l4/pkg/valgrind/src/valgrind-3.6.0-svn/drd/drd_segment.c

   1 /* -*- mode: C; c-basic-offset: 3; indent-tabs-mode: nil; -*- */
   2 /*
   3   This file is part of drd, a thread error detector.
   4
   5   Copyright (C) 2006-2011 Bart Van Assche <bvanassche@acm.org>.
   6
   7   This program is free software; you can redistribute it and/or
   8   modify it under the terms of the GNU General Public License as
   9   published by the Free Software Foundation; either version 2 of the
  10   License, or (at your option) any later version.
  11
  12   This program is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15   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, write to the Free Software
  19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20   02111-1307, USA.
  21
  22   The GNU General Public License is contained in the file COPYING.
  23 */
  24
  25
  26 #include "drd_error.h"
  27 #include "drd_segment.h"
  28 #include "drd_thread.h"
  29 #include "pub_tool_basics.h"      // Addr, SizeT
  30 #include "pub_tool_libcassert.h"  // tl_assert()
  31 #include "pub_tool_libcbase.h"    // VG_(strlen)()
  32 #include "pub_tool_libcprint.h"   // VG_(printf)()
  33 #include "pub_tool_machine.h"     // VG_(get_SP)()
  34 #include "pub_tool_mallocfree.h"  // VG_(malloc)(), VG_(free)()
  35 #include "pub_tool_threadstate.h" // VG_INVALID_THREADID
  36
  37
  38 /* Local variables. */
  39
  40 static ULong s_segment_merge_count;
  41 static ULong s_segments_created_count;
  42 static ULong s_segments_alive_count;
  43 static ULong s_max_segments_alive_count;
  44 static Bool s_trace_segment;
  45
  46
  47 /* Function definitions. */
  48
  49 /**
  50  * Initialize the memory 'sg' points at.
  51  *
  52  * @note The creator and created thread ID's may be equal.
  53  * @note This function copies the vector clock of thread 'creator', a technique
  54  *   also known as clock snooping. This will only work reliably if the thread
  55  *   that called pthread_create() waits until the created thread has copied
  56  *   the vector clock.
  57  */
  58 static void sg_init(Segment* const sg,
  59                     const DrdThreadId creator,
  60                     const DrdThreadId created)
  61 {
  62    Segment* creator_sg;
  63    ThreadId vg_created = DRD_(DrdThreadIdToVgThreadId)(created);
  64
  65    tl_assert(sg);
  66    tl_assert(creator == DRD_INVALID_THREADID
  67              || DRD_(IsValidDrdThreadId)(creator));
  68
  69    creator_sg = (creator != DRD_INVALID_THREADID
  70                  ? DRD_(thread_get_segment)(creator) : 0);
  71
  72    sg->next = 0;
  73    sg->prev = 0;
  74    sg->tid = created;
  75    sg->refcnt = 1;
  76
  77    if (vg_created != VG_INVALID_THREADID && VG_(get_SP)(vg_created) != 0)
  78       sg->stacktrace = VG_(record_ExeContext)(vg_created, 0);
  79    else
  80       sg->stacktrace = 0;
  81
  82    if (creator_sg)
  83       DRD_(vc_copy)(&sg->vc, &creator_sg->vc);
  84    else
  85       DRD_(vc_init)(&sg->vc, 0, 0);
  86    DRD_(vc_increment)(&sg->vc, created);
  87    DRD_(bm_init)(&sg->bm);
  88
  89    if (s_trace_segment)
  90    {
  91       char* vc;
  92
  93       vc = DRD_(vc_aprint)(&sg->vc);
  94       VG_(message)(Vg_DebugMsg, "New segment for thread %d with vc %s\n",
  95                    created, vc);
  96       VG_(free)(vc);
  97    }
  98 }
  99
 100 /** Deallocate the memory that was allocated by sg_init(). */
 101 static void DRD_(sg_cleanup)(Segment* const sg)
 102 {
 103    tl_assert(sg);
 104    tl_assert(sg->refcnt == 0);
 105
 106    DRD_(vc_cleanup)(&sg->vc);
 107    DRD_(bm_cleanup)(&sg->bm);
 108 }
 109
 110 /** Allocate and initialize a new segment. */
 111 Segment* DRD_(sg_new)(const DrdThreadId creator, const DrdThreadId created)
 112 {
 113    Segment* sg;
 114
 115    s_segments_created_count++;
 116    s_segments_alive_count++;
 117    if (s_max_segments_alive_count < s_segments_alive_count)
 118       s_max_segments_alive_count = s_segments_alive_count;
 119
 120    sg = VG_(malloc)("drd.segment.sn.1", sizeof(*sg));
 121    tl_assert(sg);
 122    sg_init(sg, creator, created);
 123    return sg;
 124 }
 125
 126 static void DRD_(sg_delete)(Segment* const sg)
 127 {
 128    if (DRD_(sg_get_trace)())
 129    {
 130       char* vc;
 131
 132       vc = DRD_(vc_aprint)(&sg->vc);
 133       VG_(message)(Vg_DebugMsg, "Discarding the segment with vector clock %s\n",
 134                    vc);
 135       VG_(free)(vc);
 136    }
 137
 138    s_segments_alive_count--;
 139
 140    tl_assert(sg);
 141    DRD_(sg_cleanup)(sg);
 142    VG_(free)(sg);
 143 }
 144
 145 /** Increment the reference count of the specified segment. */
 146 Segment* DRD_(sg_get)(Segment* const sg)
 147 {
 148    tl_assert(sg);
 149
 150    sg->refcnt++;
 151    return sg;
 152 }
 153
 154 /**
 155  * Decrement the reference count of the specified segment and deallocate the
 156  * segment if the reference count became zero.
 157  */
 158 void DRD_(sg_put)(Segment* const sg)
 159 {
 160    if (sg == 0)
 161       return;
 162
 163    if (s_trace_segment)
 164    {
 165       char* vc;
 166
 167       vc = DRD_(vc_aprint)(&sg->vc);
 168       VG_(message)(Vg_DebugMsg,
 169                    "Decrementing segment reference count %d -> %d with vc %s\n",
 170                    sg->refcnt, sg->refcnt - 1, vc);
 171       VG_(free)(vc);
 172    }
 173
 174    tl_assert(sg->refcnt >= 1);
 175
 176    if (--sg->refcnt == 0)
 177    {
 178       DRD_(sg_delete)(sg);
 179    }
 180 }
 181
 182 /** Merge sg1 and sg2 into sg1. */
 183 void DRD_(sg_merge)(Segment* const sg1, Segment* const sg2)
 184 {
 185    tl_assert(sg1);
 186    tl_assert(sg1->refcnt == 1);
 187    tl_assert(sg2);
 188    tl_assert(sg2->refcnt == 1);
 189
 190    if (s_trace_segment)
 191    {
 192       char *vc1, *vc2;
 193
 194       vc1 = DRD_(vc_aprint)(&sg1->vc);
 195       vc2 = DRD_(vc_aprint)(&sg2->vc);
 196
 197       VG_(message)(Vg_DebugMsg,
 198                    "Merging segments with vector clocks %s and %s\n", vc1, vc2);
 199       VG_(free)(vc1);
 200       VG_(free)(vc2);
 201    }
 202
 203    s_segment_merge_count++;
 204
 205    // Keep sg1->stacktrace.
 206    // Keep sg1->vc.
 207    // Merge sg2->bm into sg1->bm.
 208    DRD_(bm_merge2)(&sg1->bm, &sg2->bm);
 209 }
 210
 211 /** Print the vector clock and the bitmap of the specified segment. */
 212 void DRD_(sg_print)(Segment* const sg)
 213 {
 214    tl_assert(sg);
 215    VG_(printf)("vc: ");
 216    DRD_(vc_print)(&sg->vc);
 217    VG_(printf)("\n");
 218    DRD_(bm_print)(&sg->bm);
 219 }
 220
 221 /** Query whether segment tracing has been enabled. */
 222 Bool DRD_(sg_get_trace)(void)
 223 {
 224    return s_trace_segment;
 225 }
 226
 227 /** Enable or disable segment tracing. */
 228 void DRD_(sg_set_trace)(Bool const trace_segment)
 229 {
 230    tl_assert(trace_segment == False || trace_segment == True);
 231    s_trace_segment = trace_segment;
 232 }
 233
 234 ULong DRD_(sg_get_segments_created_count)(void)
 235 {
 236    return s_segments_created_count;
 237 }
 238
 239 ULong DRD_(sg_get_segments_alive_count)(void)
 240 {
 241    return s_segments_alive_count;
 242 }
 243
 244 ULong DRD_(sg_get_max_segments_alive_count)(void)
 245 {
 246    return s_max_segments_alive_count;
 247 }
 248
 249 ULong DRD_(sg_get_segment_merge_count)(void)
 250 {
 251    return s_segment_merge_count;
 252 }