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       /* Index for generating references in error messages. */
  96       Int         errmsg_index;
  97
  98       /* Nesting level of pthread_create(). New memory allocated is untracked
  99          when this value is > 0: race reporting is suppressed there. DRD does
 100          the same thing implicitly. This is necessary because for example
 101          Solaris libc caches many objects and reuses them for different threads
 102          and that confuses Helgrind. With libvki it would be possible to
 103          explicitly use VG_USERREQ__HG_CLEAN_MEMORY on such objects.
 104          Also mutex activity is ignored so that they do not impose false
 105          ordering between creator and created thread. */
 106       Int pthread_create_nesting_level;
 107
 108       /* Nesting level of synchronization functions called by the client.
 109          Loads and stores are ignored when its value > 0.
 110          Currently this is used solely for suppressing races of primitive
 111          synchronization objects themselves - mutexes, condition variables,
 112          read-write locks and their associated sleep queues.
 113          See also documentation for command line option
 114          --ignore-thread-creation. */
 115       Int synchr_nesting;
 116
 117 #if defined(VGO_solaris)
 118       Int      bind_guard_flag; /* Bind flag from the runtime linker. */
 119 #endif /* VGO_solaris */
 120    }
 121    Thread;
 122
 123 /* Get hg's admin_threads value, so libhb can visit all of them. */
 124 Thread* get_admin_threads ( void );
 125
 126 /* Stores information about a lock's current state.  These are
 127    allocated and later freed (when the containing memory becomes
 128    NoAccess).  This gives a problem for the XError type, which
 129    contains Lock*s.  Solution is to copy any Lock which is to be
 130    incorporated into an XErrors, so as to make it independent from the
 131    'normal' collection of Locks, which can come and go.  When the lock
 132    is copied, its .magic is changed from LockN_Magic to
 133    LockP_Magic. */
 134
 135 /* Lock kinds. */
 136 typedef
 137    enum {
 138       LK_mbRec=1001, /* normal mutex, possibly recursive */
 139       LK_nonRec,     /* normal mutex, definitely non recursive */
 140       LK_rdwr        /* reader-writer lock */
 141    }
 142    LockKind;
 143
 144 typedef
 145    struct _Lock {
 146       /* ADMIN */
 147       struct _Lock* admin_next; /* fields for a double linked */
 148       struct _Lock* admin_prev; /* list of these locks */
 149       ULong         unique; /* used for persistence-hashing */
 150       UInt          magic;  /* LockN_MAGIC or LockP_MAGIC */
 151       /* EXPOSITION */
 152       /* Place where lock first came to the attention of Helgrind. */
 153       ExeContext*   appeared_at;
 154       /* If the lock is held, place where the lock most recently made
 155          an unlocked->locked transition.  Must be sync'd with .heldBy:
 156          either both NULL or both non-NULL. */
 157       ExeContext*   acquired_at;
 158       /* USEFUL-STATIC */
 159       SO*           hbso;      /* associated SO */
 160       Addr          guestaddr; /* Guest address of lock */
 161       LockKind      kind;      /* what kind of lock this is */
 162       /* USEFUL-DYNAMIC */
 163       Bool          heldW;
 164       WordBag*      heldBy; /* bag of threads that hold this lock */
 165       /* .heldBy is NULL: lock is unheld, and .heldW is meaningless
 166                           but arbitrarily set to False
 167          .heldBy is non-NULL:
 168             .heldW is True:  lock is w-held by threads in heldBy
 169             .heldW is False: lock is r-held by threads in heldBy
 170             Either way, heldBy may not validly be an empty Bag.
 171
 172          for LK_nonRec, r-holdings are not allowed, and w-holdings may
 173          only have sizeTotal(heldBy) == 1
 174
 175          for LK_mbRec, r-holdings are not allowed, and w-holdings may
 176          only have sizeUnique(heldBy) == 1
 177
 178          for LK_rdwr, w-holdings may only have sizeTotal(heldBy) == 1 */
 179    }
 180    Lock;
 181
 182 #define Lock_INVALID  ((Lock*)1UL)
 183
 184 /*----------------------------------------------------------------*/
 185 /*--- Sanity checking                                          ---*/
 186 /*----------------------------------------------------------------*/
 187
 188 Bool HG_(is_sane_Thread)   ( Thread* thr );
 189 Bool HG_(is_sane_LockP)    ( Lock* lock );
 190 Bool HG_(is_sane_LockN)    ( Lock* lock );
 191 Bool HG_(is_sane_LockNorP) ( Lock* lock );
 192
 193
 194 #endif /* ! __HG_LOCK_N_THREAD_H */
 195
 196 /*--------------------------------------------------------------------*/
 197 /*--- end                                       hg_lock_n_thread.h ---*/
 198 /*--------------------------------------------------------------------*/