Fix bug
[c11tester.git] / funcnode.cc
index 4c49f2c315275d371fb48c3c19b9c3ece0476a3e..8cb39da9697efbbe0f7a8da397c2988f314f2c57 100644 (file)
+#include "action.h"
+#include "history.h"
 #include "funcnode.h"
+#include "funcinst.h"
 #include "predicate.h"
+#include "concretepredicate.h"
 
-FuncNode::FuncNode() :
+#include "model.h"
+
+FuncNode::FuncNode(ModelHistory * history) :
+       history(history),
+       exit_count(0),
+       marker(1),
        func_inst_map(),
        inst_list(),
        entry_insts(),
-       thrd_read_map(),
-       read_locations()
-{}
+       predicate_tree_position(),
+       edge_table(32),
+       out_edges()
+{
+       predicate_tree_entry = new Predicate(NULL, true);
+       predicate_tree_entry->add_predicate_expr(NOPREDICATE, NULL, true);
+       predicate_tree_exit = new Predicate(NULL, false, true);
+
+       // Memories that are reclaimed after each execution
+       action_list_buffer = new SnapList<action_list_t *>();
+       read_locations = new loc_set_t();
+       write_locations = new loc_set_t();
+       val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
+       loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
+
+       //values_may_read_from = new value_set_t();
+}
+
+/* Reallocate snapshotted memories when new executions start */
+void FuncNode::set_new_exec_flag()
+{
+       action_list_buffer = new SnapList<action_list_t *>();
+       read_locations = new loc_set_t();
+       write_locations = new loc_set_t();
+       val_loc_map = new HashTable<uint64_t, loc_set_t *, uint64_t, 0>();
+       loc_may_equal_map = new HashTable<void *, loc_set_t *, uintptr_t, 0>();
+
+       //values_may_read_from = new value_set_t();
+}
 
 /* Check whether FuncInst with the same type, position, and location
- * as act has been added to func_inst_map or not. If so, return it;
- * if not, add it and return it.
+ * as act has been added to func_inst_map or not. If not, add it.
  *
- * @return FuncInst with the same type, position, and location as act */
-FuncInst * FuncNode::get_or_add_action(ModelAction *act)
+ * Note: currently, actions with the same position are filtered out by process_action,
+ * so the collision list of FuncInst is not used. May remove it later. 
+ */
+void FuncNode::add_inst(ModelAction *act)
 {
        ASSERT(act);
        const char * position = act->get_position();
 
-       /* Actions THREAD_CREATE, THREAD_START, THREAD_YIELD, THREAD_JOIN,
-        * THREAD_FINISH, PTHREAD_CREATE, PTHREAD_JOIN,
-        * ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK are not tagged with their
-        * source line numbers
+       /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
+        * actions are not tagged with their source line numbers
         */
        if (position == NULL)
-               return NULL;
+               return;
 
        if ( func_inst_map.contains(position) ) {
                FuncInst * inst = func_inst_map.get(position);
 
-               if (inst->get_type() != act->get_type() ) {
-                       // model_print("action with a different type occurs at line number %s\n", position);
-                       FuncInst * func_inst = inst->search_in_collision(act);
-
-                       if (func_inst != NULL) {
-                               // return the FuncInst found in the collision list
-                               return func_inst;
-                       }
-
-                       func_inst = new FuncInst(act, this);
-                       inst->get_collisions()->push_back(func_inst);
-                       inst_list.push_back(func_inst); // delete?
+               ASSERT(inst->get_type() == act->get_type());
+               int curr_execution_number = model->get_execution_number();
 
-                       return func_inst;
+               /* Reset locations when new executions start */
+               if (inst->get_execution_number() != curr_execution_number) {
+                       inst->set_location(act->get_location());
+                       inst->set_execution_number(curr_execution_number);
                }
 
-               return inst;
+               if (inst->get_location() != act->get_location())
+                       inst->not_single_location();
+
+               return;
        }
 
        FuncInst * func_inst = new FuncInst(act, this);
 
        func_inst_map.put(position, func_inst);
        inst_list.push_back(func_inst);
+}
+
+/* Get the FuncInst with the same type, position, and location
+ * as act
+ *
+ * @return FuncInst with the same type, position, and location as act */
+FuncInst * FuncNode::get_inst(ModelAction *act)
+{
+       ASSERT(act);
+       const char * position = act->get_position();
 
-       return func_inst;
+       /* THREAD* actions, ATOMIC_LOCK, ATOMIC_TRYLOCK, and ATOMIC_UNLOCK
+        * actions are not tagged with their source line numbers
+        */
+       if (position == NULL)
+               return NULL;
+
+       FuncInst * inst = func_inst_map.get(position);
+       if (inst == NULL)
+               return NULL;
+
+       action_type inst_type = inst->get_type();
+       action_type act_type = act->get_type();
+
+       // else if branch: an RMWRCAS action is converted to a RMW or READ action
+       if (inst_type == act_type)
+               return inst;
+       else if (inst_type == ATOMIC_RMWRCAS &&
+                       (act_type == ATOMIC_RMW || act_type == ATOMIC_READ))
+               return inst;
+
+       return NULL;
 }
 
+
 void FuncNode::add_entry_inst(FuncInst * inst)
 {
        if (inst == NULL)
                return;
 
-       func_inst_list_mt::iterator it;
-       for (it = entry_insts.begin();it != entry_insts.end();it++) {
-               if (inst == *it)
+       mllnode<FuncInst *> * it;
+       for (it = entry_insts.begin(); it != NULL; it = it->getNext()) {
+               if (inst == it->getVal())
                        return;
        }
 
        entry_insts.push_back(inst);
 }
 
-/* @param inst_list a list of FuncInsts; this argument comes from ModelExecution
- * Link FuncInsts in a list - add one FuncInst to another's predecessors and successors
+/**
+ * @brief Convert ModelAdtion list to FuncInst list 
+ * @param act_list A list of ModelActions
  */
-void FuncNode::link_insts(func_inst_list_t * inst_list)
+void FuncNode::update_tree(action_list_t * act_list)
 {
-       if (inst_list == NULL)
+       if (act_list == NULL || act_list->size() == 0)
                return;
 
-       func_inst_list_t::iterator it = inst_list->begin();
-       func_inst_list_t::iterator prev;
+       HashTable<void *, value_set_t *, uintptr_t, 0> * write_history = history->getWriteHistory();
+
+       /* build inst_list from act_list for later processing */
+       func_inst_list_t inst_list;
+       action_list_t rw_act_list;
+
+       for (sllnode<ModelAction *> * it = act_list->begin(); it != NULL; it = it->getNext()) {
+               ModelAction * act = it->getVal();
+               FuncInst * func_inst = get_inst(act);
+               void * loc = act->get_location();
+
+               if (func_inst == NULL)
+                       continue;
+
+               inst_list.push_back(func_inst);
+               bool act_added = false;
+
+               if (act->is_write()) {
+                       rw_act_list.push_back(act);
+                       act_added = true;
+                       if (!write_locations->contains(loc)) {
+                               write_locations->add(loc);
+                               history->update_loc_wr_func_nodes_map(loc, this);
+                       }
+               }
+
+               if (act->is_read()) {
+                       if (!act_added)
+                               rw_act_list.push_back(act);
+
+                       /* If func_inst may only read_from a single location, then:
+                        *
+                        * The first time an action reads from some location,
+                        * import all the values that have been written to this
+                        * location from ModelHistory and notify ModelHistory
+                        * that this FuncNode may read from this location.
+                        */
+                       if (!read_locations->contains(loc) && func_inst->is_single_location()) {
+                               read_locations->add(loc);
+                               value_set_t * write_values = write_history->get(loc);
+                               add_to_val_loc_map(write_values, loc);
+                               history->update_loc_rd_func_nodes_map(loc, this);
+                       }
+               }
+       }
 
-       if (inst_list->size() == 0)
+//     model_print("function %s\n", func_name);
+//     print_val_loc_map();
+
+       update_inst_tree(&inst_list);
+       update_predicate_tree(&rw_act_list);
+
+//     print_predicate_tree();
+}
+
+/** 
+ * @brief Link FuncInsts in inst_list  - add one FuncInst to another's predecessors and successors
+ * @param inst_list A list of FuncInsts
+ */
+void FuncNode::update_inst_tree(func_inst_list_t * inst_list)
+{
+       if (inst_list == NULL)
+               return;
+       else if (inst_list->size() == 0)
                return;
 
+       /* start linking */
+       sllnode<FuncInst *>* it = inst_list->begin();
+       sllnode<FuncInst *>* prev;
+
        /* add the first instruction to the list of entry insts */
-       FuncInst * entry_inst = *it;
+       FuncInst * entry_inst = it->getVal();
        add_entry_inst(entry_inst);
 
-       it++;
-       while (it != inst_list->end()) {
-               prev = it;
-               prev--;
+       it = it->getNext();
+       while (it != NULL) {
+               prev = it->getPrev();
 
-               FuncInst * prev_inst = *prev;
-               FuncInst * curr_inst = *it;
+               FuncInst * prev_inst = prev->getVal();
+               FuncInst * curr_inst = it->getVal();
 
                prev_inst->add_succ(curr_inst);
                curr_inst->add_pred(prev_inst);
 
-               it++;
+               it = it->getNext();
        }
 }
 
-/* @param tid thread id
- * Store the values read by atomic read actions into thrd_read_map */
-void FuncNode::store_read(ModelAction * act, uint32_t tid)
+void FuncNode::update_predicate_tree(action_list_t * act_list)
 {
-       ASSERT(act);
+       if (act_list == NULL || act_list->size() == 0)
+               return;
+
+       incr_marker();
+
+       /* Map a FuncInst to the its predicate */
+       HashTable<FuncInst *, Predicate *, uintptr_t, 0> inst_pred_map(128);
+
+       // Number FuncInsts to detect loops
+       HashTable<FuncInst *, uint32_t, uintptr_t, 0> inst_id_map(128);
+       uint32_t inst_counter = 0;
+
+       /* Only need to store the locations of read actions */
+       HashTable<void *, ModelAction *, uintptr_t, 0> loc_act_map(128);
+
+       sllnode<ModelAction *> *it = act_list->begin();
+       Predicate * curr_pred = predicate_tree_entry;
+       while (it != NULL) {
+               ModelAction * next_act = it->getVal();
+               FuncInst * next_inst = get_inst(next_act);
+               next_inst->set_associated_act(next_act, marker);
+
+               SnapVector<Predicate *> unset_predicates = SnapVector<Predicate *>();
+               bool branch_found = follow_branch(&curr_pred, next_inst, next_act, &unset_predicates);
+
+               // A branch with unset predicate expression is detected
+               if (!branch_found && unset_predicates.size() != 0) {
+                       ASSERT(unset_predicates.size() == 1);
+                       Predicate * one_branch = unset_predicates[0];
+
+                       bool amended = amend_predicate_expr(&curr_pred, next_inst, next_act);
+                       if (amended)
+                               continue;
+                       else {
+                               curr_pred = one_branch;
+                               branch_found = true;
+                       }
+               }
+
+               // Detect loops
+               if (!branch_found && inst_id_map.contains(next_inst)) {
+                       FuncInst * curr_inst = curr_pred->get_func_inst();
+                       uint32_t curr_id = inst_id_map.get(curr_inst);
+                       uint32_t next_id = inst_id_map.get(next_inst);
+
+                       if (curr_id >= next_id) {
+                               Predicate * old_pred = inst_pred_map.get(next_inst);
+                               Predicate * back_pred = old_pred->get_parent();
+
+                               curr_pred->add_backedge(back_pred);
+                               curr_pred = back_pred;
+                               continue;
+                       }
+               }
+
+               // Generate new branches
+               if (!branch_found) {
+                       SnapVector<struct half_pred_expr *> half_pred_expressions;
+                       infer_predicates(next_inst, next_act, &loc_act_map, &half_pred_expressions);
+                       generate_predicates(&curr_pred, next_inst, &half_pred_expressions);
+                       continue;
+               }
+
+               if (next_act->is_write())
+                       curr_pred->set_write(true);
+
+               if (next_act->is_read()) {
+                       loc_act_map.put(next_act->get_location(), next_act);
+               }
+
+               inst_pred_map.put(next_inst, curr_pred);
+               if (!inst_id_map.contains(next_inst))
+                       inst_id_map.put(next_inst, inst_counter++);
+
+               it = it->getNext();
+               curr_pred->incr_expl_count();
+       }
+
+       curr_pred->set_exit(predicate_tree_exit);
+}
+
+/* Given curr_pred and next_inst, find the branch following curr_pred that
+ * contains next_inst and the correct predicate. 
+ * @return true if branch found, false otherwise.
+ */
+bool FuncNode::follow_branch(Predicate ** curr_pred, FuncInst * next_inst,
+       ModelAction * next_act, SnapVector<Predicate *> * unset_predicates)
+{
+       /* Check if a branch with func_inst and corresponding predicate exists */
+       bool branch_found = false;
+       ModelVector<Predicate *> * branches = (*curr_pred)->get_children();
+       for (uint i = 0; i < branches->size(); i++) {
+               Predicate * branch = (*branches)[i];
+               if (branch->get_func_inst() != next_inst)
+                       continue;
+
+               /* Check against predicate expressions */
+               bool predicate_correct = true;
+               PredExprSet * pred_expressions = branch->get_pred_expressions();
+               PredExprSetIter * pred_expr_it = pred_expressions->iterator();
+
+               /* Only read and rmw actions my have unset predicate expressions */
+               if (pred_expressions->getSize() == 0) {
+                       predicate_correct = false;
+                       unset_predicates->push_back(branch);
+               }
+
+               while (pred_expr_it->hasNext()) {
+                       pred_expr * pred_expression = pred_expr_it->next();
+                       uint64_t last_read, next_read;
+                       bool equality;
+
+                       switch(pred_expression->token) {
+                               case NOPREDICATE:
+                                       predicate_correct = true;
+                                       break;
+                               case EQUALITY:
+                                       FuncInst * to_be_compared;
+                                       ModelAction * last_act;
+
+                                       to_be_compared = pred_expression->func_inst;
+                                       last_act = to_be_compared->get_associated_act(marker);
+
+                                       last_read = last_act->get_reads_from_value();
+                                       next_read = next_act->get_reads_from_value();
+                                       equality = (last_read == next_read);
+                                       if (equality != pred_expression->value)
+                                               predicate_correct = false;
+
+                                       break;
+                               case NULLITY:
+                                       next_read = next_act->get_reads_from_value();
+                                       equality = ((void*)next_read == NULL);
+                                       if (equality != pred_expression->value)
+                                               predicate_correct = false;
+                                       break;
+                               default:
+                                       predicate_correct = false;
+                                       model_print("unkown predicate token\n");
+                                       break;
+                       }
+               }
+
+               if (predicate_correct) {
+                       *curr_pred = branch;
+                       branch_found = true;
+                       break;
+               }
+       }
 
-       void * location = act->get_location();
-       uint64_t read_from_val = act->get_reads_from_value();
+       return branch_found;
+}
+
+/* Infer predicate expressions, which are generated in FuncNode::generate_predicates */
+void FuncNode::infer_predicates(FuncInst * next_inst, ModelAction * next_act,
+       HashTable<void *, ModelAction *, uintptr_t, 0> * loc_act_map,
+       SnapVector<struct half_pred_expr *> * half_pred_expressions)
+{
+       void * loc = next_act->get_location();
+
+       if (next_inst->is_read()) {
+               /* read + rmw */
+               if ( loc_act_map->contains(loc) ) {
+                       ModelAction * last_act = loc_act_map->get(loc);
+                       FuncInst * last_inst = get_inst(last_act);
+                       struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
+                       half_pred_expressions->push_back(expression);
+               } else if ( next_inst->is_single_location() ){
+                       loc_set_t * loc_may_equal = loc_may_equal_map->get(loc);
+
+                       if (loc_may_equal != NULL) {
+                               loc_set_iter * loc_it = loc_may_equal->iterator();
+                               while (loc_it->hasNext()) {
+                                       void * neighbor = loc_it->next();
+                                       if (loc_act_map->contains(neighbor)) {
+                                               ModelAction * last_act = loc_act_map->get(neighbor);
+                                               FuncInst * last_inst = get_inst(last_act);
+
+                                               struct half_pred_expr * expression = new half_pred_expr(EQUALITY, last_inst);
+                                               half_pred_expressions->push_back(expression);
+                                       }
+                               }
+                       }
+               } else {
+                       // next_inst is not single location
+                       uint64_t read_val = next_act->get_reads_from_value();
+
+                       // only infer NULLITY predicate when it is actually NULL.
+                       if ( (void*)read_val == NULL) {
+                               struct half_pred_expr * expression = new half_pred_expr(NULLITY, NULL);
+                               half_pred_expressions->push_back(expression);
+                       }
+               }
+       } else {
+               /* Pure writes */
+               // TODO: do anything here?
+       }
+}
+
+/* Able to generate complex predicates when there are multiple predciate expressions */
+void FuncNode::generate_predicates(Predicate ** curr_pred, FuncInst * next_inst,
+       SnapVector<struct half_pred_expr *> * half_pred_expressions)
+{
+       if (half_pred_expressions->size() == 0) {
+               Predicate * new_pred = new Predicate(next_inst);
+               (*curr_pred)->add_child(new_pred);
+               new_pred->set_parent(*curr_pred);
+
+               /* entry predicates and predicates containing pure write actions
+                * have no predicate expressions */
+               if ( (*curr_pred)->is_entry_predicate() )
+                       new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
+               else if (next_inst->is_write()) {
+                       /* next_inst->is_write() <==> pure writes */
+                       new_pred->add_predicate_expr(NOPREDICATE, NULL, true);
+               }
+
+               return;
+       }
+
+       SnapVector<Predicate *> predicates;
+
+       struct half_pred_expr * half_expr = (*half_pred_expressions)[0];
+       predicates.push_back(new Predicate(next_inst));
+       predicates.push_back(new Predicate(next_inst));
+
+       predicates[0]->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
+       predicates[1]->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
+
+       for (uint i = 1; i < half_pred_expressions->size(); i++) {
+               half_expr = (*half_pred_expressions)[i];
+
+               uint old_size = predicates.size();
+               for (uint j = 0; j < old_size; j++) {
+                       Predicate * pred = predicates[j];
+                       Predicate * new_pred = new Predicate(next_inst);
+                       new_pred->copy_predicate_expr(pred);
+
+                       pred->add_predicate_expr(half_expr->token, half_expr->func_inst, true);
+                       new_pred->add_predicate_expr(half_expr->token, half_expr->func_inst, false);
+
+                       predicates.push_back(new_pred);
+               }
+       }
+
+       for (uint i = 0; i < predicates.size(); i++) {
+               Predicate * pred= predicates[i];
+               (*curr_pred)->add_child(pred);
+               pred->set_parent(*curr_pred);
+       }
 
-       /* resize and initialize */
-       uint32_t old_size = thrd_read_map.size();
-       if (old_size <= tid) {
-               thrd_read_map.resize(tid + 1);
-               for (uint32_t i = old_size; i < tid + 1; i++)
-                       thrd_read_map[i] = new read_map_t();
+       /* Free memories allocated by infer_predicate */
+       for (uint i = 0; i < half_pred_expressions->size(); i++) {
+               struct half_pred_expr * tmp = (*half_pred_expressions)[i];
+               snapshot_free(tmp);
        }
+}
+
+/* Amend predicates that contain no predicate expressions. Currenlty only amend with NULLITY predicates */
+bool FuncNode::amend_predicate_expr(Predicate ** curr_pred, FuncInst * next_inst, ModelAction * next_act)
+{
+       // there should only be only child
+       Predicate * unset_pred = (*curr_pred)->get_children()->back();
+       uint64_t read_val = next_act->get_reads_from_value();
+
+       // only generate NULLITY predicate when it is actually NULL.
+       if ( !next_inst->is_single_location() && (void*)read_val == NULL ) {
+               Predicate * new_pred = new Predicate(next_inst);
+
+               (*curr_pred)->add_child(new_pred);
+               new_pred->set_parent(*curr_pred);
 
-       read_map_t * read_map = thrd_read_map[tid];
-       read_map->put(location, read_from_val);
+               unset_pred->add_predicate_expr(NULLITY, NULL, false);
+               new_pred->add_predicate_expr(NULLITY, NULL, true);
 
-       /* Store the memory locations where atomic reads happen */
-       read_locations.add(location);
+               return true;
+       }
+
+       return false;
 }
 
-uint64_t FuncNode::query_last_read(void * location, uint32_t tid)
+void FuncNode::add_to_val_loc_map(uint64_t val, void * loc)
 {
-       if (thrd_read_map.size() <= tid)
-               return 0xdeadbeef;
+       loc_set_t * locations = val_loc_map->get(val);
+
+       if (locations == NULL) {
+               locations = new loc_set_t();
+               val_loc_map->put(val, locations);
+       }
 
-       read_map_t * read_map = thrd_read_map[tid];
+       update_loc_may_equal_map(loc, locations);
+       locations->add(loc);
+       // values_may_read_from->add(val);
+}
 
-       /* last read value not found */
-       if ( !read_map->contains(location) )
-               return 0xdeadbeef;
+void FuncNode::add_to_val_loc_map(value_set_t * values, void * loc)
+{
+       if (values == NULL)
+               return;
 
-       uint64_t read_val = read_map->get(location);
-       return read_val;
+       value_set_iter * it = values->iterator();
+       while (it->hasNext()) {
+               uint64_t val = it->next();
+               add_to_val_loc_map(val, loc);
+       }
 }
 
-/* @param tid thread id
- * Reset read map for a thread. This function shall only be called
- * when a thread exits a function
- */
-void FuncNode::clear_read_map(uint32_t tid)
+void FuncNode::update_loc_may_equal_map(void * new_loc, loc_set_t * old_locations)
 {
-       if (thrd_read_map.size() <= tid)
+       if ( old_locations->contains(new_loc) )
                return;
 
-       thrd_read_map[tid]->reset();
+       loc_set_t * neighbors = loc_may_equal_map->get(new_loc);
+
+       if (neighbors == NULL) {
+               neighbors = new loc_set_t();
+               loc_may_equal_map->put(new_loc, neighbors);
+       }
+
+       loc_set_iter * loc_it = old_locations->iterator();
+       while (loc_it->hasNext()) {
+               // new_loc: { old_locations, ... }
+               void * member = loc_it->next();
+               neighbors->add(member);
+
+               // for each i in old_locations, i : { new_loc, ... }
+               loc_set_t * _neighbors = loc_may_equal_map->get(member);
+               if (_neighbors == NULL) {
+                       _neighbors = new loc_set_t();
+                       loc_may_equal_map->put(member, _neighbors);
+               }
+               _neighbors->add(new_loc);
+       }
+}
+
+/* Every time a thread enters a function, set its position to the predicate tree entry */
+void FuncNode::init_predicate_tree_position(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       if (predicate_tree_position.size() <= (uint) thread_id)
+               predicate_tree_position.resize(thread_id + 1);
+
+       predicate_tree_position[thread_id] = predicate_tree_entry;
 }
 
-void FuncNode::generate_predicate(FuncInst *func_inst)
+void FuncNode::set_predicate_tree_position(thread_id_t tid, Predicate * pred)
 {
-       
+       int thread_id = id_to_int(tid);
+       predicate_tree_position[thread_id] = pred;
 }
 
-/* @param tid thread id
- * Print the values read by the last read actions for each memory location
+/* @return The position of a thread in a predicate tree */
+Predicate * FuncNode::get_predicate_tree_position(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       return predicate_tree_position[thread_id];
+}
+
+/* Make sure elements of thrd_inst_act_map are initialized properly when threads enter functions */
+void FuncNode::init_inst_act_map(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
+       uint old_size = thrd_inst_act_map->size();
+
+       if (thrd_inst_act_map->size() <= (uint) thread_id) {
+               uint new_size = thread_id + 1;
+               thrd_inst_act_map->resize(new_size);
+
+               for (uint i = old_size; i < new_size; i++)
+                       (*thrd_inst_act_map)[i] = new inst_act_map_t(128);
+       }
+}
+
+/* Reset elements of thrd_inst_act_map when threads exit functions */
+void FuncNode::reset_inst_act_map(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
+
+       inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
+       map->reset();
+}
+
+void FuncNode::update_inst_act_map(thread_id_t tid, ModelAction * read_act)
+{
+       int thread_id = id_to_int(tid);
+       SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
+
+       inst_act_map_t * map = (*thrd_inst_act_map)[thread_id];
+       FuncInst * read_inst = get_inst(read_act);
+       map->put(read_inst, read_act);
+}
+
+inst_act_map_t * FuncNode::get_inst_act_map(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       SnapVector<inst_act_map_t *> * thrd_inst_act_map = history->getThrdInstActMap(func_id);
+
+       return (*thrd_inst_act_map)[thread_id];
+}
+
+/* Add FuncNodes that this node may follow */
+void FuncNode::add_out_edge(FuncNode * other)
+{
+       if ( !edge_table.contains(other) ) {
+               edge_table.put(other, OUT_EDGE);
+               out_edges.push_back(other);
+               return;
+       }
+
+       edge_type_t edge = edge_table.get(other);
+       if (edge == IN_EDGE) {
+               edge_table.put(other, BI_EDGE);
+               out_edges.push_back(other);
+       }
+}
+
+/* Compute the distance between this FuncNode and the target node.
+ * Return -1 if the target node is unreachable or the actual distance
+ * is greater than max_step.
  */
-void FuncNode::print_last_read(uint32_t tid)
+int FuncNode::compute_distance(FuncNode * target, int max_step)
 {
-/*
-       ASSERT(thrd_read_map.size() > tid);
-       read_map_t * read_map = thrd_read_map[tid];
+       if (target == NULL)
+               return -1;
+       else if (target == this)
+               return 0;
 
-       ModelList<void *>::iterator it;
-       for (it = read_locations.begin();it != read_locations.end();it++) {
-               if ( !read_map->contains(*it) )
-                       break;
+       SnapList<FuncNode *> queue;
+       HashTable<FuncNode *, int, uintptr_t, 0> distances(128);
 
-               uint64_t read_val = read_map->get(*it);
-               model_print("last read of thread %d at %p: 0x%x\n", tid, *it, read_val);
+       queue.push_back(this);
+       distances.put(this, 0);
+
+       while (!queue.empty()) {
+               FuncNode * curr = queue.front();
+               queue.pop_front();
+               int dist = distances.get(curr);
+
+               if (max_step <= dist)
+                       return -1;
+
+               ModelList<FuncNode *> * outEdges = curr->get_out_edges();
+               mllnode<FuncNode *> * it;
+               for (it = outEdges->begin(); it != NULL; it = it->getNext()) {
+                       FuncNode * out_node = it->getVal();
+
+                       /* This node has not been visited before */
+                       if ( !distances.contains(out_node) ) {
+                               if (out_node == target)
+                                       return dist + 1;
+
+                               queue.push_back(out_node);
+                               distances.put(out_node, dist + 1);
+                       }
+               }
+       }
+
+       /* Target node is unreachable */
+       return -1;
+}
+
+void FuncNode::print_predicate_tree()
+{
+       model_print("digraph function_%s {\n", func_name);
+       predicate_tree_entry->print_pred_subtree();
+       predicate_tree_exit->print_predicate();
+       model_print("}\n");     // end of graph
+}
+
+void FuncNode::print_val_loc_map()
+{
+/*
+       value_set_iter * val_it = values_may_read_from->iterator();
+       while (val_it->hasNext()) {
+               uint64_t value = val_it->next();
+               model_print("val %llx: ", value);
+
+               loc_set_t * locations = val_loc_map->get(value);
+               loc_set_iter * loc_it = locations->iterator();
+               while (loc_it->hasNext()) {
+                       void * location = loc_it->next();
+                       model_print("%p ", location);
+               }
+               model_print("\n");
        }
 */
 }