gdbserver/gdbthread.h

   1 /* Multi-thread control defs for remote server for GDB.
   2    Copyright (C) 1993-2020 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 GDBSERVER_GDBTHREAD_H
  20 #define GDBSERVER_GDBTHREAD_H
  21
  22 #include "gdbsupport/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 /* Find the first thread that matches FILTER for which FUNC returns true.
 127    Return NULL if no thread satisfying these conditions is found.  */
 128
 129 template <typename Func>
 130 static thread_info *
 131 find_thread (ptid_t filter, Func func)
 132 {
 133   return find_thread ([&] (thread_info *thread) {
 134     return thread->id.matches (filter) && func (thread);
 135   });
 136 }
 137
 138 /* Invoke FUNC for each thread.  */
 139
 140 template <typename Func>
 141 static void
 142 for_each_thread (Func func)
 143 {
 144   std::list<thread_info *>::iterator next, cur = all_threads.begin ();
 145
 146   while (cur != all_threads.end ())
 147     {
 148       next = cur;
 149       next++;
 150       func (*cur);
 151       cur = next;
 152     }
 153 }
 154
 155 /* Like the above, but only consider threads with pid PID.  */
 156
 157 template <typename Func>
 158 static void
 159 for_each_thread (int pid, Func func)
 160 {
 161   for_each_thread ([&] (thread_info *thread)
 162     {
 163       if (pid == thread->id.pid ())
 164         func (thread);
 165     });
 166 }
 167
 168 /* Find the a random thread for which FUNC (THREAD) returns true.  If
 169    no entry is found then return NULL.  */
 170
 171 template <typename Func>
 172 static thread_info *
 173 find_thread_in_random (Func func)
 174 {
 175   int count = 0;
 176   int random_selector;
 177
 178   /* First count how many interesting entries we have.  */
 179   for_each_thread ([&] (thread_info *thread) {
 180     if (func (thread))
 181       count++;
 182   });
 183
 184   if (count == 0)
 185     return NULL;
 186
 187   /* Now randomly pick an entry out of those.  */
 188   random_selector = (int)
 189     ((count * (double) rand ()) / (RAND_MAX + 1.0));
 190
 191   thread_info *thread = find_thread ([&] (thread_info *thr_arg) {
 192     return func (thr_arg) && (random_selector-- == 0);
 193   });
 194
 195   gdb_assert (thread != NULL);
 196
 197   return thread;
 198 }
 199
 200 /* Get current thread ID (Linux task ID).  */
 201 #define current_ptid (current_thread->id)
 202
 203 /* Get the ptid of THREAD.  */
 204
 205 static inline ptid_t
 206 ptid_of (const thread_info *thread)
 207 {
 208   return thread->id;
 209 }
 210
 211 /* Get the pid of THREAD.  */
 212
 213 static inline int
 214 pid_of (const thread_info *thread)
 215 {
 216   return thread->id.pid ();
 217 }
 218
 219 /* Get the lwp of THREAD.  */
 220
 221 static inline long
 222 lwpid_of (const thread_info *thread)
 223 {
 224   return thread->id.lwp ();
 225 }
 226
 227 #endif /* GDBSERVER_GDBTHREAD_H */