Add some debug support code

[c11tester.git] / model.cc

diff --git a/model.cc b/model.cc
index 52dd16f75cb7baf07fca1f0c31c66815d629a665..5b5ccf701c1798f9627c352f6ae50be4159fc929 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -26,11 +26,41 @@ 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() :
        /* Initialize default scheduler */
        params(),
-       restart_flag(false),
        scheduler(new Scheduler()),
        history(new ModelHistory()),
        execution(new ModelExecution(this, scheduler)),
@@ -39,9 +69,9 @@ ModelChecker::ModelChecker() :
        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");
+                                                       "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
@@ -57,6 +87,7 @@ ModelChecker::ModelChecker() :
        /* Configure output redirection for the model-checker */
        redirect_output();
        install_trace_analyses(get_execution());
+       install_handler();
 }
 
 /** @brief Destructor */
@@ -85,7 +116,7 @@ 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 */
@@ -237,7 +268,7 @@ 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? */
@@ -259,15 +290,11 @@ 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 */
@@ -356,8 +383,8 @@ 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()
@@ -371,38 +398,25 @@ 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));
-
+       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
@@ -470,7 +484,7 @@ void ModelChecker::run()
                        t->set_pending(NULL);
                        t = execution->take_step(curr);
                } while (!should_terminate_execution());
-               next_execution();
+               finish_execution((exec+1) < params.maxexecutions);
                //restore random number generator state after rollback
                setstate(random_state);
        }