gdbsupport/ptid.h

   1 /* The ptid_t type and common functions operating on it.
   2
   3    Copyright (C) 1986-2020 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef COMMON_PTID_H
  21 #define COMMON_PTID_H
  22
  23 /* The ptid struct is a collection of the various "ids" necessary for
  24    identifying the inferior process/thread being debugged.  This
  25    consists of the process id (pid), lightweight process id (lwp) and
  26    thread id (tid).  When manipulating ptids, the constructors,
  27    accessors, and predicates declared in this file should be used.  Do
  28    NOT access the struct ptid members directly.
  29
  30    process_stratum targets that handle threading themselves should
  31    prefer using the ptid.lwp field, leaving the ptid.tid field for any
  32    thread_stratum target that might want to sit on top.
  33 */
  34
  35 class ptid_t
  36 {
  37 public:
  38   /* Must have a trivial defaulted default constructor so that the
  39      type remains POD.  */
  40   ptid_t () noexcept = default;
  41
  42   /* Make a ptid given the necessary PID, LWP, and TID components.
  43
  44      A ptid with only a PID (LWP and TID equal to zero) is usually used to
  45      represent a whole process, including all its lwps/threads.  */
  46
  47   explicit constexpr ptid_t (int pid, long lwp = 0, long tid = 0)
  48     : m_pid (pid), m_lwp (lwp), m_tid (tid)
  49   {}
  50
  51   /* Fetch the pid (process id) component from the ptid.  */
  52
  53   constexpr int pid () const
  54   { return m_pid; }
  55
  56   /* Return true if the ptid's lwp member is non-zero.  */
  57
  58   constexpr bool lwp_p () const
  59   { return m_lwp != 0; }
  60
  61   /* Fetch the lwp (lightweight process) component from the ptid.  */
  62
  63   constexpr long lwp () const
  64   { return m_lwp; }
  65
  66   /* Return true if the ptid's tid member is non-zero.  */
  67
  68   constexpr bool tid_p () const
  69   { return m_tid != 0; }
  70
  71   /* Fetch the tid (thread id) component from a ptid.  */
  72
  73   constexpr long tid () const
  74   { return m_tid; }
  75
  76   /* Return true if the ptid represents a whole process, including all its
  77      lwps/threads.  Such ptids have the form of (pid, 0, 0), with
  78      pid != -1.  */
  79
  80   constexpr bool is_pid () const
  81   {
  82     return (*this != make_null ()
  83             && *this != make_minus_one ()
  84             && m_lwp == 0
  85             && m_tid == 0);
  86   }
  87
  88   /* Compare two ptids to see if they are equal.  */
  89
  90   constexpr bool operator== (const ptid_t &other) const
  91   {
  92     return (m_pid == other.m_pid
  93             && m_lwp == other.m_lwp
  94             && m_tid == other.m_tid);
  95   }
  96
  97   /* Compare two ptids to see if they are different.  */
  98
  99   constexpr bool operator!= (const ptid_t &other) const
 100   {
 101     return !(*this == other);
 102   }
 103
 104   /* Return true if the ptid matches FILTER.  FILTER can be the wild
 105      card MINUS_ONE_PTID (all ptids match it); can be a ptid representing
 106      a process (ptid.is_pid () returns true), in which case, all lwps and
 107      threads of that given process match, lwps and threads of other
 108      processes do not; or, it can represent a specific thread, in which
 109      case, only that thread will match true.  The ptid must represent a
 110      specific LWP or THREAD, it can never be a wild card.  */
 111
 112   constexpr bool matches (const ptid_t &filter) const
 113   {
 114     return (/* If filter represents any ptid, it's always a match.  */
 115             filter == make_minus_one ()
 116             /* If filter is only a pid, any ptid with that pid
 117                matches.  */
 118             || (filter.is_pid () && m_pid == filter.pid ())
 119
 120             /* Otherwise, this ptid only matches if it's exactly equal
 121                to filter.  */
 122             || *this == filter);
 123   }
 124
 125   /* Make a null ptid.  */
 126
 127   static constexpr ptid_t make_null ()
 128   { return ptid_t (0, 0, 0); }
 129
 130   /* Make a minus one ptid.  */
 131
 132   static constexpr ptid_t make_minus_one ()
 133   { return ptid_t (-1, 0, 0); }
 134
 135 private:
 136   /* Process id.  */
 137   int m_pid;
 138
 139   /* Lightweight process id.  */
 140   long m_lwp;
 141
 142   /* Thread id.  */
 143   long m_tid;
 144 };
 145
 146 /* The null or zero ptid, often used to indicate no process. */
 147
 148 extern const ptid_t null_ptid;
 149
 150 /* The (-1,0,0) ptid, often used to indicate either an error condition
 151    or a "don't care" condition, i.e, "run all threads."  */
 152
 153 extern const ptid_t minus_one_ptid;
 154
 155 #endif /* COMMON_PTID_H */