#include <stdio.h>
#include <algorithm>
#include <mutex>
+#include <new>
#include "model.h"
#include "action.h"
delete priv;
}
-static action_list_t * get_safe_ptr_action(HashTable<const void *, action_list_t *, uintptr_t, 4> * hash, void * ptr) {
- action_list_t * tmp=hash->get(ptr);
- if (tmp==NULL) {
- tmp=new action_list_t();
+static action_list_t * get_safe_ptr_action(HashTable<const void *, action_list_t *, uintptr_t, 4> * hash, void * ptr)
+{
+ action_list_t *tmp = hash->get(ptr);
+ if (tmp == NULL) {
+ tmp = new action_list_t();
hash->put(ptr, tmp);
}
return tmp;
}
-static std::vector<action_list_t> * get_safe_ptr_vect_action(HashTable<void *, std::vector<action_list_t> *, uintptr_t, 4> * hash, void * ptr) {
- std::vector<action_list_t> * tmp=hash->get(ptr);
- if (tmp==NULL) {
- tmp=new std::vector<action_list_t>();
+static std::vector<action_list_t> * get_safe_ptr_vect_action(HashTable<void *, std::vector<action_list_t> *, uintptr_t, 4> * hash, void * ptr)
+{
+ std::vector<action_list_t> *tmp = hash->get(ptr);
+ if (tmp == NULL) {
+ tmp = new std::vector<action_list_t>();
hash->put(ptr, tmp);
}
return tmp;
{
thread_id_t tid;
- if (curr!=NULL) {
+ if (curr != NULL) {
/* Do not split atomic actions. */
if (curr->is_rmwr())
return thread_current();
if (next == diverge) {
if (earliest_diverge == NULL || *diverge < *earliest_diverge)
- earliest_diverge=diverge;
+ earliest_diverge = diverge;
Node *nextnode = next->get_node();
Node *prevnode = nextnode->get_parent();
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();
+ if (diverge == earliest_diverge) {
+ earliest_diverge = prevnode->get_action();
}
}
/* The correct sleep set is in the parent node. */
* 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->get_enabled(thr) == THREAD_SLEEP_SET &&
- thr->get_pending() == NULL ) {
+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() == NULL) {
thr->set_state(THREAD_RUNNING);
scheduler->next_thread(thr);
Thread::swap(&system_context, thr);
priv->current_action = NULL;
}
-void ModelChecker::wake_up_sleeping_actions(ModelAction * curr) {
- 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->get_enabled(thr) == THREAD_SLEEP_SET ) {
- ModelAction *pending_act=thr->get_pending();
- if ((!curr->is_rmwr())&&pending_act->could_synchronize_with(curr)) {
+void ModelChecker::wake_up_sleeping_actions(ModelAction *curr)
+{
+ for (unsigned int i = 0; i < get_num_threads(); i++) {
+ Thread *thr = get_thread(int_to_id(i));
+ if (scheduler->is_sleep_set(thr)) {
+ ModelAction *pending_act = thr->get_pending();
+ if ((!curr->is_rmwr()) && pending_act->could_synchronize_with(curr))
//Remove this thread from sleep set
scheduler->remove_sleep(thr);
- }
}
}
}
void ModelChecker::set_backtracking(ModelAction *act)
{
Thread *t = get_thread(act);
- ModelAction * prev = get_last_conflict(act);
+ ModelAction *prev = get_last_conflict(act);
if (prev == NULL)
return;
- Node * node = prev->get_node()->get_parent();
+ Node *node = prev->get_node()->get_parent();
int low_tid, high_tid;
if (node->is_enabled(t)) {
low_tid = id_to_int(act->get_tid());
- high_tid = low_tid+1;
+ high_tid = low_tid + 1;
} else {
low_tid = 0;
high_tid = get_num_threads();
break;
/* Don't backtrack into a point where the thread is disabled or sleeping. */
- if (node->enabled_status(tid)!=THREAD_ENABLED)
+ if (node->enabled_status(tid) != THREAD_ENABLED)
continue;
/* Check if this has been explored already */
/* See if fairness allows */
if (model->params.fairwindow != 0 && !node->has_priority(tid)) {
- bool unfair=false;
- for(int t=0;t<node->get_num_threads();t++) {
- thread_id_t tother=int_to_id(t);
+ bool unfair = false;
+ for (int t = 0; t < node->get_num_threads(); t++) {
+ thread_id_t tother = int_to_id(t);
if (node->is_enabled(tother) && node->has_priority(tother)) {
- unfair=true;
+ unfair = true;
break;
}
}
/* Read from future value */
value = curr->get_node()->get_future_value();
modelclock_t expiration = curr->get_node()->get_future_value_expiration();
- read_from(curr, NULL);
+ curr->set_read_from(NULL);
Promise *valuepromise = new Promise(curr, value, expiration);
promises->push_back(valuepromise);
}
*
* @return True if synchronization was updated; false otherwise
*/
-bool ModelChecker::process_mutex(ModelAction *curr) {
- std::mutex *mutex=NULL;
- struct std::mutex_state *state=NULL;
+bool ModelChecker::process_mutex(ModelAction *curr)
+{
+ std::mutex *mutex = NULL;
+ struct std::mutex_state *state = NULL;
if (curr->is_trylock() || curr->is_lock() || curr->is_unlock()) {
mutex = (std::mutex *)curr->get_location();
}
waiters->clear();
//check whether we should go to sleep or not...simulate spurious failures
- if (curr->get_node()->get_misc()==0) {
+ if (curr->get_node()->get_misc() == 0) {
get_safe_ptr_action(condvar_waiters_map, curr->get_location())->push_back(curr);
//disable us
scheduler->sleep(get_current_thread());
}
case ATOMIC_NOTIFY_ONE: {
action_list_t *waiters = get_safe_ptr_action(condvar_waiters_map, curr->get_location());
- int wakeupthread=curr->get_node()->get_misc();
+ int wakeupthread = curr->get_node()->get_misc();
action_list_t::iterator it = waiters->begin();
advance(it, wakeupthread);
scheduler->wake(get_thread(*it));
return updated_mod_order || updated_promises;
}
+/**
+ * Process a fence ModelAction
+ * @param curr The ModelAction to process
+ * @return True if synchronization was updated
+ */
+bool ModelChecker::process_fence(ModelAction *curr)
+{
+ /*
+ * fence-relaxed: no-op
+ * fence-release: only log the occurence (not in this function), for
+ * use in later synchronization
+ * fence-acquire (this function): search for hypothetical release
+ * sequences
+ */
+ bool updated = false;
+ if (curr->is_acquire()) {
+ action_list_t *list = action_trace;
+ action_list_t::reverse_iterator rit;
+ /* Find X : is_read(X) && X --sb-> curr */
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *act = *rit;
+ if (act == curr)
+ continue;
+ if (act->get_tid() != curr->get_tid())
+ continue;
+ /* Stop at the beginning of the thread */
+ if (act->is_thread_start())
+ break;
+ /* Stop once we reach a prior fence-acquire */
+ if (act->is_fence() && act->is_acquire())
+ break;
+ if (!act->is_read())
+ continue;
+ /* read-acquire will find its own release sequences */
+ if (act->is_acquire())
+ continue;
+
+ /* Establish hypothetical release sequences */
+ rel_heads_list_t release_heads;
+ get_release_seq_heads(curr, act, &release_heads);
+ for (unsigned int i = 0; i < release_heads.size(); i++)
+ if (!curr->synchronize_with(release_heads[i]))
+ set_bad_synchronization();
+ if (release_heads.size() != 0)
+ updated = true;
+ }
+ }
+ return updated;
+}
+
/**
* @brief Process the current action for thread-related activity
*
*/
bool ModelChecker::check_action_enabled(ModelAction *curr) {
if (curr->is_lock()) {
- std::mutex * lock = (std::mutex *)curr->get_location();
- struct std::mutex_state * state = lock->get_state();
+ std::mutex *lock = (std::mutex *)curr->get_location();
+ struct std::mutex_state *state = lock->get_state();
if (state->islocked) {
//Stick the action in the appropriate waiting queue
get_safe_ptr_action(lock_waiters_map, curr->get_location())->push_back(curr);
if (act->is_write() && process_write(act))
update = true;
+ if (act->is_fence() && process_fence(act))
+ update_all = true;
+
if (act->is_mutex_op() && process_mutex(act))
update_all = true;
return get_next_thread(curr);
}
-void ModelChecker::check_curr_backtracking(ModelAction * curr) {
+void ModelChecker::check_curr_backtracking(ModelAction *curr)
+{
Node *currnode = curr->get_node();
Node *parnode = currnode->get_parent();
bool ModelChecker::promises_expired() const
{
- for (unsigned int promise_index = 0; promise_index < promises->size(); promise_index++) {
- Promise *promise = (*promises)[promise_index];
- if (promise->get_expiration()<priv->used_sequence_numbers) {
+ for (unsigned int i = 0; i < promises->size(); i++) {
+ Promise *promise = (*promises)[i];
+ if (promise->get_expiration() < priv->used_sequence_numbers)
return true;
- }
}
return false;
}
ModelAction * ModelChecker::process_rmw(ModelAction *act) {
ModelAction *lastread = get_last_action(act->get_tid());
lastread->process_rmw(act);
- if (act->is_rmw() && lastread->get_reads_from()!=NULL) {
+ if (act->is_rmw() && lastread->get_reads_from() != NULL) {
mo_graph->addRMWEdge(lastread->get_reads_from(), lastread);
mo_graph->commitChanges();
}
*
* If so, we decide that the execution is no longer feasible.
*/
-void ModelChecker::check_recency(ModelAction *curr, const ModelAction *rf) {
+void ModelChecker::check_recency(ModelAction *curr, const ModelAction *rf)
+{
if (params.maxreads != 0) {
-
if (curr->get_node()->get_read_from_size() <= 1)
return;
//Must make sure that execution is currently feasible... We could
//See if we have enough reads from the same value
int count = 0;
for (; count < params.maxreads; rit++,count++) {
- if (rit==list->rend())
+ if (rit == list->rend())
return;
ModelAction *act = *rit;
if (!act->is_read())
if (act->get_node()->get_read_from_size() <= 1)
return;
}
- for (int i = 0; i<curr->get_node()->get_read_from_size(); i++) {
- //Get write
- const ModelAction * write = curr->get_node()->get_read_from_at(i);
+ for (int i = 0; i < curr->get_node()->get_read_from_size(); i++) {
+ /* Get write */
+ const ModelAction *write = curr->get_node()->get_read_from_at(i);
- //Need a different write
- if (write==rf)
+ /* Need a different write */
+ if (write == rf)
continue;
/* Test to see whether this is a feasible write to read from*/
//new we need to see if this write works for everyone
for (int loop = count; loop>0; loop--,rit++) {
- ModelAction *act=*rit;
+ ModelAction *act = *rit;
bool foundvalue = false;
for (int j = 0; j<act->get_node()->get_read_from_size(); j++) {
- if (act->get_node()->get_read_from_at(j)==write) {
+ if (act->get_node()->get_read_from_at(j) == write) {
foundvalue = true;
break;
}
*act < *last_sc_fence_thread_local) {
mo_graph->addEdge(act, rf);
added = true;
+ break;
}
/* C++, Section 29.3 statement 4 */
else if (act->is_seqcst() && last_sc_fence_local &&
*act < *last_sc_fence_local) {
mo_graph->addEdge(act, rf);
added = true;
+ break;
}
/* C++, Section 29.3 statement 6 */
else if (last_sc_fence_thread_before &&
*act < *last_sc_fence_thread_before) {
mo_graph->addEdge(act, rf);
added = true;
+ break;
}
}
/* Include at most one act per-thread that "happens before" curr */
if (lastact != NULL) {
- if (lastact==curr) {
+ if (lastact== curr) {
//Case 1: The resolved read is a RMW, and we need to make sure
//that the write portion of the RMW mod order after rf
//is mod ordered after rf
const ModelAction *postreadfrom = lastact->get_reads_from();
- if (postreadfrom != NULL&&rf != postreadfrom)
+ if (postreadfrom != NULL && rf != postreadfrom)
mo_graph->addEdge(rf, postreadfrom);
} else {
//Case 3: The resolved read is a normal read and the next
//operation is a write, and we need to make sure that the
//write is mod ordered after rf
- if (lastact!=rf)
+ if (lastact != rf)
mo_graph->addEdge(rf, lastact);
}
break;
* continue processing list.
*/
if (curr->is_rmw()) {
- if (curr->get_reads_from()!=NULL)
+ if (curr->get_reads_from() != NULL)
break;
else
continue;
*act < *last_sc_fence_thread_before) {
mo_graph->addEdge(act, curr);
added = true;
+ break;
}
/*
/** Arbitrary reads from the future are not allowed. Section 29.3
* part 9 places some constraints. This method checks one result of constraint
* constraint. Others require compiler support. */
-bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, const ModelAction *reader) {
+bool ModelChecker::thin_air_constraint_may_allow(const ModelAction *writer, const ModelAction *reader)
+{
if (!writer->is_rmw())
return true;
}
}
- if (write_after_read && write_after_read!=writer && mo_graph->checkReachable(write_after_read, writer))
+ if (write_after_read && write_after_read != writer && mo_graph->checkReachable(write_after_read, writer))
return false;
}
return true;
void ModelChecker::add_action_to_lists(ModelAction *act)
{
int tid = id_to_int(act->get_tid());
- action_trace->push_back(act);
+ ModelAction *uninit = NULL;
+ int uninit_id = -1;
+ action_list_t *list = get_safe_ptr_action(obj_map, act->get_location());
+ if (list->empty() && act->is_atomic_var()) {
+ uninit = new_uninitialized_action(act->get_location());
+ uninit_id = id_to_int(uninit->get_tid());
+ list->push_back(uninit);
+ }
+ list->push_back(act);
- get_safe_ptr_action(obj_map, act->get_location())->push_back(act);
+ action_trace->push_back(act);
+ if (uninit)
+ action_trace->push_front(uninit);
std::vector<action_list_t> *vec = get_safe_ptr_vect_action(obj_thrd_map, act->get_location());
if (tid >= (int)vec->size())
vec->resize(priv->next_thread_id);
(*vec)[tid].push_back(act);
+ if (uninit)
+ (*vec)[uninit_id].push_front(uninit);
if ((int)thrd_last_action->size() <= tid)
thrd_last_action->resize(get_num_threads());
(*thrd_last_action)[tid] = act;
+ if (uninit)
+ (*thrd_last_action)[uninit_id] = uninit;
if (act->is_fence() && act->is_release()) {
if ((int)thrd_last_fence_release->size() <= tid)
}
if (act->is_wait()) {
- void *mutex_loc=(void *) act->get_value();
+ void *mutex_loc = (void *) act->get_value();
get_safe_ptr_action(obj_map, mutex_loc)->push_back(act);
std::vector<action_list_t> *vec = get_safe_ptr_vect_action(obj_thrd_map, mutex_loc);
//Check whether reading these writes has made threads unable to
//resolve promises
- for(unsigned int i=0;i<threads_to_check.size();i++)
+ for (unsigned int i = 0; i < threads_to_check.size(); i++)
mo_check_promises(threads_to_check[i], write);
return resolved;
* cannot perform a future write that will resolve the promise due to
* modificatin order constraints.
*
- * @parem tid The thread that either read from the model action
+ * @param tid The thread that either read from the model action
* write, or actually did the model action write.
*
- * @parem write The ModelAction representing the relevant write.
+ * @param write The ModelAction representing the relevant write.
*/
-
-void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write) {
- void * location = write->get_location();
+void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write)
+{
+ void *location = write->get_location();
for (unsigned int i = 0; i < promises->size(); i++) {
Promise *promise = (*promises)[i];
const ModelAction *act = promise->get_action();
continue;
//same thread as the promise
- if ( act->get_tid()==tid ) {
+ if ( act->get_tid() == tid ) {
//do we have a pwrite for the promise, if not, set it
if (promise->get_write() == NULL ) {
ModelAction *last_sc_write = NULL;
- /* Track whether this object has been initialized */
- bool initialized = false;
-
- if (curr->is_seqcst()) {
+ if (curr->is_seqcst())
last_sc_write = get_last_seq_cst_write(curr);
- /* We have to at least see the last sequentially consistent write,
- so we are initialized. */
- if (last_sc_write != NULL)
- initialized = true;
- }
/* Iterate over all threads */
for (i = 0; i < thrd_lists->size(); i++) {
}
/* Include at most one act per-thread that "happens before" curr */
- if (act->happens_before(curr)) {
- initialized = true;
+ if (act->happens_before(curr))
break;
- }
}
}
- if (!initialized)
- assert_bug("May read from uninitialized atomic");
-
- if (DBG_ENABLED() || !initialized) {
+ if (DBG_ENABLED()) {
model_print("Reached read action:\n");
curr->print();
model_print("Printing may_read_from\n");
}
}
-bool ModelChecker::sleep_can_read_from(ModelAction * curr, const ModelAction *write) {
- while(true) {
- Node *prevnode=write->get_node()->get_parent();
+bool ModelChecker::sleep_can_read_from(ModelAction *curr, const ModelAction *write)
+{
+ while (true) {
+ /* UNINIT actions don't have a Node, and they never sleep */
+ if (write->is_uninitialized())
+ return true;
+ Node *prevnode = write->get_node()->get_parent();
- bool thread_sleep=prevnode->enabled_status(curr->get_tid())==THREAD_SLEEP_SET;
- if (write->is_release()&&thread_sleep)
+ bool thread_sleep = prevnode->enabled_status(curr->get_tid()) == THREAD_SLEEP_SET;
+ if (write->is_release() && thread_sleep)
return true;
if (!write->is_rmw()) {
return false;
}
- if (write->get_reads_from()==NULL)
+ if (write->get_reads_from() == NULL)
return true;
- write=write->get_reads_from();
+ write = write->get_reads_from();
}
}
+/**
+ * @brief Create a new action representing an uninitialized atomic
+ * @param location The memory location of the atomic object
+ * @return A pointer to a new ModelAction
+ */
+ModelAction * ModelChecker::new_uninitialized_action(void *location) const
+{
+ ModelAction *act = (ModelAction *)snapshot_malloc(sizeof(class ModelAction));
+ act = new (act) ModelAction(ATOMIC_UNINIT, std::memory_order_relaxed, location, 0, model_thread);
+ act->create_cv(NULL);
+ return act;
+}
+
static void print_list(action_list_t *list, int exec_num = -1)
{
action_list_t::iterator it;
if (exec_num >= 0)
model_print("Execution %d:\n", exec_num);
- unsigned int hash=0;
+ unsigned int hash = 0;
for (it = list->begin(); it != list->end(); it++) {
(*it)->print();
- hash=hash^(hash<<3)^((*it)->hash());
+ hash = hash^(hash<<3)^((*it)->hash());
}
model_print("HASH %u\n", hash);
model_print("---------------------------------------------------------------------\n");
void ModelChecker::dumpGraph(char *filename) {
char buffer[200];
sprintf(buffer, "%s.dot",filename);
- FILE *file=fopen(buffer, "w");
+ FILE *file = fopen(buffer, "w");
fprintf(file, "digraph %s {\n",filename);
mo_graph->dumpNodes(file);
- ModelAction ** thread_array=(ModelAction **)model_calloc(1, sizeof(ModelAction *)*get_num_threads());
+ ModelAction **thread_array = (ModelAction **)model_calloc(1, sizeof(ModelAction *)*get_num_threads());
for (action_list_t::iterator it = action_trace->begin(); it != action_trace->end(); it++) {
- ModelAction *action=*it;
+ ModelAction *action = *it;
if (action->is_read()) {
fprintf(file, "N%u [label=\"%u, T%u\"];\n", action->get_seq_number(),action->get_seq_number(), action->get_tid());
- if (action->get_reads_from()!=NULL)
+ if (action->get_reads_from() != NULL)
fprintf(file, "N%u -> N%u[label=\"rf\", color=red];\n", action->get_seq_number(), action->get_reads_from()->get_seq_number());
}
if (thread_array[action->get_tid()] != NULL) {
fprintf(file, "N%u -> N%u[label=\"sb\", color=blue];\n", thread_array[action->get_tid()]->get_seq_number(), action->get_seq_number());
}
- thread_array[action->get_tid()]=action;
+ thread_array[action->get_tid()] = action;
}
fprintf(file,"}\n");
model_free(thread_array);
* @param act The current action that will be explored. May be NULL only if
* trace is exiting via an assertion (see ModelChecker::set_assert and
* ModelChecker::has_asserted).
- * @return Return status from the 'swap' call (i.e., success/fail, 0/-1)
+ * @return Return the value returned by the current action
*/
-int ModelChecker::switch_to_master(ModelAction *act)
+uint64_t ModelChecker::switch_to_master(ModelAction *act)
{
DBG();
Thread *old = thread_current();
set_current_action(act);
old->set_state(THREAD_READY);
- return Thread::swap(old, &system_context);
+ if (Thread::swap(old, &system_context) < 0) {
+ perror("swap threads");
+ exit(EXIT_FAILURE);
+ }
+ return old->get_return_value();
}
/**
projects / model-checker.git / blobdiff