#include "threads-model.h"
#include "bugmessage.h"
+#include <pthread.h>
+
#define INITIAL_THREAD_ID 0
/**
next_backtrack(NULL),
bugs(),
failed_promise(false),
+ hard_failed_promise(false),
too_many_reads(false),
no_valid_reads(false),
bad_synchronization(false),
+ bad_sc_read(false),
asserted(false)
{ }
ModelAction *next_backtrack;
SnapVector<bug_message *> bugs;
bool failed_promise;
+ bool hard_failed_promise;
bool too_many_reads;
bool no_valid_reads;
/** @brief Incorrectly-ordered synchronization was made */
bool bad_synchronization;
+ bool bad_sc_read;
bool asserted;
SNAPSHOTALLOC
mo_graph(new CycleGraph())
{
/* Initialize a model-checker thread, for special ModelActions */
- model_thread = new Thread(get_next_id());
- add_thread(model_thread);
+ model_thread = new Thread(get_next_id()); // L: Create model thread
+ add_thread(model_thread); // L: Add model thread to scheduler
scheduler->register_engine(this);
node_stack->register_engine(this);
}
priv->bad_synchronization = true;
}
+/** @brief Alert the model-checker that an incorrectly-ordered
+ * synchronization was made */
+void ModelExecution::set_bad_sc_read()
+{
+ priv->bad_sc_read = true;
+}
+
bool ModelExecution::assert_bug(const char *msg)
{
priv->bugs.push_back(new bug_message(msg));
/**
* @brief Check if the current pending promises allow a future value to be sent
*
- * If one of the following is true:
- * (a) there are no pending promises
- * (b) the reader and writer do not cross any promises
- * Then, it is safe to pass a future value back now.
+ * It is unsafe to pass a future value back if there exists a pending promise Pr
+ * such that:
+ *
+ * reader --exec-> Pr --exec-> writer
*
- * Otherwise, we must save the pending future value until (a) or (b) is true
+ * If such Pr exists, we must save the pending future value until Pr is
+ * resolved.
*
* @param writer The operation which sends the future value. Must be a write.
* @param reader The operation which will observe the value. Must be a read.
bool ModelExecution::promises_may_allow(const ModelAction *writer,
const ModelAction *reader) const
{
- if (promises.empty())
- return true;
for (int i = promises.size() - 1; i >= 0; i--) {
ModelAction *pr = promises[i]->get_reader(0);
//reader is after promise...doesn't cross any promise
/**
* Process a write ModelAction
* @param curr The ModelAction to process
+ * @param work The work queue, for adding fixup work
* @return True if the mo_graph was updated or promises were resolved
*/
-bool ModelExecution::process_write(ModelAction *curr)
+bool ModelExecution::process_write(ModelAction *curr, work_queue_t *work)
{
/* Readers to which we may send our future value */
ModelVector<ModelAction *> send_fv;
if (promise) {
earliest_promise_reader = promise->get_reader(0);
- updated_promises = resolve_promise(curr, promise);
+ updated_promises = resolve_promise(curr, promise, work);
} else
earliest_promise_reader = NULL;
thrd_t *thrd = (thrd_t *)curr->get_location();
struct thread_params *params = (struct thread_params *)curr->get_value();
Thread *th = new Thread(get_next_id(), thrd, params->func, params->arg, get_thread(curr));
+ curr->set_thread_operand(th);
+ add_thread(th);
+ th->set_creation(curr);
+ /* Promises can be satisfied by children */
+ for (unsigned int i = 0; i < promises.size(); i++) {
+ Promise *promise = promises[i];
+ if (promise->thread_is_available(curr->get_tid()))
+ promise->add_thread(th->get_id());
+ }
+ break;
+ }
+ case PTHREAD_CREATE: {
+ thrd_t *thrd = (thrd_t *)curr->get_location();
+ struct pthread_params *params = (struct pthread_params *)curr->get_value();
+ Thread *th = new Thread(get_next_id(), thrd, params->func, params->arg, get_thread(curr));
+ curr->set_thread_operand(th);
add_thread(th);
th->set_creation(curr);
/* Promises can be satisfied by children */
updated = true; /* trigger rel-seq checks */
break;
}
+ case PTHREAD_JOIN: {
+ Thread *blocking = curr->get_thread_operand();
+ ModelAction *act = get_last_action(blocking->get_id());
+ synchronize(act, curr);
+ updated = true; /* trigger rel-seq checks */
+ break; // WL: to be add (modified)
+ }
+
case THREAD_FINISH: {
Thread *th = get_thread(curr);
/* Wake up any joining threads */
/* Must synchronize */
if (!synchronize(release, acquire))
return;
- /* Re-check all pending release sequences */
- work_queue->push_back(CheckRelSeqWorkEntry(NULL));
- /* Re-check act for mo_graph edges */
- work_queue->push_back(MOEdgeWorkEntry(acquire));
-
- /* propagate synchronization to later actions */
- action_list_t::reverse_iterator rit = action_trace.rbegin();
- for (; (*rit) != acquire; rit++) {
- ModelAction *propagate = *rit;
- if (acquire->happens_before(propagate)) {
- synchronize(acquire, propagate);
- /* Re-check 'propagate' for mo_graph edges */
- work_queue->push_back(MOEdgeWorkEntry(propagate));
- }
- }
+
+ /* Propagate the changed clock vector */
+ propagate_clockvector(acquire, work_queue);
} else {
/* Break release sequence with new edges:
* release --mo--> write --mo--> rf */
*
* @return True if this read established synchronization
*/
+
bool ModelExecution::read_from(ModelAction *act, const ModelAction *rf)
{
ASSERT(rf);
if (act->is_read() && !second_part_of_rmw && process_read(act))
update = true;
- if (act->is_write() && process_write(act))
+ if (act->is_write() && process_write(act, &work_queue))
update = true;
if (act->is_fence() && process_fence(act))
if (rf) {
if (r_modification_order(act, rf))
updated = true;
+ if (act->is_seqcst()) {
+ ModelAction *last_sc_write = get_last_seq_cst_write(act);
+ if (last_sc_write != NULL && rf->happens_before(last_sc_write)) {
+ set_bad_sc_read();
+ }
+ }
} else if (promise) {
if (r_modification_order(act, promise))
updated = true;
char *ptr = buf;
if (mo_graph->checkForCycles())
ptr += sprintf(ptr, "[mo cycle]");
- if (priv->failed_promise)
+ if (priv->failed_promise || priv->hard_failed_promise)
ptr += sprintf(ptr, "[failed promise]");
if (priv->too_many_reads)
ptr += sprintf(ptr, "[too many reads]");
ptr += sprintf(ptr, "[no valid reads-from]");
if (priv->bad_synchronization)
ptr += sprintf(ptr, "[bad sw ordering]");
+ if (priv->bad_sc_read)
+ ptr += sprintf(ptr, "[bad sc read]");
if (promises_expired())
ptr += sprintf(ptr, "[promise expired]");
if (promises.size() != 0)
ptr += sprintf(ptr, "[unresolved promise]");
if (ptr != buf)
- model_print("%s: %s\n", prefix ? prefix : "Infeasible", buf);
+ model_print("%s: %s", prefix ? prefix : "Infeasible", buf);
}
/**
*/
bool ModelExecution::is_feasible_prefix_ignore_relseq() const
{
- return !is_infeasible() && promises.size() == 0;
+ return !is_infeasible() && promises.size() == 0 && ! priv->failed_promise;
+
}
/**
{
return mo_graph->checkForCycles() ||
priv->no_valid_reads ||
- priv->failed_promise ||
priv->too_many_reads ||
priv->bad_synchronization ||
+ priv->bad_sc_read ||
+ priv->hard_failed_promise ||
promises_expired();
}
}
}
- /* C++, Section 29.3 statement 3 (second subpoint) */
- if (curr->is_seqcst() && last_sc_write && act == last_sc_write) {
- added = mo_graph->addEdge(act, rf) || added;
- break;
- }
-
/*
* Include at most one act per-thread that "happens
* before" curr
added = mo_graph->addEdge(act, curr) || added;
else if (act->is_read()) {
//if previous read accessed a null, just keep going
- if (act->get_reads_from() == NULL)
- continue;
- added = mo_graph->addEdge(act->get_reads_from(), curr) || added;
+ if (act->get_reads_from() == NULL) {
+ added = mo_graph->addEdge(act->get_reads_from_promise(), curr) || added;
+ } else
+ added = mo_graph->addEdge(act->get_reads_from(), curr) || added;
}
break;
} else if (act->is_read() && !act->could_synchronize_with(curr) &&
pendingfuturevalue.
*/
- if (send_fv && thin_air_constraint_may_allow(curr, act)) {
+
+ if (send_fv && thin_air_constraint_may_allow(curr, act) && check_coherence_promise(curr, act)) {
if (!is_infeasible())
send_fv->push_back(act);
else if (curr->is_rmw() && act->is_rmw() && curr->get_reads_from() && curr->get_reads_from() == act->get_reads_from())
return added;
}
+//This procedure uses cohere to prune future values that are
+//guaranteed to generate a coherence violation.
+//
+//need to see if there is (1) a promise for thread write, (2)
+//the promise is sb before write, (3) the promise can only be
+//resolved by the thread read, and (4) the promise has same
+//location as read/write
+
+bool ModelExecution::check_coherence_promise(const ModelAction * write, const ModelAction *read) {
+ thread_id_t write_tid=write->get_tid();
+ for(unsigned int i = promises.size(); i>0; i--) {
+ Promise *pr=promises[i-1];
+ if (!pr->same_location(write))
+ continue;
+ //the reading thread is the only thread that can resolve the promise
+ if (pr->get_num_was_available_threads()==1 && pr->thread_was_available(read->get_tid())) {
+ for(unsigned int j=0;j<pr->get_num_readers();j++) {
+ ModelAction *prreader=pr->get_reader(j);
+ //the writing thread reads from the promise before the write
+ if (prreader->get_tid()==write_tid &&
+ (*prreader)<(*write)) {
+ if ((*read)>(*prreader)) {
+ //check that we don't have a read between the read and promise
+ //from the same thread as read
+ bool okay=false;
+ for(const ModelAction *tmp=read;tmp!=prreader;) {
+ tmp=tmp->get_node()->get_parent()->get_action();
+ if (tmp->is_read() && tmp->same_thread(read)) {
+ okay=true;
+ break;
+ }
+ }
+ if (okay)
+ continue;
+ }
+ return false;
+ }
+ }
+ }
+ }
+ return true;
+}
+
+
/** 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. */
* require compiler support):
*
* If X --hb-> Y --mo-> Z, then X should not read from Z.
+ * If X --hb-> Y, A --rf-> Y, and A --mo-> Z, then X should not read from Z.
*/
bool ModelExecution::mo_may_allow(const ModelAction *writer, const ModelAction *reader)
{
}
}
+/**
+ * @brief Propagate a modified clock vector to actions later in the execution
+ * order
+ *
+ * After an acquire operation lazily completes a release-sequence
+ * synchronization, we must update all clock vectors for operations later than
+ * the acquire in the execution order.
+ *
+ * @param acquire The ModelAction whose clock vector must be propagated
+ * @param work The work queue to which we can add work items, if this
+ * propagation triggers more updates (e.g., to the modification order)
+ */
+void ModelExecution::propagate_clockvector(ModelAction *acquire, work_queue_t *work)
+{
+ /* Re-check all pending release sequences */
+ work->push_back(CheckRelSeqWorkEntry(NULL));
+ /* Re-check read-acquire for mo_graph edges */
+ work->push_back(MOEdgeWorkEntry(acquire));
+
+ /* propagate synchronization to later actions */
+ action_list_t::reverse_iterator rit = action_trace.rbegin();
+ for (; (*rit) != acquire; rit++) {
+ ModelAction *propagate = *rit;
+ if (acquire->happens_before(propagate)) {
+ synchronize(acquire, propagate);
+ /* Re-check 'propagate' for mo_graph edges */
+ work->push_back(MOEdgeWorkEntry(propagate));
+ }
+ }
+}
+
/**
* Attempt to resolve all stashed operations that might synchronize with a
* release sequence for a given location. This implements the "lazy" portion of
updated = true;
if (updated) {
- /* Re-check all pending release sequences */
- work_queue->push_back(CheckRelSeqWorkEntry(NULL));
- /* 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) != acquire; rit++) {
- ModelAction *propagate = *rit;
- if (acquire->happens_before(propagate)) {
- synchronize(acquire, propagate);
- /* Re-check 'propagate' for mo_graph edges */
- work_queue->push_back(MOEdgeWorkEntry(propagate));
- }
- }
+ /* Propagate the changed clock vector */
+ propagate_clockvector(acquire, work_queue);
}
if (complete) {
it = pending_rel_seqs.erase(it);
* Resolve a Promise with a current write.
* @param write The ModelAction that is fulfilling Promises
* @param promise The Promise to resolve
+ * @param work The work queue, for adding new fixup work
* @return True if the Promise was successfully resolved; false otherwise
*/
-bool ModelExecution::resolve_promise(ModelAction *write, Promise *promise)
+bool ModelExecution::resolve_promise(ModelAction *write, Promise *promise,
+ work_queue_t *work)
{
ModelVector<ModelAction *> actions_to_check;
for (unsigned int i = 0; i < promise->get_num_readers(); i++) {
ModelAction *read = promise->get_reader(i);
- read_from(read, write);
+ if (read_from(read, write)) {
+ /* Propagate the changed clock vector */
+ propagate_clockvector(read, work);
+ }
actions_to_check.push_back(read);
}
/* Make sure the promise's value matches the write's value */
ASSERT(promise->is_compatible(write) && promise->same_value(write));
if (!mo_graph->resolvePromise(promise, write))
- priv->failed_promise = true;
+ priv->hard_failed_promise = true;
/**
* @todo It is possible to end up in an inconsistent state, where a
if (!pread->happens_before(act))
continue;
if (mo_graph->checkPromise(write, promise)) {
- priv->failed_promise = true;
+ priv->hard_failed_promise = true;
return;
}
break;
if (mo_graph->checkReachable(promise, write)) {
if (mo_graph->checkPromise(write, promise)) {
- priv->failed_promise = true;
+ priv->hard_failed_promise = true;
return;
}
}
{
action_list_t::const_iterator it;
- model_print("---------------------------------------------------------------------\n");
+ model_print("------------------------------------------------------------------------------------\n");
+ model_print("# t Action type MO Location Value Rf CV\n");
+ model_print("------------------------------------------------------------------------------------\n");
unsigned int hash = 0;
hash = hash^(hash<<3)^((*it)->hash());
}
model_print("HASH %u\n", hash);
- model_print("---------------------------------------------------------------------\n");
+ model_print("------------------------------------------------------------------------------------\n");
}
#if SUPPORT_MOD_ORDER_DUMP
dumpGraph(buffername);
#endif
- model_print("Execution %d:", get_execution_number());
+ model_print("Execution trace %d:", get_execution_number());
if (isfeasibleprefix()) {
if (is_yieldblocked())
model_print(" YIELD BLOCKED");
if (scheduler->all_threads_sleeping())
model_print(" SLEEP-SET REDUNDANT");
- model_print("\n");
+ if (have_bug_reports())
+ model_print(" DETECTED BUG(S)");
} else
print_infeasibility(" INFEASIBLE");
+ model_print("\n");
+
print_list(&action_trace);
model_print("\n");
+
if (!promises.empty()) {
model_print("Pending promises:\n");
for (unsigned int i = 0; i < promises.size(); i++) {
/* Do not split atomic RMW */
if (curr->is_rmwr())
return get_thread(curr);
+ if (curr->is_write()) {
+// std::memory_order order = curr->get_mo();
+// switch(order) {
+// case std::memory_order_relaxed:
+// return get_thread(curr);
+// case std::memory_order_release:
+// return get_thread(curr);
+// defalut:
+// return NULL;
+// }
+ return NULL;
+ }
+
/* Follow CREATE with the created thread */
+ /* which is not needed, because model.cc takes care of this */
if (curr->get_type() == THREAD_CREATE)
+ return curr->get_thread_operand();
+ if (curr->get_type() == PTHREAD_CREATE) {
return curr->get_thread_operand();
+ }
return NULL;
}
projects / c11tester.git / blobdiff