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
*
act->set_read_from(rf);
if (rf != NULL && act->is_acquire()) {
rel_heads_list_t release_heads;
- get_release_seq_heads(act, &release_heads);
+ get_release_seq_heads(act, act, &release_heads);
int num_heads = release_heads.size();
for (unsigned int i = 0; i < release_heads.size(); i++)
if (!act->synchronize_with(release_heads[i])) {
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;
if (rf->is_release())
release_heads->push_back(rf);
+ else if (rf->get_last_fence_release())
+ release_heads->push_back(rf->get_last_fence_release());
if (!rf->is_rmw())
break; /* End of RMW chain */
if (rf->is_release())
return true; /* complete */
- /* else relaxed write; check modification order for contiguous subsequence
- * -> rf must be same thread as release */
+ /* else relaxed write
+ * - check for fence-release in the same thread (29.8, stmt. 3)
+ * - check modification order for contiguous subsequence
+ * -> rf must be same thread as release */
+
+ const ModelAction *fence_release = rf->get_last_fence_release();
+ /* Synchronize with a fence-release unconditionally; we don't need to
+ * find any more "contiguous subsequence..." for it */
+ if (fence_release)
+ release_heads->push_back(fence_release);
+
int tid = id_to_int(rf->get_tid());
std::vector<action_list_t> *thrd_lists = get_safe_ptr_vect_action(obj_thrd_map, rf->get_location());
action_list_t *list = &(*thrd_lists)[tid];
rit = std::find(list->rbegin(), list->rend(), rf);
ASSERT(rit != list->rend());
- /* Find the last write/release */
- for (; rit != list->rend(); rit++)
+ /* Find the last {write,fence}-release */
+ for (; rit != list->rend(); rit++) {
+ if (fence_release && *(*rit) < *fence_release)
+ break;
if ((*rit)->is_release())
break;
+ }
if (rit == list->rend()) {
/* No write-release in this thread */
return true; /* complete */
- }
+ } else if (fence_release && *(*rit) < *fence_release) {
+ /* The fence-release is more recent (and so, "stronger") than
+ * the most recent write-release */
+ return true; /* complete */
+ } /* else, need to establish contiguous release sequence */
ModelAction *release = *rit;
ASSERT(rf->same_thread(release));
* given ModelAction must synchronize. This function only returns a non-empty
* result when it can locate a release sequence head with certainty. Otherwise,
* it may mark the internal state of the ModelChecker so that it will handle
- * the release sequence at a later time, causing @a act to update its
+ * the release sequence at a later time, causing @a acquire to update its
* synchronization at some later point in execution.
- * @param act The 'acquire' action that may read from a release sequence
+ *
+ * @param acquire The 'acquire' action that may synchronize with a release
+ * sequence
+ * @param read The read action that may read from a release sequence; this may
+ * be the same as acquire, or else an earlier action in the same thread (i.e.,
+ * when 'acquire' is a fence-acquire)
* @param release_heads A pass-by-reference return parameter. Will be filled
* with the head(s) of the release sequence(s), if they exists with certainty.
* @see ModelChecker::release_seq_heads
*/
-void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *release_heads)
+void ModelChecker::get_release_seq_heads(ModelAction *acquire,
+ ModelAction *read, rel_heads_list_t *release_heads)
{
- const ModelAction *rf = act->get_reads_from();
+ const ModelAction *rf = read->get_reads_from();
struct release_seq *sequence = (struct release_seq *)snapshot_calloc(1, sizeof(struct release_seq));
- sequence->acquire = act;
+ sequence->acquire = acquire;
+ sequence->read = read;
if (!release_seq_heads(rf, release_heads, sequence)) {
/* add act to 'lazy checking' list */
std::vector< struct release_seq *, SnapshotAlloc<struct release_seq *> >::iterator it = pending_rel_seqs->begin();
while (it != pending_rel_seqs->end()) {
struct release_seq *pending = *it;
- ModelAction *act = pending->acquire;
+ ModelAction *acquire = pending->acquire;
+ const ModelAction *read = pending->read;
/* Only resolve sequences on the given location, if provided */
- if (location && act->get_location() != location) {
+ if (location && read->get_location() != location) {
it++;
continue;
}
- const ModelAction *rf = act->get_reads_from();
+ const ModelAction *rf = read->get_reads_from();
rel_heads_list_t release_heads;
bool complete;
complete = release_seq_heads(rf, &release_heads, pending);
for (unsigned int i = 0; i < release_heads.size(); i++) {
- if (!act->has_synchronized_with(release_heads[i])) {
- if (act->synchronize_with(release_heads[i]))
+ if (!acquire->has_synchronized_with(release_heads[i])) {
+ if (acquire->synchronize_with(release_heads[i]))
updated = true;
else
set_bad_synchronization();
if (updated) {
/* Re-check all pending release sequences */
work_queue->push_back(CheckRelSeqWorkEntry(NULL));
- /* Re-check act for mo_graph edges */
- work_queue->push_back(MOEdgeWorkEntry(act));
+ /* Re-check read-acquire for mo_graph edges */
+ if (acquire->is_read())
+ work_queue->push_back(MOEdgeWorkEntry(acquire));
/* propagate synchronization to later actions */
action_list_t::reverse_iterator rit = action_trace->rbegin();
- for (; (*rit) != act; rit++) {
+ for (; (*rit) != acquire; rit++) {
ModelAction *propagate = *rit;
- if (act->happens_before(propagate)) {
- propagate->synchronize_with(act);
+ if (acquire->happens_before(propagate)) {
+ propagate->synchronize_with(acquire);
/* Re-check 'propagate' for mo_graph edges */
work_queue->push_back(MOEdgeWorkEntry(propagate));
}
projects / c11tester.git / blobdiff