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CommDet shall become an extension of the SafetyChecker
[simgrid.git] / src / mc / api.cpp
index c41fab2..8bf2519 100644 (file)
@@ -1,14 +1,21 @@
+/* Copyright (c) 2020-2022. 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 "api.hpp"
 
 #include "src/kernel/activity/MailboxImpl.hpp"
 #include "src/kernel/activity/MutexImpl.hpp"
+#include "src/kernel/actor/SimcallObserver.hpp"
 #include "src/mc/Session.hpp"
-#include "src/mc/checker/SimcallObserver.hpp"
-#include "src/mc/mc_comm_pattern.hpp"
+#include "src/mc/checker/Checker.hpp"
+#include "src/mc/mc_base.hpp"
 #include "src/mc/mc_exit.hpp"
 #include "src/mc/mc_pattern.hpp"
 #include "src/mc/mc_private.hpp"
-#include "src/mc/remote/RemoteSimulation.hpp"
+#include "src/mc/remote/RemoteProcess.hpp"
+#include "src/surf/HostImpl.hpp"
 
 #include <xbt/asserts.h>
 #include <xbt/log.h>
 #endif
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(Api, mc, "Logging specific to MC Facade APIs ");
+XBT_LOG_EXTERNAL_CATEGORY(mc_global);
 
 using Simcall = simgrid::simix::Simcall;
 
 namespace simgrid {
 namespace mc {
 
-static inline const char* get_color(int id)
-{
-  static constexpr std::array<const char*, 13> colors{{"blue", "red", "green3", "goldenrod", "brown", "purple",
-                                                       "magenta", "turquoise4", "gray25", "forestgreen", "hotpink",
-                                                       "lightblue", "tan"}};
-  return colors[id % colors.size()];
-}
-
-static std::string pointer_to_string(void* pointer)
-{
-  return XBT_LOG_ISENABLED(Api, xbt_log_priority_verbose) ? xbt::string_printf("%p", pointer) : "(verbose only)";
-}
-
-static std::string buff_size_to_string(size_t buff_size)
-{
-  return XBT_LOG_ISENABLED(Api, xbt_log_priority_verbose) ? std::to_string(buff_size) : "(verbose only)";
-}
-
-static void simcall_translate(smx_simcall_t req,
-                              simgrid::mc::Remote<simgrid::kernel::activity::CommImpl>& buffered_comm);
-
-/* Search an enabled transition for the given process.
- *
- * This can be seen as an iterator returning the next transition of the process.
- *
- * We only consider the processes that are both
- *  - marked "to be interleaved" in their ActorState (controlled by the checker algorithm).
- *  - which simcall can currently be executed (like a comm where the other partner is already known)
- * Once we returned the last enabled transition of a process, it is marked done.
- *
- * Things can get muddled with the WAITANY and TESTANY simcalls, that are rewritten on the fly to a bunch of WAIT
- * (resp TEST) transitions using the transition.argument field to remember what was the last returned sub-transition.
- */
-static inline smx_simcall_t MC_state_choose_request_for_process(simgrid::mc::State* state, smx_actor_t actor)
-{
-  /* reset the outgoing transition */
-  simgrid::mc::ActorState* procstate = &state->actor_states_[actor->get_pid()];
-  state->transition_.pid_            = -1;
-  state->transition_.times_considered_ = -1;
-  state->transition_.textual[0]        = '\0';
-  state->executed_req_.call_         = Simcall::NONE;
-
-  if (not simgrid::mc::actor_is_enabled(actor))
-    return nullptr; // Not executable in the application
-
-  smx_simcall_t req = nullptr;
-  if (actor->simcall_.observer_ != nullptr) {
-    state->transition_.times_considered_ = procstate->times_considered;
-    procstate->times_considered++;
-    if (actor->simcall_.mc_max_consider_ <= procstate->times_considered)
-      procstate->set_done();
-    req = &actor->simcall_;
-  } else
-    switch (actor->simcall_.call_) {
-      case Simcall::COMM_WAITANY:
-        state->transition_.times_considered_ = -1;
-        while (procstate->times_considered < simcall_comm_waitany__get__count(&actor->simcall_)) {
-          if (simgrid::mc::request_is_enabled_by_idx(&actor->simcall_, procstate->times_considered)) {
-            state->transition_.times_considered_ = procstate->times_considered;
-            ++procstate->times_considered;
-            break;
-          }
-          ++procstate->times_considered;
-        }
-
-        if (procstate->times_considered >= simcall_comm_waitany__get__count(&actor->simcall_))
-          procstate->set_done();
-        if (state->transition_.times_considered_ != -1)
-          req = &actor->simcall_;
-        break;
-
-      case Simcall::COMM_TESTANY:
-        state->transition_.times_considered_ = -1;
-        while (procstate->times_considered < simcall_comm_testany__get__count(&actor->simcall_)) {
-          if (simgrid::mc::request_is_enabled_by_idx(&actor->simcall_, procstate->times_considered)) {
-            state->transition_.times_considered_ = procstate->times_considered;
-            ++procstate->times_considered;
-            break;
-          }
-          ++procstate->times_considered;
-        }
-
-        if (procstate->times_considered >= simcall_comm_testany__get__count(&actor->simcall_))
-          procstate->set_done();
-        if (state->transition_.times_considered_ != -1)
-          req = &actor->simcall_;
-        break;
-
-      case Simcall::COMM_WAIT: {
-        simgrid::mc::RemotePtr<simgrid::kernel::activity::CommImpl> remote_act =
-            remote(simcall_comm_wait__getraw__comm(&actor->simcall_));
-        simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_act;
-        mc_model_checker->get_remote_simulation().read(temp_act, remote_act);
-        const simgrid::kernel::activity::CommImpl* act = temp_act.get_buffer();
-        if (act->src_actor_.get() && act->dst_actor_.get())
-          state->transition_.times_considered_ = 0; // OK
-        else if (act->src_actor_.get() == nullptr && act->state_ == simgrid::kernel::activity::State::READY &&
-                 act->detached())
-          state->transition_.times_considered_ = 0; // OK
-        else
-          state->transition_.times_considered_ = -1; // timeout
-        procstate->set_done();
-        req = &actor->simcall_;
-        break;
-      }
-
-      default:
-        procstate->set_done();
-        state->transition_.times_considered_ = 0;
-        req                                  = &actor->simcall_;
-        break;
-    }
-  if (not req)
-    return nullptr;
-
-  state->transition_.pid_ = actor->get_pid();
-  state->executed_req_    = *req;
-
-  // Fetch the data of the request and translate it:
-  state->internal_req_ = *req;
-  state->internal_req_.mc_value_ = state->transition_.times_considered_;
-  simcall_translate(&state->internal_req_, state->internal_comm_);
-
-  return req;
-}
-
-static void simcall_translate(smx_simcall_t req,
-                              simgrid::mc::Remote<simgrid::kernel::activity::CommImpl>& buffered_comm)
-{
-  simgrid::kernel::activity::CommImpl* chosen_comm;
-
-  /* The waitany and testany request are transformed into a wait or test request over the corresponding communication
-   * action so it can be treated later by the dependence function. */
-  switch (req->call_) {
-    case Simcall::COMM_WAITANY:
-      req->call_  = Simcall::COMM_WAIT;
-      chosen_comm = mc_model_checker->get_remote_simulation().read(
-          remote(simcall_comm_waitany__get__comms(req) + req->mc_value_));
-
-      mc_model_checker->get_remote_simulation().read(buffered_comm, remote(chosen_comm));
-      simcall_comm_wait__set__comm(req, buffered_comm.get_buffer());
-      simcall_comm_wait__set__timeout(req, 0);
-      break;
-
-    case Simcall::COMM_TESTANY:
-      req->call_  = Simcall::COMM_TEST;
-      chosen_comm = mc_model_checker->get_remote_simulation().read(
-          remote(simcall_comm_testany__get__comms(req) + req->mc_value_));
-
-      mc_model_checker->get_remote_simulation().read(buffered_comm, remote(chosen_comm));
-      simcall_comm_test__set__comm(req, buffered_comm.get_buffer());
-      simcall_comm_test__set__result(req, req->mc_value_);
-      break;
-
-    case Simcall::COMM_WAIT:
-      chosen_comm = simcall_comm_wait__getraw__comm(req);
-      mc_model_checker->get_remote_simulation().read(buffered_comm, remote(chosen_comm));
-      simcall_comm_wait__set__comm(req, buffered_comm.get_buffer());
-      break;
-
-    case Simcall::COMM_TEST:
-      chosen_comm = simcall_comm_test__getraw__comm(req);
-      mc_model_checker->get_remote_simulation().read(buffered_comm, remote(chosen_comm));
-      simcall_comm_test__set__comm(req, buffered_comm.get_buffer());
-      break;
-
-    default:
-      /* No translation needed */
-      break;
-  }
-}
-
-simgrid::kernel::activity::CommImpl* Api::get_comm_or_nullptr(smx_simcall_t const r) const
-{
-  if (r->call_ == Simcall::COMM_WAIT)
-    return simcall_comm_wait__getraw__comm(r);
-  if (r->call_ == Simcall::COMM_TEST)
-    return simcall_comm_test__getraw__comm(r);
-  return nullptr;
-}
-
 /** Statically "upcast" a s_smx_actor_t into an ActorInformation
  *
  *  This gets 'actorInfo' from '&actorInfo->copy'. It upcasts in the
@@ -221,141 +48,36 @@ simgrid::mc::ActorInformation* Api::actor_info_cast(smx_actor_t actor) const
   return process_info;
 }
 
-// Does half the job
-bool Api::request_depend_asymmetric(smx_simcall_t r1, smx_simcall_t r2) const
-{
-  if (r1->call_ == Simcall::COMM_ISEND && r2->call_ == Simcall::COMM_IRECV)
-    return false;
-
-  if (r1->call_ == Simcall::COMM_IRECV && r2->call_ == Simcall::COMM_ISEND)
-    return false;
-
-  // Those are internal requests, we do not need indirection because those objects are copies:
-  auto comm1 = get_comm_or_nullptr(r1);
-  auto comm2 = get_comm_or_nullptr(r2);
-
-  if ((r1->call_ == Simcall::COMM_ISEND || r1->call_ == Simcall::COMM_IRECV) && r2->call_ == Simcall::COMM_WAIT) {
-    auto mbox1 = get_mbox_remote_addr(r1);
-    auto mbox2 = remote(comm2->mbox_cpy);
-
-    if (mbox1 != mbox2 && simcall_comm_wait__get__timeout(r2) <= 0)
-      return false;
-
-    if ((r1->issuer_ != comm2->src_actor_.get()) && (r1->issuer_ != comm2->dst_actor_.get()) &&
-        simcall_comm_wait__get__timeout(r2) <= 0)
-      return false;
-
-    if ((r1->call_ == Simcall::COMM_ISEND) && (comm2->type_ == kernel::activity::CommImpl::Type::SEND) &&
-        (comm2->src_buff_ != simcall_comm_isend__get__src_buff(r1)) && simcall_comm_wait__get__timeout(r2) <= 0)
-      return false;
-
-    if ((r1->call_ == Simcall::COMM_IRECV) && (comm2->type_ == kernel::activity::CommImpl::Type::RECEIVE) &&
-        (comm2->dst_buff_ != simcall_comm_irecv__get__dst_buff(r1)) && simcall_comm_wait__get__timeout(r2) <= 0)
-      return false;
-  }
-
-  /* FIXME: the following rule assumes that the result of the isend/irecv call is not stored in a buffer used in the
-   * test call. */
-#if 0
-  if((r1->call == Simcall::COMM_ISEND || r1->call == Simcall::COMM_IRECV)
-      &&  r2->call == Simcall::COMM_TEST)
-    return false;
-#endif
-
-  if (r1->call_ == Simcall::COMM_WAIT && (r2->call_ == Simcall::COMM_WAIT || r2->call_ == Simcall::COMM_TEST) &&
-      (comm1->src_actor_.get() == nullptr || comm1->dst_actor_.get() == nullptr))
-    return false;
-
-  if (r1->call_ == Simcall::COMM_TEST &&
-      (simcall_comm_test__get__comm(r1) == nullptr || comm1->src_buff_ == nullptr || comm1->dst_buff_ == nullptr))
-    return false;
-
-  if (r1->call_ == Simcall::COMM_TEST && r2->call_ == Simcall::COMM_WAIT && comm1->src_buff_ == comm2->src_buff_ &&
-      comm1->dst_buff_ == comm2->dst_buff_)
-    return false;
-
-  if (r1->call_ == Simcall::COMM_WAIT && r2->call_ == Simcall::COMM_TEST && comm1->src_buff_ != nullptr &&
-      comm1->dst_buff_ != nullptr && comm2->src_buff_ != nullptr && comm2->dst_buff_ != nullptr &&
-      comm1->dst_buff_ != comm2->src_buff_ && comm1->dst_buff_ != comm2->dst_buff_ &&
-      comm2->dst_buff_ != comm1->src_buff_)
-    return false;
-
-  return true;
-}
-
-bool Api::simcall_check_dependency(smx_simcall_t const req1, smx_simcall_t const req2) const
-{
-  const auto ISEND = Simcall::COMM_ISEND;
-  const auto IRECV = Simcall::COMM_IRECV;
-  const auto TEST  = Simcall::COMM_TEST;
-  const auto WAIT  = Simcall::COMM_WAIT;
-
-  if (req1->issuer_ == req2->issuer_)
-    return false;
-
-  /* The independence theorem only consider 4 simcalls. All others are dependent with anything. */
-  if (req1->call_ != ISEND && req1->call_ != IRECV && req1->call_ != TEST && req1->call_ != WAIT)
-    return true;
-  if (req2->call_ != ISEND && req2->call_ != IRECV && req2->call_ != TEST && req2->call_ != WAIT)
-    return true;
-
-  /* Timeouts in wait transitions are not considered by the independence theorem, thus assumed dependent */
-  if ((req1->call_ == WAIT && simcall_comm_wait__get__timeout(req1) > 0) ||
-      (req2->call_ == WAIT && simcall_comm_wait__get__timeout(req2) > 0))
-    return true;
-
-  if (req1->call_ != req2->call_)
-    return request_depend_asymmetric(req1, req2) && request_depend_asymmetric(req2, req1);
-
-  // Those are internal requests, we do not need indirection because those objects are copies:
-  const auto comm1 = get_comm_or_nullptr(req1);
-  const auto comm2 = get_comm_or_nullptr(req2);
-
-  switch (req1->call_) {
-    case Simcall::COMM_ISEND:
-      return simcall_comm_isend__get__mbox(req1) == simcall_comm_isend__get__mbox(req2);
-    case Simcall::COMM_IRECV:
-      return simcall_comm_irecv__get__mbox(req1) == simcall_comm_irecv__get__mbox(req2);
-    case Simcall::COMM_WAIT:
-      if (comm1->src_buff_ == comm2->src_buff_ && comm1->dst_buff_ == comm2->dst_buff_)
-        return false;
-      if (comm1->src_buff_ != nullptr && comm1->dst_buff_ != nullptr && comm2->src_buff_ != nullptr &&
-          comm2->dst_buff_ != nullptr && comm1->dst_buff_ != comm2->src_buff_ && comm1->dst_buff_ != comm2->dst_buff_ &&
-          comm2->dst_buff_ != comm1->src_buff_)
-        return false;
-      return true;
-    default:
-      return true;
-  }
-}
-
 xbt::string const& Api::get_actor_host_name(smx_actor_t actor) const
 {
   if (mc_model_checker == nullptr)
     return actor->get_host()->get_name();
 
-  const simgrid::mc::RemoteSimulation* process = &mc_model_checker->get_remote_simulation();
+  const simgrid::mc::RemoteProcess* process = &mc_model_checker->get_remote_process();
 
   // Read the simgrid::xbt::string in the MCed process:
   simgrid::mc::ActorInformation* info = actor_info_cast(actor);
-  auto remote_string_address =
-      remote(reinterpret_cast<const simgrid::xbt::string_data*>(&actor->get_host()->get_name()));
-  simgrid::xbt::string_data remote_string = process->read(remote_string_address);
-  std::vector<char> hostname(remote_string.len + 1);
-  // no need to read the terminating null byte, and thus hostname[remote_string.len] is guaranteed to be '\0'
-  process->read_bytes(hostname.data(), remote_string.len, remote(remote_string.data));
-  info->hostname = &mc_model_checker->get_host_name(hostname.data());
+
+  if (not info->hostname) {
+    Remote<s4u::Host> temp_host = process->read(remote(actor->get_host()));
+    auto remote_string_address  = remote(&xbt::string::to_string_data(temp_host.get_buffer()->get_impl()->get_name()));
+    simgrid::xbt::string_data remote_string = process->read(remote_string_address);
+    std::vector<char> hostname(remote_string.len + 1);
+    // no need to read the terminating null byte, and thus hostname[remote_string.len] is guaranteed to be '\0'
+    process->read_bytes(hostname.data(), remote_string.len, remote(remote_string.data));
+    info->hostname = &mc_model_checker->get_host_name(hostname.data());
+  }
   return *info->hostname;
 }
 
-std::string Api::get_actor_name(smx_actor_t actor) const
+xbt::string const& Api::get_actor_name(smx_actor_t actor) const
 {
   if (mc_model_checker == nullptr)
-    return actor->get_cname();
+    return actor->get_name();
 
   simgrid::mc::ActorInformation* info = actor_info_cast(actor);
   if (info->name.empty()) {
-    const simgrid::mc::RemoteSimulation* process = &mc_model_checker->get_remote_simulation();
+    const simgrid::mc::RemoteProcess* process = &mc_model_checker->get_remote_process();
 
     simgrid::xbt::string_data string_data = simgrid::xbt::string::to_string_data(actor->name_);
     info->name = process->read_string(remote(string_data.data), string_data.len);
@@ -369,7 +91,7 @@ std::string Api::get_actor_string(smx_actor_t actor) const
   if (actor) {
     res = "(" + std::to_string(actor->get_pid()) + ")";
     if (actor->get_host())
-      res += std::string(get_actor_host_name(actor)) + " (" + get_actor_name(actor) + ")";
+      res += std::string(get_actor_host_name(actor)) + " (" + std::string(get_actor_name(actor)) + ")";
     else
       res += get_actor_name(actor);
   } else
@@ -385,45 +107,59 @@ std::string Api::get_actor_dot_label(smx_actor_t actor) const
   return res;
 }
 
-void Api::initialize(char** argv) const
+simgrid::mc::Checker* Api::initialize(char** argv, simgrid::mc::CheckerAlgorithm algo) const
 {
-  simgrid::mc::session = new simgrid::mc::Session([argv] {
+  auto session = new simgrid::mc::Session([argv] {
     int i = 1;
     while (argv[i] != nullptr && argv[i][0] == '-')
       i++;
     xbt_assert(argv[i] != nullptr,
                "Unable to find a binary to exec on the command line. Did you only pass config flags?");
     execvp(argv[i], argv + i);
-    xbt_die("The model-checked process failed to exec(): %s", strerror(errno));
+    xbt_die("The model-checked process failed to exec(%s): %s", argv[i], strerror(errno));
   });
-}
 
-std::vector<simgrid::mc::ActorInformation>& Api::get_actors() const
-{
-  return mc_model_checker->get_remote_simulation().actors();
+  simgrid::mc::Checker* checker;
+  switch (algo) {
+    case CheckerAlgorithm::CommDeterminism:
+      checker = simgrid::mc::create_communication_determinism_checker(session);
+      break;
+
+    case CheckerAlgorithm::UDPOR:
+      checker = simgrid::mc::create_udpor_checker(session);
+      break;
+
+    case CheckerAlgorithm::Safety:
+      checker = simgrid::mc::create_safety_checker(session);
+      break;
+
+    case CheckerAlgorithm::Liveness:
+      checker = simgrid::mc::create_liveness_checker(session);
+      break;
+
+    default:
+      THROW_IMPOSSIBLE;
+  }
+
+  // FIXME: session and checker are never deleted
+  simgrid::mc::session_singleton = session;
+  mc_model_checker->setChecker(checker);
+  return checker;
 }
 
-bool Api::actor_is_enabled(aid_t pid) const
+std::vector<simgrid::mc::ActorInformation>& Api::get_actors() const
 {
-  return session->actor_is_enabled(pid);
+  return mc_model_checker->get_remote_process().actors();
 }
 
 unsigned long Api::get_maxpid() const
 {
-  static const char* name = nullptr;
-  if (not name) {
-    name = "simgrid::kernel::actor::maxpid";
-    if (mc_model_checker->get_remote_simulation().find_variable(name) == nullptr)
-      name = "maxpid"; // We seem to miss the namespaces when compiling with GCC
-  }
-  unsigned long maxpid;
-  mc_model_checker->get_remote_simulation().read_variable(name, &maxpid, sizeof(maxpid));
-  return maxpid;
+  return mc_model_checker->get_remote_process().get_maxpid();
 }
 
 int Api::get_actors_size() const
 {
-  return mc_model_checker->get_remote_simulation().actors().size();
+  return mc_model_checker->get_remote_process().actors().size();
 }
 
 RemotePtr<kernel::activity::CommImpl> Api::get_comm_isend_raw_addr(smx_simcall_t request) const
@@ -431,60 +167,55 @@ RemotePtr<kernel::activity::CommImpl> Api::get_comm_isend_raw_addr(smx_simcall_t
   return remote(static_cast<kernel::activity::CommImpl*>(simcall_comm_isend__getraw__result(request)));
 }
 
-RemotePtr<kernel::activity::CommImpl> Api::get_comm_wait_raw_addr(smx_simcall_t request) const
-{
-  return remote(simcall_comm_wait__getraw__comm(request));
-}
-
 RemotePtr<kernel::activity::CommImpl> Api::get_comm_waitany_raw_addr(smx_simcall_t request, int value) const
 {
   auto addr      = simcall_comm_waitany__getraw__comms(request) + value;
-  auto comm_addr = mc_model_checker->get_remote_simulation().read(remote(addr));
+  auto comm_addr = mc_model_checker->get_remote_process().read(remote(addr));
   return RemotePtr<kernel::activity::CommImpl>(static_cast<kernel::activity::CommImpl*>(comm_addr));
 }
 
 std::string Api::get_pattern_comm_rdv(RemotePtr<kernel::activity::CommImpl> const& addr) const
 {
   Remote<kernel::activity::CommImpl> temp_activity;
-  mc_model_checker->get_remote_simulation().read(temp_activity, addr);
+  mc_model_checker->get_remote_process().read(temp_activity, addr);
   const kernel::activity::CommImpl* activity = temp_activity.get_buffer();
 
-  char* remote_name = mc_model_checker->get_remote_simulation().read<char*>(RemotePtr<char*>(
+  char* remote_name = mc_model_checker->get_remote_process().read<char*>(RemotePtr<char*>(
       (uint64_t)(activity->get_mailbox() ? &activity->get_mailbox()->get_name() : &activity->mbox_cpy->get_name())));
-  auto rdv          = mc_model_checker->get_remote_simulation().read_string(RemotePtr<char>(remote_name));
+  auto rdv          = mc_model_checker->get_remote_process().read_string(RemotePtr<char>(remote_name));
   return rdv;
 }
 
 unsigned long Api::get_pattern_comm_src_proc(RemotePtr<kernel::activity::CommImpl> const& addr) const
 {
   Remote<kernel::activity::CommImpl> temp_activity;
-  mc_model_checker->get_remote_simulation().read(temp_activity, addr);
+  mc_model_checker->get_remote_process().read(temp_activity, addr);
   const kernel::activity::CommImpl* activity = temp_activity.get_buffer();
   auto src_proc =
-      mc_model_checker->get_remote_simulation().resolve_actor(mc::remote(activity->src_actor_.get()))->get_pid();
+      mc_model_checker->get_remote_process().resolve_actor(mc::remote(activity->src_actor_.get()))->get_pid();
   return src_proc;
 }
 
 unsigned long Api::get_pattern_comm_dst_proc(RemotePtr<kernel::activity::CommImpl> const& addr) const
 {
   Remote<kernel::activity::CommImpl> temp_activity;
-  mc_model_checker->get_remote_simulation().read(temp_activity, addr);
+  mc_model_checker->get_remote_process().read(temp_activity, addr);
   const kernel::activity::CommImpl* activity = temp_activity.get_buffer();
   auto src_proc =
-      mc_model_checker->get_remote_simulation().resolve_actor(mc::remote(activity->dst_actor_.get()))->get_pid();
+      mc_model_checker->get_remote_process().resolve_actor(mc::remote(activity->dst_actor_.get()))->get_pid();
   return src_proc;
 }
 
 std::vector<char> Api::get_pattern_comm_data(RemotePtr<kernel::activity::CommImpl> const& addr) const
 {
   simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
-  mc_model_checker->get_remote_simulation().read(temp_comm, addr);
+  mc_model_checker->get_remote_process().read(temp_comm, addr);
   const simgrid::kernel::activity::CommImpl* comm = temp_comm.get_buffer();
 
   std::vector<char> buffer{};
   if (comm->src_buff_ != nullptr) {
     buffer.resize(comm->src_buff_size_);
-    mc_model_checker->get_remote_simulation().read_bytes(buffer.data(), buffer.size(), remote(comm->src_buff_));
+    mc_model_checker->get_remote_process().read_bytes(buffer.data(), buffer.size(), remote(comm->src_buff_));
   }
   return buffer;
 }
@@ -492,69 +223,61 @@ std::vector<char> Api::get_pattern_comm_data(RemotePtr<kernel::activity::CommImp
 #if HAVE_SMPI
 bool Api::check_send_request_detached(smx_simcall_t const& simcall) const
 {
-  simgrid::smpi::Request mpi_request;
-  mc_model_checker->get_remote_simulation().read(
-      &mpi_request, remote(static_cast<smpi::Request*>(simcall_comm_isend__get__data(simcall))));
-  return mpi_request.detached();
+  Remote<simgrid::smpi::Request> mpi_request;
+  mc_model_checker->get_remote_process().read(
+      mpi_request, remote(static_cast<smpi::Request*>(simcall_comm_isend__get__data(simcall))));
+  return mpi_request.get_buffer()->detached();
 }
 #endif
 
 smx_actor_t Api::get_src_actor(RemotePtr<kernel::activity::CommImpl> const& comm_addr) const
 {
   simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
-  mc_model_checker->get_remote_simulation().read(temp_comm, comm_addr);
+  mc_model_checker->get_remote_process().read(temp_comm, comm_addr);
   const simgrid::kernel::activity::CommImpl* comm = temp_comm.get_buffer();
 
-  auto src_proc = mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(comm->src_actor_.get()));
+  auto src_proc = mc_model_checker->get_remote_process().resolve_actor(simgrid::mc::remote(comm->src_actor_.get()));
   return src_proc;
 }
 
 smx_actor_t Api::get_dst_actor(RemotePtr<kernel::activity::CommImpl> const& comm_addr) const
 {
   simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
-  mc_model_checker->get_remote_simulation().read(temp_comm, comm_addr);
+  mc_model_checker->get_remote_process().read(temp_comm, comm_addr);
   const simgrid::kernel::activity::CommImpl* comm = temp_comm.get_buffer();
 
-  auto dst_proc = mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(comm->dst_actor_.get()));
+  auto dst_proc = mc_model_checker->get_remote_process().resolve_actor(simgrid::mc::remote(comm->dst_actor_.get()));
   return dst_proc;
 }
 
 std::size_t Api::get_remote_heap_bytes() const
 {
-  RemoteSimulation& process = mc_model_checker->get_remote_simulation();
+  RemoteProcess& process    = mc_model_checker->get_remote_process();
   auto heap_bytes_used      = mmalloc_get_bytes_used_remote(process.get_heap()->heaplimit, process.get_malloc_info());
   return heap_bytes_used;
 }
 
-void Api::session_initialize() const
-{
-  session->initialize();
-}
-
 void Api::mc_inc_visited_states() const
 {
   mc_model_checker->visited_states++;
 }
 
-void Api::mc_inc_executed_trans() const
-{
-  mc_model_checker->executed_transitions++;
-}
-
 unsigned long Api::mc_get_visited_states() const
 {
   return mc_model_checker->visited_states;
 }
 
-unsigned long Api::mc_get_executed_trans() const
-{
-  return mc_model_checker->executed_transitions;
-}
-
 void Api::mc_check_deadlock() const
 {
   if (mc_model_checker->checkDeadlock()) {
-    MC_show_deadlock();
+    XBT_CINFO(mc_global, "**************************");
+    XBT_CINFO(mc_global, "*** DEADLOCK DETECTED ***");
+    XBT_CINFO(mc_global, "**************************");
+    XBT_CINFO(mc_global, "Counter-example execution trace:");
+    for (auto const& s : mc_model_checker->getChecker()->get_textual_trace())
+      XBT_CINFO(mc_global, "  %s", s.c_str());
+    XBT_INFO("Path = %s", mc_model_checker->getChecker()->get_record_trace().to_string().c_str());
+    simgrid::mc::session_singleton->log_state();
     throw DeadlockError();
   }
 }
@@ -576,21 +299,16 @@ smx_actor_t Api::simcall_get_issuer(s_smx_simcall const* req) const
   auto address = simgrid::mc::remote(req->issuer_);
 
   // Lookup by address:
-  for (auto& actor : mc_model_checker->get_remote_simulation().actors())
+  for (auto& actor : mc_model_checker->get_remote_process().actors())
     if (actor.address == address)
       return actor.copy.get_buffer();
-  for (auto& actor : mc_model_checker->get_remote_simulation().dead_actors())
+  for (auto& actor : mc_model_checker->get_remote_process().dead_actors())
     if (actor.address == address)
       return actor.copy.get_buffer();
 
   xbt_die("Issuer not found");
 }
 
-long Api::simcall_get_actor_id(s_smx_simcall const* req) const
-{
-  return simcall_get_issuer(req)->get_pid();
-}
-
 RemotePtr<kernel::activity::MailboxImpl> Api::get_mbox_remote_addr(smx_simcall_t const req) const
 {
   if (req->call_ == Simcall::COMM_ISEND)
@@ -609,300 +327,43 @@ RemotePtr<kernel::activity::ActivityImpl> Api::get_comm_remote_addr(smx_simcall_
   THROW_IMPOSSIBLE;
 }
 
-bool Api::mc_is_null() const
-{
-  auto is_null = (mc_model_checker == nullptr) ? true : false;
-  return is_null;
-}
-
-Checker* Api::mc_get_checker() const
-{
-  return mc_model_checker->getChecker();
-}
-
-void Api::set_checker(Checker* const checker) const
-{
-  xbt_assert(mc_model_checker);
-  xbt_assert(mc_model_checker->getChecker() == nullptr);
-  mc_model_checker->setChecker(checker);
-}
-
-void Api::handle_simcall(Transition const& transition) const
-{
-  mc_model_checker->handle_simcall(transition);
-}
-
-void Api::mc_wait_for_requests() const
-{
-  mc_model_checker->wait_for_requests();
-}
-
 void Api::mc_exit(int status) const
 {
   mc_model_checker->exit(status);
 }
 
-void Api::dump_record_path() const
-{
-  simgrid::mc::dumpRecordPath();
-}
-
-smx_simcall_t Api::mc_state_choose_request(simgrid::mc::State* state) const
-{
-  for (auto& actor : mc_model_checker->get_remote_simulation().actors()) {
-    /* Only consider the actors that were marked as interleaving by the checker algorithm */
-    if (not state->actor_states_[actor.copy.get_buffer()->get_pid()].is_todo())
-      continue;
-
-    smx_simcall_t res = MC_state_choose_request_for_process(state, actor.copy.get_buffer());
-    if (res)
-      return res;
-  }
-  return nullptr;
-}
-
-std::list<transition_detail_t> Api::get_enabled_transitions(simgrid::mc::State* state) const
-{
-  std::list<transition_detail_t> tr_list{};
-
-  for (auto& actor : mc_model_checker->get_remote_simulation().actors()) {
-    auto actor_pid  = actor.copy.get_buffer()->get_pid();
-    auto actor_impl = actor.copy.get_buffer();
-
-    // Only consider the actors that were marked as interleaving by the checker algorithm
-    if (not state->actor_states_[actor_pid].is_todo())
-      continue;
-    // Not executable in the application
-    if (not simgrid::mc::actor_is_enabled(actor_impl))
-      continue;
-
-    auto transition       = std::make_unique<s_transition_detail>();
-    Simcall simcall_call  = actor_impl->simcall_.call_;
-    smx_simcall_t simcall = &actor_impl->simcall_;
-    transition->call_     = simcall_call;
-    switch (simcall_call) {
-      case Simcall::COMM_ISEND:
-      case Simcall::COMM_IRECV:
-        transition->mbox_remote_addr = get_mbox_remote_addr(simcall);
-        transition->comm_remote_addr = get_comm_remote_addr(simcall);
-        break;
-
-      default:
-        break;
-    }
-    tr_list.emplace_back(std::move(transition));
-  }
-  
-  return tr_list;
-}
-
-std::string Api::request_to_string(smx_simcall_t req, int value) const
-{
-  xbt_assert(mc_model_checker != nullptr, "Must be called from MCer");
-
-  std::string type;
-  std::string args;
-
-  smx_actor_t issuer = simcall_get_issuer(req);
-
-  if (issuer->simcall_.observer_ != nullptr)
-    return mc_model_checker->simcall_to_string(issuer->get_pid(), value);
-
-  switch (req->call_) {
-    case Simcall::COMM_ISEND:
-      type = "iSend";
-      args = "src=" + get_actor_string(issuer);
-      args += ", buff=" + pointer_to_string(simcall_comm_isend__get__src_buff(req));
-      args += ", size=" + buff_size_to_string(simcall_comm_isend__get__src_buff_size(req));
-      break;
-
-    case Simcall::COMM_IRECV: {
-      size_t* remote_size = simcall_comm_irecv__get__dst_buff_size(req);
-      size_t size         = 0;
-      if (remote_size)
-        mc_model_checker->get_remote_simulation().read_bytes(&size, sizeof(size), remote(remote_size));
-
-      type = "iRecv";
-      args = "dst=" + get_actor_string(issuer);
-      args += ", buff=" + pointer_to_string(simcall_comm_irecv__get__dst_buff(req));
-      args += ", size=" + buff_size_to_string(size);
-      break;
-    }
-
-    case Simcall::COMM_WAIT: {
-      simgrid::kernel::activity::CommImpl* remote_act = simcall_comm_wait__getraw__comm(req);
-      if (value == -1) {
-        type = "WaitTimeout";
-        args = "comm=" + pointer_to_string(remote_act);
-      } else {
-        type = "Wait";
-
-        simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_activity;
-        const simgrid::kernel::activity::CommImpl* act;
-        mc_model_checker->get_remote_simulation().read(temp_activity, remote(remote_act));
-        act = temp_activity.get_buffer();
-
-        smx_actor_t src_proc =
-            mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(act->src_actor_.get()));
-        smx_actor_t dst_proc =
-            mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(act->dst_actor_.get()));
-        args = "comm=" + pointer_to_string(remote_act);
-        args += " [" + get_actor_string(src_proc) + "-> " + get_actor_string(dst_proc) + "]";
-      }
-      break;
-    }
-
-    case Simcall::COMM_TEST: {
-      simgrid::kernel::activity::CommImpl* remote_act = simcall_comm_test__getraw__comm(req);
-      simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_activity;
-      const simgrid::kernel::activity::CommImpl* act;
-      mc_model_checker->get_remote_simulation().read(temp_activity, remote(remote_act));
-      act = temp_activity.get_buffer();
-
-      if (act->src_actor_.get() == nullptr || act->dst_actor_.get() == nullptr) {
-        type = "Test FALSE";
-        args = "comm=" + pointer_to_string(remote_act);
-      } else {
-        type = "Test TRUE";
-
-        smx_actor_t src_proc =
-            mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(act->src_actor_.get()));
-        smx_actor_t dst_proc =
-            mc_model_checker->get_remote_simulation().resolve_actor(simgrid::mc::remote(act->dst_actor_.get()));
-        args = "comm=" + pointer_to_string(remote_act);
-        args += " [" + get_actor_string(src_proc) + " -> " + get_actor_string(dst_proc) + "]";
-      }
-      break;
-    }
-
-    case Simcall::COMM_WAITANY: {
-      type         = "WaitAny";
-      size_t count = simcall_comm_waitany__get__count(req);
-      if (count > 0) {
-        simgrid::kernel::activity::CommImpl* remote_sync;
-        remote_sync =
-            mc_model_checker->get_remote_simulation().read(remote(simcall_comm_waitany__get__comms(req) + value));
-        args = "comm=" + pointer_to_string(remote_sync) + xbt::string_printf("(%d of %zu)", value + 1, count);
-      } else
-        args = "comm at idx " + std::to_string(value);
-      break;
-    }
-
-    case Simcall::COMM_TESTANY:
-      if (value == -1) {
-        type = "TestAny FALSE";
-        args = "-";
-      } else {
-        type = "TestAny";
-        args = xbt::string_printf("(%d of %zu)", value + 1, simcall_comm_testany__get__count(req));
-      }
-      break;
-
-    default:
-      type = SIMIX_simcall_name(req->call_);
-      args = "??";
-      break;
-  }
-
-  return "[" + get_actor_string(issuer) + "] " + type + "(" + args + ")";
-}
-
-std::string Api::request_get_dot_output(smx_simcall_t req, int value) const
+std::string Api::request_get_dot_output(const Transition* t) const
 {
-  const smx_actor_t issuer = simcall_get_issuer(req);
-  const char* color        = get_color(issuer->get_pid() - 1);
-
-  std::string label;
+  static constexpr std::array<const char*, 13> colors{{"blue", "red", "green3", "goldenrod", "brown", "purple",
+                                                       "magenta", "turquoise4", "gray25", "forestgreen", "hotpink",
+                                                       "lightblue", "tan"}};
+  const char* color = colors[(t->aid_ - 1) % colors.size()];
 
-  if (req->observer_ != nullptr) {
-    label = mc_model_checker->simcall_dot_label(issuer->get_pid(), value);
-  } else
-    switch (req->call_) {
-      case Simcall::COMM_ISEND:
-        label = "[" + get_actor_dot_label(issuer) + "] iSend";
-        break;
-
-      case Simcall::COMM_IRECV:
-        label = "[" + get_actor_dot_label(issuer) + "] iRecv";
-        break;
-
-      case Simcall::COMM_WAIT:
-        if (value == -1) {
-          label = "[" + get_actor_dot_label(issuer) + "] WaitTimeout";
-        } else {
-          kernel::activity::ActivityImpl* remote_act = simcall_comm_wait__getraw__comm(req);
-          Remote<kernel::activity::CommImpl> temp_comm;
-          mc_model_checker->get_remote_simulation().read(temp_comm,
-                                                         remote(static_cast<kernel::activity::CommImpl*>(remote_act)));
-          const kernel::activity::CommImpl* comm = temp_comm.get_buffer();
-
-          const kernel::actor::ActorImpl* src_proc =
-              mc_model_checker->get_remote_simulation().resolve_actor(mc::remote(comm->src_actor_.get()));
-          const kernel::actor::ActorImpl* dst_proc =
-              mc_model_checker->get_remote_simulation().resolve_actor(mc::remote(comm->dst_actor_.get()));
-          label = "[" + get_actor_dot_label(issuer) + "] Wait";
-          label += " [(" + std::to_string(src_proc ? src_proc->get_pid() : 0) + ")";
-          label += "->(" + std::to_string(dst_proc ? dst_proc->get_pid() : 0) + ")]";
-        }
-        break;
-
-      case Simcall::COMM_TEST: {
-        kernel::activity::ActivityImpl* remote_act = simcall_comm_test__getraw__comm(req);
-        Remote<simgrid::kernel::activity::CommImpl> temp_comm;
-        mc_model_checker->get_remote_simulation().read(temp_comm,
-                                                       remote(static_cast<kernel::activity::CommImpl*>(remote_act)));
-        const kernel::activity::CommImpl* comm = temp_comm.get_buffer();
-        if (comm->src_actor_.get() == nullptr || comm->dst_actor_.get() == nullptr) {
-          label = "[" + get_actor_dot_label(issuer) + "] Test FALSE";
-        } else {
-          label = "[" + get_actor_dot_label(issuer) + "] Test TRUE";
-        }
-        break;
-      }
-
-      case Simcall::COMM_WAITANY:
-        label = "[" + get_actor_dot_label(issuer) + "] WaitAny";
-        label += xbt::string_printf(" [%d of %zu]", value + 1, simcall_comm_waitany__get__count(req));
-        break;
-
-      case Simcall::COMM_TESTANY:
-        if (value == -1) {
-          label = "[" + get_actor_dot_label(issuer) + "] TestAny FALSE";
-        } else {
-          label = "[" + get_actor_dot_label(issuer) + "] TestAny TRUE";
-          label += xbt::string_printf(" [%d of %zu]", value + 1, simcall_comm_testany__get__count(req));
-        }
-        break;
-
-      default:
-        THROW_UNIMPLEMENTED;
-    }
-
-  return "label = \"" + label + "\", color = " + color + ", fontcolor = " + color;
+  return "label = \"" + t->dot_label() + "\", color = " + color + ", fontcolor = " + color;
 }
 
 #if HAVE_SMPI
 int Api::get_smpi_request_tag(smx_simcall_t const& simcall, simgrid::simix::Simcall type) const
 {
-  simgrid::smpi::Request mpi_request;
   void* simcall_data = nullptr;
   if (type == Simcall::COMM_ISEND)
     simcall_data = simcall_comm_isend__get__data(simcall);
   else if (type == Simcall::COMM_IRECV)
     simcall_data = simcall_comm_irecv__get__data(simcall);
-  mc_model_checker->get_remote_simulation().read(&mpi_request, remote(static_cast<smpi::Request*>(simcall_data)));
-  return mpi_request.tag();
+  Remote<simgrid::smpi::Request> mpi_request;
+  mc_model_checker->get_remote_process().read(mpi_request, remote(static_cast<smpi::Request*>(simcall_data)));
+  return mpi_request.get_buffer()->tag();
 }
 #endif
 
 void Api::restore_state(std::shared_ptr<simgrid::mc::Snapshot> system_state) const
 {
-  system_state->restore(&mc_model_checker->get_remote_simulation());
+  system_state->restore(&mc_model_checker->get_remote_process());
 }
 
 void Api::log_state() const
 {
-  session->log_state();
+  session_singleton->log_state();
 }
 
 bool Api::snapshot_equal(const Snapshot* s1, const Snapshot* s2) const
@@ -910,7 +371,7 @@ bool Api::snapshot_equal(const Snapshot* s1, const Snapshot* s2) const
   return simgrid::mc::snapshot_equal(s1, s2);
 }
 
-simgrid::mc::Snapshot* Api::take_snapshot(int num_state) const
+simgrid::mc::Snapshot* Api::take_snapshot(long num_state) const
 {
   auto snapshot = new simgrid::mc::Snapshot(num_state);
   return snapshot;
@@ -918,27 +379,16 @@ simgrid::mc::Snapshot* Api::take_snapshot(int num_state) const
 
 void Api::s_close() const
 {
-  session->close();
+  session_singleton->close();
 }
 
-void Api::restore_initial_state() const
-{
-  session->restore_initial_state();
-}
-
-void Api::execute(Transition& transition, smx_simcall_t simcall) const
-{
-  /* FIXME: once all simcalls have observers, kill the simcall parameter and use mc_model_checker->simcall_to_string() */
-  transition.textual = request_to_string(simcall, transition.times_considered_);
-  session->execute(transition);
-}
-
-#if SIMGRID_HAVE_MC
 void Api::automaton_load(const char* file) const
 {
-  MC_automaton_load(file);
+  if (simgrid::mc::property_automaton == nullptr)
+    simgrid::mc::property_automaton = xbt_automaton_new();
+
+  xbt_automaton_load(simgrid::mc::property_automaton, file);
 }
-#endif
 
 std::vector<int> Api::automaton_propositional_symbol_evaluate() const
 {