X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=history.cc;h=f1060ca996e7949214d200e59aa0aa2c1b5a5dd0;hp=ee4c90a0934240060b62c581840bef111485c5c3;hb=da918c450a8fb8524ed99da0a35a7e417eb85777;hpb=44870f54a17bd7a61a94465aec78144c689e336b

diff --git a/history.cc b/history.cc
index ee4c90a0..f1060ca9 100644
--- a/history.cc
+++ b/history.cc
@@ -2,74 +2,119 @@
 #include "history.h"
 #include "action.h"
 #include "funcnode.h"
+#include "funcinst.h"
 #include "common.h"
+#include "concretepredicate.h"
+#include "waitobj.h"
 
 #include "model.h"
 #include "execution.h"
-
+#include "newfuzzer.h"
 
 /** @brief Constructor */
 ModelHistory::ModelHistory() :
-	func_counter(1), /* function id starts with 1 */
+	func_counter(1),	/* function id starts with 1 */
 	func_map(),
 	func_map_rev(),
 	func_nodes()
-{}
+{
+	/* The following are snapshot data structures */
+	write_history = new HashTable<void *, value_set_t *, uintptr_t, 0>();
+	loc_rd_func_nodes_map = new HashTable<void *, SnapVector<FuncNode *> *, uintptr_t, 0>();
+	loc_wr_func_nodes_map = new HashTable<void *, SnapVector<FuncNode *> *, uintptr_t, 0>();
+	loc_waiting_writes_map = new HashTable<void *, SnapVector<ConcretePredicate *> *, uintptr_t, 0>();
+	thrd_func_act_lists = new SnapVector< SnapList<action_list_t *> *>();
+	thrd_func_list = new SnapVector<func_id_list_t>();
+	thrd_last_entered_func = new SnapVector<uint32_t>();
+	thrd_waiting_write = new SnapVector<ConcretePredicate *>();
+	thrd_wait_obj = new SnapVector<WaitObj *>();
+	func_inst_act_maps = new HashTable<uint32_t, SnapVector<inst_act_map_t *> *, int, 0>(128);
+}
+
+ModelHistory::~ModelHistory()
+{
+	// TODO: complete deconstructor; maybe not needed
+	for (uint i = 0;i < thrd_wait_obj->size();i++)
+		delete (*thrd_wait_obj)[i];
+}
 
 void ModelHistory::enter_function(const uint32_t func_id, thread_id_t tid)
 {
 	//model_print("thread %d entering func %d\n", tid, func_id);
-	uint32_t id = id_to_int(tid);
-	SnapVector<func_id_list_t *> * thrd_func_list = model->get_execution()->get_thrd_func_list();
-	SnapVector< SnapList<func_inst_list_t *> *> *
-			thrd_func_inst_lists = model->get_execution()->get_thrd_func_inst_lists();
+	uint id = id_to_int(tid);
 
 	if ( thrd_func_list->size() <= id ) {
+		uint oldsize = thrd_func_list->size();
 		thrd_func_list->resize( id + 1 );
-		thrd_func_inst_lists->resize( id + 1 );
-	}
+		thrd_func_act_lists->resize( id + 1 );
 
-	func_id_list_t * func_list = thrd_func_list->at(id);
-	SnapList<func_inst_list_t *> * func_inst_lists = thrd_func_inst_lists->at(id);
+		for (uint i = oldsize;i < id + 1;i++) {
+			// push 0 as a dummy function id to a void seg fault
+			new (&(*thrd_func_list)[i]) func_id_list_t();
+			(*thrd_func_list)[i].push_back(0);
 
-	if (func_list == NULL) {
-		func_list = new func_id_list_t();
-		thrd_func_list->at(id) = func_list;
+			(*thrd_func_act_lists)[i] = new SnapList<action_list_t *>();
+			thrd_last_entered_func->push_back(0);
+		}
 	}
 
-	if (func_inst_lists == NULL) {
-		func_inst_lists = new SnapList< func_inst_list_t *>();
-		thrd_func_inst_lists->at(id) = func_inst_lists;
+	SnapList<action_list_t *> * func_act_lists = (*thrd_func_act_lists)[id];
+	func_act_lists->push_back( new action_list_t() );
+
+	uint32_t last_entered_func_id = (*thrd_last_entered_func)[id];
+	(*thrd_last_entered_func)[id] = func_id;
+	(*thrd_func_list)[id].push_back(func_id);
+
+	if ( func_nodes.size() <= func_id )
+		resize_func_nodes( func_id + 1 );
+
+	FuncNode * func_node = func_nodes[func_id];
+	func_node->init_predicate_tree_position(tid);
+	func_node->init_inst_act_map(tid);
+
+	/* Add edges between FuncNodes */
+	if (last_entered_func_id != 0) {
+		FuncNode * last_func_node = func_nodes[last_entered_func_id];
+		last_func_node->add_out_edge(func_node);
 	}
 
-	func_list->push_back(func_id);
-	func_inst_lists->push_back( new func_inst_list_t() );
+	/* Monitor the statuses of threads waiting for tid */
+	monitor_waiting_thread(func_id, tid);
 }
 
 /* @param func_id a non-zero value */
 void ModelHistory::exit_function(const uint32_t func_id, thread_id_t tid)
 {
 	uint32_t id = id_to_int(tid);
-	SnapVector<func_id_list_t *> * thrd_func_list = model->get_execution()->get_thrd_func_list();
-	SnapVector< SnapList<func_inst_list_t *> *> *
-			thrd_func_inst_lists = model->get_execution()->get_thrd_func_inst_lists();
 
-	func_id_list_t * func_list = thrd_func_list->at(id);
-	SnapList<func_inst_list_t *> * func_inst_lists = thrd_func_inst_lists->at(id);
-
-	uint32_t last_func_id = func_list->back();
+	SnapList<action_list_t *> * func_act_lists = (*thrd_func_act_lists)[id];
+	uint32_t last_func_id = (*thrd_func_list)[id].back();
 
 	if (last_func_id == func_id) {
-		func_list->pop_back();
-
-		/* clear read map upon exiting functions */
 		FuncNode * func_node = func_nodes[func_id];
-		func_node->clear_read_map(tid);
-
-		func_inst_list_t * curr_inst_list = func_inst_lists->back();
-		func_node->link_insts(curr_inst_list);
-
-		func_inst_lists->pop_back();
+		func_node->set_predicate_tree_position(tid, NULL);
+		func_node->reset_inst_act_map(tid);
+
+		action_list_t * curr_act_list = func_act_lists->back();
+
+		/* defer the processing of curr_act_list until the function has exits a few times
+		 * (currently twice) so that more information can be gathered to infer nullity predicates.
+		 */
+		func_node->incr_exit_count();
+		if (func_node->get_exit_count() >= 2) {
+			SnapList<action_list_t *> * action_list_buffer = func_node->get_action_list_buffer();
+			while (action_list_buffer->size() > 0) {
+				action_list_t * act_list = action_list_buffer->back();
+				action_list_buffer->pop_back();
+				func_node->update_tree(act_list);
+			}
+
+			func_node->update_tree(curr_act_list);
+		} else
+			func_node->get_action_list_buffer()->push_front(curr_act_list);
+
+		(*thrd_func_list)[id].pop_back();
+		func_act_lists->pop_back();
 	} else {
 		model_print("trying to exit with a wrong function id\n");
 		model_print("--- last_func: %d, func_id: %d\n", last_func_id, func_id);
@@ -77,78 +122,478 @@ void ModelHistory::exit_function(const uint32_t func_id, thread_id_t tid)
 	//model_print("thread %d exiting func %d\n", tid, func_id);
 }
 
-void ModelHistory::process_action(ModelAction *act, thread_id_t tid)
+void ModelHistory::resize_func_nodes(uint32_t new_size)
 {
-	/* return if thread i has not entered any function or has exited
-	   from all functions */
-	SnapVector<func_id_list_t *> * thrd_func_list = model->get_execution()->get_thrd_func_list();
-	SnapVector< SnapList<func_inst_list_t *> *> *
-			thrd_func_inst_lists = model->get_execution()->get_thrd_func_inst_lists();
+	uint32_t old_size = func_nodes.size();
 
-	uint32_t id = id_to_int(tid);
-	if ( thrd_func_list->size() <= id )
+	if ( old_size < new_size )
+		func_nodes.resize(new_size);
+
+	for (uint32_t id = old_size;id < new_size;id++) {
+		const char * func_name = func_map_rev[id];
+		FuncNode * func_node = new FuncNode(this);
+		func_node->set_func_id(id);
+		func_node->set_func_name(func_name);
+		func_nodes[id] = func_node;
+	}
+}
+
+void ModelHistory::process_action(ModelAction *act, thread_id_t tid)
+{
+	uint32_t thread_id = id_to_int(tid);
+	/* Return if thread tid has not entered any function that contains atomics */
+	if ( thrd_func_list->size() <= thread_id )
 		return;
-	else if (thrd_func_list->at(id) == NULL)
+
+	/* Monitor the statuses of threads waiting for tid */
+	monitor_waiting_thread_counter(tid);
+
+	/* Every write action should be processed, including
+	 * nonatomic writes (which have no position) */
+	if (act->is_write()) {
+		void * location = act->get_location();
+		uint64_t value = act->get_write_value();
+		update_write_history(location, value);
+
+		/* Notify FuncNodes that may read from this location */
+		SnapVector<FuncNode *> * func_node_list = getRdFuncNodes(location);
+		for (uint i = 0;i < func_node_list->size();i++) {
+			FuncNode * func_node = (*func_node_list)[i];
+			func_node->add_to_val_loc_map(value, location);
+		}
+
+		// check_waiting_write(act);
+	}
+
+	uint32_t func_id = (*thrd_func_list)[thread_id].back();
+
+	/* The following does not care about actions that are not inside
+	 * any function that contains atomics or actions without a position */
+	if (func_id == 0 || act->get_position() == NULL)
 		return;
 
-	/* get the function id that thread i is currently in */
-	func_id_list_t * func_list = thrd_func_list->at(id);
-	SnapList<func_inst_list_t *> * func_inst_lists = thrd_func_inst_lists->at(id);
+	SnapList<action_list_t *> * func_act_lists = (*thrd_func_act_lists)[thread_id];
 
-	uint32_t func_id = func_list->back();
+	/* The list of actions that thread tid has taken in its current function */
+	action_list_t * curr_act_list = func_act_lists->back();
 
-	if ( func_nodes.size() <= func_id )
-		func_nodes.resize( func_id + 1 );
+	if (skip_action(act, curr_act_list))
+		return;
+
+	/* Add to curr_inst_list */
+	curr_act_list->push_back(act);
 
 	FuncNode * func_node = func_nodes[func_id];
-	if (func_node == NULL) {
-		const char * func_name = func_map_rev[func_id];
-		func_node = new FuncNode();
-		func_node->set_func_id(func_id);
-		func_node->set_func_name(func_name);
+	func_node->add_inst(act);
+
+	if (act->is_read()) {
+		func_node->update_inst_act_map(tid, act);
+
+		Fuzzer * fuzzer = model->get_execution()->getFuzzer();
+		Predicate * selected_branch = fuzzer->get_selected_child_branch(tid);
+		func_node->set_predicate_tree_position(tid, selected_branch);
+	}
+
+	if (act->is_write()) {
+		Predicate * curr_pred = func_node->get_predicate_tree_position(tid);
+		FuncInst * curr_inst = func_node->get_inst(act);
+
+		if (curr_pred) {
+			// Follow child
+			curr_pred = curr_pred->get_single_child(curr_inst);
+		}
+		func_node->set_predicate_tree_position(tid, curr_pred);
+	}
+}
+
+/* Return the FuncNode given its func_id  */
+FuncNode * ModelHistory::get_func_node(uint32_t func_id)
+{
+	if (func_id == 0)
+		return NULL;
+
+	// This node has not been added to func_nodes
+	if (func_nodes.size() <= func_id)
+		return NULL;
+
+	return func_nodes[func_id];
+}
+
+/* Return the current FuncNode when given a thread id */
+FuncNode * ModelHistory::get_curr_func_node(thread_id_t tid)
+{
+	int thread_id = id_to_int(tid);
+	uint32_t func_id = (*thrd_func_list)[thread_id].back();
+
+	if (func_id != 0) {
+		return func_nodes[func_id];
+	}
+
+	return NULL;
+}
+
+void ModelHistory::update_write_history(void * location, uint64_t write_val)
+{
+	value_set_t * write_set = write_history->get(location);
+
+	if (write_set == NULL) {
+		write_set = new value_set_t();
+		write_history->put(location, write_set);
+	}
+
+	write_set->add(write_val);
+}
+
+void ModelHistory::update_loc_rd_func_nodes_map(void * location, FuncNode * node)
+{
+	SnapVector<FuncNode *> * func_node_list = getRdFuncNodes(location);
+	func_node_list->push_back(node);
+}
+
+void ModelHistory::update_loc_wr_func_nodes_map(void * location, FuncNode * node)
+{
+	SnapVector<FuncNode *> * func_node_list = getWrFuncNodes(location);
+	func_node_list->push_back(node);
+}
+
+SnapVector<FuncNode *> * ModelHistory::getRdFuncNodes(void * location)
+{
+	SnapVector<FuncNode *> * func_node_list = loc_rd_func_nodes_map->get(location);
+	if (func_node_list == NULL) {
+		func_node_list = new SnapVector<FuncNode *>();
+		loc_rd_func_nodes_map->put(location, func_node_list);
+	}
+
+	return func_node_list;
+}
+
+SnapVector<FuncNode *> * ModelHistory::getWrFuncNodes(void * location)
+{
+	SnapVector<FuncNode *> * func_node_list = loc_wr_func_nodes_map->get(location);
+	if (func_node_list == NULL) {
+		func_node_list = new SnapVector<FuncNode *>();
+		loc_wr_func_nodes_map->put(location, func_node_list);
+	}
 
-		func_nodes[func_id] = func_node;
+	return func_node_list;
+}
+
+/* When a thread is paused by Fuzzer, keep track of the condition it is waiting for */
+void ModelHistory::add_waiting_write(ConcretePredicate * concrete)
+{
+	void * location = concrete->get_location();
+	SnapVector<ConcretePredicate *> * waiting_conditions = loc_waiting_writes_map->get(location);
+	if (waiting_conditions == NULL) {
+		waiting_conditions = new SnapVector<ConcretePredicate *>();
+		loc_waiting_writes_map->put(location, waiting_conditions);
 	}
 
-	/* add corresponding FuncInst to func_node */
-	FuncInst * inst = func_node->get_or_add_action(act);
+	/* waiting_conditions should not have duplications */
+	waiting_conditions->push_back(concrete);
 
-	if (inst == NULL)
+	int thread_id = id_to_int(concrete->get_tid());
+	if (thrd_waiting_write->size() <= (uint) thread_id) {
+		thrd_waiting_write->resize(thread_id + 1);
+	}
+
+	(*thrd_waiting_write)[thread_id] = concrete;
+}
+
+void ModelHistory::remove_waiting_write(thread_id_t tid)
+{
+	ConcretePredicate * concrete = (*thrd_waiting_write)[ id_to_int(tid) ];
+	void * location = concrete->get_location();
+	SnapVector<ConcretePredicate *> * concrete_preds = loc_waiting_writes_map->get(location);
+
+	/* Linear search should be fine because presumably not many ConcretePredicates
+	 * are at the same memory location */
+	for (uint i = 0;i < concrete_preds->size();i++) {
+		ConcretePredicate * current = (*concrete_preds)[i];
+		if (concrete == current) {
+			(*concrete_preds)[i] = concrete_preds->back();
+			concrete_preds->pop_back();
+			break;
+		}
+	}
+
+	int thread_id = id_to_int( concrete->get_tid() );
+	(*thrd_waiting_write)[thread_id] = NULL;
+	delete concrete;
+}
+
+/* Check if any other thread is waiting for this write action. If so, "notify" them */
+void ModelHistory::check_waiting_write(ModelAction * write_act)
+{
+	void * location = write_act->get_location();
+	uint64_t value = write_act->get_write_value();
+	SnapVector<ConcretePredicate *> * concrete_preds = loc_waiting_writes_map->get(location);
+	if (concrete_preds == NULL)
 		return;
 
-	if (inst->is_read())
-		func_node->store_read(act, tid);
+	uint index = 0;
+	while (index < concrete_preds->size()) {
+		ConcretePredicate * concrete_pred = (*concrete_preds)[index];
+		SnapVector<struct concrete_pred_expr> * concrete_exprs = concrete_pred->getExpressions();
+		bool satisfy_predicate = true;
+		/* Check if the written value satisfies every predicate expression */
+		for (uint i = 0;i < concrete_exprs->size();i++) {
+			struct concrete_pred_expr concrete = (*concrete_exprs)[i];
+			bool equality = false;
+			switch (concrete.token) {
+			case EQUALITY:
+				equality = (value == concrete.value);
+				break;
+			case NULLITY:
+				equality = ((void*)value == NULL);
+				break;
+			default:
+				model_print("unknown predicate token");
+				break;
+			}
+
+			if (equality != concrete.equality) {
+				satisfy_predicate = false;
+				break;
+			}
+		}
+
+		if (satisfy_predicate) {
+			/* Wake up threads */
+			thread_id_t tid = concrete_pred->get_tid();
+			Thread * thread = model->get_thread(tid);
+
+			//model_print("** thread %d is woken up\n", thread->get_id());
+			model->get_execution()->getFuzzer()->notify_paused_thread(thread);
+		}
 
-	/* add to curr_inst_list */
-	func_inst_list_t * curr_inst_list = func_inst_lists->back();
-	ASSERT(curr_inst_list != NULL);
-	curr_inst_list->push_back(inst);
+		index++;
+	}
 }
 
-void ModelHistory::print()
+WaitObj * ModelHistory::getWaitObj(thread_id_t tid)
 {
-	/* function id starts with 1 */
-	for (uint32_t i = 1; i < func_nodes.size(); i++) {
-		FuncNode * func_node = func_nodes[i];
+	int thread_id = id_to_int(tid);
+	int old_size = thrd_wait_obj->size();
+	if (old_size <= thread_id) {
+		thrd_wait_obj->resize(thread_id + 1);
+		for (int i = old_size;i < thread_id + 1;i++) {
+			(*thrd_wait_obj)[i] = new WaitObj( int_to_id(i) );
+		}
+	}
 
-		func_inst_list_mt * entry_insts = func_node->get_entry_insts();
-		model_print("function %s has entry actions\n", func_node->get_func_name());
+	return (*thrd_wait_obj)[thread_id];
+}
+
+void ModelHistory::add_waiting_thread(thread_id_t self_id,
+thread_id_t waiting_for_id, FuncNode * target_node, int dist)
+{
+	WaitObj * self_wait_obj = getWaitObj(self_id);
+	self_wait_obj->add_waiting_for(waiting_for_id, target_node, dist);
+
+	/* Update waited-by relation */
+	WaitObj * other_wait_obj = getWaitObj(waiting_for_id);
+	other_wait_obj->add_waited_by(self_id);
+}
+
+/* Thread tid is woken up (or notified), so it is not waiting for others anymore */
+void ModelHistory::remove_waiting_thread(thread_id_t tid)
+{
+	WaitObj * self_wait_obj = getWaitObj(tid);
+	thrd_id_set_t * waiting_for = self_wait_obj->getWaitingFor();
+
+	/* Remove tid from waited_by's */
+	thrd_id_set_iter * iter = waiting_for->iterator();
+	while (iter->hasNext()) {
+		thread_id_t other_id = iter->next();
+		WaitObj * other_wait_obj = getWaitObj(other_id);
+		other_wait_obj->remove_waited_by(tid);
+	}
+
+	self_wait_obj->clear_waiting_for();
+}
 
-		func_inst_list_mt::iterator it;
-		for (it = entry_insts->begin(); it != entry_insts->end(); it++) {
-			FuncInst *inst = *it;
-			model_print("type: %d, at: %s\n", inst->get_type(), inst->get_position());
+void ModelHistory::stop_waiting_for_node(thread_id_t self_id,
+thread_id_t waiting_for_id, FuncNode * target_node)
+{
+	WaitObj * self_wait_obj = getWaitObj(self_id);
+	bool thread_removed = self_wait_obj->remove_waiting_for_node(waiting_for_id, target_node);
+
+	// model_print("\t%d gives up %d on node %d\n", self_id, waiting_for_id, target_node->get_func_id());
+
+	/* If thread self_id is not waiting for waiting_for_id anymore */
+	if (thread_removed) {
+		WaitObj * other_wait_obj = getWaitObj(waiting_for_id);
+		other_wait_obj->remove_waited_by(self_id);
+
+		thrd_id_set_t * self_waiting_for = self_wait_obj->getWaitingFor();
+		if ( self_waiting_for->isEmpty() ) {
+			// model_print("\tthread %d waits for nobody, wake up\n", self_id);
+			ModelExecution * execution = model->get_execution();
+			Thread * thread = execution->get_thread(self_id);
+			execution->getFuzzer()->notify_paused_thread(thread);
 		}
+	}
+}
 
-/*
-		func_inst_list_mt * inst_list = funcNode->get_inst_list();
+SnapVector<inst_act_map_t *> * ModelHistory::getThrdInstActMap(uint32_t func_id)
+{
+	ASSERT(func_id != 0);
 
-		model_print("function %s has following actions\n", funcNode->get_func_name());
-		func_inst_list_mt::iterator it;
-		for (it = inst_list->begin(); it != inst_list->end(); it++) {
-			FuncInst *inst = *it;
-			model_print("type: %d, at: %s\n", inst->get_type(), inst->get_position());
+	SnapVector<inst_act_map_t *> * maps = func_inst_act_maps->get(func_id);
+	if (maps == NULL) {
+		maps = new SnapVector<inst_act_map_t *>();
+		func_inst_act_maps->put(func_id, maps);
+	}
+
+	return maps;
+}
+
+bool ModelHistory::skip_action(ModelAction * act, SnapList<ModelAction *> * curr_act_list)
+{
+	ASSERT(curr_act_list != NULL);
+
+	bool second_part_of_rmw = act->is_rmwc() || act->is_rmw();
+	modelclock_t curr_seq_number = act->get_seq_number();
+
+	/* Skip actions that are second part of a read modify write */
+	if (second_part_of_rmw)
+		return true;
+
+	/* Skip actions with the same sequence number */
+	if (curr_act_list->size() != 0) {
+		ModelAction * last_act = curr_act_list->back();
+		if (last_act->get_seq_number() == curr_seq_number)
+			return true;
+	}
+
+	/* Skip actions that are paused by fuzzer (sequence number is 0) */
+	if (curr_seq_number == 0)
+		return true;
+
+	return false;
+}
+
+/* Monitor thread tid and decide whether other threads (that are waiting for tid)
+ * should keep waiting for this thread or not. Shall only be called when a thread
+ * enters a function.
+ *
+ * Heuristics: If the distance from the current FuncNode to some target node
+ * ever increases, stop waiting for this thread on this target node.
+ */
+void ModelHistory::monitor_waiting_thread(uint32_t func_id, thread_id_t tid)
+{
+	WaitObj * wait_obj = getWaitObj(tid);
+	thrd_id_set_t * waited_by = wait_obj->getWaitedBy();
+	FuncNode * curr_node = func_nodes[func_id];
+
+	/* For each thread waiting for tid */
+	thrd_id_set_iter * tid_iter = waited_by->iterator();
+	while (tid_iter->hasNext()) {
+		thread_id_t waited_by_id = tid_iter->next();
+		WaitObj * other_wait_obj = getWaitObj(waited_by_id);
+
+		node_set_t * target_nodes = other_wait_obj->getTargetNodes(tid);
+		node_set_iter * node_iter = target_nodes->iterator();
+		while (node_iter->hasNext()) {
+			FuncNode * target = node_iter->next();
+			int old_dist = other_wait_obj->lookup_dist(tid, target);
+			int new_dist = curr_node->compute_distance(target, old_dist);
+
+			if (new_dist == -1) {
+				stop_waiting_for_node(waited_by_id, tid, target);
+			}
+		}
+	}
+}
+
+void ModelHistory::monitor_waiting_thread_counter(thread_id_t tid)
+{
+	WaitObj * wait_obj = getWaitObj(tid);
+	thrd_id_set_t * waited_by = wait_obj->getWaitedBy();
+
+	// Thread tid has taken an action, update the counter for threads waiting for tid
+	thrd_id_set_iter * tid_iter = waited_by->iterator();
+	while (tid_iter->hasNext()) {
+		thread_id_t waited_by_id = tid_iter->next();
+		WaitObj * other_wait_obj = getWaitObj(waited_by_id);
+
+		bool expire = other_wait_obj->incr_counter(tid);
+		if (expire) {
+//			model_print("thread %d stops waiting for thread %d\n", waited_by_id, tid);
+			wait_obj->remove_waited_by(waited_by_id);
+			other_wait_obj->remove_waiting_for(tid);
+
+			thrd_id_set_t * other_waiting_for = other_wait_obj->getWaitingFor();
+			if ( other_waiting_for->isEmpty() ) {
+				// model_print("\tthread %d waits for nobody, wake up\n", self_id);
+				ModelExecution * execution = model->get_execution();
+				Thread * thread = execution->get_thread(waited_by_id);
+				execution->getFuzzer()->notify_paused_thread(thread);
+			}
 		}
-*/
+	}
+}
+
+/* Reallocate some snapshotted memories when new executions start */
+void ModelHistory::set_new_exec_flag()
+{
+	for (uint i = 1;i < func_nodes.size();i++) {
+		FuncNode * func_node = func_nodes[i];
+		func_node->set_new_exec_flag();
+	}
+}
+
+void ModelHistory::dump_func_node_graph()
+{
+	model_print("digraph func_node_graph {\n");
+	for (uint i = 1;i < func_nodes.size();i++) {
+		FuncNode * node = func_nodes[i];
+		ModelList<FuncNode *> * out_edges = node->get_out_edges();
+
+		model_print("\"%p\" [label=\"%s\"]\n", node, node->get_func_name());
+		mllnode<FuncNode *> * it;
+		for (it = out_edges->begin();it != NULL;it = it->getNext()) {
+			FuncNode * other = it->getVal();
+			model_print("\"%p\" -> \"%p\"\n", node, other);
+		}
+	}
+	model_print("}\n");
+}
+
+void ModelHistory::print_func_node()
+{
+	/* function id starts with 1 */
+	for (uint32_t i = 1;i < func_nodes.size();i++) {
+		FuncNode * func_node = func_nodes[i];
+
+		func_node->assign_base_score();
+		func_node->print_predicate_tree();
+
+/*
+                func_inst_list_mt * entry_insts = func_node->get_entry_insts();
+                model_print("function %s has entry actions\n", func_node->get_func_name());
+
+                mllnode<FuncInst*>* it;
+                for (it = entry_insts->begin();it != NULL;it=it->getNext()) {
+                        FuncInst *inst = it->getVal();
+                        model_print("type: %d, at: %s\n", inst->get_type(), inst->get_position());
+                }
+ */
+	}
+}
+
+void ModelHistory::print_waiting_threads()
+{
+	ModelExecution * execution = model->get_execution();
+	for (unsigned int i = 0;i < execution->get_num_threads();i++) {
+		thread_id_t tid = int_to_id(i);
+		WaitObj * wait_obj = getWaitObj(tid);
+		wait_obj->print_waiting_for();
+	}
+
+	for (unsigned int i = 0;i < execution->get_num_threads();i++) {
+		thread_id_t tid = int_to_id(i);
+		WaitObj * wait_obj = getWaitObj(tid);
+		wait_obj->print_waited_by();
 	}
 }