#include "clockvector.h"
#include "common.h"
-ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int value)
+ModelAction::ModelAction(action_type_t type, memory_order order, void *loc, int value) :
+ type(type),
+ order(order),
+ location(loc),
+ value(value),
+ reads_from(NULL),
+ cv(NULL)
{
Thread *t = thread_current();
- ModelAction *act = this;
-
- act->type = type;
- act->order = order;
- act->location = loc;
- act->tid = t->get_id();
- act->value = value;
- act->seq_number = model->get_next_seq_num();
-
- cv = NULL;
+ this->tid = t->get_id();
+ this->seq_number = model->get_next_seq_num();
}
ModelAction::~ModelAction()
delete cv;
}
-bool ModelAction::is_read()
+bool ModelAction::is_read() const
{
return type == ATOMIC_READ;
}
-bool ModelAction::is_write()
+bool ModelAction::is_write() const
+{
+ return type == ATOMIC_WRITE || type == ATOMIC_INIT;
+}
+
+bool ModelAction::is_rmw() const
+{
+ return type == ATOMIC_RMW;
+}
+
+bool ModelAction::is_initialization() const
{
- return type == ATOMIC_WRITE;
+ return type == ATOMIC_INIT;
}
-bool ModelAction::is_acquire()
+bool ModelAction::is_acquire() const
{
switch (order) {
case memory_order_acquire:
}
}
-bool ModelAction::is_release()
+bool ModelAction::is_release() const
{
switch (order) {
case memory_order_release:
}
}
-bool ModelAction::same_var(ModelAction *act)
+bool ModelAction::is_seqcst() const
+{
+ return order==memory_order_seq_cst;
+}
+
+bool ModelAction::same_var(const ModelAction *act) const
{
return location == act->location;
}
-bool ModelAction::same_thread(ModelAction *act)
+bool ModelAction::same_thread(const ModelAction *act) const
{
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(const ModelAction *act) const
{
- 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)
+void ModelAction::create_cv(const ModelAction *parent)
{
ASSERT(cv == NULL);
+
if (parent)
cv = new ClockVector(parent->cv, this);
else
- cv = new ClockVector();
+ cv = new ClockVector(NULL, this);
}
-void ModelAction::read_from(ModelAction *act)
+void ModelAction::read_from(const ModelAction *act)
{
ASSERT(cv);
if (act->is_release() && this->is_acquire())
cv->merge(act->cv);
+ reads_from = act;
value = act->value;
}
-void ModelAction::print(void)
+/**
+ * Check whether 'this' happens before act, according to the memory-model's
+ * happens before relation. This is checked via the ClockVector constructs.
+ * @return true if this action's thread has synchronized with act's thread
+ * since the execution of act, false otherwise.
+ */
+bool ModelAction::happens_before(const ModelAction *act) const
+{
+ return act->cv->synchronized_since(this);
+}
+
+void ModelAction::print(void) const
{
const char *type_str;
switch (this->type) {
case THREAD_CREATE:
type_str = "thread create";
break;
+ case THREAD_START:
+ type_str = "thread start";
+ break;
case THREAD_YIELD:
type_str = "thread yield";
break;
case ATOMIC_WRITE:
type_str = "atomic write";
break;
+ case ATOMIC_RMW:
+ type_str = "atomic rmw";
+ break;
+ case ATOMIC_INIT:
+ type_str = "init atomic";
+ 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: %-4d",
seq_number, id_to_int(tid), type_str, order, location, value);
+ if (reads_from)
+ printf(" Rf: %d", reads_from->get_seq_number());
+ if (cv) {
+ printf("\t");
+ cv->print();
+ } else
+ printf("\n");
}