X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/12e01354e36033d37625d9675769d18058f7c1e7..dd7150adabf3473303e6564c703941dc6239c8b1:/src/mc/mc_base.cpp

diff --git a/src/mc/mc_base.cpp b/src/mc/mc_base.cpp
index 384501de4d..e567c57397 100644
--- a/src/mc/mc_base.cpp
+++ b/src/mc/mc_base.cpp
@@ -56,6 +56,142 @@ void wait_for_requests()
 #endif
 }
 
+/** @brief returns if there this transition can proceed in a finite amount of time
+ *
+ * It is used in the model-checker to not get into self-deadlock where it would execute a never ending transition.
+ *
+ * Only WAIT operations (on comm, on mutex, etc) can ever return false because they could lock the MC exploration.
+ * Wait operations are OK and return true in only two situations:
+ *  - if the wait will succeed immediately (if both peer of the comm are there already or if the mutex is available)
+ *  - if a timeout is provided, because we can fire the timeout if the transition is not ready without blocking in this
+ * transition for ever.
+ *
+ */
+// Called from both MCer and MCed:
+bool actor_is_enabled(smx_actor_t actor)
+{
+  smx_simcall_t req = &actor->simcall;
+  // TODO, add support for the subtypes?
+
+  switch (req->call) {
+    case SIMCALL_NONE:
+      return false;
+
+    case SIMCALL_COMM_WAIT: {
+      /* FIXME: check also that src and dst processes are not suspended */
+      simgrid::kernel::activity::CommImpl* act =
+          static_cast<simgrid::kernel::activity::CommImpl*>(simcall_comm_wait__getraw__comm(req));
+
+#if SIMGRID_HAVE_MC
+      // Fetch from MCed memory:
+      // HACK, type puning
+      if (mc_model_checker != nullptr) {
+        simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
+        mc_model_checker->process().read(temp_comm, remote(act));
+        act = static_cast<simgrid::kernel::activity::CommImpl*>(temp_comm.getBuffer());
+      }
+#endif
+
+      if (act->src_timeout || act->dst_timeout) {
+        /* If it has a timeout it will be always be enabled (regardless of who declared the timeout),
+         * because even if the communication is not ready, it can timeout and won't block. */
+        if (_sg_mc_timeout == 1)
+          return true;
+      }
+      /* On the other hand if it hasn't a timeout, check if the comm is ready.*/
+      else if (act->detached && act->src_proc == nullptr && act->type == SIMIX_COMM_READY)
+        return (act->dst_proc != nullptr);
+      return (act->src_proc && act->dst_proc);
+    }
+
+    case SIMCALL_COMM_WAITANY: {
+      xbt_dynar_t comms;
+      simgrid::kernel::activity::CommImpl* act =
+          static_cast<simgrid::kernel::activity::CommImpl*>(simcall_comm_wait__getraw__comm(req));
+
+#if SIMGRID_HAVE_MC
+      s_xbt_dynar_t comms_buffer;
+      size_t buffer_size = 0;
+      if (mc_model_checker != nullptr) {
+        // Read dynar:
+        mc_model_checker->process().read(&comms_buffer, remote(simcall_comm_waitany__get__comms(req)));
+        assert(comms_buffer.elmsize == sizeof(act));
+        buffer_size = comms_buffer.elmsize * comms_buffer.used;
+        comms       = &comms_buffer;
+      } else
+        comms = simcall_comm_waitany__get__comms(req);
+
+      // Read all the dynar buffer:
+      char buffer[buffer_size];
+      if (mc_model_checker != nullptr)
+        mc_model_checker->process().read_bytes(buffer, sizeof(buffer), remote(comms->data));
+#else
+      comms = simcall_comm_waitany__get__comms(req);
+#endif
+
+      for (unsigned int index = 0; index < comms->used; ++index) {
+#if SIMGRID_HAVE_MC
+        // Fetch act from MCed memory:
+        // HACK, type puning
+        simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
+        if (mc_model_checker != nullptr) {
+          memcpy(&act, buffer + comms->elmsize * index, sizeof(act));
+          mc_model_checker->process().read(temp_comm, remote(act));
+          act = static_cast<simgrid::kernel::activity::CommImpl*>(temp_comm.getBuffer());
+        } else
+#endif
+          act = xbt_dynar_get_as(comms, index, simgrid::kernel::activity::CommImpl*);
+        if (act->src_proc && act->dst_proc)
+          return true;
+      }
+      return false;
+    }
+
+    case SIMCALL_MUTEX_LOCK: {
+      smx_mutex_t mutex = simcall_mutex_lock__get__mutex(req);
+#if SIMGRID_HAVE_MC
+      simgrid::mc::Remote<simgrid::simix::MutexImpl> temp_mutex;
+      if (mc_model_checker != nullptr) {
+        mc_model_checker->process().read(temp_mutex.getBuffer(), remote(mutex));
+        mutex = temp_mutex.getBuffer();
+      }
+#endif
+
+      if (mutex->owner == nullptr)
+        return true;
+#if SIMGRID_HAVE_MC
+      else if (mc_model_checker != nullptr) {
+        simgrid::mc::RemoteClient& modelchecked = mc_model_checker->process();
+        // TODO, *(mutex->owner) :/
+        return modelchecked.resolveActor(simgrid::mc::remote(mutex->owner))->pid ==
+               modelchecked.resolveActor(simgrid::mc::remote(req->issuer))->pid;
+      }
+#endif
+      else
+        return mutex->owner->pid == req->issuer->pid;
+    }
+
+    case SIMCALL_SEM_ACQUIRE: {
+      static int warned = 0;
+      if (not warned)
+        XBT_INFO("Using semaphore in model-checked code is still experimental. Use at your own risk");
+      warned = 1;
+      return true;
+    }
+
+    case SIMCALL_COND_WAIT: {
+      static int warned = 0;
+      if (not warned)
+        XBT_INFO("Using condition variables in model-checked code is still experimental. Use at your own risk");
+      warned = 1;
+      return true;
+    }
+
+    default:
+      /* The rest of the requests are always enabled */
+      return true;
+  }
+}
 
 bool request_is_visible(smx_simcall_t req)
 {