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 /* Invoke FUNC for each thread.  */
 115
 116 template <typename Func>
 117 static void
 118 for_each_thread (Func func)
 119 {
 120   std::list<thread_info *>::iterator next, cur = all_threads.begin ();
 121
 122   while (cur != all_threads.end ())
 123     {
 124       next = cur;
 125       next++;
 126       func (*cur);
 127       cur = next;
 128     }
 129 }
 130
 131 /* Find the a random thread for which FUNC (THREAD) returns true.  If
 132    no entry is found then return NULL.  */
 133
 134 template <typename Func>
 135 static thread_info *
 136 find_thread_in_random (Func func)
 137 {
 138   int count = 0;
 139   int random_selector;
 140
 141   /* First count how many interesting entries we have.  */
 142   for_each_thread ([&] (thread_info *thread) {
 143     if (func (thread))
 144       count++;
 145   });
 146
 147   if (count == 0)
 148     return NULL;
 149
 150   /* Now randomly pick an entry out of those.  */
 151   random_selector = (int)
 152     ((count * (double) rand ()) / (RAND_MAX + 1.0));
 153
 154   thread_info *thread = find_thread ([&] (thread_info *thread) {
 155     return func (thread) && (random_selector-- == 0);
 156   });
 157
 158   gdb_assert (thread != NULL);
 159
 160   return thread;
 161 }
 162
 163 /* Get current thread ID (Linux task ID).  */
 164 #define current_ptid (current_thread->id)
 165
 166 /* Get the ptid of THREAD.  */
 167
 168 static inline ptid_t
 169 ptid_of (const thread_info *thread)
 170 {
 171   return thread->id;
 172 }
 173
 174 /* Get the pid of THREAD.  */
 175
 176 static inline int
 177 pid_of (const thread_info *thread)
 178 {
 179   return thread->id.pid ();
 180 }
 181
 182 /* Get the lwp of THREAD.  */
 183
 184 static inline long
 185 lwpid_of (const thread_info *thread)
 186 {
 187   return thread->id.lwp ();
 188 }
 189
 190 /* Create a cleanup to restore current_thread.  */
 191 struct cleanup *make_cleanup_restore_current_thread (void);
 192
 193 #endif /* GDB_THREAD_H */