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sewardjaf44c822007-11-25 14:01:38 +00001/*
bart86562bd2009-02-16 19:43:56 +00002 This file is part of drd, a thread error detector.
sewardjaf44c822007-11-25 14:01:38 +00003
bartd4bab992013-10-04 05:55:30 +00004 Copyright (C) 2006-2013 Bart Van Assche <bvanassche@acm.org>.
sewardjaf44c822007-11-25 14:01:38 +00005
6 This program is free software; you can redistribute it and/or
7 modify it under the terms of the GNU General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 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, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307, USA.
20
21 The GNU General Public License is contained in the file COPYING.
22*/
23
24
25#ifndef __DRD_VC_H
26#define __DRD_VC_H
27
28
bart41b226c2009-02-14 16:55:19 +000029/*
30 * DRD vector clock implementation:
31 * - One counter per thread.
32 * - A vector clock is implemented as multiple pairs of (thread id, counter).
33 * - Pairs are stored in an array sorted by thread id.
34 *
35 * Semantics:
36 * - Each time a thread performs an action that implies an ordering between
37 * intra-thread events, the counter of that thread is incremented.
38 * - Vector clocks are compared by comparing all counters of all threads.
39 * - When a thread synchronization action is performed that guarantees that
40 * new actions of the current thread are executed after the actions of the
bart31b983d2010-02-21 14:52:59 +000041 * other thread, the vector clock of the synchronization object and the
bart41b226c2009-02-14 16:55:19 +000042 * current thread are combined (by taking the component-wise maximum).
43 * - A vector clock is incremented during actions such as
44 * pthread_create(), pthread_mutex_unlock(), sem_post(). (Actions where
45 * an inter-thread ordering "arrow" starts).
46 */
sewardjaf44c822007-11-25 14:01:38 +000047
48
bart8f822af2009-06-08 18:20:42 +000049#include "pub_tool_basics.h" /* Addr, SizeT */
50#include "drd_basics.h" /* DrdThreadId */
51#include "pub_tool_libcassert.h" /* tl_assert() */
52
53
54#define VC_PREALLOCATED 8
sewardjaf44c822007-11-25 14:01:38 +000055
56
bart41b226c2009-02-14 16:55:19 +000057/** Vector clock element. */
sewardjaf44c822007-11-25 14:01:38 +000058typedef struct
59{
bartbedfd232009-03-26 19:07:15 +000060 DrdThreadId threadid;
61 UInt count;
sewardjaf44c822007-11-25 14:01:38 +000062} VCElem;
63
64typedef struct
65{
bartbedfd232009-03-26 19:07:15 +000066 unsigned capacity; /**< number of elements allocated for array vc. */
67 unsigned size; /**< number of elements used of array vc. */
68 VCElem* vc; /**< vector clock elements. */
bart8f822af2009-06-08 18:20:42 +000069 VCElem preallocated[VC_PREALLOCATED];
sewardjaf44c822007-11-25 14:01:38 +000070} VectorClock;
71
72
bart41b226c2009-02-14 16:55:19 +000073void DRD_(vc_init)(VectorClock* const vc,
74 const VCElem* const vcelem,
75 const unsigned size);
76void DRD_(vc_cleanup)(VectorClock* const vc);
77void DRD_(vc_copy)(VectorClock* const new, const VectorClock* const rhs);
78void DRD_(vc_assign)(VectorClock* const lhs, const VectorClock* const rhs);
bart41b226c2009-02-14 16:55:19 +000079void DRD_(vc_increment)(VectorClock* const vc, DrdThreadId const tid);
bartfa1b2932008-06-22 13:05:00 +000080static __inline__
bart41b226c2009-02-14 16:55:19 +000081Bool DRD_(vc_lte)(const VectorClock* const vc1,
82 const VectorClock* const vc2);
83Bool DRD_(vc_ordered)(const VectorClock* const vc1,
84 const VectorClock* const vc2);
85void DRD_(vc_min)(VectorClock* const result,
86 const VectorClock* const rhs);
87void DRD_(vc_combine)(VectorClock* const result,
88 const VectorClock* const rhs);
bart41b226c2009-02-14 16:55:19 +000089void DRD_(vc_print)(const VectorClock* const vc);
florian19f91bb2012-11-10 22:29:54 +000090HChar* DRD_(vc_aprint)(const VectorClock* const vc);
bart41b226c2009-02-14 16:55:19 +000091void DRD_(vc_check)(const VectorClock* const vc);
92void DRD_(vc_test)(void);
sewardjaf44c822007-11-25 14:01:38 +000093
94
bartfa1b2932008-06-22 13:05:00 +000095
96/**
97 * @return True if all thread id's that are present in vc1 also exist in
98 * vc2, and if additionally all corresponding counters in v2 are higher or
99 * equal.
100 */
101static __inline__
bart41b226c2009-02-14 16:55:19 +0000102Bool DRD_(vc_lte)(const VectorClock* const vc1, const VectorClock* const vc2)
bartfa1b2932008-06-22 13:05:00 +0000103{
bartbedfd232009-03-26 19:07:15 +0000104 unsigned i;
105 unsigned j = 0;
bartfa1b2932008-06-22 13:05:00 +0000106
bartbedfd232009-03-26 19:07:15 +0000107 for (i = 0; i < vc1->size; i++)
108 {
109 while (j < vc2->size && vc2->vc[j].threadid < vc1->vc[i].threadid)
bartbedfd232009-03-26 19:07:15 +0000110 j++;
bartbedfd232009-03-26 19:07:15 +0000111 if (j >= vc2->size || vc2->vc[j].threadid > vc1->vc[i].threadid)
112 return False;
bartfa1b2932008-06-22 13:05:00 +0000113#ifdef ENABLE_DRD_CONSISTENCY_CHECKS
bart468947b2010-03-07 20:00:18 +0000114 /*
115 * This assert statement has been commented out because of performance
116 * reasons.
117 */
bartbedfd232009-03-26 19:07:15 +0000118 tl_assert(j < vc2->size && vc2->vc[j].threadid == vc1->vc[i].threadid);
bartfa1b2932008-06-22 13:05:00 +0000119#endif
bartbedfd232009-03-26 19:07:15 +0000120 if (vc1->vc[i].count > vc2->vc[j].count)
121 return False;
122 }
123 return True;
bartfa1b2932008-06-22 13:05:00 +0000124}
125
126
sewardjaf44c822007-11-25 14:01:38 +0000127#endif /* __DRD_VC_H */