X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=model.cc;h=c3f6372517d591c5016cb91127adf36ae8fadb36;hb=e919b30ee6f7aa594c61fc305e6e88e789dbd700;hp=667c1d57d68ee50ec5790cd0f8f2cf9458eab0c8;hpb=cd61f25e9775d3807c09f0606a69440604ef1821;p=model-checker.git diff --git a/model.cc b/model.cc index 667c1d5..c3f6372 100644 --- a/model.cc +++ b/model.cc @@ -34,7 +34,7 @@ ModelChecker::ModelChecker(struct model_params params) : obj_thrd_map(new HashTable, uintptr_t, 4 >()), promises(new std::vector()), futurevalues(new std::vector()), - pending_acq_rel_seq(new std::vector()), + pending_rel_seqs(new std::vector()), thrd_last_action(new std::vector(1)), node_stack(new NodeStack()), mo_graph(new CycleGraph()), @@ -65,7 +65,7 @@ ModelChecker::~ModelChecker() delete (*promises)[i]; delete promises; - delete pending_acq_rel_seq; + delete pending_rel_seqs; delete thrd_last_action; delete node_stack; @@ -208,7 +208,7 @@ bool ModelChecker::next_execution() } DEBUG("Number of acquires waiting on pending release sequences: %lu\n", - pending_acq_rel_seq->size()); + pending_rel_seqs->size()); if (isfinalfeasible() || DBG_ENABLED()) print_summary(); @@ -236,7 +236,7 @@ ModelAction * ModelChecker::get_last_conflict(ModelAction *act) action_list_t::reverse_iterator rit; for (rit = list->rbegin(); rit != list->rend(); rit++) { ModelAction *prev = *rit; - if (act->is_synchronizing(prev)) + if (prev->could_synchronize_with(act)) return prev; } break; @@ -760,7 +760,7 @@ bool ModelChecker::promises_expired() { /** @return whether the current partial trace must be a prefix of a * feasible trace. */ bool ModelChecker::isfeasibleprefix() { - return promises->size() == 0 && pending_acq_rel_seq->size() == 0; + return promises->size() == 0 && pending_rel_seqs->size() == 0; } /** @return whether the current partial trace is feasible. */ @@ -1114,7 +1114,7 @@ bool ModelChecker::w_modification_order(ModelAction *curr) } added = true; break; - } else if (act->is_read() && !act->is_synchronizing(curr) && + } else if (act->is_read() && !act->could_synchronize_with(curr) && !act->same_thread(curr)) { /* We have an action that: (1) did not happen before us @@ -1174,13 +1174,19 @@ bool ModelChecker::thin_air_constraint_may_allow(const ModelAction * writer, con * @todo Finish lazy updating, when promises are fulfilled in the future * @param rf The action that might be part of a release sequence. Must be a * write. - * @param release_heads A pass-by-reference style return parameter. After + * @param release_heads A pass-by-reference style return parameter. After * execution of this function, release_heads will contain the heads of all the - * relevant release sequences, if any exists + * relevant release sequences, if any exists with certainty + * @param pending A pass-by-reference style return parameter which is only used + * when returning false (i.e., uncertain). Returns most information regarding + * an uncertain release sequence, including any write operations that might + * break the sequence. * @return true, if the ModelChecker is certain that release_heads is complete; * false otherwise */ -bool ModelChecker::release_seq_heads(const ModelAction *rf, rel_heads_list_t *release_heads) const +bool ModelChecker::release_seq_heads(const ModelAction *rf, + rel_heads_list_t *release_heads, + struct release_seq *pending) const { /* Only check for release sequences if there are no cycles */ if (mo_graph->checkForCycles()) @@ -1209,6 +1215,7 @@ bool ModelChecker::release_seq_heads(const ModelAction *rf, rel_heads_list_t *re }; if (!rf) { /* read from future: need to settle this later */ + pending->rf = NULL; return false; /* incomplete */ } @@ -1238,6 +1245,8 @@ bool ModelChecker::release_seq_heads(const ModelAction *rf, rel_heads_list_t *re ASSERT(rf->same_thread(release)); + pending->writes.clear(); + bool certain = true; for (unsigned int i = 0; i < thrd_lists->size(); i++) { if (id_to_int(rf->get_tid()) == (int)i) @@ -1281,14 +1290,21 @@ bool ModelChecker::release_seq_heads(const ModelAction *rf, rel_heads_list_t *re /* release --mo-> act --mo--> rf */ return true; /* complete */ } + /* act may break release sequence */ + pending->writes.push_back(act); certain = false; } if (!future_ordered) - return false; /* This thread is uncertain */ + certain = false; /* This thread is uncertain */ } - if (certain) + if (certain) { release_heads->push_back(release); + pending->writes.clear(); + } else { + pending->release = release; + pending->rf = rf; + } return certain; } @@ -1307,11 +1323,14 @@ bool ModelChecker::release_seq_heads(const ModelAction *rf, rel_heads_list_t *re void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *release_heads) { const ModelAction *rf = act->get_reads_from(); - bool complete; - complete = release_seq_heads(rf, release_heads); - if (!complete) { + struct release_seq *sequence = (struct release_seq *)snapshot_calloc(1, sizeof(struct release_seq)); + sequence->acquire = act; + + if (!release_seq_heads(rf, release_heads, sequence)) { /* add act to 'lazy checking' list */ - pending_acq_rel_seq->push_back(act); + pending_rel_seqs->push_back(sequence); + } else { + snapshot_free(sequence); } } @@ -1331,9 +1350,10 @@ void ModelChecker::get_release_seq_heads(ModelAction *act, rel_heads_list_t *rel bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_queue) { bool updated = false; - std::vector::iterator it = pending_acq_rel_seq->begin(); - while (it != pending_acq_rel_seq->end()) { - ModelAction *act = *it; + std::vector::iterator it = pending_rel_seqs->begin(); + while (it != pending_rel_seqs->end()) { + struct release_seq *pending = *it; + ModelAction *act = pending->acquire; /* Only resolve sequences on the given location, if provided */ if (location && act->get_location() != location) { @@ -1344,7 +1364,7 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ const ModelAction *rf = act->get_reads_from(); rel_heads_list_t release_heads; bool complete; - complete = release_seq_heads(rf, &release_heads); + 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])) @@ -1371,10 +1391,12 @@ bool ModelChecker::resolve_release_sequences(void *location, work_queue_t *work_ } } } - if (complete) - it = pending_acq_rel_seq->erase(it); - else + if (complete) { + it = pending_rel_seqs->erase(it); + snapshot_free(pending); + } else { it++; + } } // If we resolved promises or data races, see if we have realized a data race. @@ -1517,6 +1539,10 @@ bool ModelChecker::resolve_promises(ModelAction *write) } else promise_index++; } + + //Check whether reading these writes has made threads unable to + //resolve promises + for(unsigned int i=0;iget_action(); if (!act->happens_before(curr) && act->is_read() && - !act->is_synchronizing(curr) && + !act->could_synchronize_with(curr) && !act->same_thread(curr) && promise->get_value() == curr->get_value()) { curr->get_node()->set_promise(i); @@ -1561,7 +1587,33 @@ void ModelChecker::check_promises(thread_id_t tid, ClockVector *old_cv, ClockVec } } -/** Checks promises in response to change in ClockVector Threads. */ +/** Checks promises in response to addition to modification order for threads. + * Definitions: + * pthread is the thread that performed the read that created the promise + * + * pread is the read that created the promise + * + * pwrite is either the first write to same location as pread by + * pthread that is sequenced after pread or the value read by the + * first read to the same lcoation as pread by pthread that is + * sequenced after pread.. + * + * 1. If tid=pthread, then we check what other threads are reachable + * through the mode order starting with pwrite. Those threads cannot + * perform a write that will resolve the promise due to modification + * order constraints. + * + * 2. If the tid is not pthread, we check whether pwrite can reach the + * action write through the modification order. If so, that thread + * 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 + * write, or actually did the model action write. + * + * @parem write The ModelAction representing the relevant write. + */ + 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++) { @@ -1572,7 +1624,10 @@ void ModelChecker::mo_check_promises(thread_id_t tid, const ModelAction *write) if ( act->get_location() != location ) continue; - if ( act->get_tid()==tid) { + //same thread as the promise + if ( act->get_tid()==tid ) { + + //do we have a pwrite for the promise, if not, set it if (promise->get_write() == NULL ) { promise->set_write(write); }