X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/9d195a1f6e6006762e394ab69955d0824bbfe2d8..86a552c797938ffe6db296e12b7043c3c7fdf14f:/src/mc/explo/DFSExplorer.cpp diff --git a/src/mc/explo/DFSExplorer.cpp b/src/mc/explo/DFSExplorer.cpp index 5632d1fff3..3f44ee29bf 100644 --- a/src/mc/explo/DFSExplorer.cpp +++ b/src/mc/explo/DFSExplorer.cpp @@ -4,13 +4,16 @@ * under the terms of the license (GNU LGPL) which comes with this package. */ #include "src/mc/explo/DFSExplorer.hpp" -#include "src/mc/VisitedState.hpp" #include "src/mc/mc_config.hpp" #include "src/mc/mc_exit.hpp" #include "src/mc/mc_private.hpp" #include "src/mc/mc_record.hpp" #include "src/mc/transition/Transition.hpp" +#if SIMGRID_HAVE_STATEFUL_MC +#include "src/mc/VisitedState.hpp" +#endif + #include "src/xbt/mmalloc/mmprivate.h" #include "xbt/log.h" #include "xbt/string.hpp" @@ -19,8 +22,10 @@ #include #include +#include #include #include +#include #include XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_dfs, mc, "DFS exploration algorithm of the model-checker"); @@ -41,6 +46,7 @@ xbt::signal DFSExplorer::on_log_state_signal; void DFSExplorer::check_non_termination(const State* current_state) { +#if SIMGRID_HAVE_STATEFUL_MC for (auto const& state : stack_) { if (state->get_system_state()->equals_to(*current_state->get_system_state(), *get_remote_app().get_remote_process_memory())) { @@ -56,27 +62,45 @@ void DFSExplorer::check_non_termination(const State* current_state) get_record_trace().to_string().c_str()); log_state(); - throw TerminationError(); + throw McError(ExitStatus::NON_TERMINATION); } } +#endif } RecordTrace DFSExplorer::get_record_trace() // override { RecordTrace res; - for (auto const& state : stack_) - res.push_back(state->get_transition()); + + if (const auto trans = stack_.back()->get_transition_out(); trans != nullptr) + res.push_back(trans.get()); + for (const auto* state = stack_.back().get(); state != nullptr; state = state->get_parent_state().get()) + if (state->get_transition_in() != nullptr) + res.push_front(state->get_transition_in().get()); + return res; } -std::vector DFSExplorer::get_textual_trace() // override +void DFSExplorer::restore_stack(std::shared_ptr state) { - std::vector trace; - for (auto const& state : stack_) { - const auto* t = state->get_transition(); - trace.push_back(xbt::string_printf("%ld: %s", t->aid_, t->to_string().c_str())); + stack_.clear(); + auto current_state = state; + stack_.emplace_front(current_state); + // condition corresponds to reaching initial state + while (current_state->get_parent_state() != nullptr) { + current_state = current_state->get_parent_state(); + stack_.emplace_front(current_state); + } + XBT_DEBUG("Replaced stack by %s", get_record_trace().to_string().c_str()); + + if (reduction_mode_ == ReductionMode::sdpor) { + if (stack_.empty()) { + execution_seq_ = sdpor::Execution(); + } else { + execution_seq_ = execution_seq_.get_prefix_up_to(stack_.size() - 1); + } + XBT_DEBUG("Additionally replaced corresponding SDPOR execution stack"); } - return trace; } void DFSExplorer::log_state() // override @@ -98,7 +122,7 @@ void DFSExplorer::run() while (not stack_.empty()) { /* Get current state */ - State* state = stack_.back().get(); + auto state = stack_.back(); XBT_DEBUG("**************************************************"); XBT_DEBUG("Exploration depth=%zu (state:#%ld; %zu interleaves todo)", stack_.size(), state->get_num(), @@ -118,6 +142,7 @@ void DFSExplorer::run() continue; } +#if SIMGRID_HAVE_STATEFUL_MC // Backtrack if we are revisiting a state we saw previously while applying state-equality reduction if (visited_state_ != nullptr) { XBT_DEBUG("State already visited (equal to state %ld), exploration stopped on this path.", @@ -127,14 +152,15 @@ void DFSExplorer::run() this->backtrack(); continue; } +#endif // Search for the next transition - // next_transition returns a pair in case we want to consider multiple state + // next_transition returns a pair in case we want to consider multiple state (eg. during backtrack) auto [next, _] = state->next_transition_guided(); if (next < 0) { // If there is no more transition in the current state, backtrack. - XBT_DEBUG("There remains %lu actors, but none to interleave (depth %zu).", state->get_actor_count(), - stack_.size() + 1); + XBT_VERB("%lu actors remain, but none of them need to be interleaved (depth %zu).", state->get_actor_count(), + stack_.size() + 1); if (state->get_actor_count() == 0) { get_remote_app().finalize_app(); @@ -153,18 +179,16 @@ void DFSExplorer::run() } /* Actually answer the request: let's execute the selected request (MCed does one step) */ - state->execute_next(next, get_remote_app()); - on_transition_execute_signal(state->get_transition(), get_remote_app()); + const auto executed_transition = state->execute_next(next, get_remote_app()); + on_transition_execute_signal(state->get_transition_out().get(), get_remote_app()); // If there are processes to interleave and the maximum depth has not been // reached then perform one step of the exploration algorithm. - XBT_VERB("Execute %ld: %.60s (stack depth: %zu, state: %ld, %zu interleaves)", state->get_transition()->aid_, - state->get_transition()->to_string().c_str(), stack_.size(), state->get_num(), state->count_todo()); + XBT_VERB("Execute %ld: %.60s (stack depth: %zu, state: %ld, %zu interleaves)", state->get_transition_out()->aid_, + state->get_transition_out()->to_string().c_str(), stack_.size(), state->get_num(), state->count_todo()); /* Create the new expanded state (copy the state of MCed into our MCer data) */ - std::unique_ptr next_state; - - next_state = std::make_unique(get_remote_app(), state); + auto next_state = std::make_shared(get_remote_app(), state); on_state_creation_signal(next_state.get(), get_remote_app()); /* Sleep set procedure: @@ -172,132 +196,244 @@ void DFSExplorer::run() * Since the parent sleep set is used to compute the child sleep set, this need to be * done after next_state creation */ XBT_DEBUG("Marking Transition >>%s<< of process %ld done and adding it to the sleep set", - state->get_transition()->to_string().c_str(), state->get_transition()->aid_); - state->add_sleep_set(state->get_transition()); // Actors are marked done when they are considerd in ActorState - + state->get_transition_out()->to_string().c_str(), state->get_transition_out()->aid_); + state->add_sleep_set(state->get_transition_out()); // Actors are marked done when they are considerd in ActorState + /* DPOR persistent set procedure: * for each new transition considered, check if it depends on any other previous transition executed before it * on another process. If there exists one, find the more recent, and add its process to the interleave set. * If the process is not enabled at this point, then add every enabled process to the interleave */ if (reduction_mode_ == ReductionMode::dpor) { - aid_t issuer_id = state->get_transition()->aid_; - for (auto i = stack_.rbegin(); i != stack_.rend(); ++i) { - State* prev_state = i->get(); - if (state->get_transition()->aid_ == prev_state->get_transition()->aid_) { - XBT_DEBUG("Simcall >>%s<< and >>%s<< with same issuer %ld", state->get_transition()->to_string().c_str(), - prev_state->get_transition()->to_string().c_str(), issuer_id); + aid_t issuer_id = state->get_transition_out()->aid_; + stack_t tmp_stack = stack_; + while (not tmp_stack.empty()) { + if (const State* prev_state = tmp_stack.back().get(); + state->get_transition_out()->aid_ == prev_state->get_transition_out()->aid_) { + XBT_DEBUG("Simcall >>%s<< and >>%s<< with same issuer %ld", state->get_transition_out()->to_string().c_str(), + prev_state->get_transition_out()->to_string().c_str(), issuer_id); + tmp_stack.pop_back(); continue; - } else if (prev_state->get_transition()->depends(state->get_transition())) { + } else if (prev_state->get_transition_out()->depends(state->get_transition_out().get())) { XBT_VERB("Dependent Transitions:"); - XBT_VERB(" %s (state=%ld)", prev_state->get_transition()->to_string().c_str(), prev_state->get_num()); - XBT_VERB(" %s (state=%ld)", state->get_transition()->to_string().c_str(), state->get_num()); + XBT_VERB(" %s (state=%ld)", prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num()); + XBT_VERB(" %s (state=%ld)", state->get_transition_out()->to_string().c_str(), state->get_num()); if (prev_state->is_actor_enabled(issuer_id)) { - if (not prev_state->is_actor_done(issuer_id)) + if (not prev_state->is_actor_done(issuer_id)) { prev_state->consider_one(issuer_id); - else + opened_states_.emplace_back(tmp_stack.back()); + } else XBT_DEBUG("Actor %ld is already in done set: no need to explore it again", issuer_id); } else { XBT_DEBUG("Actor %ld is not enabled: DPOR may be failing. To stay sound, we are marking every enabled " "transition as todo", issuer_id); - prev_state->consider_all(); + // If we ended up marking at least a transition, explore it at some point + if (prev_state->consider_all() > 0) + opened_states_.emplace_back(tmp_stack.back()); } break; } else { XBT_VERB("INDEPENDENT Transitions:"); - XBT_VERB(" %s (state=%ld)", prev_state->get_transition()->to_string().c_str(), prev_state->get_num()); - XBT_VERB(" %s (state=%ld)", state->get_transition()->to_string().c_str(), state->get_num()); + XBT_VERB(" %s (state=%ld)", prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num()); + XBT_VERB(" %s (state=%ld)", state->get_transition_out()->to_string().c_str(), state->get_num()); + } + tmp_stack.pop_back(); + } + } else if (reduction_mode_ == ReductionMode::sdpor) { + /** + * SDPOR Source Set Procedure: + * + * Find "reversible races" in the current execution with respect + * to the latest action `p`. For each such race, determine one thread + * not contained in the backtrack set at the "race point" `r` which + * "represents" the trace formed by first executing everything after + * `r` and then `p` to flip the race + */ + execution_seq_.push_transition(executed_transition.get()); + + xbt_assert(execution_seq_.get_latest_event_handle().has_value(), + "No events are contained in the SDPOR/OPDPOR execution " + "even though one was just added"); + const aid_t p = executed_transition->aid_; + const auto next_E_p = execution_seq_.get_latest_event_handle().value(); + + for (const auto racing_event_handle : execution_seq_.get_racing_events_of(next_E_p)) { + // To determine if the race is reversible, we have to ensure + // that actor `p` running `next_E_p` (viz. the event such that + // `racing_event -> (E_p) next_E_p` and no other event + // "happens-between" the two) is enabled in any equivalent + // execution where `racing_event` happens before `next_E_p`. + // + // Importantly, it is equivalent to checking if in ANY + // such equivalent execution sequence where `racing_event` + // happens-before `next_E_p` that `p` is enabled in `pre(racing_event, E.p)`. + // Thus it suffices to check THIS execution + // + // If the actor `p` is not enabled at s_[E'], it is not a *reversible* race + const std::shared_ptr prev_state = stack_[racing_event_handle]; + if (prev_state->is_actor_enabled(p)) { + // NOTE: To incorporate the idea of attempting to select the "best" + // backtrack point into SDPOR, instead of selecting the `first` initial, + // we should instead compute all choices and decide which is bes + const std::optional q = + execution_seq_.get_first_ssdpor_initial_from(racing_event_handle, prev_state->get_backtrack_set()); + if (q.has_value()) { + prev_state->consider_one(q.value()); + opened_states_.emplace_back(std::move(prev_state)); + } } } } + // Before leaving that state, if the transition we just took can be taken multiple times, we + // need to give it to the opened states + if (stack_.back()->count_todo_multiples() > 0) + opened_states_.emplace_back(stack_.back()); + if (_sg_mc_termination) this->check_non_termination(next_state.get()); - /* Check whether we already explored next_state in the past (but only if interested in state-equality reduction) */ +#if SIMGRID_HAVE_STATEFUL_MC + /* Check whether we already explored next_state in the past (but only if interested in state-equality reduction) + */ if (_sg_mc_max_visited_states > 0) visited_state_ = visited_states_.addVisitedState(next_state->get_num(), next_state.get(), get_remote_app()); +#endif + + stack_.emplace_back(std::move(next_state)); /* If this is a new state (or if we don't care about state-equality reduction) */ if (visited_state_ == nullptr) { /* Get an enabled process and insert it in the interleave set of the next state */ if (reduction_mode_ == ReductionMode::dpor) - next_state->consider_best(); // Take only one transition if DPOR: others may be considered later if required - else - next_state->consider_all(); + stack_.back()->consider_best(); // Take only one transition if DPOR: others may be considered later if required + else { + stack_.back()->consider_all(); + } - dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), next_state->get_num(), - state->get_transition()->dot_string().c_str()); - } else + dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(), + state->get_transition_out()->dot_string().c_str()); +#if SIMGRID_HAVE_STATEFUL_MC + } else { dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), visited_state_->original_num_ == -1 ? visited_state_->num_ : visited_state_->original_num_, - state->get_transition()->dot_string().c_str()); + state->get_transition_out()->dot_string().c_str()); +#endif + } + } + log_state(); +} + +std::shared_ptr DFSExplorer::best_opened_state() +{ + int best_prio = 0; // cache the value for the best priority found so far (initialized to silence gcc) + auto best = end(opened_states_); // iterator to the state to explore having the best priority + auto valid = begin(opened_states_); // iterator marking the limit between states still to explore, and already + // explored ones + + // Keep only still non-explored states (aid != -1), and record the one with the best (greater) priority. + for (auto current = begin(opened_states_); current != end(opened_states_); ++current) { + auto [aid, prio] = (*current)->next_transition_guided(); + if (aid == -1) + continue; + if (valid != current) + *valid = std::move(*current); + if (best == end(opened_states_) || prio > best_prio) { + best_prio = prio; + best = valid; + } + ++valid; + } - stack_.push_back(std::move(next_state)); + std::shared_ptr best_state; + if (best < valid) { + // There are non-explored states, and one of them has the best priority. Remove it from opened_states_ before + // returning. + best_state = std::move(*best); + --valid; + if (best != valid) + *best = std::move(*valid); } + opened_states_.erase(valid, end(opened_states_)); - log_state(); + return best_state; } void DFSExplorer::backtrack() { - backtrack_count_++; XBT_VERB("Backtracking from %s", get_record_trace().to_string().c_str()); + XBT_DEBUG("%lu alternatives are yet to be explored:", opened_states_.size()); + on_backtracking_signal(get_remote_app()); get_remote_app().check_deadlock(); - /* We may backtrack from somewhere either because it's leaf, or because every enabled process are in done/sleep set. - * In the first case, we need to remove the last transition corresponding to the Finalize */ - if (stack_.back()->get_transition()->aid_ == 0) - stack_.pop_back(); - - /* Traverse the stack backwards until a state with a non empty interleave set is found, deleting all the states that - * have it empty in the way. */ - bool found_backtracking_point = false; - while (not stack_.empty() && not found_backtracking_point) { - std::unique_ptr state = std::move(stack_.back()); - - stack_.pop_back(); + // Take the point with smallest distance + auto backtracking_point = best_opened_state(); - - if (state->count_todo() == 0) { // Empty interleaving set: exploration at this level is over - XBT_DEBUG("Delete state %ld at depth %zu", state->get_num(), stack_.size() + 1); - - } else { - XBT_DEBUG("Back-tracking to state %ld at depth %zu: %lu transitions left to be explored", state->get_num(), - stack_.size() + 1, state->count_todo()); - stack_.push_back( - std::move(state)); // Put it back on the stack so we can explore the next transition of the interleave - found_backtracking_point = true; - } + // if no backtracking point, then set the stack_ to empty so we can end the exploration + if (not backtracking_point) { + XBT_DEBUG("No more opened point of exploration, the search will end"); + stack_.clear(); + return; } - if (found_backtracking_point) { - /* If asked to rollback on a state that has a snapshot, restore it */ - State* last_state = stack_.back().get(); - if (const auto* system_state = last_state->get_system_state()) { - system_state->restore(*get_remote_app().get_remote_process_memory()); - on_restore_system_state_signal(last_state, get_remote_app()); - return; + // We found a backtracking point, let's go to it + backtrack_count_++; + XBT_DEBUG("Backtracking to state#%ld", backtracking_point->get_num()); + +#if SIMGRID_HAVE_STATEFUL_MC + /* If asked to rollback on a state that has a snapshot, restore it */ + if (const auto* system_state = backtracking_point->get_system_state()) { + system_state->restore(*get_remote_app().get_remote_process_memory()); + on_restore_system_state_signal(backtracking_point.get(), get_remote_app()); + this->restore_stack(backtracking_point); + return; + } +#endif + + // Search how to restore the backtracking point + State* init_state = nullptr; + std::deque replay_recipe; + for (auto* s = backtracking_point.get(); s != nullptr; s = s->get_parent_state().get()) { +#if SIMGRID_HAVE_STATEFUL_MC + if (s->get_system_state() != nullptr) { // Found a state that I can restore + init_state = s; + break; } +#endif + if (s->get_transition_in() != nullptr) // The root has no transition_in + replay_recipe.push_front(s->get_transition_in().get()); + } - /* if no snapshot, we need to restore the initial state and replay the transitions */ + // Restore the init_state, if any + if (init_state != nullptr) { +#if SIMGRID_HAVE_STATEFUL_MC + const auto* system_state = init_state->get_system_state(); + system_state->restore(*get_remote_app().get_remote_process_memory()); + on_restore_system_state_signal(init_state, get_remote_app()); +#endif + } else { // Restore the initial state if no intermediate state was found get_remote_app().restore_initial_state(); on_restore_initial_state_signal(get_remote_app()); + } - /* Traverse the stack from the state at position start and re-execute the transitions */ - for (std::unique_ptr const& state : stack_) { - if (state == stack_.back()) /* If we are arrived on the target state, don't replay the outgoing transition */ - break; - state->get_transition()->replay(get_remote_app()); - on_transition_replay_signal(state->get_transition(), get_remote_app()); - visited_states_count_++; - } - } // If no backtracing point, then the stack is empty and the exploration is over + /* if no snapshot, we need to restore the initial state and replay the transitions */ + /* Traverse the stack from the state at position start and re-execute the transitions */ + for (auto& transition : replay_recipe) { + transition->replay(get_remote_app()); + on_transition_replay_signal(transition, get_remote_app()); + visited_states_count_++; + } + this->restore_stack(backtracking_point); } -DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor) : Exploration(args, _sg_mc_termination) +DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor, bool need_memory_info) + : Exploration(args, need_memory_info || _sg_mc_termination +#if SIMGRID_HAVE_STATEFUL_MC + || _sg_mc_checkpoint > 0 +#endif + ) { if (with_dpor) reduction_mode_ = ReductionMode::dpor; @@ -314,18 +450,21 @@ DFSExplorer::DFSExplorer(const std::vector& args, bool with_dpor) : Explo } else XBT_INFO("Start a DFS exploration. Reduction is: %s.", to_c_str(reduction_mode_)); - auto initial_state = std::make_unique(get_remote_app()); + auto initial_state = std::make_shared(get_remote_app()); XBT_DEBUG("**************************************************"); + stack_.emplace_back(std::move(initial_state)); + /* Get an enabled actor and insert it in the interleave set of the initial state */ - XBT_DEBUG("Initial state. %lu actors to consider", initial_state->get_actor_count()); + XBT_DEBUG("Initial state. %lu actors to consider", stack_.back()->get_actor_count()); if (reduction_mode_ == ReductionMode::dpor) - initial_state->consider_best(); - else - initial_state->consider_all(); - - stack_.push_back(std::move(initial_state)); + stack_.back()->consider_best(); + else { + stack_.back()->consider_all(); + } + if (stack_.back()->count_todo_multiples() > 1) + opened_states_.emplace_back(stack_.back()); } Exploration* create_dfs_exploration(const std::vector& args, bool with_dpor)