fix sleeping bug
[c11tester.git] / model.cc
index 69df0d226023ec9b212e55e5276c2993c2d001cb..d3692c47c80c5731cc32e9bddc920aa5a7d8bdad 100644 (file)
--- a/model.cc
+++ b/model.cc
 #include "history.h"
 #include "bugmessage.h"
 #include "params.h"
+#include "plugins.h"
 
 ModelChecker *model = NULL;
 
+void placeholder(void *) {
+       ASSERT(0);
+}
+
 /** @brief Constructor */
 ModelChecker::ModelChecker() :
        /* Initialize default scheduler */
        params(),
-       restart_flag(false),
        scheduler(new Scheduler()),
        history(new ModelHistory()),
        execution(new ModelExecution(this, scheduler)),
@@ -33,12 +37,12 @@ ModelChecker::ModelChecker() :
        trace_analyses(),
        inspect_plugin(NULL)
 {
-       printf("C11Tester\n"
-              "Copyright (c) 2013 and 2019 Regents of the University of California. All rights reserved.\n"
-              "Distributed under the GPLv2\n"
-              "Written by Weiyu Luo, Brian Norris, and Brian Demsky\n\n");
+       model_print("C11Tester\n"
+                                                       "Copyright (c) 2013 and 2019 Regents of the University of California. All rights reserved.\n"
+                                                       "Distributed under the GPLv2\n"
+                                                       "Written by Weiyu Luo, Brian Norris, and Brian Demsky\n\n");
        memset(&stats,0,sizeof(struct execution_stats));
-       init_thread = new Thread(execution->get_next_id(), (thrd_t *) model_malloc(sizeof(thrd_t)), NULL, NULL, NULL);
+       init_thread = new Thread(execution->get_next_id(), (thrd_t *) model_malloc(sizeof(thrd_t)), &placeholder, NULL, NULL);
 #ifdef TLS
        init_thread->setTLS((char *)get_tls_addr());
 #endif
@@ -51,7 +55,7 @@ ModelChecker::ModelChecker() :
        initRaceDetector();
        /* Configure output redirection for the model-checker */
        redirect_output();
-       install_trace_analyses(model->get_execution());
+       install_trace_analyses(get_execution());
 }
 
 /** @brief Destructor */
@@ -80,7 +84,7 @@ void ModelChecker::reset_to_initial_state()
        for (unsigned int i = 0;i < get_num_threads();i++)
                delete get_thread(int_to_id(i))->get_pending();
 
-       snapshot_backtrack_before(0);
+       snapshot_roll_back(snapshot);
 }
 
 /** @return the number of user threads created during this execution */
@@ -232,7 +236,7 @@ void ModelChecker::print_execution(bool printbugs) const
  * @return If there are more executions to explore, return true. Otherwise,
  * return false.
  */
-bool ModelChecker::next_execution()
+void ModelChecker::finish_execution(bool more_executions)
 {
        DBG();
        /* Is this execution a feasible execution that's worth bug-checking? */
@@ -254,15 +258,11 @@ bool ModelChecker::next_execution()
        else
                clear_program_output();
 
-       if (restart_flag) {
-               do_restart();
-               return true;
-       }
 // test code
        execution_number ++;
-       reset_to_initial_state();
+       if (more_executions)
+               reset_to_initial_state();
        history->set_new_exec_flag();
-       return false;
 }
 
 /** @brief Run trace analyses on complete trace */
@@ -344,6 +344,164 @@ uint64_t ModelChecker::switch_to_master(ModelAction *act)
        return old->get_return_value();
 }
 
+void ModelChecker::continueExecution(Thread *old) 
+{
+       if (params.traceminsize != 0 &&
+                       execution->get_curr_seq_num() > checkfree) {
+               checkfree += params.checkthreshold;
+               execution->collectActions();
+       }
+       thread_chosen = false;
+       curr_thread_num = 1;
+       Thread *thr = getNextThread();
+       if (thr != nullptr) {
+               scheduler->set_current_thread(thr);
+               if (Thread::swap(old, thr) < 0) {
+                       perror("swap threads");
+                       exit(EXIT_FAILURE);
+               }
+       } else
+               handleChosenThread(old);        
+}
+
+Thread* ModelChecker::getNextThread()
+{
+       Thread *thr = nullptr;
+       for (unsigned int i = curr_thread_num; i < get_num_threads(); i++) {
+               thread_id_t tid = int_to_id(i);
+               thr = get_thread(tid);
+               
+               if (!thr->is_complete() && !thr->get_pending()) {
+                       curr_thread_num = i;
+                       break;
+               }
+               ModelAction *act = thr->get_pending();
+               
+               if (act && execution->is_enabled(thr) && !execution->check_action_enabled(act)) {
+                       scheduler->sleep(thr);
+               }
+
+               chooseThread(act, thr);
+       }
+       return thr;
+}
+
+void ModelChecker::finishExecution(Thread *old) 
+{
+       scheduler->set_current_thread(NULL);
+       if (Thread::swap(old, &system_context) < 0) {
+               perror("swap threads");
+               exit(EXIT_FAILURE);
+       }
+}
+
+void ModelChecker::consumeAction()
+{
+       ModelAction *curr = chosen_thread->get_pending();
+       chosen_thread->set_pending(NULL);
+       chosen_thread = execution->take_step(curr);
+}
+
+void ModelChecker::chooseThread(ModelAction *act, Thread *old)
+{
+       if (!thread_chosen && act && execution->is_enabled(old) && (old->get_state() != THREAD_BLOCKED) ) {
+               if (act->is_write()) {
+                       std::memory_order order = act->get_mo();
+                       if (order == std::memory_order_relaxed || \
+                                       order == std::memory_order_release) {
+                               chosen_thread = old;
+                               thread_chosen = true;
+                       }
+               } else if (act->get_type() == THREAD_CREATE || \
+                                                       act->get_type() == PTHREAD_CREATE || \
+                                                       act->get_type() == THREAD_START || \
+                                                       act->get_type() == THREAD_FINISH) {
+                       chosen_thread = old;
+                       thread_chosen = true;
+               }
+       }       
+}
+
+uint64_t ModelChecker::switch_thread(ModelAction *act)
+{
+       if (modellock) {
+               static bool fork_message_printed = false;
+
+               if (!fork_message_printed) {
+                       model_print("Fork handler or dead thread trying to call into model checker...\n");
+                       fork_message_printed = true;
+               }
+               delete act;
+               return 0;
+       }
+       DBG();
+       Thread *old = thread_current();
+       ASSERT(!old->get_pending());
+
+       if (inspect_plugin != NULL) {
+               inspect_plugin->inspectModelAction(act);
+       }
+
+       old->set_pending(act);
+
+       curr_thread_num++;
+       Thread* next = getNextThread();
+       if (next != nullptr) 
+               handleNewValidThread(old, next);
+       else
+               handleChosenThread(old);
+
+       return old->get_return_value();
+}
+
+void ModelChecker::handleNewValidThread(Thread *old, Thread *next)
+{
+       if (old->is_waiting_on(old))
+               assert_bug("Deadlock detected (thread %u)", curr_thread_num-1);
+
+       ModelAction *act = old->get_pending();
+               
+       if (act && execution->is_enabled(old) && !execution->check_action_enabled(act)) {
+               scheduler->sleep(old);
+       }
+       chooseThread(act, old);
+
+       scheduler->set_current_thread(next);    
+
+       if (Thread::swap(old, next) < 0) {
+               perror("swap threads");
+               exit(EXIT_FAILURE);
+       }               
+}
+
+void ModelChecker::handleChosenThread(Thread *old)
+{
+       if (execution->has_asserted())
+               finishExecution(old);
+       if (!chosen_thread)
+               chosen_thread = get_next_thread();
+       if (!chosen_thread || chosen_thread->is_model_thread())
+               finishExecution(old);
+       if (chosen_thread->just_woken_up()) {
+               chosen_thread->set_wakeup_state(false);
+               chosen_thread->set_pending(NULL);
+               chosen_thread = NULL;
+               // Allow this thread to stash the next pending action
+               if (should_terminate_execution())
+                       finishExecution(old);
+               else
+                       continueExecution(old); 
+       } else {
+               /* Consume the next action for a Thread */
+               consumeAction();
+
+               if (should_terminate_execution())
+                       finishExecution(old);
+               else
+                       continueExecution(old);         
+       }
+}
+
 static void runChecker() {
        model->run();
        delete model;
@@ -351,8 +509,8 @@ static void runChecker() {
 
 void ModelChecker::startChecker() {
        startExecution(get_system_context(), runChecker);
-       snapshot_stack_init();
-       snapshot_record(0);
+       snapshot = take_snapshot();
+       initMainThread();
 }
 
 bool ModelChecker::should_terminate_execution()
@@ -366,106 +524,21 @@ bool ModelChecker::should_terminate_execution()
        return false;
 }
 
-/** @brief Restart ModelChecker upon returning to the run loop of the
- *     model checker. */
-void ModelChecker::restart()
-{
-       restart_flag = true;
-}
-
-void ModelChecker::do_restart()
-{
-       restart_flag = false;
-       reset_to_initial_state();
-       memset(&stats,0,sizeof(struct execution_stats));
-       execution_number = 1;
-}
-
-void ModelChecker::startMainThread() {
-       init_thread->set_state(THREAD_RUNNING);
-       scheduler->set_current_thread(init_thread);
-       main_thread_startup();
-}
-
 /** @brief Run ModelChecker for the user program */
 void ModelChecker::run()
 {
        //Need to initial random number generator state to avoid resets on rollback
        char random_state[256];
        initstate(423121, random_state, sizeof(random_state));
-
+       checkfree = params.checkthreshold;
        for(int exec = 0;exec < params.maxexecutions;exec++) {
-               Thread * t = init_thread;
-
-               do {
-                       /*
-                        * Stash next pending action(s) for thread(s). There
-                        * should only need to stash one thread's action--the
-                        * thread which just took a step--plus the first step
-                        * for any newly-created thread
-                        */
-                       for (unsigned int i = 0;i < get_num_threads();i++) {
-                               thread_id_t tid = int_to_id(i);
-                               Thread *thr = get_thread(tid);
-                               if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) {
-                                       switch_from_master(thr);
-                                       if (thr->is_waiting_on(thr))
-                                               assert_bug("Deadlock detected (thread %u)", i);
-                               }
-                       }
-
-                       /* Don't schedule threads which should be disabled */
-                       for (unsigned int i = 0;i < get_num_threads();i++) {
-                               Thread *th = get_thread(int_to_id(i));
-                               ModelAction *act = th->get_pending();
-                               if (act && execution->is_enabled(th) && !execution->check_action_enabled(act)) {
-                                       scheduler->sleep(th);
-                               }
-                       }
-
-                       for (unsigned int i = 1;i < get_num_threads();i++) {
-                               Thread *th = get_thread(int_to_id(i));
-                               ModelAction *act = th->get_pending();
-                               if (act && execution->is_enabled(th) && (th->get_state() != THREAD_BLOCKED) ) {
-                                       if (act->is_write()) {
-                                               std::memory_order order = act->get_mo();
-                                               if (order == std::memory_order_relaxed || \
-                                                               order == std::memory_order_release) {
-                                                       t = th;
-                                                       break;
-                                               }
-                                       } else if (act->get_type() == THREAD_CREATE || \
-                                                                                act->get_type() == PTHREAD_CREATE || \
-                                                                                act->get_type() == THREAD_START || \
-                                                                                act->get_type() == THREAD_FINISH) {
-                                               t = th;
-                                               break;
-                                       }
-                               }
-                       }
-
-                       /* Catch assertions from prior take_step or from
-                       * between-ModelAction bugs (e.g., data races) */
-
-                       if (execution->has_asserted())
-                               break;
-                       if (!t)
-                               t = get_next_thread();
-                       if (!t || t->is_model_thread())
-                               break;
-                       if (t->just_woken_up()) {
-                               t->set_wakeup_state(false);
-                               t->set_pending(NULL);
-                               t = NULL;
-                               continue;       // Allow this thread to stash the next pending action
-                       }
-
-                       /* Consume the next action for a Thread */
-                       ModelAction *curr = t->get_pending();
-                       t->set_pending(NULL);
-                       t = execution->take_step(curr);
-               } while (!should_terminate_execution());
-               next_execution();
+               chosen_thread = init_thread;
+               thread_chosen = false;
+               curr_thread_num = 1;
+               thread_id_t tid = int_to_id(1);
+               Thread *thr = get_thread(tid);
+               switch_from_master(thr);
+               finish_execution((exec+1) < params.maxexecutions);
                //restore random number generator state after rollback
                setstate(random_state);
        }