gdb/gdbserver/gdbthread.h

   1 /* Multi-thread control defs for remote server for GDB.
   2    Copyright (C) 1993-2017 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef GDB_THREAD_H
  20 #define GDB_THREAD_H
  21
  22 #include "common-gdbthread.h"
  23 #include "inferiors.h"
  24
  25 #include <list>
  26
  27 struct btrace_target_info;
  28 struct regcache;
  29
  30 struct thread_info
  31 {
  32   /* The id of this thread.  */
  33   ptid_t id;
  34
  35   void *target_data;
  36   struct regcache *regcache_data;
  37
  38   /* The last resume GDB requested on this thread.  */
  39   enum resume_kind last_resume_kind;
  40
  41   /* The last wait status reported for this thread.  */
  42   struct target_waitstatus last_status;
  43
  44   /* True if LAST_STATUS hasn't been reported to GDB yet.  */
  45   int status_pending_p;
  46
  47   /* Given `while-stepping', a thread may be collecting data for more
  48      than one tracepoint simultaneously.  E.g.:
  49
  50     ff0001  INSN1 <-- TP1, while-stepping 10 collect $regs
  51     ff0002  INSN2
  52     ff0003  INSN3 <-- TP2, collect $regs
  53     ff0004  INSN4 <-- TP3, while-stepping 10 collect $regs
  54     ff0005  INSN5
  55
  56    Notice that when instruction INSN5 is reached, the while-stepping
  57    actions of both TP1 and TP3 are still being collected, and that TP2
  58    had been collected meanwhile.  The whole range of ff0001-ff0005
  59    should be single-stepped, due to at least TP1's while-stepping
  60    action covering the whole range.
  61
  62    On the other hand, the same tracepoint with a while-stepping action
  63    may be hit by more than one thread simultaneously, hence we can't
  64    keep the current step count in the tracepoint itself.
  65
  66    This is the head of the list of the states of `while-stepping'
  67    tracepoint actions this thread is now collecting; NULL if empty.
  68    Each item in the list holds the current step of the while-stepping
  69    action.  */
  70   struct wstep_state *while_stepping;
  71
  72   /* Branch trace target information for this thread.  */
  73   struct btrace_target_info *btrace;
  74 };
  75
  76 extern std::list<thread_info *> all_threads;
  77
  78 void remove_thread (struct thread_info *thread);
  79 struct thread_info *add_thread (ptid_t ptid, void *target_data);
  80
  81 /* Return a pointer to the first thread, or NULL if there isn't one.  */
  82
  83 struct thread_info *get_first_thread (void);
  84
  85 struct thread_info *find_thread_ptid (ptid_t ptid);
  86
  87 /* Find any thread of the PID process.  Returns NULL if none is
  88    found.  */
  89 struct thread_info *find_any_thread_of_pid (int pid);
  90
  91 /* Find the first thread for which FUNC returns true.  Return NULL if no thread
  92    satisfying FUNC is found.  */
  93
  94 template <typename Func>
  95 static thread_info *
  96 find_thread (Func func)
  97 {
  98   std::list<thread_info *>::iterator next, cur = all_threads.begin ();
  99
 100   while (cur != all_threads.end ())
 101     {
 102       next = cur;
 103       next++;
 104
 105       if (func (*cur))
 106         return *cur;
 107
 108       cur = next;
 109     }
 110
 111   return NULL;
 112 }
 113
 114 /* Like the above, but only consider threads with pid PID.  */
 115
 116 template <typename Func>
 117 static thread_info *
 118 find_thread (int pid, Func func)
 119 {
 120   return find_thread ([&] (thread_info *thread)
 121     {
 122       return thread->id.pid () == pid && func (thread);
 123     });
 124 }
 125
 126 /* Invoke FUNC for each thread.  */
 127
 128 template <typename Func>
 129 static void
 130 for_each_thread (Func func)
 131 {
 132   std::list<thread_info *>::iterator next, cur = all_threads.begin ();
 133
 134   while (cur != all_threads.end ())
 135     {
 136       next = cur;
 137       next++;
 138       func (*cur);
 139       cur = next;
 140     }
 141 }
 142
 143 /* Like the above, but only consider threads with pid PID.  */
 144
 145 template <typename Func>
 146 static void
 147 for_each_thread (int pid, Func func)
 148 {
 149   for_each_thread ([&] (thread_info *thread)
 150     {
 151       if (pid == thread->id.pid ())
 152         func (thread);
 153     });
 154 }
 155
 156 /* Find the a random thread for which FUNC (THREAD) returns true.  If
 157    no entry is found then return NULL.  */
 158
 159 template <typename Func>
 160 static thread_info *
 161 find_thread_in_random (Func func)
 162 {
 163   int count = 0;
 164   int random_selector;
 165
 166   /* First count how many interesting entries we have.  */
 167   for_each_thread ([&] (thread_info *thread) {
 168     if (func (thread))
 169       count++;
 170   });
 171
 172   if (count == 0)
 173     return NULL;
 174
 175   /* Now randomly pick an entry out of those.  */
 176   random_selector = (int)
 177     ((count * (double) rand ()) / (RAND_MAX + 1.0));
 178
 179   thread_info *thread = find_thread ([&] (thread_info *thread) {
 180     return func (thread) && (random_selector-- == 0);
 181   });
 182
 183   gdb_assert (thread != NULL);
 184
 185   return thread;
 186 }
 187
 188 /* Get current thread ID (Linux task ID).  */
 189 #define current_ptid (current_thread->id)
 190
 191 /* Get the ptid of THREAD.  */
 192
 193 static inline ptid_t
 194 ptid_of (const thread_info *thread)
 195 {
 196   return thread->id;
 197 }
 198
 199 /* Get the pid of THREAD.  */
 200
 201 static inline int
 202 pid_of (const thread_info *thread)
 203 {
 204   return thread->id.pid ();
 205 }
 206
 207 /* Get the lwp of THREAD.  */
 208
 209 static inline long
 210 lwpid_of (const thread_info *thread)
 211 {
 212   return thread->id.lwp ();
 213 }
 214
 215 /* Create a cleanup to restore current_thread.  */
 216 struct cleanup *make_cleanup_restore_current_thread (void);
 217
 218 #endif /* GDB_THREAD_H */