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 #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
 127 /* Inferior thread specific part of `struct infcall_suspend_state'.
 128
 129    Inferior process counterpart is `struct inferior_suspend_state'.  */
 130
 131 struct thread_suspend_state
 132 {
 133   /* Last signal that the inferior received (why it stopped).  */
 134   enum gdb_signal stop_signal;
 135 };
 136
 137 struct thread_info
 138 {
 139   struct thread_info *next;
 140   ptid_t ptid;                  /* "Actual process id";
 141                                     In fact, this may be overloaded with
 142                                     kernel thread id, etc.  */
 143   int num;                      /* Convenient handle (GDB thread id) */
 144
 145   /* The name of the thread, as specified by the user.  This is NULL
 146      if the thread does not have a user-given name.  */
 147   char *name;
 148
 149   /* Non-zero means the thread is executing.  Note: this is different
 150      from saying that there is an active target and we are stopped at
 151      a breakpoint, for instance.  This is a real indicator whether the
 152      thread is off and running.  */
 153   int executing;
 154
 155   /* Frontend view of the thread state.  Note that the RUNNING/STOPPED
 156      states are different from EXECUTING.  When the thread is stopped
 157      internally while handling an internal event, like a software
 158      single-step breakpoint, EXECUTING will be false, but running will
 159      still be true.  As a possible future extension, this could turn
 160      into enum { stopped, exited, stepping, finishing, until(ling),
 161      running ... }  */
 162   int state;
 163
 164   /* If this is > 0, then it means there's code out there that relies
 165      on this thread being listed.  Don't delete it from the lists even
 166      if we detect it exiting.  */
 167   int refcount;
 168
 169   /* State of GDB control of inferior thread execution.
 170      See `struct thread_control_state'.  */
 171   struct thread_control_state control;
 172
 173   /* State of inferior thread to restore after GDB is done with an inferior
 174      call.  See `struct thread_suspend_state'.  */
 175   struct thread_suspend_state suspend;
 176
 177   int current_line;
 178   struct symtab *current_symtab;
 179
 180   /* Internal stepping state.  */
 181
 182   /* Record the pc of the thread the last time it stopped.  This is
 183      maintained by proceed and keep_going, and used in
 184      adjust_pc_after_break to distinguish a hardware single-step
 185      SIGTRAP from a breakpoint SIGTRAP.  */
 186   CORE_ADDR prev_pc;
 187
 188   /* Should we step over breakpoint next time keep_going is called?  */
 189   int stepping_over_breakpoint;
 190
 191   /* Set to TRUE if we should finish single-stepping over a breakpoint
 192      after hitting the current step-resume breakpoint.  The context here
 193      is that GDB is to do `next' or `step' while signal arrives.
 194      When stepping over a breakpoint and signal arrives, GDB will attempt
 195      to skip signal handler, so it inserts a step_resume_breakpoint at the
 196      signal return address, and resume inferior.
 197      step_after_step_resume_breakpoint is set to TRUE at this moment in
 198      order to keep GDB in mind that there is still a breakpoint to step over
 199      when GDB gets back SIGTRAP from step_resume_breakpoint.  */
 200   int step_after_step_resume_breakpoint;
 201
 202   /* Per-thread command support.  */
 203
 204   /* Pointer to what is left to do for an execution command after the
 205      target stops.  Used only in asynchronous mode, by targets that
 206      support async execution.  Several execution commands use it.  */
 207   struct continuation *continuations;
 208
 209   /* Similar to the above, but used when a single execution command
 210      requires several resume/stop iterations.  Used by the step
 211      command.  */
 212   struct continuation *intermediate_continuations;
 213
 214   /* If stepping, nonzero means step count is > 1 so don't print frame
 215      next time inferior stops if it stops due to stepping.  */
 216   int step_multi;
 217
 218   /* This is used to remember when a fork or vfork event was caught by
 219      a catchpoint, and thus the event is to be followed at the next
 220      resume of the thread, and not immediately.  */
 221   struct target_waitstatus pending_follow;
 222
 223   /* True if this thread has been explicitly requested to stop.  */
 224   int stop_requested;
 225
 226   /* The initiating frame of a nexting operation, used for deciding
 227      which exceptions to intercept.  If it is null_frame_id no
 228      bp_longjmp or bp_exception but longjmp has been caught just for
 229      bp_longjmp_call_dummy.  */
 230   struct frame_id initiating_frame;
 231
 232   /* Private data used by the target vector implementation.  */
 233   struct private_thread_info *private;
 234
 235   /* Function that is called to free PRIVATE.  If this is NULL, then
 236      xfree will be called on PRIVATE.  */
 237   void (*private_dtor) (struct private_thread_info *);
 238
 239   /* Branch trace information for this thread.  */
 240   struct btrace_thread_info btrace;
 241 };
 242
 243 /* Create an empty thread list, or empty the existing one.  */
 244 extern void init_thread_list (void);
 245
 246 /* Add a thread to the thread list, print a message
 247    that a new thread is found, and return the pointer to
 248    the new thread.  Caller my use this pointer to
 249    initialize the private thread data.  */
 250 extern struct thread_info *add_thread (ptid_t ptid);
 251
 252 /* Same as add_thread, but does not print a message
 253    about new thread.  */
 254 extern struct thread_info *add_thread_silent (ptid_t ptid);
 255
 256 /* Same as add_thread, and sets the private info.  */
 257 extern struct thread_info *add_thread_with_info (ptid_t ptid,
 258                                                  struct private_thread_info *);
 259
 260 /* Delete an existing thread list entry.  */
 261 extern void delete_thread (ptid_t);
 262
 263 /* Delete an existing thread list entry, and be quiet about it.  Used
 264    after the process this thread having belonged to having already
 265    exited, for example.  */
 266 extern void delete_thread_silent (ptid_t);
 267
 268 /* Delete a step_resume_breakpoint from the thread database.  */
 269 extern void delete_step_resume_breakpoint (struct thread_info *);
 270
 271 /* Delete an exception_resume_breakpoint from the thread database.  */
 272 extern void delete_exception_resume_breakpoint (struct thread_info *);
 273
 274 /* Translate the integer thread id (GDB's homegrown id, not the system's)
 275    into a "pid" (which may be overloaded with extra thread information).  */
 276 extern ptid_t thread_id_to_pid (int);
 277
 278 /* Translate a 'pid' (which may be overloaded with extra thread information)
 279    into the integer thread id (GDB's homegrown id, not the system's).  */
 280 extern int pid_to_thread_id (ptid_t ptid);
 281
 282 /* Boolean test for an already-known pid (which may be overloaded with
 283    extra thread information).  */
 284 extern int in_thread_list (ptid_t ptid);
 285
 286 /* Boolean test for an already-known thread id (GDB's homegrown id,
 287    not the system's).  */
 288 extern int valid_thread_id (int thread);
 289
 290 /* Search function to lookup a thread by 'pid'.  */
 291 extern struct thread_info *find_thread_ptid (ptid_t ptid);
 292
 293 /* Find thread by GDB user-visible thread number.  */
 294 struct thread_info *find_thread_id (int num);
 295
 296 /* Finds the first thread of the inferior given by PID.  If PID is -1,
 297    returns the first thread in the list.  */
 298 struct thread_info *first_thread_of_process (int pid);
 299
 300 /* Returns any thread of process PID.  */
 301 extern struct thread_info *any_thread_of_process (int pid);
 302
 303 /* Returns any non-exited thread of process PID, giving preference for
 304    not executing threads.  */
 305 extern struct thread_info *any_live_thread_of_process (int pid);
 306
 307 /* Change the ptid of thread OLD_PTID to NEW_PTID.  */
 308 void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
 309
 310 /* Iterator function to call a user-provided callback function
 311    once for each known thread.  */
 312 typedef int (*thread_callback_func) (struct thread_info *, void *);
 313 extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
 314
 315 /* Traverse all threads.  */
 316
 317 #define ALL_THREADS(T)                          \
 318   for (T = thread_list; T; T = T->next)
 319
 320 extern int thread_count (void);
 321
 322 /* Switch from one thread to another.  */
 323 extern void switch_to_thread (ptid_t ptid);
 324
 325 /* Marks thread PTID is running, or stopped.
 326    If ptid_get_pid (PTID) is -1, marks all threads.  */
 327 extern void set_running (ptid_t ptid, int running);
 328
 329 /* Marks or clears thread(s) PTID as having been requested to stop.
 330    If PTID is MINUS_ONE_PTID, applies to all threads.  If
 331    ptid_is_pid(PTID) is true, applies to all threads of the process
 332    pointed at by PTID.  If STOP, then the THREAD_STOP_REQUESTED
 333    observer is called with PTID as argument.  */
 334 extern void set_stop_requested (ptid_t ptid, int stop);
 335
 336 /* NOTE: Since the thread state is not a boolean, most times, you do
 337    not want to check it with negation.  If you really want to check if
 338    the thread is stopped,
 339
 340     use (good):
 341
 342      if (is_stopped (ptid))
 343
 344     instead of (bad):
 345
 346      if (!is_running (ptid))
 347
 348    The latter also returns true on exited threads, most likelly not
 349    what you want.  */
 350
 351 /* Reports if in the frontend's perpective, thread PTID is running.  */
 352 extern int is_running (ptid_t ptid);
 353
 354 /* Is this thread listed, but known to have exited?  We keep it listed
 355    (but not visible) until it's safe to delete.  */
 356 extern int is_exited (ptid_t ptid);
 357
 358 /* In the frontend's perpective, is this thread stopped?  */
 359 extern int is_stopped (ptid_t ptid);
 360
 361 /* In the frontend's perpective is there any thread running?  */
 362 extern int any_running (void);
 363
 364 /* Marks thread PTID as executing, or not.  If ptid_get_pid (PTID) is -1,
 365    marks all threads.
 366
 367    Note that this is different from the running state.  See the
 368    description of state and executing fields of struct
 369    thread_info.  */
 370 extern void set_executing (ptid_t ptid, int executing);
 371
 372 /* Reports if thread PTID is executing.  */
 373 extern int is_executing (ptid_t ptid);
 374
 375 /* Merge the executing property of thread PTID over to its thread
 376    state property (frontend running/stopped view).
 377
 378    "not executing" -> "stopped"
 379    "executing"     -> "running"
 380    "exited"        -> "exited"
 381
 382    If ptid_get_pid (PTID) is -1, go over all threads.
 383
 384    Notifications are only emitted if the thread state did change.  */
 385 extern void finish_thread_state (ptid_t ptid);
 386
 387 /* Same as FINISH_THREAD_STATE, but with an interface suitable to be
 388    registered as a cleanup.  PTID_P points to the ptid_t that is
 389    passed to FINISH_THREAD_STATE.  */
 390 extern void finish_thread_state_cleanup (void *ptid_p);
 391
 392 /* Commands with a prefix of `thread'.  */
 393 extern struct cmd_list_element *thread_cmd_list;
 394
 395 /* Print notices on thread events (attach, detach, etc.), set with
 396    `set print thread-events'.  */
 397 extern int print_thread_events;
 398
 399 extern void print_thread_info (struct ui_out *uiout, char *threads,
 400                                int pid);
 401
 402 extern struct cleanup *make_cleanup_restore_current_thread (void);
 403
 404 /* Returns a pointer into the thread_info corresponding to
 405    INFERIOR_PTID.  INFERIOR_PTID *must* be in the thread list.  */
 406 extern struct thread_info* inferior_thread (void);
 407
 408 extern void update_thread_list (void);
 409
 410 /* Return true if PC is in the stepping range of THREAD.  */
 411
 412 int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
 413
 414 extern struct thread_info *thread_list;
 415
 416 #endif /* GDBTHREAD_H */