src/mc/checker/LivenessChecker.cpp

   1 /* Copyright (c) 2011-2019. The SimGrid Team. All rights reserved.          */
   2
   3 /* This program is free software; you can redistribute it and/or modify it
   4  * under the terms of the license (GNU LGPL) which comes with this package. */
   5
   6 #include "src/mc/checker/LivenessChecker.hpp"
   7 #include "src/mc/Session.hpp"
   8 #include "src/mc/mc_config.hpp"
   9 #include "src/mc/mc_exit.hpp"
  10 #include "src/mc/mc_private.hpp"
  11 #include "src/mc/mc_request.hpp"
  12 #include "src/mc/mc_smx.hpp"
  13
  14 #include <boost/range/algorithm.hpp>
  15 #include <cstring>
  16
  17 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_liveness, mc, "Logging specific to algorithms for liveness properties verification");
  18
  19 /********* Static functions *********/
  20
  21 namespace simgrid {
  22 namespace mc {
  23
  24 VisitedPair::VisitedPair(int pair_num, xbt_automaton_state_t automaton_state,
  25                          std::shared_ptr<const std::vector<int>> atomic_propositions,
  26                          std::shared_ptr<simgrid::mc::State> graph_state)
  27     : num(pair_num), automaton_state(automaton_state)
  28 {
  29   simgrid::mc::RemoteClient* process = &(mc_model_checker->process());
  30
  31   this->graph_state = std::move(graph_state);
  32   if(this->graph_state->system_state == nullptr)
  33     this->graph_state->system_state = std::make_shared<simgrid::mc::Snapshot>(pair_num);
  34   this->heap_bytes_used = mmalloc_get_bytes_used_remote(process->get_heap()->heaplimit, process->get_malloc_info());
  35
  36   this->actors_count = mc_model_checker->process().actors().size();
  37
  38   this->other_num = -1;
  39   this->atomic_propositions = std::move(atomic_propositions);
  40 }
  41
  42 static bool evaluate_label(xbt_automaton_exp_label_t l, std::vector<int> const& values)
  43 {
  44   switch (l->type) {
  45   case xbt_automaton_exp_label::AUT_OR:
  46     return evaluate_label(l->u.or_and.left_exp, values)
  47       || evaluate_label(l->u.or_and.right_exp, values);
  48   case xbt_automaton_exp_label::AUT_AND:
  49     return evaluate_label(l->u.or_and.left_exp, values)
  50       && evaluate_label(l->u.or_and.right_exp, values);
  51   case xbt_automaton_exp_label::AUT_NOT:
  52     return not evaluate_label(l->u.exp_not, values);
  53   case xbt_automaton_exp_label::AUT_PREDICAT:{
  54       unsigned int cursor = 0;
  55       xbt_automaton_propositional_symbol_t p = nullptr;
  56       xbt_dynar_foreach(simgrid::mc::property_automaton->propositional_symbols, cursor, p) {
  57         if (std::strcmp(xbt_automaton_propositional_symbol_get_name(p), l->u.predicat) == 0)
  58           return values[cursor] != 0;
  59       }
  60       xbt_die("Missing predicate");
  61       break;
  62     }
  63   case xbt_automaton_exp_label::AUT_ONE:
  64     return true;
  65   default:
  66     xbt_die("Unexpected vaue for automaton");
  67   }
  68 }
  69
  70 Pair::Pair(unsigned long expanded_pairs) : num(expanded_pairs)
  71 {}
  72
  73 std::shared_ptr<const std::vector<int>> LivenessChecker::get_proposition_values()
  74 {
  75   std::vector<int> values;
  76   unsigned int cursor = 0;
  77   xbt_automaton_propositional_symbol_t ps = nullptr;
  78   xbt_dynar_foreach(simgrid::mc::property_automaton->propositional_symbols, cursor, ps)
  79     values.push_back(xbt_automaton_propositional_symbol_evaluate(ps));
  80   return std::make_shared<const std::vector<int>>(std::move(values));
  81 }
  82
  83 std::shared_ptr<VisitedPair> LivenessChecker::insert_acceptance_pair(simgrid::mc::Pair* pair)
  84 {
  85   std::shared_ptr<VisitedPair> new_pair = std::make_shared<VisitedPair>(
  86     pair->num, pair->automaton_state, pair->atomic_propositions,
  87     pair->graph_state);
  88
  89   auto res = boost::range::equal_range(acceptance_pairs_, new_pair.get(),
  90                                        simgrid::mc::DerefAndCompareByActorsCountAndUsedHeap());
  91
  92   if (pair->search_cycle) for (auto i = res.first; i != res.second; ++i) {
  93     std::shared_ptr<simgrid::mc::VisitedPair> const& pair_test = *i;
  94     if (xbt_automaton_state_compare(pair_test->automaton_state, new_pair->automaton_state) != 0 ||
  95         *(pair_test->atomic_propositions) != *(new_pair->atomic_propositions) ||
  96         not snapshot_equal(pair_test->graph_state->system_state.get(), new_pair->graph_state->system_state.get()))
  97       continue;
  98     XBT_INFO("Pair %d already reached (equal to pair %d) !", new_pair->num, pair_test->num);
  99     exploration_stack_.pop_back();
 100     if (dot_output != nullptr)
 101       fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", this->previous_pair_, pair_test->num,
 102               this->previous_request_.c_str());
 103     return nullptr;
 104   }
 105
 106   acceptance_pairs_.insert(res.first, new_pair);
 107   return new_pair;
 108 }
 109
 110 void LivenessChecker::remove_acceptance_pair(int pair_num)
 111 {
 112   for (auto i = acceptance_pairs_.begin(); i != acceptance_pairs_.end(); ++i)
 113     if ((*i)->num == pair_num) {
 114       acceptance_pairs_.erase(i);
 115       break;
 116     }
 117 }
 118
 119 void LivenessChecker::replay()
 120 {
 121   XBT_DEBUG("**** Begin Replay ****");
 122
 123   /* Intermediate backtracking */
 124   if(_sg_mc_checkpoint > 0) {
 125     simgrid::mc::Pair* pair = exploration_stack_.back().get();
 126     if(pair->graph_state->system_state){
 127       pair->graph_state->system_state->restore(&mc_model_checker->process());
 128       return;
 129     }
 130   }
 131
 132   /* Restore the initial state */
 133   simgrid::mc::session->restore_initial_state();
 134
 135   /* Traverse the stack from the initial state and re-execute the transitions */
 136   int depth = 1;
 137   for (std::shared_ptr<Pair> const& pair : exploration_stack_) {
 138     if (pair == exploration_stack_.back())
 139       break;
 140
 141     std::shared_ptr<State> state = pair->graph_state;
 142
 143     if (pair->exploration_started) {
 144
 145       int req_num             = state->transition_.argument_;
 146       smx_simcall_t saved_req = &state->executed_req_;
 147
 148       smx_simcall_t req = nullptr;
 149
 150       if (saved_req != nullptr) {
 151         /* because we got a copy of the executed request, we have to fetch the
 152              real one, pointed by the request field of the issuer process */
 153         const smx_actor_t issuer = MC_smx_simcall_get_issuer(saved_req);
 154         req = &issuer->simcall;
 155
 156         /* Debug information */
 157         XBT_DEBUG("Replay (depth = %d) : %s (%p)",
 158           depth,
 159           simgrid::mc::request_to_string(
 160             req, req_num, simgrid::mc::RequestType::simix).c_str(),
 161           state.get());
 162       }
 163
 164       this->get_session().execute(state->transition_);
 165     }
 166
 167     /* Update statistics */
 168     visited_pairs_count_++;
 169     mc_model_checker->executed_transitions++;
 170
 171     depth++;
 172
 173   }
 174
 175   XBT_DEBUG("**** End Replay ****");
 176 }
 177
 178 /**
 179  * @brief Checks whether a given pair has already been visited by the algorithm.
 180  */
 181 int LivenessChecker::insert_visited_pair(std::shared_ptr<VisitedPair> visited_pair, simgrid::mc::Pair* pair)
 182 {
 183   if (_sg_mc_max_visited_states == 0)
 184     return -1;
 185
 186   if (visited_pair == nullptr)
 187     visited_pair =
 188         std::make_shared<VisitedPair>(pair->num, pair->automaton_state, pair->atomic_propositions, pair->graph_state);
 189
 190   auto range = boost::range::equal_range(visited_pairs_, visited_pair.get(),
 191                                          simgrid::mc::DerefAndCompareByActorsCountAndUsedHeap());
 192
 193   for (auto i = range.first; i != range.second; ++i) {
 194     VisitedPair* pair_test = i->get();
 195     if (xbt_automaton_state_compare(pair_test->automaton_state, visited_pair->automaton_state) != 0 ||
 196         *(pair_test->atomic_propositions) != *(visited_pair->atomic_propositions) ||
 197         not snapshot_equal(pair_test->graph_state->system_state.get(), visited_pair->graph_state->system_state.get()))
 198       continue;
 199     if (pair_test->other_num == -1)
 200       visited_pair->other_num = pair_test->num;
 201     else
 202       visited_pair->other_num = pair_test->other_num;
 203     if (dot_output == nullptr)
 204       XBT_DEBUG("Pair %d already visited ! (equal to pair %d)", visited_pair->num, pair_test->num);
 205     else
 206       XBT_DEBUG("Pair %d already visited ! (equal to pair %d (pair %d in dot_output))",
 207         visited_pair->num, pair_test->num, visited_pair->other_num);
 208     (*i) = std::move(visited_pair);
 209     return (*i)->other_num;
 210   }
 211
 212   visited_pairs_.insert(range.first, std::move(visited_pair));
 213   this->purge_visited_pairs();
 214   return -1;
 215 }
 216
 217 void LivenessChecker::purge_visited_pairs()
 218 {
 219   if (_sg_mc_max_visited_states != 0 && visited_pairs_.size() > (std::size_t)_sg_mc_max_visited_states) {
 220     // Remove the oldest entry with a linear search:
 221     visited_pairs_.erase(
 222         boost::min_element(visited_pairs_, [](std::shared_ptr<VisitedPair> const a,
 223                                               std::shared_ptr<VisitedPair> const& b) { return a->num < b->num; }));
 224   }
 225 }
 226
 227 LivenessChecker::LivenessChecker(Session& s) : Checker(s)
 228 {
 229 }
 230
 231 RecordTrace LivenessChecker::get_record_trace() // override
 232 {
 233   RecordTrace res;
 234   for (std::shared_ptr<Pair> const& pair : exploration_stack_)
 235     res.push_back(pair->graph_state->get_transition());
 236   return res;
 237 }
 238
 239 void LivenessChecker::log_state() // override
 240 {
 241   XBT_INFO("Expanded pairs = %lu", expanded_pairs_count_);
 242   XBT_INFO("Visited pairs = %lu", visited_pairs_count_);
 243   XBT_INFO("Executed transitions = %lu", mc_model_checker->executed_transitions);
 244 }
 245
 246 void LivenessChecker::show_acceptance_cycle(std::size_t depth)
 247 {
 248   XBT_INFO("*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*");
 249   XBT_INFO("|             ACCEPTANCE CYCLE            |");
 250   XBT_INFO("*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*");
 251   XBT_INFO("Counter-example that violates formula:");
 252   for (auto const& s : this->get_textual_trace())
 253     XBT_INFO("  %s", s.c_str());
 254   simgrid::mc::dumpRecordPath();
 255   simgrid::mc::session->log_state();
 256   XBT_INFO("Counter-example depth: %zu", depth);
 257 }
 258
 259 std::vector<std::string> LivenessChecker::get_textual_trace() // override
 260 {
 261   std::vector<std::string> trace;
 262   for (std::shared_ptr<Pair> const& pair : exploration_stack_) {
 263     int req_num       = pair->graph_state->transition_.argument_;
 264     smx_simcall_t req = &pair->graph_state->executed_req_;
 265     if (req && req->call_ != SIMCALL_NONE)
 266       trace.push_back(simgrid::mc::request_to_string(
 267         req, req_num, simgrid::mc::RequestType::executed));
 268   }
 269   return trace;
 270 }
 271
 272 std::shared_ptr<Pair> LivenessChecker::create_pair(Pair* current_pair, xbt_automaton_state_t state,
 273                                                    std::shared_ptr<const std::vector<int>> propositions)
 274 {
 275   expanded_pairs_count_++;
 276   std::shared_ptr<Pair> next_pair = std::make_shared<Pair>(expanded_pairs_count_);
 277   next_pair->automaton_state      = state;
 278   next_pair->graph_state = std::shared_ptr<simgrid::mc::State>(new simgrid::mc::State(++expanded_states_count_));
 279   next_pair->atomic_propositions  = std::move(propositions);
 280   if (current_pair)
 281     next_pair->depth = current_pair->depth + 1;
 282   else
 283     next_pair->depth = 1;
 284   /* Get enabled actors and insert them in the interleave set of the next graph_state */
 285   for (auto& actor : mc_model_checker->process().actors())
 286     if (simgrid::mc::actor_is_enabled(actor.copy.get_buffer()))
 287       next_pair->graph_state->add_interleaving_set(actor.copy.get_buffer());
 288   next_pair->requests = next_pair->graph_state->interleave_size();
 289   /* FIXME : get search_cycle value for each accepting state */
 290   if (next_pair->automaton_state->type == 1 || (current_pair && current_pair->search_cycle))
 291     next_pair->search_cycle = true;
 292   else
 293     next_pair->search_cycle = false;
 294   return next_pair;
 295 }
 296
 297 void LivenessChecker::backtrack()
 298 {
 299   /* Traverse the stack backwards until a pair with a non empty interleave
 300      set is found, deleting all the pairs that have it empty in the way. */
 301   while (not exploration_stack_.empty()) {
 302     std::shared_ptr<simgrid::mc::Pair> current_pair = exploration_stack_.back();
 303     exploration_stack_.pop_back();
 304     if (current_pair->requests > 0) {
 305       /* We found a backtracking point */
 306       XBT_DEBUG("Backtracking to depth %d", current_pair->depth);
 307       exploration_stack_.push_back(std::move(current_pair));
 308       this->replay();
 309       XBT_DEBUG("Backtracking done");
 310       break;
 311     } else {
 312       XBT_DEBUG("Delete pair %d at depth %d", current_pair->num, current_pair->depth);
 313       if (current_pair->automaton_state->type == 1)
 314         this->remove_acceptance_pair(current_pair->num);
 315     }
 316   }
 317 }
 318
 319 void LivenessChecker::run()
 320 {
 321   XBT_INFO("Check the liveness property %s", _sg_mc_property_file.get().c_str());
 322   MC_automaton_load(_sg_mc_property_file.get().c_str());
 323
 324   XBT_DEBUG("Starting the liveness algorithm");
 325   simgrid::mc::session->initialize();
 326
 327   /* Initialize */
 328   this->previous_pair_ = 0;
 329
 330   std::shared_ptr<const std::vector<int>> propos = this->get_proposition_values();
 331
 332   // For each initial state of the property automaton, push a
 333   // (application_state, automaton_state) pair to the exploration stack:
 334   unsigned int cursor = 0;
 335   xbt_automaton_state_t automaton_state;
 336   xbt_dynar_foreach (simgrid::mc::property_automaton->states, cursor, automaton_state)
 337     if (automaton_state->type == -1)
 338       exploration_stack_.push_back(this->create_pair(nullptr, automaton_state, propos));
 339
 340   /* Actually run the double DFS search for counter-examples */
 341   while (not exploration_stack_.empty()) {
 342     std::shared_ptr<Pair> current_pair = exploration_stack_.back();
 343
 344     /* Update current state in buchi automaton */
 345     simgrid::mc::property_automaton->current_state = current_pair->automaton_state;
 346
 347     XBT_DEBUG(
 348         "********************* ( Depth = %d, search_cycle = %d, interleave size = %zu, pair_num = %d, requests = %d)",
 349         current_pair->depth, current_pair->search_cycle, current_pair->graph_state->interleave_size(),
 350         current_pair->num, current_pair->requests);
 351
 352     if (current_pair->requests == 0) {
 353       this->backtrack();
 354       continue;
 355     }
 356
 357     std::shared_ptr<VisitedPair> reached_pair;
 358     if (current_pair->automaton_state->type == 1 && not current_pair->exploration_started) {
 359       reached_pair = this->insert_acceptance_pair(current_pair.get());
 360       if (reached_pair == nullptr) {
 361         this->show_acceptance_cycle(current_pair->depth);
 362         throw simgrid::mc::LivenessError();
 363       }
 364     }
 365
 366     /* Pair already visited ? stop the exploration on the current path */
 367     if (not current_pair->exploration_started) {
 368       int visited_num = this->insert_visited_pair(reached_pair, current_pair.get());
 369       if (visited_num != -1) {
 370         if (dot_output != nullptr) {
 371           fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", this->previous_pair_, visited_num,
 372                   this->previous_request_.c_str());
 373           fflush(dot_output);
 374         }
 375         XBT_DEBUG("Pair already visited (equal to pair %d), exploration on the current path stopped.", visited_num);
 376         current_pair->requests = 0;
 377         this->backtrack();
 378         continue;
 379       }
 380     }
 381
 382     smx_simcall_t req = MC_state_choose_request(current_pair->graph_state.get());
 383     int req_num       = current_pair->graph_state->transition_.argument_;
 384
 385     if (dot_output != nullptr) {
 386       if (this->previous_pair_ != 0 && this->previous_pair_ != current_pair->num) {
 387         fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", this->previous_pair_, current_pair->num,
 388                 this->previous_request_.c_str());
 389         this->previous_request_.clear();
 390       }
 391       this->previous_pair_    = current_pair->num;
 392       this->previous_request_ = simgrid::mc::request_get_dot_output(req, req_num);
 393       if (current_pair->search_cycle)
 394         fprintf(dot_output, "%d [shape=doublecircle];\n", current_pair->num);
 395       fflush(dot_output);
 396     }
 397
 398     XBT_DEBUG("Execute: %s",
 399       simgrid::mc::request_to_string(
 400         req, req_num, simgrid::mc::RequestType::simix).c_str());
 401
 402     /* Update stats */
 403     mc_model_checker->executed_transitions++;
 404     if (not current_pair->exploration_started)
 405       visited_pairs_count_++;
 406
 407     /* Answer the request */
 408     mc_model_checker->handle_simcall(current_pair->graph_state->transition_);
 409
 410     /* Wait for requests (schedules processes) */
 411     mc_model_checker->wait_for_requests();
 412
 413     current_pair->requests--;
 414     current_pair->exploration_started = true;
 415
 416     /* Get values of atomic propositions (variables used in the property formula) */
 417     std::shared_ptr<const std::vector<int>> prop_values = this->get_proposition_values();
 418
 419     // For each enabled transition in the property automaton, push a
 420     // (application_state, automaton_state) pair to the exploration stack:
 421     for (int i = xbt_dynar_length(current_pair->automaton_state->out) - 1; i >= 0; i--) {
 422       xbt_automaton_transition_t transition_succ = (xbt_automaton_transition_t)xbt_dynar_get_as(
 423           current_pair->automaton_state->out, i, xbt_automaton_transition_t);
 424       if (evaluate_label(transition_succ->label, *prop_values))
 425         exploration_stack_.push_back(this->create_pair(current_pair.get(), transition_succ->dst, prop_values));
 426      }
 427
 428   }
 429
 430   XBT_INFO("No property violation found.");
 431   simgrid::mc::session->log_state();
 432 }
 433
 434 Checker* createLivenessChecker(Session& s)
 435 {
 436   return new LivenessChecker(s);
 437 }
 438
 439 }
 440 }