Merge branch 'master' of ssh://demsky.eecs.uci.edu/home/git/model-checker

[model-checker.git] / action.cc

diff --git a/action.cc b/action.cc
index eb2f0c61f024e64fed76bc85131c47193cfe4d8f..6ae1d861150151133b7b878525705aac9fa5e910 100644 (file)
--- a/action.cc
+++ b/action.cc
@@ -2,6 +2,8 @@
 
 #include "model.h"
 #include "action.h"
+#include "clockvector.h"
+#include "common.h"
 
 ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int value)
 {
@@ -14,6 +16,14 @@ ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int
        act->tid = t->get_id();
        act->value = value;
        act->seq_number = model->get_next_seq_num();
+
+       cv = NULL;
+}
+
+ModelAction::~ModelAction()
+{
+       if (cv)
+               delete cv;
 }
 
 bool ModelAction::is_read()
@@ -26,6 +36,11 @@ bool ModelAction::is_write()
        return type == ATOMIC_WRITE;
 }
 
+bool ModelAction::is_rmw()
+{
+       return type == ATOMIC_RMW;
+}
+
 bool ModelAction::is_acquire()
 {
        switch (order) {
@@ -50,10 +65,14 @@ bool ModelAction::is_release()
        }
 }
 
+bool ModelAction::is_seqcst()
+{
+       return order==memory_order_seq_cst;
+}
+
 bool ModelAction::same_var(ModelAction *act)
 {
-       return true;
-       // TODO: fix stack allocation... return location == act->location;
+       return location == act->location;
 }
 
 bool ModelAction::same_thread(ModelAction *act)
@@ -61,18 +80,60 @@ bool ModelAction::same_thread(ModelAction *act)
        return tid == act->tid;
 }
 
-bool ModelAction::is_dependent(ModelAction *act)
+/** The is_synchronizing method should only explore interleavings if:
+ *  (1) the operations are seq_cst and don't commute or
+ *  (2) the reordering may establish or break a synchronization relation.
+ *  Other memory operations will be dealt with by using the reads_from
+ *  relation.
+ *
+ *  @param act is the action to consider exploring a reordering.
+ *  @return tells whether we have to explore a reordering.
+ */
+
+bool ModelAction::is_synchronizing(ModelAction *act)
 {
-       if (!is_read() && !is_write())
+       //Same thread can't be reordered
+       if (same_thread(act))
                return false;
-       if (!act->is_read() && !act->is_write())
+
+       // Different locations commute
+       if (!same_var(act))
                return false;
-       if (same_var(act) && !same_thread(act) &&
-                       (is_write() || act->is_write()))
+       
+       // Explore interleavings of seqcst writes to guarantee total order
+       // of seq_cst operations that don't commute
+       if (is_write() && is_seqcst() && act->is_write() && act->is_seqcst())
                return true;
+
+       // Explore synchronizing read/write pairs
+       if (is_read() && is_acquire() && act->is_write() && act->is_release())
+               return true;
+       if (is_write() && is_release() && act->is_read() && act->is_acquire())
+               return true;
+
+       // Otherwise handle by reads_from relation
        return false;
 }
 
+void ModelAction::create_cv(ModelAction *parent)
+{
+       if (cv)
+               return;
+
+       if (parent)
+               cv = new ClockVector(parent->cv, this);
+       else
+               cv = new ClockVector(NULL, this);
+}
+
+void ModelAction::read_from(ModelAction *act)
+{
+       ASSERT(cv);
+       if (act->is_release() && this->is_acquire())
+               cv->merge(act->cv);
+       value = act->value;
+}
+
 void ModelAction::print(void)
 {
        const char *type_str;
@@ -92,10 +153,18 @@ void ModelAction::print(void)
        case ATOMIC_WRITE:
                type_str = "atomic write";
                break;
+       case ATOMIC_RMW:
+               type_str = "atomic rmw";
+               break;
        default:
                type_str = "unknown type";
        }
 
-       printf("(%4d) Thread: %d\tAction: %s\tMO: %d\tLoc: %14p\tValue: %d\n",
+       printf("(%3d) Thread: %-2d    Action: %-13s    MO: %d    Loc: %14p    Value: %d",
                        seq_number, id_to_int(tid), type_str, order, location, value);
+       if (cv) {
+               printf("\t");
+               cv->print();
+       } else
+               printf("\n");
 }