#include "snapshot-interface.h"
#include "common.h"
#include "clockvector.h"
+#include "cyclegraph.h"
#define INITIAL_THREAD_ID 0
obj_thrd_map(new std::map<void *, std::vector<action_list_t> >()),
thrd_last_action(new std::vector<ModelAction *>(1)),
node_stack(new NodeStack()),
- next_backtrack(NULL)
+ next_backtrack(NULL),
+ cyclegraph(new CycleGraph())
{
}
delete thrd_last_action;
delete node_stack;
delete scheduler;
+ delete cyclegraph;
}
/**
*/
thread_id_t ModelChecker::get_next_replay_thread()
{
- ModelAction *next;
thread_id_t tid;
/* Have we completed exploring the preselected path? */
return THREAD_ID_T_NONE;
/* Else, we are trying to replay an execution */
- next = node_stack->get_next()->get_action();
+ ModelAction * next = node_stack->get_next()->get_action();
if (next == diverge) {
Node *nextnode = next->get_node();
DBG();
num_executions++;
- print_summary();
+
+ if (isfeasible() || DBG_ENABLED())
+ print_summary();
+
if ((diverge = model->get_next_backtrack()) == NULL)
return false;
}
}
+/**
+ * Returns last backtracking point. The model checker will explore a different
+ * path for this point in the next execution.
+ * @return The ModelAction at which the next execution should diverge.
+ */
ModelAction * ModelChecker::get_next_backtrack()
{
ModelAction *next = next_backtrack;
void ModelChecker::check_current_action(void)
{
ModelAction *curr = this->current_action;
- ModelAction *tmp;
- current_action = NULL;
+ bool already_added = false;
+ this->current_action = NULL;
if (!curr) {
DEBUG("trying to push NULL action...\n");
return;
}
- tmp = node_stack->explore_action(curr);
- if (tmp) {
- /* Discard duplicate ModelAction; use action from NodeStack */
+ if (curr->is_rmwc()||curr->is_rmw()) {
+ ModelAction *tmp=process_rmw(curr);
+ already_added = true;
delete curr;
- curr = tmp;
+ curr=tmp;
} else {
- /*
- * Perform one-time actions when pushing new ModelAction onto
- * NodeStack
- */
- curr->create_cv(get_parent_action(curr->get_tid()));
- /* Build may_read_from set */
- if (curr->is_read())
- build_reads_from_past(curr);
+ ModelAction * tmp = node_stack->explore_action(curr);
+ if (tmp) {
+ /* Discard duplicate ModelAction; use action from NodeStack */
+ /* First restore type and order in case of RMW operation */
+ if (curr->is_rmwr())
+ tmp->copy_typeandorder(curr);
+ delete curr;
+ curr = tmp;
+ } else {
+ /*
+ * Perform one-time actions when pushing new ModelAction onto
+ * NodeStack
+ */
+ curr->create_cv(get_parent_action(curr->get_tid()));
+ /* Build may_read_from set */
+ if (curr->is_read())
+ build_reads_from_past(curr);
+ }
}
/* Assign 'creation' parent */
th->set_creation(curr);
}
- nextThread = get_next_replay_thread();
+ /* 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);
+ } else if (curr->is_write()) {
+ w_modification_order(curr);
+ }
+
+ th->set_return_value(value);
+
+ /* Add action to list. */
+ if (!already_added)
+ add_action_to_lists(curr);
+
+ /* 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()) {
+ nextThread = thread_current()->get_id();
+ } else {
+ nextThread = get_next_replay_thread();
+ }
Node *currnode = curr->get_node();
Node *parnode = currnode->get_parent();
next_backtrack = curr;
set_backtracking(curr);
+}
- add_action_to_lists(curr);
+/** @returns whether the current trace is feasible. */
+bool ModelChecker::isfeasible() {
+ return !cyclegraph->checkForCycles();
+}
- /* Assign reads_from values */
- /* TODO: perform release/acquire synchronization here; include
- * reads_from as ModelAction member? */
- 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);
+/** 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);
+ lastread->process_rmw(act);
+ if (act->is_rmw())
+ cyclegraph->addRMWEdge(lastread, lastread->get_reads_from());
+ return lastread;
+}
+
+/**
+ * Updates the cyclegraph with the constraints imposed from the current read.
+ * @param curr The current action. Must be a read.
+ * @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)[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;
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *act = *rit;
+
+ /* 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)
+ cyclegraph->addEdge(rf, prevreadfrom);
+ } else if (rf!=act) {
+ cyclegraph->addEdge(rf, act);
+ }
+ 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)[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)
+ cyclegraph->addEdge(curr, last_seq_cst);
+ }
+
+ /* 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;
+ for (rit = list->rbegin(); rit != list->rend(); rit++) {
+ ModelAction *act = *rit;
+
+ /* Include at most one act per-thread that "happens before" curr */
+ if (act->happens_before(curr)) {
+ if (act->is_read()) {
+ cyclegraph->addEdge(curr, act->get_reads_from());
+ } else
+ cyclegraph->addEdge(curr, act);
+ break;
+ }
+ }
}
- th->set_return_value(value);
}
/**
return parent;
}
+/**
+ * Returns the clock vector for a given thread.
+ * @param tid The thread whose clock vector we want
+ * @return Desired clock vector
+ */
ClockVector * ModelChecker::get_cv(thread_id_t tid) {
return get_parent_action(tid)->get_cv();
}
/* TODO: need a more informative way of reporting errors */
printf("ERROR: may read from uninitialized atomic\n");
}
-
+
if (DBG_ENABLED() || !initialized) {
printf("Reached read action:\n");
curr->print();
curr->get_node()->print_may_read_from();
printf("End printing may_read_from\n");
}
-
+
ASSERT(initialized);
}
scheduler->print();
+ if (!isfeasible())
+ printf("INFEASIBLE EXECUTION!\n");
print_list(action_trace);
printf("\n");
}
*/
int ModelChecker::switch_to_master(ModelAction *act)
{
- Thread *old;
-
DBG();
- old = thread_current();
+ Thread * old = thread_current();
set_current_action(act);
old->set_state(THREAD_READY);
return Thread::swap(old, get_system_context());
projects / model-checker.git / blobdiff