Add some debug support code
[c11tester.git] / model.cc
index 230607a0137c957ab475ae0aee3d32f960e231c1..5b5ccf701c1798f9627c352f6ae50be4159fc929 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -2,10 +2,11 @@
 #include <algorithm>
 #include <new>
 #include <stdarg.h>
+#include <string.h>
+#include <cstdlib>
 
 #include "model.h"
 #include "action.h"
-#include "nodestack.h"
 #include "schedule.h"
 #include "snapshot-interface.h"
 #include "common.h"
 #include "output.h"
 #include "traceanalysis.h"
 #include "execution.h"
+#include "history.h"
 #include "bugmessage.h"
+#include "params.h"
+#include "plugins.h"
 
-ModelChecker *model;
+ModelChecker *model = NULL;
+
+void placeholder(void *) {
+       ASSERT(0);
+}
+
+#include <signal.h>
+
+#define SIGSTACKSIZE 65536
+static void mprot_handle_pf(int sig, siginfo_t *si, void *unused)
+{
+       model_print("Segmentation fault at %p\n", si->si_addr);
+       model_print("For debugging, place breakpoint at: %s:%d\n",
+                                                       __FILE__, __LINE__);
+       print_trace();  // Trace printing may cause dynamic memory allocation
+       while(1)
+               ;
+}
+
+void install_handler() {
+       stack_t ss;
+       ss.ss_sp = model_malloc(SIGSTACKSIZE);
+       ss.ss_size = SIGSTACKSIZE;
+       ss.ss_flags = 0;
+       sigaltstack(&ss, NULL);
+       struct sigaction sa;
+       sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART | SA_ONSTACK;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_sigaction = mprot_handle_pf;
+
+       if (sigaction(SIGSEGV, &sa, NULL) == -1) {
+               perror("sigaction(SIGSEGV)");
+               exit(EXIT_FAILURE);
+       }
+
+}
 
 /** @brief Constructor */
-ModelChecker::ModelChecker(struct model_params params) :
+ModelChecker::ModelChecker() :
        /* Initialize default scheduler */
-       params(params),
+       params(),
        scheduler(new Scheduler()),
-       node_stack(new NodeStack()),
-       execution(new ModelExecution(this, &this->params, scheduler, node_stack)),
+       history(new ModelHistory()),
+       execution(new ModelExecution(this, scheduler)),
        execution_number(1),
-       diverge(NULL),
-       earliest_diverge(NULL),
-       trace_analyses()
+       trace_analyses(),
+       inspect_plugin(NULL)
 {
+       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)), &placeholder, NULL, NULL);
+#ifdef TLS
+       init_thread->setTLS((char *)get_tls_addr());
+#endif
+       execution->add_thread(init_thread);
+       scheduler->set_current_thread(init_thread);
+       register_plugins();
+       execution->setParams(&params);
+       param_defaults(&params);
+       parse_options(&params);
+       initRaceDetector();
+       /* Configure output redirection for the model-checker */
+       redirect_output();
+       install_trace_analyses(get_execution());
+       install_handler();
 }
 
 /** @brief Destructor */
 ModelChecker::~ModelChecker()
 {
-       delete node_stack;
        delete scheduler;
 }
 
+/** Method to set parameters */
+model_params * ModelChecker::getParams() {
+       return &params;
+}
+
 /**
  * Restores user program to initial state and resets all model-checker data
  * structures.
  */
 void ModelChecker::reset_to_initial_state()
 {
-       DEBUG("+++ Resetting to initial state +++\n");
-       node_stack->reset_execution();
 
        /**
         * FIXME: if we utilize partial rollback, we will need to free only
         * those pending actions which were NOT pending before the rollback
         * point
         */
-       for (unsigned int i = 0; i < get_num_threads(); i++)
+       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 */
@@ -89,73 +149,12 @@ Thread * ModelChecker::get_current_thread() const
  */
 Thread * ModelChecker::get_next_thread()
 {
-       thread_id_t tid;
 
        /*
         * Have we completed exploring the preselected path? Then let the
         * scheduler decide
         */
-       if (diverge == NULL)
-               return scheduler->select_next_thread(node_stack->get_head());
-
-
-       /* Else, we are trying to replay an execution */
-       ModelAction *next = node_stack->get_next()->get_action();
-
-       if (next == diverge) {
-               if (earliest_diverge == NULL || *diverge < *earliest_diverge)
-                       earliest_diverge = diverge;
-
-               Node *nextnode = next->get_node();
-               Node *prevnode = nextnode->get_parent();
-               scheduler->update_sleep_set(prevnode);
-
-               /* Reached divergence point */
-               if (nextnode->increment_behaviors()) {
-                       /* Execute the same thread with a new behavior */
-                       tid = next->get_tid();
-                       node_stack->pop_restofstack(2);
-               } else {
-                       ASSERT(prevnode);
-                       /* Make a different thread execute for next step */
-                       scheduler->add_sleep(get_thread(next->get_tid()));
-                       tid = prevnode->get_next_backtrack();
-                       /* Make sure the backtracked thread isn't sleeping. */
-                       node_stack->pop_restofstack(1);
-                       if (diverge == earliest_diverge) {
-                               earliest_diverge = prevnode->get_action();
-                       }
-               }
-               /* Start the round robin scheduler from this thread id */
-               scheduler->set_scheduler_thread(tid);
-               /* The correct sleep set is in the parent node. */
-               execute_sleep_set();
-
-               DEBUG("*** Divergence point ***\n");
-
-               diverge = NULL;
-       } else {
-               tid = next->get_tid();
-       }
-       DEBUG("*** ModelChecker chose next thread = %d ***\n", id_to_int(tid));
-       ASSERT(tid != THREAD_ID_T_NONE);
-       return get_thread(id_to_int(tid));
-}
-
-/**
- * We need to know what the next actions of all threads in the sleep
- * set will be.  This method computes them and stores the actions at
- * the corresponding thread object's pending action.
- */
-void ModelChecker::execute_sleep_set()
-{
-       for (unsigned int i = 0; i < get_num_threads(); i++) {
-               thread_id_t tid = int_to_id(i);
-               Thread *thr = get_thread(tid);
-               if (scheduler->is_sleep_set(thr) && thr->get_pending()) {
-                       thr->get_pending()->set_sleep_flag();
-               }
-       }
+       return scheduler->select_next_thread();
 }
 
 /**
@@ -170,7 +169,7 @@ void ModelChecker::execute_sleep_set()
  * @param msg Descriptive message for the bug (do not include newline char)
  * @return True if bug is immediately-feasible
  */
-bool ModelChecker::assert_bug(const char *msg, ...)
+void ModelChecker::assert_bug(const char *msg, ...)
 {
        char str[800];
 
@@ -179,7 +178,7 @@ bool ModelChecker::assert_bug(const char *msg, ...)
        vsnprintf(str, sizeof(str), msg, ap);
        va_end(ap);
 
-       return execution->assert_bug(str);
+       execution->assert_bug(str);
 }
 
 /**
@@ -190,8 +189,8 @@ bool ModelChecker::assert_bug(const char *msg, ...)
 void ModelChecker::assert_user_bug(const char *msg)
 {
        /* If feasible bug, bail out now */
-       if (assert_bug(msg))
-               switch_to_master(NULL);
+       assert_bug(msg);
+       switch_to_master(NULL);
 }
 
 /** @brief Print bug report listing for this execution (if any bugs exist) */
@@ -200,10 +199,10 @@ void ModelChecker::print_bugs() const
        SnapVector<bug_message *> *bugs = execution->get_bugs();
 
        model_print("Bug report: %zu bug%s detected\n",
-                       bugs->size(),
-                       bugs->size() > 1 ? "s" : "");
-       for (unsigned int i = 0; i < bugs->size(); i++)
-               (*bugs)[i]->print();
+                                                       bugs->size(),
+                                                       bugs->size() > 1 ? "s" : "");
+       for (unsigned int i = 0;i < bugs->size();i++)
+               (*bugs)[i] -> print();
 }
 
 /**
@@ -214,16 +213,13 @@ void ModelChecker::print_bugs() const
  */
 void ModelChecker::record_stats()
 {
-       stats.num_total++;
-       if (!execution->isfeasibleprefix())
-               stats.num_infeasible++;
-       else if (execution->have_bug_reports())
-               stats.num_buggy_executions++;
+       stats.num_total ++;
+       if (execution->have_bug_reports())
+               stats.num_buggy_executions ++;
        else if (execution->is_complete_execution())
-               stats.num_complete++;
+               stats.num_complete ++;
        else {
-               stats.num_redundant++;
-
+               //All threads are sleeping
                /**
                 * @todo We can violate this ASSERT() when fairness/sleep sets
                 * conflict to cause an execution to terminate, e.g. with:
@@ -237,12 +233,8 @@ void ModelChecker::record_stats()
 void ModelChecker::print_stats() const
 {
        model_print("Number of complete, bug-free executions: %d\n", stats.num_complete);
-       model_print("Number of redundant executions: %d\n", stats.num_redundant);
        model_print("Number of buggy executions: %d\n", stats.num_buggy_executions);
-       model_print("Number of infeasible executions: %d\n", stats.num_infeasible);
        model_print("Total executions: %d\n", stats.num_total);
-       if (params.verbose)
-               model_print("Total nodes created: %d\n", node_stack->get_total_nodes());
 }
 
 /**
@@ -252,17 +244,10 @@ void ModelChecker::print_stats() const
 void ModelChecker::print_execution(bool printbugs) const
 {
        model_print("Program output from execution %d:\n",
-                       get_execution_number());
+                                                       get_execution_number());
        print_program_output();
 
-       if (params.verbose >= 2) {
-               model_print("\nEarliest divergence point since last feasible execution:\n");
-               if (earliest_diverge)
-                       earliest_diverge->print();
-               else
-                       model_print("(Not set)\n");
-
-               model_print("\n");
+       if (params.verbose >= 3) {
                print_stats();
        }
 
@@ -283,52 +268,39 @@ 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? */
-       bool complete = execution->isfeasibleprefix() &&
-               (execution->is_complete_execution() ||
-                execution->have_bug_reports());
+       bool complete = (execution->is_complete_execution() ||
+                                                                        execution->have_bug_reports());
 
        /* End-of-execution bug checks */
        if (complete) {
                if (execution->is_deadlocked())
                        assert_bug("Deadlock detected");
 
-               checkDataRaces();
                run_trace_analyses();
        }
 
        record_stats();
-
        /* Output */
-       if (params.verbose || (complete && execution->have_bug_reports()))
+       if ( (complete && params.verbose) || params.verbose>1 || (complete && execution->have_bug_reports()))
                print_execution(complete);
        else
                clear_program_output();
 
-       if (complete)
-               earliest_diverge = NULL;
-
-       if ((diverge = execution->get_next_backtrack()) == NULL)
-               return false;
-
-       if (DBG_ENABLED()) {
-               model_print("Next execution will diverge at:\n");
-               diverge->print();
-       }
-
-       execution_number++;
-
-       reset_to_initial_state();
-       return true;
+// test code
+       execution_number ++;
+       if (more_executions)
+               reset_to_initial_state();
+       history->set_new_exec_flag();
 }
 
 /** @brief Run trace analyses on complete trace */
 void ModelChecker::run_trace_analyses() {
-       for (unsigned int i = 0; i < trace_analyses.size(); i++)
-               trace_analyses[i]->analyze(execution->get_action_trace());
+       for (unsigned int i = 0;i < trace_analyses.size();i ++)
+               trace_analyses[i] -> analyze(execution->get_action_trace());
 }
 
 /**
@@ -377,10 +349,25 @@ void ModelChecker::switch_from_master(Thread *thread)
  */
 uint64_t ModelChecker::switch_to_master(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();
        scheduler->set_current_thread(NULL);
        ASSERT(!old->get_pending());
+
+       if (inspect_plugin != NULL) {
+               inspect_plugin->inspectModelAction(act);
+       }
+
        old->set_pending(act);
        if (Thread::swap(old, &system_context) < 0) {
                perror("swap threads");
@@ -389,43 +376,54 @@ uint64_t ModelChecker::switch_to_master(ModelAction *act)
        return old->get_return_value();
 }
 
-/** Wrapper to run the user's main function, with appropriate arguments */
-void user_main_wrapper(void *)
-{
-       user_main(model->params.argc, model->params.argv);
+static void runChecker() {
+       model->run();
+       delete model;
+}
+
+void ModelChecker::startChecker() {
+       startExecution(get_system_context(), runChecker);
+       snapshot = take_snapshot();
+       initMainThread();
 }
 
 bool ModelChecker::should_terminate_execution()
 {
-       /* Infeasible -> don't take any more steps */
-       if (execution->is_infeasible())
-               return true;
-       else if (execution->isfeasibleprefix() && execution->have_bug_reports()) {
+       if (execution->have_bug_reports()) {
                execution->set_assert();
                return true;
-       }
-
-       if (execution->too_many_steps())
+       } else if (execution->isFinished()) {
                return true;
+       }
        return false;
 }
 
 /** @brief Run ModelChecker for the user program */
 void ModelChecker::run()
 {
-       do {
-               thrd_t user_thread;
-               Thread *t = new Thread(execution->get_next_id(), &user_thread, &user_main_wrapper, NULL, NULL);
-               execution->add_thread(t);
+       //Need to initial random number generator state to avoid resets on rollback
+       char random_state[256];
+       initstate(423121, random_state, sizeof(random_state));
+       modelclock_t checkfree = params.checkthreshold;
+       for(int exec = 0;exec < params.maxexecutions;exec++) {
+               Thread * t = init_thread;
 
                do {
+                       /* Check whether we need to free model actions. */
+
+                       if (params.traceminsize != 0 &&
+                                       execution->get_curr_seq_num() > checkfree) {
+                               checkfree += params.checkthreshold;
+                               execution->collectActions();
+                       }
+
                        /*
                         * 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++) {
+                       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()) {
@@ -436,7 +434,7 @@ void ModelChecker::run()
                        }
 
                        /* Don't schedule threads which should be disabled */
-                       for (unsigned int i = 0; i < get_num_threads(); i++) {
+                       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)) {
@@ -444,30 +442,62 @@ void ModelChecker::run()
                                }
                        }
 
+                       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) */
+                       * 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());
-
-       } while (next_execution());
-
-       execution->fixup_release_sequences();
+               finish_execution((exec+1) < params.maxexecutions);
+               //restore random number generator state after rollback
+               setstate(random_state);
+       }
 
        model_print("******* Model-checking complete: *******\n");
        print_stats();
 
        /* Have the trace analyses dump their output. */
-       for (unsigned int i = 0; i < trace_analyses.size(); i++)
+       for (unsigned int i = 0;i < trace_analyses.size();i++)
                trace_analyses[i]->finish();
+
+       /* unlink tmp file created by last child process */
+       char filename[256];
+       snprintf_(filename, sizeof(filename), "C11FuzzerTmp%d", getpid());
+       unlink(filename);
 }