helgrind/hg_lock_n_thread.h

   1
   2 /*--------------------------------------------------------------------*/
   3 /*--- Definitions for Locks and Threads.                           ---*/
   4 /*---                                           hg_lock_n_thread.h ---*/
   5 /*--------------------------------------------------------------------*/
   6
   7 /*
   8    This file is part of Helgrind, a Valgrind tool for detecting errors
   9    in threaded programs.
  10
  11    Copyright (C) 2007-2017 OpenWorks Ltd
  12       info@open-works.co.uk
  13
  14    This program is free software; you can redistribute it and/or
  15    modify it under the terms of the GNU General Public License as
  16    published by the Free Software Foundation; either version 2 of the
  17    License, or (at your option) any later version.
  18
  19    This program is distributed in the hope that it will be useful, but
  20    WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22    General Public License for more details.
  23
  24    You should have received a copy of the GNU General Public License
  25    along with this program; if not, write to the Free Software
  26    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  27    02111-1307, USA.
  28
  29    The GNU General Public License is contained in the file COPYING.
  30 */
  31
  32 #ifndef __HG_LOCK_N_THREAD_H
  33 #define __HG_LOCK_N_THREAD_H
  34
  35
  36 /*----------------------------------------------------------------*/
  37 /*--- Primary data definitions                                 ---*/
  38 /*----------------------------------------------------------------*/
  39
  40 /* Magic numbers, for doing assertions that structures really are of
  41    the right type.  Useful as some of the code can get a bit
  42    complex. */
  43 #define Thread_MAGIC   0x504fc5e5
  44 #define LockN_MAGIC    0x6545b557 /* normal nonpersistent locks */
  45 #define LockP_MAGIC    0x755b5456 /* persistent (copied) locks */
  46
  47
  48 /* These are handles for Word sets.  CONSTRAINTS: must be small ints
  49    numbered from zero, since 32-bit versions of them are used to
  50    encode lock-sets in libhb's history records (Thr_n_RCEC). */
  51 typedef  WordSet  WordSetID;
  52
  53
  54 /* Synchronisation Objects, exported abstractly by libhb. */
  55 typedef  struct _SO  SO;
  56
  57 /* Thr, libhb's private thread record, exported abstractly.  Thr's are
  58    allocated and never deallocated (simply leaked).  Also ThrID, which
  59    is a small integer which uniquely identifies a Thr and which is
  60    used in ScalarTS because it is smaller than a Thr*.  There is a 1-1
  61    mapping between Thr's and ThrIDs. */
  62 typedef  struct _Thr  Thr;
  63 typedef  UInt         ThrID;
  64
  65
  66 /* Stores information about a thread.  Addresses of these also serve
  67    as unique thread identifiers and so are never freed, so they should
  68    be as small as possible.  Freeing Thread structures makes the
  69    storage management just too complex, and most programs don't create
  70    many threads, so tolerating this leak seems like a not-bad
  71    tradeoff.
  72
  73    Since these are never freed, the .coretid field only indicates the
  74    core's ThreadId associated with this Thread whilst it is alive.
  75    Once the thread finishes, the ThreadId is set to
  76    VG_INVALID_THREADID.
  77
  78    The core may later re-use the same ThreadId for what is a logically
  79    completely different thread, which of course must have a different
  80    Thread structure. */
  81 typedef
  82    struct _Thread {
  83       /* ADMIN */
  84       struct _Thread* admin;
  85       UInt            magic;
  86       Thr*            hbthr; /* which in turn points back here .. */
  87       ThreadId        coretid;  /* .. via its hgthread field */
  88       /* USEFUL */
  89       WordSetID locksetA; /* WordSet of Lock* currently held by thread */
  90       WordSetID locksetW; /* subset of locksetA held in w-mode */
  91       /* EXPOSITION */
  92       /* Place where parent was when this thread was created. */
  93       ExeContext* created_at;
  94       Bool        announced;
  95       /* != 0 if SP fixup needed for unwind : it contains a delta SP value
  96          to use when evh__mem_help_c(read|write)_X is called in the
  97          'middle of an instruction' (e.g. in a push)
  98          after the SP was changed, but before the push has been completed. */
  99       Word        first_sp_delta;
 100       /* Index for generating references in error messages. */
 101       Int         errmsg_index;
 102
 103       /* Nesting level of pthread_create(). New memory allocated is untracked
 104          when this value is > 0: race reporting is suppressed there. DRD does
 105          the same thing implicitly. This is necessary because for example
 106          Solaris libc caches many objects and reuses them for different threads
 107          and that confuses Helgrind. With libvki it would be possible to
 108          explicitly use VG_USERREQ__HG_CLEAN_MEMORY on such objects.
 109          Also mutex activity is ignored so that they do not impose false
 110          ordering between creator and created thread. */
 111       Int pthread_create_nesting_level;
 112
 113       /* Nesting level of synchronization functions called by the client.
 114          Loads and stores are ignored when its value > 0.
 115          Currently this is used solely for suppressing races of primitive
 116          synchronization objects themselves - mutexes, condition variables,
 117          read-write locks and their associated sleep queues.
 118          See also documentation for command line option
 119          --ignore-thread-creation. */
 120       Int synchr_nesting;
 121
 122 #if defined(VGO_solaris)
 123       Int      bind_guard_flag; /* Bind flag from the runtime linker. */
 124 #endif /* VGO_solaris */
 125    }
 126    Thread;
 127
 128 /* Get hg's admin_threads value, so libhb can visit all of them. */
 129 Thread* get_admin_threads ( void );
 130
 131 /* Stores information about a lock's current state.  These are
 132    allocated and later freed (when the containing memory becomes
 133    NoAccess).  This gives a problem for the XError type, which
 134    contains Lock*s.  Solution is to copy any Lock which is to be
 135    incorporated into an XErrors, so as to make it independent from the
 136    'normal' collection of Locks, which can come and go.  When the lock
 137    is copied, its .magic is changed from LockN_Magic to
 138    LockP_Magic. */
 139
 140 /* Lock kinds. */
 141 typedef
 142    enum {
 143       LK_mbRec=1001, /* normal mutex, possibly recursive */
 144       LK_nonRec,     /* normal mutex, definitely non recursive */
 145       LK_rdwr        /* reader-writer lock */
 146    }
 147    LockKind;
 148
 149 typedef
 150    struct _Lock {
 151       /* ADMIN */
 152       struct _Lock* admin_next; /* fields for a double linked */
 153       struct _Lock* admin_prev; /* list of these locks */
 154       ULong         unique; /* used for persistence-hashing */
 155       UInt          magic;  /* LockN_MAGIC or LockP_MAGIC */
 156       /* EXPOSITION */
 157       /* Place where lock first came to the attention of Helgrind. */
 158       ExeContext*   appeared_at;
 159       /* If the lock is held, place where the lock most recently made
 160          an unlocked->locked transition.  Must be sync'd with .heldBy:
 161          either both NULL or both non-NULL. */
 162       ExeContext*   acquired_at;
 163       /* USEFUL-STATIC */
 164       SO*           hbso;      /* associated SO */
 165       Addr          guestaddr; /* Guest address of lock */
 166       LockKind      kind;      /* what kind of lock this is */
 167       /* USEFUL-DYNAMIC */
 168       Bool          heldW;
 169       WordBag*      heldBy; /* bag of threads that hold this lock */
 170       /* .heldBy is NULL: lock is unheld, and .heldW is meaningless
 171                           but arbitrarily set to False
 172          .heldBy is non-NULL:
 173             .heldW is True:  lock is w-held by threads in heldBy
 174             .heldW is False: lock is r-held by threads in heldBy
 175             Either way, heldBy may not validly be an empty Bag.
 176
 177          for LK_nonRec, r-holdings are not allowed, and w-holdings may
 178          only have sizeTotal(heldBy) == 1
 179
 180          for LK_mbRec, r-holdings are not allowed, and w-holdings may
 181          only have sizeUnique(heldBy) == 1
 182
 183          for LK_rdwr, w-holdings may only have sizeTotal(heldBy) == 1 */
 184    }
 185    Lock;
 186
 187 #define Lock_INVALID  ((Lock*)1UL)
 188
 189 /*----------------------------------------------------------------*/
 190 /*--- Sanity checking                                          ---*/
 191 /*----------------------------------------------------------------*/
 192
 193 Bool HG_(is_sane_Thread)   ( Thread* thr );
 194 Bool HG_(is_sane_LockP)    ( Lock* lock );
 195 Bool HG_(is_sane_LockN)    ( Lock* lock );
 196 Bool HG_(is_sane_LockNorP) ( Lock* lock );
 197
 198
 199 #endif /* ! __HG_LOCK_N_THREAD_H */
 200
 201 /*--------------------------------------------------------------------*/
 202 /*--- end                                       hg_lock_n_thread.h ---*/
 203 /*--------------------------------------------------------------------*/