Every time a thread enters a function, check whether other threads should still wait...
authorweiyu <weiyuluo1232@gmail.com>
Tue, 8 Oct 2019 01:28:20 +0000 (18:28 -0700)
committerweiyu <weiyuluo1232@gmail.com>
Tue, 8 Oct 2019 01:28:20 +0000 (18:28 -0700)
funcnode.cc
history.cc
history.h
newfuzzer.cc
newfuzzer.h
waitobj.cc
waitobj.h

index 18d7771..70cc447 100644 (file)
@@ -646,6 +646,9 @@ void FuncNode::add_out_edge(FuncNode * other)
  */
 int FuncNode::compute_distance(FuncNode * target, int max_step)
 {
+       if (target == NULL)
+               return -1;
+
        SnapList<FuncNode *> queue;
        HashTable<FuncNode *, int, uintptr_t, 0> distances;
 
index 3f098a6..d184fc6 100644 (file)
@@ -28,11 +28,19 @@ ModelHistory::ModelHistory() :
        func_inst_act_maps = new HashTable<uint32_t, SnapVector<inst_act_map_t *> *, int, 0>(128);
 }
 
+ModelHistory::~ModelHistory()
+{
+       // TODO: complete deconstructor
+       for (uint i = 0; i < thrd_wait_obj->size(); )
+               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);
        ModelExecution * execution = model->get_execution();
        uint id = id_to_int(tid);
+
        SnapVector<func_id_list_t> * thrd_func_list = execution->get_thrd_func_list();
        SnapVector< SnapList<action_list_t *> *> *
                thrd_func_act_lists = execution->get_thrd_func_act_lists();
@@ -72,6 +80,8 @@ void ModelHistory::enter_function(const uint32_t func_id, thread_id_t tid)
                FuncNode * last_func_node = func_nodes[last_entered_func_id];
                last_func_node->add_out_edge(func_node);
        }
+
+       monitor_waiting_thread(func_id, tid);
 }
 
 /* @param func_id a non-zero value */
@@ -156,7 +166,7 @@ void ModelHistory::process_action(ModelAction *act, thread_id_t tid)
                uint64_t value = act->get_write_value();
                update_write_history(location, value);
 
-               /* Update FuncNodes that may read from this location */
+               /* 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];
@@ -379,10 +389,10 @@ WaitObj * ModelHistory::getWaitObj(thread_id_t tid)
 }
 
 void ModelHistory::add_waiting_thread(thread_id_t self_id,
-               thread_id_t waiting_for_id, int dist)
+       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, dist);
+       self_wait_obj->add_waiting_for(waiting_for_id, target_node, dist);
 
        /* Update waited-by relation */
        WaitObj * other_wait_obj = getWaitObj(waiting_for_id);
@@ -394,6 +404,7 @@ 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();
@@ -440,6 +451,36 @@ bool ModelHistory::skip_action(ModelAction * act, SnapList<ModelAction *> * curr
        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();
+
+       /* For each thread waiting for tid */
+       thrd_id_set_iter * iter = waited_by->iterator();
+
+       while (iter->hasNext()) {
+               thread_id_t other_id = iter->next();
+               WaitObj * other_wait_obj = getWaitObj(other_id);
+
+               node_set_t * target_nodes = other_wait_obj->getTargetNodes(tid);
+               node_set_iter * iter = target_nodes->iterator();
+               while (iter->hasNext()) {
+                       FuncNode * target = iter->next();
+                       int old_dist = other_wait_obj->lookup_dist(tid, target);
+               }
+               // TODO: Recompute distance from tmp to 'target' nodes
+               // FuncNode * tmp = func_nodes[func_id];
+       }
+}
+
 /* Reallocate some snapshotted memories when new executions start */
 void ModelHistory::set_new_exec_flag()
 {
index a718510..82a1a01 100644 (file)
--- a/history.h
+++ b/history.h
@@ -40,7 +40,7 @@ public:
        SnapVector<ConcretePredicate *> * getThrdWaitingWrite() { return thrd_waiting_write; }
 
        WaitObj * getWaitObj(thread_id_t tid);
-       void add_waiting_thread(thread_id_t self_id, thread_id_t waiting_for_id, int dist);
+       void add_waiting_thread(thread_id_t self_id, thread_id_t waiting_for_id, FuncNode * target_node, int dist);
        void remove_waiting_thread(thread_id_t tid);
 
        SnapVector<inst_act_map_t *> * getThrdInstActMap(uint32_t func_id);
@@ -76,11 +76,12 @@ private:
        SnapVector<ConcretePredicate *> * thrd_waiting_write;
        SnapVector<WaitObj *> * thrd_wait_obj;
 
-       /* A run-time map from FuncInst to ModelAction per each thread, per each FuncNode.
+       /* A run-time map from FuncInst to ModelAction per thread, per FuncNode.
         * Manipulated by FuncNode, and needed by NewFuzzer */
        HashTable<uint32_t, SnapVector<inst_act_map_t *> *, int, 0> * func_inst_act_maps;
 
        bool skip_action(ModelAction * act, SnapList<ModelAction *> * curr_act_list);
+       void monitor_waiting_thread(uint32_t func_id, thread_id_t tid);
 };
 
 #endif /* __HISTORY_H__ */
index b5f1cd8..6810d02 100644 (file)
@@ -17,7 +17,7 @@ NewFuzzer::NewFuzzer() :
        thrd_curr_pred(),
        thrd_selected_child_branch(),
        thrd_pruned_writes(),
-       paused_thread_set(),
+       paused_thread_list(),
        paused_thread_table(128)
 {}
 
@@ -210,10 +210,10 @@ bool NewFuzzer::prune_writes(thread_id_t tid, Predicate * pred,
  */
 void NewFuzzer::conditional_sleep(Thread * thread)
 {
-       int index = paused_thread_set.size();
+       int index = paused_thread_list.size();
 
        model->getScheduler()->add_sleep(thread);
-       paused_thread_set.push_back(thread);
+       paused_thread_list.push_back(thread);
        paused_thread_table.put(thread, index); // Update table
 
        /* Add the waiting condition to ModelHistory */
@@ -234,7 +234,7 @@ void NewFuzzer::conditional_sleep(Thread * thread)
 
 bool NewFuzzer::has_paused_threads()
 {
-       return paused_thread_set.size() != 0;
+       return paused_thread_list.size() != 0;
 }
 
 Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
@@ -255,13 +255,13 @@ Thread * NewFuzzer::selectThread(int * threadlist, int numthreads)
  */
 void NewFuzzer::wake_up_paused_threads(int * threadlist, int * numthreads)
 {
-       int random_index = random() % paused_thread_set.size();
-       Thread * thread = paused_thread_set[random_index];
+       int random_index = random() % paused_thread_list.size();
+       Thread * thread = paused_thread_list[random_index];
        model->getScheduler()->remove_sleep(thread);
 
-       Thread * last_thread = paused_thread_set.back();
-       paused_thread_set[random_index] = last_thread;
-       paused_thread_set.pop_back();
+       Thread * last_thread = paused_thread_list.back();
+       paused_thread_list[random_index] = last_thread;
+       paused_thread_list.pop_back();
        paused_thread_table.put(last_thread, random_index);     // Update table
        paused_thread_table.remove(thread);
 
@@ -282,9 +282,9 @@ void NewFuzzer::notify_paused_thread(Thread * thread)
        int index = paused_thread_table.get(thread);
        model->getScheduler()->remove_sleep(thread);
 
-       Thread * last_thread = paused_thread_set.back();
-       paused_thread_set[index] = last_thread;
-       paused_thread_set.pop_back();
+       Thread * last_thread = paused_thread_list.back();
+       paused_thread_list[index] = last_thread;
+       paused_thread_list.pop_back();
        paused_thread_table.put(last_thread, index);    // Update table
        paused_thread_table.remove(thread);
 
@@ -316,7 +316,7 @@ void NewFuzzer::find_threads(ModelAction * pending_read)
 
                        int distance = node->compute_distance(target_node);
                        if (distance != -1) {
-                               history->add_waiting_thread(self_id, tid, distance);
+                               history->add_waiting_thread(self_id, tid, target_node, distance);
                                model_print("thread: %d; distance from node %d to node %d: %d\n", tid, node->get_func_id(), target_node->get_func_id(), distance);
 
                        }
index 0e5d483..6ce1e7f 100644 (file)
@@ -37,7 +37,7 @@ private:
 
        /* The set of Threads put to sleep by NewFuzzer because no writes in rf_set satisfies the selected predicate. Only used by selectWrite.
         */
-       SnapVector<Thread *> paused_thread_set;
+       SnapVector<Thread *> paused_thread_list;
        HashTable<Thread *, int, uintptr_t, 0> paused_thread_table;
 
        void conditional_sleep(Thread * thread);
index 3aaa632..64def5a 100644 (file)
@@ -1,16 +1,32 @@
 #include "waitobj.h"
+#include "threads-model.h"
 
 WaitObj::WaitObj(thread_id_t tid) :
        tid(tid),
        waiting_for(32),
        waited_by(32),
-       dist_table(32)
+       thrd_dist_maps(),
+       thrd_target_nodes()
 {}
 
-void WaitObj::add_waiting_for(thread_id_t other, int dist)
+WaitObj::~WaitObj()
+{
+       for (uint i = 0; i < thrd_dist_maps.size(); i++)
+               delete thrd_dist_maps[i];
+
+       for (uint i = 0; i < thrd_target_nodes.size(); i++)
+               delete thrd_target_nodes[i];
+}
+
+void WaitObj::add_waiting_for(thread_id_t other, FuncNode * node, int dist)
 {
        waiting_for.add(other);
-       dist_table.put(other, dist);
+
+       dist_map_t * dist_map = getDistMap(other);
+       dist_map->put(node, dist);
+
+       node_set_t * target_nodes = getTargetNodes(other);
+       target_nodes->add(node);
 }
 
 void WaitObj::add_waited_by(thread_id_t other)
@@ -18,10 +34,28 @@ void WaitObj::add_waited_by(thread_id_t other)
        waited_by.add(other);
 }
 
-void WaitObj::remove_waiting_for(thread_id_t other)
+/**
+ * Stop waiting for the thread to reach the target node
+ *
+ * @param other The thread to be removed
+ * @param node The target node
+ * @return true if "other" is removed from waiting_for set
+ */
+bool WaitObj::remove_waiting_for(thread_id_t other, FuncNode * node)
 {
-       waiting_for.remove(other);
-       dist_table.remove(other);
+       dist_map_t * dist_map = getDistMap(other);
+       dist_map->remove(node);
+
+       node_set_t * target_nodes = getTargetNodes(other);
+       target_nodes->remove(node);
+
+       /* The thread has not nodes to reach */
+       if (target_nodes->isEmpty()) {
+               waiting_for.remove(other);
+               return true;
+       }
+
+       return false;
 }
 
 void WaitObj::remove_waited_by(thread_id_t other)
@@ -29,19 +63,58 @@ void WaitObj::remove_waited_by(thread_id_t other)
        waited_by.remove(other);
 }
 
-int WaitObj::lookup_dist(thread_id_t other_id)
+int WaitObj::lookup_dist(thread_id_t tid, FuncNode * target)
 {
-       if (dist_table.contains(other_id))
-               return dist_table.get(other_id);
+       dist_map_t * map = getDistMap(tid);
+       if (map->contains(target))
+               return map->get(target);
 
        return -1;
 }
 
+dist_map_t * WaitObj::getDistMap(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       int old_size = thrd_dist_maps.size();
+
+       if (old_size <= thread_id) {
+               thrd_dist_maps.resize(thread_id + 1);
+               for (int i = old_size; i < thread_id + 1; i++) {
+                       thrd_dist_maps[i] = new dist_map_t(16);
+               }
+       }
+
+       return thrd_dist_maps[thread_id];
+}
+
+node_set_t * WaitObj::getTargetNodes(thread_id_t tid)
+{
+       int thread_id = id_to_int(tid);
+       int old_size = thrd_target_nodes.size();
+
+       if (old_size <= thread_id) {
+               thrd_target_nodes.resize(thread_id + 1);
+               for (int i = old_size; i < thread_id + 1; i++) {
+                       thrd_target_nodes[i] = new node_set_t(16);
+               }
+       }
+
+       return thrd_target_nodes[thread_id];
+}
+
 void WaitObj::reset()
 {
+       thrd_id_set_iter * iter = waiting_for.iterator();
+       while (iter->hasNext()) {
+               thread_id_t tid = iter->next();
+               int index = id_to_int(tid);
+               thrd_target_nodes[index]->reset();
+               /* thrd_dist_maps are not reset because distances
+                * will be overwritten */
+       }
+
        waiting_for.reset();
        waited_by.reset();
-       dist_table.reset();
 }
 
 void WaitObj::print_waiting_for()
index ae7a5fe..9b4aead 100644 (file)
--- a/waitobj.h
+++ b/waitobj.h
@@ -4,22 +4,28 @@
 #include "classlist.h"
 #include "modeltypes.h"
 
+typedef HashTable<FuncNode *, int, uintptr_t, 0> dist_map_t;
+typedef HashSet<FuncNode *, uintptr_t, 0> node_set_t;
+typedef HSIterator<FuncNode *, uintptr_t, 0> node_set_iter;
+
 class WaitObj {
 public:
        WaitObj(thread_id_t);
-       ~WaitObj() {}
+       ~WaitObj();
 
        thread_id_t get_tid() { return tid; }
 
-       void add_waiting_for(thread_id_t other, int dist);
+       void add_waiting_for(thread_id_t other, FuncNode * node, int dist);
        void add_waited_by(thread_id_t other);
-       void remove_waiting_for(thread_id_t other);
+       bool remove_waiting_for(thread_id_t other, FuncNode * node);
        void remove_waited_by(thread_id_t other);
 
        thrd_id_set_t * getWaitingFor() { return &waiting_for; }
-       thrd_id_set_t * getWaitingBy() { return &waited_by; }
-       int lookup_dist(thread_id_t other_tid);
+       thrd_id_set_t * getWaitedBy() { return &waited_by; }
 
+       node_set_t * getTargetNodes(thread_id_t tid);
+       int lookup_dist(thread_id_t tid, FuncNode * target);
+       int lookup_dist(thread_id_t other_tid);
        void reset();
 
        void print_waiting_for();
@@ -35,7 +41,10 @@ private:
        /* The set of threads waiting for this thread */
        thrd_id_set_t waited_by;
 
-       HashTable<thread_id_t, int, int, 0> dist_table;
+       SnapVector<dist_map_t *> thrd_dist_maps;
+       SnapVector<node_set_t *> thrd_target_nodes;
+
+       dist_map_t * getDistMap(thread_id_t tid);
 };
 
 #endif