish;
 103
 104   /* Nonzero if the thread is being proceeded for an inferior function
 105      call.  */
 106   int in_infcall;
 107
 108   enum step_over_calls_kind step_over_calls;
 109
 110   /* Nonzero if stopped due to a step command.  */
 111   int stop_step;
 112
 113   /* Chain containing status of breakpoint(s) the thread stopped
 114      at.  */
 115   bpstat stop_bpstat;
 116 };
 117
 118 /* Inferior thread specific part of `struct infcall_suspend_state'.
 119
 120    Inferior process counterpart is `struct inferior_suspend_state'.  */
 121
 122 struct thread_suspend_state
 123 {
 124   /* Last signal that the inferior received (why it stopped).  */
 125   enum gdb_signal stop_signal;
 126 };
 127
 128 struct thread_info
 129 {
 130   struct thread_info *next;
 131   ptid_t ptid;                  /* "Actual process id";
 132                                     In fact, this may be overloaded with
 133                                     kernel thread id, etc.  */
 134   int num;                      /* Convenient handle (GDB thread id) */
 135
 136   /* The name of the thread, as specified by the user.  This is NULL
 137      if the thread does not have a user-given name.  */
 138   char *name;
 139
 140   /* Non-zero means the thread is executing.  Note: this is different
 141      from saying that there is an active target and we are stopped at
 142      a breakpoint, for instance.  This is a real indicator whether the
 143      thread is off and running.  */
 144   int executing;
 145
 146   /* Frontend view of the thread state.  Note that the RUNNING/STOPPED
 147      states are different from EXECUTING.  When the thread is stopped
 148      internally while handling an internal event, like a software
 149      single-step breakpoint, EXECUTING will be false, but running will
 150      still be true.  As a possible future extension, this could turn
 151      into enum { stopped, exited, stepping, finishing, until(ling),
 152      running ... }  */
 153   int state;
 154
 155   /* If this is > 0, then it means there's code out there that relies
 156      on this thread being listed.  Don't delete it from the lists even
 157      if we detect it exiting.  */
 158   int refcount;
 159
 160   /* State of GDB control of inferior thread execution.
 161      See `struct thread_control_state'.  */
 162   struct thread_control_state control;
 163
 164   /* State of inferior thread to restore after GDB is done with an inferior
 165      call.  See `struct thread_suspend_state'.  */
 166   struct thread_suspend_state suspend;
 167
 168   int current_line;
 169   struct symtab *current_symtab;
 170
 171   /* Internal stepping state.  */
 172
 173   /* Record the pc of the thread the last time it stopped.  This is
 174      maintained by proceed and keep_going, and used in
 175      adjust_pc_after_break to distinguish a hardware single-step
 176      SIGTRAP from a breakpoint SIGTRAP.  */
 177   CORE_ADDR prev_pc;
 178
 179   /* Should we step over breakpoint next time keep_going is called?  */
 180   int stepping_over_breakpoint;
 181
 182   /* Set to TRUE if we should finish single-stepping over a breakpoint
 183      after hitting the current step-resume breakpoint.  The context here
 184      is that GDB is to do `next' or `step' while signal arrives.
 185      When stepping over a breakpoint and signal arrives, GDB will attempt
 186      to skip signal handler, so it inserts a step_resume_breakpoint at the
 187      signal return address, and resume inferior.
 188      step_after_step_resume_breakpoint is set to TRUE at this moment in
 189      order to keep GDB in mind that there is still a breakpoint to step over
 190      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 191   int step_after_step_resume_breakpoint;
 192
 193   /* Per-thread command support.  */
 194
 195   /* Pointer to what is left to do for an execution command after the
 196      target stops.  Used only in asynchronous mode, by targets that
 197      support async execution.  Several execution commands use it.  */
 198   struct continuation *continuations;
 199
 200   /* Similar to the above, but used when a single execution command
 201      requires several resume/stop iterations.  Used by the step
 202      command.  */
 203   struct continuation *intermediate_continuations;
 204
 205   /* If stepping, nonzero means step count is > 1 so don't print frame
 206      next time inferior stops if it stops due to stepping.  */
 207   int step_multi;
 208
 209   /* This is used to remember when a fork or vfork event was caught by
 210      a catchpoint, and thus the event is to be followed at the next
 211      resume of the thread, and not immediately.  */
 212   struct target_waitstatus pending_follow;
 213
 214   /* True if this thread has been explicitly requested to stop.  */
 215   int stop_requested;
 216
 217   /* The initiating frame of a nexting operation, used for deciding
 218      which exceptions to intercept.  If it is null_frame_id no
 219      bp_longjmp or bp_exception but longjmp has been caught just for
 220      bp_longjmp_call_dummy.  */
 221   struct frame_id initiating_frame;
 222
 223   /* Private data used by the target vector implementation.  */
 224   struct private_thread_info *private;
 225
 226   /* Function that is called to free PRIVATE.  If this is NULL, then
 227      xfree will be called on PRIVATE.  */
 228   void (*private_dtor) (struct private_thread_info *);
 229 };
 230
 231 /* Create an empty thread list, or empty the existing one.  */
 232 extern void init_thread_list (void);
 233
 234 /* Add a thread to the thread list, print a message
 235    that a new thread is found, and return the pointer to
 236    the new thread.  Caller my use this pointer to
 237    initialize the private thread data.  */
 238 extern struct thread_info *add_thread (ptid_t ptid);
 239
 240 /* Same as add_thread, but does not print a message
 241    about new thread.  */
 242 extern struct thread_info *add_thread_silent (ptid_t ptid);
 243
 244 /* Same as add_thread, and sets the private info.  */
 245 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 246                                                  struct private_thread_info *);
 247
 248 /* Delete an existing thread list entry.  */
 249 extern void delete_thread (ptid_t);
 250
 251 /* Delete an existing thread list entry, and be quiet about it.  Used
 252    after the process this thread having belonged to having already
 253    exited, for example.  */
 254 extern void delete_thread_silent (ptid_t);
 255
 256 /* Delete a step_resume_breakpoint from the thread database.  */
 257 extern void delete_step_resume_breakpoint (struct thread_info *);
 258
 259 /* Delete an exception_resume_breakpoint from the thread database.  */
 260 extern void delete_exception_resume_breakpoint (struct thread_info *);
 261
 262 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 263    into a "pid" (which may be overloaded with extra thread information).  */
 264 extern ptid_t thread_id_to_pid (int);
 265
 266 /* Translate a 'pid' (which may be overloaded with extra thread information)
 267    into the integer thread id (GDB's homegrown id, not the system's).  */
 268 extern int pid_to_thread_id (ptid_t ptid);
 269
 270 /* Boolean test for an already-known pid (which may be overloaded with
 271    extra thread information).  */
 272 extern int in_thread_list (ptid_t ptid);
 273
 274 /* Boolean test for an already-known thread id (GDB's homegrown id,
 275    not the system's).  */
 276 extern int valid_thread_id (int thread);
 277
 278 /* Search function to lookup a thread by 'pid'.  */
 279 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 280
 281 /* Find thread by GDB user-visible thread number.  */
 282 struct thread_info *find_thread_id (int num);
 283
 284 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 285    returns the first thread in the list.  */
 286 struct thread_info *first_thread_of_process (int pid);
 287
 288 /* Returns any thread of process PID.  */
 289 extern struct thread_info *any_thread_of_process (int pid);
 290
 291 /* Returns any non-exited thread of process PID, giving preference for
 292    not executing threads.  */
 293 extern struct thread_info *any_live_thread_of_process (int pid);
 294
 295 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 296 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 297
 298 /* Iterator function to call a user-provided callback function
 299    once for each known thread.  */
 300 typedef int (*thread_callback_func) (struct thread_info *, void *);
 301 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 302
 303 /* Traverse all threads.  */
 304
 305 #define ALL_THREADS(T)                          \
 306   for (T = thread_list; T; T = T->next)
 307
 308 extern int thread_count (void);
 309
 310 /* Switch from one thread to another.  */
 311 extern void switch_to_thread (ptid_t ptid);
 312
 313 /* Marks thread PTID is running, or stopped.
 314    If PIDGET (PTID) is -1, marks all threads.  */
 315 extern void set_running (ptid_t ptid, int running);
 316
 317 /* Marks or clears thread(s) PTID as having been requested to stop.
 318    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 319    ptid_is_pid(PTID) is true, applies to all threads of the process
 320    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 321    observer is called with PTID as argument.  */
 322 extern void set_stop_requested (ptid_t ptid, int stop);
 323
 324 /* NOTE: Since the thread state is not a boolean, most times, you do
 325    not want to check it with negation.  If you really want to check if
 326    the thread is stopped,
 327
 328     use (good):
 329
 330      if (is_stopped (ptid))
 331
 332     instead of (bad):
 333
 334      if (!is_running (ptid))
 335
 336    The latter also returns true on exited threads, most likelly not
 337    what you want.  */
 338
 339 /* Reports if in the frontend's perpective, thread PTID is running.  */
 340 extern int is_running (ptid_t ptid);
 341
 342 /* Is this thread listed, but known to have exited?  We keep it listed
 343    (but not visible) until it's safe to delete.  */
 344 extern int is_exited (ptid_t ptid);
 345
 346 /* In the frontend's perpective, is this thread stopped?  */
 347 extern int is_stopped (ptid_t ptid);
 348
 349 /* In the frontend's perpective is there any thread running?  */
 350 extern int any_running (void);
 351
 352 /* Marks thread PTID as executing, or not.  If PIDGET (PTID) is -1,
 353    marks all threads.
 354
 355    Note that this is different from the running state.  See the
 356    description of state and executing fields of struct
 357    thread_info.  */
 358 extern void set_executing (ptid_t ptid, int executing);
 359
 360 /* Reports if thread PTID is executing.  */
 361 extern int is_executing (ptid_t ptid);
 362
 363 /* Merge the executing property of thread PTID over to its thread
 364    state property (frontend running/stopped view).
 365
 366    "not executing" -> "stopped"
 367    "executing"     -> "running"
 368    "exited"        -> "exited"
 369
 370    If PIDGET (PTID) is -1, go over all threads.
 371
 372    Notifications are only emitted if the thread state did change.  */
 373 extern void finish_thread_state (ptid_t ptid);
 374
 375 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 376    registered as a cleanup.  PTID_P points to the ptid_t that is
 377    passed to FINISH_THREAD_STATE.  */
 378 extern void finish_thread_state_cleanup (void *ptid_p);
 379
 380 /* Commands with a prefix of `thread'.  */
 381 extern struct cmd_list_element *thread_cmd_list;
 382
 383 /* Print notices on thread events (attach, detach, etc.), set with
 384    `set print thread-events'.  */
 385 extern int print_thread_events;
 386
 387 extern void print_thread_info (struct ui_out *uiout, char *threads,
 388                                int pid);
 389
 390 extern struct cleanup *make_cleanup_restore_current_thread (void);
 391
 392 /* Returns a pointer into the thread_info corresponding to
 393    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 394 extern struct thread_info* inferior_thread (void);
 395
 396 extern void update_thread_list (void);
 397
 398 extern struct thread_info *thread_list;
 399
 400 #endif /* GDBTHREAD_H */