Merge remote-tracking branch 'origin/master'

diff --combined model.cc
index 73d212d0166d2ac3d2fc7368f25afac0333ac491,c9353db71c5bc15c77e802c32285f64f0c697681..39a7c2170f59fb0ac9b3a7d2160ecb80027283ff
--- 1/model.cc
--- 2/model.cc
+++ b/model.cc
@@@ -12,7 -12,6 +12,7 @@@
  #include "promise.h"
  #include "datarace.h"
  #include "mutex.h"
 +#include "threads.h"
  
  #define INITIAL_THREAD_ID     0
  
@@@ -100,12 -99,6 +100,12 @@@ int ModelChecker::get_num_threads(
        return priv->next_thread_id;
  }
  
 +/** @return The currently executing Thread. */
 +Thread * ModelChecker::get_current_thread()
 +{
 +      return scheduler->get_current_thread();
 +}
 +
  /** @return a sequence number for a new ModelAction */
  modelclock_t ModelChecker::get_next_seq_num()
  {
@@@ -941,7 -934,11 +941,11 @@@ bool ModelChecker::r_modification_order
                                        }
                                } else {
                                        const ModelAction *prevreadfrom = act->get_reads_from();
-                                       if (prevreadfrom != NULL && rf != prevreadfrom) {
+                                       //if the previous read is unresolved, keep going...
+                                       if (prevreadfrom == NULL)
+                                               continue;
+ 
+                                       if (rf != prevreadfrom) {
                                                mo_graph->addEdge(prevreadfrom, rf);
                                                added = true;
                                        }
@@@ -1066,14 -1063,22 +1070,22 @@@ bool ModelChecker::w_modification_order
                        ModelAction *act = *rit;
                        if (act == curr) {
                                /*
-                                * If RMW, we already have all relevant edges,
-                                * so just skip to next thread.
-                                * If normal write, we need to look at earlier
-                                * actions, so continue processing list.
+                                * 1) If RMW and it actually read from something, then we
+                                * already have all relevant edges, so just skip to next
+                                * thread.
+                                * 
+                                * 2) If RMW and it didn't read from anything, we should
+                                * whatever edge we can get to speed up convergence.
+                                *
+                                * 3) If normal write, we need to look at earlier actions, so
+                                * continue processing list.
                                 */
-                               if (curr->is_rmw())
-                                       break;
-                               else
+                               if (curr->is_rmw()) {
+                                       if (curr->get_reads_from()!=NULL)
+                                               break;
+                                       else 
+                                               continue;
+                               } else
                                        continue;
                        }
  
@@@ -1090,8 -1095,12 +1102,12 @@@
                                 */
                                if (act->is_write())
                                        mo_graph->addEdge(act, curr);
-                               else if (act->is_read() && act->get_reads_from() != NULL)
+                               else if (act->is_read()) { 
+                                       //if previous read accessed a null, just keep going
+                                       if (act->get_reads_from() == NULL)
+                                               continue;
                                        mo_graph->addEdge(act->get_reads_from(), curr);
+                               }
                                added = true;
                                break;
                        } else if (act->is_read() && !act->is_synchronizing(curr) &&
@@@ -1635,7 -1644,8 +1651,8 @@@ void ModelChecker::dumpGraph(char *file
                ModelAction *action=*it;
                if (action->is_read()) {
                        fprintf(file, "N%u [label=\"%u, T%u\"];\n", action->get_seq_number(),action->get_seq_number(), action->get_tid());
-                       fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number());
+                       if (action->get_reads_from()!=NULL)
+                               fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number());
                }
                if (thread_array[action->get_tid()] != NULL) {
                        fprintf(file, "N%u -> N%u[label=\"sb\", color=blue];\n", thread_array[action->get_tid()]->get_seq_number(), action->get_seq_number());
@@@ -1691,35 -1701,12 +1708,35 @@@ void ModelChecker::remove_thread(Threa
        scheduler->remove_thread(t);
  }
  
 +/**
 + * @brief Get a Thread reference by its ID
 + * @param tid The Thread's ID
 + * @return A Thread reference
 + */
 +Thread * ModelChecker::get_thread(thread_id_t tid)
 +{
 +      return thread_map->get(id_to_int(tid));
 +}
 +
 +/**
 + * @brief Get a reference to the Thread in which a ModelAction was executed
 + * @param act The ModelAction
 + * @return A Thread reference
 + */
 +Thread * ModelChecker::get_thread(ModelAction *act)
 +{
 +      return get_thread(act->get_tid());
 +}
 +
  /**
   * Switch from a user-context to the "master thread" context (a.k.a. system
   * context). This switch is made with the intention of exploring a particular
   * model-checking action (described by a ModelAction object). Must be called
   * from a user-thread context.
 - * @param act The current action that will be explored. Must not be NULL.
 + *
 + * @param act The current action that will be explored. May be NULL only if
 + * trace is exiting via an assertion (see ModelChecker::set_assert and
 + * ModelChecker::has_asserted).
   * @return Return status from the 'swap' call (i.e., success/fail, 0/-1)
   */
  int ModelChecker::switch_to_master(ModelAction *act)