-/* Copyright (c) 2016-2022. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2016-2023. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
#include "src/mc/explo/UdporChecker.hpp"
+#include "src/mc/api/State.hpp"
+#include "src/mc/explo/udpor/maximal_subsets_iterator.hpp"
+#include <xbt/asserts.h>
#include <xbt/log.h>
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_udpor, mc, "Logging specific to MC safety verification ");
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_udpor, mc, "Logging specific to verification using UDPOR");
-namespace simgrid::mc {
+namespace simgrid::mc::udpor {
+
+UdporChecker::UdporChecker(const std::vector<char*>& args) : Exploration(args)
+{
+ // Initialize the map
+}
+
+void UdporChecker::run()
+{
+ XBT_INFO("Starting a UDPOR exploration");
+ // NOTE: `A`, `D`, and `C` are derived from the
+ // original UDPOR paper [1], while `prev_exC` arises
+ // from the incremental computation of ex(C) from [3]
+ Configuration C_root;
+
+ // TODO: Move computing the root configuration into a method on the Unfolding
+ auto initial_state = get_current_state();
+ auto root_event = std::make_unique<UnfoldingEvent>(EventSet(), std::make_shared<Transition>());
+ auto* root_event_handle = root_event.get();
+ unfolding.insert(std::move(root_event));
+ C_root.add_event(root_event_handle);
+
+ explore(C_root, EventSet(), EventSet(), std::move(initial_state), EventSet());
+
+ XBT_INFO("UDPOR exploration terminated -- model checking completed");
+}
+
+void UdporChecker::explore(const Configuration& C, EventSet D, EventSet A, std::unique_ptr<State> stateC,
+ EventSet prev_exC)
+{
+ auto exC = compute_exC(C, *stateC, prev_exC);
+ const auto enC = compute_enC(C, exC);
+
+ // If enC is a subset of D, intuitively
+ // there aren't any enabled transitions
+ // which are "worth" exploring since their
+ // exploration would lead to a so-called
+ // "sleep-set blocked" trace.
+ if (enC.is_subset_of(D)) {
+
+ if (not C.get_events().empty()) {
+ // Report information...
+ }
+
+ // When `en(C)` is empty, intuitively this means that there
+ // are no enabled transitions that can be executed from the
+ // state reached by `C` (denoted `state(C)`), i.e. by some
+ // execution of the transitions in C obeying the causality
+ // relation. Here, then, we would be in a deadlock.
+ if (enC.empty()) {
+ get_remote_app().check_deadlock();
+ }
+
+ return;
+ }
+
+ // TODO: Add verbose logging about which event is being explored
-UdporChecker::UdporChecker(RemoteApp& remote_app) : Exploration(remote_app) {}
+ const UnfoldingEvent* e = select_next_unfolding_event(A, enC);
+ xbt_assert(e != nullptr, "\n\n****** INVARIANT VIOLATION ******\n"
+ "UDPOR guarantees that an event will be chosen at each point in\n"
+ "the search, yet no events were actually chosen\n"
+ "*********************************\n\n");
+
+ // Move the application into stateCe and actually make note of that state
+ move_to_stateCe(*stateC, *e);
+ auto stateCe = record_current_state();
+
+ // Ce := C + {e}
+ Configuration Ce = C;
+ Ce.add_event(e);
+
+ A.remove(e);
+ exC.remove(e);
+
+ // Explore(C + {e}, D, A \ {e})
+ explore(Ce, D, std::move(A), std::move(stateCe), std::move(exC));
+
+ // D <-- D + {e}
+ D.insert(e);
+
+ // TODO: Determine a value of K to use or don't use it at all
+ constexpr unsigned K = 10;
+ if (auto J = compute_partial_alternative(D, C, K); !J.empty()) {
+ J.subtract(C.get_events());
+
+ // Before searching the "right half", we need to make
+ // sure the program actually reflects the fact
+ // that we are searching again from `stateC` (the recursive
+ // search moved the program into `stateCe`)
+ restore_program_state_to(*stateC);
+
+ // Explore(C, D + {e}, J \ C)
+ explore(C, D, std::move(J), std::move(stateC), std::move(prev_exC));
+ }
+
+ // D <-- D - {e}
+ D.remove(e);
+
+ // Remove(e, C, D)
+ clean_up_explore(e, C, D);
+}
+
+EventSet UdporChecker::compute_exC(const Configuration& C, const State& stateC, const EventSet& prev_exC)
+{
+ // See eqs. 5.7 of section 5.2 of [3]
+ // C = C' + {e_cur}, i.e. C' = C - {e_cur}
+ //
+ // Then
+ //
+ // ex(C) = ex(C' + {e_cur}) = ex(C') / {e_cur} +
+ // U{<a, K> : K is maximal, `a` depends on all of K, `a` enabled at config(K) }
+ const UnfoldingEvent* e_cur = C.get_latest_event();
+ EventSet exC = prev_exC;
+ exC.remove(e_cur);
+
+ for (const auto& [aid, actor_state] : stateC.get_actors_list()) {
+ for (const auto& transition : actor_state.get_enabled_transitions()) {
+ // First check for a specialized function that can compute the extension
+ // set "quickly" based on its type. Otherwise, fall back to computing
+ // the set "by hand"
+ const auto specialized_extension_function = incremental_extension_functions.find(transition->type_);
+ if (specialized_extension_function != incremental_extension_functions.end()) {
+ exC.form_union((specialized_extension_function->second)(C, transition));
+ } else {
+ exC.form_union(this->compute_exC_by_enumeration(C, transition));
+ }
+ }
+ }
+ return exC;
+}
+
+EventSet UdporChecker::compute_exC_by_enumeration(const Configuration& C, const std::shared_ptr<Transition> action)
+{
+ // Here we're computing the following:
+ //
+ // U{<a, K> : K is maximal, `a` depends on all of K, `a` enabled at config(K) }
+ //
+ // where `a` is the `action` given to us. Note that `a` is presumed to be enabled
+ EventSet incremental_exC;
-void UdporChecker::run() {}
+ for (auto begin =
+ maximal_subsets_iterator(C, {[&](const UnfoldingEvent* e) { return e->is_dependent_with(action.get()); }});
+ begin != maximal_subsets_iterator(); ++begin) {
+ const EventSet& maximal_subset = *begin;
+
+ // TODO: Determine if `a` is enabled here
+ const bool enabled_at_config_k = false;
+
+ if (enabled_at_config_k) {
+ auto candidate_handle = std::make_unique<UnfoldingEvent>(maximal_subset, action);
+ if (auto candidate_event = candidate_handle.get(); not unfolding.contains_event_equivalent_to(candidate_event)) {
+ // This is a new event (i.e. one we haven't yet seen)
+ unfolding.insert(std::move(candidate_handle));
+ incremental_exC.insert(candidate_event);
+ }
+ }
+ }
+
+ return incremental_exC;
+}
+
+EventSet UdporChecker::compute_enC(const Configuration& C, const EventSet& exC) const
+{
+ EventSet enC;
+ for (const auto e : exC) {
+ if (not e->conflicts_with(C)) {
+ enC.insert(e);
+ }
+ }
+ return enC;
+}
+
+void UdporChecker::move_to_stateCe(State& state, const UnfoldingEvent& e)
+{
+ const aid_t next_actor = e.get_transition()->aid_;
+
+ // TODO: Add the trace if possible for reporting a bug
+ xbt_assert(next_actor >= 0, "\n\n****** INVARIANT VIOLATION ******\n"
+ "In reaching this execution path, UDPOR ensures that at least one\n"
+ "one transition of the state of an visited event is enabled, yet no\n"
+ "state was actually enabled. Please report this as a bug.\n"
+ "*********************************\n\n");
+ state.execute_next(next_actor, get_remote_app());
+}
+
+void UdporChecker::restore_program_state_to(const State& stateC)
+{
+ // TODO: Perform state regeneration in the same manner as is done
+ // in the DFSChecker.cpp
+}
+
+std::unique_ptr<State> UdporChecker::record_current_state()
+{
+ auto next_state = this->get_current_state();
+
+ // In UDPOR, we care about all enabled transitions in a given state
+ next_state->mark_all_enabled_todo();
+
+ return next_state;
+}
+
+const UnfoldingEvent* UdporChecker::select_next_unfolding_event(const EventSet& A, const EventSet& enC)
+{
+ if (!enC.empty()) {
+ return *(enC.begin());
+ }
+
+ for (const auto& event : A) {
+ if (enC.contains(event)) {
+ return event;
+ }
+ }
+ return nullptr;
+}
+
+EventSet UdporChecker::compute_partial_alternative(const EventSet& D, const Configuration& C, const unsigned k) const
+{
+ // TODO: Compute k-partial alternatives using [2]
+ return EventSet();
+}
+
+void UdporChecker::clean_up_explore(const UnfoldingEvent* e, const Configuration& C, const EventSet& D)
+{
+ // TODO: Perform clean up here
+}
RecordTrace UdporChecker::get_record_trace()
{
std::vector<std::string> UdporChecker::get_textual_trace()
{
+ // TODO: Topologically sort the events of the latest configuration
+ // and iterate through that topological sorting
std::vector<std::string> trace;
return trace;
}
-void UdporChecker::log_state()
-{
- Exploration::log_state();
-}
+} // namespace simgrid::mc::udpor
+
+namespace simgrid::mc {
-Exploration* create_udpor_checker(RemoteApp& remote_app)
+Exploration* create_udpor_checker(const std::vector<char*>& args)
{
- return new UdporChecker(remote_app);
+ return new simgrid::mc::udpor::UdporChecker(args);
}
} // namespace simgrid::mc
