* 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 <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::udpor {
UdporChecker::UdporChecker(const std::vector<char*>& args) : Exploration(args)
{
/* Create initial data structures, if any ...*/
- XBT_INFO("Starting a UDPOR exploration");
// TODO: Initialize state structures for the search
}
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 the former paper described in [3]
- EventSet A, D;
- Configuration C;
- EventSet prev_exC;
-
- const auto initial_state = get_current_state();
- const auto initial_state_id = state_manager_.record_state(std::move(initial_state));
- const auto root_event = std::make_unique<UnfoldingEvent>(-1, "", EventSet(), initial_state_id);
- explore(std::move(C), std::move(A), std::move(D), {EventSet()}, root_event.get(), std::move(prev_exC));
+ // 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(std::move(C_root), EventSet(), EventSet(), std::move(initial_state), EventSet());
+
+ XBT_INFO("UDPOR exploration terminated -- model checking completed");
}
-void UdporChecker::explore(Configuration C, EventSet D, EventSet A, std::list<EventSet> max_evt_history,
- UnfoldingEvent* cur_evt, EventSet prev_exC)
+void UdporChecker::explore(Configuration C, EventSet D, EventSet A, std::unique_ptr<State> stateC, EventSet prev_exC)
{
// Perform the incremental computation of exC
- auto [exC, enC] = compute_extension(C, max_evt_history, *cur_evt, prev_exC);
+ //
+ // TODO: This method will have side effects on
+ // the unfolding, but the naming of the method
+ // suggests it is doesn't have side effects. We should
+ // reconcile this in the future
+ auto [exC, enC] = compute_extension(C, prev_exC);
// If enC is a subset of D, intuitively
// there aren't any enabled transitions
// TODO: Add verbose logging about which event is being explored
- observe_unfolding_event(*cur_evt);
- const auto next_state_id = record_newly_visited_state();
-
UnfoldingEvent* e = select_next_unfolding_event(A, enC);
- xbt_assert(e != nullptr, "UDPOR guarantees that an event will be chosen at each point in"
- "the search, yet no events were actually chosen");
- e->set_state_id(next_state_id);
+ 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");
- // TODO: Clean up configuration code before moving into the actual
- // implementations of everything
+ // Move the application into stateCe and actually make note of that state
+ move_to_stateCe(*stateC, *e);
+ auto stateCe = record_current_state();
- // Configuration is the same + event e
- // Ce = C + {e}
+ // Ce := C + {e}
Configuration Ce = C;
Ce.add_event(e);
- max_evt_history.push_back(Ce.get_maxmimal_events());
A.remove(e);
exC.remove(e);
// Explore(C + {e}, D, A \ {e})
- explore(Ce, D, std::move(A), max_evt_history, e, std::move(exC));
+ explore(Ce, D, std::move(A), std::move(stateCe), std::move(exC));
// D <-- D + {e}
D.insert(e);
auto J = compute_partial_alternative(D, C, K);
if (!J.empty()) {
J.subtract(C.get_events());
- max_evt_history.pop_back();
+
+ // 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(max_evt_history), cur_evt, std::move(prev_exC));
+ explore(C, D, std::move(J), std::move(stateC), std::move(prev_exC));
}
// D <-- D - {e}
clean_up_explore(e, C, D);
}
-std::tuple<EventSet, EventSet> UdporChecker::compute_extension(const Configuration& C,
- const std::list<EventSet>& max_evt_history,
- const UnfoldingEvent& cur_event,
- const EventSet& prev_exC) const
+std::tuple<EventSet, EventSet> UdporChecker::compute_extension(const Configuration& C, const EventSet& prev_exC) const
{
- // exC.remove(cur_event);
-
- // TODO: Compute extend() as it exists in tiny_simgrid
-
- // exC.subtract(C);
- return std::tuple<EventSet, EventSet>();
+ // 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, > : H }
+ UnfoldingEvent* e_cur = C.get_latest_event();
+ EventSet exC = prev_exC;
+ exC.remove(e_cur);
+
+ // ... fancy computations
+
+ EventSet enC;
+ return std::tuple<EventSet, EventSet>(exC, enC);
}
-State& UdporChecker::get_state_referenced_by(const UnfoldingEvent& event)
+void UdporChecker::move_to_stateCe(State& state, const UnfoldingEvent& e)
{
- const auto state_id = event.get_state_id();
- const auto wrapped_state = this->state_manager_.get_state(state_id);
- xbt_assert(wrapped_state != std::nullopt,
- "\n\n****** FATAL ERROR ******\n"
- "To each UDPOR event corresponds a state,"
- "but state %lu does not exist\n"
- "******************\n\n",
- state_id);
- return wrapped_state.value().get();
-}
+ const aid_t next_actor = e.get_transition()->aid_;
-void UdporChecker::observe_unfolding_event(const UnfoldingEvent& event)
-{
- auto& state = this->get_state_referenced_by(event);
- const aid_t next_actor = state.next_transition();
- xbt_assert(next_actor >= 0, "\n\n****** FATAL ERROR ******\n"
+ // 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");
+ "state was actually enabled. Please report this as a bug.\n"
+ "*********************************\n\n");
state.execute_next(next_actor);
}
-StateHandle UdporChecker::record_newly_visited_state()
+void UdporChecker::restore_program_state_to(const State& stateC)
{
- const auto next_state = this->get_current_state();
- const auto next_state_id = this->state_manager_.record_state(std::move(next_state));
+ // 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_id;
+
+ return next_state;
}
UnfoldingEvent* UdporChecker::select_next_unfolding_event(const EventSet& A, const EventSet& enC)
{
- // TODO: Actually select an event here
+ if (!enC.empty()) {
+ return *(enC.begin());
+ }
+
+ for (const auto& event : A) {
+ if (enC.contains(event)) {
+ return event;
+ }
+ }
return nullptr;
}
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;
}
