* 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/remote/mc_protocol.h"
#include "src/mc/transition/Transition.hpp"
-#include "src/xbt/mmalloc/mmprivate.h"
+#include "xbt/asserts.h"
#include "xbt/log.h"
#include "xbt/string.hpp"
#include "xbt/sysdep.h"
#include <cassert>
#include <cstdio>
+#include <algorithm>
#include <memory>
#include <string>
+#include <unordered_set>
#include <vector>
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_dfs, mc, "DFS exploration algorithm of the model-checker");
xbt::signal<void(RemoteApp&)> DFSExplorer::on_log_state_signal;
-void DFSExplorer::check_non_termination(const State* current_state)
-{
- for (auto const& state : stack_) {
- 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 ***");
- XBT_INFO("******************************************");
- XBT_INFO("Counter-example execution trace:");
- for (auto const& s : get_textual_trace())
- XBT_INFO(" %s", s.c_str());
- XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
- "--cfg=model-check/replay:'%s'",
- get_record_trace().to_string().c_str());
- log_state();
-
- throw TerminationError();
- }
- }
-}
-
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<std::string> DFSExplorer::get_textual_trace() // override
+void DFSExplorer::restore_stack(std::shared_ptr<State> state)
{
- std::vector<std::string> 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();
+ execution_seq_ = odpor::Execution();
+ 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 || reduction_mode_ == ReductionMode::odpor) {
+ // NOTE: The outgoing transition for the top-most state of the stack refers to that which was taken
+ // as part of the last trace explored by the algorithm. Thus, only the sequence of transitions leading up to,
+ // but not including, the last state must be included when reconstructing the Exploration for SDPOR.
+ for (auto iter = std::next(stack_.begin()); iter != stack_.end(); ++iter) {
+ execution_seq_.push_transition((*iter)->get_transition_in());
+ }
+ XBT_DEBUG("Replaced SDPOR/ODPOR execution to reflect the new stack");
}
- return trace;
}
void DFSExplorer::log_state() // override
on_log_state_signal(get_remote_app());
XBT_INFO("DFS exploration ended. %ld unique states visited; %lu backtracks (%lu transition replays, %lu states "
"visited overall)",
- State::get_expanded_states(), backtrack_count_, visited_states_count_,
- Transition::get_replayed_transitions());
+ State::get_expanded_states(), backtrack_count_, Transition::get_replayed_transitions(),
+ visited_states_count_);
Exploration::log_state();
}
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(),
XBT_ERROR("/!\\ Max depth of %d reached! THIS WILL PROBABLY BREAK the dpor reduction /!\\",
_sg_mc_max_depth.get());
XBT_ERROR("/!\\ If bad things happen, disable dpor with --cfg=model-check/reduction:none /!\\");
- } else
+ } else if (reduction_mode_ == ReductionMode::sdpor || reduction_mode_ == ReductionMode::odpor) {
+ XBT_ERROR("/!\\ Max depth of %d reached! THIS **WILL** BREAK the reduction, which is not sound "
+ "when stopping at a fixed depth /!\\",
+ _sg_mc_max_depth.get());
+ XBT_ERROR("/!\\ If bad things happen, disable the reduction with --cfg=model-check/reduction:none /!\\");
+ } else {
XBT_WARN("/!\\ Max depth reached ! /!\\ ");
+ }
this->backtrack();
continue;
}
- // 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_);
-
- visited_state_ = nullptr;
- this->backtrack();
- continue;
+ if (reduction_mode_ == ReductionMode::odpor) {
+ // In the case of ODPOR, the wakeup tree for this state may be empty if we're exploring new territory
+ // (rather than following the partial execution of a wakeup tree). This corresponds to lines 9 to 13 of
+ // the ODPOR pseudocode
+ //
+ // INVARIANT: The execution sequence should be consistent with the state when seeding the tree. If the sequence
+ // gets out of sync with the state, selection will not work as we intend
+ state->seed_wakeup_tree_if_needed(execution_seq_);
}
// Search for the 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);
+ // next_transition returns a pair<aid_t, int>
+ // in case we want to consider multiple states (eg. during backtrack)
+ const aid_t next = reduction_mode_ == ReductionMode::odpor ? state->next_odpor_transition()
+ : std::get<0>(state->next_transition_guided());
+
+ if (next < 0 || not state->is_actor_enabled(next)) {
+ if (next >= 0) { // Actor is not enabled, then
+ XBT_DEBUG(
+ "Reduction %s wants to execute a disabled transition %s. If it's ODPOR, ReversibleRace is suboptimal.",
+ to_c_str(reduction_mode_), state->get_actors_list().at(next).get_transition()->to_string(true).c_str());
+ if (reduction_mode_ == ReductionMode::odpor) {
+ // Remove the disabled transition from the wakeup tree so that ODPOR doesn't try it again
+ state->remove_subtree_at_aid(next);
+ state->add_sleep_set(state->get_actors_list().at(next).get_transition());
+ } else {
+ xbt_assert(false, "Only ODPOR should be confident enought in itself to try executing a disabled transition");
+ }
+ }
+ // If there is no more transition in the current state (or if ODPOR picked an actor that is not enabled --
+ // ReversibleRace is an overapproximation), backtrace
+ 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();
continue;
}
- if (_sg_mc_sleep_set && XBT_LOG_ISENABLED(mc_dfs, xbt_log_priority_verbose)) {
+ if (XBT_LOG_ISENABLED(mc_dfs, xbt_log_priority_verbose)) {
XBT_VERB("Sleep set actually containing:");
- for (auto& [aid, transition] : state->get_sleep_set())
- XBT_VERB(" <%ld,%s>", aid, transition.to_string().c_str());
+ for (const auto& [aid, transition] : state->get_sleep_set())
+ XBT_VERB(" <%ld,%s>", aid, transition->to_string().c_str());
}
+ auto todo = state->get_actors_list().at(next).get_transition();
+ XBT_DEBUG("wanna execute %ld: %.60s", next, todo->to_string().c_str());
+
/* 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());
+ 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("Executed %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<State> next_state;
-
- next_state = std::make_unique<State>(get_remote_app(), state);
+ auto next_state = std::make_shared<State>(get_remote_app(), state);
on_state_creation_signal(next_state.get(), 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
-
+ if (reduction_mode_ == ReductionMode::odpor) {
+ // With ODPOR, after taking a step forward, we must assign a copy of that subtree to the next state.
+ //
+ // NOTE: We only add actions to the sleep set AFTER we've regenerated states. We must perform the search
+ // fully down a single path before we consider adding any elements to the sleep set according to the pseudocode
+ next_state->sprout_tree_from_parent_state();
+ } else {
+ /* 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_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 considered 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(" #%ld %s (state=%ld)", prev_state->get_transition_out()->aid_,
+ prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num());
+ XBT_VERB(" #%ld %s (state=%ld)", state->get_transition_out()->aid_,
+ 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(" #%ld %s (state=%ld)", prev_state->get_transition_out()->aid_,
+ prev_state->get_transition_out()->to_string().c_str(), prev_state->get_num());
+ XBT_VERB(" #%ld %s (state=%ld)", state->get_transition_out()->aid_,
+ 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 `E` 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` that doesn't depend on it (`v := notdep(r, E)`) and then `p` to
+ * flip the race.
+ *
+ * The intuition is that some subsequence of `v` may enable `p`, so we want to be sure that search "in that
+ * direction"
+ */
+ execution_seq_.push_transition(std::move(executed_transition));
+ xbt_assert(execution_seq_.get_latest_event_handle().has_value(), "No events are contained in the SDPOR execution "
+ "even though one was just added");
+
+ const auto next_E_p = execution_seq_.get_latest_event_handle().value();
+ for (const auto e_race : execution_seq_.get_reversible_races_of(next_E_p)) {
+ State* prev_state = stack_[e_race].get();
+ const auto choices = execution_seq_.get_missing_source_set_actors_from(e_race, prev_state->get_backtrack_set());
+ if (not choices.empty()) {
+ // 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 best
+ //
+ // Here, we choose the actor with the lowest ID to ensure we get deterministic results
+ const auto q =
+ std::min_element(choices.begin(), choices.end(), [](const aid_t a1, const aid_t a2) { return a1 < a2; });
+ prev_state->consider_one(*q);
+ opened_states_.emplace_back(std::move(prev_state));
}
}
+ } else if (reduction_mode_ == ReductionMode::odpor) {
+ // In the case of ODPOR, we simply observe the transition that was executed until we've reached a maximal trace
+ execution_seq_.push_transition(std::move(executed_transition));
}
- if (_sg_mc_termination)
- this->check_non_termination(next_state.get());
+ // 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());
- /* 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());
+ 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();
-
- 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(),
- 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));
- }
+ /* Get an enabled process and insert it in the interleave set of the next state */
+ 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();
+ }
+ dot_output("\"%ld\" -> \"%ld\" [%s];\n", state->get_num(), stack_.back()->get_num(),
+ state->get_transition_out()->dot_string().c_str());
+ }
log_state();
}
+std::shared_ptr<State> 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;
+ }
+
+ std::shared_ptr<State> 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_));
+
+ return best_state;
+}
+
+std::shared_ptr<State> DFSExplorer::next_odpor_state()
+{
+ for (auto iter = stack_.rbegin(); iter != stack_.rend(); ++iter) {
+ const auto& state = *iter;
+ state->do_odpor_unwind();
+ XBT_DEBUG("\tPerformed ODPOR 'clean-up'. Sleep set has:");
+ for (const auto& [aid, transition] : state->get_sleep_set())
+ XBT_DEBUG("\t <%ld,%s>", aid, transition->to_string().c_str());
+ if (not state->has_empty_tree()) {
+ return state;
+ }
+ }
+ return nullptr;
+}
+
void DFSExplorer::backtrack()
{
- backtrack_count_++;
+ if (const auto last_event = execution_seq_.get_latest_event_handle();
+ reduction_mode_ == ReductionMode::odpor and last_event.has_value()) {
+ /**
+ * ODPOR Race Detection Procedure:
+ *
+ * For each reversible race in the current execution, we note if there are any continuations `C` equivalent to that
+ * which would reverse the race that have already either a) been searched by ODPOR or b) been *noted* to be searched
+ * by the wakeup tree at the appropriate reversal point, either as `C` directly or an as equivalent to `C`
+ * ("eventually looks like C", viz. the `~_E` relation)
+ */
+ for (auto e_prime = static_cast<odpor::Execution::EventHandle>(0); e_prime <= last_event.value(); ++e_prime) {
+ XBT_DEBUG("ODPOR: Now considering all possible race with `%u`", e_prime);
+ for (const auto e : execution_seq_.get_reversible_races_of(e_prime)) {
+ XBT_DEBUG("ODPOR: Reversible race detected between events `%u` and `%u`", e, e_prime);
+ State& prev_state = *stack_[e];
+ if (const auto v = execution_seq_.get_odpor_extension_from(e, e_prime, prev_state); v.has_value()) {
+ switch (prev_state.insert_into_wakeup_tree(v.value(), execution_seq_.get_prefix_before(e))) {
+ case odpor::WakeupTree::InsertionResult::root: {
+ XBT_DEBUG("ODPOR: Reversible race with `%u`(%ld: %.20s) unaccounted for in the wakeup tree for "
+ "the execution prior to event `%u`(%ld: %.20s):",
+ e_prime, stack_[e_prime]->get_transition_out()->aid_,
+ stack_[e_prime]->get_transition_out()->to_string(true).c_str(), e,
+ prev_state.get_transition_out()->aid_,
+ prev_state.get_transition_out()->to_string(true).c_str());
+ break;
+ }
+ case odpor::WakeupTree::InsertionResult::interior_node: {
+ XBT_DEBUG("ODPOR: Reversible race with `%u` partially accounted for in the wakeup tree for "
+ "the execution prior to event `%u`:",
+ e_prime, e);
+ break;
+ }
+ case odpor::WakeupTree::InsertionResult::leaf: {
+ XBT_DEBUG("ODPOR: Reversible race with `%u` accounted for in the wakeup tree for "
+ "the execution prior to event `%u`:",
+ e_prime, e);
+ break;
+ }
+ }
+ for (const auto& seq : simgrid::mc::odpor::get_textual_trace(v.value())) {
+ XBT_DEBUG(" %s", seq.c_str());
+ }
+ } else {
+ XBT_DEBUG("ODPOR: Ignoring race: `sleep(E')` intersects `WI_[E'](v := notdep(%u, E))`", e);
+ XBT_DEBUG("Sleep set contains:");
+ for (const auto& [aid, transition] : prev_state.get_sleep_set())
+ XBT_DEBUG(" <%ld,%s>", aid, transition->to_string().c_str());
+ }
+ }
+ }
+ }
+
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> state = std::move(stack_.back());
-
- stack_.pop_back();
+ // Take the point with smallest distance
+ auto backtracking_point = reduction_mode_ == ReductionMode::odpor ? next_odpor_state() : best_opened_state();
+ // 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 (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);
+ // We found a backtracking point, let's go to it
+ backtrack_count_++;
+ XBT_DEBUG("Backtracking to state#%ld", backtracking_point->get_num());
- } 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;
- }
+ // Search how to restore the backtracking point
+ std::deque<Transition*> replay_recipe;
+ for (const auto* s = backtracking_point.get(); s != nullptr; s = s->get_parent_state().get()) {
+ if (s->get_transition_in() != nullptr) // The root has no transition_in
+ replay_recipe.push_front(s->get_transition_in().get());
}
- 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;
- }
+ // Restore the initial state if no intermediate state was found
+ 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(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<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
+DFSExplorer::DFSExplorer(const std::vector<char*>& args, ReductionMode mode) : Exploration(args), reduction_mode_(mode)
{
- if (with_dpor)
- reduction_mode_ = ReductionMode::dpor;
- else
- reduction_mode_ = ReductionMode::none;
-
- if (_sg_mc_termination) {
- if (with_dpor) {
- XBT_INFO("Check non progressive cycles (turning DPOR off)");
- reduction_mode_ = ReductionMode::none;
- } else {
- XBT_INFO("Check non progressive cycles");
- }
- } else
- XBT_INFO("Start a DFS exploration. Reduction is: %s.", to_c_str(reduction_mode_));
+ XBT_INFO("Start a DFS exploration. Reduction is: %s.", to_c_str(reduction_mode_));
- auto initial_state = std::make_unique<State>(get_remote_app());
+ auto initial_state = std::make_shared<State>(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<char*>& args, bool with_dpor)
+Exploration* create_dfs_exploration(const std::vector<char*>& args, ReductionMode mode)
{
- return new DFSExplorer(args, with_dpor);
+ return new DFSExplorer(args, mode);
}
} // namespace simgrid::mc
