10 #include "nodestack.h"
12 #include "snapshot-interface.h"
15 #include "threads-model.h"
17 #include "traceanalysis.h"
18 #include "execution.h"
19 #include "bugmessage.h"
23 /** @brief Constructor */
24 ModelChecker::ModelChecker() :
25 /* Initialize default scheduler */
28 scheduler(new Scheduler()),
29 node_stack(new NodeStack()),
30 execution(new ModelExecution(this, scheduler, node_stack)),
35 memset(&stats,0,sizeof(struct execution_stats));
38 /** @brief Destructor */
39 ModelChecker::~ModelChecker()
45 /** Method to set parameters */
46 void ModelChecker::setParams(struct model_params params) {
47 this->params = params;
48 execution->setParams(¶ms);
52 * Restores user program to initial state and resets all model-checker data
55 void ModelChecker::reset_to_initial_state()
57 DEBUG("+++ Resetting to initial state +++\n");
58 node_stack->reset_execution();
61 * FIXME: if we utilize partial rollback, we will need to free only
62 * those pending actions which were NOT pending before the rollback
65 for (unsigned int i = 0;i < get_num_threads();i++)
66 delete get_thread(int_to_id(i))->get_pending();
68 snapshot_backtrack_before(0);
71 /** @return the number of user threads created during this execution */
72 unsigned int ModelChecker::get_num_threads() const
74 return execution->get_num_threads();
78 * Must be called from user-thread context (e.g., through the global
79 * thread_current() interface)
81 * @return The currently executing Thread.
83 Thread * ModelChecker::get_current_thread() const
85 return scheduler->get_current_thread();
89 * @brief Choose the next thread to execute.
91 * This function chooses the next thread that should execute. It can enforce
92 * execution replay/backtracking or, if the model-checker has no preference
93 * regarding the next thread (i.e., when exploring a new execution ordering),
94 * we defer to the scheduler.
96 * @return The next chosen thread to run, if any exist. Or else if the current
97 * execution should terminate, return NULL.
99 Thread * ModelChecker::get_next_thread()
103 * Have we completed exploring the preselected path? Then let the
106 return scheduler->select_next_thread(node_stack->get_head());
110 * @brief Assert a bug in the executing program.
112 * Use this function to assert any sort of bug in the user program. If the
113 * current trace is feasible (actually, a prefix of some feasible execution),
114 * then this execution will be aborted, printing the appropriate message. If
115 * the current trace is not yet feasible, the error message will be stashed and
116 * printed if the execution ever becomes feasible.
118 * @param msg Descriptive message for the bug (do not include newline char)
119 * @return True if bug is immediately-feasible
121 bool ModelChecker::assert_bug(const char *msg, ...)
127 vsnprintf(str, sizeof(str), msg, ap);
130 return execution->assert_bug(str);
134 * @brief Assert a bug in the executing program, asserted by a user thread
135 * @see ModelChecker::assert_bug
136 * @param msg Descriptive message for the bug (do not include newline char)
138 void ModelChecker::assert_user_bug(const char *msg)
140 /* If feasible bug, bail out now */
142 switch_to_master(NULL);
145 /** @brief Print bug report listing for this execution (if any bugs exist) */
146 void ModelChecker::print_bugs() const
148 SnapVector<bug_message *> *bugs = execution->get_bugs();
150 model_print("Bug report: %zu bug%s detected\n",
152 bugs->size() > 1 ? "s" : "");
153 for (unsigned int i = 0;i < bugs->size();i++)
154 (*bugs)[i] -> print();
158 * @brief Record end-of-execution stats
160 * Must be run when exiting an execution. Records various stats.
161 * @see struct execution_stats
163 void ModelChecker::record_stats()
166 if (!execution->isfeasibleprefix())
167 stats.num_infeasible ++;
168 else if (execution->have_bug_reports())
169 stats.num_buggy_executions ++;
170 else if (execution->is_complete_execution())
171 stats.num_complete ++;
173 stats.num_redundant ++;
176 * @todo We can violate this ASSERT() when fairness/sleep sets
177 * conflict to cause an execution to terminate, e.g. with:
178 * Scheduler: [0: disabled][1: disabled][2: sleep][3: current, enabled]
180 //ASSERT(scheduler->all_threads_sleeping());
184 /** @brief Print execution stats */
185 void ModelChecker::print_stats() const
187 model_print("Number of complete, bug-free executions: %d\n", stats.num_complete);
188 model_print("Number of redundant executions: %d\n", stats.num_redundant);
189 model_print("Number of buggy executions: %d\n", stats.num_buggy_executions);
190 model_print("Number of infeasible executions: %d\n", stats.num_infeasible);
191 model_print("Total executions: %d\n", stats.num_total);
195 * @brief End-of-exeuction print
196 * @param printbugs Should any existing bugs be printed?
198 void ModelChecker::print_execution(bool printbugs) const
200 model_print("Program output from execution %d:\n",
201 get_execution_number());
202 print_program_output();
204 if (params.verbose >= 3) {
208 /* Don't print invalid bugs */
209 if (printbugs && execution->have_bug_reports()) {
215 execution->print_summary();
219 * Queries the model-checker for more executions to explore and, if one
220 * exists, resets the model-checker state to execute a new execution.
222 * @return If there are more executions to explore, return true. Otherwise,
225 bool ModelChecker::next_execution()
228 /* Is this execution a feasible execution that's worth bug-checking? */
229 bool complete = execution->isfeasibleprefix() &&
230 (execution->is_complete_execution() ||
231 execution->have_bug_reports());
233 /* End-of-execution bug checks */
235 if (execution->is_deadlocked())
236 assert_bug("Deadlock detected");
239 run_trace_analyses();
244 if ( (complete && params.verbose) || params.verbose>1 || (complete && execution->have_bug_reports()))
245 print_execution(complete);
247 clear_program_output();
255 reset_to_initial_state();
256 node_stack->full_reset();
260 /** @brief Run trace analyses on complete trace */
261 void ModelChecker::run_trace_analyses() {
262 for (unsigned int i = 0;i < trace_analyses.size();i ++)
263 trace_analyses[i] -> analyze(execution->get_action_trace());
267 * @brief Get a Thread reference by its ID
268 * @param tid The Thread's ID
269 * @return A Thread reference
271 Thread * ModelChecker::get_thread(thread_id_t tid) const
273 return execution->get_thread(tid);
277 * @brief Get a reference to the Thread in which a ModelAction was executed
278 * @param act The ModelAction
279 * @return A Thread reference
281 Thread * ModelChecker::get_thread(const ModelAction *act) const
283 return execution->get_thread(act);
287 * Switch from a model-checker context to a user-thread context. This is the
288 * complement of ModelChecker::switch_to_master and must be called from the
289 * model-checker context
291 * @param thread The user-thread to switch to
293 void ModelChecker::switch_from_master(Thread *thread)
295 scheduler->set_current_thread(thread);
296 Thread::swap(&system_context, thread);
300 * Switch from a user-context to the "master thread" context (a.k.a. system
301 * context). This switch is made with the intention of exploring a particular
302 * model-checking action (described by a ModelAction object). Must be called
303 * from a user-thread context.
305 * @param act The current action that will be explored. May be NULL only if
306 * trace is exiting via an assertion (see ModelExecution::set_assert and
307 * ModelExecution::has_asserted).
308 * @return Return the value returned by the current action
310 uint64_t ModelChecker::switch_to_master(ModelAction *act)
313 Thread *old = thread_current();
314 scheduler->set_current_thread(NULL);
315 ASSERT(!old->get_pending());
317 if (inspect_plugin != NULL) {
318 inspect_plugin->inspectModelAction(act);
320 old->set_pending(act);
321 if (Thread::swap(old, &system_context) < 0) {
322 perror("swap threads");
325 return old->get_return_value();
328 /** Wrapper to run the user's main function, with appropriate arguments */
329 void user_main_wrapper(void *)
331 user_main(model->params.argc, model->params.argv);
334 bool ModelChecker::should_terminate_execution()
336 /* Infeasible -> don't take any more steps */
337 if (execution->is_infeasible())
339 else if (execution->isfeasibleprefix() && execution->have_bug_reports()) {
340 execution->set_assert();
346 /** @brief Restart ModelChecker upon returning to the run loop of the
348 void ModelChecker::restart()
353 void ModelChecker::do_restart()
355 restart_flag = false;
356 reset_to_initial_state();
357 node_stack->full_reset();
358 memset(&stats,0,sizeof(struct execution_stats));
359 execution_number = 1;
362 /** @brief Run ModelChecker for the user program */
363 void ModelChecker::run()
365 //Need to initial random number generator state to avoid resets on rollback
366 char random_state[256];
367 initstate(423121, random_state, sizeof(random_state));
369 for(int exec = 0;exec < params.maxexecutions;exec ++) {
371 Thread *t = new Thread(execution->get_next_id(), &user_thread, &user_main_wrapper, NULL, NULL); // L: user_main_wrapper passes the user program
372 execution->add_thread(t);
373 //Need to seed random number generator, otherwise its state gets reset
376 * Stash next pending action(s) for thread(s). There
377 * should only need to stash one thread's action--the
378 * thread which just took a step--plus the first step
379 * for any newly-created thread
382 for (unsigned int i = 0;i < get_num_threads();i++) {
383 thread_id_t tid = int_to_id(i);
384 Thread *thr = get_thread(tid);
385 if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) {
386 switch_from_master(thr); // L: context swapped, and action type of thr changed.
387 if (thr->is_waiting_on(thr))
388 assert_bug("Deadlock detected (thread %u)", i);
392 /* Don't schedule threads which should be disabled */
393 for (unsigned int i = 0;i < get_num_threads();i++) {
394 Thread *th = get_thread(int_to_id(i));
395 ModelAction *act = th->get_pending();
396 if (act && execution->is_enabled(th) && !execution->check_action_enabled(act)) {
397 scheduler->sleep(th);
401 for (unsigned int i = 1;i < get_num_threads();i++) {
402 Thread *th = get_thread(int_to_id(i));
403 ModelAction *act = th->get_pending();
404 if (act && execution->is_enabled(th) && (th->get_state() != THREAD_BLOCKED) ) {
405 if (act->is_write()) {
406 std::memory_order order = act->get_mo();
407 if (order == std::memory_order_relaxed || \
408 order == std::memory_order_release) {
412 } else if (act->get_type() == THREAD_CREATE || \
413 act->get_type() == PTHREAD_CREATE || \
414 act->get_type() == THREAD_START || \
415 act->get_type() == THREAD_FINISH) {
422 /* Catch assertions from prior take_step or from
423 * between-ModelAction bugs (e.g., data races) */
425 if (execution->has_asserted())
428 t = get_next_thread();
429 if (!t || t->is_model_thread())
432 /* Consume the next action for a Thread */
433 ModelAction *curr = t->get_pending();
434 t->set_pending(NULL);
435 t = execution->take_step(curr);
436 } while (!should_terminate_execution());
438 //restore random number generator state after rollback
439 setstate(random_state);
442 model_print("******* Model-checking complete: *******\n");
445 /* Have the trace analyses dump their output. */
446 for (unsigned int i = 0;i < trace_analyses.size();i++)
447 trace_analyses[i]->finish();