void DFSExplorer::check_non_termination(const State* current_state)
{
for (auto const& state : stack_) {
- if (*state->get_system_state() == *current_state->get_system_state()) {
+ if (state->get_system_state()->equals_to(*current_state->get_system_state(),
+ *get_remote_app().get_remote_process_memory())) {
XBT_INFO("Non-progressive cycle: state %ld -> state %ld", state->get_num(), current_state->get_num());
XBT_INFO("******************************************");
XBT_INFO("*** NON-PROGRESSIVE CYCLE DETECTED ***");
continue;
}
- // Backtrack if we are revisiting a state we saw previously
+ // 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.",
visited_state_->original_num_ == -1 ? visited_state_->num_ : visited_state_->original_num_);
}
// Search for the next transition
- aid_t next = state->next_transition();
+ // next_transition returns a pair<aid_t, double> in case we want to consider multiple state
+ 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("There remains %lu actors, but none to interleave (depth %zu).", state->get_actor_count(),
+ stack_.size() + 1);
+
if (state->get_actor_count() == 0) {
- mc_model_checker->finalize_app();
+ get_remote_app().finalize_app();
XBT_VERB("Execution came to an end at %s (state: %ld, depth: %zu)", get_record_trace().to_string().c_str(),
state->get_num(), stack_.size());
-
}
-
+
this->backtrack();
continue;
}
}
/* Actually answer the request: let's execute the selected request (MCed does one step) */
- state->execute_next(next);
+ state->execute_next(next, get_remote_app());
on_transition_execute_signal(state->get_transition(), get_remote_app());
// If there are processes to interleave and the maximum depth has not been
state->get_transition()->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<State> next_state;
+ std::shared_ptr<State> next_state;
+ next_state = std::make_shared<State>(get_remote_app(), state);
+ on_state_creation_signal(next_state.get(), get_remote_app());
- /* If we want sleep set reduction, pass the old state to the new state so it can
- * both copy the sleep set and eventually removes things from it locally */
- if (_sg_mc_sleep_set)
- next_state = std::make_unique<State>(get_remote_app(), state);
- else
- next_state = std::make_unique<State>(get_remote_app());
+ /* Sleep set procedure:
+ * adding the taken transition to the sleep set of the original state.
+ * <!> 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
- on_state_creation_signal(next_state.get(), get_remote_app());
+ /* 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_;
+ stack_t tmp_stack = std::list(stack_);
+ while (not tmp_stack.empty()) {
+ State* prev_state = tmp_stack.back().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);
+ tmp_stack.pop_back();
+ continue;
+ } else if (prev_state->get_transition()->depends(state->get_transition())) {
+ 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());
+
+ if (prev_state->is_actor_enabled(issuer_id)) {
+ if (not prev_state->is_actor_done(issuer_id)) {
+ prev_state->consider_one(issuer_id);
+ opened_states.emplace_back(tmp_stack);
+ } 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();
+ opened_states.emplace_back(tmp_stack);
+ }
+ 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());
+ }
+ tmp_stack.pop_back();
+ }
+ }
-
if (_sg_mc_termination)
this->check_non_termination(next_state.get());
if (_sg_mc_max_visited_states > 0)
visited_state_ = visited_states_.addVisitedState(next_state->get_num(), next_state.get(), get_remote_app());
+ stack_.push_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 */
- for (auto const& [aid, _] : next_state->get_actors_list()) {
- if (next_state->is_actor_enabled(aid) and not next_state->is_actor_done(aid)) {
- next_state->mark_todo(aid);
- if (reduction_mode_ == ReductionMode::dpor)
- break; // With DPOR, we take the first enabled transition
- }
+ if (reduction_mode_ == ReductionMode::dpor)
+ stack_.back()->consider_best(); // Take only one transition if DPOR: others may be considered later if required
+ else {
+ stack_.back()->consider_all();
+ opened_states.emplace_back(stack_);
}
-
- dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), next_state->get_num(),
+ dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(),
state->get_transition()->dot_string().c_str());
} 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());
-
- stack_.push_back(std::move(next_state));
}
log_state();
on_backtracking_signal(get_remote_app());
get_remote_app().check_deadlock();
+ // if no backtracking point, then set the stack_ to empty so we can end the exploration
+ if (opened_states.size() == 0) {
+ stack_ = std::list<std::shared_ptr<State>>();
+ return;
+ }
+
/* 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. For each deleted state, check if the request that has generated it (from its
- * predecessor state) depends on any other previous request 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 */
- bool found_backtracking_point = false;
- while (not stack_.empty() && not found_backtracking_point) {
- std::unique_ptr<State> state = std::move(stack_.back());
-
stack_.pop_back();
- 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
-
- 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);
- continue;
- } else if (prev_state->get_transition()->depends(state->get_transition())) {
- 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());
-
- if (prev_state->is_actor_enabled(issuer_id)) {
- if (not prev_state->is_actor_done(issuer_id))
- prev_state->mark_todo(issuer_id);
- 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->mark_all_enabled_todo();
- }
- 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());
- }
- }
+ stack_t backtrack;
+ double min_dist = std::numeric_limits<double>::infinity();
+ aid_t min_aid = -1;
+ for (auto& stack : opened_states) {
+ auto [aid, dist] = stack.back()->next_transition_guided();
+ if (aid == -1)
+ continue;
+ if (dist < min_dist) {
+ min_dist = dist;
+ min_aid = aid;
+ backtrack = stack;
}
+ }
- 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);
+ if (min_aid == -1) {
+ stack_ = std::list<std::shared_ptr<State>>();
+ return;
+ }
- } 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 (backtrack.back()->count_todo() <= 1)
+ opened_states.pop_back();
+ XBT_VERB("%lu todo actors in last states of the next backtracking point %s (remaining %lu opened stacks)",
+ backtrack.back()->count_todo(), backtrack.back()->get_transition()->to_string().c_str(),
+ opened_states.size());
+
+ /* If asked to rollback on a state that has a snapshot, restore it */
+ State* last_state = backtrack.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;
}
- 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());
- on_restore_system_state_signal(last_state, get_remote_app());
- return;
- }
+ /* if no snapshot, we need to restore the initial state and replay the transitions */
+ get_remote_app().restore_initial_state();
+ on_restore_initial_state_signal(get_remote_app());
- /* if no snapshot, we need to restore the initial state and replay the transitions */
- 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<State> 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();
- 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
+ /* Traverse the stack from the state at position start and re-execute the transitions */
+ for (std::shared_ptr<State> const& state : backtrack) {
+ if (state == backtrack.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_++;
+ }
+ stack_ = backtrack;
+ XBT_VERB(">> Backtracked to %s", get_record_trace().to_string().c_str());
}
-DFSExplorer::DFSExplorer(const std::vector<char*>& args, bool with_dpor) : Exploration(args)
+// DFSExplorer::DFSExplorer(const std::vector<char*>& args, bool with_dpor) : Exploration(args, _sg_mc_termination) //
+// UNCOMMENT TO ACTIVATE REFORKS
+DFSExplorer::DFSExplorer(const std::vector<char*>& args, bool with_dpor)
+ : Exploration(args, true) // This version does not use reforks as it breaks
{
if (with_dpor)
reduction_mode_ = ReductionMode::dpor;
XBT_DEBUG("**************************************************");
+ stack_.push_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());
- for (auto const& [aid, _] : initial_state->get_actors_list()) {
- if (initial_state->is_actor_enabled(aid)) {
- initial_state->mark_todo(aid);
- if (reduction_mode_ == ReductionMode::dpor) {
- XBT_DEBUG("Actor %ld is TODO, DPOR is ON so let's go for this one.", aid);
- break;
- }
- XBT_DEBUG("Actor %ld is TODO", aid);
- }
+ if (reduction_mode_ == ReductionMode::dpor)
+ stack_.back()->consider_best();
+ else {
+ stack_.back()->consider_all();
+ opened_states.emplace_back(stack_);
}
-
- stack_.push_back(std::move(initial_state));
}
Exploration* create_dfs_exploration(const std::vector<char*>& args, bool with_dpor)