#include "common.h"
#include "clockvector.h"
#include "cyclegraph.h"
+#include "promise.h"
#define INITIAL_THREAD_ID 0
ModelChecker *model;
/** @brief Constructor */
-ModelChecker::ModelChecker()
- :
+ModelChecker::ModelChecker(struct model_params params) :
/* Initialize default scheduler */
scheduler(new Scheduler()),
/* First thread created will have id INITIAL_THREAD_ID */
next_thread_id(INITIAL_THREAD_ID),
used_sequence_numbers(0),
-
num_executions(0),
+ params(params),
current_action(NULL),
diverge(NULL),
nextThread(THREAD_ID_T_NONE),
thread_map(new HashTable<int, Thread *, int>()),
obj_map(new HashTable<const void *, action_list_t, uintptr_t, 4>()),
obj_thrd_map(new HashTable<void *, std::vector<action_list_t>, uintptr_t, 4 >()),
+ promises(new std::vector<Promise *>()),
thrd_last_action(new std::vector<ModelAction *>(1)),
node_stack(new NodeStack()),
next_backtrack(NULL),
- cyclegraph(new CycleGraph())
+ cyclegraph(new CycleGraph()),
+ failed_promise(false)
{
}
/** @brief Destructor */
ModelChecker::~ModelChecker()
{
- /* std::map<int, Thread *>::iterator it;
- for (it = thread_map->begin(); it != thread_map->end(); it++)
- delete (*it).second;*/
+ for (int i = 0; i < get_num_threads(); i++)
+ delete thread_map->get(i);
delete thread_map;
delete obj_thrd_map;
used_sequence_numbers = 0;
nextThread = 0;
next_backtrack = NULL;
+ failed_promise = false;
snapshotObject->backTrackBeforeStep(0);
}
if (next == diverge) {
Node *nextnode = next->get_node();
/* Reached divergence point */
- if (nextnode->increment_read_from()) {
- /* The next node will read from a different value */
+ if (nextnode->increment_promise()) {
+ /* The next node will try to satisfy a different set of promises. */
+ tid = next->get_tid();
+ node_stack->pop_restofstack(2);
+ } else if (nextnode->increment_read_from()) {
+ /* The next node will read from a different value. */
+ tid = next->get_tid();
+ node_stack->pop_restofstack(2);
+ } else if (nextnode->increment_future_value()) {
+ /* The next node will try to read from a different future value. */
tid = next->get_tid();
node_stack->pop_restofstack(2);
} else {
num_executions++;
- if (isfeasible() || DBG_ENABLED())
+ if (isfinalfeasible() || DBG_ENABLED())
print_summary();
if ((diverge = model->get_next_backtrack()) == NULL)
return NULL;
}
/* linear search: from most recent to oldest */
- action_list_t *list = obj_map->ensureptr(act->get_location());
+ action_list_t *list = obj_map->get_safe_ptr(act->get_location());
action_list_t::reverse_iterator rit;
for (rit = list->rbegin(); rit != list->rend(); rit++) {
ModelAction *prev = *rit;
return;
}
- if (curr->is_rmwc()||curr->is_rmw()) {
- ModelAction *tmp=process_rmw(curr);
+ if (curr->is_rmwc() || curr->is_rmw()) {
+ ModelAction *tmp = process_rmw(curr);
already_added = true;
delete curr;
- curr=tmp;
+ curr = tmp;
} else {
ModelAction * tmp = node_stack->explore_action(curr);
if (tmp) {
/* First restore type and order in case of RMW operation */
if (curr->is_rmwr())
tmp->copy_typeandorder(curr);
+
+ /* If we have diverged, we need to reset the clock vector. */
+ if (diverge == NULL)
+ tmp->create_cv(get_parent_action(tmp->get_tid()));
+
delete curr;
curr = tmp;
} else {
/* Build may_read_from set */
if (curr->is_read())
build_reads_from_past(curr);
+ if (curr->is_write())
+ compute_promises(curr);
}
}
th->set_creation(curr);
}
+ /* Deal with new thread */
+ if (curr->get_type() == THREAD_START)
+ check_promises(NULL, curr->get_cv());
+
/* Assign reads_from values */
Thread *th = get_thread(curr->get_tid());
uint64_t value = VALUE_NONE;
if (curr->is_read()) {
const ModelAction *reads_from = curr->get_node()->get_read_from();
- value = reads_from->get_value();
- /* Assign reads_from, perform release/acquire synchronization */
- curr->read_from(reads_from);
- r_modification_order(curr,reads_from);
+ if (reads_from != NULL) {
+ value = reads_from->get_value();
+ /* Assign reads_from, perform release/acquire synchronization */
+ curr->read_from(reads_from);
+ r_modification_order(curr,reads_from);
+ } else {
+ /* Read from future value */
+ value = curr->get_node()->get_future_value();
+ curr->read_from(NULL);
+ Promise * valuepromise = new Promise(curr, value);
+ promises->push_back(valuepromise);
+ }
} else if (curr->is_write()) {
w_modification_order(curr);
+ resolve_promises(curr);
}
th->set_return_value(value);
if (!already_added)
add_action_to_lists(curr);
- /* Is there a better interface for setting the next thread rather
+ /** @todo Is there a better interface for setting the next thread rather
than this field/convoluted approach? Perhaps like just returning
it or something? */
/* Do not split atomic actions. */
- if (curr->is_rmwr()) {
+ if (curr->is_rmwr())
nextThread = thread_current()->get_id();
- } else {
+ else
nextThread = get_next_replay_thread();
- }
Node *currnode = curr->get_node();
Node *parnode = currnode->get_parent();
- if (!parnode->backtrack_empty()||!currnode->readsfrom_empty())
+ if (!parnode->backtrack_empty() || !currnode->read_from_empty() ||
+ !currnode->future_value_empty() || !currnode->promise_empty())
if (!next_backtrack || *curr > *next_backtrack)
next_backtrack = curr;
set_backtracking(curr);
}
-/** @returns whether the current trace is feasible. */
+/** @returns whether the current partial trace is feasible. */
bool ModelChecker::isfeasible() {
- return !cyclegraph->checkForCycles();
+ return !cyclegraph->checkForCycles() && !failed_promise;
+}
+
+/** Returns whether the current completed trace is feasible. */
+bool ModelChecker::isfinalfeasible() {
+ return isfeasible() && promises->size() == 0;
}
/** Close out a RMWR by converting previous RMWR into a RMW or READ. */
ModelAction * ModelChecker::process_rmw(ModelAction * act) {
int tid = id_to_int(act->get_tid());
- ModelAction *lastread=get_last_action(tid);
+ ModelAction *lastread = get_last_action(tid);
lastread->process_rmw(act);
if (act->is_rmw())
cyclegraph->addRMWEdge(lastread, lastread->get_reads_from());
* @param rf The action that curr reads from. Must be a write.
*/
void ModelChecker::r_modification_order(ModelAction * curr, const ModelAction *rf) {
- std::vector<action_list_t> *thrd_lists = obj_thrd_map->ensureptr(curr->get_location());
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->get_safe_ptr(curr->get_location());
unsigned int i;
ASSERT(curr->is_read());
/* Include at most one act per-thread that "happens before" curr */
if (act->happens_before(curr)) {
if (act->is_read()) {
- const ModelAction * prevreadfrom=act->get_reads_from();
- if (rf!=prevreadfrom)
+ const ModelAction * prevreadfrom = act->get_reads_from();
+ if (prevreadfrom != NULL && rf != prevreadfrom)
cyclegraph->addEdge(rf, prevreadfrom);
- } else if (rf!=act) {
+ } else if (rf != act) {
cyclegraph->addEdge(rf, act);
}
break;
}
}
+/** Updates the cyclegraph with the constraints imposed from the
+ * current read. */
+void ModelChecker::post_r_modification_order(ModelAction * curr, const ModelAction *rf) {
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->get_safe_ptr(curr->get_location());
+ unsigned int i;
+ ASSERT(curr->is_read());
+
+ /* Iterate over all threads */
+ for (i = 0; i < thrd_lists->size(); i++) {
+ /* Iterate over actions in thread, starting from most recent */
+ action_list_t *list = &(*thrd_lists)[i];
+ action_list_t::reverse_iterator rit;
+ ModelAction *lastact = NULL;
+
+ /* Find last action that happens after curr */
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *act = *rit;
+ if (curr->happens_before(act)) {
+ lastact = act;
+ } else
+ break;
+ }
+
+ /* Include at most one act per-thread that "happens before" curr */
+ if (lastact != NULL) {
+ if (lastact->is_read()) {
+ const ModelAction * postreadfrom = lastact->get_reads_from();
+ if (postreadfrom != NULL&&rf != postreadfrom)
+ cyclegraph->addEdge(postreadfrom, rf);
+ } else if (rf != lastact) {
+ cyclegraph->addEdge(lastact, rf);
+ }
+ break;
+ }
+ }
+}
+
/**
* Updates the cyclegraph with the constraints imposed from the current write.
* @param curr The current action. Must be a write.
*/
void ModelChecker::w_modification_order(ModelAction * curr) {
- std::vector<action_list_t> *thrd_lists = obj_thrd_map->ensureptr(curr->get_location());
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->get_safe_ptr(curr->get_location());
unsigned int i;
ASSERT(curr->is_write());
if (curr->is_seqcst()) {
/* We have to at least see the last sequentially consistent write,
so we are initialized. */
- ModelAction * last_seq_cst=get_last_seq_cst(curr->get_location());
- if (last_seq_cst!=NULL)
+ ModelAction * last_seq_cst = get_last_seq_cst(curr->get_location());
+ if (last_seq_cst != NULL)
cyclegraph->addEdge(curr, last_seq_cst);
}
/* Include at most one act per-thread that "happens before" curr */
if (act->happens_before(curr)) {
- if (act->is_read()) {
+ if (act->is_read())
cyclegraph->addEdge(curr, act->get_reads_from());
- } else
+ else
cyclegraph->addEdge(curr, act);
break;
+ } else if (act->is_read() && !act->is_synchronizing(curr) &&
+ !act->same_thread(curr)) {
+ /* We have an action that:
+ (1) did not happen before us
+ (2) is a read and we are a write
+ (3) cannot synchronize with us
+ (4) is in a different thread
+ =>
+ that read could potentially read from our write.
+ */
+ if (act->get_node()->add_future_value(curr->get_value()) &&
+ (!next_backtrack || *act > *next_backtrack))
+ next_backtrack = act;
}
}
}
int tid = id_to_int(act->get_tid());
action_trace->push_back(act);
- obj_map->ensureptr(act->get_location())->push_back(act);
+ obj_map->get_safe_ptr(act->get_location())->push_back(act);
- std::vector<action_list_t> *vec = obj_thrd_map->ensureptr(act->get_location());
+ std::vector<action_list_t> *vec = obj_thrd_map->get_safe_ptr(act->get_location());
if (tid >= (int)vec->size())
vec->resize(next_thread_id);
(*vec)[tid].push_back(act);
*/
ModelAction * ModelChecker::get_last_seq_cst(const void *location)
{
- action_list_t *list = obj_map->ensureptr(location);
+ action_list_t *list = obj_map->get_safe_ptr(location);
/* Find: max({i in dom(S) | seq_cst(t_i) && isWrite(t_i) && samevar(t_i, t)}) */
action_list_t::reverse_iterator rit;
for (rit = list->rbegin(); rit != list->rend(); rit++)
return get_parent_action(tid)->get_cv();
}
+
+/** Resolve the given promises. */
+
+void ModelChecker::resolve_promises(ModelAction *write) {
+ for (unsigned int i = 0, promise_index = 0;promise_index<promises->size(); i++) {
+ Promise * promise = (*promises)[promise_index];
+ if (write->get_node()->get_promise(i)) {
+ ModelAction * read = promise->get_action();
+ read->read_from(write);
+ r_modification_order(read, write);
+ post_r_modification_order(read, write);
+ promises->erase(promises->begin()+promise_index);
+ } else
+ promise_index++;
+ }
+}
+
+/** Compute the set of promises that could potentially be satisfied by
+ * this action. */
+
+void ModelChecker::compute_promises(ModelAction *curr) {
+ for (unsigned int i = 0;i<promises->size();i++) {
+ Promise * promise = (*promises)[i];
+ const ModelAction * act = promise->get_action();
+ if (!act->happens_before(curr)&&
+ act->is_read()&&
+ !act->is_synchronizing(curr)&&
+ !act->same_thread(curr)&&
+ promise->get_value() == curr->get_value()) {
+ curr->get_node()->set_promise(i);
+ }
+ }
+}
+
+/** Checks promises in response to change in ClockVector Threads. */
+
+void ModelChecker::check_promises(ClockVector *old_cv, ClockVector * merge_cv) {
+ for (unsigned int i = 0;i<promises->size();i++) {
+ Promise * promise = (*promises)[i];
+ const ModelAction * act = promise->get_action();
+ if ((old_cv == NULL||!old_cv->synchronized_since(act))&&
+ merge_cv->synchronized_since(act)) {
+ //This thread is no longer able to send values back to satisfy the promise
+ int num_synchronized_threads = promise->increment_threads();
+ if (num_synchronized_threads == model->get_num_threads()) {
+ //Promise has failed
+ failed_promise = true;
+ return;
+ }
+ }
+ }
+}
+
/**
* Build up an initial set of all past writes that this 'read' action may read
* from. This set is determined by the clock vector's "happens before"
*/
void ModelChecker::build_reads_from_past(ModelAction *curr)
{
- std::vector<action_list_t> *thrd_lists = obj_thrd_map->ensureptr(curr->get_location());
+ std::vector<action_list_t> *thrd_lists = obj_thrd_map->get_safe_ptr(curr->get_location());
unsigned int i;
ASSERT(curr->is_read());
printf("---------------------------------------------------------------------\n");
}
-void ModelChecker::print_summary(void)
+void ModelChecker::print_summary()
{
printf("\n");
printf("Number of executions: %d\n", num_executions);
scheduler->print();
- if (!isfeasible())
+ if (!isfinalfeasible())
printf("INFEASIBLE EXECUTION!\n");
print_list(action_trace);
printf("\n");
}
-int ModelChecker::add_thread(Thread *t)
+/**
+ * Add a Thread to the system for the first time. Should only be called once
+ * per thread.
+ * @param t The Thread to add
+ */
+void ModelChecker::add_thread(Thread *t)
{
thread_map->put(id_to_int(t->get_id()), t);
scheduler->add_thread(t);
- return 0;
}
void ModelChecker::remove_thread(Thread *t)
Thread * old = thread_current();
set_current_action(act);
old->set_state(THREAD_READY);
- return Thread::swap(old, get_system_context());
+ return Thread::swap(old, &system_context);
+}
+
+/**
+ * Takes the next step in the execution, if possible.
+ * @return Returns true (success) if a step was taken and false otherwise.
+ */
+bool ModelChecker::take_step() {
+ Thread *curr, *next;
+
+ curr = thread_current();
+ if (curr) {
+ if (curr->get_state() == THREAD_READY) {
+ check_current_action();
+ scheduler->add_thread(curr);
+ } else if (curr->get_state() == THREAD_RUNNING) {
+ /* Stopped while running; i.e., completed */
+ curr->complete();
+ } else {
+ ASSERT(false);
+ }
+ }
+ next = scheduler->next_thread();
+
+ /* Infeasible -> don't take any more steps */
+ if (!isfeasible())
+ return false;
+
+ if (next)
+ next->set_state(THREAD_RUNNING);
+ DEBUG("(%d, %d)\n", curr ? curr->get_id() : -1, next ? next->get_id() : -1);
+
+ /* next == NULL -> don't take any more steps */
+ if (!next)
+ return false;
+ /* Return false only if swap fails with an error */
+ return (Thread::swap(&system_context, next) == 0);
+}
+
+/** Runs the current execution until threre are no more steps to take. */
+void ModelChecker::finish_execution() {
+ DBG();
+
+ while (take_step());
}
projects / c11tester.git / blobdiff