1 /* 2 This file is part of drd, a thread error detector. 3 4 Copyright (C) 2006-2015 Bart Van Assche <bvanassche (at) acm.org>. 5 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 #include "drd_error.h" 26 #include "drd_segment.h" 27 #include "drd_thread.h" 28 #include "pub_tool_basics.h" // Addr, SizeT 29 #include "pub_tool_libcassert.h" // tl_assert() 30 #include "pub_tool_libcbase.h" // VG_(strlen)() 31 #include "pub_tool_libcprint.h" // VG_(printf)() 32 #include "pub_tool_machine.h" // VG_(get_SP)() 33 #include "pub_tool_mallocfree.h" // VG_(malloc)(), VG_(free)() 34 #include "pub_tool_threadstate.h" // VG_INVALID_THREADID 35 36 37 /* Global variables. */ 38 39 Segment* DRD_(g_sg_list); 40 41 42 /* Local variables. */ 43 44 static ULong s_segment_merge_count; 45 static ULong s_segments_created_count; 46 static ULong s_segments_alive_count; 47 static ULong s_max_segments_alive_count; 48 static Bool s_trace_segment; 49 50 51 /* Function definitions. */ 52 53 /** 54 * Initialize the memory 'sg' points at. 55 * 56 * @note The creator and created thread ID's may be equal. 57 * @note This function copies the vector clock of thread 'creator', a technique 58 * also known as clock snooping. This will only work reliably if the thread 59 * that called pthread_create() waits until the created thread has copied 60 * the vector clock. 61 */ 62 static void sg_init(Segment* const sg, 63 const DrdThreadId creator, 64 const DrdThreadId created) 65 { 66 Segment* creator_sg; 67 ThreadId vg_created = DRD_(DrdThreadIdToVgThreadId)(created); 68 69 tl_assert(sg); 70 tl_assert(creator == DRD_INVALID_THREADID 71 || DRD_(IsValidDrdThreadId)(creator)); 72 73 creator_sg = (creator != DRD_INVALID_THREADID 74 ? DRD_(thread_get_segment)(creator) : 0); 75 76 sg->g_next = NULL; 77 sg->g_prev = NULL; 78 sg->thr_next = NULL; 79 sg->thr_prev = NULL; 80 sg->tid = created; 81 sg->refcnt = 1; 82 83 if (vg_created != VG_INVALID_THREADID && VG_(get_SP)(vg_created) != 0) 84 sg->stacktrace = VG_(record_ExeContext)(vg_created, 0); 85 else 86 sg->stacktrace = 0; 87 88 if (creator_sg) 89 DRD_(vc_copy)(&sg->vc, &creator_sg->vc); 90 else 91 DRD_(vc_init)(&sg->vc, 0, 0); 92 DRD_(vc_increment)(&sg->vc, created); 93 DRD_(bm_init)(&sg->bm); 94 95 if (s_trace_segment) 96 { 97 HChar* vc; 98 99 vc = DRD_(vc_aprint)(&sg->vc); 100 VG_(message)(Vg_DebugMsg, "New segment for thread %u with vc %s\n", 101 created, vc); 102 VG_(free)(vc); 103 } 104 } 105 106 /** Deallocate the memory that was allocated by sg_init(). */ 107 static void DRD_(sg_cleanup)(Segment* const sg) 108 { 109 tl_assert(sg); 110 tl_assert(sg->refcnt == 0); 111 112 DRD_(vc_cleanup)(&sg->vc); 113 DRD_(bm_cleanup)(&sg->bm); 114 } 115 116 /** Allocate and initialize a new segment. */ 117 Segment* DRD_(sg_new)(const DrdThreadId creator, const DrdThreadId created) 118 { 119 Segment* sg; 120 121 s_segments_created_count++; 122 s_segments_alive_count++; 123 if (s_max_segments_alive_count < s_segments_alive_count) 124 s_max_segments_alive_count = s_segments_alive_count; 125 126 sg = VG_(malloc)("drd.segment.sn.1", sizeof(*sg)); 127 sg_init(sg, creator, created); 128 if (DRD_(g_sg_list)) { 129 DRD_(g_sg_list)->g_prev = sg; 130 sg->g_next = DRD_(g_sg_list); 131 } 132 DRD_(g_sg_list) = sg; 133 return sg; 134 } 135 136 static void DRD_(sg_delete)(Segment* const sg) 137 { 138 if (DRD_(sg_get_trace)()) 139 { 140 HChar* vc; 141 142 vc = DRD_(vc_aprint)(&sg->vc); 143 VG_(message)(Vg_DebugMsg, "Discarding the segment with vector clock %s\n", 144 vc); 145 VG_(free)(vc); 146 } 147 148 s_segments_alive_count--; 149 150 tl_assert(sg); 151 if (sg->g_next) 152 sg->g_next->g_prev = sg->g_prev; 153 if (sg->g_prev) 154 sg->g_prev->g_next = sg->g_next; 155 else 156 DRD_(g_sg_list) = sg->g_next; 157 DRD_(sg_cleanup)(sg); 158 VG_(free)(sg); 159 } 160 161 /** Increment the reference count of the specified segment. */ 162 Segment* DRD_(sg_get)(Segment* const sg) 163 { 164 tl_assert(sg); 165 166 sg->refcnt++; 167 return sg; 168 } 169 170 /** 171 * Decrement the reference count of the specified segment and deallocate the 172 * segment if the reference count became zero. 173 */ 174 void DRD_(sg_put)(Segment* const sg) 175 { 176 if (sg == 0) 177 return; 178 179 if (s_trace_segment) 180 { 181 HChar* vc; 182 183 vc = DRD_(vc_aprint)(&sg->vc); 184 VG_(message)(Vg_DebugMsg, 185 "Decrementing segment reference count %d -> %d with vc %s\n", 186 sg->refcnt, sg->refcnt - 1, vc); 187 VG_(free)(vc); 188 } 189 190 tl_assert(sg->refcnt >= 1); 191 192 if (--sg->refcnt == 0) 193 { 194 DRD_(sg_delete)(sg); 195 } 196 } 197 198 /** Merge sg1 and sg2 into sg1. */ 199 void DRD_(sg_merge)(Segment* const sg1, Segment* const sg2) 200 { 201 tl_assert(sg1); 202 tl_assert(sg1->refcnt == 1); 203 tl_assert(sg2); 204 tl_assert(sg2->refcnt == 1); 205 206 if (s_trace_segment) 207 { 208 HChar *vc1, *vc2; 209 210 vc1 = DRD_(vc_aprint)(&sg1->vc); 211 vc2 = DRD_(vc_aprint)(&sg2->vc); 212 213 VG_(message)(Vg_DebugMsg, 214 "Merging segments with vector clocks %s and %s\n", vc1, vc2); 215 VG_(free)(vc1); 216 VG_(free)(vc2); 217 } 218 219 s_segment_merge_count++; 220 221 // Keep sg1->stacktrace. 222 // Keep sg1->vc. 223 // Merge sg2->bm into sg1->bm. 224 DRD_(bm_merge2)(&sg1->bm, &sg2->bm); 225 } 226 227 /** Print the vector clock and the bitmap of the specified segment. */ 228 void DRD_(sg_print)(Segment* const sg) 229 { 230 tl_assert(sg); 231 VG_(printf)("vc: "); 232 DRD_(vc_print)(&sg->vc); 233 VG_(printf)("\n"); 234 DRD_(bm_print)(&sg->bm); 235 } 236 237 /** Query whether segment tracing has been enabled. */ 238 Bool DRD_(sg_get_trace)(void) 239 { 240 return s_trace_segment; 241 } 242 243 /** Enable or disable segment tracing. */ 244 void DRD_(sg_set_trace)(Bool const trace_segment) 245 { 246 tl_assert(trace_segment == False || trace_segment == True); 247 s_trace_segment = trace_segment; 248 } 249 250 ULong DRD_(sg_get_segments_created_count)(void) 251 { 252 return s_segments_created_count; 253 } 254 255 ULong DRD_(sg_get_segments_alive_count)(void) 256 { 257 return s_segments_alive_count; 258 } 259 260 ULong DRD_(sg_get_max_segments_alive_count)(void) 261 { 262 return s_max_segments_alive_count; 263 } 264 265 ULong DRD_(sg_get_segment_merge_count)(void) 266 { 267 return s_segment_merge_count; 268 } 269
