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CommDet: reimplement on top of transitions. Don't mess with requests anymore
[simgrid.git] / src / mc / checker / CommunicationDeterminismChecker.cpp
index e40236d8557dc3a5235ad8b6e76f95df9b3b1454..c47b508d0672008db15a5b3a41001acde70ceb5d 100644 (file)
-/* Copyright (c) 2008-2019. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2008-2022. 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 "src/mc/checker/CommunicationDeterminismChecker.hpp"
 #include "src/kernel/activity/MailboxImpl.hpp"
-#include "src/mc/VisitedState.hpp"
+#include "src/mc/Session.hpp"
+#include "src/mc/api/TransitionComm.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/mc_request.hpp"
-#include "src/mc/mc_smx.hpp"
-#include "src/mc/mc_state.hpp"
-#include "src/mc/remote/Client.hpp"
-
-#if HAVE_SMPI
-#include "smpi_request.hpp"
-#endif
 
 #include <cstdint>
 
-using simgrid::mc::remote;
+using api = simgrid::mc::Api;
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_comm_determinism, mc, "Logging specific to MC communication determinism detection");
 
-/********** Global variables **********/
+namespace simgrid {
+namespace mc {
+
+enum class CallType { NONE, SEND, RECV, WAIT, WAITANY };
+enum class CommPatternDifference { NONE, TYPE, MBOX, TAG, SRC_PROC, DST_PROC, DATA_SIZE };
+enum class PatternCommunicationType {
+  none    = 0,
+  send    = 1,
+  receive = 2,
+};
+
+class PatternCommunication {
+public:
+  int num = 0;
+  uintptr_t comm_addr           = 0;
+  PatternCommunicationType type = PatternCommunicationType::send;
+  unsigned long src_proc        = 0;
+  unsigned long dst_proc        = 0;
+  unsigned mbox                 = 0;
+  unsigned size                 = 0;
+  int tag   = 0;
+  int index = 0;
+
+  PatternCommunication dup() const
+  {
+    simgrid::mc::PatternCommunication res;
+    // num?
+    res.comm_addr = this->comm_addr;
+    res.type      = this->type;
+    // src_proc?
+    // dst_proc?
+    res.dst_proc = this->dst_proc;
+    res.mbox     = this->mbox;
+    // tag?
+    res.index = this->index;
+    return res;
+  }
+};
+
+struct PatternCommunicationList {
+  unsigned int index_comm = 0;
+  std::vector<std::unique_ptr<simgrid::mc::PatternCommunication>> list;
+};
+
+/********** Checker extension **********/
+
+struct CommDetExtension {
+  static simgrid::xbt::Extension<simgrid::mc::Checker, CommDetExtension> EXTENSION_ID;
+
+  CommDetExtension()
+  {
+    const unsigned long maxpid = api::get().get_maxpid();
+
+    initial_communications_pattern.resize(maxpid);
+    incomplete_communications_pattern.resize(maxpid);
+  }
+
+  std::vector<simgrid::mc::PatternCommunicationList> initial_communications_pattern;
+  std::vector<std::vector<simgrid::mc::PatternCommunication*>> incomplete_communications_pattern;
+
+  bool initial_communications_pattern_done = false;
+  bool recv_deterministic                  = true;
+  bool send_deterministic                  = true;
+  std::string send_diff;
+  std::string recv_diff;
+
+  void restore_communications_pattern(const simgrid::mc::State* state);
+  void deterministic_comm_pattern(aid_t process, const PatternCommunication* comm, bool backtracking);
+  void get_comm_pattern(const Transition* transition, bool backtracking);
+  void complete_comm_pattern(const CommWaitTransition* transition, bool backtracking);
+  void handle_comm_pattern(const Transition* transition, bool backtracking);
+};
+simgrid::xbt::Extension<simgrid::mc::Checker, CommDetExtension> CommDetExtension::EXTENSION_ID;
+/********** State Extension ***********/
+
+class StateCommDet {
+  CommDetExtension* checker_;
+
+public:
+  std::vector<std::vector<simgrid::mc::PatternCommunication>> incomplete_comm_pattern_;
+  std::vector<unsigned> communication_indices_;
+
+  static simgrid::xbt::Extension<simgrid::mc::State, StateCommDet> EXTENSION_ID;
+  explicit StateCommDet(CommDetExtension* checker) : checker_(checker)
+  {
+    copy_incomplete_comm_pattern();
+    copy_index_comm_pattern();
+  }
 
-xbt_dynar_t initial_communications_pattern;
-xbt_dynar_t incomplete_communications_pattern;
+  void copy_incomplete_comm_pattern()
+  {
+    incomplete_comm_pattern_.clear();
+    const unsigned long maxpid = api::get().get_maxpid();
+    for (unsigned long i = 0; i < maxpid; i++) {
+      std::vector<simgrid::mc::PatternCommunication> res;
+      for (auto const& comm : checker_->incomplete_communications_pattern[i])
+        res.push_back(comm->dup());
+      incomplete_comm_pattern_.push_back(std::move(res));
+    }
+  }
 
-/********** Static functions ***********/
+  void copy_index_comm_pattern()
+  {
+    communication_indices_.clear();
+    for (auto const& list_process_comm : checker_->initial_communications_pattern)
+      this->communication_indices_.push_back(list_process_comm.index_comm);
+  }
+};
+simgrid::xbt::Extension<simgrid::mc::State, StateCommDet> StateCommDet::EXTENSION_ID;
 
-static e_mc_comm_pattern_difference_t compare_comm_pattern(simgrid::mc::PatternCommunication* comm1,
-                                                           simgrid::mc::PatternCommunication* comm2)
+static simgrid::mc::CommPatternDifference compare_comm_pattern(const simgrid::mc::PatternCommunication* comm1,
+                                                               const simgrid::mc::PatternCommunication* comm2)
 {
-  if(comm1->type != comm2->type)
-    return TYPE_DIFF;
-  if (comm1->rdv != comm2->rdv)
-    return RDV_DIFF;
+  using simgrid::mc::CommPatternDifference;
+  if (comm1->type != comm2->type)
+    return CommPatternDifference::TYPE;
+  if (comm1->mbox != comm2->mbox)
+    return CommPatternDifference::MBOX;
   if (comm1->src_proc != comm2->src_proc)
-    return SRC_PROC_DIFF;
+    return CommPatternDifference::SRC_PROC;
   if (comm1->dst_proc != comm2->dst_proc)
-    return DST_PROC_DIFF;
+    return CommPatternDifference::DST_PROC;
   if (comm1->tag != comm2->tag)
-    return TAG_DIFF;
-  if (comm1->data.size() != comm2->data.size())
-    return DATA_SIZE_DIFF;
-  if (comm1->data != comm2->data)
-    return DATA_DIFF;
-  return NONE_DIFF;
+    return CommPatternDifference::TAG;
+  if (comm1->size != comm2->size)
+    return CommPatternDifference::DATA_SIZE;
+  return CommPatternDifference::NONE;
 }
 
-static char* print_determinism_result(e_mc_comm_pattern_difference_t diff, int process,
-                                      simgrid::mc::PatternCommunication* comm, unsigned int cursor)
+void CommDetExtension::restore_communications_pattern(const simgrid::mc::State* state)
 {
-  char* type;
-  char* res;
+  for (size_t i = 0; i < initial_communications_pattern.size(); i++)
+    initial_communications_pattern[i].index_comm =
+        state->extension<simgrid::mc::StateCommDet>()->communication_indices_[i];
+
+  const unsigned long maxpid = api::get().get_maxpid();
+  for (unsigned long i = 0; i < maxpid; i++) {
+    incomplete_communications_pattern[i].clear();
+    for (simgrid::mc::PatternCommunication const& comm :
+         state->extension<simgrid::mc::StateCommDet>()->incomplete_comm_pattern_[i])
+      incomplete_communications_pattern[i].push_back(new simgrid::mc::PatternCommunication(comm.dup()));
+  }
+}
+
+static std::string print_determinism_result(simgrid::mc::CommPatternDifference diff, aid_t process,
+                                            const simgrid::mc::PatternCommunication* comm, unsigned int cursor)
+{
+  std::string type;
+  std::string res;
 
   if (comm->type == simgrid::mc::PatternCommunicationType::send)
-    type = bprintf("The send communications pattern of the process %d is different!", process - 1);
+    type = xbt::string_printf("The send communications pattern of the process %ld is different!", process - 1);
   else
-    type = bprintf("The recv communications pattern of the process %d is different!", process - 1);
-
-  switch(diff) {
-  case TYPE_DIFF:
-    res = bprintf("%s Different type for communication #%u", type, cursor);
-    break;
-  case RDV_DIFF:
-    res = bprintf("%s Different rdv for communication #%u", type, cursor);
-    break;
-  case TAG_DIFF:
-    res = bprintf("%s Different tag for communication #%u", type, cursor);
-    break;
-  case SRC_PROC_DIFF:
-    res = bprintf("%s Different source for communication #%u", type, cursor);
-    break;
-  case DST_PROC_DIFF:
-    res = bprintf("%s Different destination for communication #%u", type, cursor);
-    break;
-  case DATA_SIZE_DIFF:
-    res = bprintf("%s\n Different data size for communication #%u", type, cursor);
-    break;
-  case DATA_DIFF:
-    res = bprintf("%s\n Different data for communication #%u", type, cursor);
-    break;
-  default:
-    res = nullptr;
-    break;
+    type = xbt::string_printf("The recv communications pattern of the process %ld is different!", process - 1);
+
+  using simgrid::mc::CommPatternDifference;
+  switch (diff) {
+    case CommPatternDifference::TYPE:
+      res = xbt::string_printf("%s Different type for communication #%u", type.c_str(), cursor);
+      break;
+    case CommPatternDifference::MBOX:
+      res = xbt::string_printf("%s Different mailbox for communication #%u", type.c_str(), cursor);
+      break;
+    case CommPatternDifference::TAG:
+      res = xbt::string_printf("%s Different tag for communication #%u", type.c_str(), cursor);
+      break;
+    case CommPatternDifference::SRC_PROC:
+      res = xbt::string_printf("%s Different source for communication #%u", type.c_str(), cursor);
+      break;
+    case CommPatternDifference::DST_PROC:
+      res = xbt::string_printf("%s Different destination for communication #%u", type.c_str(), cursor);
+      break;
+    case CommPatternDifference::DATA_SIZE:
+      res = xbt::string_printf("%s Different data size for communication #%u", type.c_str(), cursor);
+      break;
+    default:
+      res = "";
+      break;
   }
 
   return res;
 }
 
-static void update_comm_pattern(simgrid::mc::PatternCommunication* comm_pattern,
-                                simgrid::mc::RemotePtr<simgrid::kernel::activity::CommImpl> comm_addr)
+void CommDetExtension::deterministic_comm_pattern(aid_t actor, const PatternCommunication* comm, bool backtracking)
 {
-  // HACK, type punning
-  simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
-  mc_model_checker->process().read(temp_comm, comm_addr);
-  simgrid::kernel::activity::CommImpl* comm = temp_comm.getBuffer();
-
-  smx_actor_t src_proc   = mc_model_checker->process().resolveActor(simgrid::mc::remote(comm->src_actor_.get()));
-  smx_actor_t dst_proc   = mc_model_checker->process().resolveActor(simgrid::mc::remote(comm->dst_actor_.get()));
-  comm_pattern->src_proc = src_proc->pid_;
-  comm_pattern->dst_proc = dst_proc->pid_;
-  comm_pattern->src_host = MC_smx_actor_get_host_name(src_proc);
-  comm_pattern->dst_host = MC_smx_actor_get_host_name(dst_proc);
-  if (comm_pattern->data.size() == 0 && comm->src_buff_ != nullptr) {
-    size_t buff_size;
-    mc_model_checker->process().read(&buff_size, remote(comm->dst_buff_size_));
-    comm_pattern->data.resize(buff_size);
-    mc_model_checker->process().read_bytes(comm_pattern->data.data(), comm_pattern->data.size(),
-                                           remote(comm->src_buff_));
-  }
-}
-
-namespace simgrid {
-namespace mc {
-
-void CommunicationDeterminismChecker::deterministic_comm_pattern(int process, simgrid::mc::PatternCommunication* comm,
-                                                                 int backtracking)
-{
-  simgrid::mc::PatternCommunicationList* list =
-    xbt_dynar_get_as(initial_communications_pattern, process, simgrid::mc::PatternCommunicationList*);
-
   if (not backtracking) {
-    e_mc_comm_pattern_difference_t diff = compare_comm_pattern(list->list[list->index_comm].get(), comm);
-
-    if (diff != NONE_DIFF) {
-      if (comm->type == simgrid::mc::PatternCommunicationType::send) {
-        this->send_deterministic = 0;
-        if (this->send_diff != nullptr)
-          xbt_free(this->send_diff);
-        this->send_diff = print_determinism_result(diff, process, comm, list->index_comm + 1);
+    PatternCommunicationList& list = initial_communications_pattern[actor];
+    CommPatternDifference diff     = compare_comm_pattern(list.list[list.index_comm].get(), comm);
+
+    if (diff != CommPatternDifference::NONE) {
+      if (comm->type == PatternCommunicationType::send) {
+        send_deterministic = false;
+        send_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
       } else {
-        this->recv_deterministic = 0;
-        if (this->recv_diff != nullptr)
-          xbt_free(this->recv_diff);
-        this->recv_diff = print_determinism_result(diff, process, comm, list->index_comm + 1);
+        recv_deterministic = false;
+        recv_diff          = print_determinism_result(diff, actor, comm, list.index_comm + 1);
       }
-      if (_sg_mc_send_determinism && not this->send_deterministic) {
+      if (_sg_mc_send_determinism && not send_deterministic) {
         XBT_INFO("*********************************************************");
         XBT_INFO("***** Non-send-deterministic communications pattern *****");
         XBT_INFO("*********************************************************");
-        XBT_INFO("%s", this->send_diff);
-        xbt_free(this->send_diff);
-        this->send_diff = nullptr;
-        simgrid::mc::session->logState();
-        mc_model_checker->exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
-      } else if (_sg_mc_comms_determinism && (not this->send_deterministic && not this->recv_deterministic)) {
+        XBT_INFO("%s", send_diff.c_str());
+        api::get().log_state();
+        api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
+      } else if (_sg_mc_comms_determinism && (not send_deterministic && not recv_deterministic)) {
         XBT_INFO("****************************************************");
         XBT_INFO("***** Non-deterministic communications pattern *****");
         XBT_INFO("****************************************************");
-        XBT_INFO("%s", this->send_diff);
-        XBT_INFO("%s", this->recv_diff);
-        xbt_free(this->send_diff);
-        this->send_diff = nullptr;
-        xbt_free(this->recv_diff);
-        this->recv_diff = nullptr;
-        simgrid::mc::session->logState();
-        mc_model_checker->exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
+        if (not send_diff.empty())
+          XBT_INFO("%s", send_diff.c_str());
+        if (not recv_diff.empty())
+          XBT_INFO("%s", recv_diff.c_str());
+        api::get().log_state();
+        api::get().mc_exit(SIMGRID_MC_EXIT_NON_DETERMINISM);
       }
     }
   }
@@ -167,239 +238,173 @@ void CommunicationDeterminismChecker::deterministic_comm_pattern(int process, si
 
 /********** Non Static functions ***********/
 
-void CommunicationDeterminismChecker::get_comm_pattern(xbt_dynar_t list, smx_simcall_t request,
-                                                       e_mc_call_type_t call_type, int backtracking)
+void CommDetExtension::get_comm_pattern(const Transition* transition, bool backtracking)
 {
-  const smx_actor_t issuer = MC_smx_simcall_get_issuer(request);
-  simgrid::mc::PatternCommunicationList* initial_pattern =
-      xbt_dynar_get_as(initial_communications_pattern, issuer->pid_, simgrid::mc::PatternCommunicationList*);
-  xbt_dynar_t incomplete_pattern = xbt_dynar_get_as(incomplete_communications_pattern, issuer->pid_, xbt_dynar_t);
+  const mc::PatternCommunicationList& initial_pattern          = initial_communications_pattern[transition->aid_];
+  const std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[transition->aid_];
 
-  std::unique_ptr<simgrid::mc::PatternCommunication> pattern =
-      std::unique_ptr<simgrid::mc::PatternCommunication>(new simgrid::mc::PatternCommunication());
-  pattern->index = initial_pattern->index_comm + xbt_dynar_length(incomplete_pattern);
+  auto pattern   = std::make_unique<PatternCommunication>();
+  pattern->index = initial_pattern.index_comm + incomplete_pattern.size();
 
-  if (call_type == MC_CALL_TYPE_SEND) {
+  if (transition->type_ == Transition::Type::COMM_SEND) {
+    auto* send = dynamic_cast<const CommSendTransition*>(transition);
     /* Create comm pattern */
-    pattern->type = simgrid::mc::PatternCommunicationType::send;
-    pattern->comm_addr = static_cast<simgrid::kernel::activity::CommImpl*>(simcall_comm_isend__getraw__result(request));
-
-    simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_synchro;
-    mc_model_checker->process().read(temp_synchro,
-                                     remote(static_cast<simgrid::kernel::activity::CommImpl*>(pattern->comm_addr)));
-    simgrid::kernel::activity::CommImpl* synchro =
-        static_cast<simgrid::kernel::activity::CommImpl*>(temp_synchro.getBuffer());
-
-    char* remote_name = mc_model_checker->process().read<char*>(
-        RemotePtr<char*>((uint64_t)(synchro->mbox ? &synchro->mbox->name_ : &synchro->mbox_cpy->name_)));
-    pattern->rdv      = mc_model_checker->process().read_string(RemotePtr<char>(remote_name));
-    pattern->src_proc = mc_model_checker->process().resolveActor(simgrid::mc::remote(synchro->src_actor_.get()))->pid_;
-    pattern->src_host = MC_smx_actor_get_host_name(issuer);
+    pattern->type      = PatternCommunicationType::send;
+    pattern->comm_addr = send->get_comm();
+    pattern->mbox      = send->get_mailbox();
+    pattern->src_proc  = send->aid_;
 
 #if HAVE_SMPI
-    simgrid::smpi::Request mpi_request = mc_model_checker->process().read<simgrid::smpi::Request>(
-        RemotePtr<simgrid::smpi::Request>((std::uint64_t)simcall_comm_isend__get__data(request)));
-    pattern->tag = mpi_request.tag();
+    pattern->tag = 0; // FIXME: replace it by the real tag from the observer
 #endif
 
-    if (synchro->src_buff_ != nullptr) {
-      pattern->data.resize(synchro->src_buff_size_);
-      mc_model_checker->process().read_bytes(pattern->data.data(), pattern->data.size(), remote(synchro->src_buff_));
-    }
 #if HAVE_SMPI
-    if(mpi_request.detached()){
-      if (not this->initial_communications_pattern_done) {
-        /* Store comm pattern */
-        simgrid::mc::PatternCommunicationList* list =
-            xbt_dynar_get_as(initial_communications_pattern, pattern->src_proc, simgrid::mc::PatternCommunicationList*);
-        list->list.push_back(std::move(pattern));
-      } else {
+    // auto send_detached = api::get().check_send_request_detached(request);
+    if (false) { // send_detached) {
+      if (initial_communications_pattern_done) {
         /* Evaluate comm determinism */
-        this->deterministic_comm_pattern(pattern->src_proc, pattern.get(), backtracking);
-        xbt_dynar_get_as(initial_communications_pattern, pattern->src_proc, simgrid::mc::PatternCommunicationList*)
-            ->index_comm++;
+        deterministic_comm_pattern(pattern->src_proc, pattern.get(), backtracking);
+        initial_communications_pattern[pattern->src_proc].index_comm++;
+      } else {
+        /* Store comm pattern */
+        initial_communications_pattern[pattern->src_proc].list.push_back(std::move(pattern));
       }
       return;
     }
 #endif
-  } else if (call_type == MC_CALL_TYPE_RECV) {
-    pattern->type = simgrid::mc::PatternCommunicationType::receive;
-    pattern->comm_addr = static_cast<simgrid::kernel::activity::CommImpl*>(simcall_comm_irecv__getraw__result(request));
+  } else if (transition->type_ == Transition::Type::COMM_RECV) {
+    auto* recv = static_cast<const CommRecvTransition*>(transition);
+
+    pattern->type = PatternCommunicationType::receive;
+    pattern->comm_addr = recv->get_comm();
 
 #if HAVE_SMPI
-    simgrid::smpi::Request mpi_request;
-    mc_model_checker->process().read(&mpi_request,
-                                     remote((simgrid::smpi::Request*)simcall_comm_irecv__get__data(request)));
-    pattern->tag = mpi_request.tag();
+    pattern->tag = 0; // FIXME: replace it by the real tag from the observer
 #endif
+    pattern->mbox     = recv->get_mailbox();
+    pattern->dst_proc = recv->aid_;
+  }
 
-    simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
-    mc_model_checker->process().read(temp_comm,
-                                     remote(static_cast<simgrid::kernel::activity::CommImpl*>(pattern->comm_addr)));
-    simgrid::kernel::activity::CommImpl* comm = temp_comm.getBuffer();
-
-    char* remote_name;
-    mc_model_checker->process().read(
-        &remote_name, remote(comm->mbox ? &simgrid::xbt::string::to_string_data(comm->mbox->name_).data
-                                        : &simgrid::xbt::string::to_string_data(comm->mbox_cpy->name_).data));
-    pattern->rdv      = mc_model_checker->process().read_string(RemotePtr<char>(remote_name));
-    pattern->dst_proc = mc_model_checker->process().resolveActor(simgrid::mc::remote(comm->dst_actor_.get()))->pid_;
-    pattern->dst_host = MC_smx_actor_get_host_name(issuer);
-  } else
-    xbt_die("Unexpected call_type %i", (int) call_type);
-
-  XBT_DEBUG("Insert incomplete comm pattern %p for process %ld", pattern.get(), issuer->pid_);
-  xbt_dynar_t dynar = xbt_dynar_get_as(incomplete_communications_pattern, issuer->pid_, xbt_dynar_t);
-  simgrid::mc::PatternCommunication* pattern2 = pattern.release();
-  xbt_dynar_push(dynar, &pattern2);
+  XBT_DEBUG("Insert incomplete comm pattern %p type:%d for process %ld (comm: %lx)", pattern.get(), (int)pattern->type,
+            transition->aid_, pattern->comm_addr);
+  incomplete_communications_pattern[transition->aid_].push_back(pattern.release());
 }
 
-void CommunicationDeterminismChecker::complete_comm_pattern(
-    xbt_dynar_t list, simgrid::mc::RemotePtr<simgrid::kernel::activity::CommImpl> comm_addr, unsigned int issuer,
-    int backtracking)
+void CommDetExtension::complete_comm_pattern(const CommWaitTransition* transition, bool backtracking)
 {
-  simgrid::mc::PatternCommunication* current_comm_pattern;
-  unsigned int cursor = 0;
-  std::unique_ptr<simgrid::mc::PatternCommunication> comm_pattern;
-  int completed = 0;
-
   /* Complete comm pattern */
-  xbt_dynar_foreach(xbt_dynar_get_as(incomplete_communications_pattern, issuer, xbt_dynar_t), cursor, current_comm_pattern)
-    if (remote(current_comm_pattern->comm_addr) == comm_addr) {
-      update_comm_pattern(current_comm_pattern, comm_addr);
-      completed = 1;
-      simgrid::mc::PatternCommunication* temp;
-      xbt_dynar_remove_at(xbt_dynar_get_as(incomplete_communications_pattern, issuer, xbt_dynar_t), cursor, &temp);
-      comm_pattern = std::unique_ptr<simgrid::mc::PatternCommunication>(temp);
-      XBT_DEBUG("Remove incomplete comm pattern for process %u at cursor %u", issuer, cursor);
-      break;
-    }
-
-  if (not completed)
-    xbt_die("Corresponding communication not found!");
-
-  simgrid::mc::PatternCommunicationList* pattern =
-      xbt_dynar_get_as(initial_communications_pattern, issuer, simgrid::mc::PatternCommunicationList*);
-
-  if (not this->initial_communications_pattern_done)
-    /* Store comm pattern */
-    pattern->list.push_back(std::move(comm_pattern));
-  else {
+  std::vector<PatternCommunication*>& incomplete_pattern = incomplete_communications_pattern[transition->aid_];
+  uintptr_t comm_addr                                    = transition->get_comm();
+  auto current_comm_pattern =
+      std::find_if(begin(incomplete_pattern), end(incomplete_pattern),
+                   [&comm_addr](const PatternCommunication* comm) { return (comm->comm_addr == comm_addr); });
+  xbt_assert(current_comm_pattern != std::end(incomplete_pattern), "Corresponding communication not found!");
+  std::unique_ptr<PatternCommunication> comm_pattern(*current_comm_pattern);
+
+  comm_pattern->src_proc = transition->get_sender();
+  comm_pattern->dst_proc = transition->get_receiver();
+
+  XBT_DEBUG("Remove incomplete comm pattern for actor %ld at cursor %zd", transition->aid_,
+            std::distance(begin(incomplete_pattern), current_comm_pattern));
+  incomplete_pattern.erase(current_comm_pattern);
+
+  if (initial_communications_pattern_done) {
     /* Evaluate comm determinism */
-    this->deterministic_comm_pattern(issuer, comm_pattern.get(), backtracking);
-    pattern->index_comm++;
+    deterministic_comm_pattern(transition->aid_, comm_pattern.get(), backtracking);
+    initial_communications_pattern[transition->aid_].index_comm++;
+  } else {
+    /* Store comm pattern */
+    initial_communications_pattern[transition->aid_].list.push_back(std::move(comm_pattern));
   }
 }
 
-CommunicationDeterminismChecker::CommunicationDeterminismChecker(Session& session) : Checker(session)
+CommunicationDeterminismChecker::CommunicationDeterminismChecker(Session* session) : Checker(session)
 {
+  CommDetExtension::EXTENSION_ID = simgrid::mc::Checker::extension_create<CommDetExtension>();
+  StateCommDet::EXTENSION_ID = simgrid::mc::State::extension_create<StateCommDet>();
 }
 
 CommunicationDeterminismChecker::~CommunicationDeterminismChecker() = default;
 
-RecordTrace CommunicationDeterminismChecker::getRecordTrace() // override
+RecordTrace CommunicationDeterminismChecker::get_record_trace() // override
 {
   RecordTrace res;
   for (auto const& state : stack_)
-    res.push_back(state->getTransition());
+    res.push_back(state->get_transition());
   return res;
 }
 
-std::vector<std::string> CommunicationDeterminismChecker::getTextualTrace() // override
+std::vector<std::string> CommunicationDeterminismChecker::get_textual_trace() // override
 {
   std::vector<std::string> trace;
-  for (auto const& state : stack_) {
-    smx_simcall_t req = &state->executed_req;
-    if (req)
-      trace.push_back(
-          simgrid::mc::request_to_string(req, state->transition.argument, simgrid::mc::RequestType::executed));
-  }
+  for (auto const& state : stack_)
+    trace.push_back(state->get_transition()->to_string());
   return trace;
 }
 
-void CommunicationDeterminismChecker::logState() // override
+void CommunicationDeterminismChecker::log_state() // override
 {
-  if (_sg_mc_comms_determinism && not this->recv_deterministic && this->send_deterministic) {
-    XBT_INFO("******************************************************");
-    XBT_INFO("**** Only-send-deterministic communication pattern ****");
-    XBT_INFO("******************************************************");
-    XBT_INFO("%s", this->recv_diff);
-  } else if (_sg_mc_comms_determinism && not this->send_deterministic && this->recv_deterministic) {
-    XBT_INFO("******************************************************");
-    XBT_INFO("**** Only-recv-deterministic communication pattern ****");
-    XBT_INFO("******************************************************");
-    XBT_INFO("%s", this->send_diff);
+  if (_sg_mc_comms_determinism) {
+    if (extension<CommDetExtension>()->send_deterministic && not extension<CommDetExtension>()->recv_deterministic) {
+      XBT_INFO("*******************************************************");
+      XBT_INFO("**** Only-send-deterministic communication pattern ****");
+      XBT_INFO("*******************************************************");
+      XBT_INFO("%s", extension<CommDetExtension>()->recv_diff.c_str());
+    }
+    if (not extension<CommDetExtension>()->send_deterministic && extension<CommDetExtension>()->recv_deterministic) {
+      XBT_INFO("*******************************************************");
+      XBT_INFO("**** Only-recv-deterministic communication pattern ****");
+      XBT_INFO("*******************************************************");
+      XBT_INFO("%s", extension<CommDetExtension>()->send_diff.c_str());
+    }
   }
-  XBT_INFO("Expanded states = %lu", expandedStatesCount_);
-  XBT_INFO("Visited states = %lu", mc_model_checker->visited_states);
-  XBT_INFO("Executed transitions = %lu", mc_model_checker->executed_transitions);
-  XBT_INFO("Send-deterministic : %s", not this->send_deterministic ? "No" : "Yes");
+  XBT_INFO("Expanded states = %ld", State::get_expanded_states());
+  XBT_INFO("Visited states = %lu", api::get().mc_get_visited_states());
+  XBT_INFO("Executed transitions = %lu", Transition::get_executed_transitions());
+  XBT_INFO("Send-deterministic : %s", extension<CommDetExtension>()->send_deterministic ? "Yes" : "No");
   if (_sg_mc_comms_determinism)
-    XBT_INFO("Recv-deterministic : %s", not this->recv_deterministic ? "No" : "Yes");
+    XBT_INFO("Recv-deterministic : %s", extension<CommDetExtension>()->recv_deterministic ? "Yes" : "No");
 }
 
 void CommunicationDeterminismChecker::prepare()
 {
-  const int maxpid = MC_smx_get_maxpid();
-
-  // Create initial_communications_pattern elements:
-  initial_communications_pattern = simgrid::xbt::newDeleteDynar<simgrid::mc::PatternCommunicationList*>();
-  for (int i = 0; i < maxpid; i++) {
-    simgrid::mc::PatternCommunicationList* process_list_pattern = new simgrid::mc::PatternCommunicationList();
-    xbt_dynar_insert_at(initial_communications_pattern, i, &process_list_pattern);
-  }
-
-  // Create incomplete_communications_pattern elements:
-  incomplete_communications_pattern = xbt_dynar_new(sizeof(xbt_dynar_t), xbt_dynar_free_voidp);
-  for (int i = 0; i < maxpid; i++) {
-    xbt_dynar_t process_pattern = xbt_dynar_new(sizeof(simgrid::mc::PatternCommunication*), nullptr);
-    xbt_dynar_insert_at(incomplete_communications_pattern, i, &process_pattern);
-  }
-
-  std::unique_ptr<simgrid::mc::State> initial_state =
-      std::unique_ptr<simgrid::mc::State>(new simgrid::mc::State(++expandedStatesCount_));
+  auto initial_state = std::make_unique<State>();
+  extension_set(new CommDetExtension());
+  initial_state->extension_set(new StateCommDet(extension<CommDetExtension>()));
 
   XBT_DEBUG("********* Start communication determinism verification *********");
 
-  /* Get an enabled actor and insert it in the interleave set of the initial state */
-  for (auto& actor : mc_model_checker->process().actors())
-    if (simgrid::mc::actor_is_enabled(actor.copy.getBuffer()))
-      initial_state->addInterleavingSet(actor.copy.getBuffer());
+  /* Add all enabled actors to the interleave set of the initial state */
+  for (auto& act : api::get().get_actors()) {
+    auto actor = act.copy.get_buffer();
+    if (get_session().actor_is_enabled(actor->get_pid()))
+      initial_state->mark_todo(actor->get_pid());
+  }
 
   stack_.push_back(std::move(initial_state));
 }
 
-static inline bool all_communications_are_finished()
-{
-  for (size_t current_actor = 1; current_actor < MC_smx_get_maxpid(); current_actor++) {
-    xbt_dynar_t pattern = xbt_dynar_get_as(incomplete_communications_pattern, current_actor, xbt_dynar_t);
-    if (not xbt_dynar_is_empty(pattern)) {
-      XBT_DEBUG("Some communications are not finished, cannot stop the exploration! State not visited.");
-      return false;
-    }
-  }
-  return true;
-}
-
 void CommunicationDeterminismChecker::restoreState()
 {
-  /* Intermediate backtracking */
-  simgrid::mc::State* state = stack_.back().get();
-  if (state->system_state) {
-    simgrid::mc::restore_snapshot(state->system_state);
-    MC_restore_communications_pattern(state);
+  auto extension = this->extension<CommDetExtension>();
+
+  /* If asked to rollback on a state that has a snapshot, restore it */
+  State* last_state = stack_.back().get();
+  if (last_state->system_state_) {
+    api::get().restore_state(last_state->system_state_);
+    extension->restore_communications_pattern(last_state);
     return;
   }
 
-  /* Restore the initial state */
-  simgrid::mc::session->restoreInitialState();
+  /* if no snapshot, we need to restore the initial state and replay the transitions */
+  get_session().restore_initial_state();
 
-  unsigned n = MC_smx_get_maxpid();
-  assert(n == xbt_dynar_length(incomplete_communications_pattern));
-  assert(n == xbt_dynar_length(initial_communications_pattern));
-  for (unsigned j=0; j < n ; j++) {
-    xbt_dynar_reset((xbt_dynar_t)xbt_dynar_get_as(incomplete_communications_pattern, j, xbt_dynar_t));
-    xbt_dynar_get_as(initial_communications_pattern, j, simgrid::mc::PatternCommunicationList*)->index_comm = 0;
+  const unsigned long maxpid = api::get().get_maxpid();
+  assert(maxpid == extension->incomplete_communications_pattern.size());
+  assert(maxpid == extension->initial_communications_pattern.size());
+  for (unsigned long j = 0; j < maxpid; j++) {
+    extension->incomplete_communications_pattern[j].clear();
+    extension->initial_communications_pattern[j].index_comm = 0;
   }
 
   /* Traverse the stack from the state at position start and re-execute the transitions */
@@ -407,171 +412,169 @@ void CommunicationDeterminismChecker::restoreState()
     if (state == stack_.back())
       break;
 
-    int req_num = state->transition.argument;
-    smx_simcall_t saved_req = &state->executed_req;
-    xbt_assert(saved_req);
-
-    /* because we got a copy of the executed request, we have to fetch the
-       real one, pointed by the request field of the issuer process */
+    auto* transition = state->get_transition();
+    transition->replay();
+    extension->handle_comm_pattern(transition, true);
 
-    const smx_actor_t issuer = MC_smx_simcall_get_issuer(saved_req);
-    smx_simcall_t req = &issuer->simcall;
+    /* Update statistics */
+    api::get().mc_inc_visited_states();
+  }
+}
 
-    /* TODO : handle test and testany simcalls */
-    e_mc_call_type_t call = MC_get_call_type(req);
-    mc_model_checker->handle_simcall(state->transition);
-    MC_handle_comm_pattern(call, req, req_num, nullptr, 1);
-    mc_model_checker->wait_for_requests();
+void CommDetExtension::handle_comm_pattern(const Transition* transition, bool backtracking)
+{
+  if (not _sg_mc_comms_determinism && not _sg_mc_send_determinism)
+    return;
 
-    /* Update statistics */
-    mc_model_checker->visited_states++;
-    mc_model_checker->executed_transitions++;
+  switch (transition->type_) {
+    case Transition::Type::COMM_SEND:
+      get_comm_pattern(transition, backtracking);
+      break;
+    case Transition::Type::COMM_RECV:
+      get_comm_pattern(transition, backtracking);
+      break;
+    case Transition::Type::COMM_WAIT: {
+      complete_comm_pattern(static_cast<const CommWaitTransition*>(transition), backtracking);
+      break;
+    }
+    case Transition::Type::WAITANY: {
+      auto const* t    = static_cast<const WaitAnyTransition*>(transition)->get_current_transition();
+      auto const* wait = dynamic_cast<const CommWaitTransition*>(t);
+      if (wait != nullptr) // Ignore wait on non-comm
+        complete_comm_pattern(wait, backtracking);
+    } break;
+    default: /* Ignore unhandled transition types */
+      break;
   }
 }
 
 void CommunicationDeterminismChecker::real_run()
 {
-  std::unique_ptr<simgrid::mc::VisitedState> visited_state = nullptr;
-  smx_simcall_t req = nullptr;
+  auto extension = this->extension<CommDetExtension>();
+
+  std::unique_ptr<VisitedState> visited_state = nullptr;
+  const unsigned long maxpid                  = api::get().get_maxpid();
 
   while (not stack_.empty()) {
     /* Get current state */
-    simgrid::mc::State* state = stack_.back().get();
+    State* cur_state = stack_.back().get();
 
     XBT_DEBUG("**************************************************");
-    XBT_DEBUG("Exploration depth = %zu (state = %d, interleaved processes = %zu)", stack_.size(), state->num,
-              state->interleaveSize());
+    XBT_DEBUG("Exploration depth = %zu (state = %ld, interleaved processes = %zu)", stack_.size(), cur_state->num_,
+              cur_state->count_todo());
 
     /* Update statistics */
-    mc_model_checker->visited_states++;
+    api::get().mc_inc_visited_states();
 
+    int next_transition = -1;
     if (stack_.size() <= (std::size_t)_sg_mc_max_depth)
-      req = MC_state_get_request(state);
-    else
-      req = nullptr;
-
-    if (req != nullptr && visited_state == nullptr) {
+      next_transition = cur_state->next_transition();
 
-      int req_num = state->transition.argument;
+    if (next_transition >= 0 && visited_state == nullptr) {
+      cur_state->execute_next(next_transition);
 
-      XBT_DEBUG("Execute: %s", simgrid::mc::request_to_string(req, req_num, simgrid::mc::RequestType::simix).c_str());
+      auto* transition  = cur_state->get_transition();
+      XBT_DEBUG("Execute: %s", transition->to_string().c_str());
 
       std::string req_str;
       if (dot_output != nullptr)
-        req_str = simgrid::mc::request_get_dot_output(req, req_num);
+        req_str = api::get().request_get_dot_output(transition);
 
-      mc_model_checker->executed_transitions++;
-
-      /* TODO : handle test and testany simcalls */
-      e_mc_call_type_t call = MC_CALL_TYPE_NONE;
-      if (_sg_mc_comms_determinism || _sg_mc_send_determinism)
-        call = MC_get_call_type(req);
-
-      /* Answer the request */
-      mc_model_checker->handle_simcall(state->transition);
-      /* After this call req is no longer useful */
-
-      if (not this->initial_communications_pattern_done)
-        MC_handle_comm_pattern(call, req, req_num, initial_communications_pattern, 0);
-      else
-        MC_handle_comm_pattern(call, req, req_num, nullptr, 0);
-
-      /* Wait for requests (schedules processes) */
-      mc_model_checker->wait_for_requests();
+      extension->handle_comm_pattern(transition, false);
 
       /* Create the new expanded state */
-      std::unique_ptr<simgrid::mc::State> next_state =
-          std::unique_ptr<simgrid::mc::State>(new simgrid::mc::State(++expandedStatesCount_));
+      auto next_state = std::make_unique<State>();
+      next_state->extension_set(new StateCommDet(extension));
+
+      bool all_communications_are_finished = true;
+      for (size_t current_actor = 1; all_communications_are_finished && current_actor < maxpid; current_actor++) {
+        if (not extension->incomplete_communications_pattern[current_actor].empty()) {
+          XBT_DEBUG("Some communications are not finished, cannot stop the exploration! State not visited.");
+          all_communications_are_finished = false;
+        }
+      }
 
       /* If comm determinism verification, we cannot stop the exploration if some communications are not finished (at
        * least, data are transferred). These communications  are incomplete and they cannot be analyzed and compared
        * with the initial pattern. */
-      bool compare_snapshots = all_communications_are_finished() && this->initial_communications_pattern_done;
+      bool compare_snapshots = extension->initial_communications_pattern_done && all_communications_are_finished;
 
       if (_sg_mc_max_visited_states != 0)
-        visited_state = visitedStates_.addVisitedState(expandedStatesCount_, next_state.get(), compare_snapshots);
+        visited_state = visited_states_.addVisitedState(next_state->num_, next_state.get(), compare_snapshots);
       else
         visited_state = nullptr;
 
       if (visited_state == nullptr) {
-
-        /* Get enabled actors and insert them in the interleave set of the next state */
-        for (auto& actor : mc_model_checker->process().actors())
-          if (simgrid::mc::actor_is_enabled(actor.copy.getBuffer()))
-            next_state->addInterleavingSet(actor.copy.getBuffer());
+        /* Add all enabled actors to the interleave set of the next state */
+        for (auto& act : api::get().get_actors()) {
+          auto actor = act.copy.get_buffer();
+          if (get_session().actor_is_enabled(actor->get_pid()))
+            next_state->mark_todo(actor->get_pid());
+        }
 
         if (dot_output != nullptr)
-          fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n",
-            state->num,  next_state->num, req_str.c_str());
+          fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_, next_state->num_, req_str.c_str());
 
       } else if (dot_output != nullptr)
-        fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", state->num,
+        fprintf(dot_output, "\"%ld\" -> \"%ld\" [%s];\n", cur_state->num_,
                 visited_state->original_num == -1 ? visited_state->num : visited_state->original_num, req_str.c_str());
 
       stack_.push_back(std::move(next_state));
-
     } else {
-
-      if (stack_.size() > (std::size_t) _sg_mc_max_depth)
+      if (stack_.size() > (std::size_t)_sg_mc_max_depth)
         XBT_WARN("/!\\ Max depth reached! /!\\ ");
       else if (visited_state != nullptr)
-        XBT_DEBUG("State already visited (equal to state %d), exploration stopped on this path.",
-            visited_state->original_num == -1 ? visited_state->num : visited_state->original_num);
+        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);
       else
         XBT_DEBUG("There are no more processes to interleave. (depth %zu)", stack_.size());
 
-      if (not this->initial_communications_pattern_done)
-        this->initial_communications_pattern_done = 1;
+      extension->initial_communications_pattern_done = true;
 
       /* Trash the current state, no longer needed */
-      XBT_DEBUG("Delete state %d at depth %zu", state->num, stack_.size());
+      XBT_DEBUG("Delete state %ld at depth %zu", cur_state->num_, stack_.size());
       stack_.pop_back();
 
       visited_state = nullptr;
 
-      /* Check for deadlocks */
-      if (mc_model_checker->checkDeadlock()) {
-        MC_show_deadlock();
-        throw simgrid::mc::DeadlockError();
-      }
+      api::get().mc_check_deadlock();
 
       while (not stack_.empty()) {
-        std::unique_ptr<simgrid::mc::State> state = std::move(stack_.back());
+        std::unique_ptr<State> state(std::move(stack_.back()));
         stack_.pop_back();
-        if (state->interleaveSize() && stack_.size() < (std::size_t)_sg_mc_max_depth) {
+        if (state->count_todo() && stack_.size() < (std::size_t)_sg_mc_max_depth) {
           /* We found a back-tracking point, let's loop */
-          XBT_DEBUG("Back-tracking to state %d at depth %zu", state->num, stack_.size() + 1);
+          XBT_DEBUG("Back-tracking to state %ld at depth %zu", state->num_, stack_.size() + 1);
           stack_.push_back(std::move(state));
 
           this->restoreState();
 
-          XBT_DEBUG("Back-tracking to state %d at depth %zu done", stack_.back()->num, stack_.size());
+          XBT_DEBUG("Back-tracking to state %ld at depth %zu done", stack_.back()->num_, stack_.size());
 
           break;
         } else {
-          XBT_DEBUG("Delete state %d at depth %zu", state->num, stack_.size() + 1);
+          XBT_DEBUG("Delete state %ld at depth %zu", state->num_, stack_.size() + 1);
         }
       }
     }
   }
 
-  simgrid::mc::session->logState();
+  api::get().log_state();
 }
 
 void CommunicationDeterminismChecker::run()
 {
   XBT_INFO("Check communication determinism");
-  simgrid::mc::session->initialize();
+  get_session().take_initial_snapshot();
 
   this->prepare();
-
   this->real_run();
 }
 
-Checker* createCommunicationDeterminismChecker(Session& session)
+Checker* create_communication_determinism_checker(Session* session)
 {
   return new CommunicationDeterminismChecker(session);
 }
 
-}
-}
+} // namespace mc
+} // namespace simgrid